import { getWall, isSolid, getOverlayDef, getItemDef } from './registry.js';
import { DOOR_SLIDE_MS, DOOR_OPEN_MS } from './constants.js';

/** Runtime wrapper around a LevelData grid. Shared by the game (collision +
 *  raycasting) and the editor (paint/erase). Keeps all grid-index math in one
 *  place so the two never disagree about what is solid or in-bounds. */
export class GameMap {
  constructor(level) {
    this.width = level.width;
    this.height = level.height;
    // Defensive copy so mutations (editor painting) don't alias the source.
    this.tiles = level.tiles.slice();

    // Sparse per-cell wall overlays (paintings etc.), keyed y*width+x.
    this.overlays = new Map();
    for (const o of level.overlays ?? []) {
      if (this.inBounds(o.x, o.y) && typeof o.id === 'string') {
        this.overlays.set(o.y * this.width + o.x, o.id);
      }
    }

    // Cells made impassable by blocking items (plants, lamps, …). Items are
    // not walls: rays, shots, and sight pass over them; only movement stops.
    this.blocked = new Set();
    for (const it of level.items ?? []) {
      if (getItemDef(it.id)?.blocking && this.inBounds(it.x, it.y)) {
        this.blocked.add(Math.floor(it.y) * this.width + Math.floor(it.x));
      }
    }

    // Sliding doors: one state record per door tile, keyed y*width+x.
    // state: 'closed' | 'opening' | 'open' | 'closing'
    // openness: 0 (fully closed) → 1 (fully open); the raycaster reads this to
    // draw the door partially slid aside, and isWall() treats only fully-open
    // doors as passable.
    this.doors = new Map();
    for (let i = 0; i < this.tiles.length; i++) {
      const def = getWall(this.tiles[i]);
      if (def.isDoor) {
        this.doors.set(i, {
          cx: i % this.width,
          cy: Math.floor(i / this.width),
          def,
          state: 'closed',
          openness: 0,
          timer: 0,
        });
      }
    }
  }

  inBounds(x, y) {
    return x >= 0 && y >= 0 && x < this.width && y < this.height;
  }

  /** Tile id at integer cell (x, y). Out-of-bounds reads as solid wall id 1 so
   *  rays and movement treat the world edge as a wall. */
  tileAt(x, y) {
    const cx = Math.floor(x);
    const cy = Math.floor(y);
    if (!this.inBounds(cx, cy)) return 1;
    return this.tiles[cy * this.width + cx];
  }

  setTile(x, y, id) {
    const cx = Math.floor(x);
    const cy = Math.floor(y);
    if (!this.inBounds(cx, cy)) return;
    this.tiles[cy * this.width + cx] = id;
  }

  /** Whether a wall blocks sight/shots/rays at this cell. A door counts as a
   *  wall until it has slid fully open. */
  isWall(x, y) {
    if (!isSolid(this.tileAt(x, y))) return false;
    const door = this.doorAt(x, y);
    return door ? door.state !== 'open' : true;
  }

  /** Whether movement is blocked here — by a wall or by a blocking item. */
  isBlocked(x, y) {
    if (this.isWall(x, y)) return true;
    const cx = Math.floor(x);
    const cy = Math.floor(y);
    return this.inBounds(cx, cy) && this.blocked.has(cy * this.width + cx);
  }

  isDoor(x, y) {
    return getWall(this.tileAt(x, y)).isDoor;
  }

  /** The door state record at (x, y), or null. */
  doorAt(x, y) {
    return this.doors.get(Math.floor(y) * this.width + Math.floor(x)) ?? null;
  }

  /** How far open the door at (x, y) is (0 closed … 1 open); 0 if no door. */
  doorOpenness(x, y) {
    return this.doorAt(x, y)?.openness ?? 0;
  }

  /** Player pressed "use" on this cell. Toggles the door if there is one and
   *  it isn't locked. Returns:
   *    { used: false }                 — no door here
   *    { used: false, locked: keyId }  — locked; the player lacks the key
   *    { used: true }                  — door is now opening/closing */
  useDoor(x, y, keys = new Set()) {
    const door = this.doorAt(x, y);
    if (!door) return { used: false };
    if (door.state === 'closed' || door.state === 'closing') {
      const needed = door.def.key;
      if (needed && !keys.has(needed)) return { used: false, locked: needed };
      door.state = 'opening';
    } else if (door.state === 'open') {
      door.state = 'closing';
    }
    return { used: true }; // an already-opening door swallows the press
  }

  /** Advance door animations. `occupied` is the player's cell — a door won't
   *  auto-close on top of them. */
  updateDoors(deltaMs, occupied) {
    for (const door of this.doors.values()) {
      switch (door.state) {
        case 'opening':
          door.openness += deltaMs / DOOR_SLIDE_MS;
          if (door.openness >= 1) {
            door.openness = 1;
            door.state = 'open';
            door.timer = DOOR_OPEN_MS;
          }
          break;
        case 'open':
          door.timer -= deltaMs;
          if (door.timer <= 0) {
            if (occupied && occupied.x === door.cx && occupied.y === door.cy) {
              door.timer = DOOR_SLIDE_MS; // stand in the doorway → stay open
            } else {
              door.state = 'closing';
            }
          }
          break;
        case 'closing':
          door.openness -= deltaMs / DOOR_SLIDE_MS;
          if (door.openness <= 0) {
            door.openness = 0;
            door.state = 'closed';
          }
          break;
      }
    }
  }

  /** Overlay def on the wall cell at (x, y), or null. */
  overlayAt(x, y) {
    const id = this.overlays.get(Math.floor(y) * this.width + Math.floor(x));
    return id ? getOverlayDef(id) : null;
  }

  /** Set (id string) or clear (null) the overlay on a cell — editor brush. */
  setOverlay(x, y, id) {
    const cx = Math.floor(x);
    const cy = Math.floor(y);
    if (!this.inBounds(cx, cy)) return;
    const key = cy * this.width + cx;
    if (id) this.overlays.set(key, id);
    else this.overlays.delete(key);
  }

  /** Snapshot the grid back into a plain array (for serialization). */
  getTiles() {
    return this.tiles.slice();
  }

  /** Snapshot overlays as the level file's [{x, y, id}] array. */
  getOverlays() {
    return [...this.overlays.entries()].map(([key, id]) => ({
      x: key % this.width,
      y: Math.floor(key / this.width),
      id,
    }));
  }
}