#include "raylib.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include "../util.h"

typedef char cell;
#define MINE        0b10000000
#define MARKED      0b01000000
#define EXPOSED     0b00100000
#define NUMBERED    0b00010000
#define CELL_NUMBER 0b00000111

/*
  cell is a char (8 bits)
  0000 0000
  ^^^^  ^^^
  ||||  number of mine neigbours
  ||||> 1 if is a number
  |||> 1 if exposed (revealed)
  ||> 1 if marked
  |> 1 if mine
*/

typedef struct minefield_t {
    int row;
    int col;
    cell* cells;
    int mine_count;
} Minefield;

static inline cell get_cell(Minefield* mf, int r, int c){
    return mf->cells[r * mf->col + c];
}

static inline cell set_cell(Minefield* mf, int r, int c, cell cell){
    return mf->cells[r * mf->col + c] = cell;
}

Minefield make_minefield(int row, int col, int mine_count);
void free_minefield(Minefield* mf);
char cell_char(cell c);
void print_minefield(Minefield *mf, FILE *stream);
void draw_minefield(Minefield* mf);
cell* clicked_cell(Minefield* mf, int x, int y);
void expose_cell(Minefield* mf, int r, int c);
void handle_click(Minefield* mf);

typedef enum screens {
    GAME_LOOP,
    GAME_OVER,
    HELP,
} Screen;

Screen game_loop(Minefield* mf);
/* Screen game_over(Minefield* mf); */
Screen help_screen(Minefield* mf);

Screen (*screen_fn(Screen scr))(Minefield *);
Screen last_screen;

const int screenWidth = 800;
const int screenHeight = 450;
float cell_size;
int mark_count;
bool dead;

int main(){
    srand(time(NULL));
    Minefield mf = make_minefield(10, 20, 30);
    /* print_minefield(&mf, stdout); */
    dead = false;
    mark_count = 0;
    {
        float width = (float) screenWidth / mf.col;
        float height = (float) screenHeight / mf.row;
        cell_size = width > height ? height : width;
    }

    InitWindow(screenWidth, screenHeight, "Minesweeper");
    SetTargetFPS(60);

    Screen screen = GAME_LOOP;
    Screen (*loop)(Minefield*);
    while(!WindowShouldClose()){
        loop = screen_fn(screen);
        screen = (*loop)(&mf);
    }

    free_minefield(&mf);

    return 0;
}

Screen game_loop(Minefield* mf){
    while(!WindowShouldClose()){

        if (IsKeyPressed(KEY_H)){
            break;
        }

        if (!dead){
            handle_click(mf);
        }

        BeginDrawing();
        ClearBackground(RAYWHITE);
        draw_minefield(mf);
        EndDrawing();
    }
    last_screen = GAME_LOOP;
    return HELP;
}

Screen help_screen(Minefield* mf){
    while(!WindowShouldClose() && IsKeyDown(KEY_H)){

        BeginDrawing();
        ClearBackground(RAYWHITE);
        DrawText("Left Mouse Click - Open tile.", 100, 100, 30, BLACK);
        DrawText("Right Mouse Click - Mark tile.", 100, 150, 30, BLACK);
        EndDrawing();
    }
    return last_screen;
}

Screen (*screen_fn(Screen scr))(Minefield *) {
  switch (scr) {
  case GAME_LOOP:
    return game_loop;
  /* case GAME_OVER: */
  /*     return game_loop; */
  case HELP:
    return help_screen;
  default:
    return game_loop;
  }
}

Minefield make_minefield(int row, int col, int mine_count){
    Minefield mf = {.row = row, .col = col};
    int size = mf.row * mf.col;
    mf.cells = (cell *)calloc(size, sizeof(cell));
    mf.mine_count = mine_count;
    // 0 initialization
    for (int i = 0; i < size; i++) {
        mf.cells[i] = 0;
    }

    // Place mines
    /* float prob = (float) mine_count / f.row * f.col; */
    for (int m = mine_count; m > 0;){
        for (int i = 0; i < size; i++){
            if (!(mf.cells[i] & MINE) && (rand() % size) < mine_count) {
                mf.cells[i] = MINE;
                if (--m <= 0) {
                    break;
                }
            }
        }
    }

    // Place numbers
    for (int i = 0; i < mf.row; i++){
        for (int j = 0; j < mf.col; j++){
            if (!(get_cell(&mf, i, j) & MINE)){
                cell c = 0;
                for (int ii = imax(i - 1, 0); ii < imin(i + 2, mf.row); ii++){
                    for (int jj = imax(j - 1, 0); jj < imin(j + 2, mf.col); jj++){
                        if (get_cell(&mf, ii, jj) & MINE){
                            c++;
                        }
                    }
                }
                set_cell(&mf, i, j, c | NUMBERED);
            }
        }
    }
    return mf;
}

void free_minefield(Minefield* mf){
    if (mf){
        free(mf->cells);
        mf->cells = NULL;
    }
}

char cell_char(cell c){
    if (c & MARKED) {
        return 'X';
    } else if (c & MINE) {
        return '*';
    } else {
        c &= CELL_NUMBER;
        return c > 0 ? c + '0' : ' ';
    }
}
void print_minefield(Minefield *mf, FILE *stream){
    for (int i = 0; i < mf->row; i++) {
        for (int j = 0; j < mf->col; j++) {
            fputc('|', stream);
            cell c = mf->cells[i * mf->col + j];
            fputc(cell_char(c), stream);
        }
        fputs("|\n", stream);
    }
}

void draw_minefield(Minefield* mf){
    char str[2] = "0";
    for (int i = 0; i < mf->row; i++){
        for (int j = 0; j < mf->col; j++){
            int x = cell_size * j;
            int y = cell_size * i;
            DrawRectangleLines(x, y, cell_size, cell_size, BLACK);
            cell c = get_cell(mf, i, j);
            if (c & EXPOSED){
                str[0] = cell_char(c);
                DrawText(str, x + cell_size / 3, y + cell_size / 3, 20, BLACK);
            } else {
                DrawRectangle(x + 2, y + 2 , cell_size - 4, cell_size - 4,
                              c & MARKED ? RED : GRAY);
            }
        }
    }
    char time_str[20];
    float time = GetTime();
    snprintf(time_str, 20, "%02d.%02d - %d/%d",
             (int) time / 60, (int) time % 60,
             mark_count, mf->mine_count);
    DrawText(time_str, screenWidth / 2 - 20, screenHeight - 30, 20, BLACK);
}

cell* clicked_cell(Minefield* mf, int x, int y){
    int r = y / cell_size;
    int c = x / cell_size;
    if (r >= 0 && r < mf->row && c >= 0 && c < mf->col) {
        return &mf->cells[r * mf->col + c];
    }
    return NULL;
}

void expose_cell(Minefield* mf, int r, int c){
    cell* cel = &mf->cells[r * mf->col + c];
    *cel |= EXPOSED;
    if (*cel & NUMBERED && (*cel & CELL_NUMBER) == 0) {
        for (int i = imax(r - 1, 0); i < imin(r + 2, mf->row); i++){
            for (int j = imax(c - 1, 0); j < imin(c + 2, mf->col); j++){
                cell tcell = get_cell(mf, i, j);
                if (tcell & EXPOSED ||
                    !(tcell & NUMBERED)){
                    continue;
                }
                expose_cell(mf, i, j);
            }
        }
    }
}

void handle_click(Minefield* mf){
    if (IsMouseButtonPressed(MOUSE_BUTTON_LEFT)){
        int r = GetMouseY() / cell_size;
        int c = GetMouseX() / cell_size;

        if (!(r >= 0 && r < mf->row && c >= 0 && c < mf->col)) {
            printf("Click outside range, (%d, %d)\n", r, c);
            return;
        }
        cell cell = get_cell(mf, r, c);

        if (cell & MARKED){
            return;
        }  else if (cell & MINE){
            printf("DIED\n");
            expose_cell(mf, r, c);
            dead = true;
        } else {
            expose_cell(mf, r, c);
        }
    } else if (IsMouseButtonPressed(MOUSE_BUTTON_RIGHT)){
        int r = GetMouseY() / cell_size;
        int c = GetMouseX() / cell_size;

        if (!(r >= 0 && r < mf->row && c >= 0 && c < mf->col)) {
            printf("Click outside range, (%d, %d)\n", r, c);
            return;
        }
        mark_count += mf->cells[r * mf->col + c] & MARKED ? -1 : 1;
        mf->cells[r * mf->col + c] ^= MARKED;
    }
}