# Example Terraform Configuration for AWS Web Application
# This example creates a simple web application infrastructure

terraform {
  required_version = ">= 1.6.0"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 5.0"
    }
  }
}

provider "aws" {
  region = var.aws_region
}

# VPC Module
module "vpc" {
  source = "../../modules/vpc"

  name_prefix          = var.name_prefix
  vpc_cidr             = "10.0.0.0/16"
  availability_zones   = ["us-east-1a", "us-east-1b", "us-east-1c"]
  public_subnet_cidrs  = ["10.0.1.0/24", "10.0.2.0/24", "10.0.3.0/24"]
  private_subnet_cidrs = ["10.0.11.0/24", "10.0.12.0/24", "10.0.13.0/24"]

  enable_nat_gateway = true
  single_nat_gateway = false  # One NAT per AZ for HA

  tags = local.common_tags
}

# Security Groups
resource "aws_security_group" "alb" {
  name        = "${var.name_prefix}-alb-sg"
  description = "Security group for Application Load Balancer"
  vpc_id      = module.vpc.vpc_id

  ingress {
    from_port   = 443
    to_port     = 443
    protocol    = "tcp"
    cidr_blocks = ["0.0.0.0/0"]
    description = "HTTPS from internet"
  }

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

  tags = merge(
    local.common_tags,
    { Name = "${var.name_prefix}-alb-sg" }
  )
}

# Application Load Balancer
resource "aws_lb" "main" {
  name               = "${var.name_prefix}-alb"
  internal           = false
  load_balancer_type = "application"
  security_groups    = [aws_security_group.alb.id]
  subnets            = module.vpc.public_subnet_ids

  enable_deletion_protection = var.environment == "prod"

  tags = merge(
    local.common_tags,
    { Name = "${var.name_prefix}-alb" }
  )
}

# Common tags
locals {
  common_tags = {
    Environment = var.environment
    Project     = var.project_name
    ManagedBy   = "Terraform"
    Owner       = var.owner
  }
}

# Variables
variable "aws_region" {
  description = "AWS region"
  type        = string
  default     = "us-east-1"
}

variable "name_prefix" {
  description = "Prefix for resource names"
  type        = string
}

variable "environment" {
  description = "Environment name"
  type        = string
}

variable "project_name" {
  description = "Project name"
  type        = string
}

variable "owner" {
  description = "Owner email"
  type        = string
}

# Outputs
output "vpc_id" {
  description = "VPC ID"
  value       = module.vpc.vpc_id
}

output "alb_dns_name" {
  description = "ALB DNS name"
  value       = aws_lb.main.dns_name
}