package handlers

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

	"ezops/internal/models"

	"github.com/gin-gonic/gin"
	"github.com/go-ldap/ldap/v3"
	"golang.org/x/crypto/bcrypt"
)

// ListLDAPUsers 列出LDAP用户
// POST /api/v1/admin/ldap-config/users
func (h *LDAPHandler) ListLDAPUsers(c *gin.Context) {
	var req struct {
		OuDn string `json:"ou_dn"`
	}
	c.ShouldBindJSON(&req)

	var cfg models.LDAPConfig
	if err := h.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()
	if err := conn.Bind(cfg.AdminDN, cfg.AdminPassword); 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", "telephoneNumber", "title", "department"},
		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"`
		Phone      string `json:"phone"`
		Title      string `json:"title"`
		Department string `json:"department"`
	}
	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"),
			Phone:      e.GetAttributeValue("telephoneNumber"),
			Title:      e.GetAttributeValue("title"),
			Department: e.GetAttributeValue("department"),
		})
	}
	c.JSON(http.StatusOK, models.Response{Code: 200, Data: users})
}

// BatchImportLDAP 批量导入LDAP用户
// POST /api/v1/admin/ldap-config/import
func (h *LDAPHandler) BatchImportLDAP(c *gin.Context) {
	var req struct {
		Users []struct {
			UID      string `json:"uid"`
			CN       string `json:"cn"`
			Mail     string `json:"mail"`
			Username string `json:"username"`
			Nickname string `json:"nickname"`
			Email    string `json:"email"`
		} `json:"users"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: err.Error()})
		return
	}

	imported := 0
	skipped := 0
	for _, lu := range req.Users {
		uid := lu.UID
		if uid == "" {
			uid = lu.Username
		}
		cn := lu.CN
		if cn == "" {
			cn = lu.Nickname
		}
		mail := lu.Mail
		if mail == "" {
			mail = lu.Email
		}
		if uid == "" {
			skipped++
			continue
		}
		// Check if already exists
		var existing models.User
		if err := h.db.Where("username = ?", uid).First(&existing).Error; err == nil {
			// Already exists, update info
			updates := map[string]interface{}{
				"auth_source": "ldap",
			}
			if cn != "" {
				updates["real_name"] = cn
			}
			if mail != "" {
				updates["email"] = mail
			}
			h.db.Model(&existing).Updates(updates)
			imported++
			continue
		}

		// Create new LDAP user
		user := models.User{
			Username:   uid,
			Password:   "-", // LDAP users don't have local password
			RealName:   cn,
			Email:      mail,
			Status:     1,
			AuthSource: "ldap",
		}
		if err := h.db.Create(&user).Error; err != nil {
			skipped++
			continue
		}
		imported++
	}

	// bcrypt import to avoid unused import error
	_ = bcrypt.MinCost

	c.JSON(http.StatusOK, models.Response{
		Code:    200,
		Message: fmt.Sprintf("导入完成: %d 个用户成功, %d 个跳过", imported, skipped),
		Data:    gin.H{"imported": imported, "skipped": skipped},
	})
}

// CreateLDAPUser 在LDAP中创建用户
// POST /api/v1/admin/ldap-config/create-user
func (h *LDAPHandler) CreateLDAPUser(c *gin.Context) {
	var req struct {
		Username    string `json:"username"`
		Password    string `json:"password"`
		DisplayName string `json:"display_name"`
		Email       string `json:"email"`
		OUDN        string `json:"ou_dn"`
	}
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: err.Error()})
		return
	}
	if req.Username == "" || req.Password == "" {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "用户名和密码不能为空"})
		return
	}

	var configs []models.LDAPConfig
	if err := h.db.Order("id").Find(&configs).Error; err != nil || len(configs) == 0 {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "LDAP未配置"})
		return
	}
	cfg := configs[0]
	port := 389
	if cfg.LDAPPort != nil {
		port = *cfg.LDAPPort
	}
	if req.OUDN == "" {
		req.OUDN = cfg.BaseDN
	}
	userDN := fmt.Sprintf("uid=%s,%s", ldap.EscapeFilter(req.Username), req.OUDN)

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

	uidAttr := mapping["username"]
	if uidAttr == "" {
		uidAttr = "uid"
	}
	mailAttr := mapping["email"]
	if mailAttr == "" {
		mailAttr = "mail"
	}

	conn, err := ldap.DialURL(fmt.Sprintf("ldap://%s:%d", cfg.LDAPHost, port))
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "LDAP连接失败: " + err.Error()})
		return
	}
	defer conn.Close()
	conn.SetTimeout(5 * time.Second)
	if err := conn.Bind(cfg.AdminDN, cfg.AdminPassword); err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "管理员认证失败: " + err.Error()})
		return
	}

	addReq := ldap.NewAddRequest(userDN, nil)
	addReq.Attribute("objectClass", []string{"inetOrgPerson", "organizationalPerson", "person", "top"})
	addReq.Attribute(uidAttr, []string{req.Username})
	addReq.Attribute("cn", []string{req.DisplayName})
	addReq.Attribute("sn", []string{req.DisplayName})
	if req.Email != "" {
		addReq.Attribute(mailAttr, []string{req.Email})
	}
	addReq.Attribute("userPassword", []string{req.Password})
	if err := conn.Add(addReq); err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "创建用户失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "用户创建成功", Data: gin.H{"dn": userDN}})
}

// DeleteLDAPUser 删除LDAP条目（用户或OU）
// POST /api/v1/admin/ldap-config/delete-user
func (h *LDAPHandler) DeleteLDAPUser(c *gin.Context) {
	var req struct {
		DN string `json:"dn"`
	}
	if err := c.ShouldBindJSON(&req); err != nil || req.DN == "" {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "DN不能为空"})
		return
	}

	var configs []models.LDAPConfig
	if err := h.db.Order("id").Find(&configs).Error; err != nil || len(configs) == 0 {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "LDAP未配置"})
		return
	}
	cfg := configs[0]
	port := 389
	if cfg.LDAPPort != nil {
		port = *cfg.LDAPPort
	}

	conn, err := ldap.DialURL(fmt.Sprintf("ldap://%s:%d", cfg.LDAPHost, port))
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "LDAP连接失败: " + err.Error()})
		return
	}
	defer conn.Close()
	conn.SetTimeout(5 * time.Second)
	if err := conn.Bind(cfg.AdminDN, cfg.AdminPassword); err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "管理员认证失败: " + err.Error()})
		return
	}

	delReq := ldap.NewDelRequest(req.DN, nil)
	if err := conn.Del(delReq); err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "删除失败: " + err.Error()})
		return
	}

	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "删除成功"})
}

// UpdateLDAPUser 修改 LDAP 用户属性
// POST /api/v1/admin/ldap-config/update-user
func (h *LDAPHandler) UpdateLDAPUser(c *gin.Context) {
	var req struct {
		DN    string `json:"dn"`
		CN    string `json:"cn"`
		Mail  string `json:"mail"`
		Phone string `json:"phone"`
		Title string `json:"title"`
	}
	if err := c.ShouldBindJSON(&req); err != nil || req.DN == "" {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "DN不能为空"})
		return
	}

	var configs []models.LDAPConfig
	if err := h.db.Order("id").Find(&configs).Error; err != nil || len(configs) == 0 {
		c.JSON(http.StatusBadRequest, models.Response{Code: 400, Message: "LDAP未配置"})
		return
	}
	cfg := configs[0]
	port := 389
	if cfg.LDAPPort != nil {
		port = *cfg.LDAPPort
	}

	conn, err := ldap.DialURL(fmt.Sprintf("ldap://%s:%d", cfg.LDAPHost, port))
	if err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "LDAP连接失败: " + err.Error()})
		return
	}
	defer conn.Close()
	conn.SetTimeout(5 * time.Second)
	if err := conn.Bind(cfg.AdminDN, cfg.AdminPassword); err != nil {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "管理员认证失败: " + err.Error()})
		return
	}

	// 先查当前值，做 diff
	sr, err := conn.Search(ldap.NewSearchRequest(
		req.DN, ldap.ScopeBaseObject, ldap.NeverDerefAliases,
		1, 0, false, "(objectClass=*)",
		[]string{"cn", "mail", "telephoneNumber", "title"},
		nil,
	))
	if err != nil || len(sr.Entries) == 0 {
		c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "用户不存在"})
		return
	}
	entry := sr.Entries[0]

	modReq := ldap.NewModifyRequest(req.DN, nil)
	// cn
	oldCN := entry.GetAttributeValue("cn")
	if req.CN != "" && req.CN != oldCN {
		modReq.Replace("cn", []string{req.CN})
		modReq.Replace("sn", []string{req.CN}) // sn 同步更新
	}
	// mail
	oldMail := entry.GetAttributeValue("mail")
	if req.Mail != oldMail {
		if req.Mail == "" {
			oldVals := entry.GetAttributeValues("mail")
			if len(oldVals) > 0 {
				modReq.Delete("mail", oldVals)
			}
		} else {
			modReq.Replace("mail", []string{req.Mail})
		}
	}
	// telephoneNumber
	oldPhone := entry.GetAttributeValue("telephoneNumber")
	if req.Phone != oldPhone {
		if req.Phone == "" {
			oldVals := entry.GetAttributeValues("telephoneNumber")
			if len(oldVals) > 0 {
				modReq.Delete("telephoneNumber", oldVals)
			}
		} else {
			modReq.Replace("telephoneNumber", []string{req.Phone})
		}
	}
	// title
	oldTitle := entry.GetAttributeValue("title")
	if req.Title != oldTitle {
		if req.Title == "" {
			oldVals := entry.GetAttributeValues("title")
			if len(oldVals) > 0 {
				modReq.Delete("title", oldVals)
			}
		} else {
			modReq.Replace("title", []string{req.Title})
		}
	}

	if len(modReq.Changes) > 0 {
		if err := conn.Modify(modReq); err != nil {
			c.JSON(http.StatusInternalServerError, models.Response{Code: 500, Message: "修改失败: " + err.Error()})
			return
		}
	}

	c.JSON(http.StatusOK, models.Response{Code: 200, Message: "修改成功"})
}