resource "aws_iam_role" "lambda_role" {
  name = "${var.project_name}-lambda-role"

  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Principal = {
          Service = "lambda.amazonaws.com"
        }
      }
    ]
  })

  tags = {
    Name = "${var.project_name}-lambda-role"
  }
}

# Basic Lambda execution permissions
resource "aws_iam_role_policy_attachment" "lambda_basic" {
  role       = aws_iam_role.lambda_role.name
  policy_arn = "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
}

# DynamoDB permissions
resource "aws_iam_role_policy" "lambda_dynamodb" {
  name = "${var.project_name}-dynamodb-policy"
  role = aws_iam_role.lambda_role.id

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Effect = "Allow"
        Action = [
          "dynamodb:GetItem",
          "dynamodb:PutItem",
          "dynamodb:UpdateItem",
          "dynamodb:DeleteItem",
          "dynamodb:Query",
          "dynamodb:Scan",
          "dynamodb:BatchGetItem",
          "dynamodb:BatchWriteItem"
        ]
        Resource = [
          aws_dynamodb_table.users.arn,
          aws_dynamodb_table.conversations.arn,
          "${aws_dynamodb_table.users.arn}/index/*",
          "${aws_dynamodb_table.conversations.arn}/index/*"
        ]
      }
    ]
  })
}

# Secrets Manager permissions
resource "aws_iam_role_policy" "lambda_secrets" {
  name = "${var.project_name}-secrets-policy"
  role = aws_iam_role.lambda_role.id

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Effect = "Allow"
        Action = [
          "secretsmanager:GetSecretValue",
          "secretsmanager:DescribeSecret"
        ]
        Resource = [
          aws_secretsmanager_secret.discord_bot_token.arn,
          aws_secretsmanager_secret.discord_public_key.arn,
          aws_secretsmanager_secret.github_token.arn,
          aws_secretsmanager_secret.openai_api_key.arn
        ]
      }
    ]
  })
}

# CloudWatch Logs permissions
resource "aws_iam_role_policy" "lambda_logs" {
  name = "${var.project_name}-logs-policy"
  role = aws_iam_role.lambda_role.id

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Effect = "Allow"
        Action = [
          "logs:CreateLogGroup",
          "logs:CreateLogStream",
          "logs:PutLogEvents"
        ]
        Resource = "arn:aws:logs:${var.aws_region}:*:log-group:/aws/lambda/${var.project_name}*"
      }
    ]
  })
}

# ECR permissions for pulling Lambda image
resource "aws_iam_role_policy" "lambda_ecr" {
  name = "${var.project_name}-ecr-policy"
  role = aws_iam_role.lambda_role.id

  policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Effect = "Allow"
        Action = [
          "ecr:GetDownloadUrlForLayer",
          "ecr:BatchGetImage",
          "ecr:BatchCheckLayerAvailability"
        ]
        Resource = "${data.aws_ecr_repository.lambda.arn}"
      },
      {
        Effect = "Allow"
        Action = [
          "ecr:GetAuthorizationToken"
        ]
        Resource = "*"
      }
    ]
  })
}