import { test } from 'node:test';
import assert from 'node:assert/strict';
import { readFileSync } from 'node:fs';
import { Mesh, MeshBasicMaterial, Raycaster, Vector3 } from 'three';
import { createTerrainGeometry, terrainGeometryHeightAt } from '../src/scene/terrainGeometry.ts';
import { applySummitTerrain } from '../src/scene/summitTerrain.ts';
import { SUMMIT_TERRAIN } from '../src/constants/summitTerrain.ts';
import { SUMMIT_PLATEAU } from '../src/constants/summitPlateau.ts';
import { structurePosition } from '../src/scene/structures.ts';
import { STRUCTURES } from '../src/constants/structures.ts';

const meta = JSON.parse(readFileSync(new URL('../public/terrain/gwanaksan.json', import.meta.url), 'utf8'));
const bytes = readFileSync(new URL('../public/terrain/gwanaksan.f32', import.meta.url));
const heights = new Float32Array(bytes.buffer.slice(bytes.byteOffset, bytes.byteOffset + bytes.byteLength));
const start = structurePosition(SUMMIT_TERRAIN.start.latitude, SUMMIT_TERRAIN.start.longitude, meta.origin);

test('authored terrain edges join the surrounding slope without vertical steps', () => {
  const geometry = createTerrainGeometry(meta, heights, true);
  applySummitTerrain(geometry, meta);
  const [left, top, right, bottom] = SUMMIT_PLATEAU.atlasBounds;
  const height = (x: number, z: number) => terrainGeometryHeightAt(geometry, start.x+x, start.z+z);
  try {
    // Scan across all four seams, including the last authored half-metre cell.
    for (const [edge, from, to, horizontal] of [
      [left, top, bottom, true], [right, top, bottom, true],
      [top, left, right, false], [bottom, left, right, false],
    ] as const) {
      for (let along = from; along <= to; along += .5) {
        for (let offset = -1; offset < 1; offset += .25) {
          const a = horizontal ? height(edge+offset, along) : height(along, edge+offset);
          const b = horizontal ? height(edge+offset+.25, along) : height(along, edge+offset+.25);
          assert.ok(Math.abs(b-a) < .5, `terrain seam at ${edge}, ${along}: ${Math.abs(b-a)}m step over 0.25m`);
        }
      }
    }
  } finally {
    geometry.dispose();
  }
});

test('local reconstruction preserves source data and every vertex outside 200m', () => {
  const geometry = createTerrainGeometry(meta, heights, true);
  const p = geometry.getAttribute('position');
  const before = p.array.slice();
  const source = heights.slice();
  applySummitTerrain(geometry, meta);
  let changed = 0;
  for (let i=0; i<p.count; i++) {
    const distance = Math.hypot(p.getX(i)-start.x, p.getZ(i)-start.z);
    if (distance >= 200) assert.equal(p.getY(i), before[i*3+1]);
    if (p.getY(i) !== before[i*3+1]) changed++;
  }
  assert.ok(changed > 100);
  assert.deepEqual(heights, source);
  geometry.dispose();
});

test('radar building and dome clear the saddle from the estimated eye position', () => {
  const geometry = createTerrainGeometry(meta, heights, true);
  applySummitTerrain(geometry, meta);
  const ground = terrainGeometryHeightAt(geometry,start.x,start.z);
  assert.ok(Math.abs(ground + meta.observerSurfaceElevation - 620) < 1);
  const radar = structurePosition(STRUCTURES.radar.latitude,STRUCTURES.radar.longitude,meta.origin);
  radar.y = terrainGeometryHeightAt(geometry,radar.x,radar.z) + 7;
  const eye = new Vector3(start.x,ground+1.7,start.z);
  assert.ok(radar.y > eye.y + 8, 'radar must stand above observer on its rock');
  const material = new MeshBasicMaterial();
  const mesh = new Mesh(geometry,material);
  const ray = new Raycaster(eye,radar.clone().sub(eye).normalize(),0,eye.distanceTo(radar));
  assert.equal(ray.intersectObject(mesh).length,0,'ridge must not hide radar building');
  for (const [x,z] of [[start.x,start.z],[radar.x,radar.z],[0,65],[start.x+199,start.z],
    [start.x-12,start.z-22],[start.x-2,start.z-45],[start.x+5,start.z-35],
    [start.x-9,start.z-12],[start.x-9,start.z-11],[start.x-9,start.z-13]]) {
    const hit = new Raycaster(new Vector3(x,1000,z),new Vector3(0,-1,0)).intersectObject(mesh)[0];
    assert.ok(Math.abs(hit.point.y-terrainGeometryHeightAt(geometry,x,z))<1e-4);
  }
  const joint = terrainGeometryHeightAt(geometry,start.x-9,start.z-12);
  const shoulders = (terrainGeometryHeightAt(geometry,start.x-9,start.z-11)
    + terrainGeometryHeightAt(geometry,start.x-9,start.z-13))/2;
  assert.ok(shoulders-joint>.15,'large fracture must be a physical depression, not only a painted line');
  geometry.dispose(); material.dispose();
});