/**
 * Integration tests for getPhaseReviewDiff caching behaviour.
 *
 * Verifies that git diff is only invoked once per HEAD hash and that
 * cache invalidation after a task merge triggers a re-run.
 */

import { describe, it, expect, vi, beforeEach } from 'vitest';
import { router, publicProcedure, createCallerFactory } from '../trpc.js';
import { phaseProcedures } from './phase.js';
import type { TRPCContext } from '../context.js';
import type { BranchManager } from '../../git/branch-manager.js';
import { createTestDatabase } from '../../db/repositories/drizzle/test-helpers.js';
import {
  DrizzleInitiativeRepository,
  DrizzlePhaseRepository,
  DrizzleProjectRepository,
} from '../../db/repositories/drizzle/index.js';
import { phaseMetaCache, fileDiffCache } from '../../review/diff-cache.js';

// =============================================================================
// Mock ensureProjectClone — prevents actual git cloning
// =============================================================================

vi.mock('../../git/project-clones.js', () => ({
  ensureProjectClone: vi.fn().mockResolvedValue('/fake/clone/path'),
  getProjectCloneDir: vi.fn().mockReturnValue('repos/fake-project-id'),
}));

// =============================================================================
// Test router
// =============================================================================

const testRouter = router({
  ...phaseProcedures(publicProcedure),
});

const createCaller = createCallerFactory(testRouter);

// =============================================================================
// MockBranchManager
// =============================================================================

function makeMockBranchManager(): BranchManager {
  return {
    ensureBranch: vi.fn().mockResolvedValue(undefined),
    mergeBranch: vi.fn().mockResolvedValue({ success: true, conflictFiles: [] }),
    diffBranches: vi.fn().mockResolvedValue('diff --git a/file.ts'),
    diffBranchesStat: vi.fn().mockResolvedValue([]),
    diffFileSingle: vi.fn().mockResolvedValue('diff --git a/file.ts'),
    deleteBranch: vi.fn().mockResolvedValue(undefined),
    branchExists: vi.fn().mockResolvedValue(true),
    remoteBranchExists: vi.fn().mockResolvedValue(true),
    listCommits: vi.fn().mockResolvedValue([]),
    diffCommit: vi.fn().mockResolvedValue(''),
    getMergeBase: vi.fn().mockResolvedValue('mergebase123'),
    pushBranch: vi.fn().mockResolvedValue(undefined),
    checkMergeability: vi.fn().mockResolvedValue({ canMerge: true, conflicts: [] }),
    fetchRemote: vi.fn().mockResolvedValue(undefined),
    fastForwardBranch: vi.fn().mockResolvedValue(undefined),
    updateRef: vi.fn().mockResolvedValue(undefined),
    getHeadCommitHash: vi.fn().mockResolvedValue('abc123def456'),
  };
}

// =============================================================================
// Helpers
// =============================================================================

function createMockEventBus(): TRPCContext['eventBus'] {
  return {
    emit: vi.fn(),
    on: vi.fn(),
    off: vi.fn(),
    once: vi.fn(),
  };
}

interface SeedResult {
  phaseId: string;
  initiativeId: string;
  projectId: string;
}

async function seedDatabase(): Promise<{
  repos: {
    initiativeRepo: DrizzleInitiativeRepository;
    phaseRepo: DrizzlePhaseRepository;
    projectRepo: DrizzleProjectRepository;
  };
  data: SeedResult;
}> {
  const db = createTestDatabase();
  const initiativeRepo = new DrizzleInitiativeRepository(db);
  const phaseRepo = new DrizzlePhaseRepository(db);
  const projectRepo = new DrizzleProjectRepository(db);

  const initiative = await initiativeRepo.create({
    name: 'Test Initiative',
    status: 'active',
    branch: 'main',
  });

  const phase = await phaseRepo.create({
    initiativeId: initiative.id,
    name: 'Test Phase',
    status: 'pending_review',
  });

  const project = await projectRepo.create({
    name: 'Test Project',
    url: 'https://github.com/test/repo',
  });

  await projectRepo.addProjectToInitiative(initiative.id, project.id);

  return {
    repos: { initiativeRepo, phaseRepo, projectRepo },
    data: { phaseId: phase.id, initiativeId: initiative.id, projectId: project.id },
  };
}

async function seedDatabaseNoProjects(): Promise<{
  repos: {
    initiativeRepo: DrizzleInitiativeRepository;
    phaseRepo: DrizzlePhaseRepository;
    projectRepo: DrizzleProjectRepository;
  };
  data: { phaseId: string };
}> {
  const db = createTestDatabase();
  const initiativeRepo = new DrizzleInitiativeRepository(db);
  const phaseRepo = new DrizzlePhaseRepository(db);
  const projectRepo = new DrizzleProjectRepository(db);

  const initiative = await initiativeRepo.create({
    name: 'Test Initiative No Projects',
    status: 'active',
    branch: 'main',
  });

  const phase = await phaseRepo.create({
    initiativeId: initiative.id,
    name: 'Empty Phase',
    status: 'pending_review',
  });

  return {
    repos: { initiativeRepo, phaseRepo, projectRepo },
    data: { phaseId: phase.id },
  };
}

function makeCaller(
  branchManager: BranchManager,
  repos: {
    initiativeRepo: DrizzleInitiativeRepository;
    phaseRepo: DrizzlePhaseRepository;
    projectRepo: DrizzleProjectRepository;
  },
) {
  const ctx: TRPCContext = {
    eventBus: createMockEventBus(),
    serverStartedAt: null,
    processCount: 0,
    branchManager,
    initiativeRepository: repos.initiativeRepo,
    phaseRepository: repos.phaseRepo,
    projectRepository: repos.projectRepo,
    workspaceRoot: '/fake/workspace',
  };
  return createCaller(ctx);
}

// =============================================================================
// Tests
// =============================================================================

beforeEach(() => {
  // Clear caches between tests to ensure isolation
  phaseMetaCache.invalidateByPrefix('');
  fileDiffCache.invalidateByPrefix('');
});

describe('getPhaseReviewDiff caching', () => {
  it('second call for same phase/HEAD returns cached result without calling git again', async () => {
    const { repos, data } = await seedDatabase();
    const branchManager = makeMockBranchManager();
    const diffBranchesSpy = vi.spyOn(branchManager, 'diffBranchesStat');
    const caller = makeCaller(branchManager, repos);

    await caller.getPhaseReviewDiff({ phaseId: data.phaseId });
    await caller.getPhaseReviewDiff({ phaseId: data.phaseId });

    expect(diffBranchesSpy).toHaveBeenCalledTimes(1);
  });

  it('after cache invalidation, next call re-runs git diff', async () => {
    const { repos, data } = await seedDatabase();
    const branchManager = makeMockBranchManager();
    const diffBranchesSpy = vi.spyOn(branchManager, 'diffBranchesStat');
    const caller = makeCaller(branchManager, repos);

    await caller.getPhaseReviewDiff({ phaseId: data.phaseId });
    expect(diffBranchesSpy).toHaveBeenCalledTimes(1);

    // Simulate a task merge → cache invalidated
    phaseMetaCache.invalidateByPrefix(`${data.phaseId}:`);

    await caller.getPhaseReviewDiff({ phaseId: data.phaseId });
    expect(diffBranchesSpy).toHaveBeenCalledTimes(2);
  });

  it('different HEAD hashes for same phase are treated as distinct cache entries', async () => {
    const { repos, data } = await seedDatabase();
    const branchManager = makeMockBranchManager();
    const diffBranchesSpy = vi.spyOn(branchManager, 'diffBranchesStat');
    const caller = makeCaller(branchManager, repos);

    // First call with headHash = 'abc123'
    vi.spyOn(branchManager, 'getHeadCommitHash').mockResolvedValueOnce('abc123');
    await caller.getPhaseReviewDiff({ phaseId: data.phaseId });

    // Second call with headHash = 'def456' (simulates a new commit)
    vi.spyOn(branchManager, 'getHeadCommitHash').mockResolvedValueOnce('def456');
    await caller.getPhaseReviewDiff({ phaseId: data.phaseId });

    expect(diffBranchesSpy).toHaveBeenCalledTimes(2);
  });

  it('throws NOT_FOUND for nonexistent phaseId', async () => {
    const { repos } = await seedDatabase();
    const caller = makeCaller(makeMockBranchManager(), repos);

    await expect(caller.getPhaseReviewDiff({ phaseId: 'nonexistent' }))
      .rejects.toMatchObject({ code: 'NOT_FOUND' });
  });

  it('phase with no projects returns empty result without calling git', async () => {
    const { repos, data } = await seedDatabaseNoProjects();
    const branchManager = makeMockBranchManager();
    const diffBranchesSpy = vi.spyOn(branchManager, 'diffBranchesStat');
    const caller = makeCaller(branchManager, repos);

    const result = await caller.getPhaseReviewDiff({ phaseId: data.phaseId });
    expect(diffBranchesSpy).not.toHaveBeenCalled();
    expect(result).toHaveProperty('phaseName');
  });
});