import type { TriggerDefinition } from "../types"
import type { HttpTriggerScope } from "./core-http"
import * as z from "zod/mini"

const MAX_EMAIL_LOCAL_PART_BYTES = 64
const EMAIL_SCHEMA = z.email()
const MAILHOOK_PRESENTATION_CONFIG_SCHEMA = z.object({
  scope: z.prefault(z.enum(["trigger", "automation", "project"]), "trigger"),
})

export const PLATFORM_EMAIL_DOMAIN = "automations.automate.ax"

export const mailhookEmailReceivedTriggerDefinition = {
  getPrimary: ({ automationId, config, hookSlot, projectId, scopePath }) => ({
    copyable: true,
    value: getMailhookAddress({
      automationId,
      hookSlot,
      projectId,
      scope: MAILHOOK_PRESENTATION_CONFIG_SCHEMA.parse(config).scope,
      scopePath,
    }),
  }),
  icon: "webhook",
  name: "Mailhook",
  type: "mailhook.email.received",
} as const satisfies TriggerDefinition

export type MailhookScope = HttpTriggerScope

export interface MailhookAddressOptions {
  automationId: string
  hookSlot: number
  plusPath?: string
  projectId: string
  scope: MailhookScope
  scopePath?: readonly number[]
}

/**
 * Returns the unique inbound address for one deployed mailhook.
 *
 * Add `+suffix` before the `@` to carry a routing value into the event.
 *
 * @param options - Mailhook identity and sharing scope.
 * @throws When the generated local part exceeds the email size limit.
 */
export function getMailhookAddress(options: MailhookAddressOptions) {
  const localPart = `${getMailhookAddressKey(options)}${options.plusPath ? `+${options.plusPath}` : ""}`
  if (new TextEncoder().encode(localPart).length > MAX_EMAIL_LOCAL_PART_BYTES) {
    throw new RangeError("Mailhook address local part exceeds 64 bytes.")
  }

  return EMAIL_SCHEMA.parse(`${localPart}@${PLATFORM_EMAIL_DOMAIN}`)
}

/**
 * Returns the local-part router key for one configured mailhook scope.
 *
 * @param options - Mailhook identity and sharing scope.
 */
export function getMailhookAddressKey(options: MailhookAddressOptions) {
  if (options.scope === "project") return `p${typeIdSuffix(options.projectId)}`
  if (options.scope === "automation") {
    return `a${typeIdSuffix(options.automationId)}`
  }

  return `a${typeIdSuffix(options.automationId)}.${[
    ...(options.scopePath ?? []),
    options.hookSlot,
  ]
    .map((segment) => segment.toString(36))
    .join(".")}`
}

/**
 * Removes the redundant TypeID prefix from an address router.
 *
 * @param id - Project or automation TypeID.
 */
function typeIdSuffix(id: string) {
  return id.includes("_") ? id.slice(id.indexOf("_") + 1) : id
}