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

#include "hardware/pwm.h"

#include "badger2040.hpp"

namespace pimoroni {

  Badger2040::Badger2040()
    : uc8151(296, 128, spi0, CS, DC, CLK, MOSI, BUSY, RESET) {
  }

  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_put(A, 1);

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

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

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

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

    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::clear() {
    for(uint32_t y = 0; y < 128; y++) {
      for(uint32_t x = 0; x < 296; x++) {
        pixel(x, y);
      }
    }
  }

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

    // don't allow any more code to execute while power rail drops
    while(true) {}
  }

  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
    };

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

    if(p == 0) {
      return 1;
    }else if(p == 15) {
      return 0;
    }else{
      return p <= _odm[dmo] ? 1 : 0;
    }
  }

  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));
        }
      }
    }
  }

  void Badger2040::rectangle(int32_t x, int32_t y, int32_t w, int32_t h) {
    for(int cy = y; cy < y + h; cy++) {
      for(int cx = x; cx < x + w; cx++) {
        pixel(cx, cy);
      }
    }
  }

  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::update_button_states() {
    uint32_t mask = (1UL << A) | (1UL << B) | (1UL << C) | (1UL << D) | (1UL << E);
    _button_states |= gpio_get_all() & mask;
  }

  void Badger2040::update() {
    // wait for display to not be busy
    while(uc8151.is_busy()) {
      tight_loop_contents();
    }

    uc8151.update(false);

    _button_states = 0;

    // wait for display to not be busy but sample buttons in case they are
    // pressed during this time
    while(uc8151.is_busy()) {
      update_button_states();
      tight_loop_contents();
    }

    uc8151.off();
  }

  const hershey_font_glyph_t* Badger2040::glyph_data(unsigned char c) {
    if(c < 32 || c > 127) {
      return nullptr;
    }

    return &_font->chars[c - 32];
  }

  int32_t Badger2040::glyph(unsigned char c, int32_t x, int32_t y, float s) {
    // if space character then return a width to move the caret by
    const hershey_font_glyph_t *gd = glyph_data(c);

    // if glyph data not found (id too great) then skip
    if(!gd) {
      return 0;
    }

    const int8_t *pv = gd->vertices;
    int8_t cx = (*pv++) * s;
    int8_t cy = (*pv++) * s;
    bool pen_down = true;

    for(uint32_t i = 1; i < gd->vertex_count; i++) {
      if(pv[0] == -128 && pv[1] == -128) {
        pen_down = false;
        pv += 2;
      }else{
        int8_t nx = (*pv++) * s;
        int8_t ny = (*pv++) * s;

        if(pen_down) {
          line(cx + x, cy + y, nx + x, ny + y);
        }

        cx = nx;
        cy = ny;
        pen_down = true;
      }
    }

    return gd->width * s;
  }

  void Badger2040::text(std::string message, int32_t x, int32_t y, float s) {
    int32_t cx = x;
    int32_t cy = y;

    for(auto &c : message) {
      cx += glyph(c, cx, cy, s);
    }
  }

  void Badger2040::font(std::string name) {
    // check that font exists and assign it
    if(fonts.find(name) != fonts.end()) {
      _font = 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() {
    while(_button_states == 0) {
      update_button_states();
      tight_loop_contents();
    }
  }
}