import { randomUUID } from "node:crypto"
import { hasPermission } from "@cms/content/rbac"
import { createMediaAsset } from "@cms/db"

import { auth, resolveRoleFromAuthSession } from "@/lib/auth/server"
import { storeUpload } from "@/lib/media/storage"

export const runtime = "nodejs"

const MAX_UPLOAD_BYTES = Number(process.env.CMS_MEDIA_UPLOAD_MAX_BYTES ?? 25 * 1024 * 1024)

type AllowedRule = {
  mimePrefix?: string
  mimeExact?: string[]
}

const ALLOWED_MIME_BY_TYPE: Record<string, AllowedRule> = {
  artwork: {
    mimePrefix: "image/",
  },
  banner: {
    mimePrefix: "image/",
  },
  promotion: {
    mimePrefix: "image/",
  },
  video: {
    mimePrefix: "video/",
  },
  gif: {
    mimeExact: ["image/gif"],
  },
  generic: {
    mimePrefix: "",
  },
}

function parseTextField(formData: FormData, field: string): string {
  const value = formData.get(field)
  return typeof value === "string" ? value.trim() : ""
}

function parseOptionalField(formData: FormData, field: string): string | undefined {
  const value = parseTextField(formData, field)
  return value.length > 0 ? value : undefined
}

function parseTags(formData: FormData): string[] {
  const value = parseTextField(formData, "tags")

  if (!value) {
    return []
  }

  return value
    .split(",")
    .map((item) => item.trim())
    .filter((item) => item.length > 0)
}

function deriveTitleFromFilename(fileName: string): string {
  const trimmed = fileName.trim()

  if (!trimmed) {
    return "Untitled media"
  }

  const dotIndex = trimmed.lastIndexOf(".")
  const base = dotIndex > 0 ? trimmed.slice(0, dotIndex) : trimmed
  const normalized = base.trim()

  return normalized.length > 0 ? normalized : "Untitled media"
}

function isMimeAllowed(mediaType: string, mimeType: string): boolean {
  const rule = ALLOWED_MIME_BY_TYPE[mediaType]

  if (!rule) {
    return false
  }

  if (rule.mimeExact?.includes(mimeType)) {
    return true
  }

  if (rule.mimePrefix === "") {
    return true
  }

  return rule.mimePrefix ? mimeType.startsWith(rule.mimePrefix) : false
}

function badRequest(message: string): Response {
  return Response.json(
    {
      message,
    },
    { status: 400 },
  )
}

export async function POST(request: Request): Promise<Response> {
  const session = await auth.api
    .getSession({
      headers: request.headers,
    })
    .catch(() => null)
  const role = resolveRoleFromAuthSession(session)

  if (!role) {
    return Response.json(
      {
        message: "Unauthorized",
      },
      { status: 401 },
    )
  }

  if (!hasPermission(role, "media:write", "team")) {
    return Response.json(
      {
        message: "Missing permission: media:write",
      },
      { status: 403 },
    )
  }

  const formData = await request.formData().catch(() => null)

  if (!formData) {
    return badRequest("Invalid form payload.")
  }

  const type = parseTextField(formData, "type")
  const fileEntry = formData.get("file")

  if (!type) {
    return badRequest("Type is required.")
  }

  if (!(fileEntry instanceof File)) {
    return badRequest("File is required.")
  }

  if (fileEntry.size === 0) {
    return badRequest("File is empty.")
  }

  if (fileEntry.size > MAX_UPLOAD_BYTES) {
    return badRequest(
      `File is too large. Maximum upload is ${Math.floor(MAX_UPLOAD_BYTES / 1024 / 1024)} MB.`,
    )
  }

  if (!isMimeAllowed(type, fileEntry.type)) {
    return badRequest(`File type ${fileEntry.type || "unknown"} is not allowed for ${type}.`)
  }

  const title = parseTextField(formData, "title") || deriveTitleFromFilename(fileEntry.name)
  const mediaAssetId = randomUUID()
  const variant = "original"
  const fileRole = "original"

  try {
    const stored = await storeUpload({
      file: fileEntry,
      assetId: mediaAssetId,
      variant,
      fileRole,
    })

    const created = await createMediaAsset({
      id: mediaAssetId,
      title,
      type,
      description: parseOptionalField(formData, "description"),
      altText: parseOptionalField(formData, "altText"),
      source: parseOptionalField(formData, "source"),
      copyright: parseOptionalField(formData, "copyright"),
      author: parseOptionalField(formData, "author"),
      tags: parseTags(formData),
      storageKey: stored.storageKey,
      mimeType: fileEntry.type || undefined,
      sizeBytes: fileEntry.size,
      isPublished: parseTextField(formData, "isPublished") === "true",
    })

    return Response.json(
      {
        id: created.id,
        provider: stored.provider,
        warning: stored.fallbackReason,
        notice: "Media uploaded successfully.",
      },
      { status: 201 },
    )
  } catch (error) {
    const message = error instanceof Error ? error.message : "Upload failed. Please try again."

    return Response.json(
      {
        message,
      },
      { status: 500 },
    )
  }
}