package web

import (
	"dhcp-dns-manager/internal/config"
	"encoding/json"
	"net/http"
	"sync"

	"github.com/gin-gonic/gin"
)

// ConfigManager 配置管理器
type ConfigManager struct {
	configPath string
	config     *config.Config
	mu         sync.RWMutex
}

// NewConfigManager 创建配置管理器
func NewConfigManager(path string) (*ConfigManager, error) {
	cfg, err := config.LoadConfig(path)
	if err != nil {
		return nil, err
	}
	return &ConfigManager{
		configPath: path,
		config:     cfg,
	}, nil
}

// GetConfig 获取配置
func (cm *ConfigManager) GetConfig() *config.Config {
	cm.mu.RLock()
	defer cm.mu.RUnlock()
	return cm.config
}

// SaveConfig 保存配置
func (cm *ConfigManager) SaveConfig(cfg *config.Config) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()
	
	cm.config = cfg
	return cfg.Save(cm.configPath)
}

// UpdateDHCPConfig 更新 DHCP 配置（支持部分更新）
func (cm *ConfigManager) UpdateDHCPConfig(updates map[string]interface{}) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()
	
	// 将更新合并到现有配置
	for key, value := range updates {
		switch key {
		case "enabled":
			if v, ok := value.(bool); ok {
				cm.config.DHCP.Enabled = v
			}
		case "interface":
			if v, ok := value.(string); ok {
				cm.config.DHCP.Interface = v
			}
		case "network":
			if v, ok := value.(string); ok {
				cm.config.DHCP.Network = v
			}
		case "netmask":
			if v, ok := value.(string); ok {
				cm.config.DHCP.Netmask = v
			}
		case "gateway":
			if v, ok := value.(string); ok {
				cm.config.DHCP.Gateway = v
			}
		case "dns_servers":
			if v, ok := value.([]interface{}); ok {
				servers := make([]string, len(v))
				for i, s := range v {
					servers[i] = s.(string)
				}
				cm.config.DHCP.DNSServers = servers
			}
		case "lease_time":
			if v, ok := value.(float64); ok {
				cm.config.DHCP.LeaseTime = int(v)
			}
		case "ip_pool_start":
			if v, ok := value.(string); ok {
				cm.config.DHCP.IPPoolStart = v
			}
		case "ip_pool_end":
			if v, ok := value.(string); ok {
				cm.config.DHCP.IPPoolEnd = v
			}
		case "domain_name":
			if v, ok := value.(string); ok {
				cm.config.DHCP.DomainName = v
			}
		case "ntp_servers":
			if v, ok := value.([]interface{}); ok {
				servers := make([]string, len(v))
				for i, s := range v {
					servers[i] = s.(string)
				}
				cm.config.DHCP.NTPServers = servers
			}
		case "broadcast_address":
			if v, ok := value.(string); ok {
				cm.config.DHCP.BroadcastAddress = v
			}
		case "excluded_ips":
			if v, ok := value.([]interface{}); ok {
				ips := make([]string, len(v))
				for i, ip := range v {
					ips[i] = ip.(string)
				}
				cm.config.DHCP.ExcludedIPs = ips
			}
		}
	}
	
	return cm.config.Save(cm.configPath)
}

// UpdateDNSConfig 更新 DNS 配置（支持部分更新）
func (cm *ConfigManager) UpdateDNSConfig(updates map[string]interface{}) error {
	cm.mu.Lock()
	defer cm.mu.Unlock()
	
	for key, value := range updates {
		switch key {
		case "enabled":
			if v, ok := value.(bool); ok {
				cm.config.DNS.Enabled = v
			}
		case "listen_addr":
			if v, ok := value.(string); ok {
				cm.config.DNS.ListenAddr = v
			}
		case "listen_port":
			if v, ok := value.(float64); ok {
				cm.config.DNS.ListenPort = int(v)
			}
		case "upstream":
			if v, ok := value.([]interface{}); ok {
				servers := make([]string, len(v))
				for i, s := range v {
					servers[i] = s.(string)
				}
				cm.config.DNS.Upstream = servers
			}
		case "cache_size":
			if v, ok := value.(float64); ok {
				cm.config.DNS.CacheSize = int(v)
			}
		case "cache_ttl":
			if v, ok := value.(float64); ok {
				cm.config.DNS.CacheTTL = int(v)
			}
		case "recursion":
			if v, ok := value.(bool); ok {
				cm.config.DNS.Recursion = v
			}
		}
	}
	
	return cm.config.Save(cm.configPath)
}

// handleGetDHCPConfig 获取 DHCP 配置
func (s *Server) handleGetDHCPConfig(c *gin.Context) {
	cm := c.MustGet("configManager").(*ConfigManager)
	cfg := cm.GetConfig()
	c.JSON(http.StatusOK, gin.H{"config": cfg.DHCP})
}

// handleUpdateDHCPConfig 更新 DHCP 配置
func (s *Server) handleUpdateDHCPConfig(c *gin.Context) {
	cm := c.MustGet("configManager").(*ConfigManager)
	
	var updates map[string]interface{}
	if err := c.ShouldBindJSON(&updates); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid JSON: " + err.Error()})
		return
	}
	
	// 验证必填字段
	if network, ok := updates["network"]; ok && network.(string) == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "network is required"})
		return
	}
	
	if err := cm.UpdateDHCPConfig(updates); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Save failed: " + err.Error()})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{"message": "DHCP config updated"})
}

// handleGetDNSConfig 获取 DNS 配置
func (s *Server) handleGetDNSConfig(c *gin.Context) {
	cm := c.MustGet("configManager").(*ConfigManager)
	cfg := cm.GetConfig()
	c.JSON(http.StatusOK, gin.H{"config": cfg.DNS})
}

// handleUpdateDNSConfig 更新 DNS 配置
func (s *Server) handleUpdateDNSConfig(c *gin.Context) {
	cm := c.MustGet("configManager").(*ConfigManager)
	
	var updates map[string]interface{}
	if err := c.ShouldBindJSON(&updates); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid JSON: " + err.Error()})
		return
	}
	
	// 验证端口
	if port, ok := updates["listen_port"]; ok {
		if port.(float64) < 1 || port.(float64) > 65535 {
			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid port"})
			return
		}
	}
	
	if err := cm.UpdateDNSConfig(updates); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Save failed: " + err.Error()})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{"message": "DNS config updated"})
}

// handleGetFullConfig 获取完整配置
func (s *Server) handleGetFullConfig(c *gin.Context) {
	cm := c.MustGet("configManager").(*ConfigManager)
	cfg := cm.GetConfig()
	c.JSON(http.StatusOK, gin.H{
		"dhcp": cfg.DHCP,
		"dns":  cfg.DNS,
		"web":  cfg.Web,
	})
}

// handleRestartService 重启服务
func (s *Server) handleRestartService(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"message": "Restart requested. Please restart the service manually: sudo systemctl restart dhcp-dns-manager",
	})
}

// ExportConfig 导出配置
func (s *Server) handleExportConfig(c *gin.Context) {
	cm := c.MustGet("configManager").(*ConfigManager)
	cfg := cm.GetConfig()
	
	c.Header("Content-Type", "application/json")
	c.Header("Content-Disposition", "attachment; filename=dhcp-dns-config.json")
	c.JSON(http.StatusOK, cfg)
}

// ImportConfig 导入配置
func (s *Server) handleImportConfig(c *gin.Context) {
	file, _, err := c.Request.FormFile("config")
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Failed to upload config file"})
		return
	}
	defer file.Close()
	
	var cfg config.Config
	if err := json.NewDecoder(file).Decode(&cfg); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid config file: " + err.Error()})
		return
	}
	
	cm := c.MustGet("configManager").(*ConfigManager)
	if err := cm.SaveConfig(&cfg); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}
	
	c.JSON(http.StatusOK, gin.H{"message": "Config imported successfully"})
}