import { describe, expect, it } from 'vitest';
import { buildContent } from '../../content/schema';
import { createGameState, startAction } from '../game';
import {
  applyOfflineProgress,
  createSave,
  deserializeSave,
  fromExportString,
  SAVE_VERSION,
  serializeSave,
  toExportString,
} from '../save';

function testContent() {
  return buildContent({
    resources: [{ id: 'gold', name: 'Gold', startAmount: 0 }],
    actions: [
      {
        id: 'forage',
        name: 'Forage',
        durationMs: 3000,
        yields: [{ resourceId: 'gold', amount: 1 }],
      },
    ],
  });
}

function sampleState() {
  const content = testContent();
  const state = createGameState(content);
  state.resources.gold = 12;
  startAction(state, content, 'forage');
  state.actionElapsedMs = 500;
  return state;
}

describe('createSave()', () => {
  it('stamps the current version and timestamp around a snapshot of state', () => {
    const save = createSave(sampleState(), 1700);
    expect(save.version).toBe(SAVE_VERSION);
    expect(save.savedAt).toBe(1700);
    expect(save.state.resources.gold).toBe(12);
    expect(save.state.activeActionId).toBe('forage');
  });

  it('snapshots state so later mutation does not affect the save', () => {
    const state = sampleState();
    const save = createSave(state, 1700);
    state.resources.gold = 999;
    expect(save.state.resources.gold).toBe(12);
  });

  it('snapshots actionQueue in save payload', () => {
    const state = sampleState();
    state.actionQueue = ['forage', 'forage'];
    const save = createSave(state, 1700);
    expect(save.state.actionQueue).toEqual(['forage', 'forage']);
    state.actionQueue.push('forage');
    expect(save.state.actionQueue).toEqual(['forage', 'forage']);
  });
});

describe('serialize / deserialize round-trip', () => {
  it('survives JSON serialization unchanged', () => {
    const save = createSave(sampleState(), 1700);
    const restored = deserializeSave(serializeSave(save));
    expect(restored).toEqual(save);
  });

  it('survives the compressed export string unchanged', () => {
    const save = createSave(sampleState(), 1700);
    const restored = fromExportString(toExportString(save));
    expect(restored).toEqual(save);
  });
});

describe('invalid / tampered saves', () => {
  it('rejects a non-JSON export string cleanly', () => {
    expect(() => fromExportString('@@@not-a-valid-payload@@@')).toThrow();
  });

  it('rejects JSON that does not match the save schema', () => {
    expect(() => deserializeSave('{"version":1,"savedAt":1,"state":{}}')).toThrow();
  });

  it('rejects an unsupported save version', () => {
    const future = JSON.stringify({
      version: 999,
      savedAt: 1,
      state: { resources: {}, activeActionId: null, actionElapsedMs: 0 },
    });
    expect(() => deserializeSave(future)).toThrow(/version/i);
  });
});

describe('applyOfflineProgress()', () => {
  it('credits whole ticks of elapsed time to the active action', () => {
    const content = testContent();
    const state = createGameState(content);
    startAction(state, content, 'forage'); // 3000ms per gold
    const credited = applyOfflineProgress(state, content, 1000, 1000 + 9000); // 9s
    expect(credited).toBe(9000);
    expect(state.resources.gold).toBe(1); // one completion then idle
    expect(state.activeActionId).toBeNull();
  });

  it('credits nothing when the clock did not advance', () => {
    const content = testContent();
    const state = createGameState(content);
    startAction(state, content, 'forage');
    expect(applyOfflineProgress(state, content, 5000, 4000)).toBe(0);
    expect(state.resources.gold).toBe(0);
  });

  it('clamps credited time to the offline cap', () => {
    const content = testContent();
    const state = createGameState(content);
    startAction(state, content, 'forage');
    const credited = applyOfflineProgress(state, content, 0, 10_000_000, 6000);
    expect(credited).toBe(6000);
    expect(state.resources.gold).toBe(1); // one completion then idle
    expect(state.activeActionId).toBeNull();
  });
});