#include <stdio.h>
#include <limits.h>
#include "calc.h"

/** Text Editing **/

// Get the number of tokens in the current list
static inline int8_t tokenCount()
{
    return using_func_tokens?
            sizeof(func_tokens) / sizeof(func_tokens[0]) :
            sizeof(tokens) / sizeof(tokens[0]);
}

// Get current token from tokens[] or func_tokens[], as appropriate
static inline const char* getToken(int8_t n)
{
    int8_t t = n % tokenCount();
    return using_func_tokens? func_tokens[t] : tokens[t];
}

// Update the current code text with the contents of `mytext`,
// and add the current selected_token to the end
static void updateText()
{
    const char *token = getToken(selected_token);

    strcpy(temptext, mytext);

    strcat(temptext, token[0] == ' ' ? "_":     // Display space as underscore
                     token[0] == '\n'? "\\n":   // Display newline as \n
                     token);                    // Display others literally

    text_layer_set_text(s_input_text_layer, temptext);
}

// Cycle through the current list of tokens
static void cycle_tokens(ClickRecognizerRef recognizer, void *context)
{
    // Change current token
    if(click_recognizer_get_button_id(recognizer) == BUTTON_ID_DOWN)
        selected_token++;
    else
        selected_token--;

    // If selected token is outside of range, wrap around
    if(selected_token < 0)
        selected_token = tokenCount() - 1;
    else if(selected_token >= tokenCount())
        selected_token = 0;

    updateText();
}

static const char *fonts[] = {
    FONT_KEY_GOTHIC_28_BOLD,
    FONT_KEY_GOTHIC_24_BOLD,
    FONT_KEY_GOTHIC_18_BOLD,
    FONT_KEY_GOTHIC_14_BOLD
};

static const int smallestFont = 3;

static void adjustFont()
{
    int i = 0;
    int size = 0;
    while(temptext[i++]) {
        if(temptext[i] == '\n')
            size += 10;
        size++;
    }
    int f = size < 50 ? smallestFont - 3 :
            size < 100 ? smallestFont - 2 :
            size < 130 ? smallestFont - 1 :
            smallestFont;
    text_layer_set_font(s_input_text_layer,
            fonts_get_system_font(fonts[f]));
}

static void custom_unload(Window *window)
{
    text_layer_destroy(s_heading_text_layer);

    window_destroy(window);
    s_custom_window = NULL;
}

/**
 * In normal token list, backspace if possible, otherwise return to script list
 * In function token list, return to normal token list
 */
static void click_backspace(ClickRecognizerRef recognizer, void *context)
{
    if(s_custom_window) {
        window_stack_remove(s_custom_window, true);
        return;
    }

    if(!using_func_tokens) {
        if(mytext[0] == '\0') {
            window_stack_remove(window_stack_get_top_window(), true);
        } else {
            mytext[strlen(mytext) - 1] = '\0';
            updateText();
        }
    } else {
        using_func_tokens = false;
        updateText();
    }
    adjustFont();
}

// Adds the current string to the main string
static void add_token()
{
    strcat(mytext, getToken(selected_token));
    selected_token = 0;
    if(using_func_tokens) {
        using_func_tokens = false;
    }

    updateText();
    adjustFont();
}

/** Code running and saving **/

// Calculate result, display it and reset
static void calculate()
{
    Object obj = parseEval(mytext, &env);
    char temp[RESULT_LENGTH-2] = "";

    stringObj(temp, &obj);
    snprintf(resulttext, RESULT_LENGTH, "R:%s", temp);
    text_layer_set_text(s_result_text_layer, resulttext);
}

// Button press handler
static void click_select(ClickRecognizerRef recognizer, void *context)
{
    if(!using_func_tokens && selected_token == tokenCount() - 1) {
        calculate();
    } else if(!using_func_tokens && selected_token == tokenCount() - 2) {
        using_func_tokens = true;
        selected_token = 0;
        updateText();
    } else {
        add_token();
    }
}

// Saves text in editor to persistent storage
static void click_save(ClickRecognizerRef recognizer, void *context)
{
    int8_t i = strlen(temptext);
    for(unsigned j = 0; j < strlen(getToken(selected_token)); j++) {
        temptext[i-(1 + j)] = '\0';
    }

    persist_write_string(current_code, temptext);
    window_stack_pop(true);
}

// Sets the code_window click functions
static void code_click_subscribe(void *context)
{
    window_single_repeating_click_subscribe(BUTTON_ID_UP, 100, cycle_tokens);
    window_single_repeating_click_subscribe(BUTTON_ID_DOWN, 100, cycle_tokens);
    window_single_click_subscribe(BUTTON_ID_SELECT, click_select);
    window_long_click_subscribe(BUTTON_ID_SELECT, 500, click_save, NULL);
    window_single_click_subscribe(BUTTON_ID_BACK, click_backspace);
}

static void code_window_load(Window *window)
{
    Layer *window_layer = window_get_root_layer(window);
    GRect bounds = layer_get_bounds(window_layer);

    // Register click config provider
    window_set_click_config_provider(s_code_window, code_click_subscribe);

    // Input text layer setup
    s_input_text_layer = text_layer_create(bounds);
    text_layer_set_text(s_input_text_layer, getToken(1));
    text_layer_set_font(s_input_text_layer, fonts_get_system_font(FONT_KEY_GOTHIC_28_BOLD));
    layer_add_child(window_get_root_layer(s_code_window), text_layer_get_layer(s_input_text_layer));

    // Result text layer setup
    GRect result_bounds = GRect(6, 128, 132, 132);
    s_result_text_layer = text_layer_create(result_bounds);
    text_layer_set_text(s_result_text_layer, "R: ");
    text_layer_set_font(s_result_text_layer, fonts_get_system_font(FONT_KEY_GOTHIC_18_BOLD));
    text_layer_set_text_alignment(s_result_text_layer, GTextAlignmentRight);
    layer_add_child(window_get_root_layer(s_code_window), text_layer_get_layer(s_result_text_layer));

    // Push the window, setting the window animation to 'true'
    window_stack_push(s_code_window, true);

    // If possible, load the previous code text
    if(persist_exists(current_code)) {
        persist_read_string(current_code, mytext, SMAX_LENGTH);
        updateText();
        adjustFont();
    }
}

static void code_window_unload(Window *window)
{
    // Save the current code text
    persist_write_string(current_code, temptext);

    text_layer_destroy(s_result_text_layer);
    text_layer_destroy(s_input_text_layer);

    window_destroy(window);
    s_code_window = NULL;
}

void code_window_push()
{
    if(!s_code_window) {
        s_code_window = window_create();
        WindowHandlers wh = {
            .load = code_window_load,
            .unload = code_window_unload };
        window_set_window_handlers(s_code_window, wh);
    }

    window_stack_push(s_code_window, true);
}

/** Menu Window **/

static void select_callback(struct MenuLayer *menu_layer,
                            MenuIndex *cell_index, void *context) 
{
    current_code = cell_index->row;
    code_window_push();
}

static uint16_t get_num_rows_callback(MenuLayer *menu_layer,
                                      uint16_t section_index, void *context)
{
    return SCRIPT_COUNT;
}

static void draw_row_callback(GContext *ctx, const Layer *cell_layer,
                                        MenuIndex *cell_index, void *context)
{
    static char s_buff[16];
    snprintf(s_buff, sizeof(s_buff), "Script %d", 1 + (int)cell_index->row);

    // Draw this row's index
    menu_cell_basic_draw(ctx, cell_layer, s_buff, NULL, NULL);
}

static int16_t get_cell_height_callback(struct MenuLayer *menu_layer,
                                        MenuIndex *cell_index, void *context)
{
    return CELL_HEIGHT;
}

static void menu_load(Window *window)
{
    Layer *window_layer = window_get_root_layer(window);
    GRect bounds = layer_get_bounds(window_layer);

    s_menu_layer = menu_layer_create(bounds);
    menu_layer_set_click_config_onto_window(s_menu_layer, window);

    #if defined(PBL_COLOR)
    menu_layer_set_normal_colors(s_menu_layer, GColorBlack, GColorWhite);
    menu_layer_set_highlight_colors(s_menu_layer, GColorDukeBlue, GColorWhite);
    #endif

    menu_layer_set_callbacks(s_menu_layer, NULL, (MenuLayerCallbacks) {
        .get_num_rows = get_num_rows_callback,
        .draw_row = draw_row_callback,
        .get_cell_height = get_cell_height_callback,
        .select_click = select_callback,
    });
    layer_add_child(window_layer, menu_layer_get_layer(s_menu_layer));
}

static void menu_unload(Window *window)
{
    menu_layer_destroy(s_menu_layer);
}

/** Custom Window **/

static void custom_load(Window *window)
{
    Layer *window_layer = window_get_root_layer(window);
    GRect bounds = layer_get_bounds(window_layer);

    // Register click config provider
    window_set_click_config_provider(s_custom_window, code_click_subscribe);

    // Header text layer setup
    s_heading_text_layer = text_layer_create(bounds);
    text_layer_set_text(s_heading_text_layer, header);
    text_layer_set_font(s_heading_text_layer, 
                        fonts_get_system_font(FONT_KEY_BITHAM_30_BLACK));
    layer_add_child(window_get_root_layer(s_custom_window),
                    text_layer_get_layer(s_heading_text_layer));

    // Push the window, setting the window animation to 'true'
    window_stack_push(s_custom_window, true);
}

Object add_window(Object obj1, Object obj2, struct Environment *env)
{
    printf("ADD_WINDOW\n");
    if(obj1.type == TYPE_STRING) {
        strcpy(header, obj1.string);
    }

    if(!s_custom_window) {
        s_custom_window = window_create();
        WindowHandlers wh = {
            .load = custom_load,
            .unload = custom_unload };
        window_set_window_handlers(s_custom_window, wh);
    }

    window_stack_push(s_custom_window, true);

    return numberObject(1);
}

static void inbox_received_callback(DictionaryIterator *iter, void *context) {
    Tuple *script_tuple = dict_find(iter, MESSAGE_KEY_ScriptText);
    if(script_tuple) {
        if(!s_code_window) {
            current_code = 0;
            code_window_push();
        }
        char *script_text = script_tuple->value->cstring;
        snprintf(temptext, sizeof(temptext), "%s", script_text);
        snprintf(mytext, sizeof(mytext), "%s", script_text);
        updateText();
    }
}

/** General **/

static struct Environment pebbleEnv()
{
    struct Environment e = defaultEnv();
    // Needs two args
    addFunc("window", &add_window, &e);
    parseEval("(def win (fn (a) (window a 1)))", &e);
    return e;
}

static void init(void)
{
    env = pebbleEnv();
    s_menu_window = window_create();
    window_set_window_handlers(s_menu_window, (WindowHandlers) {
        .load = menu_load,
        .unload = menu_unload
    });
    window_stack_push(s_menu_window, true);
    app_message_open(inbox_size, outbox_size);
    app_message_register_inbox_received(inbox_received_callback);
}

static void deinit(void)
{
    deleteEnv(&env);
    text_layer_destroy(s_input_text_layer);
    window_destroy(s_menu_window);
}

int main(void)
{
    init();
    app_event_loop();
    deinit();
}