import { Exclude, Expose, Transform } from "class-transformer";
import {
  IsBoolean,
  IsEmail,
  IsISO8601,
  IsNotEmpty,
  IsOptional,
  IsString,
  MaxLength,
} from "class-validator";

/**
 * InboundEmailWebhookDto
 *
 * Shape posted by the AWS SES inbound-email Lambda after it parses an incoming
 * RFC 822 message. We deliberately keep the payload small and well-typed so the
 * Lambda has minimal logic to maintain — header extraction + a couple of body
 * cleanups, then POST.
 *
 * Required fields:
 *   - fromEmail   the sender's email address (parsed from the From: header)
 *   - message     the email body text (HTML stripped + reply-quote chains trimmed)
 *
 * Optional fields:
 *   - fromName    the sender's display name (parsed from the From: header).
 *                 If omitted, the API derives a fallback from the local-part of fromEmail.
 *   - subject     the email's Subject: header.
 *   - receivedAt  RFC 3339 timestamp from the Date: header. Falls back to API receipt time.
 *   - isAutoSubmitted  set by the Lambda when the email contained
 *                 Auto-Submitted: auto-replied (or similar). Tells us to skip the
 *                 visitor acknowledgement to avoid auto-reply ping-pong loops.
 *   - messageIdHeader  the Message-ID: header value. Currently not stored but
 *                 reserved for future thread-tracking features.
 */
@Exclude()
export class InboundEmailWebhookDto {
  @Expose()
  @IsEmail()
  @MaxLength(255)
  @Transform(({ value }) => (typeof value === "string" ? value.trim().toLowerCase() : value))
  fromEmail!: string;

  @Expose()
  @IsString()
  @IsOptional()
  @MaxLength(120)
  @Transform(({ value }) => (typeof value === "string" ? value.trim() : value))
  fromName?: string;

  @Expose()
  @IsString()
  @IsOptional()
  @MaxLength(500)
  @Transform(({ value }) => (typeof value === "string" ? value.trim() : value))
  subject?: string;

  @Expose()
  @IsString()
  @IsNotEmpty()
  @MaxLength(50000)
  @Transform(({ value }) => (typeof value === "string" ? value.trim() : value))
  message!: string;

  @Expose()
  @IsISO8601()
  @IsOptional()
  receivedAt?: string;

  @Expose()
  @IsBoolean()
  @IsOptional()
  isAutoSubmitted?: boolean;

  @Expose()
  @IsString()
  @IsOptional()
  @MaxLength(500)
  messageIdHeader?: string;
}