package php

import (
	"encoding/json"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"github.com/host-uk/core/pkg/cli"
)

// DockerfileConfig holds configuration for generating a Dockerfile.
type DockerfileConfig struct {
	// PHPVersion is the PHP version to use (default: "8.3").
	PHPVersion string

	// BaseImage is the base Docker image (default: "dunglas/frankenphp").
	BaseImage string

	// PHPExtensions is the list of PHP extensions to install.
	PHPExtensions []string

	// HasAssets indicates if the project has frontend assets to build.
	HasAssets bool

	// PackageManager is the Node.js package manager (npm, pnpm, yarn, bun).
	PackageManager string

	// IsLaravel indicates if this is a Laravel project.
	IsLaravel bool

	// HasOctane indicates if Laravel Octane is installed.
	HasOctane bool

	// UseAlpine uses the Alpine-based image (smaller).
	UseAlpine bool
}

// GenerateDockerfile generates a Dockerfile for a PHP/Laravel project.
// It auto-detects dependencies from composer.json and project structure.
func GenerateDockerfile(dir string) (string, error) {
	config, err := DetectDockerfileConfig(dir)
	if err != nil {
		return "", err
	}

	return GenerateDockerfileFromConfig(config), nil
}

// DetectDockerfileConfig detects configuration from project files.
func DetectDockerfileConfig(dir string) (*DockerfileConfig, error) {
	config := &DockerfileConfig{
		PHPVersion: "8.3",
		BaseImage:  "dunglas/frankenphp",
		UseAlpine:  true,
	}

	// Read composer.json
	composerPath := filepath.Join(dir, "composer.json")
	composerData, err := os.ReadFile(composerPath)
	if err != nil {
		return nil, cli.WrapVerb(err, "read", "composer.json")
	}

	var composer ComposerJSON
	if err := json.Unmarshal(composerData, &composer); err != nil {
		return nil, cli.WrapVerb(err, "parse", "composer.json")
	}

	// Detect PHP version from composer.json
	if phpVersion, ok := composer.Require["php"]; ok {
		config.PHPVersion = extractPHPVersion(phpVersion)
	}

	// Detect if Laravel
	if _, ok := composer.Require["laravel/framework"]; ok {
		config.IsLaravel = true
	}

	// Detect if Octane
	if _, ok := composer.Require["laravel/octane"]; ok {
		config.HasOctane = true
	}

	// Detect required PHP extensions
	config.PHPExtensions = detectPHPExtensions(composer)

	// Detect frontend assets
	config.HasAssets = hasNodeAssets(dir)
	if config.HasAssets {
		config.PackageManager = DetectPackageManager(dir)
	}

	return config, nil
}

// GenerateDockerfileFromConfig generates a Dockerfile from the given configuration.
func GenerateDockerfileFromConfig(config *DockerfileConfig) string {
	var sb strings.Builder

	// Base image
	baseTag := cli.Sprintf("latest-php%s", config.PHPVersion)
	if config.UseAlpine {
		baseTag += "-alpine"
	}

	sb.WriteString("# Auto-generated Dockerfile for FrankenPHP\n")
	sb.WriteString("# Generated by Core Framework\n\n")

	// Multi-stage build for smaller images
	if config.HasAssets {
		// Frontend build stage
		sb.WriteString("# Stage 1: Build frontend assets\n")
		sb.WriteString("FROM node:20-alpine AS frontend\n\n")
		sb.WriteString("WORKDIR /app\n\n")

		// Copy package files based on package manager
		switch config.PackageManager {
		case "pnpm":
			sb.WriteString("RUN corepack enable && corepack prepare pnpm@latest --activate\n\n")
			sb.WriteString("COPY package.json pnpm-lock.yaml ./\n")
			sb.WriteString("RUN pnpm install --frozen-lockfile\n\n")
		case "yarn":
			sb.WriteString("COPY package.json yarn.lock ./\n")
			sb.WriteString("RUN yarn install --frozen-lockfile\n\n")
		case "bun":
			sb.WriteString("RUN npm install -g bun\n\n")
			sb.WriteString("COPY package.json bun.lockb ./\n")
			sb.WriteString("RUN bun install --frozen-lockfile\n\n")
		default: // npm
			sb.WriteString("COPY package.json package-lock.json ./\n")
			sb.WriteString("RUN npm ci\n\n")
		}

		sb.WriteString("COPY . .\n\n")

		// Build command
		switch config.PackageManager {
		case "pnpm":
			sb.WriteString("RUN pnpm run build\n\n")
		case "yarn":
			sb.WriteString("RUN yarn build\n\n")
		case "bun":
			sb.WriteString("RUN bun run build\n\n")
		default:
			sb.WriteString("RUN npm run build\n\n")
		}
	}

	// PHP build stage
	stageNum := 2
	if config.HasAssets {
		sb.WriteString(cli.Sprintf("# Stage %d: PHP application\n", stageNum))
	}
	sb.WriteString(cli.Sprintf("FROM %s:%s AS app\n\n", config.BaseImage, baseTag))

	sb.WriteString("WORKDIR /app\n\n")

	// Install PHP extensions if needed
	if len(config.PHPExtensions) > 0 {
		sb.WriteString("# Install PHP extensions\n")
		sb.WriteString(cli.Sprintf("RUN install-php-extensions %s\n\n", strings.Join(config.PHPExtensions, " ")))
	}

	// Copy composer files first for better caching
	sb.WriteString("# Copy composer files\n")
	sb.WriteString("COPY composer.json composer.lock ./\n\n")

	// Install composer dependencies
	sb.WriteString("# Install PHP dependencies\n")
	sb.WriteString("RUN composer install --no-dev --no-scripts --optimize-autoloader --no-interaction\n\n")

	// Copy application code
	sb.WriteString("# Copy application code\n")
	sb.WriteString("COPY . .\n\n")

	// Run post-install scripts
	sb.WriteString("# Run composer scripts\n")
	sb.WriteString("RUN composer dump-autoload --optimize\n\n")

	// Copy frontend assets if built
	if config.HasAssets {
		sb.WriteString("# Copy built frontend assets\n")
		sb.WriteString("COPY --from=frontend /app/public/build public/build\n\n")
	}

	// Laravel-specific setup
	if config.IsLaravel {
		sb.WriteString("# Laravel setup\n")
		sb.WriteString("RUN php artisan config:cache \\\n")
		sb.WriteString("    && php artisan route:cache \\\n")
		sb.WriteString("    && php artisan view:cache\n\n")

		// Set permissions
		sb.WriteString("# Set permissions for Laravel\n")
		sb.WriteString("RUN chown -R www-data:www-data storage bootstrap/cache \\\n")
		sb.WriteString("    && chmod -R 775 storage bootstrap/cache\n\n")
	}

	// Expose ports
	sb.WriteString("# Expose ports\n")
	sb.WriteString("EXPOSE 80 443\n\n")

	// Health check
	sb.WriteString("# Health check\n")
	sb.WriteString("HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \\\n")
	sb.WriteString("    CMD curl -f http://localhost/up || exit 1\n\n")

	// Start command
	sb.WriteString("# Start FrankenPHP\n")
	if config.HasOctane {
		sb.WriteString("CMD [\"php\", \"artisan\", \"octane:start\", \"--server=frankenphp\", \"--host=0.0.0.0\", \"--port=80\"]\n")
	} else {
		sb.WriteString("CMD [\"frankenphp\", \"run\", \"--config\", \"/etc/caddy/Caddyfile\"]\n")
	}

	return sb.String()
}

// ComposerJSON represents the structure of composer.json.
type ComposerJSON struct {
	Name       string            `json:"name"`
	Require    map[string]string `json:"require"`
	RequireDev map[string]string `json:"require-dev"`
}

// detectPHPExtensions detects required PHP extensions from composer.json.
func detectPHPExtensions(composer ComposerJSON) []string {
	extensionMap := make(map[string]bool)

	// Check for common packages and their required extensions
	packageExtensions := map[string][]string{
		// Database
		"doctrine/dbal":              {"pdo_mysql", "pdo_pgsql"},
		"illuminate/database":        {"pdo_mysql"},
		"laravel/framework":          {"pdo_mysql", "bcmath", "ctype", "fileinfo", "mbstring", "openssl", "tokenizer", "xml"},
		"mongodb/mongodb":            {"mongodb"},
		"predis/predis":              {"redis"},
		"phpredis/phpredis":          {"redis"},
		"laravel/horizon":            {"redis", "pcntl"},
		"aws/aws-sdk-php":            {"curl"},
		"intervention/image":         {"gd"},
		"intervention/image-laravel": {"gd"},
		"spatie/image":               {"gd"},
		"league/flysystem-aws-s3-v3": {"curl"},
		"guzzlehttp/guzzle":          {"curl"},
		"nelmio/cors-bundle":         {},
		// Queues
		"laravel/reverb":          {"pcntl"},
		"php-amqplib/php-amqplib": {"sockets"},
		// Misc
		"moneyphp/money":              {"bcmath", "intl"},
		"symfony/intl":                {"intl"},
		"nesbot/carbon":               {"intl"},
		"spatie/laravel-medialibrary": {"exif", "gd"},
	}

	// Check all require and require-dev dependencies
	allDeps := make(map[string]string)
	for pkg, ver := range composer.Require {
		allDeps[pkg] = ver
	}
	for pkg, ver := range composer.RequireDev {
		allDeps[pkg] = ver
	}

	// Find required extensions
	for pkg := range allDeps {
		if exts, ok := packageExtensions[pkg]; ok {
			for _, ext := range exts {
				extensionMap[ext] = true
			}
		}

		// Check for direct ext- requirements
		if strings.HasPrefix(pkg, "ext-") {
			ext := strings.TrimPrefix(pkg, "ext-")
			// Skip extensions that are built into PHP
			builtIn := map[string]bool{
				"json": true, "ctype": true, "iconv": true,
				"session": true, "simplexml": true, "pdo": true,
				"xml": true, "tokenizer": true,
			}
			if !builtIn[ext] {
				extensionMap[ext] = true
			}
		}
	}

	// Convert to sorted slice
	extensions := make([]string, 0, len(extensionMap))
	for ext := range extensionMap {
		extensions = append(extensions, ext)
	}
	sort.Strings(extensions)

	return extensions
}

// extractPHPVersion extracts a clean PHP version from a composer constraint.
func extractPHPVersion(constraint string) string {
	// Handle common formats: ^8.2, >=8.2, 8.2.*, ~8.2
	constraint = strings.TrimLeft(constraint, "^>=~")
	constraint = strings.TrimRight(constraint, ".*")

	// Extract major.minor
	parts := strings.Split(constraint, ".")
	if len(parts) >= 2 {
		return parts[0] + "." + parts[1]
	}
	if len(parts) == 1 {
		return parts[0] + ".0"
	}

	return "8.3" // default
}

// hasNodeAssets checks if the project has frontend assets.
func hasNodeAssets(dir string) bool {
	packageJSON := filepath.Join(dir, "package.json")
	if _, err := os.Stat(packageJSON); err != nil {
		return false
	}

	// Check for build script in package.json
	data, err := os.ReadFile(packageJSON)
	if err != nil {
		return false
	}

	var pkg struct {
		Scripts map[string]string `json:"scripts"`
	}

	if err := json.Unmarshal(data, &pkg); err != nil {
		return false
	}

	// Check if there's a build script
	_, hasBuild := pkg.Scripts["build"]
	return hasBuild
}

// GenerateDockerignore generates a .dockerignore file content for PHP projects.
func GenerateDockerignore(dir string) string {
	var sb strings.Builder

	sb.WriteString("# Git\n")
	sb.WriteString(".git\n")
	sb.WriteString(".gitignore\n")
	sb.WriteString(".gitattributes\n\n")

	sb.WriteString("# Node\n")
	sb.WriteString("node_modules\n\n")

	sb.WriteString("# Development\n")
	sb.WriteString(".env\n")
	sb.WriteString(".env.local\n")
	sb.WriteString(".env.*.local\n")
	sb.WriteString("*.log\n")
	sb.WriteString(".phpunit.result.cache\n")
	sb.WriteString("phpunit.xml\n")
	sb.WriteString(".php-cs-fixer.cache\n")
	sb.WriteString("phpstan.neon\n\n")

	sb.WriteString("# IDE\n")
	sb.WriteString(".idea\n")
	sb.WriteString(".vscode\n")
	sb.WriteString("*.swp\n")
	sb.WriteString("*.swo\n\n")

	sb.WriteString("# Laravel specific\n")
	sb.WriteString("storage/app/*\n")
	sb.WriteString("storage/logs/*\n")
	sb.WriteString("storage/framework/cache/*\n")
	sb.WriteString("storage/framework/sessions/*\n")
	sb.WriteString("storage/framework/views/*\n")
	sb.WriteString("bootstrap/cache/*\n\n")

	sb.WriteString("# Build artifacts\n")
	sb.WriteString("public/hot\n")
	sb.WriteString("public/storage\n")
	sb.WriteString("vendor\n\n")

	sb.WriteString("# Docker\n")
	sb.WriteString("Dockerfile*\n")
	sb.WriteString("docker-compose*.yml\n")
	sb.WriteString(".dockerignore\n\n")

	sb.WriteString("# Documentation\n")
	sb.WriteString("README.md\n")
	sb.WriteString("CHANGELOG.md\n")
	sb.WriteString("docs\n")

	return sb.String()
}