/**
 * Download images from legacy Parmin storage URLs and re-upload to our Parspack S3.
 * Updates Product/BlogPost imageUrl + imageKey, and rewrites URLs inside blog bodies.
 *
 * Usage:
 *   npx ts-node -r tsconfig-paths/register scripts/migrate-images-to-s3.ts
 */
import { createHash, randomUUID } from 'crypto'
import { extname } from 'path'
import { PrismaClient } from '@prisma/client'
import { config as loadEnv } from 'dotenv'
import { PutObjectCommand, S3Client } from '@aws-sdk/client-s3'
import {
  blogMediaKey,
  productMainKey,
} from '../src/storage/storage-keys'

loadEnv()

const prisma = new PrismaClient()

const LEGACY_HOST_RE =
  /madomotor\.sas\.amin\.parminstorage\.ir|sas\.amin\.parminstorage\.ir/i

const EXT_MIME: Record<string, string> = {
  '.jpg': 'image/jpeg',
  '.jpeg': 'image/jpeg',
  '.png': 'image/png',
  '.webp': 'image/webp',
  '.gif': 'image/gif',
}

function requireEnv(name: string): string {
  const v = process.env[name]
  if (!v) throw new Error(`Missing env ${name}`)
  return v
}

function publicUrlBase(): string {
  return requireEnv('S3_PUBLIC_URL').replace(/\/$/, '')
}

function isAlreadyOurs(url: string | null | undefined): boolean {
  if (!url) return false
  return url.startsWith(publicUrlBase())
}

function isLegacyUrl(url: string): boolean {
  try {
    const u = new URL(url)
    return LEGACY_HOST_RE.test(u.hostname)
  } catch {
    return false
  }
}

function guessExt(url: string, contentType: string | null): string {
  const pathPart = decodeURIComponent(new URL(url).pathname)
  const fromUrl = extname(pathPart).toLowerCase()
  if (fromUrl && fromUrl.length <= 5) return fromUrl
  if (contentType?.includes('png')) return '.png'
  if (contentType?.includes('webp')) return '.webp'
  if (contentType?.includes('gif')) return '.gif'
  return '.jpg'
}

function mimeFor(ext: string, contentType: string | null): string {
  if (contentType && contentType.startsWith('image/')) {
    return contentType.split(';')[0].trim()
  }
  return EXT_MIME[ext] ?? 'image/jpeg'
}

function extractUrls(text: string): string[] {
  const found = new Set<string>()
  const patterns = [
    /https?:\/\/[^\s"'<>]+/g,
    /src=["'](https?:\/\/[^"']+)["']/gi,
  ]
  for (const re of patterns) {
    for (const match of text.matchAll(re)) {
      const url = (match[1] ?? match[0]).replace(/&amp;/g, '&')
      found.add(url)
    }
  }
  return [...found]
}

type Kind = 'product' | 'blog' | 'blog-body'

function encodeFetchUrl(url: string): string {
  try {
    const u = new URL(url)
    // Encode each path segment so Persian filenames download reliably
    u.pathname = u.pathname
      .split('/')
      .map((seg) => {
        if (!seg) return seg
        try {
          return encodeURIComponent(decodeURIComponent(seg))
        } catch {
          return encodeURIComponent(seg)
        }
      })
      .join('/')
    return u.toString()
  } catch {
    return encodeURI(url)
  }
}

async function download(url: string): Promise<{
  buffer: Buffer
  contentType: string | null
}> {
  const candidates = [url, encodeFetchUrl(url)]
  let lastError: Error | null = null

  for (const candidate of candidates) {
    try {
      const res = await fetch(candidate, {
        redirect: 'follow',
        headers: {
          'User-Agent': 'mado-motor-image-migrator/1.0',
          Accept: 'image/*,*/*',
        },
      })
      if (!res.ok) {
        lastError = new Error(`HTTP ${res.status} for ${candidate}`)
        continue
      }
      const contentType = res.headers.get('content-type')
      const buffer = Buffer.from(await res.arrayBuffer())
      if (buffer.length < 32) {
        lastError = new Error(`Tiny response (${buffer.length}b) for ${candidate}`)
        continue
      }
      return { buffer, contentType }
    } catch (err) {
      lastError = err instanceof Error ? err : new Error(String(err))
    }
  }

  throw lastError ?? new Error(`Failed to download ${url}`)
}

async function main() {
  const endpoint = requireEnv('S3_ENDPOINT')
  const bucket = requireEnv('S3_BUCKET')
  const base = publicUrlBase()

  const client = new S3Client({
    endpoint,
    region: process.env.S3_REGION || 'us-east-1',
    forcePathStyle: (process.env.S3_FORCE_PATH_STYLE || 'true') === 'true',
    credentials: {
      accessKeyId: requireEnv('S3_ACCESS_KEY_ID'),
      secretAccessKey: requireEnv('S3_SECRET_ACCESS_KEY'),
    },
  })

  const products = await prisma.product.findMany({
    select: { id: true, imageUrl: true, imageKey: true },
  })
  const blogs = await prisma.blogPost.findMany({
    select: { id: true, imageUrl: true, imageKey: true, body: true },
  })

  type Job = { url: string; kind: Kind; entityId?: string }
  const jobs: Job[] = []
  const seen = new Set<string>()

  const enqueue = (url: string, kind: Kind, entityId?: string) => {
    const clean = url.replace(/[),.;]+$/, '')
    if (!isLegacyUrl(clean) || isAlreadyOurs(clean)) return
    if (seen.has(clean)) return
    seen.add(clean)
    jobs.push({ url: clean, kind, entityId })
  }

  for (const p of products) {
    if (p.imageUrl) enqueue(p.imageUrl, 'product', p.id)
  }
  for (const b of blogs) {
    if (b.imageUrl) enqueue(b.imageUrl, 'blog', b.id)
    for (const u of extractUrls(b.body || '')) {
      enqueue(u, 'blog-body')
    }
  }

  console.log(`Found ${jobs.length} unique legacy URLs to migrate`)

  const urlMap = new Map<string, { url: string; key: string }>()
  let ok = 0
  let failed = 0

  for (const [i, job] of jobs.entries()) {
    const label = `[${i + 1}/${jobs.length}]`
    try {
      const { buffer, contentType } = await download(job.url)
      const ext = guessExt(job.url, contentType)
      const fileName = `${randomUUID()}${ext}`
      const key =
        job.kind === 'product'
          ? productMainKey(fileName)
          : blogMediaKey(
              job.kind === 'blog-body' ? `body/${fileName}` : fileName,
            )
      const contentTypeFinal = mimeFor(ext, contentType)

      await client.send(
        new PutObjectCommand({
          Bucket: bucket,
          Key: key,
          Body: buffer,
          ContentType: contentTypeFinal,
        }),
      )

      const publicUrl = `${base}/${key}`
      urlMap.set(job.url, { url: publicUrl, key })

      // also map common encoded/decoded variants
      try {
        urlMap.set(decodeURI(job.url), { url: publicUrl, key })
      } catch {
        /* ignore */
      }
      urlMap.set(encodeURI(decodeURIComponent(job.url)), {
        url: publicUrl,
        key,
      })

      ok += 1
      const hash = createHash('sha1').update(buffer).digest('hex').slice(0, 8)
      console.log(
        `${label} OK ${job.kind} ${buffer.length}b ${hash} → ${key}`,
      )
    } catch (err) {
      failed += 1
      console.error(
        `${label} FAIL ${job.url}`,
        err instanceof Error ? err.message : err,
      )
    }
  }

  // Update products
  let productsUpdated = 0
  for (const p of products) {
    if (!p.imageUrl) continue
    const mapped = urlMap.get(p.imageUrl) || urlMap.get(p.imageUrl.replace(/[),.;]+$/, ''))
    if (!mapped) continue
    await prisma.product.update({
      where: { id: p.id },
      data: { imageUrl: mapped.url, imageKey: mapped.key },
    })
    productsUpdated += 1
  }

  // Update blogs (cover + body rewrite)
  let blogsUpdated = 0
  for (const b of blogs) {
    let body = b.body || ''
    let changed = false

    for (const [oldUrl, mapped] of urlMap) {
      if (body.includes(oldUrl)) {
        body = body.split(oldUrl).join(mapped.url)
        changed = true
      }
    }

    // also rewrite any remaining legacy host URLs that we mapped by pathname
    const stillLegacy = extractUrls(body).filter(isLegacyUrl)
    for (const u of stillLegacy) {
      const clean = u.replace(/[),.;]+$/, '')
      const mapped = urlMap.get(clean)
      if (mapped && body.includes(u)) {
        body = body.split(u).join(mapped.url)
        changed = true
      }
    }

    const coverMapped = b.imageUrl
      ? urlMap.get(b.imageUrl) ||
        urlMap.get(b.imageUrl.replace(/[),.;]+$/, ''))
      : undefined

    if (!changed && !coverMapped) continue

    await prisma.blogPost.update({
      where: { id: b.id },
      data: {
        ...(coverMapped
          ? { imageUrl: coverMapped.url, imageKey: coverMapped.key }
          : {}),
        ...(changed ? { body } : {}),
      },
    })
    blogsUpdated += 1
  }

  console.log('Done:', {
    migrated: ok,
    failed,
    productsUpdated,
    blogsUpdated,
    publicBase: base,
  })
}

main()
  .catch((err) => {
    console.error(err)
    process.exitCode = 1
  })
  .finally(async () => {
    await prisma.$disconnect()
  })