#!/usr/bin/env node
/**
 * mizan Code Generator CLI
 *
 * Generate TypeScript types, React provider, and hooks from Django schemas.
 *
 * Usage:
 *   npx mizan-generate                    # Run once
 *   npx mizan-generate --watch            # Watch mode
 */

import { promises as fs } from 'fs'
import path from 'path'
import { fetchChannelsSchema, fetchMizanSchema } from './lib/fetch.mjs'
import { generateMizanFiles } from './lib/mizan.mjs'
import { generateChannelsFiles } from './lib/channels.mjs'
import { generateIndex } from './lib/index.mjs'

// Use cwd — the script runs via `npx mizan-generate` from the frontend root
const frontendDir = process.cwd()

/**
 * Load configuration from django.config.mjs
 */
async function loadConfig(configPath) {
  const fullPath = path.resolve(frontendDir, configPath)

  try {
    await fs.access(fullPath)
  } catch {
    throw new Error(`Config file not found: ${fullPath}`)
  }

  // Convert to file:// URL for Windows compatibility
  const fileUrl = new URL(`file://${fullPath.replace(/\\/g, '/')}`)

  if (configPath.endsWith('.mjs') || configPath.endsWith('.js')) {
    const module = await import(fileUrl)
    return module.default
  }

  if (configPath.endsWith('.ts')) {
    try {
      const module = await import(fileUrl)
      return module.default
    } catch {
      throw new Error(
        `Cannot load TypeScript config directly. Either:\n` +
        `  1. Install tsx: npm install -D tsx\n` +
        `  2. Use django.config.mjs instead`
      )
    }
  }

  throw new Error(`Unsupported config file format: ${configPath}`)
}

/**
 * Write generated code to file.
 */
async function writeOutput(filePath, content) {
  const dir = path.dirname(filePath)
  await fs.mkdir(dir, { recursive: true })
  await fs.writeFile(filePath, content, 'utf8')
}

/**
 * Run schema generation.
 */
async function generate(config, options = {}) {
  const { output } = options

  console.log('[mizan] Starting schema generation...')

  const outputPath = output || config.output || 'src/api/generated.ts'

  let channelsSchema = null
  let mizanSchema = null

  // Fetch and generate channels if available
  try {
    console.log('[mizan] Fetching channels schema...')
    channelsSchema = await fetchChannelsSchema(config.source, frontendDir)

    const channelCount = channelsSchema['x-mizan-channels']?.length || 0
    if (channelCount > 0) {
      console.log(`[mizan] Found ${channelCount} channels`)

      const channelsTypesPath = outputPath.replace(/\.ts$/, '.channels.ts')
      const fullChannelsTypesPath = path.resolve(frontendDir, channelsTypesPath)
      const channelsHooksPath = outputPath.replace(/\.ts$/, '.channels.hooks.tsx')
      const fullChannelsHooksPath = path.resolve(frontendDir, channelsHooksPath)
      const channelsSchemaPath = outputPath.replace(/\.ts$/, '.channels.schema.json')
      const fullChannelsSchemaPath = path.resolve(frontendDir, channelsSchemaPath)

      const { types: channelsTypes, hooks: channelsHooks } = await generateChannelsFiles(channelsSchema)

      console.log(`[mizan] Generating -> ${channelsTypesPath}`)
      await writeOutput(fullChannelsTypesPath, channelsTypes)

      if (channelsHooks) {
        console.log(`[mizan] Generating -> ${channelsHooksPath}`)
        await writeOutput(fullChannelsHooksPath, channelsHooks)
      }

      console.log(`[mizan] Generating -> ${channelsSchemaPath}`)
      await writeOutput(fullChannelsSchemaPath, JSON.stringify(channelsSchema, null, 2))
    } else {
      console.log('[mizan] No channels registered, skipping channels generation')
    }
  } catch (err) {
    console.log(`[mizan] Channels schema not available: ${err.message}`)
  }

  // Fetch and generate mizan files
  try {
    console.log('[mizan] Fetching mizan schema...')
    mizanSchema = await fetchMizanSchema(config.source, frontendDir)

    const functionCount = mizanSchema['x-mizan-functions']?.length || 0
    if (functionCount > 0) {
      console.log(`[mizan] Found ${functionCount} mizan functions`)

      const mizanTypesPath = outputPath.replace(/\.ts$/, '.mizan.ts')
      const fullMizanTypesPath = path.resolve(frontendDir, mizanTypesPath)
      const mizanProviderPath = outputPath.replace(/\.ts$/, '.provider.tsx')
      const fullMizanProviderPath = path.resolve(frontendDir, mizanProviderPath)
      const mizanServerPath = outputPath.replace(/\.ts$/, '.server.ts')
      const fullMizanServerPath = path.resolve(frontendDir, mizanServerPath)
      const mizanFormsPath = outputPath.replace(/\.ts$/, '.forms.ts')
      const fullMizanFormsPath = path.resolve(frontendDir, mizanFormsPath)
      const mizanSchemaPath = outputPath.replace(/\.ts$/, '.mizan.schema.json')
      const fullMizanSchemaPath = path.resolve(frontendDir, mizanSchemaPath)

      const hasChannels = (channelsSchema?.['x-mizan-channels']?.length || 0) > 0
      const { types: mizanTypes, provider: mizanProvider, server: mizanServer, forms: mizanForms } = await generateMizanFiles(mizanSchema, { hasChannels })

      console.log(`[mizan] Generating -> ${mizanTypesPath}`)
      await writeOutput(fullMizanTypesPath, mizanTypes)

      if (mizanProvider) {
        console.log(`[mizan] Generating -> ${mizanProviderPath}`)
        await writeOutput(fullMizanProviderPath, mizanProvider)
      }

      if (mizanServer) {
        console.log(`[mizan] Generating -> ${mizanServerPath}`)
        await writeOutput(fullMizanServerPath, mizanServer)
      }

      if (mizanForms) {
        console.log(`[mizan] Generating -> ${mizanFormsPath}`)
        await writeOutput(fullMizanFormsPath, mizanForms)
      }

      console.log(`[mizan] Generating -> ${mizanSchemaPath}`)
      await writeOutput(fullMizanSchemaPath, JSON.stringify(mizanSchema, null, 2))
    } else {
      console.log('[mizan] No mizan functions registered, skipping mizan generation')
    }
  } catch (err) {
    console.log(`[mizan] mizan schema not available: ${err.message}`)
  }

  // Generate consolidated index.ts
  const indexPath = path.dirname(outputPath) + '/index.ts'
  const fullIndexPath = path.resolve(frontendDir, indexPath)

  console.log(`[mizan] Generating -> ${indexPath}`)
  const indexContent = generateIndex({
    channelsSchema,
    mizanSchema,
  })
  await writeOutput(fullIndexPath, indexContent)

  console.log('[mizan] Generation complete!')
}

/**
 * Watch for changes and regenerate.
 */
async function watch(config, options) {
  const debounce = config.watch?.debounce || 1000
  let timeout = null
  let running = false

  async function runGenerate() {
    if (running) {
      timeout = setTimeout(runGenerate, debounce)
      return
    }

    running = true
    try {
      await generate(config, options)
    } catch (err) {
      console.error('[mizan] Generation failed:', err.message)
    } finally {
      running = false
    }
  }

  await runGenerate()

  console.log('[mizan] Watching for changes (press Ctrl+C to stop)...')

  if (config.source.django) {
    const { watch: chokidarWatch } = await import('chokidar')
    const djangoDir = path.resolve(frontendDir, path.dirname(config.source.django.managePath))

    const watcher = chokidarWatch([
      path.join(djangoDir, '**/*.py'),
    ], {
      ignored: [
        '**/node_modules/**',
        '**/__pycache__/**',
        '**/migrations/**',
        '**/.venv/**',
      ],
      ignoreInitial: true,
    })

    watcher.on('change', (filePath) => {
      console.log(`[mizan] Detected change: ${path.relative(djangoDir, filePath)}`)
      if (timeout) clearTimeout(timeout)
      timeout = setTimeout(runGenerate, debounce)
    })
  }

  process.on('SIGINT', () => {
    console.log('\n[mizan] Stopping watch mode...')
    process.exit(0)
  })
}

/**
 * Main entry point.
 */
async function main() {
  const args = process.argv.slice(2)

  let configPath = 'django.config.mjs'
  let watchMode = false
  let output = null

  for (let i = 0; i < args.length; i++) {
    if (args[i] === '--config' || args[i] === '-c') {
      configPath = args[++i]
    } else if (args[i] === '--watch' || args[i] === '-w') {
      watchMode = true
    } else if (args[i] === '--output' || args[i] === '-o') {
      output = args[++i]
    } else if (args[i] === '--help' || args[i] === '-h') {
      console.log(`
mizan Code Generator - Generate TypeScript from Django schemas

Usage:
  npx mizan-generate [options]

Options:
  -c, --config <path>   Config file path (default: django.config.mjs)
  -w, --watch           Watch mode - regenerate on changes
  -o, --output <path>   Output file path (overrides config)
  -h, --help            Show this help message
      `)
      process.exit(0)
    }
  }

  const config = await loadConfig(configPath)
  const options = { output }

  if (watchMode) {
    await watch(config, options)
  } else {
    await generate(config, options)
  }
}

main().catch(err => {
  console.error('[mizan] Error:', err.message)
  process.exit(1)
})