import { describe, expect, test, beforeEach, afterEach } from 'bun:test'
import { mkdirSync, writeFileSync, rmSync, existsSync } from 'fs'
import { join } from 'path'
import { constructPrompt, type PromptPhase } from './prompt'
import type { HoneConfig } from './config'

const TEST_WORKSPACE = join(process.cwd(), '.test-prompt-workspace')
const TEST_PLANS_DIR = join(TEST_WORKSPACE, '.plans')

beforeEach(() => {
  // Create isolated test workspace
  if (existsSync(TEST_WORKSPACE)) {
    rmSync(TEST_WORKSPACE, { recursive: true, force: true })
  }
  mkdirSync(TEST_PLANS_DIR, { recursive: true })

  // Change to test workspace
  process.chdir(TEST_WORKSPACE)
})

afterEach(() => {
  // Clean up and return to original directory
  const originalDir = join(TEST_WORKSPACE, '..')
  process.chdir(originalDir)
  if (existsSync(TEST_WORKSPACE)) {
    rmSync(TEST_WORKSPACE, { recursive: true, force: true })
  }
})

const mockConfig: HoneConfig = {
  version: 2,
  agent: 'claude',
  claude: { model: 'claude-sonnet-4-20250514', models: {} },
  opencode: { model: 'claude-sonnet-4-20250514', models: {} },
  lintCommand: 'bun run lint',
}

describe('constructPrompt', () => {
  test('includes phase header', () => {
    // Create minimal task file
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('# HONE: IMPLEMENT PHASE')
  })

  test('includes AGENTS.md reference if exists', () => {
    writeFileSync(join(TEST_WORKSPACE, 'AGENTS.md'), '# Learning 1\nSome pattern')
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('# CONTEXT FILES')
    expect(prompt).toContain('@AGENTS.md')
  })

  test('includes task file reference', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    title: Test Task\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('# CONTEXT FILES')
    expect(prompt).toContain('@.plans/tasks-test.yml')
  })

  test('includes progress file reference if exists', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )
    writeFileSync(join(TEST_PLANS_DIR, 'progress-test.txt'), 'Previous iteration completed')

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('# CONTEXT FILES')
    expect(prompt).toContain('@.plans/progress-test.txt')
  })

  test('implement phase includes task selection instructions', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('# TASK SELECTION')
    expect(prompt).toContain('bun test')
  })

  test('implement phase includes lint command if configured', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('bun run lint')
  })

  test('review phase includes review checklist', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'review',
      featureName: 'test',
      config: mockConfig,
      taskId: 'task-001',
    })

    expect(prompt).toContain('# HONE: REVIEW PHASE')
    expect(prompt).toContain('# REVIEW CHECKLIST')
    expect(prompt).toContain('Correctness')
    expect(prompt).toContain('elegantly written')
    expect(prompt).toContain('task-001')
  })

  test('finalize phase includes review feedback', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const feedback = '**Issue**: Missing error handling\n**Suggestion**: Add try-catch'
    const prompt = constructPrompt({
      phase: 'finalize',
      featureName: 'test',
      config: mockConfig,
      taskId: 'task-001',
      reviewFeedback: feedback,
    })

    expect(prompt).toContain('# HONE: FINALIZE PHASE')
    expect(prompt).toContain('# REVIEW FEEDBACK')
    expect(prompt).toContain('Missing error handling')
  })

  test('finalize phase without review feedback shows default message', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'finalize',
      featureName: 'test',
      config: mockConfig,
      taskId: 'task-001',
    })

    expect(prompt).toContain('No review feedback provided')
  })

  test('handles missing AGENTS.md gracefully', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).not.toContain('@AGENTS.md')
    expect(prompt).toContain('# TASK SELECTION')
  })

  test('handles missing progress file gracefully', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).not.toContain('progress-test.txt')
    expect(prompt).toContain('# TASK SELECTION')
  })

  test('uses default feedback instructions', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('test: bun test')
  })

  test('implement phase includes failure handling instructions', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('If tests fail or there are errors you cannot fix')
    expect(prompt).toContain('DO NOT output TASK_COMPLETED')
    expect(prompt).toContain('task will remain pending')
    expect(prompt).toContain('Only output this marker if the task is fully complete')
  })

  test('implement phase contains in_progress status instruction', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain('in_progress')
  })

  test('review phase contains started task check, prioritization, and fallback instructions', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'review',
      featureName: 'test',
      config: mockConfig,
      taskId: 'task-001',
    })

    expect(prompt).toContain('in_progress')
    expect(prompt).toContain('prioritize')
    expect(prompt).toContain('default review behavior')
  })

  test('implement phase enforces task file isolation', () => {
    writeFileSync(
      join(TEST_PLANS_DIR, 'tasks-test.yml'),
      'tasks:\n  - id: task-001\n    status: pending\n'
    )

    const prompt = constructPrompt({
      phase: 'implement',
      featureName: 'test',
      config: mockConfig,
    })

    expect(prompt).toContain(
      'CRITICAL: You MUST only choose tasks from the task file referenced in CONTEXT FILES'
    )
    expect(prompt).toContain('Do NOT select tasks from any other task file')
  })
})