locals {
  az = ["(az1)", "(az2)"]
}

resource "aws_vpc" "main" {
  cidr_block           = "10.0.0.0/16"
  enable_dns_hostnames = true # パブリックIPアドレスを持つインスタンスにDNSホスト名を付与する
  enable_dns_support   = true # VPC内のインスタンスにDNSサーバーを使用する

  tags = {
    Name = "main"
  }
}

resource "aws_internet_gateway" "main" {
  vpc_id = aws_vpc.main.id

  tags = {
    Name = "main"
  }
}

resource "aws_subnet" "publics" {
  count             = 2
  vpc_id            = aws_vpc.main.id
  cidr_block        = cidrsubnet(aws_vpc.main.cidr_block, 8, count.index)
  availability_zone = local.az[count.index]

  tags = {
    Name = "public-${local.az[count.index]}"
  }
}

resource "aws_subnet" "privates" {
  count             = 2
  vpc_id            = aws_vpc.main.id
  cidr_block        = cidrsubnet(aws_vpc.main.cidr_block, 8, count.index + 2)
  availability_zone = local.az[count.index]

  tags = {
    Name = "private-${local.az[count.index]}"
  }
}

resource "aws_route_table" "public" {
  vpc_id = aws_vpc.main.id

  route {
    cidr_block = "0.0.0.0/0"
    gateway_id = aws_internet_gateway.main.id
  }
}

resource "aws_route_table_association" "public" {
  count          = 2
  subnet_id      = aws_subnet.publics[count.index].id
  route_table_id = aws_route_table.public.id
}

resource "aws_route_table" "private" {
  vpc_id = aws_vpc.main.id
}

# s3へのvpceはGateway型なので、route tableに追加する必要がある
resource "aws_vpc_endpoint" "s3" {
  vpc_id          = aws_vpc.main.id
  service_name    = "com.amazonaws.(region).s3"
  route_table_ids = [aws_route_table.private.id]

  tags = {
    Name = "s3_vpce"
  }
}

resource "aws_route_table_association" "private" {
  count          = 2
  subnet_id      = aws_subnet.privates[count.index].id
  route_table_id = aws_route_table.private.id
}

resource "aws_security_group" "vpce" {
  name        = "vpce"
  description = "vpce"
  vpc_id      = aws_vpc.main.id

  # HTTPSのみ許可すればいい
  ingress {
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = [aws_vpc.main.cidr_block] # vpc内からのみアクセス可能
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_vpc_endpoint" "ecr_dkr" {
  vpc_id              = aws_vpc.main.id
  service_name        = "com.amazonaws.(region).ecr.dkr"
  vpc_endpoint_type   = "Interface"
  private_dns_enabled = true
  subnet_ids          = aws_subnet.privates[*].id
  security_group_ids  = [aws_security_group.vpce.id]

  tags = {
    Name = "ecr_dkr_vpce"
  }
}

resource "aws_vpc_endpoint" "ecr_api" {
  vpc_id              = aws_vpc.main.id
  service_name        = "com.amazonaws.(region).ecr.api"
  vpc_endpoint_type   = "Interface"
  private_dns_enabled = true
  subnet_ids          = aws_subnet.privates[*].id
  security_group_ids  = [aws_security_group.vpce.id]

  tags = {
    Name = "ecr_api_vpce"
  }
}

resource "aws_vpc_endpoint" "cloudwatch_logs" {
  vpc_id              = aws_vpc.main.id
  service_name        = "com.amazonaws.(region).logs"
  vpc_endpoint_type   = "Interface"
  private_dns_enabled = true
  subnet_ids          = aws_subnet.privates[*].id
  security_group_ids  = [aws_security_group.vpce.id]

  tags = {
    Name = "cloudwatch_logs_vpce"
  }
}

resource "aws_vpc_endpoint" "ssmmessages" {
  vpc_id              = aws_vpc.main.id
  service_name        = "com.amazonaws.(region).ssmmessages"
  vpc_endpoint_type   = "Interface"
  private_dns_enabled = true
  subnet_ids          = aws_subnet.privates[*].id
  security_group_ids  = [aws_security_group.vpce.id]

  tags = {
    Name = "ssmmessages_vpce"
  }
}

resource "aws_vpc_endpoint" "ssm" {
  vpc_id              = aws_vpc.main.id
  service_name        = "com.amazonaws.(region).ssm"
  vpc_endpoint_type   = "Interface"
  private_dns_enabled = true
  subnet_ids          = aws_subnet.privates[*].id
  security_group_ids  = [aws_security_group.vpce.id]

  tags = {
    Name = "ssm_vpce"
  }
}

resource "aws_lb" "main" {
  name               = "main"
  internal           = false
  subnets            = var.public_subnet_ids
  security_groups    = [aws_security_group.alb.id]
  load_balancer_type = "application"

  tags = {
    Name = "main"
  }
}

resource "aws_security_group" "alb" {
  name        = "alb"
  description = "alb"
  vpc_id      = var.vpc_id

  ingress {
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_lb_listener" "main" {
  load_balancer_arn = aws_lb.main.arn
  port              = 80
  protocol          = "HTTP"

  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.main.arn
  }
}

resource "aws_lb_target_group" "main" {
  name        = "main"
  port        = 80
  protocol    = "HTTP"
  vpc_id      = var.vpc_id
  target_type = "ip"

  health_check {
    path = "/"
  }
}

resource "aws_iam_role" "nginx_task_role" {
  name = "nginx_ecs_task_role"
  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Principal = {
          Service = "ecs-tasks.amazonaws.com"
        }
      }
    ]
  })

  # ECS TaskがSSMを使えるようにすることでECS Execできるようにする
  inline_policy {
    name = "ecs_exec"
    policy = jsonencode({
      Version = "2012-10-17"
      Statement = [
        {
          Action = [
            "ssmmessages:CreateControlChannel",
            "ssmmessages:CreateDataChannel",
            "ssmmessages:OpenControlChannel",
            "ssmmessages:OpenDataChannel"
          ]
          Effect   = "Allow"
          Resource = "*"
        }
      ]
    })
  }
}

# ECSコンテナエージェントが使うIAMロール
# ECSコンテナエージェントの役割は、ECRなどからのイメージのpullや、CloudWatch Logsへのログの書き込みなど
resource "aws_iam_role" "nginx_execution_role" {
  name = "nginx_ecs_execution_role"
  assume_role_policy = jsonencode({
    Version = "2012-10-17"
    Statement = [
      {
        Action = "sts:AssumeRole"
        Effect = "Allow"
        Principal = {
          Service = "ecs-tasks.amazonaws.com"
        }
      }
    ]
  })

  managed_policy_arns = [
    "arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy"
  ]
}



resource "aws_ecs_cluster" "main" {
  name = "main"
}

resource "aws_ecs_task_definition" "nginx" {
  family                   = "main"
  network_mode             = "awsvpc"
  requires_compatibilities = ["FARGATE"]
  cpu                      = "256"
  memory                   = "512"
  task_role_arn            = aws_iam_role.nginx_task_role.arn
  execution_role_arn       = aws_iam_role.nginx_execution_role.arn

  container_definitions = jsonencode(
    [
      {
        "name" : "nginx",
        "image" : "(ecrのuri)",
        "essentials" : true,
        "logConfiguration" : {
          "logDriver" : "awslogs",
          "options" : {
            "awslogs-group" : aws_cloudwatch_log_group.ecs.name,
            "awslogs-region" : "(region)",
            "awslogs-stream-prefix" : "ecs"
          }
        },
        "portMappings" : [
          {
            "containerPort" : 80,
            "hostPort" : 80,
            "protocol" : "tcp"
          }
        ],
      }
    ]
  )
}

resource "aws_security_group" "ecs" {
  name        = "ecs"
  description = "ecs"
  vpc_id      = var.vpc_id

  ingress {
    from_port       = 80
    to_port         = 80
    protocol        = "tcp"
    security_groups = [var.aws_lb_security_group_id]
  }

  egress {
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

resource "aws_ecs_service" "main" {
  name                   = "main"
  cluster                = aws_ecs_cluster.main.id
  task_definition        = aws_ecs_task_definition.nginx.arn
  desired_count          = 1
  launch_type            = "FARGATE"
  enable_execute_command = true # ECS Execを有効化

  deployment_controller {
    type = "CODE_DEPLOY"
  }

  network_configuration {
    assign_public_ip = false
    subnets          = var.private_subnet_ids
    security_groups  = [aws_security_group.ecs.id]
  }

  load_balancer {
    target_group_arn = var.aws_lb_target_group_arn
    container_name   = "nginx"
    container_port   = 80
  }

}

resource "aws_cloudwatch_log_group" "ecs" {
  name              = "/ecs/main"
  retention_in_days = 7
}