/**
 * Lane A selftests — contracts, yard layout, anchors, phase machine.
 * Lane A owns this file. Other lanes: yours is js/tests/<letter>.test.js.
 */

import * as THREE from '../../vendor/three.module.js';
import { FIXED_DT, STORM_LEN, YARD, checkContract, createStubWind } from '../contracts.js';
import { createWorld, heightAt } from '../world.js';
import { createCameraRig } from '../camera.js';
import { createGame } from '../main.js';
import { assert, assertEq, assertLess, fixedLoop } from '../testkit.js';

/** @param {import('../testkit.js').Suite} t */
export default function run(t) {
  const scene = new THREE.Scene();
  const world = createWorld(scene, { wind: createStubWind({ calm: true }) });

  // --- contract conformance ------------------------------------------------
  // These are the merge tripwires: if a lane's module drifts from contracts.js,
  // this is where we find out, not three lanes later.

  t.test('contract: stub wind conforms', () => {
    assertEq(checkContract('wind', createStubWind()).join('; '), '');
  });

  t.test('contract: world conforms', () => {
    assertEq(checkContract('world', world).join('; '), '');
  });

  t.test('contract: camera rig conforms', () => {
    const rig = createCameraRig(document.createElement('div'));
    assertEq(checkContract('camera', rig).join('; '), '');
  });

  t.test('contract: game conforms', () => {
    assertEq(checkContract('game', createGame()).join('; '), '');
  });

  // --- camera --------------------------------------------------------------

  t.test('camera keeps a clear line to the player from every angle', () => {
    // PLAN3D §5-A acceptance: "camera never clips through house". Stated here
    // as the underlying invariant — no solid between the player's head and the
    // camera — so it still means something after Lane E swaps the graybox house
    // for house_yardside.glb.
    const rig = createCameraRig(document.createElement('div'));
    rig.setSolids(world.solids);
    rig.setGround(heightAt);
    const ray = new THREE.Raycaster();
    const head = new THREE.Vector3();

    const spots = [
      [0, -9.4],      // backed against the house — the case that caught it
      [-5, -9.2],     // under a fascia anchor
      [-9, 2.6],      // hard against a tree trunk
      [-6, 7],        // hard against a post
      [0, 9.2],       // against the south fence
    ];
    for (const [x, z] of spots) {
      const spot = new THREE.Vector3(x, heightAt(x, z), z);
      for (let k = 0; k < 6; k++) {
        rig.yaw = (k / 6) * Math.PI * 2;
        // 60 steps = 1 s of smoothing at lambda 9, i.e. 99.99% settled. Every
        // step is a raycast against the whole yard, so this bound is the
        // difference between a 1 s selftest and a 4 s one — and every lane runs
        // it after every merge.
        for (let i = 0; i < 60; i++) rig.update(1 / 60, spot);

        head.set(spot.x, spot.y + 1.55, spot.z);
        const cam = rig.object.position;
        const d = head.distanceTo(cam);
        assert(d > 0.1, `camera collapsed onto the player (${d.toFixed(3)}m) at (${x},${z})`);

        ray.set(head, cam.clone().sub(head).divideScalar(d));
        ray.far = d - 0.02;
        const blocked = ray.intersectObjects(world.solids, true)[0];
        assert(
          !blocked,
          `'${blocked?.object.name || '?'}' sits between the player at (${x},${z}) ` +
          `and the camera at yaw ${rig.yaw.toFixed(2)}`,
        );

        // The ground isn't a solid (heightAt handles it), so the raycast above
        // can't speak for it — assert it separately.
        assert(
          cam.y > heightAt(cam.x, cam.z),
          `camera is underground at (${cam.x.toFixed(1)},${cam.z.toFixed(1)}), ` +
          `y=${cam.y.toFixed(2)} vs terrain ${heightAt(cam.x, cam.z).toFixed(2)}`,
        );
      }
    }
  });

  // --- terrain -------------------------------------------------------------

  t.test('heightAt is pure and gentle across the whole yard', () => {
    for (let x = -15; x <= 15; x += 1.5) {
      for (let z = -10; z <= 10; z += 1.5) {
        const h = heightAt(x, z);
        assertEq(h, heightAt(x, z), `heightAt(${x},${z}) not pure`);
        assert(Math.abs(h) < 0.5, `heightAt(${x},${z}) = ${h}: terrain should stay gentle`);
      }
    }
  });

  t.test('garden bed sits inside the yard', () => {
    const b = world.gardenBed;
    assert(Math.abs(b.x) + b.w / 2 < YARD.width / 2, 'bed overhangs east/west');
    assert(Math.abs(b.z) + b.d / 2 < YARD.depth / 2, 'bed overhangs north/south');
  });

  // --- anchors -------------------------------------------------------------

  t.test('yard offers 7 anchors: 3 house, 2 tree, 2 post', () => {
    const by = (type) => world.anchors.filter((a) => a.type === type).length;
    assertEq(by('house'), 3, 'house anchors');
    assertEq(by('tree'), 2, 'tree anchors');
    assertEq(by('post'), 2, 'post anchors');
    const ids = world.anchors.map((a) => a.id);
    assertEq(new Set(ids).size, ids.length, `anchor ids not unique: ${ids}`);
  });

  t.test('sway() returns an absolute position, not an offset', () => {
    // If sway ever regresses to returning an offset, the returned point lands
    // near the origin instead of near the anchor, and Lane B's cloth corners
    // all snap to the middle of the yard. Catch it here.
    for (const a of world.anchors) {
      const p = a.sway(3.1);
      assertLess(p.distanceTo(a.pos), 0.6, `${a.id}.sway() is ${p.length().toFixed(2)}m from origin but should be near pos`);
    }
  });

  t.test('house and post anchors are rigid; tree anchors move', () => {
    for (const a of world.anchors.filter((x) => x.type !== 'tree')) {
      assertEq(a.sway(0).distanceTo(a.sway(12.5)), 0, `${a.id} should not move`);
    }
    for (const a of world.anchors.filter((x) => x.type === 'tree')) {
      // Sampled at two times a half-period apart; a static tree would score 0.
      const spread = a.sway(0).clone().distanceTo(a.sway(0.83));
      assert(spread > 1e-4, `${a.id} should sway with the wind, moved ${spread}m`);
    }
  });

  t.test('anchors do not alias each other scratch vectors', () => {
    // Two tree anchors handing out the same scratch Vector3 would silently
    // corrupt whichever corner was read first.
    const t1 = world.anchor('t1'), t2 = world.anchor('t2');
    const p1 = t1.sway(2);
    const x1 = p1.x;
    const p2 = t2.sway(2);
    assert(p1 !== p2, 't1 and t2 handed out the same vector object');
    assertEq(p1.x, x1, 'reading t2 mutated the vector t1 returned');
  });

  // --- wind stub -----------------------------------------------------------

  t.test('gust telegraph always gives at least 1.2 s of warning', () => {
    // The promise the whole storm rests on: the player can always react.
    // Lane C must keep this true for the real weather.js.
    const wind = createStubWind({ seed: 7 });
    let had = false, edges = 0;
    fixedLoop(STORM_LEN, FIXED_DT, (dt, time) => {
      const tel = wind.gustTelegraph(time);
      if (tel && !had) {
        edges++;
        assert(tel.eta >= 1.2, `telegraph appeared with only ${tel.eta.toFixed(2)}s of warning`);
      }
      had = !!tel;
    });
    assert(edges >= 5, `only ${edges} gusts telegraphed in a ${STORM_LEN}s storm — too quiet to test`);
  });

  t.test('wind stub is deterministic: same seed, same storm', () => {
    const a = createStubWind({ seed: 42 });
    const b = createStubWind({ seed: 42 });
    const p = new THREE.Vector3(1, 1, 1);
    for (let time = 0; time < STORM_LEN; time += 0.37) {
      const va = a.sample(p, time).clone();
      const vb = b.sample(p, time);
      assertEq(va.x, vb.x, `x diverged at t=${time}`);
      assertEq(va.z, vb.z, `z diverged at t=${time}`);
    }
  });

  t.test('wind stub gets angrier as the storm runs', () => {
    const wind = createStubWind({ seed: 3 });
    const p = new THREE.Vector3();
    assertLess(wind.sample(p, 1).length(), wind.sample(p, STORM_LEN - 1).length());
  });

  // --- phase machine -------------------------------------------------------

  t.test('phases cycle forecast → prep → storm → aftermath → forecast', () => {
    const game = createGame();
    assertEq(game.phase, 'forecast');
    game.advance(); assertEq(game.phase, 'prep');
    game.advance(); assertEq(game.phase, 'storm');
    game.advance(); assertEq(game.phase, 'aftermath');
    game.advance(); assertEq(game.phase, 'forecast');
  });

  t.test('phaseChange fires once, with from and to', () => {
    const game = createGame();
    const seen = [];
    game.on('phaseChange', (p) => seen.push(p));
    game.setPhase('prep');
    game.setPhase('prep');   // no-op: already there
    assertEq(seen.length, 1, 'phaseChange fired for a no-op transition');
    assertEq(seen[0].from, 'forecast');
    assertEq(seen[0].to, 'prep');
  });

  t.test('a 90 s storm ends itself (fast-forwarded, no rAF)', () => {
    const game = createGame();
    game.setPhase('storm');
    fixedLoop(STORM_LEN - 1, FIXED_DT, () => game.tick(FIXED_DT));
    assertEq(game.phase, 'storm', 'storm ended early');
    fixedLoop(2, FIXED_DT, () => game.tick(FIXED_DT));
    assertEq(game.phase, 'aftermath', 'storm never ended');
  });

  t.test('unknown phase is rejected', () => {
    const game = createGame();
    let threw = false;
    try { game.setPhase('apocalypse'); } catch { threw = true; }
    assert(threw, 'setPhase accepted a phase that does not exist');
  });
}