/**
 * Foundry-facing scene assembly (generic across all generators).
 *
 * Takes a uniform MapResult (svg + wall segments + notes + lights) and produces
 * a real Foundry scene with a raster background. Everything is flagged for
 * later cleanup. Uses Foundry globals — browser only.
 *
 * MapResult shape:
 *   { width, height, gridSize, backgroundColor, segments, svg, notes, lights }
 */

import { PIECES, pieceSpriteSVG } from "./furniture.mjs";

const MODULE_ID = "mapwright";
const SPRITE_PPC = 128;              // sprite resolution per grid cell
const _spriteCache = new Set();      // paths known to exist this session

const C = () => ({
  MOVE_NORMAL: CONST.WALL_MOVEMENT_TYPES?.NORMAL ?? 20,
  SENSE_NONE: CONST.WALL_SENSE_TYPES?.NONE ?? 0,
  SENSE_NORMAL: CONST.WALL_SENSE_TYPES?.NORMAL ?? 20,
  DOOR_NONE: CONST.WALL_DOOR_TYPES?.NONE ?? 0,
  DOOR_BASIC: CONST.WALL_DOOR_TYPES?.DOOR ?? 1,
  DS_CLOSED: CONST.WALL_DOOR_STATES?.CLOSED ?? 0,
  DS_LOCKED: CONST.WALL_DOOR_STATES?.LOCKED ?? 2,
  GRID_SQUARE: CONST.GRID_TYPES?.SQUARE ?? 1
});

/**
 * @param {object} result MapResult
 * @param {object} meta   { name, gridSize, seed, subtype, tokenVision }
 * @returns {Promise<Scene>}
 */
export async function createScene(result, meta) {
  const k = C();
  const gs = result.gridSize ?? meta.gridSize ?? 70;
  const W = result.width;
  const H = result.height;

  const filename = `${slug(meta.name)}-${Date.now()}.png`;
  const bgPath = await rasterAndUpload(result.svg, W, H, filename);

  const bgColor = result.backgroundColor ?? "#000000";
  const sceneData = {
    name: meta.name,
    width: W,
    height: H,
    padding: 0.0,
    grid: { type: k.GRID_SQUARE, size: gs },
    // Default: a flat, fully-visible battlemap that matches the preview.
    // Dynamic lighting (token vision + ambient lights) is opt-in.
    tokenVision: meta.tokenVision ?? false,
    flags: { [MODULE_ID]: { generated: true, seed: meta.seed, subtype: meta.subtype } }
  };
  if (meta.folderId) sceneData.folder = meta.folderId;
  const scene = await Scene.create(sceneData);

  await applyBackground(scene, bgPath, bgColor);

  const wallDocs = (result.segments ?? []).map((s) => segmentToWall(s, gs, k));
  if (wallDocs.length) await scene.createEmbeddedDocuments("Wall", wallDocs);

  if (result.lights?.length) await scene.createEmbeddedDocuments("AmbientLight", result.lights);
  if (result.notes?.length) await scene.createEmbeddedDocuments("Note", result.notes);
  if (result.placements?.length) await createFurnitureTiles(scene, result.placements, meta.subtype);

  return scene;
}

/**
 * Create a multi-floor building as a folder of linked scenes.
 * @param {object[]} results  one MapResult per floor (each may carry floorName)
 * @param {object} meta       { name, gridSize, seed, subtype }
 * @returns {Promise<Scene[]>}
 */
export async function createSceneSet(results, meta) {
  const folder = await Folder.create({ name: meta.name, type: "Scene" });
  const scenes = [];
  for (let i = 0; i < results.length; i += 1) {
    const r = results[i];
    const scene = await createScene(r, {
      ...meta,
      name: `${meta.name} — ${r.floorName ?? `Floor ${i + 1}`}`,
      folderId: folder.id
    });
    scenes.push(scene);
  }
  if (scenes[0]) await scenes[0].view?.();
  return scenes;
}

/**
 * Apply the background image to a scene, handling the v14 Levels architecture.
 *
 * In Foundry v14 `Scene#background` is deprecated — the image lives on the
 * scene's default Level (`scene.levels` → `level.background.src`). On v12/v13
 * the image is the scene's own `background.src`. This sets whichever applies.
 */
async function applyBackground(scene, src, color) {
  if (!scene) return false;

  // v14+: background lives on the scene's (auto-created) default Level.
  const levels = scene.levels;
  if (levels && (levels.size ?? levels.length)) {
    const first = levels.get?.(scene.initialLevel?._id ?? scene.initialLevel) ?? [...levels][0];
    if (first) {
      await scene.updateEmbeddedDocuments("Level", [{ _id: first.id, background: { src, color } }]);
      const ok = scene.levels.get(first.id)?.background?.src === src;
      if (ok) console.log(`Mapwright: scene "${scene.name}" background set on level → ${src}`);
      else console.warn(`Mapwright: level background did not apply (wanted "${src}").`);
      return ok;
    }
  }

  // v12/v13 fallback: background on the scene document itself.
  await scene.update({ background: { src, color } });
  const ok = scene.background?.src === src;
  if (!ok) {
    console.warn(`Mapwright: scene background did not apply (got "${scene.background?.src}", wanted "${src}").`);
    ui.notifications?.warn?.("Mapwright: map image uploaded but the scene background didn't apply — see console (F12).");
  }
  return ok;
}

function segmentToWall(s, gs, k) {
  const c = [
    Math.round(s.x1 * gs), Math.round(s.y1 * gs),
    Math.round(s.x2 * gs), Math.round(s.y2 * gs)
  ];
  const base = {
    c,
    move: k.MOVE_NORMAL,
    sight: k.SENSE_NORMAL,
    sound: k.SENSE_NORMAL,
    light: k.SENSE_NORMAL,
    flags: { [MODULE_ID]: { generated: true, kind: s.kind } }
  };
  if (s.kind === "door") {
    base.door = k.DOOR_BASIC;
    base.ds = s.locked ? k.DS_LOCKED : k.DS_CLOSED;
  } else if (s.kind === "window") {
    base.sight = k.SENSE_NONE;
    base.light = k.SENSE_NONE;
  } else if (s.kind === "water") {
    // Deep water: blocks movement only; sight/sound/light pass freely.
    base.sight = k.SENSE_NONE;
    base.sound = k.SENSE_NONE;
    base.light = k.SENSE_NONE;
  }
  return base;
}

function filePicker() {
  return foundry.applications?.apps?.FilePicker?.implementation
    ?? foundry.applications?.apps?.FilePicker
    ?? FilePicker;
}

/** Normalise an upload path to a clean relative form Foundry will accept. */
function cleanPath(p) {
  return String(p ?? "")
    .replace(/^https?:\/\/[^/]+/i, "")
    .replace(/^\/+/, "")
    .replace(/^\.\//, "");
}

/** Rasterise an SVG string to a PNG Blob (transparent where the SVG is). */
async function svgToPngBlob(svg, w, h) {
  const blob = new Blob([svg], { type: "image/svg+xml;charset=utf-8" });
  const url = URL.createObjectURL(blob);
  try {
    const img = new Image();
    img.width = w; img.height = h;
    await new Promise((resolve, reject) => {
      img.onload = resolve;
      img.onerror = () => reject(new Error("SVG rasterisation failed"));
      img.src = url;
    });
    try { if (img.decode) await img.decode(); } catch (e) { /* best-effort */ }
    const canvas = document.createElement("canvas");
    canvas.width = w; canvas.height = h;
    canvas.getContext("2d").drawImage(img, 0, 0, w, h);
    const png = await new Promise((resolve) => canvas.toBlob(resolve, "image/png"));
    if (!png) throw new Error("Mapwright: canvas.toBlob returned null.");
    return png;
  } finally {
    URL.revokeObjectURL(url);
  }
}

async function uploadBlob(blob, dir, filename) {
  const FP = filePicker();
  try { await FP.createDirectory("data", dir); } catch (e) { /* exists */ }
  const file = new File([blob], filename, { type: "image/png" });
  const upload = await FP.upload("data", dir, file, {}, { notify: false });
  if (!upload?.path) throw new Error("Mapwright: upload failed (no path). Check file-upload permission.");
  return cleanPath(upload.path);
}

async function rasterAndUpload(svg, w, h, filename) {
  const png = await svgToPngBlob(svg, w, h);
  const path = await uploadBlob(png, MODULE_ID, filename);
  console.log(`Mapwright: background uploaded → "${path}" (${Math.round(png.size / 1024)} KB)`);
  return path;
}

/** Ensure a furniture sprite PNG exists; returns its served path. Cached. */
async function ensureSprite(kind, subtype) {
  const filename = `${subtype}-${kind}.png`;
  const path = `${MODULE_ID}/furniture/${filename}`;
  if (_spriteCache.has(path)) return path;
  // Check if already uploaded (persists across sessions).
  try {
    const listing = await filePicker().browse("data", `${MODULE_ID}/furniture`);
    if (listing?.files?.some((f) => cleanPath(f).endsWith(filename))) { _spriteCache.add(path); return path; }
  } catch (e) { /* dir may not exist yet */ }
  const def = PIECES[kind];
  if (!def) return null;
  const [pw, ph] = def.footprint;
  const w = pw * SPRITE_PPC, h = ph * SPRITE_PPC;
  const png = await svgToPngBlob(pieceSpriteSVG(kind, subtype, w, h), w, h);
  const uploaded = await uploadBlob(png, `${MODULE_ID}/furniture`, filename);
  _spriteCache.add(uploaded);
  return uploaded;
}

/** Create locked furniture Tiles from placements. */
async function createFurnitureTiles(scene, placements, subtype) {
  if (!placements?.length) return;
  // Resolve sprite paths (unique per kind).
  const paths = {};
  for (const kind of new Set(placements.map((p) => p.kind))) {
    try { paths[kind] = await ensureSprite(kind, subtype); } catch (e) { console.warn(`Mapwright: sprite for "${kind}" failed`, e); }
  }
  const tiles = [];
  for (const p of placements) {
    const src = paths[p.kind];
    if (!src) continue;
    tiles.push({
      texture: { src },
      x: Math.round(p.cx - p.wpx / 2),
      y: Math.round(p.cy - p.hpx / 2),
      width: Math.round(p.wpx),
      height: Math.round(p.hpx),
      rotation: p.rotation ?? 0,
      locked: true,
      sort: 0,
      flags: { [MODULE_ID]: { generated: true, kind: p.kind } }
    });
  }
  if (tiles.length) await scene.createEmbeddedDocuments("Tile", tiles);
}

function slug(str) {
  return String(str || "map").toLowerCase().replace(/[^a-z0-9]+/g, "-").replace(/^-+|-+$/g, "") || "map";
}