# Terraform Configuration: Docker Service Deployment
# ===================================================
# This configuration manages Docker containers on localhost.
# Designed for Tier 1+ agents to deploy services.
#
# For Tier 0 agents: Plan only (terraform plan)
#
# Usage:
#   terraform init
#   terraform plan -var="service_name=myapp" -var="image=nginx:alpine"
#   terraform apply  # Tier 1+ only

terraform {
  required_providers {
    docker = {
      source  = "kreuzwerker/docker"
      version = "~> 3.0"
    }
  }
}

provider "docker" {
  host = "unix:///var/run/docker.sock"
}

# Variables
variable "service_name" {
  description = "Name of the service/container"
  type        = string
  default     = "tf-managed-service"
}

variable "image" {
  description = "Docker image to deploy"
  type        = string
  default     = "nginx:alpine"
}

variable "internal_port" {
  description = "Container internal port"
  type        = number
  default     = 80
}

variable "external_port" {
  description = "Host external port"
  type        = number
  default     = 8090
}

variable "network_name" {
  description = "Docker network to attach"
  type        = string
  default     = "spark-net"
}

variable "environment" {
  description = "Environment variables for the container"
  type        = map(string)
  default     = {}
}

variable "labels" {
  description = "Labels to apply to the container"
  type        = map(string)
  default = {
    "managed-by" = "terraform"
    "agent-tier" = "1"
  }
}

# Data source to reference existing network
data "docker_network" "main" {
  name = var.network_name
}

# Pull the image
resource "docker_image" "service" {
  name         = var.image
  keep_locally = true
}

# Create the container
resource "docker_container" "service" {
  name  = var.service_name
  image = docker_image.service.image_id

  ports {
    internal = var.internal_port
    external = var.external_port
  }

  networks_advanced {
    name = data.docker_network.main.name
  }

  restart = "unless-stopped"

  dynamic "env" {
    for_each = var.environment
    content {
      key   = env.key
      value = env.value
    }
  }

  labels {
    label = "managed-by"
    value = "terraform"
  }

  labels {
    label = "service-name"
    value = var.service_name
  }

  # Health check
  healthcheck {
    test         = ["CMD", "wget", "-q", "--spider", "http://localhost:${var.internal_port}/"]
    interval     = "30s"
    timeout      = "10s"
    retries      = 3
    start_period = "10s"
  }

  lifecycle {
    create_before_destroy = true
  }
}

# Outputs
output "container_id" {
  description = "The ID of the deployed container"
  value       = docker_container.service.id
}

output "container_name" {
  description = "The name of the deployed container"
  value       = docker_container.service.name
}

output "service_url" {
  description = "URL to access the service"
  value       = "http://localhost:${var.external_port}"
}

output "network" {
  description = "Network the container is attached to"
  value       = var.network_name
}