/**
 * DoctorService - Diagnostic and repair service
 * DD §16.1. Self-bootstrap before capability checks.
 * INV-4: dependency installs originate here.
 *
 * @module packages/runtime/src/doctor/DoctorService
 */

import { existsSync, accessSync, constants, mkdirSync } from 'fs'
import { join } from 'path'
import { execFileSync } from 'child_process'

export interface DoctorCheck {
  name: string
  category: 'self_bootstrap' | 'capability' | 'project' | 'runtime' | 'toolchain' | 'display' | 'network' | 'provider'
  passed: boolean
  message: string
  fixable: boolean
  fix?: string
}

export interface DoctorReport {
  checks: DoctorCheck[]
  all_passed: boolean
  bootstrap_passed: boolean
  fixable_count: number
}

export class DoctorService {
  private project_root: string
  private capability_registry?: any

  constructor(project_root: string, capability_registry?: any) {
    this.project_root = project_root
    this.capability_registry = capability_registry
  }

  /**
   * Run all diagnostic checks.
   */
  async run_diagnostics(scope: 'all' | 'self_bootstrap' | 'capability' = 'all'): Promise<DoctorReport> {
    const checks: DoctorCheck[] = []

    // Self-bootstrap checks (always run first)
    checks.push(this.check_bun())
    checks.push(this.check_sqlite())
    checks.push(this.check_shell())
    checks.push(this.check_air_writability())

    const bootstrap_passed = checks.every(c => c.passed)
    if (!bootstrap_passed) {
      return { checks, all_passed: false, bootstrap_passed, fixable_count: checks.filter(c => c.fixable).length }
    }

    if (scope === 'self_bootstrap') {
      return { checks, all_passed: bootstrap_passed, bootstrap_passed, fixable_count: 0 }
    }

    // Capability checks
    checks.push(this.check_git())
    checks.push(this.check_node())
    checks.push(this.check_project_structure())

    // INV-4: Capability registry health — verify capability dependencies
    if (this.capability_registry) {
      checks.push(this.check_capability_deps())
    }

    // FR-018/§6.12: toolchain / display / network / provider checks
    if (scope === 'all') {
      checks.push(...this.check_cpp_toolchain())
      checks.push(this.check_display())
      checks.push(await this.check_network())
      checks.push(...await this.check_provider())
    }

    const all_passed = checks.every(c => c.passed)
    return { checks, all_passed, bootstrap_passed: true, fixable_count: checks.filter(c => c.fixable).length }
  }

  /**
   * Attempt to fix an issue.
   * INV-4: dependency installs originate here.
   */
  async fix(check_name: string): Promise<{ ok: boolean; message: string }> {
    // Implement self-repair logic per DD §16.1
    switch (check_name) {
      case 'bun': {
        return { ok: false, message: 'Bun installation requires manual setup. Run: curl -fsSL https://bun.sh/install | bash' }
      }
      case 'git': {
        return { ok: false, message: 'Git installation requires manual setup. Run: apt install git (Debian/Ubuntu)' }
      }
      case 'node': {
        return { ok: false, message: 'Node.js installation requires manual setup. Run: https://nodejs.org' }
      }
      case 'air_writability': {
        try {
          const air_dir = join(this.project_root, '.air')
          if (!existsSync(air_dir)) {
            mkdirSync(air_dir, { recursive: true })
          }
          mkdirSync(join(air_dir, 'shared'), { recursive: true })
          mkdirSync(join(air_dir, 'local'), { recursive: true })
          mkdirSync(join(air_dir, 'sessions'), { recursive: true })
          mkdirSync(join(air_dir, 'logs'), { recursive: true })
          return { ok: true, message: 'Created .air directory structure' }
        } catch (e) {
          return { ok: false, message: `Failed to create .air directory: ${e}` }
        }
      }
      case 'project_structure': {
        return { ok: false, message: 'Run air init to create project structure' }
      }
      case 'display': {
        try {
          execFileSync('sudo', ['apt', 'install', '-y', 'imagemagick'], { stdio: 'pipe', timeout: 60000 })
          return { ok: true, message: 'ImageMagick installed' }
        } catch (e: any) {
          return { ok: false, message: `ImageMagick install failed: ${e.message}` }
        }
      }
      default:
        // Toolchain fix: try apt install
        if (check_name.startsWith('toolchain.')) {
          const pkg = check_name.replace('toolchain.', '')
          const pkgMap: Record<string, string> = { cmake: 'cmake', ninja: 'ninja-build', cppcheck: 'cppcheck', clangd: 'clangd', 'g++': 'g++' }
          const aptPkg = pkgMap[pkg] || pkg
          try {
            execFileSync('sudo', ['apt', 'install', '-y', aptPkg], { stdio: 'pipe', timeout: 120000 })
            return { ok: true, message: `${pkg} installed via apt` }
          } catch (e: any) {
            return { ok: false, message: `Failed to install ${pkg}: ${e.message}` }
          }
        }
        return { ok: false, message: `Fix for ${check_name} not implemented` }
    }
  }

  private check_bun(): DoctorCheck {
    // Search bun in common paths, not just PATH
    const candidates = [
      'bun',  // PATH
      `${process.env.HOME || '/root'}/.bun/bin/bun`,
      '/usr/local/bin/bun',
      '/usr/bin/bun',
    ]
    for (const bun of candidates) {
      try {
        const version = execFileSync(bun, ['--version'], { stdio: 'pipe', timeout: 5000 }).toString().trim()
        return { name: 'bun', category: 'self_bootstrap', passed: true, message: `Bun ${version} found`, fixable: false }
      } catch { /* try next */ }
    }
    return { name: 'bun', category: 'self_bootstrap', passed: false, message: 'Bun not found', fixable: true, fix: 'Install Bun: curl -fsSL https://bun.sh/install | bash' }
  }

  private check_sqlite(): DoctorCheck {
    return { name: 'sqlite', category: 'self_bootstrap', passed: true, message: 'SQLite via Bun built-in', fixable: false }
  }

  private check_shell(): DoctorCheck {
    return { name: 'shell', category: 'self_bootstrap', passed: true, message: 'Shell available', fixable: false }
  }

  private check_air_writability(): DoctorCheck {
    const air_dir = join(this.project_root, '.air')
    try {
      if (!existsSync(air_dir)) {
        return { name: 'air_writability', category: 'self_bootstrap', passed: false, message: '.air directory does not exist', fixable: true, fix: 'Run project.initialize()' }
      }
      accessSync(air_dir, constants.W_OK)
      return { name: 'air_writability', category: 'self_bootstrap', passed: true, message: '.air directory is writable', fixable: false }
    } catch {
      return { name: 'air_writability', category: 'self_bootstrap', passed: false, message: '.air directory is not writable', fixable: true }
    }
  }

  private check_git(): DoctorCheck {
    try {
      execFileSync('git', ['--version'], { stdio: 'pipe', timeout: 5000 })
      return { name: 'git', category: 'capability', passed: true, message: 'Git available', fixable: false }
    } catch {
      return { name: 'git', category: 'capability', passed: false, message: 'Git not found', fixable: true, fix: 'Install Git: apt install git' }
    }
  }

  private check_node(): DoctorCheck {
    try {
      const version = execFileSync('node', ['--version'], { stdio: 'pipe', timeout: 5000 }).toString().trim()
      return { name: 'node', category: 'capability', passed: true, message: `Node.js ${version} available`, fixable: false }
    } catch {
      return { name: 'node', category: 'capability', passed: false, message: 'Node.js not found', fixable: true, fix: 'Install Node.js: https://nodejs.org' }
    }
  }

  private check_project_structure(): DoctorCheck {
    const required = ['package.json', 'tsconfig.json']
    const missing: string[] = []
    for (const file of required) {
      if (!existsSync(join(this.project_root, file))) {
        missing.push(file)
      }
    }
    if (missing.length > 0) {
      return { name: 'project_structure', category: 'project', passed: false, message: `Missing: ${missing.join(', ')}`, fixable: true, fix: 'Run air init to create project structure' }
    }
    return { name: 'project_structure', category: 'project', passed: true, message: 'Project structure valid', fixable: false }
  }

  /**
   * INV-4: Check capability registry health — verify capability dependencies
   * are installed and accessible. Bridges CapabilityRegistry → DoctorService.
   */
  private check_capability_deps(): DoctorCheck {
    try {
      const capabilities = this.capability_registry?.list?.() || []
      if (capabilities.length === 0) {
        return { name: 'capability_deps', category: 'capability', passed: true, message: 'No capabilities registered — nothing to check', fixable: false }
      }

      const missing_deps: string[] = []
      for (const cap of capabilities) {
        const entry = this.capability_registry?.get?.(cap.id) || cap
        const deps = entry?.manifest?.dependencies || []
        for (const dep of deps) {
          try {
            const { execFileSync } = require('child_process')
            execFileSync('which', [dep], { stdio: 'pipe', timeout: 3000 })
          } catch {
            missing_deps.push(`${cap.name || cap.id}:${dep}`)
          }
        }
      }

      if (missing_deps.length > 0) {
        return {
          name: 'capability_deps',
          category: 'capability',
          passed: false,
          message: `Missing capability dependencies: ${missing_deps.join(', ')}`,
          fixable: true,
          fix: 'Install missing tools: apt install ' + missing_deps.map(d => d.split(':')[1]).join(' ')
        }
      }
      return { name: 'capability_deps', category: 'capability', passed: true, message: `All ${capabilities.length} capabilities healthy`, fixable: false }
    } catch (e: any) {
      return { name: 'capability_deps', category: 'capability', passed: false, message: `Capability check failed: ${e.message}`, fixable: true }
    }
  }

  // ===== FR-018/§6.12: 5 new categories =====

  private check_cpp_toolchain(): DoctorCheck[] {
    const tools = ['cmake', 'ninja', 'cppcheck', 'clangd', 'g++']
    const reports: DoctorCheck[] = []
    for (const t of tools) {
      try {
        const v = execFileSync('which', [t], { stdio: 'pipe', timeout: 3000 }).toString().trim()
        reports.push({ name: `toolchain.${t}`, category: 'toolchain', passed: true, message: `${t} found at ${v}`, fixable: false })
      } catch {
        reports.push({ name: `toolchain.${t}`, category: 'toolchain', passed: false, message: `${t} not found`, fixable: true, fix: `apt install ${t === 'cmake' ? 'cmake' : t === 'ninja' ? 'ninja-build' : t}` })
      }
    }
    return reports
  }

  private check_display(): DoctorCheck {
    const display = process.env.DISPLAY
    const wayland = process.env.WAYLAND_DISPLAY
    if (!display && !wayland) {
      return { name: 'display', category: 'display', passed: false, message: 'No DISPLAY/WAYLAND_DISPLAY (gui.screenshot will fail)', fixable: false }
    }
    try {
      execFileSync('which', ['import'], { stdio: 'pipe' })
      return { name: 'display', category: 'display', passed: true, message: `Display ${display || wayland} + ImageMagick available`, fixable: false }
    } catch {
      return { name: 'display', category: 'display', passed: false, message: 'ImageMagick not installed', fixable: true, fix: 'apt install imagemagick' }
    }
  }

  private async check_network(): Promise<DoctorCheck> {
    try {
      const r = await fetch('https://1.1.1.1', { method: 'HEAD', signal: AbortSignal.timeout(3000) })
      return { name: 'network.internet', category: 'network', passed: r.ok || r.status > 0, message: `HTTP ${r.status}`, fixable: false }
    } catch (e: any) {
      return { name: 'network.internet', category: 'network', passed: false, message: e.message, fixable: false }
    }
  }

  private async check_provider(): Promise<DoctorCheck[]> {
    const reports: DoctorCheck[] = []
    const apiKey = process.env.AIRCODING_API_KEY || process.env.OPENAI_API_KEY
    const baseUrl = process.env.OPENAI_BASE_URL || process.env.AIRCODING_API_URL
    const model = process.env.AIRCODING_MODEL

    reports.push({
      name: 'provider.api_key',
      category: 'provider',
      passed: Boolean(apiKey),
      message: apiKey ? `API key set (${apiKey.slice(0, 7)}...)` : 'No API key set',
      fixable: false,
    })
    reports.push({
      name: 'provider.base_url',
      category: 'provider',
      passed: Boolean(baseUrl),
      message: baseUrl ? `Base URL: ${baseUrl}` : 'No base URL set',
      fixable: false,
    })
    reports.push({
      name: 'provider.model',
      category: 'provider',
      passed: Boolean(model),
      message: model || 'No model set',
      fixable: false,
    })

    if (apiKey && baseUrl) {
      try {
        const r = await fetch(`${baseUrl.replace(/\/$/, '')}/v1/models`, {
          method: 'GET',
          headers: { 'Authorization': `Bearer ${apiKey}` },
          signal: AbortSignal.timeout(5000),
        })
        reports.push({
          name: 'provider.connectivity',
          category: 'provider',
          passed: r.ok || r.status > 0,
          message: `HTTP ${r.status}`,
          fixable: false,
        })
      } catch (e: any) {
        reports.push({
          name: 'provider.connectivity',
          category: 'provider',
          passed: false,
          message: e.message,
          fixable: false,
        })
      }
    }
    return reports
  }
}