#include <string.h>
#include <math.h>

#include "hardware/pwm.h"
#include "hardware/watchdog.h"

#include "badger2040.hpp"

namespace pimoroni {

  void Badger2040::init() {
    // set clock speed to 12MHz to reduce the maximum current draw on the
    // battery. when updating a small, monochrome, display only every few
    // seconds or so then you don't need much processing power anyway...
    //set_sys_clock_khz(48000, true);

    gpio_set_function(ENABLE_3V3, GPIO_FUNC_SIO);
    gpio_set_dir(ENABLE_3V3, GPIO_OUT);
    gpio_put(ENABLE_3V3, 1);

    gpio_set_function(A, GPIO_FUNC_SIO);
    gpio_set_dir(A, GPIO_IN);
    gpio_set_pulls(A, false, true);

    gpio_set_function(B, GPIO_FUNC_SIO);
    gpio_set_dir(B, GPIO_IN);
    gpio_set_pulls(B, false, true);

    gpio_set_function(C, GPIO_FUNC_SIO);
    gpio_set_dir(C, GPIO_IN);
    gpio_set_pulls(C, false, true);

    gpio_set_function(D, GPIO_FUNC_SIO);
    gpio_set_dir(D, GPIO_IN);
    gpio_set_pulls(D, false, true);

    gpio_set_function(E, GPIO_FUNC_SIO);
    gpio_set_dir(E, GPIO_IN);
    gpio_set_pulls(E, false, true);

    gpio_set_function(USER, GPIO_FUNC_SIO);
    gpio_set_dir(USER, GPIO_IN);
    gpio_set_pulls(USER, true, false);

    gpio_set_function(VBUS_DETECT, GPIO_FUNC_SIO);
    gpio_set_dir(VBUS_DETECT, GPIO_IN);
    gpio_put(VBUS_DETECT, 1);

    // read initial button states
    uint32_t mask = (1UL << A) | (1UL << B) | (1UL << C) | (1UL << D) | (1UL << E);
    _wake_button_states |= gpio_get_all() & mask;

/*
    // wait for button to be released before continuing
    while(gpio_get_all() & mask) {
      tight_loop_contents();
    }
*/

    // led control pin
    pwm_config cfg = pwm_get_default_config();
    pwm_set_wrap(pwm_gpio_to_slice_num(LED), 65535);
    pwm_init(pwm_gpio_to_slice_num(LED), &cfg, true);
    gpio_set_function(LED, GPIO_FUNC_PWM);
    led(0);

    uc8151.init();

    // TODO: set default image?
  }

  void Badger2040::halt() {
    gpio_put(ENABLE_3V3, 0);

    // If running on USB we will not actually power down, so emulate the behaviour
    // of battery powered badge by listening for a button press and then resetting
    // Note: Don't use wait_for_press as that waits for the button to be release and
    //       we want the reboot to complete before the button is released.
    update_button_states();
    while(_button_states == 0) {
      update_button_states();
    }
    watchdog_reboot(0, 0, 0);
  }

  uint8_t _dither_value(int32_t x, int32_t y, uint8_t p) {
    // ordered dither matrix used in 4-bit mode
    static uint8_t _odm[16] = {
      0,  8,  2, 10,
      12,  4, 14,  6,
      3, 11,  1,  9,
      15,  7, 13,  5
    };

    if (p == 0) {
      return 1;
    }
    if (p == 15) {
      return 0;
    }

    // calculate dither matrix offset
    uint32_t dmo = (x & 0b11) | ((y & 0b11) << 2);

    return p <= _odm[dmo] ? 1 : 0;
  }

  // Return dither values for an entire byte in the column
  uint8_t _dither_column_value(int32_t x, uint8_t p) {
    if (p == 0) {
      return 0xff;
    }
    if (p == 15) {
      return 0;
    }

    uint8_t val = 0;
    for (int32_t y = 0; y < 4; ++y) {
      val |= _dither_value(x, y, p) << (7 - y);
    }
    val |= val >> 4;
    return val;
  }


  void Badger2040::clear() {
    const uint32_t column_len = 128 / 8;
    const uint32_t buf_len = column_len * 296;
    uint8_t* buf = uc8151.get_frame_buffer();
    
    if (_pen == 0) {
      memset(buf, 0xff, buf_len);
    }
    else if (_pen == 15) {
      memset(buf, 0, buf_len);
    }
    else {
      for(uint32_t x = 0; x < 296; x++) {
        uint8_t val = _dither_column_value(x, _pen);
        memset(buf, val, column_len);
        buf += column_len;
      }
    }
  }

  void Badger2040::pixel(int32_t x, int32_t y) {
    if(_thickness == 1) {
      uc8151.pixel(x, y, _dither_value(x, y, _pen));
    }else{
      uint8_t ht = _thickness / 2;
      for(int sy = 0; sy < _thickness; sy++) {
        for(int sx = 0; sx < _thickness; sx++) {
          uc8151.pixel(x + sx - ht, y + sy - ht, _dither_value(x + sx - ht, y + sy - ht, _pen));
        }
      }
    }
  }

  // Display a portion of an image (icon sheet) at dx, dy
  void Badger2040::icon(const uint8_t *data, int sheet_width, int icon_size, int index, int dx, int dy) {
    image(data, sheet_width, icon_size * index, 0, icon_size, icon_size, dx, dy);
  }

  // Display an image that fills the screen (296*128)
  void Badger2040::image(const uint8_t* data) {
    uint8_t* ptr = uc8151.get_frame_buffer();
    
    for (uint32_t x = 0; x < 296; ++x) {
      // extract bitmask for this pixel
      uint32_t bm = 0b10000000 >> (x & 0b111);
      
      for (uint32_t y = 0; y < 128; y += 8) {
        uint8_t val = 0;
        for (uint32_t cy = 0; cy < 8; ++cy) {
          // work out byte offset in source data
          uint32_t o = ((y + cy) * (296 >> 3)) + (x >> 3);
          
          // Set bit in val if set in source data
          if (data[o] & bm) {
            val |= 0b10000000 >> cy;
          }
        }
        *ptr++ = val;
      }
    }
  }

  // Display an image smaller than the screen (sw*sh) at dx, dy
  void Badger2040::image(const uint8_t *data, int w, int h, int x, int y) {
    if (x == 0 && y == 0 && w == 296 && h == 128) {
      image(data);
    }
    else {
      image(data, w, 0, 0, w, h, x, y);
    }
  }

  void Badger2040::image(const uint8_t *data, int stride, int sx, int sy, int dw, int dh, int dx, int dy) {
    for(auto y = 0; y < dh; y++) {
      for(auto x = 0; x < dw; x++) {
        // work out byte offset in source data
        uint32_t o = ((y + sy) * (stride >> 3)) + ((x + sx) >> 3);

        // extract bitmask for this pixel
        uint32_t bm = 0b10000000 >> ((x + sx) & 0b111);

        // draw the pixel
        uc8151.pixel(dx + x, dy + y, data[o] & bm);
      }
    }
  }

  void Badger2040::rectangle(int32_t x, int32_t y, int32_t w, int32_t h) {
    // Adjust for thickness
    uint32_t ht = _thickness / 2;
    x -= ht;
    if (x < 0) {
      w += x;
      x = 0;
    }
    y -= ht;
    if (y < 0) {
      h += y;
      y = 0;
    }
    w += _thickness - 1;
    h += _thickness - 1;

    if (h >= 8) {
      // Directly write to the frame buffer when clearing a large area
      uint8_t* buf = uc8151.get_frame_buffer();
      
      for(int cx = x; cx < x + w; cx++) {
        uint8_t* buf_ptr = &buf[cx * 16 + y / 8];
        uint8_t first_mask = 0xff >> (y & 7);
        uint8_t last_mask = 0xff >> ((y + h) & 7);
        uint32_t val = _dither_column_value(cx, _pen);
        *buf_ptr &= ~first_mask;
        *buf_ptr++ |= (val & first_mask);
        for (int32_t c = h - (8 - (y & 7)); c >= 8; c -= 8) {
          *buf_ptr++ = val;
        }
        *buf_ptr &= last_mask;
        *buf_ptr |= (val & (~last_mask));
      }
    }
    else {
      for(int cx = x; cx < x + w; cx++) {
        for(int cy = y; cy < y + h; cy++) {
          uc8151.pixel(cx, cy, _dither_value(cx, cy, _pen));
        }
      }
    }
  }

  void Badger2040::line(int32_t x1, int32_t y1, int32_t x2, int32_t y2) {
    int32_t	x = x1, y = y1, dx, dy, incx, incy, balance;

    if(x2 >= x1) {dx = x2 - x1; incx = 1;} else {dx = x1 - x2; incx = -1;}
    if(y2 >= y1) {dy = y2 - y1; incy = 1;} else {dy = y1 - y2; incy = -1;}

    if(dx >= dy) {
      dy <<= 1; balance = dy - dx; dx <<= 1;
      while(x != x2) {
        pixel(x, y);
        if (balance >= 0) {y += incy; balance -= dx;}
        balance += dy; x += incx;
      }
    } else {
      dx <<= 1; balance = dx - dy; dy <<= 1;
      while(y != y2) {
        pixel(x, y);
        if(balance >= 0) {x += incx; balance -= dy;}
        balance += dx; y += incy;
      }
    }
  }

  void Badger2040::debug_command(uint8_t reg, size_t len, const uint8_t *data) {
    uc8151.command(reg, len, data);
  }

  void Badger2040::dump_otp(uint8_t *data) {
    uc8151.read(0xa2,  0xFFF, data);
  }

  void Badger2040::update_button_states() {
    uint32_t mask = (1UL << A) | (1UL << B) | (1UL << C) | (1UL << D) | (1UL << E) | (1UL << USER);
    _button_states = gpio_get_all() & mask;
    _button_states ^= (1UL << USER); // USER button state is inverted
  }

  uint32_t Badger2040::button_states() {
    return _button_states;
  }

  bool Badger2040::is_busy() {
    return uc8151.is_busy();
  }

  void Badger2040::power_off() {
    uc8151.power_off();
  }

  void Badger2040::invert(bool invert) {
    uc8151.invert(invert);
  }

  void Badger2040::update_speed(uint8_t speed) {
    uc8151.update_speed(speed);
  }

  uint32_t Badger2040::update_time() {
    return uc8151.update_time();
  }

  void Badger2040::partial_update(int x, int y, int w, int h, bool blocking) {
    uc8151.partial_update(x, y, w, h, blocking);
  }

  void Badger2040::update(bool blocking) {
    uc8151.update(blocking);
  }

  const hershey::font_glyph_t* Badger2040::glyph_data(unsigned char c) {
    return hershey::glyph_data(_font, c);
  }

  int32_t Badger2040::glyph(unsigned char c, int32_t x, int32_t y, float s, float a) {
    return hershey::glyph(_font, [this](int32_t x1, int32_t y1, int32_t x2, int32_t y2) {
      line(x1, y1, x2, y2);
    }, c, x, y, s, a);
  }

  void Badger2040::text(std::string message, int32_t x, int32_t y, float s, float a) {
    hershey::text(_font, [this](int32_t x1, int32_t y1, int32_t x2, int32_t y2) {
      line(x1, y1, x2, y2);
    }, message, x, y, s, a);
  }

  int32_t Badger2040::measure_text(std::string message, float s) {
    return hershey::measure_text(_font, message, s);
  }

  int32_t Badger2040::measure_glyph(unsigned char c, float s) {
    return hershey::measure_glyph(_font, c, s);
  }

  void Badger2040::font(std::string name) {
    // check that font exists and assign it
    if(hershey::fonts.find(name) != hershey::fonts.end()) {
      _font = hershey::fonts[name];
    }
  }

  void Badger2040::pen(uint8_t pen) {
    _pen = pen;
  }

  void Badger2040::thickness(uint8_t thickness) {
    _thickness = thickness;
  }

  void Badger2040::led(uint8_t brightness) {
    // set the led brightness from 1 to 256 with gamma correction
    float gamma = 2.8;
    uint16_t v = (uint16_t)(pow((float)(brightness) / 256.0f, gamma) * 65535.0f + 0.5f);
    pwm_set_gpio_level(LED, v);
  }

  bool Badger2040::pressed(uint8_t button) {
    return (_button_states & (1UL << button)) != 0;
  }

  bool Badger2040::pressed_to_wake(uint8_t button) {
    return (_wake_button_states & (1UL << button)) != 0;
  }

  void Badger2040::wait_for_press() {
    update_button_states();
    while(_button_states == 0) {
      update_button_states();
      tight_loop_contents();
    }

    uint32_t mask = (1UL << A) | (1UL << B) | (1UL << C) | (1UL << D) | (1UL << E);
    while(gpio_get_all() & mask) {
      tight_loop_contents();
    }
  }
}