/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2018 Ayke van Laethem
 * Copyright (c) 2019-2020 Jim Mussared
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "py/binary.h"
#include "py/gc.h"
#include "py/misc.h"
#include "py/mperrno.h"
#include "py/mphal.h"
#include "py/obj.h"
#include "py/objarray.h"
#include "py/objstr.h"
#include "py/qstr.h"
#include "py/runtime.h"
#include "extmod/modbluetooth.h"
#include <string.h>

#if MICROPY_PY_BLUETOOTH

#if !MICROPY_ENABLE_SCHEDULER
#error modbluetooth requires MICROPY_ENABLE_SCHEDULER
#endif

#define MP_BLUETOOTH_CONNECT_DEFAULT_SCAN_DURATION_MS 2000

#define MICROPY_PY_BLUETOOTH_MAX_EVENT_DATA_TUPLE_LEN 5

// This formula is intended to allow queuing the data of a large characteristic
// while still leaving room for a couple of normal (small, fixed size) events.
#define MICROPY_PY_BLUETOOTH_MAX_EVENT_DATA_BYTES_LEN(ringbuf_size) (MAX((int)((ringbuf_size) / 2), (int)(ringbuf_size) - 64))

STATIC const mp_obj_type_t bluetooth_ble_type;
STATIC const mp_obj_type_t bluetooth_uuid_type;

typedef struct {
    mp_obj_base_t base;
    mp_obj_t irq_handler;
    bool irq_scheduled;
    mp_obj_t irq_data_tuple;
    uint8_t irq_data_addr_bytes[6];
    uint16_t irq_data_data_alloc;
    uint8_t *irq_data_data_bytes;
    mp_obj_str_t irq_data_addr;
    mp_obj_str_t irq_data_data;
    mp_obj_bluetooth_uuid_t irq_data_uuid;
    ringbuf_t ringbuf;
    #if MICROPY_PY_BLUETOOTH_GATTS_ON_READ_CALLBACK
    mp_obj_t irq_read_request_data_tuple;
    #endif
} mp_obj_bluetooth_ble_t;

// TODO: this seems like it could be generic?
STATIC mp_obj_t bluetooth_handle_errno(int err) {
    if (err != 0) {
        mp_raise_OSError(err);
    }
    return mp_const_none;
}

// ----------------------------------------------------------------------------
// UUID object
// ----------------------------------------------------------------------------

STATIC mp_obj_t bluetooth_uuid_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    (void)type;

    mp_arg_check_num(n_args, n_kw, 1, 1, false);

    mp_obj_bluetooth_uuid_t *self = m_new_obj(mp_obj_bluetooth_uuid_t);
    self->base.type = &bluetooth_uuid_type;

    if (mp_obj_is_int(all_args[0])) {
        self->type = MP_BLUETOOTH_UUID_TYPE_16;
        mp_int_t value = mp_obj_get_int(all_args[0]);
        if (value > 65535) {
            mp_raise_ValueError(MP_ERROR_TEXT("invalid UUID"));
        }
        self->data[0] = value & 0xff;
        self->data[1] = (value >> 8) & 0xff;
    } else {
        mp_buffer_info_t uuid_bufinfo = {0};
        mp_get_buffer_raise(all_args[0], &uuid_bufinfo, MP_BUFFER_READ);
        if (uuid_bufinfo.len == 2 || uuid_bufinfo.len == 4 || uuid_bufinfo.len == 16) {
            // Bytes data -- infer UUID type from length and copy data.
            self->type = uuid_bufinfo.len;
            memcpy(self->data, uuid_bufinfo.buf, self->type);
        } else {
            // Assume UUID string (e.g. '6E400001-B5A3-F393-E0A9-E50E24DCCA9E')
            self->type = MP_BLUETOOTH_UUID_TYPE_128;
            int uuid_i = 32;
            for (size_t i = 0; i < uuid_bufinfo.len; i++) {
                char c = ((char *)uuid_bufinfo.buf)[i];
                if (c == '-') {
                    continue;
                }
                if (!unichar_isxdigit(c)) {
                    mp_raise_ValueError(MP_ERROR_TEXT("invalid char in UUID"));
                }
                c = unichar_xdigit_value(c);
                uuid_i--;
                if (uuid_i < 0) {
                    mp_raise_ValueError(MP_ERROR_TEXT("UUID too long"));
                }
                if (uuid_i % 2 == 0) {
                    // lower nibble
                    self->data[uuid_i / 2] |= c;
                } else {
                    // upper nibble
                    self->data[uuid_i / 2] = c << 4;
                }
            }
            if (uuid_i > 0) {
                mp_raise_ValueError(MP_ERROR_TEXT("UUID too short"));
            }
        }
    }

    return MP_OBJ_FROM_PTR(self);
}

STATIC mp_obj_t bluetooth_uuid_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
    mp_obj_bluetooth_uuid_t *self = MP_OBJ_TO_PTR(self_in);
    switch (op) {
        case MP_UNARY_OP_HASH: {
            // Use the QSTR hash function.
            return MP_OBJ_NEW_SMALL_INT(qstr_compute_hash(self->data, self->type));
        }
        default:
            return MP_OBJ_NULL;      // op not supported
    }
}

STATIC mp_obj_t bluetooth_uuid_binary_op(mp_binary_op_t op, mp_obj_t lhs_in, mp_obj_t rhs_in) {
    if (!mp_obj_is_type(rhs_in, &bluetooth_uuid_type)) {
        return MP_OBJ_NULL;
    }

    mp_obj_bluetooth_uuid_t *lhs = MP_OBJ_TO_PTR(lhs_in);
    mp_obj_bluetooth_uuid_t *rhs = MP_OBJ_TO_PTR(rhs_in);
    switch (op) {
        case MP_BINARY_OP_EQUAL:
        case MP_BINARY_OP_LESS:
        case MP_BINARY_OP_LESS_EQUAL:
        case MP_BINARY_OP_MORE:
        case MP_BINARY_OP_MORE_EQUAL:
            if (lhs->type == rhs->type) {
                return mp_obj_new_bool(mp_seq_cmp_bytes(op, lhs->data, lhs->type, rhs->data, rhs->type));
            } else {
                return mp_binary_op(op, MP_OBJ_NEW_SMALL_INT(lhs->type), MP_OBJ_NEW_SMALL_INT(rhs->type));
            }

        default:
            return MP_OBJ_NULL; // op not supported
    }
}

STATIC void bluetooth_uuid_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
    (void)kind;

    mp_obj_bluetooth_uuid_t *self = MP_OBJ_TO_PTR(self_in);
    mp_printf(print, "UUID(%s", self->type <= 4 ? "0x" : "'");
    for (int i = 0; i < self->type; ++i) {
        if (i == 4 || i == 6 || i == 8 || i == 10) {
            mp_printf(print, "-");
        }
        mp_printf(print, "%02x", self->data[self->type - 1 - i]);
    }
    if (self->type == MP_BLUETOOTH_UUID_TYPE_128) {
        mp_printf(print, "'");
    }
    mp_printf(print, ")");
}

STATIC mp_int_t bluetooth_uuid_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags) {
    mp_obj_bluetooth_uuid_t *self = MP_OBJ_TO_PTR(self_in);

    if (flags != MP_BUFFER_READ) {
        return 1;
    }

    bufinfo->buf = self->data;
    bufinfo->len = self->type;
    bufinfo->typecode = 'B';
    return 0;
}

#if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE

STATIC void ringbuf_put_uuid(ringbuf_t *ringbuf, mp_obj_bluetooth_uuid_t *uuid) {
    assert(ringbuf_free(ringbuf) >= (size_t)uuid->type + 1);
    ringbuf_put(ringbuf, uuid->type);
    for (int i = 0; i < uuid->type; ++i) {
        ringbuf_put(ringbuf, uuid->data[i]);
    }
}

STATIC void ringbuf_get_uuid(ringbuf_t *ringbuf, mp_obj_bluetooth_uuid_t *uuid) {
    assert(ringbuf_avail(ringbuf) >= 1);
    uuid->type = ringbuf_get(ringbuf);
    assert(ringbuf_avail(ringbuf) >= uuid->type);
    for (int i = 0; i < uuid->type; ++i) {
        uuid->data[i] = ringbuf_get(ringbuf);
    }
}
#endif // MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE

STATIC const mp_obj_type_t bluetooth_uuid_type = {
    { &mp_type_type },
    .name = MP_QSTR_UUID,
    .make_new = bluetooth_uuid_make_new,
    .unary_op = bluetooth_uuid_unary_op,
    .binary_op = bluetooth_uuid_binary_op,
    .locals_dict = NULL,
    .print = bluetooth_uuid_print,
    .buffer_p = { .get_buffer = bluetooth_uuid_get_buffer },
};

// ----------------------------------------------------------------------------
// Bluetooth object: General
// ----------------------------------------------------------------------------

STATIC mp_obj_t bluetooth_ble_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
    (void)type;
    (void)n_args;
    (void)n_kw;
    (void)all_args;
    if (MP_STATE_VM(bluetooth) == MP_OBJ_NULL) {
        mp_obj_bluetooth_ble_t *o = m_new0(mp_obj_bluetooth_ble_t, 1);
        o->base.type = &bluetooth_ble_type;

        o->irq_handler = mp_const_none;

        // Pre-allocate the event data tuple to prevent needing to allocate in the IRQ handler.
        o->irq_data_tuple = mp_obj_new_tuple(MICROPY_PY_BLUETOOTH_MAX_EVENT_DATA_TUPLE_LEN, NULL);

        #if MICROPY_PY_BLUETOOTH_GATTS_ON_READ_CALLBACK
        // Pre-allocate a separate data tuple for the read request "hard" irq.
        o->irq_read_request_data_tuple = mp_obj_new_tuple(2, NULL);
        #endif

        // Pre-allocated buffers for address, payload and uuid.
        o->irq_data_addr.base.type = &mp_type_bytes;
        o->irq_data_addr.data = o->irq_data_addr_bytes;
        o->irq_data_data_alloc = MICROPY_PY_BLUETOOTH_MAX_EVENT_DATA_BYTES_LEN(MICROPY_PY_BLUETOOTH_RINGBUF_SIZE);
        o->irq_data_data.base.type = &mp_type_bytes;
        o->irq_data_data.data = m_new(uint8_t, o->irq_data_data_alloc);
        o->irq_data_uuid.base.type = &bluetooth_uuid_type;

        // Allocate the default ringbuf.
        ringbuf_alloc(&o->ringbuf, MICROPY_PY_BLUETOOTH_RINGBUF_SIZE);

        MP_STATE_VM(bluetooth) = MP_OBJ_FROM_PTR(o);
    }
    return MP_STATE_VM(bluetooth);
}

STATIC mp_obj_t bluetooth_ble_active(size_t n_args, const mp_obj_t *args) {
    if (n_args == 2) {
        // Boolean enable/disable argument supplied, set current state.
        if (mp_obj_is_true(args[1])) {
            int err = mp_bluetooth_init();
            bluetooth_handle_errno(err);
        } else {
            mp_bluetooth_deinit();
        }
    }
    // Return current state.
    return mp_obj_new_bool(mp_bluetooth_is_active());
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_active_obj, 1, 2, bluetooth_ble_active);

STATIC mp_obj_t bluetooth_ble_config(size_t n_args, const mp_obj_t *args, mp_map_t *kwargs) {
    mp_obj_bluetooth_ble_t *self = MP_OBJ_TO_PTR(args[0]);

    if (kwargs->used == 0) {
        // Get config value
        if (n_args != 2) {
            mp_raise_TypeError(MP_ERROR_TEXT("must query one param"));
        }

        switch (mp_obj_str_get_qstr(args[1])) {
            case MP_QSTR_gap_name: {
                const uint8_t *buf;
                size_t len = mp_bluetooth_gap_get_device_name(&buf);
                return mp_obj_new_bytes(buf, len);
            }
            case MP_QSTR_mac: {
                uint8_t addr_type;
                uint8_t addr[6];
                mp_bluetooth_get_current_address(&addr_type, addr);
                mp_obj_t items[] = { MP_OBJ_NEW_SMALL_INT(addr_type), mp_obj_new_bytes(addr, MP_ARRAY_SIZE(addr)) };
                return mp_obj_new_tuple(2, items);
            }
            case MP_QSTR_rxbuf:
                return mp_obj_new_int(self->ringbuf.size);
            case MP_QSTR_mtu:
                return mp_obj_new_int(mp_bluetooth_get_preferred_mtu());
            default:
                mp_raise_ValueError(MP_ERROR_TEXT("unknown config param"));
        }
    } else {
        // Set config value(s)
        if (n_args != 1) {
            mp_raise_TypeError(MP_ERROR_TEXT("can't specify pos and kw args"));
        }

        for (size_t i = 0; i < kwargs->alloc; ++i) {
            if (MP_MAP_SLOT_IS_FILLED(kwargs, i)) {
                mp_map_elem_t *e = &kwargs->table[i];
                switch (mp_obj_str_get_qstr(e->key)) {
                    case MP_QSTR_gap_name: {
                        mp_buffer_info_t bufinfo;
                        mp_get_buffer_raise(e->value, &bufinfo, MP_BUFFER_READ);
                        bluetooth_handle_errno(mp_bluetooth_gap_set_device_name(bufinfo.buf, bufinfo.len));
                        break;
                    }
                    case MP_QSTR_rxbuf: {
                        // Determine new buffer sizes
                        mp_int_t ringbuf_alloc = mp_obj_get_int(e->value);
                        if (ringbuf_alloc < 16 || ringbuf_alloc > 0xffff) {
                            mp_raise_ValueError(NULL);
                        }
                        size_t irq_data_alloc = MICROPY_PY_BLUETOOTH_MAX_EVENT_DATA_BYTES_LEN(ringbuf_alloc);

                        // Allocate new buffers
                        uint8_t *ringbuf = m_new(uint8_t, ringbuf_alloc);
                        uint8_t *irq_data = m_new(uint8_t, irq_data_alloc);

                        // Get old buffer sizes and pointers
                        uint8_t *old_ringbuf_buf = self->ringbuf.buf;
                        size_t old_ringbuf_alloc = self->ringbuf.size;
                        uint8_t *old_irq_data_buf = (uint8_t *)self->irq_data_data.data;
                        size_t old_irq_data_alloc = self->irq_data_data_alloc;

                        // Atomically update the ringbuf and irq data
                        MICROPY_PY_BLUETOOTH_ENTER
                        self->ringbuf.size = ringbuf_alloc;
                        self->ringbuf.buf = ringbuf;
                        self->ringbuf.iget = 0;
                        self->ringbuf.iput = 0;
                        self->irq_data_data_alloc = irq_data_alloc;
                        self->irq_data_data.data = irq_data;
                        MICROPY_PY_BLUETOOTH_EXIT

                        // Free old buffers
                        m_del(uint8_t, old_ringbuf_buf, old_ringbuf_alloc);
                        m_del(uint8_t, old_irq_data_buf, old_irq_data_alloc);
                        break;
                    }
                    case MP_QSTR_mtu: {
                        mp_int_t mtu = mp_obj_get_int(e->value);
                        bluetooth_handle_errno(mp_bluetooth_set_preferred_mtu(mtu));
                        break;
                    }
                    case MP_QSTR_addr_mode: {
                        mp_int_t addr_mode = mp_obj_get_int(e->value);
                        mp_bluetooth_set_address_mode(addr_mode);
                        break;
                    }
                    default:
                        mp_raise_ValueError(MP_ERROR_TEXT("unknown config param"));
                }
            }
        }

        return mp_const_none;
    }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bluetooth_ble_config_obj, 1, bluetooth_ble_config);

STATIC mp_obj_t bluetooth_ble_irq(mp_obj_t self_in, mp_obj_t handler_in) {
    (void)self_in;
    if (handler_in != mp_const_none && !mp_obj_is_callable(handler_in)) {
        mp_raise_ValueError(MP_ERROR_TEXT("invalid handler"));
    }

    // Update the callback.
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    o->irq_handler = handler_in;
    MICROPY_PY_BLUETOOTH_EXIT

    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_irq_obj, bluetooth_ble_irq);

// ----------------------------------------------------------------------------
// Bluetooth object: GAP
// ----------------------------------------------------------------------------

STATIC mp_obj_t bluetooth_ble_gap_advertise(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
    enum { ARG_interval_us, ARG_adv_data, ARG_resp_data, ARG_connectable };
    static const mp_arg_t allowed_args[] = {
        { MP_QSTR_interval_us, MP_ARG_OBJ, {.u_obj = MP_OBJ_NEW_SMALL_INT(500000)} },
        { MP_QSTR_adv_data, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
        { MP_QSTR_resp_data, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_rom_obj = MP_ROM_NONE} },
        { MP_QSTR_connectable, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_rom_obj = MP_ROM_TRUE} },
    };
    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
    mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);

    if (args[ARG_interval_us].u_obj == mp_const_none) {
        mp_bluetooth_gap_advertise_stop();
        return mp_const_none;
    }

    mp_int_t interval_us = mp_obj_get_int(args[ARG_interval_us].u_obj);
    bool connectable = mp_obj_is_true(args[ARG_connectable].u_obj);

    mp_buffer_info_t adv_bufinfo = {0};
    if (args[ARG_adv_data].u_obj != mp_const_none) {
        mp_get_buffer_raise(args[ARG_adv_data].u_obj, &adv_bufinfo, MP_BUFFER_READ);
    }

    mp_buffer_info_t resp_bufinfo = {0};
    if (args[ARG_resp_data].u_obj != mp_const_none) {
        mp_get_buffer_raise(args[ARG_resp_data].u_obj, &resp_bufinfo, MP_BUFFER_READ);
    }

    return bluetooth_handle_errno(mp_bluetooth_gap_advertise_start(connectable, interval_us, adv_bufinfo.buf, adv_bufinfo.len, resp_bufinfo.buf, resp_bufinfo.len));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_KW(bluetooth_ble_gap_advertise_obj, 1, bluetooth_ble_gap_advertise);

STATIC int bluetooth_gatts_register_service(mp_obj_t uuid_in, mp_obj_t characteristics_in, uint16_t **handles, size_t *num_handles) {
    if (!mp_obj_is_type(uuid_in, &bluetooth_uuid_type)) {
        mp_raise_ValueError(MP_ERROR_TEXT("invalid service UUID"));
    }
    mp_obj_bluetooth_uuid_t *service_uuid = MP_OBJ_TO_PTR(uuid_in);

    mp_obj_t len_in = mp_obj_len(characteristics_in);
    size_t len = mp_obj_get_int(len_in);
    mp_obj_iter_buf_t iter_buf;
    mp_obj_t iterable = mp_getiter(characteristics_in, &iter_buf);
    mp_obj_t characteristic_obj;

    // Lists of characteristic uuids and flags.
    mp_obj_bluetooth_uuid_t **characteristic_uuids = m_new(mp_obj_bluetooth_uuid_t *, len);
    uint8_t *characteristic_flags = m_new(uint8_t, len);

    // Flattened list of descriptor uuids and flags. Grows (realloc) as more descriptors are encountered.
    mp_obj_bluetooth_uuid_t **descriptor_uuids = NULL;
    uint8_t *descriptor_flags = NULL;
    // How many descriptors in the flattened list per characteristic.
    uint8_t *num_descriptors = m_new(uint8_t, len);

    // Inititally allocate enough room for the number of characteristics.
    // Will be grown to accommodate descriptors as necessary.
    *num_handles = len;
    *handles = m_new(uint16_t, *num_handles);

    // Extract out characteristic uuids & flags.

    int characteristic_index = 0; // characteristic index.
    int handle_index = 0; // handle index.
    int descriptor_index = 0; // descriptor index.
    while ((characteristic_obj = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
        // (uuid, flags, (optional descriptors),)
        size_t characteristic_len;
        mp_obj_t *characteristic_items;
        mp_obj_get_array(characteristic_obj, &characteristic_len, &characteristic_items);

        if (characteristic_len < 2 || characteristic_len > 3) {
            mp_raise_ValueError(MP_ERROR_TEXT("invalid characteristic tuple"));
        }
        mp_obj_t uuid_obj = characteristic_items[0];
        if (!mp_obj_is_type(uuid_obj, &bluetooth_uuid_type)) {
            mp_raise_ValueError(MP_ERROR_TEXT("invalid characteristic UUID"));
        }

        (*handles)[handle_index++] = 0xffff;

        // Optional third element, iterable of descriptors.
        if (characteristic_len >= 3) {
            mp_obj_t descriptors_len_in = mp_obj_len(characteristic_items[2]);
            num_descriptors[characteristic_index] = mp_obj_get_int(descriptors_len_in);

            if (num_descriptors[characteristic_index] == 0) {
                continue;
            }

            // Grow the flattened uuids and flags arrays with this many more descriptors.
            descriptor_uuids = m_renew(mp_obj_bluetooth_uuid_t *, descriptor_uuids, descriptor_index, descriptor_index + num_descriptors[characteristic_index]);
            descriptor_flags = m_renew(uint8_t, descriptor_flags, descriptor_index, descriptor_index + num_descriptors[characteristic_index]);

            // Also grow the handles array.
            *handles = m_renew(uint16_t, *handles, *num_handles, *num_handles + num_descriptors[characteristic_index]);

            mp_obj_iter_buf_t iter_buf_desc;
            mp_obj_t iterable_desc = mp_getiter(characteristic_items[2], &iter_buf_desc);
            mp_obj_t descriptor_obj;

            // Extract out descriptors for this characteristic.
            while ((descriptor_obj = mp_iternext(iterable_desc)) != MP_OBJ_STOP_ITERATION) {
                // (uuid, flags,)
                mp_obj_t *descriptor_items;
                mp_obj_get_array_fixed_n(descriptor_obj, 2, &descriptor_items);
                mp_obj_t desc_uuid_obj = descriptor_items[0];
                if (!mp_obj_is_type(desc_uuid_obj, &bluetooth_uuid_type)) {
                    mp_raise_ValueError(MP_ERROR_TEXT("invalid descriptor UUID"));
                }

                descriptor_uuids[descriptor_index] = MP_OBJ_TO_PTR(desc_uuid_obj);
                descriptor_flags[descriptor_index] = mp_obj_get_int(descriptor_items[1]);
                ++descriptor_index;

                (*handles)[handle_index++] = 0xffff;
            }

            // Reflect that we've grown the handles array.
            *num_handles += num_descriptors[characteristic_index];
        }

        characteristic_uuids[characteristic_index] = MP_OBJ_TO_PTR(uuid_obj);
        characteristic_flags[characteristic_index] = mp_obj_get_int(characteristic_items[1]);
        ++characteristic_index;
    }

    // Add service.
    return mp_bluetooth_gatts_register_service(service_uuid, characteristic_uuids, characteristic_flags, descriptor_uuids, descriptor_flags, num_descriptors, *handles, len);
}

STATIC mp_obj_t bluetooth_ble_gatts_register_services(mp_obj_t self_in, mp_obj_t services_in) {
    (void)self_in;
    mp_obj_t len_in = mp_obj_len(services_in);
    size_t len = mp_obj_get_int(len_in);
    mp_obj_iter_buf_t iter_buf;
    mp_obj_t iterable = mp_getiter(services_in, &iter_buf);
    mp_obj_t service_tuple_obj;

    mp_obj_tuple_t *result = MP_OBJ_TO_PTR(mp_obj_new_tuple(len, NULL));

    uint16_t **handles = m_new0(uint16_t *, len);
    size_t *num_handles = m_new0(size_t, len);

    // TODO: Add a `append` kwarg (defaulting to False) to make this behavior optional.
    bool append = false;
    int err = mp_bluetooth_gatts_register_service_begin(append);
    if (err != 0) {
        return bluetooth_handle_errno(err);
    }

    size_t i = 0;
    while ((service_tuple_obj = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
        // (uuid, chars)
        mp_obj_t *service_items;
        mp_obj_get_array_fixed_n(service_tuple_obj, 2, &service_items);
        err = bluetooth_gatts_register_service(service_items[0], service_items[1], &handles[i], &num_handles[i]);
        if (err != 0) {
            return bluetooth_handle_errno(err);
        }

        ++i;
    }

    // On Nimble, this will actually perform the registration, making the handles valid.
    err = mp_bluetooth_gatts_register_service_end();
    if (err != 0) {
        return bluetooth_handle_errno(err);
    }

    // Return tuple of tuple of value handles.
    // TODO: Also the Generic Access service characteristics?
    for (i = 0; i < len; ++i) {
        mp_obj_tuple_t *service_handles = MP_OBJ_TO_PTR(mp_obj_new_tuple(num_handles[i], NULL));
        for (size_t j = 0; j < num_handles[i]; ++j) {
            service_handles->items[j] = MP_OBJ_NEW_SMALL_INT(handles[i][j]);
        }
        result->items[i] = MP_OBJ_FROM_PTR(service_handles);
    }
    return MP_OBJ_FROM_PTR(result);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_gatts_register_services_obj, bluetooth_ble_gatts_register_services);

#if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
STATIC mp_obj_t bluetooth_ble_gap_connect(size_t n_args, const mp_obj_t *args) {
    uint8_t addr_type = mp_obj_get_int(args[1]);
    mp_buffer_info_t bufinfo = {0};
    mp_get_buffer_raise(args[2], &bufinfo, MP_BUFFER_READ);
    if (bufinfo.len != 6) {
        mp_raise_ValueError(MP_ERROR_TEXT("invalid addr"));
    }
    mp_int_t scan_duration_ms = MP_BLUETOOTH_CONNECT_DEFAULT_SCAN_DURATION_MS;
    if (n_args == 4) {
        scan_duration_ms = mp_obj_get_int(args[3]);
    }

    int err = mp_bluetooth_gap_peripheral_connect(addr_type, bufinfo.buf, scan_duration_ms);
    return bluetooth_handle_errno(err);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gap_connect_obj, 3, 4, bluetooth_ble_gap_connect);

STATIC mp_obj_t bluetooth_ble_gap_scan(size_t n_args, const mp_obj_t *args) {
    // Default is indefinite scan, with the NimBLE "background scan" interval and window.
    mp_int_t duration_ms = 0;
    mp_int_t interval_us = 1280000;
    mp_int_t window_us = 11250;
    bool active_scan = false;
    if (n_args > 1) {
        if (args[1] == mp_const_none) {
            // scan(None) --> stop scan.
            return bluetooth_handle_errno(mp_bluetooth_gap_scan_stop());
        }
        duration_ms = mp_obj_get_int(args[1]);
        if (n_args > 2) {
            interval_us = mp_obj_get_int(args[2]);
            if (n_args > 3) {
                window_us = mp_obj_get_int(args[3]);
                if (n_args > 4) {
                    active_scan = mp_obj_is_true(args[4]);
                }
            }
        }
    }
    return bluetooth_handle_errno(mp_bluetooth_gap_scan_start(duration_ms, interval_us, window_us, active_scan));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gap_scan_obj, 1, 5, bluetooth_ble_gap_scan);
#endif // MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE

STATIC mp_obj_t bluetooth_ble_gap_disconnect(mp_obj_t self_in, mp_obj_t conn_handle_in) {
    (void)self_in;
    uint16_t conn_handle = mp_obj_get_int(conn_handle_in);
    int err = mp_bluetooth_gap_disconnect(conn_handle);
    if (err == 0) {
        return mp_const_true;
    } else if (err == MP_ENOTCONN) {
        return mp_const_false;
    } else {
        return bluetooth_handle_errno(err);
    }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_gap_disconnect_obj, bluetooth_ble_gap_disconnect);

// ----------------------------------------------------------------------------
// Bluetooth object: GATTS (Peripheral/Advertiser role)
// ----------------------------------------------------------------------------

STATIC mp_obj_t bluetooth_ble_gatts_read(mp_obj_t self_in, mp_obj_t value_handle_in) {
    (void)self_in;
    size_t len = 0;
    uint8_t *buf;
    mp_bluetooth_gatts_read(mp_obj_get_int(value_handle_in), &buf, &len);
    return mp_obj_new_bytes(buf, len);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_gatts_read_obj, bluetooth_ble_gatts_read);

STATIC mp_obj_t bluetooth_ble_gatts_write(mp_obj_t self_in, mp_obj_t value_handle_in, mp_obj_t data) {
    (void)self_in;
    mp_buffer_info_t bufinfo = {0};
    mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
    int err = mp_bluetooth_gatts_write(mp_obj_get_int(value_handle_in), bufinfo.buf, bufinfo.len);
    bluetooth_handle_errno(err);
    return MP_OBJ_NEW_SMALL_INT(bufinfo.len);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(bluetooth_ble_gatts_write_obj, bluetooth_ble_gatts_write);

STATIC mp_obj_t bluetooth_ble_gatts_notify(size_t n_args, const mp_obj_t *args) {
    mp_int_t conn_handle = mp_obj_get_int(args[1]);
    mp_int_t value_handle = mp_obj_get_int(args[2]);

    if (n_args == 4 && args[3] != mp_const_none) {
        mp_buffer_info_t bufinfo = {0};
        mp_get_buffer_raise(args[3], &bufinfo, MP_BUFFER_READ);
        int err = mp_bluetooth_gatts_notify_send(conn_handle, value_handle, bufinfo.buf, bufinfo.len);
        bluetooth_handle_errno(err);
        return mp_const_none;
    } else {
        int err = mp_bluetooth_gatts_notify(conn_handle, value_handle);
        return bluetooth_handle_errno(err);
    }
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gatts_notify_obj, 3, 4, bluetooth_ble_gatts_notify);

STATIC mp_obj_t bluetooth_ble_gatts_indicate(mp_obj_t self_in, mp_obj_t conn_handle_in, mp_obj_t value_handle_in) {
    (void)self_in;
    mp_int_t conn_handle = mp_obj_get_int(conn_handle_in);
    mp_int_t value_handle = mp_obj_get_int(value_handle_in);

    int err = mp_bluetooth_gatts_indicate(conn_handle, value_handle);
    return bluetooth_handle_errno(err);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(bluetooth_ble_gatts_indicate_obj, bluetooth_ble_gatts_indicate);

STATIC mp_obj_t bluetooth_ble_gatts_set_buffer(size_t n_args, const mp_obj_t *args) {
    mp_int_t value_handle = mp_obj_get_int(args[1]);
    mp_int_t len = mp_obj_get_int(args[2]);
    bool append = n_args >= 4 && mp_obj_is_true(args[3]);
    return bluetooth_handle_errno(mp_bluetooth_gatts_set_buffer(value_handle, len, append));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gatts_set_buffer_obj, 3, 4, bluetooth_ble_gatts_set_buffer);

// ----------------------------------------------------------------------------
// Bluetooth object: GATTC (Central/Scanner role)
// ----------------------------------------------------------------------------

#if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE

STATIC mp_obj_t bluetooth_ble_gattc_discover_services(size_t n_args, const mp_obj_t *args) {
    mp_int_t conn_handle = mp_obj_get_int(args[1]);
    mp_obj_bluetooth_uuid_t *uuid = NULL;
    if (n_args == 3 && args[2] != mp_const_none) {
        if (!mp_obj_is_type(args[2], &bluetooth_uuid_type)) {
            mp_raise_TypeError(MP_ERROR_TEXT("UUID"));
        }
        uuid = MP_OBJ_TO_PTR(args[2]);
    }
    return bluetooth_handle_errno(mp_bluetooth_gattc_discover_primary_services(conn_handle, uuid));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gattc_discover_services_obj, 2, 3, bluetooth_ble_gattc_discover_services);

STATIC mp_obj_t bluetooth_ble_gattc_discover_characteristics(size_t n_args, const mp_obj_t *args) {
    mp_int_t conn_handle = mp_obj_get_int(args[1]);
    mp_int_t start_handle = mp_obj_get_int(args[2]);
    mp_int_t end_handle = mp_obj_get_int(args[3]);
    mp_obj_bluetooth_uuid_t *uuid = NULL;
    if (n_args == 5 && args[4] != mp_const_none) {
        if (!mp_obj_is_type(args[4], &bluetooth_uuid_type)) {
            mp_raise_TypeError(MP_ERROR_TEXT("UUID"));
        }
        uuid = MP_OBJ_TO_PTR(args[4]);
    }
    return bluetooth_handle_errno(mp_bluetooth_gattc_discover_characteristics(conn_handle, start_handle, end_handle, uuid));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gattc_discover_characteristics_obj, 4, 5, bluetooth_ble_gattc_discover_characteristics);

STATIC mp_obj_t bluetooth_ble_gattc_discover_descriptors(size_t n_args, const mp_obj_t *args) {
    (void)n_args;
    mp_int_t conn_handle = mp_obj_get_int(args[1]);
    mp_int_t start_handle = mp_obj_get_int(args[2]);
    mp_int_t end_handle = mp_obj_get_int(args[3]);
    return bluetooth_handle_errno(mp_bluetooth_gattc_discover_descriptors(conn_handle, start_handle, end_handle));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gattc_discover_descriptors_obj, 4, 4, bluetooth_ble_gattc_discover_descriptors);

STATIC mp_obj_t bluetooth_ble_gattc_read(mp_obj_t self_in, mp_obj_t conn_handle_in, mp_obj_t value_handle_in) {
    (void)self_in;
    mp_int_t conn_handle = mp_obj_get_int(conn_handle_in);
    mp_int_t value_handle = mp_obj_get_int(value_handle_in);
    return bluetooth_handle_errno(mp_bluetooth_gattc_read(conn_handle, value_handle));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_3(bluetooth_ble_gattc_read_obj, bluetooth_ble_gattc_read);

STATIC mp_obj_t bluetooth_ble_gattc_write(size_t n_args, const mp_obj_t *args) {
    mp_int_t conn_handle = mp_obj_get_int(args[1]);
    mp_int_t value_handle = mp_obj_get_int(args[2]);
    mp_obj_t data = args[3];
    mp_buffer_info_t bufinfo = {0};
    mp_get_buffer_raise(data, &bufinfo, MP_BUFFER_READ);
    size_t len = bufinfo.len;
    unsigned int mode = MP_BLUETOOTH_WRITE_MODE_NO_RESPONSE;
    if (n_args == 5) {
        mode = mp_obj_get_int(args[4]);
    }
    return bluetooth_handle_errno(mp_bluetooth_gattc_write(conn_handle, value_handle, bufinfo.buf, &len, mode));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(bluetooth_ble_gattc_write_obj, 4, 5, bluetooth_ble_gattc_write);

STATIC mp_obj_t bluetooth_ble_gattc_exchange_mtu(mp_obj_t self_in, mp_obj_t conn_handle_in) {
    (void)self_in;
    uint16_t conn_handle = mp_obj_get_int(conn_handle_in);
    return bluetooth_handle_errno(mp_bluetooth_gattc_exchange_mtu(conn_handle));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_2(bluetooth_ble_gattc_exchange_mtu_obj, bluetooth_ble_gattc_exchange_mtu);

#endif // MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE

// ----------------------------------------------------------------------------
// Bluetooth object: Definition
// ----------------------------------------------------------------------------

STATIC const mp_rom_map_elem_t bluetooth_ble_locals_dict_table[] = {
    // General
    { MP_ROM_QSTR(MP_QSTR_active), MP_ROM_PTR(&bluetooth_ble_active_obj) },
    { MP_ROM_QSTR(MP_QSTR_config), MP_ROM_PTR(&bluetooth_ble_config_obj) },
    { MP_ROM_QSTR(MP_QSTR_irq), MP_ROM_PTR(&bluetooth_ble_irq_obj) },
    // GAP
    { MP_ROM_QSTR(MP_QSTR_gap_advertise), MP_ROM_PTR(&bluetooth_ble_gap_advertise_obj) },
    #if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
    { MP_ROM_QSTR(MP_QSTR_gap_connect), MP_ROM_PTR(&bluetooth_ble_gap_connect_obj) },
    { MP_ROM_QSTR(MP_QSTR_gap_scan), MP_ROM_PTR(&bluetooth_ble_gap_scan_obj) },
    #endif
    { MP_ROM_QSTR(MP_QSTR_gap_disconnect), MP_ROM_PTR(&bluetooth_ble_gap_disconnect_obj) },
    // GATT Server (i.e. peripheral/advertiser role)
    { MP_ROM_QSTR(MP_QSTR_gatts_register_services), MP_ROM_PTR(&bluetooth_ble_gatts_register_services_obj) },
    { MP_ROM_QSTR(MP_QSTR_gatts_read), MP_ROM_PTR(&bluetooth_ble_gatts_read_obj) },
    { MP_ROM_QSTR(MP_QSTR_gatts_write), MP_ROM_PTR(&bluetooth_ble_gatts_write_obj) },
    { MP_ROM_QSTR(MP_QSTR_gatts_notify), MP_ROM_PTR(&bluetooth_ble_gatts_notify_obj) },
    { MP_ROM_QSTR(MP_QSTR_gatts_indicate), MP_ROM_PTR(&bluetooth_ble_gatts_indicate_obj) },
    { MP_ROM_QSTR(MP_QSTR_gatts_set_buffer), MP_ROM_PTR(&bluetooth_ble_gatts_set_buffer_obj) },
    #if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
    // GATT Client (i.e. central/scanner role)
    { MP_ROM_QSTR(MP_QSTR_gattc_discover_services), MP_ROM_PTR(&bluetooth_ble_gattc_discover_services_obj) },
    { MP_ROM_QSTR(MP_QSTR_gattc_discover_characteristics), MP_ROM_PTR(&bluetooth_ble_gattc_discover_characteristics_obj) },
    { MP_ROM_QSTR(MP_QSTR_gattc_discover_descriptors), MP_ROM_PTR(&bluetooth_ble_gattc_discover_descriptors_obj) },
    { MP_ROM_QSTR(MP_QSTR_gattc_read), MP_ROM_PTR(&bluetooth_ble_gattc_read_obj) },
    { MP_ROM_QSTR(MP_QSTR_gattc_write), MP_ROM_PTR(&bluetooth_ble_gattc_write_obj) },
    { MP_ROM_QSTR(MP_QSTR_gattc_exchange_mtu), MP_ROM_PTR(&bluetooth_ble_gattc_exchange_mtu_obj) },
    #endif
};
STATIC MP_DEFINE_CONST_DICT(bluetooth_ble_locals_dict, bluetooth_ble_locals_dict_table);

STATIC const mp_obj_type_t bluetooth_ble_type = {
    { &mp_type_type },
    .name = MP_QSTR_BLE,
    .make_new = bluetooth_ble_make_new,
    .locals_dict = (void *)&bluetooth_ble_locals_dict,
};

STATIC const mp_rom_map_elem_t mp_module_bluetooth_globals_table[] = {
    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_ubluetooth) },
    { MP_ROM_QSTR(MP_QSTR_BLE), MP_ROM_PTR(&bluetooth_ble_type) },
    { MP_ROM_QSTR(MP_QSTR_UUID), MP_ROM_PTR(&bluetooth_uuid_type) },
    { MP_ROM_QSTR(MP_QSTR_FLAG_READ), MP_ROM_INT(MP_BLUETOOTH_CHARACTERISTIC_FLAG_READ) },
    { MP_ROM_QSTR(MP_QSTR_FLAG_WRITE), MP_ROM_INT(MP_BLUETOOTH_CHARACTERISTIC_FLAG_WRITE) },
    { MP_ROM_QSTR(MP_QSTR_FLAG_NOTIFY), MP_ROM_INT(MP_BLUETOOTH_CHARACTERISTIC_FLAG_NOTIFY) },
    { MP_ROM_QSTR(MP_QSTR_FLAG_INDICATE), MP_ROM_INT(MP_BLUETOOTH_CHARACTERISTIC_FLAG_INDICATE) },
    { MP_ROM_QSTR(MP_QSTR_FLAG_WRITE_NO_RESPONSE), MP_ROM_INT(MP_BLUETOOTH_CHARACTERISTIC_FLAG_WRITE_NO_RESPONSE) },
};

STATIC MP_DEFINE_CONST_DICT(mp_module_bluetooth_globals, mp_module_bluetooth_globals_table);

const mp_obj_module_t mp_module_ubluetooth = {
    .base = { &mp_type_module },
    .globals = (mp_obj_dict_t *)&mp_module_bluetooth_globals,
};

// Helpers

#include <stdio.h>

STATIC void ringbuf_extract(ringbuf_t *ringbuf, mp_obj_tuple_t *data_tuple, size_t n_u16, size_t n_u8, mp_obj_str_t *bytes_addr, size_t n_i8, mp_obj_bluetooth_uuid_t *uuid, mp_obj_str_t *bytes_data) {
    assert(ringbuf_avail(ringbuf) >= n_u16 * 2 + n_u8 + (bytes_addr ? 6 : 0) + n_i8 + (uuid ? 1 : 0) + (bytes_data ? 1 : 0));
    size_t j = 0;

    for (size_t i = 0; i < n_u16; ++i) {
        data_tuple->items[j++] = MP_OBJ_NEW_SMALL_INT(ringbuf_get16(ringbuf));
    }
    if (n_u8) {
        data_tuple->items[j++] = MP_OBJ_NEW_SMALL_INT(ringbuf_get(ringbuf));
    }
    if (bytes_addr) {
        bytes_addr->len = 6;
        for (size_t i = 0; i < bytes_addr->len; ++i) {
            // cast away const, this is actually bt->irq_addr_bytes.
            ((uint8_t *)bytes_addr->data)[i] = ringbuf_get(ringbuf);
        }
        data_tuple->items[j++] = MP_OBJ_FROM_PTR(bytes_addr);
    }
    for (size_t i = 0; i < n_i8; ++i) {
        // Note the int8_t got packed into the ringbuf as a uint8_t.
        data_tuple->items[j++] = MP_OBJ_NEW_SMALL_INT((int8_t)ringbuf_get(ringbuf));
    }
    #if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
    if (uuid) {
        ringbuf_get_uuid(ringbuf, uuid);
        data_tuple->items[j++] = MP_OBJ_FROM_PTR(uuid);
    }
    #endif
    // The code that enqueues into the ringbuf should ensure that it doesn't
    // put more than bt->irq_data_data_alloc bytes into the ringbuf, because
    // that's what's available here in bt->irq_data_bytes.
    if (bytes_data) {
        bytes_data->len = ringbuf_get16(ringbuf);
        for (size_t i = 0; i < bytes_data->len; ++i) {
            // cast away const, this is actually bt->irq_data_bytes.
            ((uint8_t *)bytes_data->data)[i] = ringbuf_get(ringbuf);
        }
        data_tuple->items[j++] = MP_OBJ_FROM_PTR(bytes_data);
    }

    data_tuple->len = j;
}

STATIC mp_obj_t bluetooth_ble_invoke_irq(mp_obj_t none_in) {
    (void)none_in;
    // This is always executing in schedule context.

    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    o->irq_scheduled = false;

    for (;;) {
        MICROPY_PY_BLUETOOTH_ENTER

        mp_int_t event = ringbuf_get(&o->ringbuf);
        if (event < 0) {
            // Nothing available in ringbuf.
            MICROPY_PY_BLUETOOTH_EXIT
            break;
        }

        // Although we're in schedule context, this code still avoids using any allocations:
        //  - IRQs are disabled (to protect the ringbuf), and we need to avoid triggering GC
        //  - The user's handler might not alloc, so we shouldn't either.

        mp_obj_t handler = handler = o->irq_handler;
        mp_obj_tuple_t *data_tuple = MP_OBJ_TO_PTR(o->irq_data_tuple);

        if (event == MP_BLUETOOTH_IRQ_CENTRAL_CONNECT || event == MP_BLUETOOTH_IRQ_PERIPHERAL_CONNECT || event == MP_BLUETOOTH_IRQ_CENTRAL_DISCONNECT || event == MP_BLUETOOTH_IRQ_PERIPHERAL_DISCONNECT) {
            // conn_handle, addr_type, addr
            ringbuf_extract(&o->ringbuf, data_tuple, 1, 1, &o->irq_data_addr, 0, NULL, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_GATTS_WRITE) {
            // conn_handle, value_handle
            ringbuf_extract(&o->ringbuf, data_tuple, 2, 0, NULL, 0, NULL, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_GATTS_INDICATE_DONE) {
            // conn_handle, value_handle, status
            ringbuf_extract(&o->ringbuf, data_tuple, 2, 1, NULL, 0, NULL, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_MTU_EXCHANGED) {
            // conn_handle, mtu
            ringbuf_extract(&o->ringbuf, data_tuple, 2, 0, NULL, 0, NULL, NULL);
        #if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
        } else if (event == MP_BLUETOOTH_IRQ_SCAN_RESULT) {
            // addr_type, addr, adv_type, rssi, adv_data
            ringbuf_extract(&o->ringbuf, data_tuple, 0, 1, &o->irq_data_addr, 2, NULL, &o->irq_data_data);
        } else if (event == MP_BLUETOOTH_IRQ_SCAN_DONE) {
            // No params required.
            data_tuple->len = 0;
        } else if (event == MP_BLUETOOTH_IRQ_GATTC_SERVICE_RESULT) {
            // conn_handle, start_handle, end_handle, uuid
            ringbuf_extract(&o->ringbuf, data_tuple, 3, 0, NULL, 0, &o->irq_data_uuid, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_GATTC_CHARACTERISTIC_RESULT) {
            // conn_handle, def_handle, value_handle, properties, uuid
            ringbuf_extract(&o->ringbuf, data_tuple, 3, 1, NULL, 0, &o->irq_data_uuid, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_GATTC_DESCRIPTOR_RESULT) {
            // conn_handle, handle, uuid
            ringbuf_extract(&o->ringbuf, data_tuple, 2, 0, NULL, 0, &o->irq_data_uuid, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_GATTC_SERVICE_DONE || event == MP_BLUETOOTH_IRQ_GATTC_CHARACTERISTIC_DONE || event == MP_BLUETOOTH_IRQ_GATTC_DESCRIPTOR_DONE) {
            // conn_handle, status
            ringbuf_extract(&o->ringbuf, data_tuple, 2, 0, NULL, 0, NULL, NULL);
        } else if (event == MP_BLUETOOTH_IRQ_GATTC_READ_RESULT || event == MP_BLUETOOTH_IRQ_GATTC_NOTIFY || event == MP_BLUETOOTH_IRQ_GATTC_INDICATE) {
            // conn_handle, value_handle, data
            ringbuf_extract(&o->ringbuf, data_tuple, 2, 0, NULL, 0, NULL, &o->irq_data_data);
        } else if (event == MP_BLUETOOTH_IRQ_GATTC_READ_DONE || event == MP_BLUETOOTH_IRQ_GATTC_WRITE_DONE) {
            // conn_handle, value_handle, status
            ringbuf_extract(&o->ringbuf, data_tuple, 3, 0, NULL, 0, NULL, NULL);
        #endif // MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
        }

        MICROPY_PY_BLUETOOTH_EXIT

        mp_call_function_2(handler, MP_OBJ_NEW_SMALL_INT(event), MP_OBJ_FROM_PTR(data_tuple));
    }

    return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(bluetooth_ble_invoke_irq_obj, bluetooth_ble_invoke_irq);

// ----------------------------------------------------------------------------
// Port API
// ----------------------------------------------------------------------------

// Callbacks are called in interrupt context (i.e. can't allocate), so we need to push the data
// into the ringbuf and schedule the callback via mp_sched_schedule.

STATIC bool enqueue_irq(mp_obj_bluetooth_ble_t *o, size_t len, uint8_t event) {
    if (!o || o->irq_handler == mp_const_none) {
        return false;
    }

    // Check if there is enough room for <event-type><payload>.
    if (ringbuf_free(&o->ringbuf) < len + 1) {
        // Ringbuffer doesn't have room (and is therefore non-empty).

        // If this is another scan result, or the front of the ringbuffer isn't a scan result, then nothing to do.
        if (event == MP_BLUETOOTH_IRQ_SCAN_RESULT || ringbuf_peek(&o->ringbuf) != MP_BLUETOOTH_IRQ_SCAN_RESULT) {
            return false;
        }

        // Front of the queue is a scan result, remove it.

        // event, addr_type, addr, adv_type, rssi
        int n = 1 + 1 + 6 + 1 + 1;
        for (int i = 0; i < n; ++i) {
            ringbuf_get(&o->ringbuf);
        }
        // adv_data
        n = ringbuf_get(&o->ringbuf);
        for (int i = 0; i < n; ++i) {
            ringbuf_get(&o->ringbuf);
        }
    }

    // Append this event, the caller will then append the arguments.
    ringbuf_put(&o->ringbuf, event);
    return true;
}

// Must hold the atomic section before calling this (MICROPY_PY_BLUETOOTH_ENTER).
STATIC void schedule_ringbuf(mp_uint_t atomic_state) {
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (!o->irq_scheduled) {
        o->irq_scheduled = true;
        MICROPY_PY_BLUETOOTH_EXIT
        mp_sched_schedule(MP_OBJ_FROM_PTR(&bluetooth_ble_invoke_irq_obj), mp_const_none);
    } else {
        MICROPY_PY_BLUETOOTH_EXIT
    }
}

void mp_bluetooth_gap_on_connected_disconnected(uint8_t event, uint16_t conn_handle, uint8_t addr_type, const uint8_t *addr) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 1 + 6, event)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put(&o->ringbuf, addr_type);
        for (int i = 0; i < 6; ++i) {
            ringbuf_put(&o->ringbuf, addr[i]);
        }
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gatts_on_write(uint16_t conn_handle, uint16_t value_handle) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2, MP_BLUETOOTH_IRQ_GATTS_WRITE)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, value_handle);
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gatts_on_indicate_complete(uint16_t conn_handle, uint16_t value_handle, uint8_t status) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2 + 1, MP_BLUETOOTH_IRQ_GATTS_INDICATE_DONE)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, value_handle);
        ringbuf_put(&o->ringbuf, status);
    }
    schedule_ringbuf(atomic_state);
}

#if MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE
void mp_bluetooth_gap_on_scan_complete(void) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 0, MP_BLUETOOTH_IRQ_SCAN_DONE)) {
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gap_on_scan_result(uint8_t addr_type, const uint8_t *addr, uint8_t adv_type, const int8_t rssi, const uint8_t *data, size_t data_len) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    data_len = MIN(o->irq_data_data_alloc, data_len);
    if (enqueue_irq(o, 1 + 6 + 1 + 1 + 2 + data_len, MP_BLUETOOTH_IRQ_SCAN_RESULT)) {
        ringbuf_put(&o->ringbuf, addr_type);
        for (int i = 0; i < 6; ++i) {
            ringbuf_put(&o->ringbuf, addr[i]);
        }
        // The adv_type will get extracted as an int8_t but that's ok because valid values are 0x00-0x04.
        ringbuf_put(&o->ringbuf, adv_type);
        // Note conversion of int8_t rssi to uint8_t. Must un-convert on the way out.
        ringbuf_put(&o->ringbuf, (uint8_t)rssi);
        // Length field is 16-bit.
        data_len = MIN(UINT16_MAX, data_len);
        ringbuf_put16(&o->ringbuf, data_len);
        for (size_t i = 0; i < data_len; ++i) {
            ringbuf_put(&o->ringbuf, data[i]);
        }
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gattc_on_primary_service_result(uint16_t conn_handle, uint16_t start_handle, uint16_t end_handle, mp_obj_bluetooth_uuid_t *service_uuid) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2 + 2 + 1 + service_uuid->type, MP_BLUETOOTH_IRQ_GATTC_SERVICE_RESULT)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, start_handle);
        ringbuf_put16(&o->ringbuf, end_handle);
        ringbuf_put_uuid(&o->ringbuf, service_uuid);
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gattc_on_characteristic_result(uint16_t conn_handle, uint16_t def_handle, uint16_t value_handle, uint8_t properties, mp_obj_bluetooth_uuid_t *characteristic_uuid) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2 + 2 + 1 + characteristic_uuid->type, MP_BLUETOOTH_IRQ_GATTC_CHARACTERISTIC_RESULT)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, def_handle);
        ringbuf_put16(&o->ringbuf, value_handle);
        ringbuf_put(&o->ringbuf, properties);
        ringbuf_put_uuid(&o->ringbuf, characteristic_uuid);
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gattc_on_descriptor_result(uint16_t conn_handle, uint16_t handle, mp_obj_bluetooth_uuid_t *descriptor_uuid) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2 + 1 + descriptor_uuid->type, MP_BLUETOOTH_IRQ_GATTC_DESCRIPTOR_RESULT)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, handle);
        ringbuf_put_uuid(&o->ringbuf, descriptor_uuid);
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gattc_on_discover_complete(uint8_t event, uint16_t conn_handle, uint16_t status) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2, event)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, status);
    }
    schedule_ringbuf(atomic_state);
}

size_t mp_bluetooth_gattc_on_data_available_start(uint8_t event, uint16_t conn_handle, uint16_t value_handle, size_t data_len, mp_uint_t *atomic_state_out) {
    MICROPY_PY_BLUETOOTH_ENTER
    *atomic_state_out = atomic_state;
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    data_len = MIN(o->irq_data_data_alloc, data_len);
    if (enqueue_irq(o, 2 + 2 + 2 + data_len, event)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, value_handle);
        // Length field is 16-bit.
        data_len = MIN(UINT16_MAX, data_len);
        ringbuf_put16(&o->ringbuf, data_len);
        return data_len;
    } else {
        return 0;
    }
}

void mp_bluetooth_gattc_on_data_available_chunk(const uint8_t *data, size_t data_len) {
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    for (size_t i = 0; i < data_len; ++i) {
        ringbuf_put(&o->ringbuf, data[i]);
    }
}

void mp_bluetooth_gattc_on_data_available_end(mp_uint_t atomic_state) {
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gattc_on_read_write_status(uint8_t event, uint16_t conn_handle, uint16_t value_handle, uint16_t status) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2 + 2, event)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, value_handle);
        ringbuf_put16(&o->ringbuf, status);
    }
    schedule_ringbuf(atomic_state);
}

#endif // MICROPY_PY_BLUETOOTH_ENABLE_CENTRAL_MODE

#if MICROPY_PY_BLUETOOTH_GATTS_ON_READ_CALLBACK
// This can only be enabled when the thread invoking this is a MicroPython thread.
// On ESP32, for example, this is not the case.
bool mp_bluetooth_gatts_on_read_request(uint16_t conn_handle, uint16_t value_handle) {
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (o->irq_handler != mp_const_none) {
        // When executing code within a handler we must lock the scheduler to
        // prevent any scheduled callbacks from running, and lock the GC to
        // prevent any memory allocations.
        mp_sched_lock();
        gc_lock();

        // Use pre-allocated tuple distinct to the one used by the "soft" IRQs.
        mp_obj_tuple_t *data = MP_OBJ_TO_PTR(o->irq_read_request_data_tuple);
        data->items[0] = MP_OBJ_NEW_SMALL_INT(conn_handle);
        data->items[1] = MP_OBJ_NEW_SMALL_INT(value_handle);
        data->len = 2;
        mp_obj_t irq_ret = mp_call_function_2_protected(o->irq_handler, MP_OBJ_NEW_SMALL_INT(MP_BLUETOOTH_IRQ_GATTS_READ_REQUEST), o->irq_read_request_data_tuple);

        gc_unlock();
        mp_sched_unlock();

        // If the IRQ handler explicitly returned false, then deny the read. Otherwise if it returns None/True, allow it.
        return irq_ret != MP_OBJ_NULL && (irq_ret == mp_const_none || mp_obj_is_true(irq_ret));
    } else {
        // No IRQ handler, allow the read.
        return true;
    }
}
#endif

void mp_bluetooth_gatts_on_mtu_exchanged(uint16_t conn_handle, uint16_t value) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_obj_bluetooth_ble_t *o = MP_OBJ_TO_PTR(MP_STATE_VM(bluetooth));
    if (enqueue_irq(o, 2 + 2, MP_BLUETOOTH_IRQ_MTU_EXCHANGED)) {
        ringbuf_put16(&o->ringbuf, conn_handle);
        ringbuf_put16(&o->ringbuf, value);
    }
    schedule_ringbuf(atomic_state);
}

void mp_bluetooth_gatts_db_create_entry(mp_gatts_db_t db, uint16_t handle, size_t len) {
    mp_map_elem_t *elem = mp_map_lookup(db, MP_OBJ_NEW_SMALL_INT(handle), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND);
    mp_bluetooth_gatts_db_entry_t *entry = m_new(mp_bluetooth_gatts_db_entry_t, 1);
    entry->data = m_new(uint8_t, len);
    entry->data_alloc = len;
    entry->data_len = 0;
    entry->append = false;
    elem->value = MP_OBJ_FROM_PTR(entry);
}

mp_bluetooth_gatts_db_entry_t *mp_bluetooth_gatts_db_lookup(mp_gatts_db_t db, uint16_t handle) {
    mp_map_elem_t *elem = mp_map_lookup(db, MP_OBJ_NEW_SMALL_INT(handle), MP_MAP_LOOKUP);
    if (!elem) {
        return NULL;
    }
    return MP_OBJ_TO_PTR(elem->value);
}

int mp_bluetooth_gatts_db_read(mp_gatts_db_t db, uint16_t handle, uint8_t **value, size_t *value_len) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_bluetooth_gatts_db_entry_t *entry = mp_bluetooth_gatts_db_lookup(db, handle);
    if (entry) {
        *value = entry->data;
        *value_len = entry->data_len;
        if (entry->append) {
            entry->data_len = 0;
        }
    }
    MICROPY_PY_BLUETOOTH_EXIT
    return entry ? 0 : MP_EINVAL;
}

int mp_bluetooth_gatts_db_write(mp_gatts_db_t db, uint16_t handle, const uint8_t *value, size_t value_len) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_bluetooth_gatts_db_entry_t *entry = mp_bluetooth_gatts_db_lookup(db, handle);
    if (entry) {
        if (value_len > entry->data_alloc) {
            uint8_t *data = m_new_maybe(uint8_t, value_len);
            if (data) {
                entry->data = data;
                entry->data_alloc = value_len;
            } else {
                MICROPY_PY_BLUETOOTH_EXIT
                return MP_ENOMEM;
            }
        }

        memcpy(entry->data, value, value_len);
        entry->data_len = value_len;
    }
    MICROPY_PY_BLUETOOTH_EXIT
    return entry ? 0 : MP_EINVAL;
}

int mp_bluetooth_gatts_db_resize(mp_gatts_db_t db, uint16_t handle, size_t len, bool append) {
    MICROPY_PY_BLUETOOTH_ENTER
    mp_bluetooth_gatts_db_entry_t *entry = mp_bluetooth_gatts_db_lookup(db, handle);
    if (entry) {
        uint8_t *data = m_renew_maybe(uint8_t, entry->data, entry->data_alloc, len, true);
        if (data) {
            entry->data = data;
            entry->data_alloc = len;
            entry->data_len = 0;
            entry->append = append;
        } else {
            MICROPY_PY_BLUETOOTH_EXIT
            return MP_ENOMEM;
        }
    }
    MICROPY_PY_BLUETOOTH_EXIT
    return entry ? 0 : MP_EINVAL;
}

#endif // MICROPY_PY_BLUETOOTH