import * as THREE from 'three';
import type { App, View } from '../core/app';
import { audio } from '../core/audio';
import { INGREDIENTS, type Ingredient, type IngredientId } from '../sim/ingredients';
import {
  aimCut,
  beginBite,
  cutFrame,
  cvWord,
  liftKnife,
  newCutSession,
  pieceCV,
  pieceVolumes,
  plannedCuts,
  type CutPattern,
  type CutSession,
} from '../sim/cutting';
import { Mess } from '../sim/mess';
import { makeCutleryMesh, TOOLS, type ToolId } from '../sim/cutlery';
import type { PrepResult } from '../game/judging';
import { el, Panel } from '../ui/hud';
import { Rng } from '../core/rng';
import { loadProp } from './assets';

const BOARD_Y = 0.06;
const BOARD_W = 4.6;
const BOARD_D = 2.4;

/**
 * The prep bench. One board, one knife, one ingredient at a time, and a mess
 * field that remembers everything you did to all three.
 *
 * Controls mirror the slicer on purpose: horizontal mouse aims the cut, press
 * bites, vertical strokes saw. The two new verbs are the ingredient's, not
 * yours: slippery skin skates if you lean without sawing, and wet flesh
 * juices the board. Drag on the empty board (off the ingredient) to wipe.
 */
export class PrepView implements View {
  readonly root = new THREE.Group();
  readonly mess = new Mess(96);

  private session: CutSession | null = null;
  private ing!: Ingredient;
  private ingMesh: THREE.Group | null = null;
  private pieces: THREE.Group | null = null;
  private seams: THREE.Mesh[] = [];
  private knifeMesh!: THREE.Group;
  private rng = new Rng(20260717);

  private messTexData: Uint8Array;
  private messTex: THREE.DataTexture;
  private messVersion = -1;
  private solidsMesh: THREE.InstancedMesh;

  private ray = new THREE.Raycaster();
  private planePt = new THREE.Vector3();
  private plane = new THREE.Plane(new THREE.Vector3(0, 0, 1), 0.2);
  private boardPlane = new THREE.Plane(new THREE.Vector3(0, 1, 0), -(BOARD_Y * 2));
  private prev = new THREE.Vector2();
  private hasPrev = false;
  private wipePrev: THREE.Vector3 | null = null;
  private sawPhase = 0;
  private doneTimer = 0;

  private panel: Panel;
  private askEl!: HTMLElement;
  private cutsEl!: HTMLElement;
  private progFill!: HTMLElement;
  private benchEl!: HTMLElement;
  private hintEl!: HTMLElement;

  onDone: ((result: PrepResult) => void) | null = null;

  constructor(private app: App) {
    this.buildScenery();
    const n = this.mess.field.n;
    this.messTexData = new Uint8Array(n * n * 4);
    this.messTex = new THREE.DataTexture(this.messTexData, n, n, THREE.RGBAFormat);
    this.messTex.minFilter = THREE.LinearFilter;
    this.messTex.magFilter = THREE.LinearFilter;
    const stain = new THREE.Mesh(
      new THREE.PlaneGeometry(BOARD_W, BOARD_D),
      new THREE.MeshBasicMaterial({ map: this.messTex, transparent: true, depthWrite: false }),
    );
    stain.rotation.x = -Math.PI / 2;
    stain.position.y = BOARD_Y * 2 + 0.004;
    this.root.add(stain);

    // Solids: seeds and skins, instanced like the rind bits.
    const seedGeo = new THREE.SphereGeometry(0.028, 8, 6);
    seedGeo.scale(1, 0.45, 0.72);
    this.solidsMesh = new THREE.InstancedMesh(
      seedGeo,
      new THREE.MeshStandardMaterial({ color: 0xf0e6c8, roughness: 0.6 }),
      256,
    );
    this.solidsMesh.count = 0;
    this.solidsMesh.castShadow = true;
    this.root.add(this.solidsMesh);

    this.panel = new Panel('prep-panel');
    this.buildUi();
    this.panel.hide();
  }

  private buildUi(): void {
    const p = this.panel.root;
    const card = el('div', 'slicer-card', p);
    el('div', 'drawer-lbl', card, 'PREP IT');
    this.askEl = el('div', 'slicer-ask', card, '');
    this.cutsEl = el('div', 'slicer-thick', card, '');
    const bar = el('div', 'timer-bar', card);
    this.progFill = el('div', 'timer-fill', bar);
    this.benchEl = el('div', 'slicer-wobble', card, '');
    this.hintEl = el('div', 'drawer-hint', p, '');
  }

  private buildScenery(): void {
    const bench = new THREE.Mesh(
      new THREE.BoxGeometry(24, 0.4, 12),
      new THREE.MeshStandardMaterial({ color: 0x4a3524, roughness: 0.85 }),
    );
    bench.position.y = -0.2;
    bench.receiveShadow = true;
    this.root.add(bench);
    const board = new THREE.Mesh(
      new THREE.BoxGeometry(BOARD_W, BOARD_Y * 2, BOARD_D),
      new THREE.MeshStandardMaterial({ color: 0xa87c4f, roughness: 0.7 }),
    );
    board.position.y = BOARD_Y;
    board.receiveShadow = true;
    board.castShadow = true;
    this.root.add(board);
    void loadProp('/assets/models/cutting_board.glb', 2.2)
      .then((prop) => {
        prop.position.y = BOARD_Y;
        board.visible = false;
        this.root.add(prop);
      })
      .catch(() => undefined);
  }

  /** Procedural stand-in silhouettes — the shapes carry the physics. */
  private buildIngredientMesh(ing: Ingredient): THREE.Group {
    const g = new THREE.Group();
    const skin = new THREE.MeshStandardMaterial({
      color: new THREE.Color().setRGB(...ing.colors.skin, THREE.SRGBColorSpace),
      roughness: 0.55,
    });
    let mesh: THREE.Mesh;
    const r = ing.size / 2;
    switch (ing.shape) {
      case 'ovoid': {
        mesh = new THREE.Mesh(new THREE.SphereGeometry(r, 28, 20), skin);
        mesh.scale.set(1.25, 0.92, 0.92);
        break;
      }
      case 'block': {
        mesh = new THREE.Mesh(new THREE.BoxGeometry(ing.size, ing.size * 0.6, ing.size * 0.7), skin);
        break;
      }
      case 'wedge': {
        mesh = new THREE.Mesh(new THREE.CylinderGeometry(r, r, ing.size * 0.5, 24, 1, false, 0, Math.PI / 2.2), skin);
        mesh.rotation.y = Math.PI / 4;
        break;
      }
      case 'bulb': {
        mesh = new THREE.Mesh(new THREE.SphereGeometry(r, 20, 14), skin);
        mesh.scale.set(1, 0.85, 1);
        break;
      }
      default:
        mesh = new THREE.Mesh(new THREE.SphereGeometry(r, 28, 20), skin);
    }
    mesh.castShadow = true;
    mesh.receiveShadow = true;
    g.add(mesh);
    g.position.y = BOARD_Y * 2 + (ing.shape === 'block' ? ing.size * 0.3 : r * (ing.shape === 'bulb' ? 0.85 : 0.92));
    return g;
  }

  /** A fresh ingredient and a fresh session. */
  reset(ingredientId: IngredientId, knife: ToolId, pattern: CutPattern, askText: string): void {
    this.ing = INGREDIENTS[ingredientId];
    this.session = newCutSession(this.ing, knife, pattern);
    if (this.ingMesh) this.root.remove(this.ingMesh);
    if (this.pieces) this.root.remove(this.pieces);
    this.pieces = null;
    for (const s of this.seams) this.root.remove(s);
    this.seams = [];
    this.ingMesh = this.buildIngredientMesh(this.ing);
    this.root.add(this.ingMesh);
    if (this.knifeMesh) this.root.remove(this.knifeMesh);
    this.knifeMesh = makeCutleryMesh(TOOLS[knife]);
    this.root.add(this.knifeMesh);
    this.mess.reset();
    this.askEl.textContent = askText;
    this.doneTimer = 0;
    this.hasPrev = false;
    this.wipePrev = null;
    this.hintEl.textContent = 'aim · press on it and saw up-down · drag the board to wipe';
  }

  enter(): void {
    this.panel.show();
  }
  exit(): void {
    this.panel.hide();
  }

  /** Board-local UV under the pointer, if the ray hits the board. */
  private boardUV(): { u: number; v: number } | null {
    const pt = new THREE.Vector3();
    if (!this.ray.ray.intersectPlane(this.boardPlane, pt)) return null;
    const u = (pt.x + BOARD_W / 2) / BOARD_W;
    const v = (pt.z + BOARD_D / 2) / BOARD_D;
    if (u < 0 || u > 1 || v < 0 || v > 1) return null;
    return { u, v };
  }

  update(dt: number): void {
    const inp = this.app.input;
    this.app.camera.position.set(1.2, 2.3, 4.4);
    this.app.camera.lookAt(0.6, 0.5, -0.1);
    const s = this.session;
    if (!s) return;

    this.ray.setFromCamera(inp.ndc, this.app.camera);
    this.plane.set(new THREE.Vector3(0, 0, 1), 0.2);
    const hit = this.ray.ray.intersectPlane(this.plane, this.planePt);

    // Cutting happens on the vertical plane near the ingredient; wiping on the
    // board everywhere else. "Near" = within a size of the centre.
    const nearIngredient = hit && Math.abs(this.planePt.x) < this.ing.size * 0.85 && s.phase !== 'done';

    if (s.phase !== 'done' && nearIngredient && hit) {
      if (s.phase === 'aim') {
        aimCut(s, this.planePt.x / this.ing.size);
        if (inp.down) {
          beginBite(s);
          audio.clatter(0.15, 1.8);
        }
      } else if (inp.down && this.hasPrev) {
        const dy = this.planePt.y - this.prev.y;
        const dx = this.planePt.x - this.prev.x;
        const f = cutFrame(s, dy, dx, dt, () => this.rng.next());
        if (Math.abs(dy) > 0.004) {
          this.sawPhase += Math.abs(dy) * 3;
          audio.scrape(0.4, (Math.abs(dy) / Math.max(dt, 1e-3)) * 0.22);
        }
        this.applyFrame(f, dy);
      } else if (!inp.down) {
        liftKnife(s);
      }
    } else if (inp.down) {
      // Off the ingredient with the button down: the cloth.
      const uv = this.boardUV();
      if (uv && this.wipePrev) {
        this.mess.wipe(this.wipePrev.x, this.wipePrev.y, uv.u, uv.v);
      }
      if (uv) this.wipePrev = new THREE.Vector3(uv.u, uv.v, 0);
    }
    if (!inp.down) this.wipePrev = null;

    if (s.phase === 'done') {
      this.doneTimer += dt;
      // No auto-exit: the bench is judged at serve, so the moment after the
      // last cut is exactly when you'd want the cloth. ENTER hands it over.
      this.hintEl.textContent = 'done — wipe the board if you dare care · ENTER takes it to the kitchen';
      if (inp.justPressed('Enter') && this.onDone) {
        const result = this.result();
        const cb = this.onDone;
        this.onDone = null;
        cb(result);
        return;
      }
    }

    this.prev.set(this.planePt.x, this.planePt.y);
    this.hasPrev = !!hit;
    this.positionKnife(s);
    this.syncMess();
    this.updateHud(s);
  }

  /** What the judge reads. Snapshot at any time; final after onDone. */
  result(): PrepResult {
    const s = this.session!;
    return {
      cv: pieceCV(s),
      pieces: pieceVolumes(s).length,
      patternName: s.pattern.kind === 'halve' ? 'halves' : s.pattern.kind,
      slips: s.slips,
      bench: this.mess.stats(),
    };
  }

  private applyFrame(f: ReturnType<typeof cutFrame>, dy: number): void {
    const s = this.session!;
    const cutWorldX = s.aimPos * this.ing.size;
    const u = (cutWorldX + BOARD_W / 2) / BOARD_W;
    const v = 0.5;
    if (f.juice > 0) {
      // Sprayed along the blade (board Z), the side picked by the stroke.
      const side = dy > 0 ? 1 : -1;
      this.mess.addJuice(u, v, f.juice, (this.rng.next() - 0.5) * 0.3, side * (0.6 + this.rng.next() * 0.4));
    }
    if (f.slipped) {
      audio.clatter(0.5, 0.9);
      this.app.shake = 0.015;
      this.hintEl.textContent = 'it skated. saw as you press — the blade needs to bite';
    }
    if (f.cutDone) {
      audio.clunk(false);
      this.addSeam(s.cuts[s.cuts.length - 1]);
      for (let i = 0; i < f.seedsSpilled; i++) {
        this.mess.addSolid(u + (this.rng.next() - 0.5) * 0.12, v + (this.rng.next() - 0.5) * 0.3, 'seed');
      }
    }
    if (f.sessionDone) {
      this.showPieces();
    }
  }

  /** Committed cuts read as dark seams on the ingredient. */
  private addSeam(pos: number): void {
    const seam = new THREE.Mesh(
      new THREE.BoxGeometry(0.016, this.ing.size * 0.95, this.ing.size * 0.95),
      new THREE.MeshStandardMaterial({
        color: new THREE.Color().setRGB(
          this.ing.colors.flesh[0] * 0.45,
          this.ing.colors.flesh[1] * 0.45,
          this.ing.colors.flesh[2] * 0.45,
          THREE.SRGBColorSpace,
        ),
        roughness: 1,
      }),
    );
    seam.position.set(pos * this.ing.size, this.ingMesh!.position.y, 0);
    this.root.add(seam);
    this.seams.push(seam);
  }

  /** Session done: the whole becomes pieces, fanned apart so the CV is visible. */
  private showPieces(): void {
    if (!this.session || this.pieces) return;
    const s = this.session;
    if (this.ingMesh) this.ingMesh.visible = false;
    for (const seam of this.seams) this.root.remove(seam);
    this.seams = [];
    this.pieces = new THREE.Group();
    const flesh = new THREE.MeshStandardMaterial({
      color: new THREE.Color().setRGB(...this.ing.colors.flesh, THREE.SRGBColorSpace),
      roughness: 0.5,
    });
    const edges = [-0.5, ...[...s.cuts].sort((a, b) => a - b), 0.5];
    let x = -this.ing.size * 0.55 - edges.length * 0.02;
    for (let i = 0; i + 1 < edges.length; i++) {
      const w = (edges[i + 1] - edges[i]) * this.ing.size;
      const mid = (edges[i] + edges[i + 1]) / 2;
      const rHere = Math.sqrt(Math.max(0.05, 0.25 - mid * mid)) * this.ing.size;
      const piece = new THREE.Mesh(new THREE.CylinderGeometry(rHere, rHere, Math.max(0.02, w * 0.92), 20), flesh);
      piece.rotation.z = Math.PI / 2;
      piece.castShadow = true;
      piece.position.set(x + w / 2, BOARD_Y * 2 + rHere, 0.1);
      this.pieces.add(piece);
      x += w + 0.05;
    }
    this.root.add(this.pieces);
  }

  private positionKnife(s: CutSession): void {
    if (!this.knifeMesh) return;
    const topY = this.ingMesh ? this.ingMesh.position.y + this.ing.size * 0.55 : 1;
    this.knifeMesh.rotation.set(0, Math.PI / 2, Math.PI / 2);
    const sawZ = s.phase === 'saw' ? Math.sin(this.sawPhase * 6) * 0.3 : 0.15;
    const sink = s.phase === 'aim' || s.phase === 'done' ? 0 : s.progress * this.ing.size * 0.9;
    this.knifeMesh.visible = s.phase !== 'done';
    this.knifeMesh.position.set(s.aimPos * this.ing.size, topY + 0.22 - sink, sawZ + 0.35);
  }

  /** Push the mess field into the stain texture when it changed. */
  private syncMess(): void {
    if (this.mess.version === this.messVersion) return;
    this.messVersion = this.mess.version;
    const d = this.mess.field.data;
    const px = this.messTexData;
    for (let i = 0; i < d.length; i++) {
      const m = Math.min(1, d[i] * 2.2);
      px[i * 4] = 190;
      px[i * 4 + 1] = 68;
      px[i * 4 + 2] = 36;
      px[i * 4 + 3] = Math.round(Math.min(0.85, m) * 255);
    }
    this.messTex.needsUpdate = true;
    const solids = this.mess.solids.filter((s) => !s.collected);
    const mat = new THREE.Matrix4();
    let n = 0;
    for (const s of solids) {
      if (n >= 256) break;
      mat.setPosition(s.u * BOARD_W - BOARD_W / 2, BOARD_Y * 2 + 0.02, s.v * BOARD_D - BOARD_D / 2);
      this.solidsMesh.setMatrixAt(n++, mat);
    }
    this.solidsMesh.count = n;
    this.solidsMesh.instanceMatrix.needsUpdate = true;
  }

  private updateHud(s: CutSession): void {
    const total = plannedCuts(s.pattern);
    const done = s.cuts.length + s.diceCutsA.length;
    if (s.phase === 'done') {
      const cv = pieceCV(s);
      this.cutsEl.textContent = `${pieceVolumes(s).length} pieces — CV ${cv.toFixed(3)}, ${cvWord(cv)}`;
    } else {
      this.cutsEl.textContent = `cut ${Math.min(done + 1, total)} of ${total}${s.phase === 'aim' ? ' (aiming)' : ''}`;
    }
    this.progFill.style.width = `${Math.round(s.progress * 100)}%`;
    this.progFill.style.background = '#e8a53a';
    const bench = this.mess.benchWord();
    const wobble =
      s.phase === 'saw' && s.wedge > 0.12 ? (s.wedge > 0.3 ? ' · that cut is wandering' : ' · drifting…') : '';
    this.benchEl.textContent = `bench: ${bench}${wobble}${s.slips ? ` · slips: ${s.slips}` : ''}`;
    this.benchEl.style.color = bench === 'clean' ? '' : bench === 'smeared' ? '#e8a53a' : '#e2603a';
  }

  dispose(): void {
    this.panel.dispose();
  }
}