import { stringify } from "yaml";
import type { SceneEntity } from "@nengine/core-schema";
import {
  TILE_SIZE,
  addTileId,
  erase,
  isWalkableTile,
  markSaved as markMapSaved,
  paint,
  pointToTile,
  serialize as serializeMap,
  setSpawn,
  tileColor,
  toggleWalkable,
} from "./map-model.js";
import type { MapModel } from "./map-model.js";
import {
  SELECT_COLOR,
  addAnimal,
  addBuilding,
  addNpc,
  describeEntity,
  entityColor,
  entityFootprint,
  entityIndexAt,
  markSaved as markSceneSaved,
  moveEntity,
  removeEntity,
  serialize as serializeScene,
} from "./scene-model.js";
import type { SceneOpResult, SceneFootprint, SceneModel } from "./scene-model.js";
import type { PlaytestFlush } from "./playtest-session.js";

export interface SceneBuildingPaletteEntry {
  id: string;
  name?: string;
  footprint: SceneFootprint;
}

export interface SceneEditorOptions {
  root: string;
  scenePath: string;
  mapPath: string;
  mapModel: MapModel;
  sceneModel: SceneModel;
  /** Building palette entries with footprint data from the project's defs. */
  buildings: SceneBuildingPaletteEntry[];
  /** Animal ids from the project's animal defs. */
  animals: string[];
  onStatus: (message: string, isError?: boolean) => void;
  onSaved?: () => void;
  onFlush?: (collect: () => PlaytestFlush[]) => void;
}

type SceneEditorMode = "scene" | "map";
type MapTool = "paint" | "erase" | "spawn" | "walkable";
type ActivePlacement = { type: "building"; id: string } | { type: "animal"; id: string } | { type: "npc"; id: string } | null;

const MAP_TOOLS: { id: MapTool; label: string; title: string }[] = [
  { id: "paint", label: "Paint", title: "Left-click / drag paints the selected tile" },
  { id: "erase", label: "Erase", title: "Left-drag erases; right-click erases anywhere" },
  { id: "spawn", label: "Spawn", title: "Click moves the spawn point" },
  { id: "walkable", label: "Walkable", title: "Shows blocked tiles and toggles a tile id's walkability on click" },
];

export function mountSceneEditor(container: HTMLElement, options: SceneEditorOptions): () => void {
  const root = document.createElement("div");
  root.className = "scene-editor";
  container.replaceChildren(root);

  let mode: SceneEditorMode = "scene";
  let activePlacement: ActivePlacement = null;
  let selectedIndex: number | null = null;
  let mapTool: MapTool = "paint";
  let mapSelectedId = options.mapModel.palette[0] ?? "";
  let painting = false;
  let disposed = false;

  const toolbar = document.createElement("div");
  toolbar.className = "scene-toolbar";
  const title = document.createElement("h3");
  title.textContent = `Scene: ${options.sceneModel.def.id}`;
  const path = document.createElement("span");
  path.className = "scene-path";
  path.textContent = options.scenePath;
  path.title = options.scenePath;
  const modeToggle = document.createElement("div");
  modeToggle.className = "scene-mode-toggle";
  const modeButtons = new Map<SceneEditorMode, HTMLButtonElement>();
  for (const [value, label] of [["scene", "Edit Scene"], ["map", "Edit Map"]] as const) {
    const button = document.createElement("button");
    button.type = "button";
    button.className = "scene-mode-button";
    button.textContent = label;
    button.addEventListener("click", () => setMode(value));
    modeButtons.set(value, button);
    modeToggle.appendChild(button);
  }
  const save = document.createElement("button");
  save.type = "button";
  save.className = "primary";
  save.addEventListener("click", () => void saveAll());
  toolbar.append(title, path, modeToggle, save);
  root.appendChild(toolbar);

  const body = document.createElement("div");
  body.className = "scene-body";

  const palette = document.createElement("div");
  palette.className = "scene-palette";
  body.appendChild(palette);

  const main = document.createElement("div");
  main.className = "scene-main";

  const wrap = document.createElement("div");
  wrap.className = "map-canvas-wrap";
  const canvas = document.createElement("canvas");
  canvas.width = options.mapModel.def.width * TILE_SIZE;
  canvas.height = options.mapModel.def.height * TILE_SIZE;
  wrap.appendChild(canvas);
  main.appendChild(wrap);

  const entityList = document.createElement("div");
  entityList.className = "scene-entity-list";
  const listTitle = document.createElement("h4");
  listTitle.textContent = "Entities";
  const listBody = document.createElement("div");
  listBody.className = "scene-entity-rows";
  entityList.append(listTitle, listBody);
  main.appendChild(entityList);

  body.appendChild(main);
  root.appendChild(body);

  function setMode(next: SceneEditorMode): void {
    mode = next;
    activePlacement = null;
    selectedIndex = null;
    for (const [value, button] of modeButtons) button.classList.toggle("selected", value === next);
    renderPalette();
    draw();
  }

  function setArm(placement: NonNullable<ActivePlacement>): void {
    activePlacement = placement;
    selectedIndex = null;
    renderPalette();
    renderEntityList();
    draw();
  }

  function setSelected(index: number | null): void {
    activePlacement = null;
    selectedIndex = index;
    renderPalette();
    renderEntityList();
    draw();
  }

  function renderPalette(): void {
    palette.replaceChildren();
    if (mode === "scene") renderScenePalette();
    else renderMapPalette();
  }

  function renderScenePalette(): void {
    const buildings = sectionHeader("Buildings");
    const buildingList = document.createElement("div");
    buildingList.className = "scene-palette-list";
    if (options.buildings.length === 0) {
      const none = document.createElement("span");
      none.className = "muted";
      none.textContent = "no building defs in the project";
      buildingList.appendChild(none);
    }
    for (const entry of options.buildings) {
      const button = document.createElement("button");
      button.type = "button";
      button.className = "scene-palette-item";
      const active = activePlacement !== null && activePlacement.type === "building" && activePlacement.id === entry.id;
      if (active) button.classList.add("selected");
      const badge = document.createElement("span");
      badge.className = "scene-palette-badge";
      badge.textContent = `${entry.footprint.w}×${entry.footprint.h}`;
      const label = document.createElement("span");
      label.textContent = entry.name ?? entry.id;
      button.title = `${entry.id} — ${entry.footprint.w}×${entry.footprint.h} footprint`;
      button.append(label, badge);
      button.addEventListener("click", () => setArm({ type: "building", id: entry.id }));
      buildingList.appendChild(button);
    }
    palette.append(buildings, buildingList);

    const animals = sectionHeader("Animals");
    const animalList = document.createElement("div");
    animalList.className = "scene-palette-list";
    if (options.animals.length === 0) {
      const none = document.createElement("span");
      none.className = "muted";
      none.textContent = "no animal defs in the project";
      animalList.appendChild(none);
    }
    for (const id of options.animals) {
      const button = document.createElement("button");
      button.type = "button";
      button.className = "scene-palette-item";
      if (activePlacement !== null && activePlacement.type === "animal" && activePlacement.id === id) button.classList.add("selected");
      const label = document.createElement("span");
      label.textContent = id;
      button.append(label);
      button.addEventListener("click", () => setArm({ type: "animal", id }));
      animalList.appendChild(button);
    }
    palette.append(animals, animalList);

    const npcSection = sectionHeader("NPC");
    const npcForm = document.createElement("div");
    npcForm.className = "scene-npc-form";
    const npcIdInput = document.createElement("input");
    npcIdInput.type = "text";
    npcIdInput.placeholder = "npc id";
    npcIdInput.spellcheck = false;
    const dialogueInput = document.createElement("input");
    dialogueInput.type = "text";
    dialogueInput.placeholder = "dialogue id (optional)";
    dialogueInput.spellcheck = false;
    const labelInput = document.createElement("input");
    labelInput.type = "text";
    labelInput.placeholder = "label (optional)";
    labelInput.spellcheck = false;
    const npcButton = document.createElement("button");
    npcButton.type = "button";
    npcButton.textContent = "Place NPC";
    npcButton.addEventListener("click", () => {
      const id = npcIdInput.value.trim();
      if (id === "") {
        options.onStatus("enter an npc id first", true);
        return;
      }
      setArm({ type: "npc", id });
      options.onStatus(`armed: place npc "${id}" on the map`);
    });
    npcForm.append(npcIdInput, dialogueInput, labelInput, npcButton);
    palette.append(npcSection, npcForm);
  }

  function renderMapPalette(): void {
    const tools = document.createElement("div");
    tools.className = "map-tools";
    const toolButtons = new Map<MapTool, HTMLButtonElement>();
    for (const tool of MAP_TOOLS) {
      const button = document.createElement("button");
      button.type = "button";
      button.className = "map-tool-button";
      button.textContent = tool.label;
      button.title = tool.title;
      button.addEventListener("click", () => {
        mapTool = tool.id === mapTool && tool.id === "walkable" ? "paint" : tool.id;
        renderPalette();
        draw();
      });
      toolButtons.set(tool.id, button);
      tools.appendChild(button);
    }
    for (const [id, button] of toolButtons) button.classList.toggle("selected", id === mapTool);
    palette.append(tools);

    const list = document.createElement("div");
    list.className = "palette-list";
    for (const id of options.mapModel.palette) {
      const swatch = document.createElement("button");
      swatch.type = "button";
      swatch.className = "palette-swatch";
      if (id === mapSelectedId && mapTool === "paint") swatch.classList.add("selected");
      const chip = document.createElement("span");
      chip.className = "swatch-chip";
      chip.style.background = tileColor(id);
      const label = document.createElement("span");
      label.className = "swatch-label";
      label.textContent = isWalkableTile(options.mapModel, id) ? id : `${id} (blocked)`;
      swatch.append(chip, label);
      swatch.addEventListener("click", () => {
        if (mapTool === "walkable") {
          toggleWalkable(options.mapModel, id);
          renderPalette();
          draw();
          updateSave();
        } else {
          mapSelectedId = id;
          renderPalette();
        }
      });
      list.appendChild(swatch);
    }
    palette.append(list);

    const addForm = document.createElement("form");
    addForm.className = "add-tile-form";
    const addInput = document.createElement("input");
    addInput.type = "text";
    addInput.placeholder = "tile id";
    const addButton = document.createElement("button");
    addButton.type = "submit";
    addButton.textContent = "Add";
    addForm.append(addInput, addButton);
    addForm.addEventListener("submit", (event) => {
      event.preventDefault();
      const value = addInput.value.trim();
      addInput.value = "";
      if (value !== "") {
        addTileId(options.mapModel, value);
        renderPalette();
      }
    });
    palette.append(addForm);
  }

  function renderEntityList(): void {
    listBody.replaceChildren();
    if (options.sceneModel.def.entities.length === 0) {
      const none = document.createElement("span");
      none.className = "muted";
      none.textContent = "no entities yet — pick from the palette and click the map";
      listBody.appendChild(none);
      return;
    }
    options.sceneModel.def.entities.forEach((entity, index) => {
      const row = document.createElement("div");
      row.className = "scene-entity-row";
      if (index === selectedIndex) row.classList.add("selected");
      const dot = document.createElement("span");
      dot.className = "scene-entity-dot";
      dot.style.background = entityColor(entity);
      const label = document.createElement("span");
      label.textContent = entityLabel(entity);
      label.title = describeEntity(entity);
      const coords = document.createElement("span");
      coords.className = "scene-entity-coords";
      coords.textContent = `(${entity.x},${entity.y})`;
      const removeButton = document.createElement("button");
      removeButton.type = "button";
      removeButton.className = "scene-entity-delete";
      removeButton.textContent = "×";
      removeButton.title = "Remove entity";
      removeButton.addEventListener("click", (event) => {
        event.stopPropagation();
        if (window.confirm(`Remove ${entityLabel(entity)}?`)) {
          const result = removeEntity(options.sceneModel, index);
          if (result.ok) {
            selectedIndex = null;
            options.onStatus(`removed ${entityLabel(entity)}`);
          } else {
            options.onStatus(result.reason, true);
          }
          renderEntityList();
          draw();
          updateSave();
        }
      });
      row.append(dot, label, coords, removeButton);
      row.addEventListener("click", () => setSelected(selectedIndex === index ? null : index));
      listBody.appendChild(row);
    });
  }

  function draw(): void {
    if (disposed) return;
    const ctx = canvas.getContext("2d");
    if (ctx === null) return;
    ctx.clearRect(0, 0, canvas.width, canvas.height);
    drawTiles(ctx);
    drawGrid(ctx);
    if (mode === "map") {
      if (mapTool === "walkable") drawBlocked(ctx);
      drawSpawn(ctx);
    }
    drawEntities(ctx);
  }

  function drawTiles(ctx: CanvasRenderingContext2D): void {
    const data = options.mapModel.def.layers[options.mapModel.groundIndex]?.data;
    for (let y = 0; y < options.mapModel.def.height; y++) {
      for (let x = 0; x < options.mapModel.def.width; x++) {
        const tile = data?.[y]?.[x] ?? "";
        ctx.fillStyle = tileColor(tile);
        ctx.fillRect(x * TILE_SIZE, y * TILE_SIZE, TILE_SIZE, TILE_SIZE);
      }
    }
  }

  function drawGrid(ctx: CanvasRenderingContext2D): void {
    ctx.strokeStyle = "rgba(10, 12, 16, 0.35)";
    ctx.lineWidth = 1;
    ctx.beginPath();
    for (let x = 0; x <= options.mapModel.def.width; x++) {
      ctx.moveTo(x * TILE_SIZE + 0.5, 0);
      ctx.lineTo(x * TILE_SIZE + 0.5, canvas.height);
    }
    for (let y = 0; y <= options.mapModel.def.height; y++) {
      ctx.moveTo(0, y * TILE_SIZE + 0.5);
      ctx.lineTo(canvas.width, y * TILE_SIZE + 0.5);
    }
    ctx.stroke();
  }

  function drawBlocked(ctx: CanvasRenderingContext2D): void {
    const data = options.mapModel.def.layers[options.mapModel.groundIndex]?.data;
    for (let y = 0; y < options.mapModel.def.height; y++) {
      for (let x = 0; x < options.mapModel.def.width; x++) {
        const tile = data?.[y]?.[x] ?? "";
        if (tile === "" || isWalkableTile(options.mapModel, tile)) continue;
        ctx.strokeStyle = "rgba(231, 76, 60, 0.9)";
        ctx.lineWidth = 2;
        const px = x * TILE_SIZE;
        const py = y * TILE_SIZE;
        ctx.beginPath();
        ctx.moveTo(px, py);
        ctx.lineTo(px + TILE_SIZE, py + TILE_SIZE);
        ctx.moveTo(px + TILE_SIZE, py);
        ctx.lineTo(px, py + TILE_SIZE);
        ctx.stroke();
      }
    }
  }

  function drawSpawn(ctx: CanvasRenderingContext2D): void {
    const sx = options.mapModel.def.spawn.x * TILE_SIZE + TILE_SIZE / 2;
    const sy = options.mapModel.def.spawn.y * TILE_SIZE + TILE_SIZE / 2;
    ctx.strokeStyle = "#ffd54f";
    ctx.fillStyle = "#ffd54f";
    ctx.lineWidth = 3;
    ctx.beginPath();
    ctx.arc(sx, sy, TILE_SIZE * 0.32, 0, Math.PI * 2);
    ctx.stroke();
    ctx.beginPath();
    ctx.arc(sx, sy, TILE_SIZE * 0.14, 0, Math.PI * 2);
    ctx.fill();
  }

  function drawEntities(ctx: CanvasRenderingContext2D): void {
    options.sceneModel.def.entities.forEach((entity, index) => {
      const footprint = entityFootprint(options.sceneModel, entity);
      const px = entity.x * TILE_SIZE;
      const py = entity.y * TILE_SIZE;
      if (entity.type === "building") {
        ctx.fillStyle = entityColor(entity);
        ctx.globalAlpha = 0.85;
        ctx.fillRect(px, py, footprint.w * TILE_SIZE, footprint.h * TILE_SIZE);
        ctx.globalAlpha = 1;
        ctx.strokeStyle = "rgba(10, 12, 16, 0.6)";
        ctx.lineWidth = 1;
        ctx.strokeRect(px + 0.5, py + 0.5, footprint.w * TILE_SIZE - 1, footprint.h * TILE_SIZE - 1);
        ctx.fillStyle = "#e6e9ec";
        ctx.font = "10px system-ui, sans-serif";
        ctx.fillText(entity.buildingId, px + 3, py + 12);
      } else {
        const cx = px + TILE_SIZE / 2;
        const cy = py + TILE_SIZE / 2;
        const radius = entity.type === "npc" ? TILE_SIZE * 0.3 : TILE_SIZE * 0.25;
        ctx.fillStyle = entityColor(entity);
        ctx.beginPath();
        ctx.arc(cx, cy, radius, 0, Math.PI * 2);
        ctx.fill();
        ctx.strokeStyle = "rgba(10, 12, 16, 0.6)";
        ctx.lineWidth = 1;
        ctx.stroke();
        ctx.fillStyle = "#e6e9ec";
        ctx.font = "10px system-ui, sans-serif";
        ctx.fillText(entity.type === "npc" ? entity.npcId : entity.animalId, px + 2, py + 24);
      }
      if (index === selectedIndex) {
        ctx.strokeStyle = SELECT_COLOR;
        ctx.lineWidth = 2;
        ctx.strokeRect(px - 1.5, py - 1.5, footprint.w * TILE_SIZE + 3, footprint.h * TILE_SIZE + 3);
      }
    });
  }

  function cellAt(event: MouseEvent): { x: number; y: number } {
    const rect = canvas.getBoundingClientRect();
    return pointToTile(event.clientX - rect.left, event.clientY - rect.top);
  }

  function applyPlacement(result: SceneOpResult, placed: string): void {
    if (result.ok) {
      const last = options.sceneModel.def.entities[options.sceneModel.def.entities.length - 1];
      const at = last !== undefined ? ` at (${last.x},${last.y})` : "";
      options.onStatus(`placed ${placed}${at}`);
    } else {
      options.onStatus(result.reason, true);
    }
    renderEntityList();
    draw();
    updateSave();
  }

  function applyMapAction(x: number, y: number): void {
    const model = options.mapModel;
    const paletteBefore = model.palette.join("\u0000");
    switch (mapTool) {
      case "paint":
        paint(model, x, y, mapSelectedId);
        break;
      case "erase":
        erase(model, x, y);
        break;
      case "spawn":
        setSpawn(model, x, y);
        break;
      case "walkable": {
        const tile = model.def.layers[model.groundIndex]?.data[y]?.[x] ?? "";
        if (tile !== "") toggleWalkable(model, tile);
        break;
      }
    }
    draw();
    if (mapTool === "walkable" || model.palette.join("\u0000") !== paletteBefore) renderPalette();
    updateSave();
  }

  function updateSave(): void {
    const dirty = options.sceneModel.dirty || options.mapModel.dirty;
    save.textContent = dirty ? "Save *" : "Save";
    save.disabled = !dirty;
  }

  async function saveAll(): Promise<void> {
    const saved: string[] = [];
    if (options.sceneModel.dirty) {
      const def = serializeScene(options.sceneModel);
      if (def === null) {
        options.onStatus(`${options.scenePath}: scene invalid — not saved`, true);
        return;
      }
      try {
        await window.nengine.project.writeYaml({ root: options.root, path: options.scenePath, content: stringify(def) });
        markSceneSaved(options.sceneModel);
        saved.push(options.scenePath);
      } catch (err) {
        options.onStatus(err instanceof Error ? err.message : String(err), true);
        return;
      }
    }
    if (options.mapModel.dirty) {
      const def = serializeMap(options.mapModel);
      if (def === null) {
        options.onStatus(`${options.mapPath}: map invalid — not saved`, true);
        return;
      }
      try {
        await window.nengine.project.writeYaml({ root: options.root, path: options.mapPath, content: stringify(def) });
        markMapSaved(options.mapModel);
        saved.push(options.mapPath);
      } catch (err) {
        options.onStatus(err instanceof Error ? err.message : String(err), true);
        return;
      }
    }
    if (saved.length > 0) {
      updateSave();
      options.onStatus(`saved ${saved.join(" · ")}`);
      options.onSaved?.();
    }
  }

  canvas.addEventListener("mousedown", (event) => {
    if (event.button === 2) {
      if (mode === "map") {
        const { x, y } = cellAt(event);
        erase(options.mapModel, x, y);
        draw();
        updateSave();
      }
      event.preventDefault();
      return;
    }
    if (event.button !== 0) return;
    const { x, y } = cellAt(event);
    if (mode === "map") {
      painting = true;
      applyMapAction(x, y);
      return;
    }
    if (activePlacement !== null) {
      if (activePlacement.type === "npc") {
        applyPlacement(addNpc(options.sceneModel, activePlacement.id, x, y), `npc "${activePlacement.id}"`);
      } else if (activePlacement.type === "building") {
        applyPlacement(addBuilding(options.sceneModel, activePlacement.id, x, y), `building "${activePlacement.id}"`);
      } else {
        applyPlacement(addAnimal(options.sceneModel, activePlacement.id, x, y), `animal "${activePlacement.id}"`);
      }
      return;
    }
    const index = entityIndexAt(options.sceneModel, x, y);
    if (selectedIndex !== null) {
      if (index === -1) {
        const entity = options.sceneModel.def.entities[selectedIndex];
        if (entity === undefined) return;
        const result = moveEntity(options.sceneModel, selectedIndex, x, y);
        if (result.ok) options.onStatus(`moved ${describeEntity(entity)} to (${x},${y})`);
        else options.onStatus(result.reason, true);
        renderEntityList();
        draw();
        updateSave();
        return;
      }
      if (index === selectedIndex) setSelected(null);
      else setSelected(index);
      return;
    }
    setSelected(index === -1 ? null : index);
  });
  canvas.addEventListener("mousemove", (event) => {
    if (mode !== "map" || !painting) return;
    const { x, y } = cellAt(event);
    applyMapAction(x, y);
  });
  canvas.addEventListener("mouseup", () => {
    painting = false;
  });
  canvas.addEventListener("mouseleave", () => {
    painting = false;
  });
  canvas.addEventListener("contextmenu", (event) => event.preventDefault());

  setMode("scene");
  renderEntityList();
  updateSave();

  if (options.onFlush !== undefined) {
    options.onFlush(() => {
      const flushes: PlaytestFlush[] = [];
      if (options.sceneModel.dirty) {
        const def = serializeScene(options.sceneModel);
        if (def === null) flushes.push({ path: options.scenePath, error: "scene invalid — not saved" });
        else flushes.push({ path: options.scenePath, content: stringify(def) });
      }
      if (options.mapModel.dirty) {
        const def = serializeMap(options.mapModel);
        if (def === null) flushes.push({ path: options.mapPath, error: "map invalid — not saved" });
        else flushes.push({ path: options.mapPath, content: stringify(def) });
      }
      return flushes;
    });
  }

  return () => {
    disposed = true;
  };
}

function sectionHeader(text: string): HTMLHeadingElement {
  const header = document.createElement("h4");
  header.className = "scene-palette-section";
  header.textContent = text;
  return header;
}

function entityLabel(entity: SceneEntity): string {
  if (entity.type === "building") return `building ${entity.buildingId}`;
  if (entity.type === "npc") return `npc ${entity.npcId}`;
  return `animal ${entity.animalId}`;
}