import { describe, it, expect } from 'vitest';
import biomeDataArray from '../src/data/biomes.json';
import { createSeededNoise, sampleNoise } from '../src/world/noise';
import { generateWorld } from '../src/world/generator';
import type { BiomeData } from '../src/world/types';

// Load the first biome — structural compatibility with BiomeData
const biome = biomeDataArray[0] as BiomeData;

// ─── Noise ──────────────────────────────────────────────────────

describe('Seeded Noise', () => {
  it('is deterministic with same seed', () => {
    const n1 = createSeededNoise(42);
    const n2 = createSeededNoise(42);
    expect(n1(0.5, 0.5)).toBe(n2(0.5, 0.5));
  });

  it('produces different results with different seeds', () => {
    const n1 = createSeededNoise(42);
    const n2 = createSeededNoise(99);
    expect(n1(0.5, 0.5)).not.toBe(n2(0.5, 0.5));
  });

  it('normalizes to [0, 1] via sampleNoise', () => {
    const noise = createSeededNoise(42);
    for (let i = 0; i < 200; i++) {
      const val = sampleNoise(noise, i * 0.3, i * 0.7, 0.1);
      expect(val).toBeGreaterThanOrEqual(0);
      expect(val).toBeLessThanOrEqual(1);
    }
  });

  it('varies across coordinates', () => {
    const noise = createSeededNoise(42);
    const values = new Set<number>();
    for (let i = 0; i < 50; i++) {
      values.add(sampleNoise(noise, i, 0, 0.1));
    }
    // Should have significant variety (not all same value)
    expect(values.size).toBeGreaterThan(20);
  });
});

// ─── Biome Data ─────────────────────────────────────────────────

describe('Biome Data', () => {
  it('has valid structure', () => {
    expect(biome.id).toBe('catalytic-wastes');
    expect(biome.tileSize).toBe(32);
    expect(biome.mapWidth).toBe(80);
    expect(biome.mapHeight).toBe(80);
  });

  it('has 8 tile types', () => {
    expect(biome.tiles).toHaveLength(8);
  });

  it('tile IDs are sequential starting from 0', () => {
    biome.tiles.forEach((tile, index) => {
      expect(tile.id).toBe(index);
    });
  });

  it('has both walkable and non-walkable tiles', () => {
    const walkable = biome.tiles.filter(t => t.walkable);
    const blocked = biome.tiles.filter(t => !t.walkable);
    expect(walkable.length).toBeGreaterThan(0);
    expect(blocked.length).toBeGreaterThan(0);
  });

  it('elevation rules cover full [0, 1] range', () => {
    const rules = biome.generation.elevationRules;
    expect(rules.length).toBeGreaterThan(0);
    // Last rule should cover up to 1.0
    expect(rules[rules.length - 1].below).toBe(1);
    // Rules should be sorted ascending
    for (let i = 1; i < rules.length; i++) {
      expect(rules[i].below).toBeGreaterThan(rules[i - 1].below);
    }
  });

  it('all elevation rule tileIds reference valid tiles', () => {
    const validIds = new Set(biome.tiles.map(t => t.id));
    for (const rule of biome.generation.elevationRules) {
      expect(validIds.has(rule.tileId)).toBe(true);
    }
  });
});

// ─── World Generation ───────────────────────────────────────────

describe('World Generation', () => {
  it('generates grid with correct dimensions', () => {
    const world = generateWorld(biome, 42);
    expect(world.grid).toHaveLength(biome.mapHeight);
    for (const row of world.grid) {
      expect(row).toHaveLength(biome.mapWidth);
    }
  });

  it('all tile IDs in grid are valid', () => {
    const world = generateWorld(biome, 42);
    const validIds = new Set(biome.tiles.map(t => t.id));
    for (const row of world.grid) {
      for (const tileId of row) {
        expect(validIds.has(tileId)).toBe(true);
      }
    }
  });

  it('is deterministic — same seed same map', () => {
    const w1 = generateWorld(biome, 42);
    const w2 = generateWorld(biome, 42);
    expect(w1.grid).toEqual(w2.grid);
  });

  it('different seeds produce different maps', () => {
    const w1 = generateWorld(biome, 42);
    const w2 = generateWorld(biome, 99);
    expect(w1.grid).not.toEqual(w2.grid);
  });

  it('stores seed and biome reference', () => {
    const world = generateWorld(biome, 12345);
    expect(world.seed).toBe(12345);
    expect(world.biome).toBe(biome);
  });

  it('has diverse tile distribution (no single tile > 60%)', () => {
    const world = generateWorld(biome, 42);
    const counts = new Map<number, number>();
    for (const row of world.grid) {
      for (const tileId of row) {
        counts.set(tileId, (counts.get(tileId) ?? 0) + 1);
      }
    }
    const total = biome.mapWidth * biome.mapHeight;
    // At least 4 different tile types present
    expect(counts.size).toBeGreaterThanOrEqual(4);
    // No single type dominates
    for (const count of counts.values()) {
      expect(count / total).toBeLessThan(0.6);
    }
  });

  it('generates acid pools (low elevation)', () => {
    const world = generateWorld(biome, 42);
    const acidId = biome.tiles.find(t => t.name === 'acid-pool')?.id;
    const hasAcid = world.grid.some(row => row.includes(acidId!));
    expect(hasAcid).toBe(true);
  });

  it('generates crystal formations (high elevation)', () => {
    const world = generateWorld(biome, 42);
    const crystalId = biome.tiles.find(t => t.name === 'crystal')?.id;
    const hasCrystals = world.grid.some(row => row.includes(crystalId!));
    expect(hasCrystals).toBe(true);
  });

  it('generates mineral veins (overlay on ground)', () => {
    const world = generateWorld(biome, 42);
    const mineralId = biome.tiles.find(t => t.name === 'mineral-vein')?.id;
    const hasMinerals = world.grid.some(row => row.includes(mineralId!));
    expect(hasMinerals).toBe(true);
  });

  it('generates geysers (overlay near acid)', () => {
    const world = generateWorld(biome, 42);
    const geyserId = biome.tiles.find(t => t.name === 'geyser')?.id;
    const hasGeysers = world.grid.some(row => row.includes(geyserId!));
    expect(hasGeysers).toBe(true);
  });

  it('produces unique map every seed (sample 5 seeds)', () => {
    const grids = [1, 2, 3, 4, 5].map(s => generateWorld(biome, s).grid);
    for (let i = 0; i < grids.length; i++) {
      for (let j = i + 1; j < grids.length; j++) {
        expect(grids[i]).not.toEqual(grids[j]);
      }
    }
  });
});