/* ============================================================
 * Diablo2D — world.js : procedural dungeon & town generation
 * ============================================================ */
'use strict';
window.D2 = window.D2 || {};
(function (D2) {

  const T = { VOID: 0, FLOOR: 1, WALL: 2 };

  const THEMES = {
    cathedral: {
      gen: 'rooms', floorsPerRoom: 0.9,
      floorCols: ['#4a3f38', '#52453c', '#453b34', '#57493e'],
      wallTop: '#2c2622', wallFace: '#3a322c',
      accent: '#7a5a3a', torch: '#ff9a4a', fog: '#0a0806', ambient: 0.16,
      music: 'crypt',
    },
    catacombs: {
      gen: 'rooms',
      floorCols: ['#3a4048', '#414750', '#363c44', '#464c55'],
      wallTop: '#23282e', wallFace: '#30363d',
      accent: '#4a6a8a', torch: '#7ab8ff', fog: '#07090c', ambient: 0.12,
      music: 'crypt',
    },
    caves: {
      gen: 'caves',
      floorCols: ['#3e4a34', '#46523a', '#38442e', '#4d5940'],
      wallTop: '#242c20', wallFace: '#323e2a',
      accent: '#5a8a3a', torch: '#b8e86a', fog: '#080a06', ambient: 0.14,
      music: 'cave',
    },
    hell: {
      gen: 'caves',
      floorCols: ['#48302a', '#50362e', '#422a24', '#583a30'],
      wallTop: '#281512', wallFace: '#38201a',
      accent: '#c83a1a', torch: '#ff5a2a', fog: '#100604', ambient: 0.18,
      music: 'hell',
    },
    town: {
      gen: 'town',
      floorCols: ['#55503e', '#5c5644', '#4e4938', '#635d49'],
      wallTop: '#33291e', wallFace: '#453829',
      accent: '#8a7a4a', torch: '#ffb84a', fog: '#0c0a08', ambient: 0.32,
      music: 'town',
    },
  };

  /* ---------------- helpers ---------------- */

  function idx(w, x, y) { return y * w + x; }

  function inBounds(w, h, x, y) { return x >= 0 && y >= 0 && x < w && y < h; }

  /* ---------------- rooms & corridors generator ---------------- */

  function genRooms(rng, w, h, roomAttempts) {
    const tiles = new Uint8Array(w * h);
    const rooms = [];
    for (let i = 0; i < roomAttempts && rooms.length < 14; i++) {
      const rw = rng.int(6, 13), rh = rng.int(5, 10);
      const rx = rng.int(2, w - rw - 3), ry = rng.int(2, h - rh - 3);
      const room = { x: rx, y: ry, w: rw, h: rh, cx: (rx + rw / 2) | 0, cy: (ry + rh / 2) | 0 };
      if (rooms.some(r => overlap(room, r, 2))) continue;
      rooms.push(room);
      carveRect(tiles, w, room);
    }
    /* L corridors between consecutive rooms */
    for (let i = 1; i < rooms.length; i++) {
      const a = rooms[i - 1], b = rooms[i];
      carveL(tiles, w, a.cx, a.cy, b.cx, b.cy);
    }
    /* a couple of loops */
    for (let k = 0; k < 3 && rooms.length > 4; k++) {
      const a = rng.pick(rooms), b = rng.pick(rooms);
      if (a !== b) carveL(tiles, w, a.cx, a.cy, b.cx, b.cy);
    }
    return { tiles, rooms };
  }

  function overlap(a, b, pad) {
    return a.x - pad < b.x + b.w && a.x + a.w + pad > b.x &&
           a.y - pad < b.y + b.h && a.y + a.h + pad > b.y;
  }

  function carveRect(tiles, w, r) {
    for (let y = r.y; y < r.y + r.h; y++)
      for (let x = r.x; x < r.x + r.w; x++)
        tiles[idx(w, x, y)] = T.FLOOR;
  }

  function carveL(tiles, w, x0, y0, x1, y1) {
    let x = x0, y = y0;
    const horizFirst = Math.random() < 0.5;
    const step = () => { tiles[idx(w, x, y)] = T.FLOOR; };
    step();
    if (horizFirst) {
      while (x !== x1) { x += Math.sign(x1 - x); step(); }
      while (y !== y1) { y += Math.sign(y1 - y); step(); }
    } else {
      while (y !== y1) { y += Math.sign(y1 - y); step(); }
      while (x !== x1) { x += Math.sign(x1 - x); step(); }
    }
  }

  /* ---------------- cellular cave generator ---------------- */

  function genCaves(rng, w, h) {
    const tiles = new Uint8Array(w * h);
    const wallP = 0.44;
    for (let y = 0; y < h; y++)
      for (let x = 0; x < w; x++)
        tiles[idx(w, x, y)] = (x === 0 || y === 0 || x === w - 1 || y === h - 1 || rng.next() < wallP) ? T.WALL : T.FLOOR;

    for (let pass = 0; pass < 4; pass++) {
      const next = Uint8Array.from(tiles);
      for (let y = 1; y < h - 1; y++) {
        for (let x = 1; x < w - 1; x++) {
          let walls = 0;
          for (let dy = -1; dy <= 1; dy++)
            for (let dx = -1; dx <= 1; dx++) {
              if (!dx && !dy) continue;
              if (tiles[idx(w, x + dx, y + dy)] !== T.FLOOR) walls++;
            }
          next[idx(w, x, y)] = walls >= 5 ? T.WALL : T.FLOOR;
        }
      }
      tiles.set(next);
    }

    /* keep only the largest connected region */
    const seen = new Uint8Array(w * h);
    let best = null;
    for (let y = 0; y < h; y++) {
      for (let x = 0; x < w; x++) {
        const i0 = idx(w, x, y);
        if (tiles[i0] !== T.FLOOR || seen[i0]) continue;
        const region = [];
        const stack = [[x, y]];
        seen[i0] = 1;
        while (stack.length) {
          const [cx, cy] = stack.pop();
          region.push([cx, cy]);
          for (const [dx, dy] of [[1,0],[-1,0],[0,1],[0,-1]]) {
            const nx = cx + dx, ny = cy + dy;
            if (!inBounds(w, h, nx, ny)) continue;
            const ni = idx(w, nx, ny);
            if (!seen[ni] && tiles[ni] === T.FLOOR) { seen[ni] = 1; stack.push([nx, ny]); }
          }
        }
        if (!best || region.length > best.length) best = region;
      }
    }
    const keep = new Set(best.map(([x, y]) => idx(w, x, y)));
    for (let i = 0; i < tiles.length; i++)
      if (tiles[i] === T.FLOOR && !keep.has(i)) tiles[i] = T.VOID;

    /* pseudo-rooms = flood-fill pockets for prop/spawn logic */
    const rooms = [];
    const grid = {};
    for (const [x, y] of best) grid[x + ',' + y] = true;
    // sample room anchors on a coarse grid where floor exists
    for (let gy = 6; gy < h - 6; gy += 9) {
      for (let gx = 6; gx < w - 6; gx += 9) {
        if (grid[gx + ',' + gy]) rooms.push({ x: gx - 3, y: gy - 3, w: 7, h: 7, cx: gx, cy: gy });
      }
    }
    return { tiles, rooms };
  }

  /* ---------------- walls around floors ---------------- */

  function buildWalls(tiles, w, h) {
    const out = Uint8Array.from(tiles);
    for (let y = 0; y < h; y++) {
      for (let x = 0; x < w; x++) {
        if (tiles[idx(w, x, y)] !== T.VOID) continue;
        let touchesFloor = false;
        for (let dy = -1; dy <= 1 && !touchesFloor; dy++)
          for (let dx = -1; dx <= 1; dx++) {
            const nx = x + dx, ny = y + dy;
            if (inBounds(w, h, nx, ny) && tiles[idx(w, nx, ny)] === T.FLOOR) { touchesFloor = true; break; }
          }
        if (touchesFloor) out[idx(w, x, y)] = T.WALL;
      }
    }
    return out;
  }

  /* ---------------- floor assembly ---------------- */

  /**
   * opts: { act, floorIdx, seed, bossLair, torment }
   * Returns the World object used by simulation & rendering.
   */
  function generateFloor(opts) {
    const act = opts.act | 0;
    const floorIdx = opts.floorIdx | 0;
    const themeId = D2.BAL.acts[act].theme;
    const theme = THEMES[themeId];
    const rng = new D2.util.RNG(opts.seed >>> 0);
    const isBoss = !!opts.bossLair;

    const w = isBoss ? 52 : 62, h = isBoss ? 38 : 62;
    let tiles, rooms;

    if (isBoss) {
      tiles = new Uint8Array(w * h);
      const m = 4;
      const room = { x: m, y: m, w: w - m * 2, h: h - m * 2 };
      carveRect(tiles, w, room);
      rooms = [room];
      /* pillars for cover */
      for (let py = room.y + 4; py < room.y + room.h - 3; py += 6) {
        for (let px = room.x + 5; px < room.x + room.w - 4; px += 8) {
          tiles[idx(w, px, py)] = T.WALL;
          tiles[idx(w, px + 1, py)] = T.WALL;
        }
      }
    } else if (theme.gen === 'rooms') {
      ({ tiles, rooms } = genRooms(rng, w, h, 90));
    } else {
      ({ tiles, rooms } = genCaves(rng, w, h));
    }

    const finalTiles = buildWalls(tiles, w, h);

    /* variants for art */
    const variant = new Uint8Array(w * h);
    for (let i = 0; i < variant.length; i++) variant[i] = (rng.next() * 4) | 0;

    const world = {
      w, h,
      tiles: finalTiles,
      variant,
      theme, themeId, act, floorIdx,
      isBossLair: isBoss,
      seed: opts.seed >>> 0,
      torment: opts.torment | 0,
      rooms,
      props: [],
      propMap: new Map(),          // "x,y" -> blocking prop
      spawns: [],
      visible: new Uint8Array(w * h),
      explored: new Uint8Array(w * h),
      torches: [],                 // light sources {x,y,color,r,flicker}
      spawnX: 0, spawnY: 0,
      stairsDown: null, stairsUp: null,
      mlvl: D2.BAL.monsterLevel(act, floorIdx, opts.torment | 0),

      tileAt(x, y) { return inBounds(w, h, x, y) ? finalTiles[idx(w, x, y)] : T.VOID; },
      isWalkable(x, y) {
        if (this.tileAt(Math.floor(x), Math.floor(y)) !== T.FLOOR) return false;
        return !this.propMap.has(Math.floor(x) + ',' + Math.floor(y));
      },
      transparent(x, y) { return this.tileAt(x, y) === T.FLOOR; },
      randomFloorIn(room) {
        for (let tries = 0; tries < 30; tries++) {
          const x = rng.int(room.x, room.x + room.w - 1);
          const y = rng.int(room.y, room.y + room.h - 1);
          if (finalTiles[idx(w, x, y)] === T.FLOOR && !this.propMap.has(x + ',' + y)) return { x, y };
        }
        return null;
      },
      addProp(p) {
        p.uid = D2.util.uid();
        this.props.push(p);
        if (p.blocking) this.propMap.set(p.x + ',' + p.y, p);
        if (p.type === 'torch') this.torches.push({ x: p.x, y: p.y });
        return p;
      },
      removeProp(p) {
        const i = this.props.indexOf(p);
        if (i >= 0) this.props.splice(i, 1);
        this.propMap.delete(p.x + ',' + p.y);
      },
    };

    /* ---- spawn point = first room center ---- */
    const startRoom = rooms[0];
    world.spawnX = startRoom.cx; world.spawnY = startRoom.cy;

    /* ---- stairs ---- */
    if (!isBoss) {
      const lastRoom = farthestRoom(world, rooms, startRoom);
      const sp = world.randomFloorIn(lastRoom) || { x: lastRoom.cx, y: lastRoom.cy };
      world.stairsDown = { x: sp.x, y: sp.y };
      world.addProp({ type: 'stairs_down', x: sp.x, y: sp.y, blocking: false });
    } else {
      world.stairsUp = { x: startRoom.cx, y: startRoom.cy };
      world.addProp({ type: 'stairs_up', x: startRoom.cx, y: startRoom.cy, blocking: false });
    }

    populateProps(world, rng, theme);
    populateMonsters(world, rng, act, isBoss);
    ensureRouteToStairs(world);

    return world;
  }

  /* Remove blocking props along one spawn→stairs route so caves
     with 1-wide tunnels can never be sealed by barrels. */
  function ensureRouteToStairs(world) {
    if (!world.stairsDown || world.isTown) return;
    const tilesPath = D2.path.find(
      (x, y) => world.transparent(x, y),
      world.w, world.h,
      world.spawnX, world.spawnY,
      world.stairsDown.x, world.stairsDown.y, 30000);
    if (!tilesPath) return;
    for (const n of tilesPath) {
      const pr = world.propMap.get(n.x + ',' + n.y);
      if (pr && pr.blocking) world.removeProp(pr);
    }
  }

  function farthestRoom(world, rooms, from) {
    let best = rooms[rooms.length - 1], bestD = -1;
    for (const r of rooms) {
      const d = (r.cx - from.cx) ** 2 + (r.cy - from.cy) ** 2;
      if (d > bestD) { bestD = d; best = r; }
    }
    return best;
  }

  /* ---------------- props ---------------- */

  function populateProps(world, rng, theme) {
    const { w, h } = world;
    const at = (x, y) => world.tileAt(x, y) === T.FLOOR && !world.propMap.has(x + ',' + y);

    /* torches along walls */
    const torchSpots = [];
    for (let y = 1; y < h - 1; y++)
      for (let x = 1; x < w - 1; x++)
        if (world.tiles[idx(w, x, y)] === T.WALL &&
            world.tileAt(x, y + 1) === T.FLOOR)
          torchSpots.push([x, y]);
    rng.shuffle(torchSpots);
    const torchCount = Math.min(18, torchSpots.length);
    for (let i = 0; i < torchCount; i++) {
      const [x, y] = torchSpots[i];
      world.addProp({ type: 'torch', x, y: y, blocking: false, light: true });
    }

    if (world.isBossLair) {
      /* a chest behind the boss area */
      return;
    }

    for (const room of world.rooms.slice(1)) {
      /* barrels & urns */
      const clusterN = rng.int(0, 3);
      for (let c = 0; c < clusterN; c++) {
        const bx = rng.int(room.x + 1, room.x + room.w - 2);
        const by = rng.int(room.y + 1, room.y + room.h - 2);
        const n = rng.int(1, 3);
        for (let i = 0; i < n; i++) {
          const x = Math.min(room.x + room.w - 1, bx + i % 2), y = by;
          if (at(x, y)) world.addProp({
            type: rng.chance(0.5) ? 'barrel' : 'urn',
            x, y, blocking: true, hp: 1,
          });
        }
      }
      /* chest */
      if (rng.chance(0.3)) {
        const spot = world.randomFloorIn(room);
        if (spot) world.addProp({ type: 'chest', x: spot.x, y: spot.y, blocking: true, opened: false });
      }
      /* shrine (rare) */
      if (rng.chance(0.05)) {
        const spot = world.randomFloorIn(room);
        if (spot) world.addProp({
          type: 'shrine', x: spot.x, y: spot.y, blocking: false, used: false,
          buff: rng.pick(['dmg', 'speed', 'armor', 'xp', 'regen']),
        });
      }
    }
  }

  /* ---------------- monsters ---------------- */

  function populateMonsters(world, rng, act, isBoss) {
    if (isBoss) {
      const bd = D2.Monsters.BOSS_MAP[D2.BAL.acts[act].boss];
      world.spawns.push({ boss: bd.id, x: world.w / 2, y: world.h * 0.68 });
      /* honor guard */
      const guard = D2.Monsters.rollSpeciesForAct(act);
      for (let i = 0; i < 4; i++) {
        world.spawns.push({ speciesId: guard.id, x: world.w / 2 + (rng.range(-5, 5)), y: world.h * 0.55 + rng.range(-2, 2), elite: false });
      }
      return;
    }

    const density = 0.55 + world.act * 0.12 + world.floorIdx * 0.05;
    for (const room of world.rooms.slice(1)) {
      if (world.stairsDown && room === nearestRoomToStairs(world)) continue;
      const packs = Math.max(1, Math.round((room.w * room.h) / 55 * density));
      for (let p = 0; p < packs; p++) {
        const species = D2.Monsters.rollSpeciesForAct(act);
        const packSize = species.ai === 'swarm' ? rng.int(3, 5) : rng.int(2, 4);
        const packElite = rng.chance(0.13);
        const base = world.randomFloorIn(room);
        if (!base) continue;
        for (let i = 0; i < packSize; i++) {
          const sx = Math.max(1, Math.min(world.w - 2, base.x + ((rng.next() * 5) | 0) - 2));
          const sy = Math.max(1, Math.min(world.h - 2, base.y + ((rng.next() * 5) | 0) - 2));
          if (world.tileAt(sx, sy) === T.FLOOR)
            world.spawns.push({ speciesId: species.id, x: sx, y: sy, elite: packElite });
        }
      }
    }
  }

  function nearestRoomToStairs(world) {
    if (!world.rooms.length || !world.stairsDown) return null;
    let best = null, bd = Infinity;
    for (const r of world.rooms) {
      const d = (r.cx - world.stairsDown.x) ** 2 + (r.cy - world.stairsDown.y) ** 2;
      if (d < bd) { bd = d; best = r; }
    }
    return best;
  }

  /* ---------------- town ---------------- */

  function generateTown(seed) {
    const w = 56, h = 40;
    const rng = new D2.util.RNG((seed ^ 0x7A6E) >>> 0);
    const theme = THEMES.town;
    const tiles = new Uint8Array(w * h).fill(T.VOID);

    const border = 2;
    for (let y = border; y < h - border; y++)
      for (let x = border; x < w - border; x++)
        tiles[idx(w, x, y)] = T.FLOOR;

    const world = {
      w, h, tiles, variant: new Uint8Array(w * h),
      theme, themeId: 'town', act: -1, floorIdx: -1,
      isBossLair: false, isTown: true, seed: seed >>> 0, torment: 0,
      rooms: [], props: [], propMap: new Map(),
      spawns: [], visible: new Uint8Array(w * h), explored: new Uint8Array(w * h),
      torches: [], spawnX: (w / 2) | 0, spawnY: (h * 0.62) | 0,
      stairsDown: null, stairsUp: null, mlvl: 1,

      tileAt(x, y) { return inBounds(w, h, x, y) ? tiles[idx(w, x, y)] : T.VOID; },
      isWalkable(x, y) {
        if (this.tileAt(Math.floor(x), Math.floor(y)) !== T.FLOOR) return false;
        return !this.propMap.has(Math.floor(x) + ',' + Math.floor(y));
      },
      transparent(x, y) { return this.tileAt(x, y) === T.FLOOR; },
      randomFloorIn(room) { return null; },
      addProp(p) {
        p.uid = D2.util.uid();
        this.props.push(p);
        if (p.blocking) this.propMap.set(p.x + ',' + p.y, p);
        if (p.type === 'torch') this.torches.push({ x: p.x, y: p.y });
        return p;
      },
      removeProp(p) {
        const i = this.props.indexOf(p);
        if (i >= 0) this.props.splice(i, 1);
        this.propMap.delete(p.x + ',' + p.y);
      },
    };

    /* Rogue-camp buildings along the top (charsi/akara/stash/kashya/cain/gheed) */
    const bw = 7, bh = 6;
    const buildings = [
      { x: 3,  npc: 'charsi' },   // blacksmith
      { x: 11, npc: 'akara' },    // healer & magic
      { x: 19, npc: 'stash' },    // camp storage
      { x: 27, npc: 'kashya' },   // rogue captain — hunt quests
      { x: 35, npc: 'cain' },     // elder lore — main quests
      { x: 43, npc: 'gheed' },    // gambler
    ].map(b => ({ ...b, w: bw, h: bh, y: 4 }));
    for (const b of buildings) {
      for (let y = b.y; y < b.y + b.h; y++)
        for (let x = b.x; x < b.x + b.w; x++)
          tiles[idx(w, x, y)] = T.WALL;
      /* doorway at bottom center */
      const doorX = b.x + (b.w >> 1);
      tiles[idx(w, doorX, b.y + b.h - 1)] = T.FLOOR;
      tiles[idx(w, doorX, b.y + b.h - 2)] = T.FLOOR;
      world.addProp({ type: 'npc_' + b.npc, x: doorX, y: b.y + b.h - 4, blocking: true });
      world.addProp({ type: 'torch', x: b.x - 1, y: b.y + b.h, blocking: false, light: true });
      world.addProp({ type: 'torch', x: b.x + b.w, y: b.y + b.h, blocking: false, light: true });
    }

    /* waypoint stone center */
    world.addProp({ type: 'waypoint', x: (w / 2) | 0, y: (h * 0.38) | 0, blocking: true });

    /* decorative props */
    for (let i = 0; i < 10; i++) {
      const x = rng.int(border + 1, w - border - 2), y = rng.int(h * 0.55 | 0, h - border - 2);
      if (world.tileAt(x, y) === T.FLOOR && !world.propMap.has(x + ',' + y))
        world.addProp({ type: rng.chance(0.5) ? 'barrel' : 'bones', x, y, blocking: rng.chance(0.5), hp: 1 });
    }
    /* fence posts around perimeter */
    for (let x = border; x < w - border; x += 3) {
      world.addProp({ type: 'bones', x, y: h - border, blocking: false });
      world.addProp({ type: 'bones', x, y: border - 1 >= 0 ? border : border, blocking: false });
    }

    /* explored everywhere in town */
    world.explored.fill(1);

    return world;
  }

  D2.world = { T, THEMES, generateFloor, generateTown };
})(window.D2);