#!/bin/bash
# Deploy mdBook documentation to custom server
# Usage: deploy-docs.sh [environment]
# Environments: staging, production, custom

set -euo pipefail

# ============================================================================
# Configuration
# ============================================================================

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
DOCS_DIR="$REPO_ROOT/docs"
BUILD_DIR="$DOCS_DIR/book"
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
LOG_FILE="/tmp/docs-deploy-$TIMESTAMP.log"

# Default environment
ENVIRONMENT="${1:-production}"

# ============================================================================
# Logging
# ============================================================================

log() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] $*" | tee -a "$LOG_FILE"
}

error() {
    echo "[ERROR] $*" | tee -a "$LOG_FILE" >&2
    exit 1
}

success() {
    echo "[✓] $*" | tee -a "$LOG_FILE"
}

# ============================================================================
# Environment Configuration
# ============================================================================

load_config() {
    local env=$1
    local config_file="$SCRIPT_DIR/.deploy-config.$env"

    if [ ! -f "$config_file" ]; then
        error "Configuration file not found: $config_file"
    fi

    log "Loading configuration for environment: $env"
    source "$config_file"

    # Validate required variables
    local required_vars=("DEPLOY_HOST" "DEPLOY_USER" "DEPLOY_PATH" "DEPLOY_METHOD")
    for var in "${required_vars[@]}"; do
        if [ -z "${!var:-}" ]; then
            error "Missing required configuration: $var"
        fi
    done

    success "Configuration loaded"
}

# ============================================================================
# Pre-Flight Checks
# ============================================================================

preflight_checks() {
    log "Running preflight checks..."

    # Check if mdBook is built
    if [ ! -d "$BUILD_DIR" ]; then
        error "Build directory not found: $BUILD_DIR"
    fi

    if [ ! -f "$BUILD_DIR/index.html" ]; then
        error "Built documentation not found: $BUILD_DIR/index.html"
    fi

    # Verify essential files
    local required_files=("index.html" "print.html" "css/general.css" "js/book.js")
    for file in "${required_files[@]}"; do
        if [ ! -f "$BUILD_DIR/$file" ]; then
            error "Missing essential file: $file"
        fi
    done

    # Check connectivity
    case $DEPLOY_METHOD in
        ssh|sftp)
            if ! ssh -o ConnectTimeout=5 "$DEPLOY_USER@$DEPLOY_HOST" "echo ok" > /dev/null 2>&1; then
                error "Cannot connect to $DEPLOY_USER@$DEPLOY_HOST via SSH"
            fi
            ;;
        http)
            if ! curl -sf "$DEPLOY_ENDPOINT/health" > /dev/null 2>&1; then
                log "⚠ Deployment endpoint health check failed (non-blocking)"
            fi
            ;;
    esac

    success "Preflight checks passed"
}

# ============================================================================
# Deployment Methods
# ============================================================================

deploy_ssh() {
    log "Deploying via SSH to $DEPLOY_USER@$DEPLOY_HOST:$DEPLOY_PATH"

    # Create backup on remote
    ssh "$DEPLOY_USER@$DEPLOY_HOST" \
        "mkdir -p $DEPLOY_PATH/backups && \
         [ -d $DEPLOY_PATH/current ] && \
         mv $DEPLOY_PATH/current $DEPLOY_PATH/backups/backup_$TIMESTAMP || true"

    # Upload files
    rsync -avz \
        --delete \
        --exclude '.gitignore' \
        --exclude 'CNAME' \
        "$BUILD_DIR/" \
        "$DEPLOY_USER@$DEPLOY_HOST:$DEPLOY_PATH/current/"

    # Update symlink (atomic)
    ssh "$DEPLOY_USER@$DEPLOY_HOST" \
        "ln -sfT $DEPLOY_PATH/current $DEPLOY_PATH/docs && \
         chmod -R 755 $DEPLOY_PATH/current"

    success "SSH deployment completed"
}

deploy_sftp() {
    log "Deploying via SFTP to $DEPLOY_USER@$DEPLOY_HOST:$DEPLOY_PATH"

    # Create SFTP batch commands
    local sftp_batch=$(mktemp)
    cat > "$sftp_batch" << SFTP_CMDS
cd $DEPLOY_PATH
-mkdir backups
-mkdir current
mput -r $BUILD_DIR/* current/
quit
SFTP_CMDS

    # Execute SFTP batch
    sftp -b "$sftp_batch" "$DEPLOY_USER@$DEPLOY_HOST"
    rm "$sftp_batch"

    success "SFTP deployment completed"
}

deploy_http() {
    log "Deploying via HTTP to $DEPLOY_ENDPOINT"

    # Create temporary tarball
    local tar_file=$(mktemp --suffix=.tar.gz)
    tar -czf "$tar_file" -C "$BUILD_DIR" .

    # Upload via HTTP
    local response=$(curl -s -w "\n%{http_code}" \
        -X POST \
        -H "Authorization: Bearer $DEPLOY_TOKEN" \
        -F "archive=@$tar_file" \
        "$DEPLOY_ENDPOINT/deploy")

    local http_code=$(echo "$response" | tail -n1)
    local body=$(echo "$response" | head -n-1)

    rm "$tar_file"

    if [ "$http_code" != "200" ] && [ "$http_code" != "201" ]; then
        error "HTTP deployment failed (HTTP $http_code): $body"
    fi

    success "HTTP deployment completed (HTTP $http_code)"
}

deploy_docker() {
    log "Deploying via Docker to $DEPLOY_REGISTRY"

    local image="$DEPLOY_REGISTRY/vapora-docs:$ENVIRONMENT-$TIMESTAMP"
    local dockerfile=$(mktemp)

    # Generate Dockerfile
    cat > "$dockerfile" << 'EOF'
FROM nginx:alpine
COPY . /usr/share/nginx/html
EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]
EOF

    # Build image
    log "Building Docker image: $image"
    docker build -f "$dockerfile" -t "$image" "$BUILD_DIR"
    docker tag "$image" "$DEPLOY_REGISTRY/vapora-docs:$ENVIRONMENT-latest"

    # Push image
    log "Pushing image to registry"
    docker push "$image"
    docker push "$DEPLOY_REGISTRY/vapora-docs:$ENVIRONMENT-latest"

    rm "$dockerfile"

    log "Container image available: $image"
    success "Docker deployment completed"
}

deploy_s3() {
    log "Deploying to S3: s3://$AWS_BUCKET/$DEPLOY_PATH"

    aws s3 sync \
        "$BUILD_DIR/" \
        "s3://$AWS_BUCKET/$DEPLOY_PATH/" \
        --delete \
        --region "${AWS_REGION:-us-east-1}" \
        --cache-control "public, max-age=300"

    # Invalidate CloudFront if configured
    if [ -n "${CLOUDFRONT_DISTRIBUTION:-}" ]; then
        log "Invalidating CloudFront distribution"
        aws cloudfront create-invalidation \
            --distribution-id "$CLOUDFRONT_DISTRIBUTION" \
            --paths "/$DEPLOY_PATH/*" \
            --region "${AWS_REGION:-us-east-1}"
    fi

    success "S3 deployment completed"
}

deploy_gcs() {
    log "Deploying to Google Cloud Storage: gs://$GCS_BUCKET/$DEPLOY_PATH"

    gsutil -m rsync -r -d "$BUILD_DIR/" "gs://$GCS_BUCKET/$DEPLOY_PATH/"

    # Set cache control
    gsutil -m setmeta -h "Cache-Control:public, max-age=300" \
        "gs://$GCS_BUCKET/$DEPLOY_PATH/**"

    success "GCS deployment completed"
}

# ============================================================================
# Post-Deployment Verification
# ============================================================================

verify_deployment() {
    log "Verifying deployment..."

    case $DEPLOY_METHOD in
        ssh|sftp)
            # Check if files exist on remote
            ssh "$DEPLOY_USER@$DEPLOY_HOST" \
                "[ -f $DEPLOY_PATH/docs/index.html ] && echo 'Files verified' || exit 1"
            ;;
        http)
            # Hit deployment endpoint
            if ! curl -sf "$DEPLOY_ENDPOINT/health" > /dev/null; then
                log "⚠ Health check failed (deployment may still be in progress)"
            fi
            ;;
        docker)
            log "Docker image deployed: $image"
            ;;
        s3)
            # Verify S3 object
            aws s3 ls "s3://$AWS_BUCKET/$DEPLOY_PATH/index.html" \
                --region "${AWS_REGION:-us-east-1}" > /dev/null
            ;;
        gcs)
            # Verify GCS object
            gsutil stat "gs://$GCS_BUCKET/$DEPLOY_PATH/index.html" > /dev/null
            ;;
    esac

    success "Deployment verified"
}

# ============================================================================
# Rollback
# ============================================================================

rollback() {
    log "Rolling back deployment..."

    case $DEPLOY_METHOD in
        ssh)
            if [ -d "$DEPLOY_PATH/backups/backup_$TIMESTAMP" ]; then
                ssh "$DEPLOY_USER@$DEPLOY_HOST" \
                    "ln -sfT $DEPLOY_PATH/backups/backup_$TIMESTAMP $DEPLOY_PATH/docs"
                success "Rollback completed"
            else
                error "No backup available for rollback"
            fi
            ;;
        *)
            error "Rollback not implemented for deployment method: $DEPLOY_METHOD"
            ;;
    esac
}

# ============================================================================
# Main
# ============================================================================

main() {
    log "Starting documentation deployment"
    log "Environment: $ENVIRONMENT"
    log "Repository: $REPO_ROOT"
    log "Build directory: $BUILD_DIR"
    log "Log file: $LOG_FILE"

    # Load configuration
    load_config "$ENVIRONMENT"

    # Preflight checks
    preflight_checks

    # Deploy based on method
    case $DEPLOY_METHOD in
        ssh)
            deploy_ssh
            ;;
        sftp)
            deploy_sftp
            ;;
        http)
            deploy_http
            ;;
        docker)
            deploy_docker
            ;;
        s3)
            deploy_s3
            ;;
        gcs)
            deploy_gcs
            ;;
        *)
            error "Unknown deployment method: $DEPLOY_METHOD"
            ;;
    esac

    # Verify deployment
    verify_deployment

    success "Documentation deployment completed successfully"
    log "Summary:"
    log "  Environment: $ENVIRONMENT"
    log "  Method: $DEPLOY_METHOD"
    log "  Build size: $(du -sh "$BUILD_DIR" | cut -f1)"
    log "  Timestamp: $TIMESTAMP"
    log "  Log: $LOG_FILE"
}

# Handle errors
trap 'error "Deployment failed at line $LINENO"' ERR

# Run main function
main "$@"