locals {
  alarm_functions = {
    unlock = {
      function_name = aws_lambda_function.unlock.function_name
      description   = "door-unlock-api-unlock Lambda is erroring — physical door unlock calls may be failing"
    }
    lockdown = {
      function_name = aws_lambda_function.lockdown.function_name
      description   = "door-unlock-api-lockdown Lambda is erroring — lockdown commands may not be executing"
    }
    authorizer = {
      function_name = aws_lambda_function.authorizer.function_name
      description   = "door-unlock-api-authorizer Lambda is erroring — all API requests will be rejected"
    }
    poller = {
      function_name = aws_lambda_function.poller.function_name
      description   = "door-unlock-api-lockdown-poller Lambda is erroring — lockdown state polling may be broken"
    }
    blf_sync = {
      function_name = aws_lambda_function.blf_sync.function_name
      description   = "door-unlock-api-blf-sync Lambda is erroring — department BLF updates may not be applying"
    }
  }
}

resource "aws_cloudwatch_metric_alarm" "lambda_errors" {
  for_each = local.alarm_functions

  alarm_name          = "${each.value.function_name}-errors"
  alarm_description   = each.value.description
  namespace           = "AWS/Lambda"
  metric_name         = "Errors"
  statistic           = "Sum"
  period              = 300
  evaluation_periods  = 1
  threshold           = 0
  comparison_operator = "GreaterThanThreshold"
  treat_missing_data  = "notBreaching"
  alarm_actions       = [data.aws_sns_topic.site_alerts.arn]

  dimensions = {
    FunctionName = each.value.function_name
  }
}