import { Construct } from 'constructs';
import * as cdk from 'aws-cdk-lib';
import * as dynamodb from 'aws-cdk-lib/aws-dynamodb';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import * as events from 'aws-cdk-lib/aws-events';
import * as targets from 'aws-cdk-lib/aws-events-targets';
import * as scheduler from 'aws-cdk-lib/aws-scheduler';
import * as iam from 'aws-cdk-lib/aws-iam';
import * as logs from 'aws-cdk-lib/aws-logs';
import { PythonFunction } from '@aws-cdk/aws-lambda-python-alpha';
import * as path from 'path';

export class EmailPipelineConstruct extends Construct {
  public readonly table: dynamodb.Table;
  public readonly conversationFn: lambda.IFunction;

  constructor(scope: Construct, id: string) {
    super(scope, id);

    const account = cdk.Stack.of(this).account;
    const region = cdk.Stack.of(this).region;

    // ── DynamoDB ──────────────────────────────────────────────

    this.table = new dynamodb.Table(this, 'Table', {
      tableName: 'exec-aide',
      billingMode: dynamodb.BillingMode.PAY_PER_REQUEST,
      partitionKey: { name: 'pk', type: dynamodb.AttributeType.STRING },
      sortKey: { name: 'sk', type: dynamodb.AttributeType.STRING },
      timeToLiveAttribute: 'ttl',
      removalPolicy: cdk.RemovalPolicy.RETAIN,
    });

    this.table.addGlobalSecondaryIndex({
      indexName: 'by-date',
      partitionKey: { name: 'classified_date', type: dynamodb.AttributeType.STRING },
      sortKey: { name: 'sk', type: dynamodb.AttributeType.STRING },
      projectionType: dynamodb.ProjectionType.ALL,
    });

    // ── Shared environment + IAM ──────────────────────────────

    const lambdaEnv = {
      TABLE_NAME: this.table.tableName,
      SECRET_GMAIL: 'exec-aide/gmail-oauth',
      SECRET_SLACK: 'exec-aide/slack-credentials',
      SSM_PREFIX: '/exec-aide',
    };

    const secretsReadPolicy = new iam.PolicyStatement({
      actions: ['secretsmanager:GetSecretValue'],
      resources: [
        `arn:aws:secretsmanager:${region}:${account}:secret:exec-aide/gmail-oauth-*`,
        `arn:aws:secretsmanager:${region}:${account}:secret:exec-aide/slack-credentials-*`,
      ],
    });

    const secretsWritePolicy = new iam.PolicyStatement({
      actions: ['secretsmanager:PutSecretValue'],
      resources: [
        `arn:aws:secretsmanager:${region}:${account}:secret:exec-aide/gmail-oauth-*`,
      ],
    });

    const ssmPolicy = new iam.PolicyStatement({
      actions: ['ssm:GetParametersByPath', 'ssm:GetParameter'],
      resources: [
        `arn:aws:ssm:${region}:${account}:parameter/exec-aide`,
        `arn:aws:ssm:${region}:${account}:parameter/exec-aide/*`,
      ],
    });

    // ── Fetch & Classify Lambda ───────────────────────────────

    const fetchClassify = new PythonFunction(this, 'FetchClassify', {
      functionName: 'exec-aide-fetch-classify',
      entry: path.join(__dirname, '../../src'),
      index: 'fetch_classify/app.py',
      handler: 'lambda_handler',
      runtime: lambda.Runtime.PYTHON_3_12,
      architecture: lambda.Architecture.ARM_64,
      memorySize: 256,
      timeout: cdk.Duration.seconds(120),
      environment: lambdaEnv,
      logRetention: logs.RetentionDays.TWO_MONTHS,
    });

    this.table.grantReadWriteData(fetchClassify);
    fetchClassify.addToRolePolicy(secretsReadPolicy);
    fetchClassify.addToRolePolicy(secretsWritePolicy);
    fetchClassify.addToRolePolicy(ssmPolicy);
    fetchClassify.addToRolePolicy(new iam.PolicyStatement({
      actions: ['bedrock:InvokeModel'],
      resources: [
        'arn:aws:bedrock:*::foundation-model/anthropic.*',
        `arn:aws:bedrock:${region}:${account}:inference-profile/us.anthropic.*`,
      ],
    }));

    new events.Rule(this, 'PollSchedule', {
      ruleName: 'exec-aide-fetch-classify-poll',
      description: 'Poll Gmail for new messages',
      schedule: events.Schedule.rate(cdk.Duration.minutes(15)),
      targets: [new targets.LambdaFunction(fetchClassify)],
    });

    // ── Daily Digest Lambda ───────────────────────────────────

    const dailyDigest = new PythonFunction(this, 'DailyDigest', {
      functionName: 'exec-aide-daily-digest',
      entry: path.join(__dirname, '../../src'),
      index: 'daily_digest/app.py',
      handler: 'lambda_handler',
      runtime: lambda.Runtime.PYTHON_3_12,
      architecture: lambda.Architecture.ARM_64,
      memorySize: 256,
      timeout: cdk.Duration.seconds(120),
      environment: lambdaEnv,
      logRetention: logs.RetentionDays.TWO_MONTHS,
    });

    this.table.grantReadWriteData(dailyDigest);
    dailyDigest.addToRolePolicy(secretsReadPolicy);
    dailyDigest.addToRolePolicy(secretsWritePolicy);
    dailyDigest.addToRolePolicy(ssmPolicy);

    // ── EventBridge Scheduler (DST-aware 5 PM ET) ─────────────

    const schedulerRole = new iam.Role(this, 'DigestSchedulerRole', {
      roleName: 'exec-aide-digest-scheduler',
      assumedBy: new iam.ServicePrincipal('scheduler.amazonaws.com'),
    });
    dailyDigest.grantInvoke(schedulerRole);

    const schedule = new scheduler.CfnSchedule(this, 'DigestSchedule', {
      name: 'exec-aide-daily-digest',
      description: 'Daily 5 PM ET inbox digest',
      scheduleExpression: 'cron(0 17 ? * MON-FRI *)',
      scheduleExpressionTimezone: 'America/New_York',
      flexibleTimeWindow: { mode: 'OFF' },
      state: 'ENABLED',
      target: {
        arn: dailyDigest.functionArn,
        roleArn: schedulerRole.roleArn,
      },
    });

    dailyDigest.addPermission('SchedulerInvoke', {
      principal: new iam.ServicePrincipal('scheduler.amazonaws.com'),
      sourceArn: `arn:aws:scheduler:${region}:${account}:schedule/default/${schedule.name}`,
    });

    // ── Conversation Lambda ───────────────────────────────────

    const conversation = new PythonFunction(this, 'Conversation', {
      functionName: 'exec-aide-conversation',
      entry: path.join(__dirname, '../../src'),
      index: 'conversation/app.py',
      handler: 'lambda_handler',
      runtime: lambda.Runtime.PYTHON_3_12,
      architecture: lambda.Architecture.ARM_64,
      memorySize: 512,
      timeout: cdk.Duration.seconds(180),
      environment: lambdaEnv,
      logRetention: logs.RetentionDays.TWO_MONTHS,
    });

    this.table.grantReadWriteData(conversation);
    conversation.addToRolePolicy(secretsReadPolicy);
    conversation.addToRolePolicy(secretsWritePolicy);
    conversation.addToRolePolicy(ssmPolicy);
    conversation.addToRolePolicy(new iam.PolicyStatement({
      actions: ['bedrock:InvokeModel'],
      resources: [
        'arn:aws:bedrock:*::foundation-model/anthropic.*',
        `arn:aws:bedrock:${region}:${account}:inference-profile/us.anthropic.*`,
      ],
    }));
    dailyDigest.grantInvoke(conversation);

    this.conversationFn = conversation;
  }
}