import * as cdk from "aws-cdk-lib";
import * as kms from "aws-cdk-lib/aws-kms";
import * as iam from "aws-cdk-lib/aws-iam";
import * as events from "aws-cdk-lib/aws-events";
import * as backup from "aws-cdk-lib/aws-backup";
import { Construct } from "constructs";

/**
 * Primary AWS Backup vault + plan for Sea Haven (account 328440206208), us-east-1.
 *
 * Closes audit finding C-7 (AWS Backup entirely unused) together with
 * backup-offsite-stack. Phase 1 ("critical data first"): protect the data
 * stores with no offsite leg today and copy each recovery point cross-region
 * to the GOVERNANCE-locked `seahaven-offsite` vault (us-west-2).
 *
 * Coexistence: this SUPPLEMENTS the existing EBS DLM snapshots and DynamoDB
 * PITR — it does not replace them. It adds the missing Copy3 (offsite) +
 * immutability leg. The DLM/PITR overlap is rationalized in a later phase.
 *
 * Selection is by explicit ARN (not tag-based) so we don't have to tag — and
 * drift — resources owned by other stacks (proposal-system, payments-dashboard).
 * Switch to tag-based selection when expanding past the phase-1 set.
 *
 * PRE-DEPLOY GATES (validate before the first scheduled run):
 *  - S3 backup requires bucket versioning. `accounting.seahaven.com` already
 *    has it (audit C-9); `seahaven-payments-csv-328440206208` and
 *    `google-workspace-seahavenind.com` must have versioning enabled first or
 *    their jobs fail silently (folds in audit H-21).
 *  - `database-1` is unencrypted (audit H-19). Cross-region copy of an
 *    unencrypted RDS recovery point may fail or land unencrypted. Smoke-test
 *    an on-demand backup of `database-1` FIRST and confirm the copy job to
 *    us-west-2 succeeds; if not, encrypt database-1 (H-19) or drop it from the
 *    copy until then.
 *  - DynamoDB PITR (H-7) is independent of this plan; enable it on the two
 *    tables for between-window point-in-time recovery.
 */
export class BackupStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // CMK encrypting the primary (operational) vault. RETAIN + rotation.
    const vaultKey = new kms.Key(this, "PrimaryVaultKey", {
      alias: "backup-primary-vault",
      description: "Encrypts primary AWS Backup recovery points (us-east-1)",
      enableKeyRotation: true,
      removalPolicy: cdk.RemovalPolicy.RETAIN,
    });

    // The L2 BackupVault does NOT grant the backup service use of a customer
    // CMK; the default key policy only delegates to account IAM. Grant
    // backup.amazonaws.com the minimum KMS actions (incl. CreateGrant for
    // RDS/EBS recovery points) so backup jobs can write to this vault.
    vaultKey.addToResourcePolicy(
      new iam.PolicyStatement({
        sid: "AllowAwsBackupUseOfTheKey",
        principals: [new iam.ServicePrincipal("backup.amazonaws.com")],
        // Action set matches AWS's documented Backup vault-key policy; scoped
        // to this account so only this account's Backup service can use it.
        actions: [
          "kms:Decrypt",
          "kms:GenerateDataKey",
          "kms:GenerateDataKeyWithoutPlaintext",
          "kms:ReEncrypt*",
          "kms:DescribeKey",
        ],
        resources: ["*"],
        conditions: { StringEquals: { "aws:SourceAccount": this.account } },
      })
    );
    vaultKey.addToResourcePolicy(
      new iam.PolicyStatement({
        sid: "AllowAwsBackupCreateGrant",
        principals: [new iam.ServicePrincipal("backup.amazonaws.com")],
        actions: ["kms:CreateGrant"],
        resources: ["*"],
        conditions: {
          Bool: { "kms:GrantIsForAWSResource": "true" },
          StringEquals: { "aws:SourceAccount": this.account },
        },
      })
    );

    // Primary vault — GOVERNANCE Vault Lock (INFRA-89). Codifies the lock applied
    // out-of-band 2026-06: MinRetention 1d, MaxRetention 2555d (~7y), no
    // `changeableFor` (LockDate null = admin-removable, GOVERNANCE not
    // COMPLIANCE) so it stays adjustable while the plan is validated. This block
    // is written to MATCH the live lock exactly, so the deploy diff is a no-op
    // adoption — it does not change the live vault.
    //
    // NOTE: the scoped vault access policy is (re)introduced below (INFRA-94)
    // with the fix for the two lockout-class bugs that got it split out of
    // INFRA-89: the deny statement now exempts THREE principals via
    // StringNotLike on aws:PrincipalArn — the SSO AdministratorAccess role (break
    // glass), the backup service role, AND the CDK CFN execution role. The
    // CFN-exec-role exemption is MANDATORY: without it CloudFormation cannot
    // re-assert the vault lock config / manage the vault and the deploy strands
    // the policy (this happened 2026-06-08). NotPrincipal is deliberately NOT
    // used (it rejects wildcard ARNs). Governance lock codify + backup
    // selections land here.
    const primaryVault = new backup.BackupVault(this, "PrimaryVault", {
      backupVaultName: "seahaven-primary",
      encryptionKey: vaultKey,
      removalPolicy: cdk.RemovalPolicy.RETAIN,
      lockConfiguration: {
        minRetention: cdk.Duration.days(1),
        maxRetention: cdk.Duration.days(2555),
        // No `changeableFor` → GOVERNANCE mode, admin-removable (matches live).
      },
    });

    // Vault access policy (INFRA-94): Deny the destructive recovery-point and
    // vault-lifecycle actions to EVERY principal EXCEPT the three operational
    // identities below. This is defense-in-depth on top of the GOVERNANCE lock —
    // it blocks manual deletion / lifecycle tampering even from accounts that
    // hold the equivalent IAM permissions.
    //
    // Deny (not Allow): a resource-policy Deny overrides any identity-based
    // Allow, which is exactly what we want for a guardrail. The StringNotLike
    // condition means "this Deny applies UNLESS the caller's ARN matches one of
    // the exempted patterns" — i.e. the three exempt principals are NOT denied.
    //
    // Exemptions (all THREE required):
    //  1. SSO AdministratorAccess role — break-glass human admin path. Matched by
    //     wildcard because the AWSReservedSSO role name carries a permission-set
    //     hash suffix.
    //  2. seahaven-backup-service-role — AWS Backup uses it for lifecycle
    //     expiry of recovery points; denying it would break the plan's
    //     deleteAfter cleanup.
    //  3. cdk-hnb659fds-cfn-exec-role — the CloudFormation execution role. CFN
    //     re-asserts the vault lock config and manages the vault on every deploy;
    //     omitting it strands the policy and fails the deploy (INFRA-94,
    //     2026-06-08). Wildcard-suffixed to cover the region-qualified name.
    //
    // NotPrincipal is intentionally avoided — it does not accept wildcard ARNs.
    primaryVault.addToAccessPolicy(
      new iam.PolicyStatement({
        sid: "DenyDestructiveActionsExceptOperationalRoles",
        effect: iam.Effect.DENY,
        principals: [new iam.AnyPrincipal()],
        actions: [
          "backup:DeleteRecoveryPoint",
          "backup:UpdateRecoveryPointLifecycle",
          "backup:DeleteBackupVault",
          "backup:DeleteBackupVaultAccessPolicy",
          "backup:DeleteBackupVaultLockConfiguration",
          "backup:PutBackupVaultLockConfiguration",
        ],
        resources: ["*"],
        conditions: {
          StringNotLike: {
            "aws:PrincipalArn": [
              // 1. SSO AdministratorAccess (break-glass human admin)
              `arn:aws:iam::${this.account}:role/aws-reserved/sso.amazonaws.com/*AWSReservedSSO_AdministratorAccess*`,
              // 2. AWS Backup service role (lifecycle expiry of recovery points)
              `arn:aws:iam::${this.account}:role/seahaven-backup-service-role`,
              // 3. CDK CloudFormation execution role (MANDATORY — manages vault)
              `arn:aws:iam::${this.account}:role/cdk-hnb659fds-cfn-exec-role-*`,
            ],
          },
        },
      })
    );

    // Cross-region copy destination, referenced by literal ARN (the offsite
    // stack is in another region; a literal ARN avoids crossRegionReferences /
    // SSM exports). Stack ordering is enforced via addStackDependency in bin/app.ts.
    const offsiteVault = backup.BackupVault.fromBackupVaultArn(
      this,
      "OffsiteVaultRef",
      `arn:aws:backup:us-west-2:${this.account}:backup-vault:seahaven-offsite`
    );

    // AWS Backup service role. Explicit (not auto-generated) because S3 backup
    // needs the S3-specific managed policy on top of the standard backup one.
    // Least-privilege: BACKUP + S3-backup only. Restore policies
    // (AWSBackupServiceRolePolicyForRestores / ...ForS3Restore) and
    // BackupSelection allowRestores are intentionally NOT granted — restores
    // are a deliberate, audited action and will get their own scoped role/path
    // once a restore-test process exists (cross-review F-1/F-2). A known role
    // name lets the deploy role's iam:PassRole be scoped to this exact ARN.
    // NOTE: creating this role is an IAM change → Sea Haven cross-review gate.
    const backupRole = new iam.Role(this, "BackupRole", {
      roleName: "seahaven-backup-service-role",
      assumedBy: new iam.ServicePrincipal("backup.amazonaws.com"),
      description: "AWS Backup service role (backup-only) for seahaven-primary",
      managedPolicies: [
        iam.ManagedPolicy.fromAwsManagedPolicyName(
          "service-role/AWSBackupServiceRolePolicyForBackup"
        ),
        iam.ManagedPolicy.fromAwsManagedPolicyName(
          "AWSBackupServiceRolePolicyForS3Backup"
        ),
      ],
    });

    // Daily backup → primary vault (35d), cross-region copy → offsite (90d).
    const plan = new backup.BackupPlan(this, "Plan", {
      backupPlanName: "seahaven-critical-daily",
      backupVault: primaryVault,
      backupPlanRules: [
        new backup.BackupPlanRule({
          ruleName: "daily-crr-offsite",
          backupVault: primaryVault,
          // 06:00 UTC — offset from the file-share DLM run.
          scheduleExpression: events.Schedule.cron({ hour: "6", minute: "0" }),
          startWindow: cdk.Duration.hours(1),
          completionWindow: cdk.Duration.hours(6),
          deleteAfter: cdk.Duration.days(35),
          copyActions: [
            {
              destinationBackupVault: offsiteVault,
              deleteAfter: cdk.Duration.days(90),
            },
          ],
        }),
      ],
    });

    // Phase-1 critical set, by explicit ARN (identifiers verified against the
    // live account 2026-05-29).
    plan.addSelection("CriticalResources", {
      backupSelectionName: "critical-data",
      role: backupRole,
      // allowRestores omitted (defaults false) — backup-only, see role comment.
      resources: [
        // RDS. database-1 was retired 2026-06-03 (audit H-19: idle SQL Server
        // Express, snapshot-and-delete) — its final recovery point lives in the
        // offsite vault; removed from the selection so backup jobs don't fail on
        // a missing resource.
        backup.BackupResource.fromArn(
          `arn:aws:rds:us-east-1:${this.account}:db:proposal-system-db`
        ),
        // DynamoDB (financial)
        backup.BackupResource.fromArn(
          `arn:aws:dynamodb:us-east-1:${this.account}:table/PaymentsDashboard`
        ),
        backup.BackupResource.fromArn(
          `arn:aws:dynamodb:us-east-1:${this.account}:table/purchase-orders`
        ),
        // S3 (single-copy critical buckets) — versioning required (see header)
        backup.BackupResource.fromArn("arn:aws:s3:::accounting.seahaven.com"),
        backup.BackupResource.fromArn(
          "arn:aws:s3:::seahaven-payments-csv-328440206208"
        ),
        backup.BackupResource.fromArn(
          "arn:aws:s3:::google-workspace-seahavenind.com"
        ),
      ],
    });

    // Phase-2 expansion (audit Day 4): bring the remaining DynamoDB tables and
    // all in-use EBS volumes under the same daily plan + cross-region copy to
    // the locked offsite vault ("offsite for everything"). Same role and rule
    // as phase-1; a separate selection keeps the phase-1 critical set readable.
    //
    // Still EXPLICIT-ARN (not tag-based) on purpose: the file-share volumes are
    // standalone CDK-managed (RETAIN) and the DynamoDB tables are owned by other
    // stacks, so tagging them here would drift those stacks — the same reason
    // phase-1 avoided tags. Tradeoff: if a volume is replaced (new vol-id) it
    // silently drops from this selection; scheduled drift detection + the audit
    // re-run are the backstop. Identifiers verified against the live account
    // 2026-06-03.
    //
    // Excluded by intent: the ledgerflow tables — the whole LedgerFlow stack
    // was decommissioned 2026-06-03 (audit Day 4), so they no longer exist.
    // database-1 was retired the same day and removed from the phase-1 selection
    // above (audit H-19).
    plan.addSelection("Phase2Resources", {
      backupSelectionName: "phase2-offsite-everything",
      role: backupRole,
      resources: [
        // DynamoDB — all remaining tables (10)
        ...[
          "SiteAssignments",
          "VendorReplies",
          "WorkOrderComments",
          "WorkOrders",
          "afterhours-shifts",
          "front-sla-alerts",
          "last-war-bot",
          "meal-order-manager-orders",
          "pending-site-review",
          "verified-sites",
        ].map((t) =>
          backup.BackupResource.fromArn(
            `arn:aws:dynamodb:us-east-1:${this.account}:table/${t}`
          )
        ),
        // EBS — remaining in-use volumes (unencrypted sources land encrypted at
        // the vault CMK, as the C-7 database-1 smoke-test confirmed)
        ...[
          "vol-05cb0eb5c145d799b", // SeaHavenIndustries-dev
          "vol-054cf918f227d88f6", // file-share (20 GiB)
          "vol-00f05a5a809697ce5", // forgejo
          "vol-04d951cccacc435b5", // file-share NAS (500 GiB)
          "vol-07094902194638fff", // syslog-server
          "vol-0c2cbe9e71517a517", // Mutual Aid Data
          "vol-0fe224f13812f47e7", // jump box
          "vol-0f0c167f3d7f85542", // last-war-rankings
        ].map((v) =>
          backup.BackupResource.fromArn(
            `arn:aws:ec2:us-east-1:${this.account}:volume/${v}`
          )
        ),
        // S3 — additional critical/PII buckets (INFRA-88). Explicit-ARN, same as
        // the phase-1 set. Versioning verified enabled on all 6 against the live
        // account 2026-06-08 (S3 backup requires versioning). payroll-emails is
        // PII → immutable offsite copy is the point of including it.
        ...[
          "seahaven-kb-docs-328440206208",
          "seahaven-payroll-emails-328440206208",
          "amazon-po",
          "extracted-amazon-po",
          "proposal-system-uploads-328440206208",
          "proposal-system-generated-328440206208",
        ].map((b) => backup.BackupResource.fromArn(`arn:aws:s3:::${b}`)),
      ],
    });

    cdk.Tags.of(this).add("Project", "account-baseline");
    cdk.Tags.of(this).add("Owner", "adam@seahavenind.com");
    cdk.Tags.of(this).add("Environment", "prod");
    cdk.Tags.of(this).add("ManagedBy", "cdk");

    new cdk.CfnOutput(this, "PrimaryVaultName", { value: "seahaven-primary" });
    new cdk.CfnOutput(this, "PrimaryVaultKmsKeyArn", { value: vaultKey.keyArn });
    new cdk.CfnOutput(this, "BackupPlanId", { value: plan.backupPlanId });
    new cdk.CfnOutput(this, "BackupRoleArn", { value: backupRole.roleArn });
  }
}