import * as fs from "fs";
import * as path from "path";
import * as cdk from "aws-cdk-lib";
import * as ec2 from "aws-cdk-lib/aws-ec2";
import * as elbv2 from "aws-cdk-lib/aws-elasticloadbalancingv2";
import * as elbTargets from "aws-cdk-lib/aws-elasticloadbalancingv2-targets";
import * as logs from "aws-cdk-lib/aws-logs";
import * as route53 from "aws-cdk-lib/aws-route53";
import * as iam from "aws-cdk-lib/aws-iam";
import * as ssm from "aws-cdk-lib/aws-ssm";
import { Construct } from "constructs";
import { EnvName, prefix } from "../config";
import { bakedOpenSweArm64 } from "./ami-cache";

/**
 * Shared seahaven-vpc + internet-facing ALB facts (read-only recon 2026-06-26;
 * scratchpad/T12-infra-facts.md). A SINGLE VPC and a SINGLE shared ALB front
 * both the on-prem `seahaven-site` stack and open-swe. We IMPORT every one of
 * these and NEVER own them - open-swe only ADDS its own instance SG, a standalone
 * ALB-egress rule, listener rules, a target group, and DNS records.
 *
 * ── Cross-stack coordination on the SHARED listener + ALB SG (T13 review) ──
 * Two CDK stacks (seahaven-site, open-swe) add resources to the same imported
 * `:443` listener and ALB SG. This is safe because each stack owns ONLY the
 * resources it declares (its own logical ids): an on-prem `cdk deploy` computes a
 * changeset over its own template and cannot delete rules/egress it never
 * declared. The standalone-egress pattern is what on-prem itself uses
 * (sgr-0c57812752a3bca13), so it does not mutate the shared SG's own definition.
 *
 * The ONE shared namespace that REQUIRES coordination is listener-rule PRIORITY
 * (globally unique per listener; a collision is a fail-SAFE deploy error, not
 * silent drift). Ownership map - keep these disjoint when editing either stack:
 *   - seahaven-site (on-prem): priorities 4-7 + default.
 *   - open-swe:                priorities 2, 3 (webhooks) and 10, 11 (site).
 * open-swe's webhook rules are HOST-scoped to its own *.seahaven.com hosts, so
 * they never match (let alone "steal") any seahavenind.com / on-prem host.
 */
const SHARED = {
  vpcId: "vpc-0d3d4b67bd0cf8a68",
  availabilityZones: ["us-east-1a", "us-east-1b"],
  // Private subnets host the EC2 box. The single NAT gateway lives in 1a, so the
  // box is pinned to private1 (1a) for in-AZ NAT egress (no cross-AZ data $).
  privateSubnetIds: ["subnet-04e38c507e96f1926", "subnet-0a0b4fc6f296dfba5"],
  instanceSubnetId: "subnet-04e38c507e96f1926",
  instanceAz: "us-east-1a",
  albDnsName: "seahaven-com-1856441924.us-east-1.elb.amazonaws.com",
  albCanonicalHostedZoneId: "Z35SXDOTRQ7X7K",
  albSecurityGroupId: "sg-0b0301deed193258a",
  httpsListenerArn:
    "arn:aws:elasticloadbalancing:us-east-1:328440206208:listener/app/seahaven-com/222c3257354ab559/bab8bcf0da0e2927",
  publicZoneId: "Z06652411XKH89KTZD3XA",
  publicZoneName: "seahaven.com",
} as const;

/**
 * Per-env public hostnames, listener-rule priorities, and instance size.
 *
 * ── Listener-rule ordering hazard (load-bearing) ──
 * The shared listener already has a HOST-AGNOSTIC `/webhooks/*` PATH rule at
 * priority 5 (the on-prem seahaven-site stack owns it). ALB rules are first-match
 * by ASCENDING priority, so a `…/webhooks/*` request to our host would match
 * rule 5 (priority 5) and be forwarded to the on-prem target BEFORE any host rule
 * at 10+. Therefore our webhook rule MUST sit below priority 5. The catch-all
 * "site" rule (dashboard SPA + /dashboard/api/) carries no path that collides
 * with rule 5, so it can sit at any free higher number (10/11). Free priorities
 * confirmed by recon: 1-3 and 8+ (4=forgejo, 5=/webhooks/*, 6/7=seahavenind).
 */
const ENV_NET: Record<
  EnvName,
  {
    dashboardHost: string;
    hooksHost: string;
    webhookPriority: number;
    sitePriority: number;
    instanceType: string;
  }
> = {
  dev: {
    dashboardHost: "openswe-dev.seahaven.com",
    hooksHost: "hooks-dev.seahaven.com",
    webhookPriority: 2,
    sitePriority: 10,
    instanceType: "t4g.medium",
  },
  prod: {
    dashboardHost: "openswe.seahaven.com",
    hooksHost: "hooks.seahaven.com",
    webhookPriority: 3,
    sitePriority: 11,
    instanceType: "t4g.large",
  },
};

export interface AppServiceProps {
  readonly envName: EnvName;
  /** Least-privilege EC2 instance role (per-env; from InstanceRole). */
  readonly instanceRole: iam.IRole;
  /** S3 artifact key prefix the box pulls app.tar.gz / spa.tar.gz from. */
  readonly artifactPrefix?: string;
}

/**
 * The open-swe compute + ingress wiring for one env (T12):
 *  - one ARM64 EC2 box in private1 (1a), replacement-tolerant (no RETAIN volume),
 *  - a standalone instance SG reachable ONLY from the shared ALB SG on :80,
 *  - a target group -> instance:80 (nginx is the sole ingress; :2024 stays loopback),
 *  - two listener rules on the imported :443 listener (webhooks below the on-prem
 *    path rule; site catch-all above it), both -> the same TG,
 *  - Route53 alias records for both hostnames -> the shared ALB,
 *  - IaC-owned CloudWatch log groups at 30-day retention.
 *
 * Everything ALB/VPC/zone-side is IMPORTED. Synth is offline: the AMI is the
 * cdk.context.json-pinned AL2023 ARM64 placeholder until the baked
 * open-swe-base-arm64 id is pinned before the first real deploy.
 */
export class AppService extends Construct {
  public readonly instance: ec2.Instance;
  public readonly targetGroup: elbv2.ApplicationTargetGroup;
  /** Name of the SSM document CI fires to roll the box to the latest release. */
  public readonly deployDocumentName: string;

  constructor(scope: Construct, id: string, props: AppServiceProps) {
    super(scope, id);
    const env = props.envName;
    const p = prefix(env);
    const net = ENV_NET[env];
    const artifactPrefix = props.artifactPrefix ?? "releases/latest";

    // Import the shared VPC with explicit attributes (no fromLookup -> offline synth).
    const vpc = ec2.Vpc.fromVpcAttributes(this, "Vpc", {
      vpcId: SHARED.vpcId,
      availabilityZones: [...SHARED.availabilityZones],
      privateSubnetIds: [...SHARED.privateSubnetIds],
    });

    // Standalone instance SG. Egress open (NAT path); ingress only from the ALB SG.
    const instanceSg = new ec2.SecurityGroup(this, "InstanceSg", {
      vpc,
      securityGroupName: `${p}-instance-sg`,
      description: `${p} instance SG - ingress only from the shared ALB SG on :80; egress via NAT.`,
      allowAllOutbound: true,
    });
    instanceSg.addIngressRule(
      ec2.Peer.securityGroupId(SHARED.albSecurityGroupId),
      ec2.Port.tcp(80),
      `${p}: shared ALB SG to nginx :80`,
    );
    // Open the IMPORTED ALB SG to our instance via a STANDALONE egress rule, so we
    // never mutate the ALB SG's own (on-prem-owned) definition.
    new ec2.CfnSecurityGroupEgress(this, "AlbToInstanceEgress", {
      groupId: SHARED.albSecurityGroupId,
      ipProtocol: "tcp",
      fromPort: 80,
      toPort: 80,
      destinationSecurityGroupId: instanceSg.securityGroupId,
      description: `${p}: ALB to instance nginx :80`,
    });

    // The app-deploy procedure (deploy/ami/deploy.sh) is a normal reviewable repo
    // file; CDK base64-encodes it (single line - no `$`/regex-special chars in the
    // base64 alphabet) and renders it into user-data's @@DEPLOY_SH_B64@@ token, so
    // user-data writes it verbatim to /opt/open-swe/bin/deploy.sh at first boot.
    // The same file is run by the open-swe-<env>-deploy SSM document on every
    // release - a single source of truth for "pull release, build venv, restart".
    const deployShPath = path.join(__dirname, "..", "..", "..", "deploy", "ami", "deploy.sh");
    // Minify before embedding: strip full-line comments + blank lines (keep the
    // shebang) so the base64 fits EC2's 25.6 KB user-data limit. The repo file
    // keeps its comments; only the on-box copy is minified. deploy.sh becomes
    // opaque base64 here, so this never affects user-data's heredoc parsing.
    const deployShMin = fs
      .readFileSync(deployShPath, "utf8")
      .split("\n")
      .filter((line, i) => i === 0 || (!/^\s*#/.test(line) && line.trim() !== ""))
      .join("\n");
    const deployShB64 = Buffer.from(deployShMin, "utf8").toString("base64");

    // Render the provisioning script's @@tokens@@ into the instance user-data.
    // userDataCausesReplacement makes a bootstrap change roll a fresh box (the box
    // holds no durable state - see ami-cache.ts / user-data.sh). Editing deploy.sh
    // therefore also rolls the box (its base64 is embedded here) - acceptable: the
    // box is replacement-tolerant, and ongoing releases never touch user-data.
    const userDataPath = path.join(__dirname, "..", "..", "..", "deploy", "ami", "user-data.sh");
    const userData = ec2.UserData.custom(
      fs
        .readFileSync(userDataPath, "utf8")
        // %%...%% tokens are CDK-substituted here; they are DELIBERATELY a
        // different delimiter from the @@...@@ tokens user-data.sh seds into the
        // baked systemd/nginx templates, so CDK can never clobber a sed pattern
        // (a shared @@OPENSWE_ENV@@/@@SERVER_NAME@@ left the unit unsubstituted).
        .replace(/%%OPENSWE_ENV%%/g, env)
        .replace(/%%ASSETS_BUCKET%%/g, `${p}-assets`)
        .replace(/%%SERVER_NAME%%/g, net.dashboardHost)
        .replace(/%%ARTIFACT_PREFIX%%/g, artifactPrefix)
        .replace(/%%DEPLOY_SH_B64%%/g, deployShB64),
    );

    this.instance = new ec2.Instance(this, "Instance", {
      vpc,
      vpcSubnets: {
        subnets: [
          ec2.Subnet.fromSubnetAttributes(this, "InstanceSubnet", {
            subnetId: SHARED.instanceSubnetId,
            availabilityZone: SHARED.instanceAz,
          }),
        ],
      },
      instanceType: new ec2.InstanceType(net.instanceType),
      // The baked open-swe base AMI (deploy/ami packer build) - ARM64 Ubuntu 24.04
      // with the /opt/open-swe layout, openswe user, nginx, and CW agent that
      // user-data.sh assumes. Pinned by exact id (see ami-cache.ts); refresh by
      // rebuilding and updating BAKED_OPEN_SWE_AMI_ID.
      machineImage: bakedOpenSweArm64(),
      role: props.instanceRole,
      securityGroup: instanceSg,
      userData,
      userDataCausesReplacement: true,
      requireImdsv2: true,
      instanceName: `${p}-box`,
      blockDevices: [
        {
          deviceName: "/dev/xvda",
          // gp3 encrypted root; deleteOnTermination (no durable on-box state ->
          // intentionally NO standalone RETAIN volume; see ami-cache.ts).
          volume: ec2.BlockDeviceVolume.ebs(30, {
            volumeType: ec2.EbsDeviceVolumeType.GP3,
            encrypted: true,
            deleteOnTermination: true,
          }),
        },
      ],
    });

    // SSM deploy document (open-swe-<env>-deploy): runs the baked
    // /opt/open-swe/bin/deploy.sh to pull the latest release + restart. CI fires it
    // (tag-scoped to project=open-swe,env=<env>) after uploading a release, so the
    // app deploy role needs SendCommand ONLY on this document - NOT on the generic
    // AWS-RunShellScript (closes the T4 BLOCK#3 arbitrary-shell timebox).
    this.deployDocumentName = `${p}-deploy`;
    new ssm.CfnDocument(this, "DeployDoc", {
      name: this.deployDocumentName,
      documentType: "Command",
      documentFormat: "YAML",
      updateMethod: "NewVersion",
      content: {
        schemaVersion: "2.2",
        description: `Roll the ${p} box to the latest published release (runs /opt/open-swe/bin/deploy.sh).`,
        mainSteps: [
          {
            action: "aws:runShellScript",
            name: "deploy",
            inputs: {
              // Fixed command - no parameters, so nothing untrusted is interpolated
              // into the shell. The script itself reads /etc/open-swe/boot.env.
              runCommand: ["bash /opt/open-swe/bin/deploy.sh"],
            },
          },
        ],
      },
    });

    // Target group -> instance:80 (nginx). Health check hits nginx's /healthz
    // (returns 200; the dashboard TG health path defined in open-swe.nginx.conf).
    this.targetGroup = new elbv2.ApplicationTargetGroup(this, "Tg", {
      vpc,
      targetGroupName: `${p}-tg`,
      port: 80,
      protocol: elbv2.ApplicationProtocol.HTTP,
      targetType: elbv2.TargetType.INSTANCE,
      targets: [new elbTargets.InstanceTarget(this.instance)],
      deregistrationDelay: cdk.Duration.seconds(15),
      healthCheck: {
        path: "/healthz",
        healthyHttpCodes: "200",
        interval: cdk.Duration.seconds(30),
        timeout: cdk.Duration.seconds(5),
        healthyThresholdCount: 2,
        unhealthyThresholdCount: 3,
      },
    });

    // Import the shared :443 listener (with its ALB SG) and ADD our two rules.
    const albSg = ec2.SecurityGroup.fromSecurityGroupId(this, "AlbSg", SHARED.albSecurityGroupId, {
      mutable: false,
    });
    const listener = elbv2.ApplicationListener.fromApplicationListenerAttributes(this, "HttpsListener", {
      listenerArn: SHARED.httpsListenerArn,
      securityGroup: albSg,
    });

    // (1) Webhooks - accepted on EITHER host (integrations may target either), and
    // MUST be below the on-prem path-only rule 5 (see ENV_NET note).
    new elbv2.ApplicationListenerRule(this, "WebhooksRule", {
      listener,
      priority: net.webhookPriority,
      conditions: [
        elbv2.ListenerCondition.hostHeaders([net.dashboardHost, net.hooksHost]),
        elbv2.ListenerCondition.pathPatterns(["/webhooks/*"]),
      ],
      action: elbv2.ListenerAction.forward([this.targetGroup]),
    });
    // (2) Dashboard SPA + /dashboard/api/ (OAuth) - DASHBOARD host ONLY. The hooks
    // host intentionally serves nothing but /webhooks/* (rule 1), so the OAuth /
    // dashboard surface stays single-origin (OSWE-T12-02). Non-webhook paths on the
    // hooks host fall through to the on-prem default.
    new elbv2.ApplicationListenerRule(this, "SiteRule", {
      listener,
      priority: net.sitePriority,
      conditions: [elbv2.ListenerCondition.hostHeaders([net.dashboardHost])],
      action: elbv2.ListenerAction.forward([this.targetGroup]),
    });

    // Route53 ALIAS records -> the shared ALB, for both hostnames.
    const zone = route53.HostedZone.fromHostedZoneAttributes(this, "PublicZone", {
      hostedZoneId: SHARED.publicZoneId,
      zoneName: SHARED.publicZoneName,
    });
    const albAlias: route53.IAliasRecordTarget = {
      bind: () => ({
        dnsName: SHARED.albDnsName,
        hostedZoneId: SHARED.albCanonicalHostedZoneId,
      }),
    };
    for (const [label, host] of [
      ["Dashboard", net.dashboardHost],
      ["Hooks", net.hooksHost],
    ] as const) {
      new route53.ARecord(this, `${label}Alias`, {
        zone,
        recordName: host,
        target: route53.RecordTarget.fromAlias(albAlias),
        comment: `${p} ${label.toLowerCase()} -> shared seahaven-com ALB`,
      });
    }

    // IaC-owned CloudWatch log groups at 30-day retention. Names mirror the
    // CloudWatch-agent config (deploy/ami/templates/amazon-cloudwatch-agent.json);
    // owning them here makes retention declarative rather than agent-set. Logs are
    // not durable state -> DESTROY on stack delete.
    for (const suffix of ["app", "user-data", "nginx-access", "nginx-error"]) {
      new logs.LogGroup(this, `Log-${suffix}`, {
        logGroupName: `/open-swe/${env}/${suffix}`,
        retention: logs.RetentionDays.ONE_MONTH,
        removalPolicy: cdk.RemovalPolicy.DESTROY,
      });
    }
  }
}