import { describe, it, expect } from 'vitest';
import {
    addEffect,
    addEntityEffect,
    addItemEffect,
    onEntityEffectUpkeep,
    onEntityPostureDamage,
    onPlayerItemEffectUpkeep,
    onItemPlay,
    onItemDiscard,
    getAliveEnemies,
    getCombatEntity,
} from '@/samples/slay-the-spire-like/system/combat/effects';
import type { CombatEntity, CombatState, EffectTable, PlayerEntity, EnemyEntity } from '@/samples/slay-the-spire-like/system/combat/types';
import type { EffectData } from '@/samples/slay-the-spire-like/system/types';

function createEffect(id: string, lifecycle: EffectData['lifecycle']): EffectData {
    return { id, name: id, description: '', lifecycle };
}

function createCombatEntity(hp = 10, maxHp = 10): CombatEntity {
    return {
        effects: {},
        hp,
        maxHp,
        isAlive: hp > 0,
    };
}

function createPlayerEntity(hp = 30, maxHp = 30): PlayerEntity {
    return {
        ...createCombatEntity(hp, maxHp),
        energy: 3,
        maxEnergy: 3,
        deck: { cards: {}, regions: { drawPile: { id: 'drawPile', axes: [], childIds: [], partMap: {} }, hand: { id: 'hand', axes: [], childIds: [], partMap: {} }, discardPile: { id: 'discardPile', axes: [], childIds: [], partMap: {} }, exhaustPile: { id: 'exhaustPile', axes: [], childIds: [], partMap: {} } } },
        itemEffects: {},
    };
}

function createEnemyEntity(id: string, hp = 10, maxHp = 10): EnemyEntity {
    return {
        ...createCombatEntity(hp, maxHp),
        id,
        enemy: { id, name: id, description: '' },
        intents: {},
        currentIntentId: '',
    };
}

function createCombatState(playerHp = 30, enemies: EnemyEntity[] = []): CombatState {
    return {
        player: createPlayerEntity(playerHp),
        enemies,
        inventory: { width: 6, height: 4, items: new Map(), occupiedCells: new Set() },
        phase: 'playerTurn',
        turnNumber: 1,
        result: null,
        loot: [],
    };
}

describe('combat/effects', () => {
    describe('addEffect', () => {
        it('should add a new effect to an empty table', () => {
            const table: EffectTable = {};
            const effect = createEffect('strength', 'temporary');

            addEffect(table, effect, 3);

            expect(table['strength']).toBeDefined();
            expect(table['strength'].data).toBe(effect);
            expect(table['strength'].stacks).toBe(3);
        });

        it('should stack with existing effect of same id', () => {
            const table: EffectTable = {};
            const effect = createEffect('strength', 'lingering');

            addEffect(table, effect, 2);
            addEffect(table, effect, 3);

            expect(table['strength'].stacks).toBe(5);
        });

        it('should remove effect when stacks reach 0', () => {
            const table: EffectTable = {};
            const effect = createEffect('strength', 'temporary');

            addEffect(table, effect, 3);
            addEffect(table, effect, -3);

            expect(table['strength']).toBeUndefined();
        });

        it('should not add effect when stacks is 0', () => {
            const table: EffectTable = {};
            const effect = createEffect('strength', 'temporary');

            addEffect(table, effect, 0);

            expect(table['strength']).toBeUndefined();
        });

        it('should handle negative stacks', () => {
            const table: EffectTable = {};
            const effect = createEffect('weak', 'temporary');

            addEffect(table, effect, -2);

            expect(table['weak'].stacks).toBe(-2);
        });
    });

    describe('addEntityEffect', () => {
        it('should add effect to entity.effects', () => {
            const entity = createCombatEntity();
            const effect = createEffect('vulnerable', 'lingering');

            addEntityEffect(entity, effect, 2);

            expect(entity.effects['vulnerable'].stacks).toBe(2);
        });
    });

    describe('addItemEffect', () => {
        it('should add effect to player.itemEffects[itemKey]', () => {
            const player = createPlayerEntity();
            const effect = createEffect('adjacent-buff', 'itemTemporary');

            addItemEffect(player, 'sword-1', effect, 3);

            expect(player.itemEffects['sword-1']['adjacent-buff'].stacks).toBe(3);
        });

        it('should initialize itemEffects entry if not present', () => {
            const player = createPlayerEntity();
            const effect = createEffect('adjacent-buff', 'itemTemporary');

            addItemEffect(player, 'new-item', effect, 1);

            expect(player.itemEffects['new-item']).toBeDefined();
        });

        it('should stack with existing item effect', () => {
            const player = createPlayerEntity();
            const effect = createEffect('adjacent-buff', 'itemTemporary');

            addItemEffect(player, 'sword-1', effect, 2);
            addItemEffect(player, 'sword-1', effect, 3);

            expect(player.itemEffects['sword-1']['adjacent-buff'].stacks).toBe(5);
        });
    });

    describe('onEntityEffectUpkeep', () => {
        it('should remove temporary effects', () => {
            const entity = createCombatEntity();
            const tempEffect = createEffect('temp-shield', 'temporary');

            addEntityEffect(entity, tempEffect, 5);
            onEntityEffectUpkeep(entity);

            expect(entity.effects['temp-shield']).toBeUndefined();
        });

        it('should decrement lingering effects by 1', () => {
            const entity = createCombatEntity();
            const lingeringEffect = createEffect('poison', 'lingering');

            addEntityEffect(entity, lingeringEffect, 3);
            onEntityEffectUpkeep(entity);

            expect(entity.effects['poison'].stacks).toBe(2);
        });

        it('should remove lingering effects when stacks reach 0', () => {
            const entity = createCombatEntity();
            const lingeringEffect = createEffect('poison', 'lingering');

            addEntityEffect(entity, lingeringEffect, 1);
            onEntityEffectUpkeep(entity);

            expect(entity.effects['poison']).toBeUndefined();
        });

        it('should not affect permanent effects', () => {
            const entity = createCombatEntity();
            const permEffect = createEffect('max-hp-up', 'permanent');

            addEntityEffect(entity, permEffect, 5);
            onEntityEffectUpkeep(entity);

            expect(entity.effects['max-hp-up'].stacks).toBe(5);
        });

        it('should not affect instant effects', () => {
            const entity = createCombatEntity();
            const instantEffect = createEffect('instant-damage', 'instant');

            addEntityEffect(entity, instantEffect, 10);
            onEntityEffectUpkeep(entity);

            expect(entity.effects['instant-damage'].stacks).toBe(10);
        });

        it('should increment lingering effects with negative stacks', () => {
            const entity = createCombatEntity();
            const lingeringEffect = createEffect('regen', 'lingering');

            addEntityEffect(entity, lingeringEffect, -3);
            onEntityEffectUpkeep(entity);

            expect(entity.effects['regen'].stacks).toBe(-2);
        });
    });

    describe('onEntityPostureDamage', () => {
        it('should reduce posture effects by damage amount', () => {
            const entity = createCombatEntity();
            const postureEffect = createEffect('block', 'posture');

            addEntityEffect(entity, postureEffect, 10);
            onEntityPostureDamage(entity, 4);

            expect(entity.effects['block'].stacks).toBe(6);
        });

        it('should not reduce posture effects below 0', () => {
            const entity = createCombatEntity();
            const postureEffect = createEffect('block', 'posture');

            addEntityEffect(entity, postureEffect, 3);
            onEntityPostureDamage(entity, 10);

            expect(entity.effects['block']).toBeUndefined();
        });

        it('should not affect non-posture effects', () => {
            const entity = createCombatEntity();
            const postureEffect = createEffect('block', 'posture');
            const permEffect = createEffect('strength', 'permanent');

            addEntityEffect(entity, postureEffect, 5);
            addEntityEffect(entity, permEffect, 3);
            onEntityPostureDamage(entity, 2);

            expect(entity.effects['block'].stacks).toBe(3);
            expect(entity.effects['strength'].stacks).toBe(3);
        });

        it('should handle zero damage', () => {
            const entity = createCombatEntity();
            const postureEffect = createEffect('block', 'posture');

            addEntityEffect(entity, postureEffect, 5);
            onEntityPostureDamage(entity, 0);

            expect(entity.effects['block'].stacks).toBe(5);
        });
    });

    describe('onPlayerItemEffectUpkeep', () => {
        it('should remove itemTemporary effects', () => {
            const player = createPlayerEntity();
            const effect = createEffect('adjacent-buff', 'itemTemporary');

            addItemEffect(player, 'sword-1', effect, 5);
            onPlayerItemEffectUpkeep(player);

            expect(player.itemEffects['sword-1']['adjacent-buff']).toBeUndefined();
        });

        it('should not affect itemPermanent effects', () => {
            const player = createPlayerEntity();
            const effect = createEffect('adjacent-buff', 'itemPermanent');

            addItemEffect(player, 'sword-1', effect, 5);
            onPlayerItemEffectUpkeep(player);

            expect(player.itemEffects['sword-1']['adjacent-buff'].stacks).toBe(5);
        });

        it('should not affect itemUntilPlay effects', () => {
            const player = createPlayerEntity();
            const effect = createEffect('charged', 'itemUntilPlay');

            addItemEffect(player, 'sword-1', effect, 3);
            onPlayerItemEffectUpkeep(player);

            expect(player.itemEffects['sword-1']['charged'].stacks).toBe(3);
        });
    });

    describe('onItemPlay', () => {
        it('should remove itemUntilPlay effects', () => {
            const player = createPlayerEntity();
            const effect = createEffect('charged', 'itemUntilPlay');

            addItemEffect(player, 'sword-1', effect, 3);
            onItemPlay(player, 'sword-1');

            expect(player.itemEffects['sword-1']['charged']).toBeUndefined();
        });

        it('should not affect other lifecycle effects', () => {
            const player = createPlayerEntity();
            const permEffect = createEffect('passive', 'itemPermanent');
            const playEffect = createEffect('charged', 'itemUntilPlay');

            addItemEffect(player, 'sword-1', permEffect, 5);
            addItemEffect(player, 'sword-1', playEffect, 3);
            onItemPlay(player, 'sword-1');

            expect(player.itemEffects['sword-1']['passive'].stacks).toBe(5);
            expect(player.itemEffects['sword-1']['charged']).toBeUndefined();
        });

        it('should do nothing for item with no effects', () => {
            const player = createPlayerEntity();

            expect(() => onItemPlay(player, 'nonexistent')).not.toThrow();
        });
    });

    describe('onItemDiscard', () => {
        it('should remove itemUntilDiscard effects', () => {
            const player = createPlayerEntity();
            const effect = createEffect('discard-buff', 'itemUntilDiscard');

            addItemEffect(player, 'sword-1', effect, 3);
            onItemDiscard(player, 'sword-1');

            expect(player.itemEffects['sword-1']['discard-buff']).toBeUndefined();
        });

        it('should not affect other lifecycle effects', () => {
            const player = createPlayerEntity();
            const permEffect = createEffect('passive', 'itemPermanent');
            const discardEffect = createEffect('discard-buff', 'itemUntilDiscard');

            addItemEffect(player, 'sword-1', permEffect, 5);
            addItemEffect(player, 'sword-1', discardEffect, 3);
            onItemDiscard(player, 'sword-1');

            expect(player.itemEffects['sword-1']['passive'].stacks).toBe(5);
            expect(player.itemEffects['sword-1']['discard-buff']).toBeUndefined();
        });

        it('should do nothing for item with no effects', () => {
            const player = createPlayerEntity();

            expect(() => onItemDiscard(player, 'nonexistent')).not.toThrow();
        });
    });

    describe('getAliveEnemies', () => {
        it('should yield only alive enemies', () => {
            const state = createCombatState(30, [
                createEnemyEntity('slime-1', 10, 10),
                createEnemyEntity('slime-2', 0, 10),
                createEnemyEntity('slime-3', 5, 10),
            ]);

            const alive = [...getAliveEnemies(state)];

            expect(alive.length).toBe(2);
            expect(alive[0].id).toBe('slime-1');
            expect(alive[1].id).toBe('slime-3');
        });

        it('should return empty for no enemies', () => {
            const state = createCombatState(30, []);

            const alive = [...getAliveEnemies(state)];

            expect(alive.length).toBe(0);
        });

        it('should return empty when all enemies are dead', () => {
            const state = createCombatState(30, [
                createEnemyEntity('slime-1', 0, 10),
                createEnemyEntity('slime-2', 0, 10),
            ]);

            const alive = [...getAliveEnemies(state)];

            expect(alive.length).toBe(0);
        });
    });

    describe('getCombatEntity', () => {
        it('should return player for "player" key', () => {
            const state = createCombatState(30);

            const entity = getCombatEntity(state, 'player');

            expect(entity).toBe(state.player);
        });

        it('should return enemy by id', () => {
            const enemy = createEnemyEntity('boss-1', 50, 50);
            const state = createCombatState(30, [enemy]);

            const entity = getCombatEntity(state, 'boss-1');

            expect(entity).toBe(enemy);
        });

        it('should return undefined for non-existent enemy', () => {
            const state = createCombatState(30, [createEnemyEntity('slime-1')]);

            const entity = getCombatEntity(state, 'nonexistent');

            expect(entity).toBeUndefined();
        });
    });
});