#include "map.h"
#include "rng.h"
#include "utils.h"
#include <string.h>

void map_init(Map *map) {
  // Fill entire map with walls
  for (int y = 0; y < MAP_HEIGHT; y++) {
    for (int x = 0; x < MAP_WIDTH; x++) {
      map->tiles[y][x] = TILE_WALL;
    }
  }
  map->room_count = 0;
}

int is_floor(Map *map, int x, int y) {
  if (!in_bounds(x, y, MAP_WIDTH, MAP_HEIGHT))
    return 0;
  return map->tiles[y][x] == TILE_FLOOR || map->tiles[y][x] == TILE_STAIRS;
}

void get_room_center(Room *room, int *cx, int *cy) {
  *cx = room->x + room->w / 2;
  *cy = room->y + room->h / 2;
}

// Carve a room into the map
static void carve_room(Map *map, Room *room) {
  for (int y = room->y; y < room->y + room->h; y++) {
    for (int x = room->x; x < room->x + room->w; x++) {
      if (in_bounds(x, y, MAP_WIDTH, MAP_HEIGHT)) {
        map->tiles[y][x] = TILE_FLOOR;
      }
    }
  }
}

// Carve a horizontal corridor
static void carve_h_corridor(Map *map, int x1, int x2, int y) {
  int start = (x1 < x2) ? x1 : x2;
  int end = (x1 < x2) ? x2 : x1;
  for (int x = start; x <= end; x++) {
    if (in_bounds(x, y, MAP_WIDTH, MAP_HEIGHT)) {
      map->tiles[y][x] = TILE_FLOOR;
    }
  }
}

// Carve a vertical corridor
static void carve_v_corridor(Map *map, int x, int y1, int y2) {
  int start = (y1 < y2) ? y1 : y2;
  int end = (y1 < y2) ? y2 : y1;
  for (int y = start; y <= end; y++) {
    if (in_bounds(x, y, MAP_WIDTH, MAP_HEIGHT)) {
      map->tiles[y][x] = TILE_FLOOR;
    }
  }
}

// Check if a room overlaps with existing rooms
static int room_overlaps(Room *rooms, int count, Room *new_room) {
  // Add padding to prevent rooms from touching
  for (int i = 0; i < count; i++) {
    Room *r = &rooms[i];
    if (!(new_room->x > r->x + r->w || new_room->x + new_room->w < r->x ||
          new_room->y > r->y + r->h || new_room->y + new_room->h < r->y)) {
      return 1;
    }
  }
  return 0;
}

// Generate rooms for this floor
static int generate_rooms(Map *map, Room *rooms, int floor) {
  int room_count = 0;
  int attempts = 0;
  int max_attempts = 100;

  // Room count varies by floor, but capped at max_rooms
  int target_rooms = 5 + (floor % 3) + rng_int(0, 3);
  if (target_rooms > MAX_ROOMS)
    target_rooms = MAX_ROOMS;

  while (room_count < target_rooms && attempts < max_attempts) {
    attempts++;

    // Random room dimensions
    int w = rng_int(5, 12);
    int h = rng_int(5, 10);

    // Random position (within map bounds with 1-tile border)
    int x = rng_int(2, MAP_WIDTH - w - 2);
    int y = rng_int(2, MAP_HEIGHT - h - 2);

    Room new_room = {x, y, w, h};

    // Check for overlap
    if (!room_overlaps(rooms, room_count, &new_room)) {
      rooms[room_count] = new_room;
      carve_room(map, &new_room);
      room_count++;
    }
  }

  return room_count;
}

// Connect all rooms with corridors
static void connect_rooms(Map *map, Room *rooms, int room_count) {
  for (int i = 0; i < room_count - 1; i++) {
    int cx1, cy1, cx2, cy2;
    get_room_center(&rooms[i], &cx1, &cy1);
    get_room_center(&rooms[i + 1], &cx2, &cy2);

    // Carve L-shaped corridor between rooms
    if (rng_int(0, 1) == 0) {
      carve_h_corridor(map, cx1, cx2, cy1);
      carve_v_corridor(map, cx2, cy1, cy2);
    } else {
      carve_v_corridor(map, cx1, cy1, cy2);
      carve_h_corridor(map, cx1, cx2, cy2);
    }
  }
}

// Place stairs in the last room (furthest from start)
static void place_stairs(Map *map, Room *rooms, int room_count) {
  if (room_count > 0) {
    Room *last_room = &rooms[room_count - 1];
    int cx, cy;
    get_room_center(last_room, &cx, &cy);

    // Place stairs at center of last room
    if (in_bounds(cx, cy, MAP_WIDTH, MAP_HEIGHT)) {
      map->tiles[cy][cx] = TILE_STAIRS;
    }
  }
}

// Get a random floor tile (for player/enemy spawn)
void get_random_floor_tile(Map *map, int *x, int *y, int attempts) {
  *x = -1;
  *y = -1;

  for (int i = 0; i < attempts; i++) {
    int tx = rng_int(1, MAP_WIDTH - 2);
    int ty = rng_int(1, MAP_HEIGHT - 2);

    if (map->tiles[ty][tx] == TILE_FLOOR) {
      *x = tx;
      *y = ty;
      return;
    }
  }

  // Fallback: search from top-left
  for (int ty = 1; ty < MAP_HEIGHT - 1; ty++) {
    for (int tx = 1; tx < MAP_WIDTH - 1; tx++) {
      if (map->tiles[ty][tx] == TILE_FLOOR) {
        *x = tx;
        *y = ty;
        return;
      }
    }
  }
}

void dungeon_generate(Dungeon *d, Map *map, int floor_num) {
  // Seed RNG with floor number for deterministic generation
  rng_seed(floor_num * 12345);

  // Initialize map to all walls
  map_init(map);

  // Generate rooms
  map->room_count = generate_rooms(map, map->rooms, floor_num);

  // Connect rooms with corridors
  connect_rooms(map, map->rooms, map->room_count);

  // Place stairs in last room
  place_stairs(map, map->rooms, map->room_count);

  // Store dungeon state
  d->current_floor = floor_num;
  d->room_count = map->room_count;
  memcpy(d->rooms, map->rooms, sizeof(Room) * map->room_count);
}