#include <furi.h>
#include <furi_hal.h>
#include <dialogs/dialogs.h>
#include <gui/gui.h>
#include <input/input.h>
#include <m-string.h>
#include <stdlib.h>

typedef enum {
    EventTypeTick,
    EventTypeKey,
} EventType;

typedef struct {
    EventType type;
    InputEvent input;
} PluginEvent;


//QUEUE

struct node {
    int interval;
    struct node *next;
};
typedef struct node node;

typedef struct {
    int size;
    int max_size;
    node *front;
    node *rear;
} queue;

static void init_queue(queue *q) {
  q->size = 0;
  q->max_size = 5;
  q->front = NULL;
  q->rear = NULL;
}

static void queue_remove(queue *q) {
    node *tmp;
    tmp = q->front;
    q->front = q->front->next;
    q->size--;
    free(tmp);
}

static void queue_add(queue *q, int value) {
    node *tmp = malloc(sizeof(node));
    tmp->interval = value;
    tmp->next = NULL;
    if (q->size == q->max_size) {
      queue_remove(q);
    } 
    // check if empty
    if (q->rear == NULL) {
      q->front = tmp;
      q->rear = tmp;
    } else {
      q->rear->next = tmp;
      q->rear = tmp;
    }
    q->size++;
}

static float queue_avg(queue *q) {
    float avg = 0.0;
    if (q->size == 0){
      return avg;
    } else {
      node *tmp;
      float sum = 0.0;

      tmp = q->front;
      while (tmp != NULL) {
          sum = sum + tmp->interval;
          tmp = tmp->next;
      } 
      avg = sum / q->size;
      return avg;
    }
}

// TOO SLOW!
//uint64_t dolphin_state_timestamp() {
//    FuriHalRtcDateTime datetime;
//    furi_hal_rtc_get_datetime(&datetime);
//    return furi_hal_rtc_datetime_to_timestamp(&datetime);
//}
//
typedef struct {
    int taps;
    double bpm;
    uint32_t last_stamp;
    uint32_t interval;
    queue *tap_queue;
} BPMTapper;

static void show_hello() {

  // BEGIN HELLO DIALOG
  DialogsApp* dialogs = furi_record_open(RECORD_DIALOGS);
  DialogMessage* message = dialog_message_alloc();

  const char* header_text = "BPM Tapper";
  const char* message_text = "Tap center to start";

  dialog_message_set_header(message, header_text, 63, 3, AlignCenter, AlignTop);
  dialog_message_set_text(message, message_text, 0, 17, AlignLeft, AlignTop);
  dialog_message_set_buttons(message, NULL, "Tap", NULL);

  dialog_message_set_icon(message, &I_DolphinCommon_56x48, 72, 17);

  dialog_message_show(dialogs, message);

  dialog_message_free(message);
  furi_record_close(RECORD_DIALOGS);
  // END HELLO DIALOG
}

static void input_callback(InputEvent* input_event, FuriMessageQueue* event_queue) {
    furi_assert(event_queue); 

    PluginEvent event = {.type = EventTypeKey, .input = *input_event};
    furi_message_queue_put(event_queue, &event, FuriWaitForever);
}

static void render_callback(Canvas* const canvas, void* ctx) {
    string_t tempStr;

    const BPMTapper* bpm_state = acquire_mutex((ValueMutex*)ctx, 25);
    if (bpm_state == NULL) {
      return;
    }
    // border
    //canvas_draw_frame(canvas, 0, 0, 128, 64);
    canvas_set_font(canvas, FontPrimary);

    string_init(tempStr);

    string_printf(tempStr, "Taps: %d", bpm_state->taps);
    canvas_draw_str_aligned(canvas, 5, 15, AlignLeft, AlignBottom, string_get_cstr(tempStr));
    string_reset(tempStr);

    string_printf(tempStr, "Queue: %d", bpm_state->tap_queue->size);
    canvas_draw_str_aligned(canvas, 50, 15, AlignLeft, AlignBottom, string_get_cstr(tempStr));
    string_reset(tempStr);

    string_printf(tempStr, "Interval: %dms", bpm_state->interval);
    canvas_draw_str_aligned(canvas, 5, 25, AlignLeft, AlignBottom, string_get_cstr(tempStr));
    string_reset(tempStr);

    string_printf(tempStr, "%.2f", bpm_state->bpm);
    canvas_set_font(canvas, FontBigNumbers);
    canvas_draw_str_aligned(canvas, 20, 50, AlignLeft, AlignBottom, string_get_cstr(tempStr));
    string_reset(tempStr);

    string_clear(tempStr);

    release_mutex((ValueMutex*)ctx, bpm_state);
}


static void bpm_state_init(BPMTapper* const plugin_state) {
  plugin_state->taps = 0; 
  plugin_state->bpm = 120.0;
  plugin_state->last_stamp = 0;
  plugin_state->interval = 500;
  queue *q;
  q = malloc(sizeof(queue));
  init_queue(q);
  plugin_state->tap_queue = q;
}

int32_t bpm_tapper_app(void* p) {
  UNUSED(p);

  FuriMessageQueue* event_queue = furi_message_queue_alloc(8, sizeof(PluginEvent));
  
  BPMTapper* bpm_state = malloc(sizeof(BPMTapper));
  // setup
  bpm_state_init(bpm_state);
  
  ValueMutex state_mutex;
  if (!init_mutex(&state_mutex, bpm_state, sizeof(bpm_state))) {
      FURI_LOG_E("BPM-Tapper", "cannot create mutex\r\n");
      free(bpm_state);
      return 255;
  }
  show_hello();

  // BEGIN IMPLEMENTATION

  // Set system callbacks
  ViewPort* view_port = view_port_alloc(); 
  view_port_draw_callback_set(view_port, render_callback, &state_mutex);
  view_port_input_callback_set(view_port, input_callback, event_queue);
  
  // Open GUI and register view_port
  Gui* gui = furi_record_open("gui"); 
  gui_add_view_port(gui, view_port, GuiLayerFullscreen);

  PluginEvent event;
  for (bool processing = true; processing;) {
    FuriStatus event_status = furi_message_queue_get(event_queue, &event, 100);
    BPMTapper* bpm_state = (BPMTapper*)acquire_mutex_block(&state_mutex);
    if(event_status == FuriStatusOk) {
      // press events
      if(event.type == EventTypeKey) {
        if(event.input.type == InputTypePress) {  
          switch(event.input.key) {
            case InputKeyUp:
            case InputKeyDown:
            case InputKeyRight:
            case InputKeyLeft:
            case InputKeyOk:
              bpm_state->taps++;
              uint32_t new_stamp = furi_get_tick();
              bpm_state->interval = new_stamp - bpm_state->last_stamp;
              bpm_state->last_stamp = new_stamp;
              queue_add(bpm_state->tap_queue, bpm_state->interval);
              float avg = queue_avg(bpm_state->tap_queue);
              float bps = 1.0 / (avg / 1000.0);
              bpm_state->bpm = bps * 60.0;
              break;
            case InputKeyBack:
                // Exit the plugin
                processing = false;
                break;
          }
        }
      } 
    } else {
      FURI_LOG_D("BPM-Tapper", "FuriMessageQueue: event timeout");
    // event timeout
    }
    view_port_update(view_port);
    release_mutex(&state_mutex, bpm_state);
  }
  view_port_enabled_set(view_port, false);
  gui_remove_view_port(gui, view_port);
  furi_record_close("gui");
  view_port_free(view_port);
  furi_message_queue_free(event_queue);
  delete_mutex(&state_mutex);
  queue *q = bpm_state->tap_queue;
  free(q);
  free(bpm_state);

  return 0;
}