import type {
  NotificationClassification,
  NotificationHandlingMode,
  NotificationSourceMatcher,
  PushNotificationPayload,
} from "../../types";

const DEFAULT_SOURCE_MATCHER: Required<NotificationSourceMatcher> = {
  sourceKeys: ["source", "sdk_source", "vendor", "provider"],
  sourceValues: ["martech"],
  campaignIdKeys: ["sirrus_campaign_id", "sirrusCampaignId"],
  templateIdKeys: ["sirrus_template_id", "sirrusTemplateId"],
};

const getRawValue = (
  payload: PushNotificationPayload,
  key: string
): string | undefined => {
  const rawPayloadValue = payload.rawPayload?.[key];
  const dataValue = payload.data?.[key];

  if (typeof rawPayloadValue === "string") {
    return rawPayloadValue;
  }

  if (typeof dataValue === "string") {
    return dataValue;
  }

  return undefined;
};

const hasTaggedValue = (
  payload: PushNotificationPayload,
  keys: string[]
): { key: string; value: string } | null => {
  for (const key of keys) {
    const value = getRawValue(payload, key);
    if (value) {
      return { key, value };
    }
  }

  return null;
};

export class NotificationClassifier {
  constructor(
    private readonly handlingMode: NotificationHandlingMode,
    private readonly sourceMatcher: NotificationSourceMatcher = {}
  ) {}

  classify(payload: PushNotificationPayload): NotificationClassification {
    if (this.handlingMode === "all") {
      return {
        matched: true,
        ownership: "sirrus",
        reason: "Notification handling mode is set to all.",
      };
    }

    const matcher = {
      ...DEFAULT_SOURCE_MATCHER,
      ...this.sourceMatcher,
    };

    for (const key of matcher.sourceKeys) {
      const value = getRawValue(payload, key)?.toLowerCase();
      if (value && matcher.sourceValues.includes(value)) {
        return {
          matched: true,
          ownership: "sirrus",
          reason: `Matched Martech source marker from "${key}".`,
        };
      }
    }

    if (hasTaggedValue(payload, matcher.campaignIdKeys)) {
      return {
        matched: true,
        ownership: "sirrus",
        reason: "Matched campaign identifier.",
      };
    }

    if (hasTaggedValue(payload, matcher.templateIdKeys)) {
      return {
        matched: true,
        ownership: "sirrus",
        reason: "Matched template identifier.",
      };
    }

    if (payload.rawPayload || payload.data) {
      return {
        matched: false,
        ownership: "external",
        reason: "Notification payload did not include a Martech marker.",
      };
    }

    return {
      matched: false,
      ownership: "unknown",
      reason: "Notification payload did not contain structured metadata.",
    };
  }
}