/* ----------------------------------------------------------------------------
 * main()
 * ----------------------------------------------------------------------------
 * Copyright (c) 2012 Ben Blazak <benblazak.dev@gmail.com>
 * Released under The MIT License (MIT) (see "license.md")
 * Project located at <https://github.com/benblazak/ergodox-firmware>
 * ------------------------------------------------------------------------- */

#include <stdbool.h>
#include <stdint.h>

// --------------------------------------------------------------------
// types and forward declarations
// --------------------------------------------------------------------

typedef int8_t  	i8;
typedef uint8_t 	u8;
typedef int16_t 	i16;
typedef uint16_t	u16;
typedef uint32_t	u32;

typedef u8 	keycode;
typedef u16	media_keycode;
typedef u8 	layer;
typedef u32	millis; // wraps every 50 days, but that's fine for our logic

typedef void (*keyfunc)(keycode, bool);

#include "./main.h"

// --------------------------------------------------------------------
// hardware
// --------------------------------------------------------------------

// comment out this define to disable the debug interface completely
// however, just not using the functions gets rid of most of the firmware bloat already
#define KBD_DEBUG
#include "./keyboard/controller.c"
#include "./keyboard/keyboard.h"

// ----------------------------------------------------------------------------
// layout data
// ----------------------------------------------------------------------------

#include "./keyboard/layout.c"
// defines:
// #define KB_LAYERS #{Layers.size}
// static const keycode	PROGMEM _kb_layout_code[KB_ROWS][KB_COLUMNS][KB_LAYERS];
// static const keyfunc	PROGMEM _kb_layout_func[KB_ROWS][KB_COLUMNS][KB_LAYERS];

/* static u8 layers[KB_LAYERS] = {0, 1, 1+2, 3, 4, 2+3+4}; */

#if KB_LAYERS > 8
#error "can only handle 8 layers for now"
#endif

// ----------------------------------------------------------------------------
// globals
// ----------------------------------------------------------------------------

static bool	_kb_is_pressed[KB_ROWS][KB_COLUMNS];
static bool	(*kb_is_pressed)[KB_ROWS][KB_COLUMNS] = &_kb_is_pressed;

static bool	_kb_was_pressed[KB_ROWS][KB_COLUMNS];
static bool	(*kb_was_pressed)[KB_ROWS][KB_COLUMNS] = &_kb_was_pressed;

static layer	layers_pressed[KB_ROWS][KB_COLUMNS];

static i8   	layers_active[KB_LAYERS];
static layer	layers_top;
static u8   	layers_state;

static bool	layer_sticky_on;
static bool	layer_sticky[KB_LAYERS];
static bool	layer_sticky_done;
static u8  	mod_sticky;
static bool	mod_sticky_done;

static millis	time_pressed[KB_ROWS][KB_COLUMNS];

// TODO this only exists as a workaround until we handle our own key repeats
static const keyfunc _kb_layer_funcs[] = {
  &kbfun_layer_press_release,
  &kbfun_layer_sticky,
  &kbfun_shift_layer_press_release,
  &kbfun_control_layer_press_release,
  &kbfun_alt_layer_press_release,
  &kbfun_win_layer_press_release,
};

// ----------------------------------------------------------------------------
// utilities
// ----------------------------------------------------------------------------

#define array_length(x) (sizeof(x) / sizeof((x)[0]))

#define set_bit(x, i)   	(x) |= (1u << (i))
#define unset_bit(x, i) 	(x) &= ~(1u << (i))
#define toggle_bit(x, i)	(x) ^= (1u << (i))
#define is_set(x, i)    	(((x) >> (i)) & 1u)
#define is_unset(x, i)  	!is_set((x), (i))

#define set_layer(x, layer)   	set_bit((x), (layer) - 1)
#define unset_layer(x, layer) 	unset_bit((x), (layer) - 1)
#define toggle_layer(x, layer)	toggle_bit((x), (layer) - 1)

millis now() { return timer0_ms; }

// ----------------------------------------------------------------------------
// main
// ----------------------------------------------------------------------------

int main() {
  // initialize
  init_hw();
  init_layers();
  init_sticky();
  init_timer();

  // never return
  main_key_loop();
  return 0;
}

void main_key_loop() {
  for (;;) {
    // swap `kb_is_pressed` and `kb_was_pressed`, then update
    bool (*temp)[KB_ROWS][KB_COLUMNS]	= kb_was_pressed;
    kb_was_pressed                   	= kb_is_pressed;
    kb_is_pressed                    	= temp;

    kb_update_matrix(*kb_is_pressed);

    // - execute key functions when their key changes state
    // - keep track of which layers the keys were on when they were pressed
    //   (so they can be released using the function from that layer)
    for (u8 row=0; row<KB_ROWS; row++) {
      for (u8 col=0; col<KB_COLUMNS; col++) {
        bool is_pressed 	= (*kb_is_pressed)[row][col];
        bool was_pressed	= (*kb_was_pressed)[row][col];

        if (is_pressed != was_pressed) {
          layer layer;
          if (is_pressed) {
            layer = layers_top;
            layers_pressed[row][col] = layer;

            if (!was_pressed) {
              time_pressed[row][col] = now();
            } else {
              // repeat
            }
          } else {
            layer = layers_pressed[row][col];
            layers_pressed[row][col] = 0;

            /* debug_printf("ms: %lu\n", now() - time_pressed[row][col]); */
          }

          // set remaining vars, and "execute" key
          exec_key(layer, row, col, is_pressed);
        }
      }
    }

    // send the USB report (even if nothing's changed)
    usb_keyboard_send();
    usb_extra_consumer_send();

    // unset sticky keys if necessary
    if (layer_sticky_on && layer_sticky_done) {
      for (layer l=1; l < KB_LAYERS; l++) {
        if (layer_sticky[l]) {
          layer_disable(l);
          layer_sticky[l] = false;
        }
      }
      layer_sticky_on  	= false;
      layer_sticky_done	= false;
    }

    if (mod_sticky && mod_sticky_done) {
      keyboard_modifier_keys &= ~mod_sticky;
      usb_keyboard_send();
      mod_sticky = 0;
      mod_sticky_done = false;
    }

    // debounce in ms; see keyswitch spec for necessary value
    _delay_ms(5);
  }
}

// ----------------------------------------------------------------------------
// init functions
// ----------------------------------------------------------------------------

void init_hw() {
  kb_init();
  usb_init();
  while (!usb_configured());
}

void init_sticky() {
  for (layer l=1; l < KB_LAYERS; l++) {
    layer_sticky[l] = false;
  }
  layer_sticky_on  	= false;
  mod_sticky       	= 0;
  layer_sticky_done	= false;
  mod_sticky_done  	= false;
}

void init_layers() {
  for (layer l=0; l < KB_LAYERS; l++) {
    layers_active[l] = 0;
  }
  layers_active[0]	= 1;
  layers_top      	= 0;
  layers_state    	= 1;

  for (u8 row=0; row<KB_ROWS; row++) {
    for (u8 col=0; col<KB_COLUMNS; col++) {
      layers_pressed[row][col] = 0;
    }
  }
}

void init_timer() {
  for (u8 row=0; row<KB_ROWS; row++) {
    for (u8 col=0; col<KB_COLUMNS; col++) {
      time_pressed[row][col] = 0;
    }
  }
}

// ----------------------------------------------------------------------------
// layer functions
// ----------------------------------------------------------------------------

// find highest active layer
layer highest_active_layer() {
  for (layer l = KB_LAYERS - 1; l > 0; l--) {
    if (layers_active[l] > 0) { return l; }
    /* if (is_set(layers_state, l)) { return l; } */
  }

  // the base layer is always active
  return 0;
}

// enable a layer
void layer_enable(layer l) {
  if (l >= KB_LAYERS || l == 0) { return; }

  layers_active[l] += 1;
  set_layer(layers_state, l);

  if (l > layers_top) {
    layers_top = l;
  }
}

// disable a layer
void layer_disable(layer l) {
  // base layer stays always on
  if (l >= KB_LAYERS || l == 0) { return; }

  if (layers_active[l] > 0) {
    layers_active[l] -= 1;
  }
  if (layers_active[l] == 0) {
    unset_layer(layers_state, l);
  }

  if (l == layers_top) {
    layers_top = highest_active_layer();
  }

  // re-press affected keys
  for (u8 row=0; row<KB_ROWS; row++) {
    for (u8 col=0; col<KB_COLUMNS; col++) {
      if (layers_pressed[row][col] == l) {
        keyfunc func = (kb_keyfunc(l, row, col));
        // FIXME don't re-send normal keys until we have key repeats
        if (is_layer_keyfunc(func)) {
          // FIXME this kinda shouldn't be here and it privileges layer 0 even more
          layers_pressed[row][col] = 0;
          exec_key(l, row, col, false);

          if (! layer_sticky[l]) { // don't resend for sticky keys
            layers_pressed[row][col] = layers_top;
            exec_key(layers_top, row, col, true);
          }
        }
      }
    }
  }
}

bool is_layer_keyfunc(keyfunc f) {
  for (int i=0; i<array_length(_kb_layer_funcs); i++) {
    if (f == _kb_layer_funcs[i]) {
      return true;
    }
  }
  return false;
}

// ----------------------------------------------------------------------------
// layout info
// ----------------------------------------------------------------------------

keycode kb_keycode	(layer l, u8 row, u8 col)	{ return (keycode) pgm_read_byte(&(_kb_layout_code[row][col][l])); }
keyfunc kb_keyfunc	(layer l, u8 row, u8 col)	{ return (keyfunc) pgm_read_word(&(_kb_layout_func[row][col][l])); }

// ----------------------------------------------------------------------------
// keyfunc primitives
// ----------------------------------------------------------------------------

// basic keypresses
void _kbfun_normal_press_release(keycode key, bool is_pressed) {
  if (key == 0) { return; } // noop

  if (is_pressed) {
    for (u8 i=0; i < sizeof(keyboard_keys); i++) {
      if (keyboard_keys[i] == 0) {
        keyboard_keys[i] = key;
        return;
      }
    }
  } else {
    for (u8 i=0; i < sizeof(keyboard_keys); i++) {
      if (keyboard_keys[i] == key) {
        keyboard_keys[i] = 0;
        return;
      }
    }
  }
}

void _kbfun_mediakey_press_release(keycode key, bool is_pressed) {
  media_keycode media_key = _media_code_lookup(key);
  if (is_pressed) {
    consumer_key = media_key;
  } else {
    // only one media key can be pressed at a time, so only clear most recent one
    if (media_key == consumer_key) {
      consumer_key = 0;
    }
  }
}

void _kbfun_modifier_press_release(keycode key, bool is_pressed) {
  if (is_pressed) {
    set_bit(keyboard_modifier_keys, key);
  } else {
    unset_bit(keyboard_modifier_keys, key);
  }
}

bool _kbfun_normal_is_pressed(keycode key) {
  for (u8 i=0; i < sizeof(keyboard_keys); i++) {
    if (keyboard_keys[i] == key) {
      return true;
    }
  }

  return false;
}

bool _kbfun_mediakey_is_pressed(keycode key) {
  return (consumer_key != 0);
}

bool _kbfun_modifier_is_pressed(keycode key) {
  return is_set(keyboard_modifier_keys, key);
}

void _kbfun_normal_sticky_done() {
  layer_sticky_done	= true;
  mod_sticky_done  	= true;
}

// ----------------------------------------------------------------------------
// basic keyfuncs
// ----------------------------------------------------------------------------

// execute the keypress or keyrelease function (if it exists) of the key at the current possition
void exec_key(layer layer, u8 row, u8 col, bool is_pressed) {
  keycode key                        	= kb_keycode(layer, row, col);
  void (*key_function)(keycode, bool)	= kb_keyfunc(layer, row, col);

  if (key_function) { (*key_function)(key, is_pressed); }
}

// normal key
void kbfun_normal_press_release(keycode key, bool is_pressed) {
  _kbfun_normal_sticky_done();
  _kbfun_normal_press_release(key, is_pressed);
}

// media key
void kbfun_mediakey_press_release(keycode key, bool is_pressed) {
  _kbfun_normal_sticky_done();
  _kbfun_mediakey_press_release(key, is_pressed);
}

// modifier
void kbfun_modifier_press_release(keycode key, bool is_pressed) {
  layer_sticky_done = true;
  _kbfun_modifier_press_release(key, is_pressed);
}

// layer key
void kbfun_layer_press_release(keycode key, bool is_pressed) {
  layer_sticky_done = true; // don't disable sticky mods!

  layer l = (layer) key;
  if (is_pressed) {
    layer_enable(l);
  } else {
    layer_disable(l);
  }
}

// sticky layer key
void kbfun_layer_sticky(keycode key, bool is_pressed) {
  layer l = (layer) key;

  if (is_pressed) {
    if (! layer_sticky[l]) {
      layer_enable(l);
      layer_sticky_done = false;
    }
  } else {
    if (layer_sticky_done) {
      layer_disable(l);
    } else {
      layer_sticky[l]  	= true;
      layer_sticky_on  	= true;
      layer_sticky_done	= false;
    }
  }
}

// sticky modifier key
void kbfun_modifier_sticky(keycode key, bool is_pressed) {
  // TODO handle: sticky, then same modifier
  keycode mod = key;

  if (is_pressed) {
    kbfun_modifier_press_release(key, true);
    mod_sticky_done = false;
  } else {
    if (mod_sticky_done) {
      kbfun_modifier_press_release(key, false);
    } else {
      set_bit(mod_sticky, mod);
      mod_sticky_done = false;
    }
  }
}

// ----------------------------------------------------------------------------
// combo keyfuncs
// ----------------------------------------------------------------------------

void _kbfun_combo_normal_press_release(keycode combo_key, keycode key, bool is_pressed) {
  _kbfun_modifier_press_release(combo_key, is_pressed);
  kbfun_normal_press_release(key, is_pressed);
}

void _kbfun_combo_normal_press_release_once(keycode combo_key, keycode key, bool is_pressed) {
  // FIXME this should be cleaner when we have actual key repeats

  if (is_pressed) {
    // avoid messing with independently pressed modifiers
    bool mod_already_pressed = _kbfun_modifier_is_pressed(combo_key);

    if (!mod_already_pressed) {
      _kbfun_modifier_press_release(combo_key, true);
    }

    kbfun_normal_press_release(key, true);

    if (!mod_already_pressed) {
      // we force a keyboard send to prevent the modifier from bleeding into the next key press
      usb_keyboard_send();
      _kbfun_modifier_press_release(combo_key, false);
    }
  } else {
    kbfun_normal_press_release(key, false);
  }
}

void _kbfun_combo_layer_press_release(keycode combo_key, keycode key, bool is_pressed) {
  kbfun_layer_press_release(key, is_pressed);
  _kbfun_modifier_press_release(combo_key, is_pressed);
}

void kbfun_shift_press_release(keycode key, bool is_pressed)  	{ _kbfun_combo_normal_press_release(MOD_KEY_LeftShift, key, is_pressed); }  	// +shift
void kbfun_control_press_release(keycode key, bool is_pressed)	{ _kbfun_combo_normal_press_release(MOD_KEY_LeftControl, key, is_pressed); }	// +control
void kbfun_alt_press_release(keycode key, bool is_pressed)    	{ _kbfun_combo_normal_press_release(MOD_KEY_LeftAlt, key, is_pressed); }    	// +alt
void kbfun_win_press_release(keycode key, bool is_pressed)    	{ _kbfun_combo_normal_press_release(MOD_KEY_LeftGUI, key, is_pressed); }    	// +win

void kbfun_shift_press_release_once(keycode key, bool is_pressed)  	{ _kbfun_combo_normal_press_release_once(MOD_KEY_LeftShift, key, is_pressed); }  	// +shift once
void kbfun_control_press_release_once(keycode key, bool is_pressed)	{ _kbfun_combo_normal_press_release_once(MOD_KEY_LeftControl, key, is_pressed); }	// +control once
void kbfun_alt_press_release_once(keycode key, bool is_pressed)    	{ _kbfun_combo_normal_press_release_once(MOD_KEY_LeftAlt, key, is_pressed); }    	// +alt once
void kbfun_win_press_release_once(keycode key, bool is_pressed)    	{ _kbfun_combo_normal_press_release_once(MOD_KEY_LeftGUI, key, is_pressed); }    	// +win once

void kbfun_shift_layer_press_release(keycode key, bool is_pressed)  	{ _kbfun_combo_layer_press_release(MOD_KEY_LeftShift, key, is_pressed); }  	// +shift + layer
void kbfun_control_layer_press_release(keycode key, bool is_pressed)	{ _kbfun_combo_layer_press_release(MOD_KEY_LeftControl, key, is_pressed); }	// +control + layer
void kbfun_alt_layer_press_release(keycode key, bool is_pressed)    	{ _kbfun_combo_layer_press_release(MOD_KEY_LeftAlt, key, is_pressed); }    	// +alt + layer
void kbfun_win_layer_press_release(keycode key, bool is_pressed)    	{ _kbfun_combo_layer_press_release(MOD_KEY_LeftGUI, key, is_pressed); }    	// +win + layer

// capslock
void kbfun_capslock_press_release(keycode key, bool is_pressed) {
  static u8  	keys_pressed;
  static bool	lshift_pressed;
  static bool	rshift_pressed;

  if (!is_pressed) { keys_pressed--; }

  // take care of the key that was actually pressed
  _kbfun_modifier_press_release(key, is_pressed);

  // take care of capslock (only on the press of the 2nd key)
  if (keys_pressed == 1 && is_pressed) {
    // save the state of left and right shift
    lshift_pressed = _kbfun_modifier_is_pressed(MOD_KEY_LeftShift);
    rshift_pressed = _kbfun_modifier_is_pressed(MOD_KEY_RightShift);
    // disable both
    _kbfun_modifier_press_release(MOD_KEY_LeftShift, false);
    _kbfun_modifier_press_release(MOD_KEY_RightShift, false);

    // press capslock, then release it
    _kbfun_normal_press_release(KEY_CapsLock, true); 	usb_keyboard_send();
    _kbfun_normal_press_release(KEY_CapsLock, false);	usb_keyboard_send();

    // restore the state of left and right shift
    if (lshift_pressed)	{ _kbfun_modifier_press_release(MOD_KEY_LeftShift, 	true);	}
    if (rshift_pressed)	{ _kbfun_modifier_press_release(MOD_KEY_RightShift,	true);	}
  }

  if (is_pressed) { keys_pressed++; }
}