package handler

import (
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"strings"
	"time"

	"sql-platform/internal/model"

	"github.com/gin-gonic/gin"
	"github.com/go-ldap/ldap/v3"
)

// GET /api/v1/ldap-config
func GetLDAPConfig(c *gin.Context) {
	var configs []model.LDAPConfig
	model.DB.Order("id").Find(&configs)
	if len(configs) == 0 {
		c.JSON(http.StatusOK, nil)
		return
	}
	cfg := configs[0]
	// mask password in response
	cfg.AdminPassword = "******"

	// Parse user_mapping from JSON string to object for frontend
	type ldapResponse struct {
		model.LDAPConfig
		UserMapping interface{} `json:"user_mapping"`
	}
	resp := ldapResponse{LDAPConfig: cfg}
	if cfg.UserMapping != nil && *cfg.UserMapping != "" {
		var mapping map[string]string
		json.Unmarshal([]byte(*cfg.UserMapping), &mapping)
		resp.UserMapping = mapping
	} else {
		resp.UserMapping = map[string]string{"username": "uid", "email": "mail", "display_name": "cn"}
	}
	c.JSON(http.StatusOK, resp)
}

// PUT /api/v1/ldap-config
func UpdateLDAPConfig(c *gin.Context) {
	var input map[string]interface{}
	if err := c.ShouldBindJSON(&input); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}

	var configs []model.LDAPConfig
	model.DB.Order("id").Find(&configs)

	// Helper to get string from input
	getStr := func(key string) string {
		if v, ok := input[key].(string); ok {
			return v
		}
		return ""
	}
	getInt := func(key string) int {
		if v, ok := input[key].(float64); ok {
			return int(v)
		}
		return 0
	}
	getBool := func(key string) *bool {
		if v, ok := input[key].(bool); ok {
			return &v
		}
		return nil
	}

	// Serialize user_mapping to JSON string
	userMappingStr := ""
	if um, ok := input["user_mapping"]; ok {
		if bytes, err := json.Marshal(um); err == nil {
			userMappingStr = string(bytes)
		}
	}

	if len(configs) == 0 {
		// Create new config
		cfg := model.LDAPConfig{
			LDAPHost:   getStr("ldap_host"),
			AdminDN:    getStr("admin_dn"),
			BaseDN:     getStr("base_dn"),
			SearchFilter: func() *string { s := getStr("search_filter"); if s != "" { return &s }; return nil }(),
			UserMapping:  func() *string { s := userMappingStr; if s != "" { return &s }; return nil }(),
		}
		if port := getInt("ldap_port"); port > 0 {
			cfg.LDAPPort = &port
		}
		if b := getBool("use_ldaps"); b != nil {
			cfg.UseLDAPS = b
		}
		if pw := getStr("admin_password"); pw != "" && pw != "******" {
			encPw, _ := encryptPassword(pw)
			cfg.AdminPassword = encPw
		}
		model.DB.Create(&cfg)
		cfg.AdminPassword = "******"
		c.JSON(http.StatusOK, cfg)
	} else {
		// Update existing
		cfg := configs[0]
		updates := map[string]interface{}{}

		if v := getStr("ldap_host"); v != "" {
			updates["ldap_host"] = v
		}
		if v := getStr("base_dn"); v != "" {
			updates["base_dn"] = v
		}
		if v := getStr("admin_dn"); v != "" {
			updates["admin_dn"] = v
		}
		if v := getStr("search_filter"); v != "" {
			updates["search_filter"] = v
		}
		if userMappingStr != "" {
			updates["user_mapping"] = userMappingStr
		}
		if v := getStr("admin_password"); v != "" && v != "******" {
			encPw, _ := encryptPassword(v)
			updates["admin_password"] = encPw
		}
		if port := getInt("ldap_port"); port > 0 {
			updates["ldap_port"] = port
		}
		if b := getBool("use_ldaps"); b != nil {
			updates["use_ldaps"] = *b
		}
		if len(updates) > 0 {
			model.DB.Model(&cfg).Updates(updates)
		}
		model.DB.First(&cfg, cfg.ID)
		cfg.AdminPassword = "******"
		c.JSON(http.StatusOK, cfg)
	}
}

// POST /api/v1/ldap-config/test
func TestLDAPConnection(c *gin.Context) {
	var req struct {
		TestUser     string `json:"test_user"`
		TestPassword string `json:"test_password"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": err.Error()})
		return
	}

	var cfg model.LDAPConfig
	if err := model.DB.Order("id").First(&cfg).Error; err != nil {
		c.JSON(http.StatusNotFound, gin.H{"detail": "LDAP 配置不存在，请先保存配置"})
		return
	}
	if cfg.LDAPHost == "" {
		c.JSON(http.StatusBadRequest, gin.H{"success": false, "message": "LDAP 未配置"})
		return
	}

	// Connect
	conn, err := dialLDAP(&cfg)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "message": fmt.Sprintf("连接失败: %s", err)})
		return
	}
	defer conn.Close()

	// Admin bind (decrypt password)
	adminPw, _ := decryptPassword(cfg.AdminPassword)
	if err := conn.Bind(cfg.AdminDN, adminPw); err != nil {
		c.JSON(http.StatusOK, gin.H{"success": false, "message": fmt.Sprintf("管理员绑定失败: %s", err)})
		return
	}

	// If test_user provided, search and verify
	if req.TestUser != "" && req.TestPassword != "" && req.TestPassword != "__use_stored__" {
		userFilter := ""
		if cfg.SearchFilter != nil && *cfg.SearchFilter != "" {
			sf := *cfg.SearchFilter
			if strings.Contains(sf, "%s") {
				userFilter = strings.ReplaceAll(sf, "%s", ldap.EscapeFilter(req.TestUser))
			} else {
				userFilter = fmt.Sprintf("(&%s(uid=%s))", sf, ldap.EscapeFilter(req.TestUser))
			}
		} else {
			userFilter = fmt.Sprintf("(uid=%s)", ldap.EscapeFilter(req.TestUser))
		}

		sr, err := conn.Search(ldap.NewSearchRequest(
			cfg.BaseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
			1, 10, false, userFilter,
			[]string{"uid", "cn", "mail", "telephoneNumber", "title", "department", "memberOf", "distinguishedName"},
			nil,
		))
		if err != nil || len(sr.Entries) == 0 {
			c.JSON(http.StatusOK, gin.H{"success": false, "message": fmt.Sprintf("未找到用户: %s", req.TestUser)})
			return
		}
		entry := sr.Entries[0]
		userDN := entry.DN

		// Verify password
		if err := conn.Bind(userDN, req.TestPassword); err != nil {
			c.JSON(http.StatusOK, gin.H{"success": false, "message": "密码验证失败"})
			return
		}

		// Extract user info
		userMapping := map[string]string{"username": "uid", "email": "mail", "display_name": "cn"}
		if cfg.UserMapping != nil && *cfg.UserMapping != "" {
			json.Unmarshal([]byte(*cfg.UserMapping), &userMapping)
		}

		userInfo := map[string]string{
			"User lookup":  "successful",
			"User ID":      entry.GetAttributeValue(userMapping["username"]),
			"User DN":      userDN,
			"Display Name": entry.GetAttributeValue(userMapping["display_name"]),
			"Email":        entry.GetAttributeValue(userMapping["email"]),
		}
		if userInfo["Display Name"] == "" {
			userInfo["Display Name"] = req.TestUser
		}

		c.JSON(http.StatusOK, gin.H{
			"success":   true,
			"message":   fmt.Sprintf("用户 %s 验证通过", req.TestUser),
			"user_info": userInfo,
		})
		return
	}

	// Just test server connection
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": fmt.Sprintf("LDAP 服务器 %s 连接成功", cfg.LDAPHost),
	})
}

// POST /api/v1/ldap-config/ou-list
func ListLDAPOUs(c *gin.Context) {
	var cfg model.LDAPConfig
	if err := model.DB.Order("id").First(&cfg).Error; err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}

	conn, err := dialLDAP(&cfg)
	if err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}
	defer conn.Close()

	adminPw, _ := decryptPassword(cfg.AdminPassword)
	if err := conn.Bind(cfg.AdminDN, adminPw); err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}

	sr, err := conn.Search(ldap.NewSearchRequest(
		cfg.BaseDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
		100, 0, false, "(objectClass=organizationalUnit)",
		[]string{"ou", "dn", "description"},
		nil,
	))
	if err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}

	type OuItem struct {
		DN   string `json:"dn"`
		Name string `json:"name"`
	}
	var items []OuItem
	for _, e := range sr.Entries {
		items = append(items, OuItem{
			DN:   e.DN,
			Name: e.GetAttributeValue("ou"),
		})
	}
	c.JSON(http.StatusOK, items)
}

// POST /api/v1/ldap-config/user-list
func ListLDAPUsers(c *gin.Context) {
	var req struct {
		OuDn string `json:"ou_dn"`
	}
	c.ShouldBindJSON(&req)

	var cfg model.LDAPConfig
	if err := model.DB.Order("id").First(&cfg).Error; err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}

	conn, err := dialLDAP(&cfg)
	if err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}
	defer conn.Close()

	adminPw2, _ := decryptPassword(cfg.AdminPassword)
	if err := conn.Bind(cfg.AdminDN, adminPw2); err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}

	searchBase := cfg.BaseDN
	if req.OuDn != "" {
		searchBase = req.OuDn
	}

	baseFilter := "(objectClass=inetOrgPerson)"
	if cfg.SearchFilter != nil && *cfg.SearchFilter != "" {
		sf := *cfg.SearchFilter
		if strings.Contains(sf, "%s") {
			baseFilter = strings.ReplaceAll(sf, "%s", "*")
		} else {
			baseFilter = sf
		}
	}

	sr, err := conn.Search(ldap.NewSearchRequest(
		searchBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
		200, 0, false, baseFilter,
		[]string{"uid", "cn", "mail", "dn"},
		nil,
	))
	if err != nil {
		c.JSON(http.StatusOK, []interface{}{})
		return
	}

	type LdapUser struct {
		DN  string `json:"dn"`
		UID string `json:"uid"`
		CN  string `json:"cn"`
		Mail string `json:"mail"`
	}
	var users []LdapUser
	for _, e := range sr.Entries {
		users = append(users, LdapUser{
			DN:  e.DN,
			UID: e.GetAttributeValue("uid"),
			CN:  e.GetAttributeValue("cn"),
			Mail: e.GetAttributeValue("mail"),
		})
	}
	c.JSON(http.StatusOK, users)
}

// POST /api/v1/ldap-config/create-ou
func CreateLDAPOU(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{"message": "OU created (placeholder)"})
}

// POST /api/v1/ldap-config/create-user
func CreateLDAPUser(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{"message": "User created (placeholder)"})
}

// POST /api/v1/ldap-config/batch-import-ldap
func BatchImportLDAP(c *gin.Context) {
	var req struct {
		OuDn    string   `json:"ou_dn"`
		Role    string   `json:"role"`
		UserIDs []string `json:"user_ids"`
	}
	c.ShouldBindJSON(&req)
	if req.Role == "" {
		req.Role = "developer"
	}

	var cfg model.LDAPConfig
	if err := model.DB.Order("id").First(&cfg).Error; err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 配置不存在"})
		return
	}

	conn, err := dialLDAP(&cfg)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 连接失败: " + err.Error()})
		return
	}
	defer conn.Close()

	adminPw, _ := decryptPassword(cfg.AdminPassword)
	if err := conn.Bind(cfg.AdminDN, adminPw); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 管理员绑定失败"})
		return
	}

	searchBase := cfg.BaseDN
	if req.OuDn != "" {
		searchBase = req.OuDn
	}

	baseFilter := "(objectClass=inetOrgPerson)"
	if cfg.SearchFilter != nil && *cfg.SearchFilter != "" {
		sf := *cfg.SearchFilter
		if strings.Contains(sf, "%s") {
			baseFilter = strings.ReplaceAll(sf, "%s", "*")
		} else {
			baseFilter = sf
		}
	}

	sr, err := conn.Search(ldap.NewSearchRequest(
		searchBase, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases,
		500, 0, false, baseFilter,
		[]string{"uid", "cn", "mail"}, nil,
	))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 搜索失败: " + err.Error()})
		return
	}

	isActive := true
	imported := 0
	skipped := 0
	var results []map[string]string

	for _, entry := range sr.Entries {
		uid := entry.GetAttributeValue("uid")
		if uid == "" {
			continue
		}
		if len(req.UserIDs) > 0 {
			found := false
			for _, id := range req.UserIDs {
				if id == uid { found = true; break }
			}
			if !found { continue }
		}

		cn := entry.GetAttributeValue("cn")
		mail := entry.GetAttributeValue("mail")

		var existing model.User
		err := model.DB.Where("username = ?", uid).First(&existing).Error
		if err == nil {
			// Update existing user
			updates := map[string]interface{}{}
			if cn != "" && cn != existing.DisplayName { updates["display_name"] = cn }
			if mail != "" && (existing.Email == nil || *existing.Email != mail) { updates["email"] = mail }
			if len(updates) > 0 {
				model.DB.Model(&existing).Updates(updates)
			}
			results = append(results, map[string]string{"uid": uid, "status": "updated"})
			skipped++
			continue
		}

		newUser := model.User{
			Username:       uid,
			DisplayName:    cn,
			Role:           req.Role,
			AuthSource:     "ldap",
			IsActive:       &isActive,
			HashedPassword: "-",
		}
		if mail != "" { newUser.Email = &mail }
		if err := model.DB.Create(&newUser).Error; err != nil {
			results = append(results, map[string]string{"uid": uid, "status": "error: " + err.Error()})
			skipped++
			continue
		}
		results = append(results, map[string]string{"uid": uid, "status": "created"})
		imported++
	}

	c.JSON(http.StatusOK, gin.H{
		"message":  fmt.Sprintf("导入完成: %d 新建, %d 更新", imported, skipped),
		"imported": imported,
		"skipped":  skipped,
		"results":  results,
	})
}

// POST /api/v1/ldap-config/delete-user
func DeleteLDAPUser(c *gin.Context) {
	var req struct {
		DN string `json:"dn" binding:"required"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "缺少 dn 参数"})
		return
	}

	var cfg model.LDAPConfig
	if err := model.DB.Order("id").First(&cfg).Error; err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 配置不存在"})
		return
	}

	conn, err := dialLDAP(&cfg)
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 连接失败: " + err.Error()})
		return
	}
	defer conn.Close()

	adminPw, _ := decryptPassword(cfg.AdminPassword)
	if err := conn.Bind(cfg.AdminDN, adminPw); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "LDAP 管理员绑定失败"})
		return
	}

	if err := conn.Del(ldap.NewDelRequest(req.DN, nil)); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"detail": "删除用户失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "用户已从 LDAP 删除"})
}

// helper: dial LDAP with config
func dialLDAP(cfg *model.LDAPConfig) (*ldap.Conn, error) {
	if cfg.LDAPHost == "" {
		return nil, fmt.Errorf("LDAP not configured")
	}
	protocol := "ldap"
	if cfg.UseLDAPS != nil && *cfg.UseLDAPS {
		protocol = "ldaps"
	}
	port := 389
	if cfg.LDAPPort != nil && *cfg.LDAPPort > 0 {
		port = *cfg.LDAPPort
	}
	uri := fmt.Sprintf("%s://%s:%d", protocol, cfg.LDAPHost, port)
	dialer := &net.Dialer{Timeout: 3 * time.Second}
	return ldap.DialURL(uri, ldap.DialWithDialer(dialer))
}