package algos

import (
	"fmt"
	"net/url"
	"regexp"
	"strconv"
	"sync"
	"time"
)

// getTimestamp 获取时间戳（辅助函数）
func getTimestamp(unix *int64) int64 {
	if unix == nil {
		return time.Now().Unix()
	}
	return *unix
}

// Sign2 签名方法2（Gorgon 或 8404）
func Sign2(
	params string,
	xSSStub string,
	secDeviceID string,
	cookie string,
	aid int,
	licenseID int,
	sdkVersionStr string,
	sdkVersion int,
	platform int,
	unix *int64,
) map[string]string {
	timestamp := getTimestamp(unix)

	// 根据当前算法选择生成签名
	currentAlgo := GlobalAlgorithmSwitcher.GetCurrentAlgorithm()
	if currentAlgo == "8404" {
		algo := NewAlgo8404(params, timestamp, xSSStub)
		return algo.GetValue()
	}
	
	// 默认使用 Gorgon
	gorgon := NewGorgon(params, timestamp, xSSStub, cookie)
	return gorgon.GetValue()
}

// Sign4 签名方法4（Gorgon + Ladon + Argus）
func Sign4(
	params string,
	xSSStub string,
	secDeviceID string,
	cookie string,
	aid int,
	licenseID int,
	sdkVersionStr string,
	sdkVersion int,
	platform int,
	unix *int64,
) map[string]string {
	timestamp := getTimestamp(unix)

	// 根据当前算法选择生成基础签名
	var result map[string]string
	currentAlgo := GlobalAlgorithmSwitcher.GetCurrentAlgorithm()
	if currentAlgo == "8404" {
		algo := NewAlgo8404(params, timestamp, xSSStub)
		result = algo.GetValue()
	} else {
		// 默认使用 Gorgon
		gorgon := NewGorgon(params, timestamp, xSSStub, cookie)
		result = gorgon.GetValue()
	}

	// 添加 Ladon 和 Argus 签名
	ladon := &Ladon{}
	result["x-ladon"] = ladon.Encrypt(timestamp, licenseID, aid)
	result["x-helios"] = result["x-ladon"] // X-Helios 与 X-Ladon 同值（对齐书源实现）

	argus := &Argus{}
	result["x-argus"] = argus.GetSign(
		params,
		xSSStub,
		timestamp,
		aid,
		licenseID,
		platform,
		secDeviceID,
		sdkVersionStr,
		sdkVersion,
	)

	return result
}

// SignatureInterface 签名接口
type SignatureInterface interface {
	Sign(params, xSSStub, secDeviceID, cookie string, aid, licenseID int, sdkVersionStr string, sdkVersion, platform int, unix *int64) map[string]string
}

// SignatureSwitcher 签名方法切换器
type SignatureSwitcher struct {
	mu              sync.RWMutex
	currentMethod   string
	methods         map[string]SignatureInterface
}

// NewSignatureSwitcher 创建签名切换器
func NewSignatureSwitcher() *SignatureSwitcher {
	switcher := &SignatureSwitcher{
		methods: make(map[string]SignatureInterface),
	}
	
	// 注册所有签名方法
	switcher.methods["sign2"] = &Sign2Method{}
	switcher.methods["sign4"] = &Sign4Method{}
	
	// 设置默认签名方法为sign2
	switcher.currentMethod = "sign2"
	
	return switcher
}

// SwitchSignature 切换签名方法
func (s *SignatureSwitcher) SwitchSignature(method string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	
	if _, exists := s.methods[method]; !exists {
		return fmt.Errorf("不支持的签名方法: %s", method)
	}
	
	s.currentMethod = method
	return nil
}

// GetCurrentMethod 获取当前签名方法
func (s *SignatureSwitcher) GetCurrentMethod() string {
	s.mu.RLock()
	defer s.mu.RUnlock()
	return s.currentMethod
}

// Sign 使用当前签名方法进行签名
func (s *SignatureSwitcher) Sign(urlStr string, headers map[string]string) map[string]string {
	return SignFromURL(s.GetCurrentMethod(), urlStr, headers)
}

// SignFromParams 使用当前签名方法进行签名
func (s *SignatureSwitcher) SignFromParams(params, xSSStub, secDeviceID, cookie string, aid, licenseID int, sdkVersionStr string, sdkVersion, platform int, unix *int64) map[string]string {
	s.mu.RLock()
	method := s.methods[s.currentMethod]
	s.mu.RUnlock()
	
	return method.Sign(params, xSSStub, secDeviceID, cookie, aid, licenseID, sdkVersionStr, sdkVersion, platform, unix)
}

// Sign2Method Sign2签名方法实现
type Sign2Method struct{}

func (s *Sign2Method) Sign(params, xSSStub, secDeviceID, cookie string, aid, licenseID int, sdkVersionStr string, sdkVersion, platform int, unix *int64) map[string]string {
	return Sign2(params, xSSStub, secDeviceID, cookie, aid, licenseID, sdkVersionStr, sdkVersion, platform, unix)
}

// Sign4Method Sign4签名方法实现
type Sign4Method struct{}

func (s *Sign4Method) Sign(params, xSSStub, secDeviceID, cookie string, aid, licenseID int, sdkVersionStr string, sdkVersion, platform int, unix *int64) map[string]string {
	return Sign4(params, xSSStub, secDeviceID, cookie, aid, licenseID, sdkVersionStr, sdkVersion, platform, unix)
}

// GlobalSignatureSwitcher 全局签名切换器实例
var GlobalSignatureSwitcher = NewSignatureSwitcher()

// SignFromURL 从 URL 和 headers 中提取参数并生成签名
func SignFromURL(method, urlStr string, headers map[string]string) map[string]string {
	// 解析 URL
	u, err := url.Parse(urlStr)
	if err != nil {
		return make(map[string]string)
	}

	// 提取查询参数
	params := u.RawQuery
	xSSStub := headers["x-ss-stub"]
	cookie := headers["Cookie"]

	// 从 URL 中提取 device_id 和 aid
	deviceIDRegex := regexp.MustCompile(`device_id=(\d+)`)
	aidRegex := regexp.MustCompile(`aid=(\d+)`)

	deviceIDMatch := deviceIDRegex.FindStringSubmatch(urlStr)
	aidMatch := aidRegex.FindStringSubmatch(urlStr)

	secDeviceID := ""
	aid := 1967
	if len(deviceIDMatch) > 1 {
		secDeviceID = deviceIDMatch[1]
	}
	if len(aidMatch) > 1 {
		aid, _ = strconv.Atoi(aidMatch[1])
	}

	// 使用固定参数
	licenseID := 1611921764
	sdkVersionStr := "v04.06.01-ml-android"
	sdkVersion := 135004672
	platform := 0

	// 根据方法调用对应的签名函数
	if method == "sign4" {
		return Sign4(params, xSSStub, secDeviceID, cookie, aid, licenseID, sdkVersionStr, sdkVersion, platform, nil)
	}
	return Sign2(params, xSSStub, secDeviceID, cookie, aid, licenseID, sdkVersionStr, sdkVersion, platform, nil)
}

// Sign2Wrapper 硬编码使用 Sign2（从 URL 和 headers 生成签名）
func Sign2Wrapper(urlStr string, headers map[string]string) map[string]string {
	return SignFromURL("sign2", urlStr, headers)
}