import fs from 'fs'
import path from 'path'

export default defineEventHandler(async (event) => {
  try {
    const body = await readBody(event)
    const { content, filename = 'openapi-custom.json', sourceType = 'custom' } = body
    
    if (!content) {
      throw createError({
        statusCode: 400,
        statusMessage: 'Content is required'
      })
    }
    
    // Validate that content is valid JSON
    let parsedContent
    try {
      if (typeof content === 'string') {
        parsedContent = JSON.parse(content)
      } else {
        parsedContent = content
      }
    } catch (error) {
      throw createError({
        statusCode: 400,
        statusMessage: 'Invalid JSON content: ' + error.message
      })
    }
    
    // Ensure docs directory exists
    const docsDir = path.join(process.cwd(), 'docs')
    if (!fs.existsSync(docsDir)) {
      fs.mkdirSync(docsDir, { recursive: true })
    }
    
    // Determine the correct filename based on source type
    let cleanFilename
    if (sourceType === 'collections') {
      cleanFilename = 'openapi-collection.json'
    } else if (sourceType === 'custom') {
      cleanFilename = 'openapi-custom.json'
    } else {
      // Clean the provided filename
      cleanFilename = filename.replace(/[^a-zA-Z0-9.-]/g, '_')
      if (!cleanFilename.endsWith('.json')) {
        cleanFilename += '.json'
      }
    }
    
    // Validate OpenAPI structure
    if (!parsedContent.openapi) {
      throw createError({
        statusCode: 400,
        statusMessage: 'Invalid OpenAPI specification: missing "openapi" field'
      })
    }
    
    if (!parsedContent.info) {
      throw createError({
        statusCode: 400,
        statusMessage: 'Invalid OpenAPI specification: missing "info" field'
      })
    }
    
    // Write file with formatted JSON
    const filePath = path.join(docsDir, cleanFilename)
    const formattedContent = JSON.stringify(parsedContent, null, 2)
    fs.writeFileSync(filePath, formattedContent, 'utf-8')
    
    // Determine the API URL based on the filename
    let apiUrl
    if (cleanFilename === 'openapi-collection.json') {
      apiUrl = '/openapi-coll.json'
    } else if (cleanFilename === 'openapi-custom.json') {
      apiUrl = '/openapi-custom.json'
    } else {
      apiUrl = `/docs/${cleanFilename}`
    }
    
    return {
      statusCode: 200,
      message: 'OpenAPI specification saved successfully',
      data: {
        filename: cleanFilename,
        path: `/docs/${cleanFilename}`,
        apiUrl: apiUrl,
        sourceType: sourceType,
        size: Buffer.byteLength(formattedContent, 'utf-8')
      }
    }
    
  } catch (error) {
    console.error('Error saving OpenAPI file:', error)
    
    // If it's already a createError, re-throw it
    if (error.statusCode) {
      throw error
    }
    
    throw createError({
      statusCode: 500,
      statusMessage: 'Failed to save file',
      data: {
        error: error.message
      }
    })
  }
})