#!/bin/bash

# Continuous Deployment Script for Kubernetes
# This script deploys your application to a Kubernetes cluster

# =============================================================================
# Environment Variables (with default values)
# =============================================================================

# Kubernetes Configuration
KUBECONFIG_DATA="${KUBECONFIG_DATA:-}"
KUBERNETES_URL="${KUBERNETES_URL:-https://kubernetes.default.svc}"
KUBERNETES_NAMESPACE="${KUBERNETES_NAMESPACE:-default}"
KUBERNETES_INGRESS_HOST="${KUBERNETES_INGRESS_HOST:-stats-api.example.com}"

# Container Registry
CONTAINER_REGISTRY_URL="${CONTAINER_REGISTRY_URL:-127.0.0.1}"
CONTAINER_REGISTRY_USERNAME="${CONTAINER_REGISTRY_USERNAME:-username}"
CONTAINER_REGISTRY_NAMESPACE="${CONTAINER_REGISTRY_NAMESPACE:-username}"
CONTAINER_REGISTRY_PASSWORD="${CONTAINER_REGISTRY_PASSWORD:-password}"
CONTAINER_IMAGE_NAME="${CONTAINER_IMAGE_NAME:-stats-api}"
CONTAINER_IMAGE_TAG="${CONTAINER_IMAGE_TAG:-latest}"

# Application Configuration
DATABASE_DSN="${DATABASE_DSN:-postgres://postgres:password@localhost:5432/steam_union?sslmode=disable}"

# =============================================================================
# Functions
# =============================================================================

# Print help message
print_help() {
    echo "Usage: $0 [OPTIONS]"
    echo ""
    echo "Environment Variables:"
    echo "  KUBECONFIG_DATA              Kubernetes config data (base64 encoded)"
    echo "  KUBERNETES_URL               Kubernetes API URL (default: https://kubernetes.default.svc)"
    echo "  KUBERNETES_NAMESPACE         Kubernetes namespace (default: default)"
    echo "  KUBERNETES_INGRESS_HOST      Ingress host (default: stats-api.example.com)"
    echo "  CONTAINER_REGISTRY_URL       Container registry URL (default: 127.0.0.1)"
    echo "  CONTAINER_REGISTRY_USERNAME  Registry username"
    echo "  CONTAINER_REGISTRY_PASSWORD  Registry password"
    echo "  CONTAINER_IMAGE_NAME         Image name (default: stats-api)"
    echo "  CONTAINER_IMAGE_TAG          Image tag (default: latest)"
    echo "  DATABASE_DSN                 Database connection string"
    echo ""
    echo "Commands:"
    echo "  deploy      Deploy application to Kubernetes"
    echo "  help        Show this help message (default)"
}

# Setup kubectl configuration
setup_kubectl() {
    echo "Setting up kubectl configuration..."
    
    if [ -z "${KUBECONFIG_DATA}" ]; then
        echo "✗ KUBECONFIG_DATA is not set"
        return 1
    fi
    
    mkdir -p ~/.kube
    echo "${KUBECONFIG_DATA}" | base64 -d > ~/.kube/config
    chmod 600 ~/.kube/config
    
    echo "✓ kubectl configured"
    return 0
}

# Create namespace if it doesn't exist
create_namespace() {
    echo "Checking namespace: ${KUBERNETES_NAMESPACE}"
    
    kubectl get namespace "${KUBERNETES_NAMESPACE}" &> /dev/null
    
    if [ $? -ne 0 ]; then
        echo "Creating namespace: ${KUBERNETES_NAMESPACE}"
        kubectl create namespace "${KUBERNETES_NAMESPACE}"
    else
        echo "✓ Namespace exists: ${KUBERNETES_NAMESPACE}"
    fi
}

# Create image pull secret
create_image_pull_secret() {
    echo "Creating image pull secret..."
    
    kubectl create secret docker-registry regcred \
        --docker-server="${CONTAINER_REGISTRY_URL}" \
        --docker-username="${CONTAINER_REGISTRY_USERNAME}" \
        --docker-password="${CONTAINER_REGISTRY_PASSWORD}" \
        --namespace="${KUBERNETES_NAMESPACE}" \
        --dry-run=client -o yaml | kubectl apply -f -
    
    echo "✓ Image pull secret created/updated"
}

# Deploy to Kubernetes
deploy_to_kubernetes() {
    FULL_IMAGE_NAME="${CONTAINER_REGISTRY_URL}/${CONTAINER_REGISTRY_NAMESPACE}/${CONTAINER_IMAGE_NAME}:${CONTAINER_IMAGE_TAG}"
    
    echo "=========================================="
    echo "Deploying to Kubernetes"
    echo "=========================================="
    echo "Namespace: ${KUBERNETES_NAMESPACE}"
    echo "Image: ${FULL_IMAGE_NAME}"
    echo "Host: ${KUBERNETES_INGRESS_HOST}"
    echo "Database DSN: ${DATABASE_DSN}"
    echo ""
    
    # Setup kubectl
    setup_kubectl || return 1
    
    # Create namespace
    create_namespace || return 1
    
    # Create image pull secret
    create_image_pull_secret || return 1
    
    # Apply Kubernetes manifests with variable substitution
    echo "Applying Kubernetes manifests..."
    
    export FULL_IMAGE_NAME
    export KUBERNETES_NAMESPACE
    export KUBERNETES_INGRESS_HOST
    export CONTAINER_IMAGE_NAME
    export DATABASE_DSN
    
    for file in script/k8s/*.yaml; do
        echo "Applying: $(basename $file)"
        envsubst < "$file" | kubectl apply -f -
    done
    
    echo ""
    echo "✓ Deployment complete"
    echo ""
    echo "Waiting for rollout..."
    kubectl rollout status deployment/${CONTAINER_IMAGE_NAME} -n ${KUBERNETES_NAMESPACE} --timeout=300s
    
    if [ $? -eq 0 ]; then
        echo ""
        echo "✓ Application is ready"
        echo "URL: http://${KUBERNETES_INGRESS_HOST}"
        return 0
    else
        echo ""
        echo "✗ Rollout failed or timed out"
        return 1
    fi
}

# =============================================================================
# Main Script
# =============================================================================

case "${1:-help}" in
    deploy)
        deploy_to_kubernetes
        ;;
    help|*)
        print_help
        ;;
esac