import { Metadata } from "next"
import { hash } from "bcryptjs"
import { createId } from "@paralleldrive/cuid2"
import { eq } from "drizzle-orm"

import type { ActionState } from "@/shared/types/action-state"
import { RegisterForm } from "@/modules/auth/components/register-form"

export const metadata: Metadata = {
  title: "Register - Next_Edu",
  description: "Create an account",
}

const normalizeBcryptHash = (value: string) => {
  if (value.startsWith("$2")) return value
  if (value.startsWith("$")) return `$2b${value}`
  return `$2b$${value}`
}

export default function RegisterPage() {
  async function registerAction(formData: FormData): Promise<ActionState> {
    "use server"

    const databaseUrl = process.env.DATABASE_URL
    if (!databaseUrl) return { success: false, message: "DATABASE_URL 未配置" }

    try {
      const [{ db }, { users }] = await Promise.all([
        import("@/shared/db"),
        import("@/shared/db/schema"),
      ])

      const name = String(formData.get("name") ?? "").trim()
      const email = String(formData.get("email") ?? "").trim().toLowerCase()
      const password = String(formData.get("password") ?? "")

      if (!email) return { success: false, message: "请输入邮箱" }
      if (!password) return { success: false, message: "请输入密码" }
      if (password.length < 6) return { success: false, message: "密码至少 6 位" }

      const existing = await db.query.users.findFirst({
        where: eq(users.email, email),
        columns: { id: true },
      })
      if (existing) return { success: false, message: "该邮箱已注册" }

      const hashedPassword = normalizeBcryptHash(await hash(password, 10))
      await db.insert(users).values({
        id: createId(),
        name: name.length ? name : null,
        email,
        password: hashedPassword,
        role: "student",
      })

      return { success: true, message: "账户创建成功" }
    } catch (error) {
      const isProd = process.env.NODE_ENV === "production"

      const anyErr = error as unknown as {
        code?: string
        message?: string
        sqlMessage?: string
        cause?: unknown
      }

      const cause1 = anyErr?.cause as
        | { code?: string; message?: string; sqlMessage?: string; cause?: unknown }
        | undefined
      const cause2 = (cause1?.cause ?? undefined) as
        | { code?: string; message?: string; sqlMessage?: string }
        | undefined

      const code = String(cause2?.code ?? cause1?.code ?? anyErr?.code ?? "").trim()
      const msg = String(
        cause2?.sqlMessage ??
          cause1?.sqlMessage ??
          anyErr?.sqlMessage ??
          cause2?.message ??
          cause1?.message ??
          anyErr?.message ??
          ""
      ).trim()
      const msgLower = msg.toLowerCase()

      if (
        code === "ER_DUP_ENTRY" ||
        msgLower.includes("duplicate") ||
        msgLower.includes("unique")
      ) {
        return { success: false, message: "该邮箱已注册" }
      }

      if (
        code === "ER_NO_SUCH_TABLE" ||
        msgLower.includes("doesn't exist") ||
        msgLower.includes("unknown column")
      ) {
        return {
          success: false,
          message: "数据库未初始化或未迁移，请先运行 npm run db:migrate",
        }
      }

      if (code === "ER_ACCESS_DENIED_ERROR") {
        return { success: false, message: "数据库账号/权限错误，请检查 DATABASE_URL" }
      }

      if (code === "ECONNREFUSED" || code === "ENOTFOUND") {
        return { success: false, message: "数据库连接失败，请检查 DATABASE_URL 与网络" }
      }

      if (!isProd && msg) {
        return { success: false, message: `创建账户失败：${msg}` }
      }

      return { success: false, message: "创建账户失败，请稍后重试" }
    }
  }

  return <RegisterForm registerAction={registerAction} />
}