# AWS Region
variable "aws_region" {
  description = "Region in which AWS Resources to be created"
  type = string
  default = "us-east-1"  
}

# AWS EC2 Instance Type
variable "instance_type" {
  description = "EC2 Instance Type"
  type = string
  default = "t3.micro"  
}

# AWS EC2 Instance Key Pair
variable "instance_keypair" {
  description = "AWS EC2 Key pair that need to be associated with EC2 Instance"
  type = string
  default = "terraform-key"
}

# c1-versions.tf
region  = var.aws_region

# c5-ec2instance.tf
instance_type = var.instance_type
key_name = var.instance_keypair  

# Create Security Group - SSH Traffic
resource "aws_security_group" "vpc-ssh" {
  name        = "vpc-ssh"
  description = "Dev VPC SSH"
  ingress {
    description = "Allow Port 22"
    from_port   = 22
    to_port     = 22
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }
  egress {
    description = "Allow all ip and ports outboun"
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

# Create Security Group - Web Traffic
resource "aws_security_group" "vpc-web" {
  name        = "vpc-web"
  description = "Dev VPC web"
  ingress {
    description = "Allow Port 80"
    from_port   = 80
    to_port     = 80
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  ingress {
    description = "Allow Port 443"
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
  }

  egress {
    description = "Allow all ip and ports outbound"
    from_port   = 0
    to_port     = 0
    protocol    = "-1"
    cidr_blocks = ["0.0.0.0/0"]
  }
}

# List Item
vpc_security_group_ids = [aws_security_group.vpc-ssh.id, aws_security_group.vpc-web.id]  

# Get latest AMI ID for Amazon Linux2 OS
# Get Latest AWS AMI ID for Amazon2 Linux
data "aws_ami" "amzlinux2" {
  most_recent = true
  owners = [ "amazon" ]
  filter {
    name = "name"
    values = [ "amzn2-ami-hvm-*-gp2" ]
  }
  filter {
    name = "root-device-type"
    values = [ "ebs" ]
  }
  filter {
    name = "virtualization-type"
    values = [ "hvm" ]
  }
  filter {
    name = "architecture"
    values = [ "x86_64" ]
  }
}

# Reference Datasource to get the latest AMI ID
ami = data.aws_ami.amzlinux2.id 

# EC2 Instance
resource "aws_instance" "myec2vm" {
  ami = data.aws_ami.amzlinux2.id 
  instance_type = var.instance_type
  user_data = file("${path.module}/app1-install.sh")
  key_name = var.instance_keypair
  vpc_security_group_ids = [aws_security_group.vpc-ssh.id, aws_security_group.vpc-web.id]  
  tags = {
    "Name" = "EC2 Demo 2"
  }
}

# Terraform Output Values
output "instance_publicip" {
  description = "EC2 Instance Public IP"
  value = aws_instance.myec2vm.public_ip
}

output "instance_publicdns" {
  description = "EC2 Instance Public DNS"
  value = aws_instance.myec2vm.public_dns
}

# Terraform Initialize
terraform init
Observation:
1) Initialized Local Backend
2) Downloaded the provider plugins (initialized plugins)
3) Review the folder structure ".terraform folder"

# Terraform Validate
terraform validate
Observation:
1) If any changes to files, those will come as printed in stdout (those file names will be printed in CLI)

# Terraform Plan
terraform plan
Observation:
1) Verify the latest AMI ID picked and displayed in plan
2) Verify the number of resources that going to get created
3) Verify the variable replacements worked as expected

# Terraform Apply
terraform apply 
[or]
terraform apply -auto-approve
Observations:
1) Create resources on cloud
2) Created terraform.tfstate file when you run the terraform apply command
3) Verify the EC2 Instance AMI ID which got created

# Access index.html
http://<PUBLIC-IP>/index.html
http://<PUBLIC-IP>/app1/index.html

# Access metadata.html
http://<PUBLIC-IP>/app1/metadata.html

# Terraform Destroy
terraform plan -destroy  # You can view destroy plan using this command
terraform destroy

# Clean-Up Files
rm -rf .terraform*
rm -rf terraform.tfstate*