package generator

import (
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"sort"
	"strconv"
	"strings"

	yaml "gopkg.in/yaml.v3"

	"github.com/subconverter-go/internal/logging"
	"github.com/subconverter-go/internal/parser"
)

// ClashGenerator Clash格式生成器
// 实现Clash代理配置的生成功能
type ClashGenerator struct {
	logger *logging.Logger
}

// NewClashGenerator 创建新的Clash生成器
// 返回初始化好的ClashGenerator实例
func NewClashGenerator(logger *logging.Logger) *ClashGenerator {
	return &ClashGenerator{
		logger: logger,
	}
}

// Generate 生成Clash配置
func (g *ClashGenerator) Generate(configs []*parser.ProxyConfig, options *GenerationOptions) (string, error) {
	g.logger.Debugf("Generating Clash configuration")

	// 创建Clash配置结构
	clashConfig := g.createClashConfig(configs, options)

	// 转换为YAML
	yamlData, err := yaml.Marshal(clashConfig)
	if err != nil {
		return "", fmt.Errorf("failed to marshal Clash configuration: %v", err)
	}

	return string(yamlData), nil
}

// ValidateOptions 验证Clash生成选项
func (g *ClashGenerator) ValidateOptions(options *GenerationOptions) error {
	g.logger.Debugf("Validating Clash generation options")

	// 验证基本信息
	if options.Name == "" {
		return fmt.Errorf("configuration name is required")
	}

	// 验证模式
	validModes := []string{"global", "rule", "direct"}
	if options.Mode != "" {
		valid := false
		for _, mode := range validModes {
			if options.Mode == mode {
				valid = true
				break
			}
		}
		if !valid {
			return fmt.Errorf("invalid mode: %s, must be one of: %s", options.Mode, strings.Join(validModes, ", "))
		}
	}

	// 验证端口
	if options.MixedPort < 0 || options.MixedPort > 65535 {
		return fmt.Errorf("invalid mixed port: %d", options.MixedPort)
	}

	// 验证日志级别
	validLogLevels := []string{"info", "warning", "error", "debug", "silent"}
	if options.LogLevel != "" {
		valid := false
		for _, level := range validLogLevels {
			if options.LogLevel == level {
				valid = true
				break
			}
		}
		if !valid {
			return fmt.Errorf("invalid log level: %s, must be one of: %s", options.LogLevel, strings.Join(validLogLevels, ", "))
		}
	}

	return nil
}

// GetSupportedFormats 获取支持的格式
func (g *ClashGenerator) GetSupportedFormats() []string {
	return []string{"clash"}
}

// ClashConfig Clash配置结构体
type ClashConfig struct {
	Port               int                               `yaml:"port" json:"port"`
	SocksPort          int                               `yaml:"socks-port" json:"socks-port"`
	AllowLan           bool                              `yaml:"allow-lan" json:"allow-lan"`
	Mode               string                            `yaml:"mode" json:"mode"`
	LogLevel           string                            `yaml:"log-level" json:"log-level"`
	ExternalController string                            `yaml:"external-controller" json:"external-controller"`
	Secret             string                            `yaml:"secret,omitempty" json:"secret,omitempty"`
	Proxies            []map[string]interface{}          `yaml:"proxies" json:"proxies"`
	ProxyGroup         []map[string]interface{}          `yaml:"proxy-groups" json:"proxy-groups"`
	Rules              []string                          `yaml:"rules" json:"rules"`
	ProxyProviders     map[string]map[string]interface{} `yaml:"proxy-providers,omitempty" json:"proxy-providers,omitempty"`
}

// createClashConfig 创建Clash配置结构
func (g *ClashGenerator) createClashConfig(configs []*parser.ProxyConfig, options *GenerationOptions) *ClashConfig {
	config := &ClashConfig{
		Port:               7890,
		SocksPort:          7891,
		AllowLan:           options.AllowLan,
		Mode:               options.Mode,
		LogLevel:           options.LogLevel,
		ExternalController: options.ExternalController,
		Secret:             options.Secret,
		Proxies:            make([]map[string]interface{}, 0),
		ProxyGroup:         make([]map[string]interface{}, 0),
		Rules:              make([]string, 0),
	}

	// 设置默认值
	if config.Port == 0 {
		config.Port = 7890
	}
	if config.SocksPort == 0 {
		config.SocksPort = 7891
	}
	if config.Mode == "" {
		config.Mode = "rule"
	}
	if config.LogLevel == "" {
		config.LogLevel = "info"
	}

	// 生成代理配置
	for _, proxyConfig := range configs {
		proxy := g.convertProxyConfig(proxyConfig)
		config.Proxies = append(config.Proxies, proxy)
	}

	// 生成代理组
	config.ProxyGroup = g.createProxyGroups(configs, options)
	if len(options.GroupDefinitions) > 0 {
		for _, def := range options.GroupDefinitions {
			config.ProxyGroup = append(config.ProxyGroup, g.buildClashGroup(def, configs))
		}
	} else if len(options.CustomGroups) > 0 {
		for _, entry := range options.CustomGroups {
			group, err := g.parseCustomGroup(entry, configs)
			if err != nil {
				g.logger.WithError(err).Warnf("Failed to parse custom group: %s", entry)
				continue
			}
			config.ProxyGroup = append(config.ProxyGroup, group)
		}
	}

	if len(options.Providers) > 0 {
		providers := make(map[string]map[string]interface{}, len(options.Providers))
		for _, def := range options.Providers {
			providers[def.Name] = g.buildClashProvider(def)
		}
		config.ProxyProviders = providers
	} else if len(options.CustomProviders) > 0 {
		providers := make(map[string]map[string]interface{})
		for _, entry := range options.CustomProviders {
			parsed, err := ParseProviderDefinition(entry)
			if err != nil {
				g.logger.WithError(err).Warnf("Failed to parse custom provider: %s", entry)
				continue
			}
			providers[parsed.Name] = g.buildClashProvider(parsed)
		}
		if len(providers) > 0 {
			config.ProxyProviders = providers
		}
	}

	// 生成规则
	rules := g.createRules(options)
	config.Rules = g.applyCustomRulesets(rules, options)

	return config
}

// convertProxyConfig 转换代理配置为Clash格式
func (g *ClashGenerator) convertProxyConfig(proxyConfig *parser.ProxyConfig) map[string]interface{} {
	proxy := map[string]interface{}{
		"name":   proxyConfig.Name,
		"type":   proxyConfig.Type,
		"server": proxyConfig.Server,
		"port":   proxyConfig.Port,
		"udp":    proxyConfig.UDP,
	}

	// 根据协议类型添加特定配置
	switch proxyConfig.Protocol {
	case "ss":
		if method, exists := proxyConfig.Settings["method"]; exists {
			proxy["cipher"] = method
		}
		if password, exists := proxyConfig.Settings["password"]; exists {
			proxy["password"] = password
		}
		if plugin, exists := proxyConfig.Settings["plugin"]; exists {
			proxy["plugin"] = plugin
		}

	case "ssr":
		if method, exists := proxyConfig.Settings["method"]; exists {
			proxy["cipher"] = method
		}
		if password, exists := proxyConfig.Settings["password"]; exists {
			proxy["password"] = password
		}
		if protocol, exists := proxyConfig.Settings["protocol"]; exists {
			proxy["protocol"] = protocol
		}
		if obfs, exists := proxyConfig.Settings["obfs"]; exists {
			proxy["obfs"] = obfs
		}

	case "vmess":
		if uuid, exists := proxyConfig.Settings["uuid"]; exists {
			proxy["uuid"] = uuid
		}
		if alterId, exists := proxyConfig.Settings["alterId"]; exists {
			proxy["alterId"] = alterId
		}
		if network, exists := proxyConfig.Settings["network"]; exists {
			proxy["network"] = network
		}
		if tls, exists := proxyConfig.Settings["tls"]; exists {
			proxy["tls"] = tls
		}
		if host, exists := proxyConfig.Settings["host"]; exists {
			proxy["servername"] = host
		}
		if path, exists := proxyConfig.Settings["path"]; exists {
			proxy["ws-path"] = path
		}

	case "trojan":
		if password, exists := proxyConfig.Settings["password"]; exists {
			proxy["password"] = password
		}
		if sni, exists := proxyConfig.Settings["sni"]; exists {
			proxy["sni"] = sni
		}
		if network, exists := proxyConfig.Settings["network"]; exists {
			proxy["network"] = network
		}

	case "http", "https":
		if username, exists := proxyConfig.Settings["username"]; exists {
			proxy["username"] = username
		}
		if password, exists := proxyConfig.Settings["password"]; exists {
			proxy["password"] = password
		}
		if tls, exists := proxyConfig.Settings["tls"]; exists {
			proxy["tls"] = tls
		}

	case "socks5":
		if username, exists := proxyConfig.Settings["username"]; exists {
			proxy["username"] = username
		}
		if password, exists := proxyConfig.Settings["password"]; exists {
			proxy["password"] = password
		}
	}

	return proxy
}

// createProxyGroups 创建代理组
func (g *ClashGenerator) createProxyGroups(configs []*parser.ProxyConfig, options *GenerationOptions) []map[string]interface{} {
	groups := make([]map[string]interface{}, 0)

	// 创建代理名称列表
	proxyNames := make([]string, 0)
	for _, config := range configs {
		proxyNames = append(proxyNames, config.Name)
	}

	// 创建选择代理组
	selectGroup := map[string]interface{}{
		"name":    "PROXY",
		"type":    "select",
		"proxies": proxyNames,
	}
	groups = append(groups, selectGroup)

	// 创建自动选择代理组（如果启用了代理测试）
	if options.ProxyTest {
		urlTestGroup := map[string]interface{}{
			"name":      "URL-TEST",
			"type":      "url-test",
			"proxies":   proxyNames,
			"url":       options.ProxyURL,
			"interval":  300,
			"tolerance": 50,
		}
		if urlTestGroup["url"] == "" {
			urlTestGroup["url"] = "http://www.gstatic.com/generate_204"
		}
		groups = append(groups, urlTestGroup)
	}

	// 创建故障转移代理组
	fallbackGroup := map[string]interface{}{
		"name":     "FALLBACK",
		"type":     "fallback",
		"proxies":  proxyNames,
		"url":      "http://www.gstatic.com/generate_204",
		"interval": 300,
	}
	groups = append(groups, fallbackGroup)

	// 创建直连和拒绝代理组
	groups = append(groups, map[string]interface{}{
		"name":    "DIRECT",
		"type":    "select",
		"proxies": []string{"DIRECT"},
	})

	groups = append(groups, map[string]interface{}{
		"name":    "REJECT",
		"type":    "select",
		"proxies": []string{"REJECT"},
	})

	return groups
}

func (g *ClashGenerator) buildClashGroup(def *GroupDefinition, configs []*parser.ProxyConfig) map[string]interface{} {
	group := map[string]interface{}{
		"name": def.Name,
		"type": def.Type,
	}

	proxies := make([]string, 0, len(def.Proxies))
	proxies = append(proxies, def.Proxies...)
	if len(proxies) == 0 && len(def.UseProviders) == 0 {
		for _, cfg := range configs {
			proxies = append(proxies, cfg.Name)
		}
	}
	if len(proxies) > 0 {
		group["proxies"] = proxies
	}
	if len(def.UseProviders) > 0 {
		group["use"] = def.UseProviders
	}
	if def.URL != "" {
		group["url"] = def.URL
	}
	if def.Interval != nil {
		group["interval"] = *def.Interval
	}
	if def.Timeout != nil {
		group["timeout"] = *def.Timeout
	}
	if def.Tolerance != nil {
		group["tolerance"] = *def.Tolerance
	}
	for k, v := range def.Extras {
		group[k] = v
	}

	return group
}

func (g *ClashGenerator) buildClashProvider(def *ProviderDefinition) map[string]interface{} {
	provider := map[string]interface{}{
		"type": def.Type,
		"url":  def.URL,
		"path": def.Path,
	}
	if def.Interval != nil {
		provider["interval"] = *def.Interval
	}
	if len(def.Fields) > 0 {
		keys := make([]string, 0, len(def.Fields))
		for k := range def.Fields {
			keys = append(keys, k)
		}
		sort.Strings(keys)
		for _, k := range keys {
			provider[k] = def.Fields[k]
		}
	}
	if len(def.Flags) > 0 {
		keys := make([]string, 0, len(def.Flags))
		for k := range def.Flags {
			keys = append(keys, k)
		}
		sort.Strings(keys)
		for _, k := range keys {
			provider[k] = def.Flags[k]
		}
	}
	if def.Health != nil {
		health := make(map[string]interface{})
		if def.Health.Enable != nil {
			health["enable"] = *def.Health.Enable
		}
		if def.Health.URL != "" {
			health["url"] = def.Health.URL
		}
		if def.Health.Interval != nil {
			health["interval"] = *def.Health.Interval
		}
		if def.Health.Lazy != nil {
			health["lazy"] = *def.Health.Lazy
		}
		if def.Health.Tolerance != nil {
			health["tolerance"] = *def.Health.Tolerance
		}
		if def.Health.Timeout != nil {
			health["timeout"] = *def.Health.Timeout
		}
		if def.Health.Method != "" {
			health["method"] = def.Health.Method
		}
		if def.Health.Headers != "" {
			health["headers"] = def.Health.Headers
		}
		if len(health) > 0 {
			provider["health-check"] = health
		}
	}

	return provider
}

// createRules 创建规则
func (g *ClashGenerator) createRules(options *GenerationOptions) []string {
	rules := make([]string, 0)

	// 添加默认规则
	if len(options.Rules) > 0 {
		rules = append(rules, options.Rules...)
	} else {
		// 添加默认规则集
		defaultRules := []string{
			"DOMAIN-SUFFIX,bilibili.com,DIRECT",
			"DOMAIN-SUFFIX,baidu.com,DIRECT",
			"DOMAIN-SUFFIX,cn,DIRECT",
			"DOMAIN-KEYWORD,google,PROXY",
			"DOMAIN-KEYWORD,github,PROXY",
			"DOMAIN-KEYWORD,twitter,PROXY",
			"DOMAIN-KEYWORD,facebook,PROXY",
			"DOMAIN-KEYWORD,youtube,PROXY",
			"DOMAIN-KEYWORD,instagram,PROXY",
			"DOMAIN-KEYWORD,telegram,PROXY",
			"GEOIP,CN,DIRECT",
			"IP-CIDR,127.0.0.0/8,DIRECT",
			"IP-CIDR,192.168.0.0/16,DIRECT",
			"IP-CIDR,10.0.0.0/8,DIRECT",
			"IP-CIDR,172.16.0.0/12,DIRECT",
			"MATCH,PROXY",
		}
		rules = append(rules, defaultRules...)
	}

	// 启用IPv6支持
	if options.IPv6 {
		ipv6Rules := []string{
			"IP-CIDR6,::1/128,DIRECT",
			"IP-CIDR6,fc00::/7,DIRECT",
		}
		rules = append(ipv6Rules, rules...)
	}

	// 启用局域网支持
	if options.EnableLan {
		lanRules := []string{
			"SRC-IP-CIDR,192.168.0.0/16,DIRECT",
			"SRC-IP-CIDR,10.0.0.0/8,DIRECT",
			"SRC-IP-CIDR,172.16.0.0/12,DIRECT",
		}
		rules = append(lanRules, rules...)
	}

	return rules
}

func (g *ClashGenerator) parseCustomGroup(definition string, configs []*parser.ProxyConfig) (map[string]interface{}, error) {
	values, err := url.ParseQuery(definition)
	if err != nil {
		return nil, fmt.Errorf("invalid group definition: %v", err)
	}

	name := values.Get("name")
	if name == "" {
		return nil, fmt.Errorf("custom group missing name")
	}

	groupType := values.Get("type")
	if groupType == "" {
		groupType = "select"
	}

	useProviders := make([]string, 0)
	if useStr := values.Get("use"); useStr != "" {
		for _, entry := range strings.Split(useStr, ",") {
			entry = strings.TrimSpace(entry)
			if entry != "" {
				useProviders = append(useProviders, entry)
			}
		}
	}

	proxies := make([]string, 0)
	if proxyStr := values.Get("proxies"); proxyStr != "" {
		for _, entry := range strings.Split(proxyStr, ",") {
			entry = strings.TrimSpace(entry)
			if entry != "" {
				proxies = append(proxies, entry)
			}
		}
	}

	if len(proxies) == 0 && len(useProviders) == 0 {
		for _, cfg := range configs {
			proxies = append(proxies, cfg.Name)
		}
	}

	group := map[string]interface{}{
		"name":    name,
		"type":    groupType,
		"proxies": proxies,
	}
	if len(useProviders) > 0 {
		group["use"] = useProviders
	}

	if urlValue := values.Get("url"); urlValue != "" {
		group["url"] = urlValue
	}
	if interval := values.Get("interval"); interval != "" {
		if n, err := strconv.Atoi(interval); err == nil && n > 0 {
			group["interval"] = n
		}
	}
	if tolerance := values.Get("tolerance"); tolerance != "" {
		if n, err := strconv.Atoi(tolerance); err == nil && n >= 0 {
			group["tolerance"] = n
		}
	}
	if timeout := values.Get("timeout"); timeout != "" {
		if n, err := strconv.Atoi(timeout); err == nil && n >= 0 {
			group["timeout"] = n
		}
	}

	return group, nil
}

func (g *ClashGenerator) applyCustomRulesets(existing []string, options *GenerationOptions) []string {
	rules := make([]string, 0, len(existing))
	for _, rule := range existing {
		rule = strings.TrimSpace(rule)
		if rule == "" {
			continue
		}
		rules = append(rules, rule)
	}

	for _, entry := range options.CustomRulesets {
		entry = strings.TrimSpace(entry)
		if entry == "" {
			continue
		}
		lower := strings.ToLower(entry)
		switch {
		case strings.HasPrefix(lower, "ruleset,"):
			payload := strings.TrimSpace(entry[len("ruleset,"):])
			if payload == "" {
				continue
			}
			lines, err := g.loadRulesetLines(options.BasePath, payload)
			if err != nil {
				g.logger.WithError(err).Warnf("Failed to load ruleset %s", payload)
				continue
			}
			rules = append(rules, lines...)
		case strings.HasPrefix(lower, "rule,"):
			statement := strings.TrimSpace(entry[len("rule,"):])
			if statement != "" {
				rules = append(rules, statement)
			}
		default:
			rules = append(rules, entry)
		}
	}

	return normalizeRules(rules)
}

func (g *ClashGenerator) loadRulesetLines(basePath, relative string) ([]string, error) {
	path := relative
	if basePath != "" && !filepath.IsAbs(relative) {
		path = filepath.Join(basePath, relative)
	}
	data, err := os.ReadFile(path)
	if err != nil {
		return nil, err
	}

	content := strings.ReplaceAll(string(data), "\r\n", "\n")
	lines := make([]string, 0)
	for _, line := range strings.Split(content, "\n") {
		trimmed := strings.TrimSpace(line)
		if trimmed == "" {
			continue
		}
		if strings.HasPrefix(trimmed, "#") || strings.HasPrefix(trimmed, "//") {
			continue
		}
		lines = append(lines, trimmed)
	}
	return lines, nil
}

func normalizeRules(rules []string) []string {
	seen := make(map[string]struct{})
	result := make([]string, 0, len(rules))
	for _, rule := range rules {
		rule = strings.TrimSpace(rule)
		if rule == "" {
			continue
		}
		if _, ok := seen[rule]; ok {
			continue
		}
		seen[rule] = struct{}{}
		result = append(result, rule)
	}
	return result
}