import * as cdk from "aws-cdk-lib";
import * as budgets from "aws-cdk-lib/aws-budgets";
import { Construct } from "constructs";

export interface GovernanceTogglesProps {
  /** Monthly cost budget ceiling in USD. */
  readonly monthlyLimitUsd: number;
  /** Email that receives the budget threshold alerts. */
  readonly alertEmail: string;
}

/**
 * Account-level governance toggles expressible as CloudFormation. Adapted from
 * seahaven-account-baseline/lib/governance-toggles.ts.
 *
 * Provides a monthly AWS Budget with 80% / 100% actual + 100% forecast alerts.
 * Alerts go to a Sea Haven ops address (NOT the external dev team) so cost
 * surprises surface to the account owner.
 */
export class GovernanceToggles extends Construct {
  constructor(scope: Construct, id: string, props: GovernanceTogglesProps) {
    super(scope, id);

    const subscriber = [
      {
        subscriptionType: "EMAIL",
        address: props.alertEmail,
      },
    ];

    new budgets.CfnBudget(this, "MonthlyCostBudget", {
      budget: {
        budgetName: "seahaven-extdev-monthly-cost",
        budgetType: "COST",
        timeUnit: "MONTHLY",
        budgetLimit: {
          amount: props.monthlyLimitUsd,
          unit: "USD",
        },
      },
      notificationsWithSubscribers: [
        {
          notification: {
            notificationType: "ACTUAL",
            comparisonOperator: "GREATER_THAN",
            threshold: 80,
            thresholdType: "PERCENTAGE",
          },
          subscribers: subscriber,
        },
        {
          notification: {
            notificationType: "ACTUAL",
            comparisonOperator: "GREATER_THAN",
            threshold: 100,
            thresholdType: "PERCENTAGE",
          },
          subscribers: subscriber,
        },
        {
          notification: {
            notificationType: "FORECASTED",
            comparisonOperator: "GREATER_THAN",
            threshold: 100,
            thresholdType: "PERCENTAGE",
          },
          subscribers: subscriber,
        },
      ],
    });

    cdk.Annotations.of(this).addInfo(
      "Budget alerts: 80%/100% actual + 100% forecast of $" +
        props.monthlyLimitUsd +
        " to " +
        props.alertEmail
    );
  }
}