# ============================================================
# Step Functions State Machine
# ============================================================
resource "aws_iam_role" "sfn" {
  name = "${local.prefix}-sfn-role"
  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [{
      Action = "sts:AssumeRole"
      Effect = "Allow"
      Principal = { Service = "states.amazonaws.com" }
    }]
  })
}

resource "aws_iam_role_policy" "sfn" {
  name = "${local.prefix}-sfn-policy"
  role = aws_iam_role.sfn.id
  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [{
      Effect   = "Allow"
      Action   = "lambda:InvokeFunction"
      Resource = [
        aws_lambda_function.download.arn,
        aws_lambda_function.transcribe.arn,
        aws_lambda_function.check.arn,
        aws_lambda_function.summarize.arn,
        aws_lambda_function.notify.arn,
      ]
    }]
  })
}

resource "aws_sfn_state_machine" "pipeline" {
  name     = "${local.prefix}-pipeline"
  role_arn = aws_iam_role.sfn.arn

  definition = jsonencode({
    Comment = "SP Stream Transcribe Pipeline"
    StartAt = "Download"
    States = {
      Download = {
        Type     = "Task"
        Resource = aws_lambda_function.download.arn
        Next     = "StartTranscribe"
        Retry    = [{ ErrorEquals = ["States.ALL"], MaxAttempts = 2, IntervalSeconds = 10 }]
        Catch    = [{ ErrorEquals = ["States.ALL"], Next = "NotifyError", ResultPath = "$.error_info" }]
      }
      StartTranscribe = {
        Type     = "Task"
        Resource = aws_lambda_function.transcribe.arn
        Next     = "WaitForTranscribe"
        Catch    = [{ ErrorEquals = ["States.ALL"], Next = "NotifyError", ResultPath = "$.error_info" }]
      }
      WaitForTranscribe = {
        Type    = "Wait"
        Seconds = 30
        Next    = "CheckTranscribe"
      }
      CheckTranscribe = {
        Type     = "Task"
        Resource = aws_lambda_function.check.arn
        Next     = "IsTranscribeComplete"
        Catch    = [{ ErrorEquals = ["States.ALL"], Next = "NotifyError", ResultPath = "$.error_info" }]
      }
      IsTranscribeComplete = {
        Type = "Choice"
        Choices = [{
          Variable     = "$.transcribe_status"
          StringEquals = "COMPLETED"
          Next         = "Summarize"
        }, {
          Variable     = "$.transcribe_status"
          StringEquals = "FAILED"
          Next         = "NotifyError"
        }]
        Default = "WaitForTranscribe"
      }
      Summarize = {
        Type     = "Task"
        Resource = aws_lambda_function.summarize.arn
        Next     = "Notify"
        Retry    = [{ ErrorEquals = ["States.ALL"], MaxAttempts = 3, IntervalSeconds = 30, BackoffRate = 2 }]
        Catch    = [{ ErrorEquals = ["States.ALL"], Next = "NotifyError", ResultPath = "$.error_info" }]
      }
      Notify = {
        Type     = "Task"
        Resource = aws_lambda_function.notify.arn
        End      = true
      }
      NotifyError = {
        Type     = "Task"
        Resource = aws_lambda_function.notify.arn
        End      = true
      }
    }
  })
}