import { createReadStream } from 'node:fs'
import { stat } from 'node:fs/promises'
import { defineConfig } from 'vite'
import { acceptedCardsRoot, resolveCardAssetRequest, scanCardCatalog } from './scripts/card-catalog.mjs'
import { readSurfaceDefaults, surfaceDefaultsPath, updateSurfaceDefaults } from './scripts/surface-defaults.mjs'

function json(response, status, value) {
  response.statusCode = status
  response.setHeader('Content-Type', 'application/json')
  response.setHeader('Cache-Control', 'no-store')
  response.end(JSON.stringify(value))
}
function readJsonBody(request) {
  return new Promise((resolve, reject) => {
    let body = ''
    request.setEncoding('utf8')
    request.on('data', chunk => {
      body += chunk
      if (body.length > 65536) reject(new Error('Request body is too large'))
    })
    request.on('end', () => {
      try { resolve(JSON.parse(body)) } catch { reject(new Error('Request body is not valid JSON')) }
    })
    request.on('error', reject)
  })
}
function installRoutes(server, writable) {
  let cachedCatalog
  let cachedAssetPaths
  let catalogPromise
  const catalog = async () => {
    if (cachedCatalog) return cachedCatalog
    catalogPromise ??= scanCardCatalog().then(value => {
      cachedCatalog = value
      cachedAssetPaths = new Set(value.cards.flatMap(card => Object.values(card.variants).flatMap(group =>
        Object.values(group).flatMap(asset => [asset.artwork, asset.mask, asset.textMask].filter(Boolean)
          .map(assetUrl => new URL(assetUrl, 'http://card-harness.local').pathname)))))
      return value
    }).finally(() => { catalogPromise = undefined })
    return catalogPromise
  }
  server.middlewares.use(async (request, response, next) => {
    const url = new URL(request.url ?? '/', 'http://card-harness.local')
    try {
      if (url.pathname === '/__card_catalog') return json(response, 200, await catalog())
      if (url.pathname === '/__surface_defaults') {
        if (request.method === 'GET') return json(response, 200, await readSurfaceDefaults(writable))
        if (request.method === 'POST' && writable) return json(response, 200, await updateSurfaceDefaults(await readJsonBody(request)))
        return json(response, 405, { error: 'Surface defaults are read-only in this server mode' })
      }
      if (url.pathname.startsWith('/__card_asset/')) {
        await catalog()
        if (!cachedAssetPaths?.has(url.pathname)) return json(response, 404, { error: 'Unknown card asset' })
        const path = await resolveCardAssetRequest(url.pathname)
        if (!path) return json(response, 404, { error: 'Unknown card asset' })
        const metadata = await stat(path)
        response.statusCode = 200
        response.setHeader('Content-Type', 'image/png')
        response.setHeader('Content-Length', String(metadata.size))
        response.setHeader('Cache-Control', url.searchParams.has('v') ? 'public, max-age=31536000, immutable' : 'no-cache')
        return createReadStream(path).pipe(response)
      }
      next()
    } catch (error) {
      const status = Number.isInteger(error?.statusCode) ? error.statusCode : 500
      json(response, status, { error: error instanceof Error ? error.message : String(error) })
    }
  })
  if (server.watcher) {
    server.watcher.add([acceptedCardsRoot, surfaceDefaultsPath])
    server.watcher.on('all', (_event, path) => {
      if (path.startsWith(acceptedCardsRoot)) {
        cachedCatalog = undefined
        cachedAssetPaths = undefined
        server.ws.send({ type: 'custom', event: 'card-catalog:update' })
      }
      if (path === surfaceDefaultsPath) server.ws.send({ type: 'custom', event: 'surface-defaults:update' })
    })
  }
}
function cardLibraryPlugin() {
  return {
    name: 'card-library',
    async buildStart() {
      const catalog = await scanCardCatalog()
      if (!catalog.cards.length || catalog.errors.length) {
        this.error(`Invalid accepted card catalog:\n${catalog.errors.join('\n') || 'No approved cards found'}`)
      }
    },
    configureServer(server) { installRoutes(server, true) },
    configurePreviewServer(server) { installRoutes(server, false) },
  }
}
export default defineConfig({ plugins: [cardLibraryPlugin()] })