import { readFile } from "node:fs/promises"
import path from "node:path"
import { parse } from "yaml"
import { z } from "zod"

export const CONTACT_MAILER_CONFIG_PATH = path.join(
  process.cwd(),
  "config",
  "contact-mailer.yaml"
)

export class ContactMailerConfigError extends Error {}

function coerceBoolean(value: unknown) {
  if (typeof value === "boolean") {
    return value
  }

  if (typeof value === "string") {
    const normalized = value.trim().toLowerCase()

    if (normalized === "true") {
      return true
    }

    if (normalized === "false") {
      return false
    }
  }

  return value
}

function resolveEnvPlaceholders(value: unknown): unknown {
  if (typeof value === "string") {
    return value.replace(/\$\{([A-Z0-9_]+)(?::([^}]*))?\}/gi, (_, envName: string, fallback?: string) => {
      return process.env[envName] ?? fallback ?? ""
    })
  }

  if (Array.isArray(value)) {
    return value.map(resolveEnvPlaceholders)
  }

  if (value && typeof value === "object") {
    return Object.fromEntries(
      Object.entries(value).map(([key, nestedValue]) => [key, resolveEnvPlaceholders(nestedValue)])
    )
  }

  return value
}

const contactMailerConfigSchema = z.object({
  smtp: z.object({
    host: z.string().trim().min(1, "SMTP host 未配置"),
    port: z.coerce.number().int().positive("SMTP port 未配置"),
    secure: z.preprocess(coerceBoolean, z.boolean()),
    auth: z.object({
      user: z.string().trim().min(1, "SMTP 用户名未配置"),
      pass: z.string().min(1, "SMTP 密码未配置"),
    }),
    from: z.object({
      email: z.string().email("发件邮箱格式不正确"),
      name: z.string().trim().min(1).default("智店软件官网"),
    }),
  }),
  notification: z.object({
    to: z.array(z.string().email("通知邮箱格式不正确")).min(1).default(["bd@zhidiansoft.com"]),
    subjectPrefix: z.string().trim().min(1).default("官网线索"),
  }).default({
    to: ["bd@zhidiansoft.com"],
    subjectPrefix: "官网线索",
  }),
})

export type ContactMailerConfig = z.infer<typeof contactMailerConfigSchema>

export async function loadContactMailerConfig() {
  try {
    const fileContent = await readFile(CONTACT_MAILER_CONFIG_PATH, "utf8")
    const parsed = parse(fileContent) ?? {}
    const resolved = resolveEnvPlaceholders(parsed)

    return contactMailerConfigSchema.parse(resolved)
  } catch (error) {
    if (error instanceof z.ZodError) {
      throw new ContactMailerConfigError(
        `contact-mailer.yaml 配置不完整：${error.issues.map((issue) => issue.message).join("；")}`
      )
    }

    if (error instanceof Error) {
      throw new ContactMailerConfigError(`读取邮件配置失败：${error.message}`)
    }

    throw new ContactMailerConfigError("读取邮件配置失败")
  }
}