#include <stdlib.h>
#include <string.h>

#include <dirent.h>

#include "menu.h"
#include "file.h"
#include "timer.h"


static int get_input(nese_Components* comp, int *last) {
    int status = nes_input_update(comp->reader, comp);
    int new_buttons = comp->sys->input.controllers[0].buttons;
    if (0 == status) {
        status = (~*last & new_buttons);
    } else {
        status = (status << 8);
    }
    *last = new_buttons;
    return status;
}

static int wait_for_input(nese_Components* comp) {
    int buttons = comp->sys->input.controllers[0].buttons;
    int status = 0;
    for (   ;
            0 == status;
            status = get_input(comp, &buttons) ) {
        time_sleep(US_PER_S / 60);
    }
    return status;
}

static int wait_for_input_quiet(nese_Components* comp) {
    int status = 0;
    while ( input_Result_Quit != status &&
            comp->sys->input.controllers[0].buttons) {
        time_sleep(US_PER_S / 60);
        status = nes_input_update(comp->reader, comp);
    }
    return (    input_Result_Quit == status ?
                input_Result_Quit : 0);
}

static int count_files(DIR* dir) {
    int count = 0;
    struct dirent* de = NULL;
    while (NULL != (de = readdir(dir))) {
        if ('.' != de->d_name[0]) ++count;
    }
    rewinddir(dir);
    return count;
}

typedef struct {
    int count;
    char** files;
} file_list;

int cmp_files(const void* _a, const void* _b) {
    const char* a = *(const char**)_a;
    const char* b = *(const char**)_b;

    int diff = 0;
    for (char ca = 1, cb = 1; ca && cb && 0 == diff; ++a, ++b) {
        // Cut extensions; replace underscore with space
        ca = (*a == '_' ? ' ' : (*a == '.' ? '\0' : *a));
        cb = (*b == '_' ? ' ' : (*b == '.' ? '\0' : *b));
        diff = (ca - cb);
    }

    return diff;
}

static void make_file_list(DIR* dir, file_list* files) {
    files->count = count_files(dir);
    files->files = calloc(files->count, sizeof(char*));
    struct dirent* de = NULL;
    int i_file = 0;
    while (NULL != (de = readdir(dir))) {
        if ('.' != de->d_name[0]) {
            files->files[i_file] = strdup(de->d_name);
            ++i_file;
        }
    }
    qsort(files->files, files->count, sizeof(char*), cmp_files);
}

static void free_file_list(file_list* files) {
    for (int i = 0; i < files->count; ++i) {
        free(files->files[i]);
    }
    free(files->files);
}

static int find_file(file_list* files, const char* filename) {
    int i = (files->count - 1);
    for ( ; i >= 0 &&
            (0 != strcmp(files->files[i], filename)); --i);
    return i;
}

static void fix_filename(char* dst, int n, const char* src) {
    for (   int i = 0;
            i < n && *src && '.' != *src;
            ++i, ++dst, ++src) {
        *dst = ('_' == *src ? ' ' : *src);
    }
    *dst = '\0';
}

static inline int n_visible(void) {
    return ((nes_ppu_render_h - 20) / 11);
}

static const uint32_t menu_colors[6] = {
    color_red, color_orange, color_yellow,
    color_green, color_blue, color_purple,
};

static void show_menu(const menu_state* menu, int dim, int x,
                      nes_Renderer* rend,
                      const file_list* files) {
    nes_draw_last_frame(rend, dim);

    int bottom = menu->top + n_visible() - 1;

    int max = n_visible();
    if (max > files->count) max = files->count;
    int y = (nes_ppu_render_h - (max * 11)) / 2;

    for (   int n = menu->top;
            n < files->count && n <= bottom;
            ++n, y += 11 ) {
        char filename[100];
        fix_filename(filename, sizeof(filename) - 1,
                     files->files[n]);
        nes_draw_text(
                rend,
                ( (menu->top == n && 0 != menu->top) ||
                  (bottom == n && files->count - 1 > bottom) ) ?
                  "..." : filename,
                x, y,
                (menu->cursor == n) ?
                    color_white : menu_colors[n % 6]
            );
        if (menu->cursor == n) {
            nes_draw_text(rend, ">", x - 10, y,
                          color_white);
        }
    }

    nes_draw_done(rend);
}

static int run_menu(menu_state* state, const file_list* files,
                    int x, nese_Components* comp,
                    const cart_info* cart) {
    menu_state menu = {0};
    if (NULL != state) {
        menu = *state;
        if (menu.cursor < 0) {
            menu.cursor = 0;
        } else if (menu.cursor >= files->count) {
            menu.cursor = files->count - 1;
        }
    }

    int status = 0;
    while (0 == status) {
        // Scrolling (do this first to ensure menu is valid)
        const int visible = n_visible() - 1;
        menu.top = menu.cursor - (visible / 2);
        if (menu.top <= 0) {
            // We use <= so we don't readjust the top from 0
            menu.top = 0;
        } else if (menu.top + visible >= files->count) {
            menu.top = (files->count - 1) - visible;
        }

        show_menu(&menu, NULL != cart->file, x,
                  comp->rend, files);

        int buttons = wait_for_input(comp);
        int special = (buttons >> 8);

        if (input_Result_Quit == special) {
            status = special;

        } else if ( input_Result_Menu == special ||
                    (buttons & (1 << Button_B))) {
            status = input_Result_Cancel;

        } else if (buttons & (  (1 << Button_A) |
                                (1 << Button_Start) )) {
            // Select
            break;

        } else if (buttons & (1 << Button_Up)) {
            if (menu.cursor > 0) --menu.cursor;

        } else if (buttons & (  (1 << Button_Down) |
                                (1 << Button_Select) )) {
            if (menu.cursor < (files->count - 1)) {
                ++menu.cursor;
            } else if (buttons & (1 << Button_Select)) {
                // Wrap around on Select
                menu.cursor = 0;
            }
        }
    }

    if (NULL != state) *state = menu;

    return status;
}


char* run_main_menu(menu_state* state, nese_Components* comp,
                    const cart_info* cart) {
    char* cart_filename = NULL;

    DIR* dir = opendir("rom");

    if (NULL == dir) {
        modal_popup(
                "No ROMS found!\nPress any key to exit",
                comp, cart
            );

    } else {
        file_list files = {0};
        make_file_list(dir, &files);
        closedir(dir);

        menu_state menu = {0};
        if (NULL != state) menu = *state;

        if (NULL != cart->filename) {
            // Add 4 to skip past "rom/"
            int current = find_file(&files, cart->filename + 4);
            if (current >= 0) menu.cursor = current;
        }

        // Don't let window refreshes interrupt us.
        int status = run_menu(&menu, &files, 20, comp, cart);

        if (input_Result_Quit == status) {
            cart_filename = (char*)-1;

        } else if (input_Result_Cancel == status) {
            cart_filename = NULL;

        } else if ( menu.cursor >= 0 &&
                    menu.cursor < files.count) {
            char filename[1024];
            snprintf(filename, sizeof(filename) - 1,
                     "%s/%s", "rom", files.files[menu.cursor]);
            cart_filename = strdup(filename);
        }

        free_file_list(&files);

        if (NULL != state) *state = menu;
    }

    return cart_filename;
}

int run_game_menu(menu_state* state, nese_Components* comp,
                  const nese_State* nese) {
    char* items[] = {
        "Resume",
        "Save",
        "Restore",
        "Reset",
        "Select ROM",
#ifndef STANDALONE
        (nese->flags & (1 << State_Bit_Fullscreen)) ?
            "Windowed" : "Fullscreen",
#endif
        (nese->flags & (1 << State_Bit_Integer_Scale)) ?
            "Force Aspect" : "Integer Scaling",
        "Exit",
    };
    static const int choices[] = {
        input_Result_OK,
        input_Result_Save,
        input_Result_Load,
        input_Result_Reset,
        input_Result_Menu,
#ifndef STANDALONE
        input_Result_View,
#endif
        input_Result_Scale,
        input_Result_Quit,
    };
    const file_list options = {
        .files = items,
        .count = (sizeof(items) / sizeof(*items)),
    };

    menu_state menu = {0};
    if (NULL != state) menu = *state;

    int status = run_menu(&menu, &options, 100,
                          comp, &nese->cart);

    if (input_Result_Menu == status) {
        status = input_Result_Cancel;
    }

    if (0 == status) status = choices[menu.cursor];

    wait_for_input_quiet(comp);

    if (NULL != state) *state = menu;

    return status;
}

int modal_popup(const char* message, nese_Components* comp,
                const cart_info* cart) {
    int w = 0;
    int h = 0;

    nes_text_size(comp->rend, message, &w, &h);

    int x = ((int)nes_ppu_render_w - w) / 2;
    int y = ((int)nes_ppu_render_h - h) / 2;

    if (x < 5) x = 5;
    if (y < 5) y = 5;

    nes_draw_last_frame(comp->rend, NULL != cart->file);
    nes_draw_text(comp->rend, message, x, y, color_error);
    nes_draw_done(comp->rend);

    return wait_for_input(comp);
}