import { describe, it, expect, beforeEach } from 'vitest';
import { createWorld, addEntity, addComponent, query } from 'bitecs';
import type { World } from '../src/ecs/world';
import {
  Position,
  Health,
  Creature,
  AI,
  Metabolism,
  LifeCycle,
  Projectile,
  PlayerTag,
  SpriteRef,
  Velocity,
} from '../src/ecs/components';
import { SpeciesId, AIState, LifeStage } from '../src/creatures/types';
import type { SpeciesData, CreatureInfo } from '../src/creatures/types';
import { createCreatureEntity } from '../src/creatures/factory';
import {
  creatureProjectileSystem,
  getObservableCreatures,
  creatureAttackPlayerSystem,
} from '../src/creatures/interaction';
import type { ProjectileData } from '../src/player/projectile';
import speciesDataArray from '../src/data/creatures.json';

// ─── Helpers ─────────────────────────────────────────────────────

const allSpecies = speciesDataArray as SpeciesData[];

function getSpecies(id: string): SpeciesData {
  const s = allSpecies.find(s => s.id === id);
  if (!s) throw new Error(`Species not found: ${id}`);
  return s;
}

function buildSpeciesLookup(): Map<number, SpeciesData> {
  const map = new Map<number, SpeciesData>();
  for (const s of allSpecies) map.set(s.speciesId, s);
  return map;
}

function createProjectile(world: World, x: number, y: number, projData: Map<number, ProjectileData>): number {
  const eid = addEntity(world);
  addComponent(world, eid, Position);
  addComponent(world, eid, Projectile);
  addComponent(world, eid, SpriteRef);
  addComponent(world, eid, Velocity);
  Position.x[eid] = x;
  Position.y[eid] = y;
  Projectile.lifetime[eid] = 2000;
  SpriteRef.color[eid] = 0xffffff;
  SpriteRef.radius[eid] = 5;
  projData.set(eid, { itemId: 'Na' });
  return eid;
}

function createPlayer(world: World, x: number, y: number): number {
  const eid = addEntity(world);
  addComponent(world, eid, Position);
  addComponent(world, eid, PlayerTag);
  addComponent(world, eid, Health);
  Position.x[eid] = x;
  Position.y[eid] = y;
  Health.current[eid] = 100;
  Health.max[eid] = 100;
  return eid;
}

// ─── Projectile-Creature Collision ───────────────────────────────

describe('Projectile-Creature Collision', () => {
  let world: World;
  const speciesLookup = buildSpeciesLookup();

  beforeEach(() => {
    world = createWorld();
  });

  it('projectile hits creature within range', () => {
    const species = getSpecies('crystallid');
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    const hpBefore = Health.current[creature];

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 105, 100, projData); // 5px away, within 20px hit radius

    const hits = creatureProjectileSystem(world, projData, speciesLookup);

    expect(hits).toHaveLength(1);
    expect(hits[0].creatureEid).toBe(creature);
    expect(hits[0].killed).toBe(false);
    expect(Health.current[creature]).toBeLessThan(hpBefore);
  });

  it('projectile is removed after hitting creature', () => {
    const species = getSpecies('crystallid');
    createCreatureEntity(world, species, 100, 100, LifeStage.Mature);

    const projData = new Map<number, ProjectileData>();
    const projEid = createProjectile(world, 105, 100, projData);

    creatureProjectileSystem(world, projData, speciesLookup);

    // Projectile should be removed
    expect(projData.has(projEid)).toBe(false);
    expect([...query(world, [Projectile])]).not.toContain(projEid);
  });

  it('armor reduces damage (Crystallid has 0.3 armor)', () => {
    const species = getSpecies('crystallid'); // armor = 0.3
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 105, 100, projData);

    const hits = creatureProjectileSystem(world, projData, speciesLookup);

    // Base damage 15, armor 0.3 → 15 * 0.7 = 10.5 → rounded to 11
    expect(hits[0].damage).toBe(11);
  });

  it('Reagent takes full damage (0 armor)', () => {
    const species = getSpecies('reagent'); // armor = 0
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 105, 100, projData);

    const hits = creatureProjectileSystem(world, projData, speciesLookup);

    expect(hits[0].damage).toBe(15);
  });

  it('projectile misses creature outside range', () => {
    const species = getSpecies('crystallid');
    createCreatureEntity(world, species, 100, 100, LifeStage.Mature);

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 200, 200, projData); // far away

    const hits = creatureProjectileSystem(world, projData, speciesLookup);

    expect(hits).toHaveLength(0);
  });

  it('passive creature flees after being hit', () => {
    const species = getSpecies('crystallid'); // aggressionRadius = 0 → passive
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 105, 100, projData);

    creatureProjectileSystem(world, projData, speciesLookup);

    expect(AI.state[creature]).toBe(AIState.Flee);
  });

  it('aggressive creature attacks player after being hit', () => {
    const species = getSpecies('acidophile'); // aggressionRadius = 100 → aggressive
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    const player = createPlayer(world, 150, 100);

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 105, 100, projData);

    creatureProjectileSystem(world, projData, speciesLookup);

    expect(AI.state[creature]).toBe(AIState.Attack);
    expect(AI.targetEid[creature]).toBe(player);
  });

  it('killing a creature reports killed=true', () => {
    const species = getSpecies('reagent'); // 60 hp
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    Health.current[creature] = 10; // nearly dead

    const projData = new Map<number, ProjectileData>();
    createProjectile(world, 105, 100, projData);

    const hits = creatureProjectileSystem(world, projData, speciesLookup);

    expect(hits[0].killed).toBe(true);
  });
});

// ─── Creature Observation ────────────────────────────────────────

describe('Creature Observation', () => {
  let world: World;

  beforeEach(() => {
    world = createWorld();
  });

  it('detects creature near player', () => {
    const species = getSpecies('crystallid');
    createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    createPlayer(world, 120, 100); // 20px away, within 60px observe range

    const observations = getObservableCreatures(world);

    expect(observations).toHaveLength(1);
    expect(observations[0].speciesId).toBe(SpeciesId.Crystallid);
    expect(observations[0].stage).toBe(LifeStage.Mature);
  });

  it('does not detect distant creature', () => {
    const species = getSpecies('crystallid');
    createCreatureEntity(world, species, 500, 500, LifeStage.Mature);
    createPlayer(world, 100, 100);

    const observations = getObservableCreatures(world);

    expect(observations).toHaveLength(0);
  });

  it('returns health and energy percentages', () => {
    const species = getSpecies('crystallid');
    const eid = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    Health.current[eid] = 60; // 50% of 120
    Metabolism.energy[eid] = 50; // 50% of 100
    createPlayer(world, 110, 100);

    const observations = getObservableCreatures(world);

    expect(observations[0].healthPercent).toBe(50);
    expect(observations[0].energyPercent).toBe(50);
  });

  it('returns empty array when no player', () => {
    const species = getSpecies('crystallid');
    createCreatureEntity(world, species, 100, 100, LifeStage.Mature);

    const observations = getObservableCreatures(world);

    expect(observations).toHaveLength(0);
  });
});

// ─── Creature Attacks Player ─────────────────────────────────────

describe('Creature Attacks Player', () => {
  let world: World;
  const speciesLookup = buildSpeciesLookup();

  beforeEach(() => {
    world = createWorld();
  });

  it('attacking creature damages player in range', () => {
    const species = getSpecies('reagent'); // attackRange = 18, damage = 20
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    const player = createPlayer(world, 110, 100); // 10px away

    AI.state[creature] = AIState.Attack;
    AI.targetEid[creature] = player;
    AI.attackCooldown[creature] = 0;

    const damage = creatureAttackPlayerSystem(world, speciesLookup);

    expect(damage).toBe(20);
    expect(Health.current[player]).toBe(80);
  });

  it('no damage if creature is out of range', () => {
    const species = getSpecies('reagent');
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    const player = createPlayer(world, 200, 100); // 100px, beyond attackRange 18

    AI.state[creature] = AIState.Attack;
    AI.targetEid[creature] = player;
    AI.attackCooldown[creature] = 0;

    const damage = creatureAttackPlayerSystem(world, speciesLookup);

    expect(damage).toBe(0);
  });

  it('attack cooldown prevents rapid attacks', () => {
    const species = getSpecies('reagent');
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    const player = createPlayer(world, 110, 100);

    AI.state[creature] = AIState.Attack;
    AI.targetEid[creature] = player;
    AI.attackCooldown[creature] = 500; // on cooldown

    const damage = creatureAttackPlayerSystem(world, speciesLookup);

    expect(damage).toBe(0);
  });

  it('non-attacking creature does not damage player', () => {
    const species = getSpecies('crystallid');
    const creature = createCreatureEntity(world, species, 100, 100, LifeStage.Mature);
    const player = createPlayer(world, 110, 100);

    AI.state[creature] = AIState.Wander; // not attacking
    AI.attackCooldown[creature] = 0;

    const damage = creatureAttackPlayerSystem(world, speciesLookup);

    expect(damage).toBe(0);
  });
});