AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31

Description: >
  miti99bot: Telegram bot on AWS Lambda (Go ZIP + LWA) with DynamoDB KV
  + EventBridge cron + SSM Parameter Store secrets. Strict free-tier deploy.

Parameters:
  StackEnv:
    Type: String
    Default: prod
    AllowedValues: [dev, prod]
    Description: Environment suffix used in SSM parameter paths.

  ModulesCSV:
    Type: String
    Default: util,misc,wordle,loldle,lolschedule,twentyq,trading
    Description: Comma-separated module names enabled at runtime (matches MODULES env).

  BotOwnerID:
    Type: String
    Default: ""
    Description: Telegram numeric user ID with bot-owner privileges. Empty disables Private/Protected commands.

  AdminUserIDs:
    Type: String
    Default: ""
    Description: Comma-separated Telegram user IDs allowed to use admin commands.

  # AWS Lambda Web Adapter ARM64 layer ARN. Pin a specific version so deploys
  # are reproducible. Bump by checking the latest at:
  #   https://github.com/awslabs/aws-lambda-web-adapter/releases
  LambdaAdapterLayerArn:
    Type: String
    Default: arn:aws:lambda:ap-southeast-1:753240598075:layer:LambdaAdapterLayerArm64:25
    Description: AWS Lambda Web Adapter layer ARN for the deploy region (ARM64).

  AlertEmail:
    Type: String
    Default: ""
    Description: Email for $1 budget alert. Leave empty to skip the budget resource.

Conditions:
  HasAlertEmail: !Not [!Equals [!Ref AlertEmail, ""]]

Globals:
  Function:
    Runtime: provided.al2023
    Architectures: [arm64]
    MemorySize: 256
    Timeout: 30
    Tracing: Active
    LoggingConfig:
      LogFormat: JSON
      ApplicationLogLevel: INFO
      SystemLogLevel: WARN

Resources:

  # --- Storage --------------------------------------------------------------

  BotTable:
    Type: AWS::DynamoDB::Table
    Properties:
      TableName: !Sub "${AWS::StackName}-data"
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions:
        - { AttributeName: pk, AttributeType: S }
        - { AttributeName: sk, AttributeType: S }
      KeySchema:
        - { AttributeName: pk, KeyType: HASH }
        - { AttributeName: sk, KeyType: RANGE }
      PointInTimeRecoverySpecification:
        PointInTimeRecoveryEnabled: false # paid feature; off for free tier
      Tags:
        - { Key: app, Value: miti99bot }
        - { Key: env, Value: !Ref StackEnv }

  # --- Compute --------------------------------------------------------------

  BotFunctionLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub "/aws/lambda/${AWS::StackName}"
      RetentionInDays: 7

  # Lambda emits a synthetic REPORT line at the end of every invocation.
  # On a cold start that line includes "Init Duration: <ms>". This filter
  # parses that field into a custom metric so the AWS-port plan's "P95 < 1.5s"
  # cold-start abort criterion is observable from day one.
  ColdStartMetricFilter:
    Type: AWS::Logs::MetricFilter
    Properties:
      LogGroupName: !Ref BotFunctionLogGroup
      FilterPattern: '[report="REPORT", reqid_label="RequestId:", reqid, dur_label="Duration:", dur, dur_unit="ms", bill_label="Billed", bill_dur_label, bill_dur, bill_unit, mem_label, mem_size_label, mem_size, mem_unit, max_label="Max", max_used_label="Memory", max_used_label2="Used:", max_used, max_used_unit, init_label="Init", init_dur_label="Duration:", init_dur, init_unit="ms"]'
      MetricTransformations:
        - MetricName: ColdStartInitDuration
          MetricNamespace: miti99bot
          MetricValue: $init_dur
          Unit: Milliseconds

  BotFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Ref AWS::StackName
      CodeUri: build/lambda/
      Handler: bootstrap
      Layers:
        - !Ref LambdaAdapterLayerArn
      LoggingConfig:
        LogGroup: !Ref BotFunctionLogGroup
      Environment:
        Variables:
          PORT: "8080"
          AWS_LAMBDA_EXEC_WRAPPER: /opt/bootstrap
          READINESS_CHECK_PATH: /
          # ---- App config (non-secret) ----
          KV_PROVIDER: dynamodb
          DYNAMODB_TABLE: !Ref BotTable
          MODULES: !Ref ModulesCSV
          BOT_OWNER_ID: !Ref BotOwnerID
          ADMIN_USER_IDS: !Ref AdminUserIDs
          # ---- Secrets (fetched from Parameter Store at Lambda cold start) ----
          TELEGRAM_BOT_TOKEN_PARAMETER_NAME: !Sub "/miti99bot/${StackEnv}/telegram-bot-token"
          TELEGRAM_WEBHOOK_SECRET_PARAMETER_NAME: !Sub "/miti99bot/${StackEnv}/telegram-webhook-secret"
          GEMINI_API_KEY_PARAMETER_NAME: !Sub "/miti99bot/${StackEnv}/gemini-api-key"
          CRON_SHARED_SECRET_PARAMETER_NAME: !Sub "/miti99bot/${StackEnv}/cron-shared-secret"
      FunctionUrlConfig:
        AuthType: NONE
        InvokeMode: BUFFERED
        Cors:
          AllowOrigins: ["*"] # Telegram doesn't send CORS; safe default
          AllowMethods: ["POST", "GET"]
          AllowHeaders: ["*"]
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref BotTable
        - Statement:
            - Effect: Allow
              Action:
                - ssm:GetParameter
                - ssm:GetParameters
              Resource: !Sub "arn:${AWS::Partition}:ssm:${AWS::Region}:${AWS::AccountId}:parameter/miti99bot/${StackEnv}/*"

  # --- Cron -----------------------------------------------------------------

  CronDLQ:
    Type: AWS::SQS::Queue
    Properties:
      QueueName: !Sub "${AWS::StackName}-cron-dlq"
      MessageRetentionPeriod: 1209600 # 14 days

  SchedulerExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal: { Service: scheduler.amazonaws.com }
            Action: sts:AssumeRole
      Policies:
        - PolicyName: cron-https-invoke
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              # HTTPS targets to Lambda Function URL — Scheduler treats them as
              # invocations of the function. Lock to this function's ARN only.
              - Effect: Allow
                Action: lambda:InvokeFunctionUrl
                Resource: !GetAtt BotFunction.Arn
              # DLQ
              - Effect: Allow
                Action: sqs:SendMessage
                Resource: !GetAtt CronDLQ.Arn

  # Concrete AWS::Scheduler::Schedule resources are added per cron handler;
  # the role + DLQ above are provisioned once and reused across all schedules.

  # --- Cost guard -----------------------------------------------------------

  MonthlyBudget:
    Type: AWS::Budgets::Budget
    Condition: HasAlertEmail
    Properties:
      Budget:
        BudgetName: !Sub "${AWS::StackName}-monthly"
        BudgetLimit: { Amount: '1', Unit: USD }
        TimeUnit: MONTHLY
        BudgetType: COST
      NotificationsWithSubscribers:
        - Notification:
            ComparisonOperator: GREATER_THAN
            NotificationType: ACTUAL
            Threshold: 80
            ThresholdType: PERCENTAGE
          Subscribers:
            - { Address: !Ref AlertEmail, SubscriptionType: EMAIL }
        - Notification:
            ComparisonOperator: GREATER_THAN
            NotificationType: ACTUAL
            Threshold: 100
            ThresholdType: PERCENTAGE
          Subscribers:
            - { Address: !Ref AlertEmail, SubscriptionType: EMAIL }

Outputs:
  FunctionUrl:
    Description: Public Function URL — set this as the Telegram webhook
    Value: !GetAtt BotFunctionUrl.FunctionUrl
  TableName:
    Description: DynamoDB table name (also exposed to the Lambda via DYNAMODB_TABLE)
    Value: !Ref BotTable
  LogGroup:
    Description: CloudWatch log group for the bot Lambda
    Value: !Ref BotFunctionLogGroup
  CronDLQArn:
    Description: ARN of the cron dead-letter queue
    Value: !GetAtt CronDLQ.Arn