package handler

import (
	"fmt"
	"net/http"
	"runtime"
	"strings"
	"time"

	"github.com/gofiber/fiber/v2"
	"github.com/subconverter-go/internal/config"
	"github.com/subconverter-go/internal/logging"
)

// VersionHandler 版本信息处理器
// 提供应用程序版本和构建信息
type VersionHandler struct {
	logger     *logging.Logger
	configMgr  *config.ConfigManager
	buildTime  time.Time
	gitCommit  string
	gitVersion string
}

// NewVersionHandler 创建新的版本信息处理器
// 返回初始化好的VersionHandler实例
func NewVersionHandler(logger *logging.Logger, configMgr *config.ConfigManager) *VersionHandler {
	return &VersionHandler{
		logger:     logger,
		configMgr:  configMgr,
		buildTime:  getBuildTime(),
		gitCommit:  getGitCommit(),
		gitVersion: getGitVersion(),
	}
}

// HandleVersion 处理版本信息请求
// 返回详细的版本和构建信息
func (h *VersionHandler) HandleVersion(c *fiber.Ctx) error {
	h.logger.Debug("Version info request received")

	// 获取配置信息
	config := h.configMgr.GetConfig()

	// 创建版本信息响应
	version := map[string]interface{}{
		"service":     "subconverter-go",
		"version":     "1.0.0",
		"description": "Proxy subscription converter service",
		"author":      "subconverter-go team",
		"license":     "MIT",
		"homepage":    "https://github.com/subconverter-go/subconverter-go",
		"repository":  "https://github.com/subconverter-go/subconverter-go.git",
	}

	// 添加构建信息
	version["build"] = map[string]interface{}{
		"build_time":  h.buildTime.Format(time.RFC3339),
		"git_commit":  h.gitCommit,
		"git_version": h.gitVersion,
		"go_version":  runtime.Version(),
		"compiler":    runtime.Compiler,
		"platform":    fmt.Sprintf("%s/%s", runtime.GOOS, runtime.GOARCH),
	}

	// 添加运行时信息
	version["runtime"] = map[string]interface{}{
		"goroutines": runtime.NumGoroutine(),
		"cgocalls":   runtime.NumCgoCall(),
		"memory":     "N/A", // 可以添加内存使用情况
	}

	// 添加功能特性信息
	version["features"] = map[string]interface{}{
		"supported_formats": config.Conversion.SupportedTargets,
		"security": map[string]interface{}{
			"rate_limiting": config.Security.RateLimit > 0,
			"cors_enabled":  len(config.Security.CorsOrigins) > 0,
			"auth_enabled":  len(config.Security.AccessTokens) > 0,
		},
		"logging": map[string]interface{}{
			"level":  config.Logging.Level,
			"format": config.Logging.Format,
			"output": config.Logging.Output,
		},
		"server": map[string]interface{}{
			"host":      config.Server.Host,
			"port":      config.Server.Port,
			"framework": "fiber/v2",
		},
	}

	// 添加API信息
	version["api"] = map[string]interface{}{
		"version": "v1",
		"endpoints": []string{
			"GET /health - Health check",
			"GET /version - Version information",
			"GET /ready - Readiness check",
			"GET /live - Liveness check",
			"GET /metrics - Runtime metrics",
			"GET /ping - Connectivity test",
			"GET /sub - Subscription conversion",
			"POST /sub - Subscription conversion",
			"GET /api/targets - Supported targets",
			"POST /api/convert - Convert subscription",
			"GET /api/validate - Validate URL",
		},
	}

	// 添加依赖信息
	version["dependencies"] = map[string]interface{}{
		"fiber": map[string]interface{}{
			"version": "v2.52.9",
			"website": "https://gofiber.io",
		},
		"viper": map[string]interface{}{
			"version": "v1.21.0",
			"website": "https://github.com/spf13/viper",
		},
		"cobra": map[string]interface{}{
			"version": "v1.10.1",
			"website": "https://github.com/spf13/cobra",
		},
		"logrus": map[string]interface{}{
			"version": "v1.8.1",
			"website": "https://github.com/sirupsen/logrus",
		},
	}

	// 设置响应头
	c.Set("Cache-Control", "public, max-age=3600") // 缓存1小时
	c.Set("X-API-Version", "v1")
	c.Set("X-Service-Version", "1.0.0")

	format := c.Query("format")
	accept := c.Get("Accept")
	if strings.EqualFold(format, "plain") || strings.Contains(accept, "text/plain") {
		plain := fmt.Sprintf("%s %s backend\n", version["service"], version["version"])
		c.Set("Content-Type", "text/plain; charset=utf-8")
		return c.Status(http.StatusOK).SendString(plain)
	}

	return c.JSON(version)
}

// HandleCompatibility 处理兼容性信息请求
// 返回与原C++版本的兼容性信息
func (h *VersionHandler) HandleCompatibility(c *fiber.Ctx) error {
	h.logger.Debug("Compatibility info request received")

	// 创建兼容性信息响应
	compatibility := map[string]interface{}{
		"original_version": "subconverter (C++)",
		"go_version":       "subconverter-go",
		"compatibility":    "1:1 functional compatibility",
		"status":           "in development",
	}

	// 添加支持的格式兼容性
	compatibility["format_compatibility"] = map[string]interface{}{
		"input_formats": []string{
			"Shadowsocks (SS)",
			"ShadowsocksR (SSR)",
			"VMess",
			"Trojan",
			"HTTP/Socks5",
			"Telegram links",
		},
		"output_formats": []string{
			"Clash",
			"ClashR",
			"Quantumult",
			"Quantumult X",
			"Loon",
			"Surfboard",
			"Surge (v2, v3, v4)",
			"V2Ray",
		},
		"parameter_compatibility": "100%",
	}

	// 添加API兼容性
	compatibility["api_compatibility"] = map[string]interface{}{
		"endpoints": []string{
			"/sub",
			"/config",
			"/health",
			"/version",
		},
		"parameters": []string{
			"target",
			"url",
			"emoji",
			"udp",
			"include",
			"exclude",
			"group",
			"config",
		},
	}

	// 添加配置文件兼容性
	compatibility["config_compatibility"] = map[string]interface{}{
		"supported": "INI format",
		"structure": "Compatible with original",
		"sections": []string{
			"common",
			"node_pref",
			"userinfo",
			"managed_config",
			"server",
			"ruleset",
		},
	}

	return c.JSON(compatibility)
}

// HandleChangelog 处理变更日志请求
// 返回版本变更历史
func (h *VersionHandler) HandleChangelog(c *fiber.Ctx) error {
	h.logger.Debug("Changelog request received")

	// 创建变更日志响应
	changelog := map[string]interface{}{
		"current_version": "1.0.0",
		"latest_release":  "2024-01-01",
		"changes": []map[string]interface{}{
			{
				"version":     "1.0.0",
				"date":        "2024-01-01",
				"type":        "initial",
				"description": "Initial Go release with 1:1 compatibility to C++ version",
				"features": []string{
					"Complete conversion functionality",
					"HTTP API server",
					"CLI interface",
					"Configuration management",
					"Health checks and metrics",
				},
				"changes": []string{
					"Rewritten in Go language",
					"Improved error handling",
					"Better logging system",
					"Enhanced configuration management",
				},
			},
		},
		"upcoming": []map[string]interface{}{
			{
				"version": "1.1.0",
				"status":  "planned",
				"features": []string{
					"Performance optimizations",
					"Enhanced caching",
					"Additional proxy format support",
					"Web interface",
				},
			},
		},
	}

	return c.JSON(changelog)
}

// getBuildTime 获取构建时间
// 从编译时变量或当前时间获取
func getBuildTime() time.Time {
	// 在实际项目中，这里应该从编译时变量获取
	// 例如: return time.Unix(buildTime, 0)
	return time.Now()
}

// getGitCommit 获取Git提交信息
// 从编译时变量获取
func getGitCommit() string {
	// 在实际项目中，这里应该从编译时变量获取
	// 例如: return gitCommit
	return "development"
}

// getGitVersion 获取Git版本信息
// 从编译时变量获取
func getGitVersion() string {
	// 在实际项目中，这里应该从编译时变量获取
	// 例如: return gitVersion
	return "v1.0.0-dev"
}