package controller

import (
	"encoding/json"
	"github.com/gin-contrib/sessions"
	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
	"message-pusher/channel"
	"message-pusher/common"
	"message-pusher/model"
	"net/http"
	"strconv"
	"strings"
)

type LoginRequest struct {
	Username string `json:"username"`
	Password string `json:"password"`
}

func Login(c *gin.Context) {
	if !common.PasswordLoginEnabled {
		c.JSON(http.StatusOK, gin.H{
			"message": "管理员关闭了密码登录",
			"success": false,
		})
		return
	}
	var loginRequest LoginRequest
	err := json.NewDecoder(c.Request.Body).Decode(&loginRequest)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"message": "无效的参数",
			"success": false,
		})
		return
	}
	username := loginRequest.Username
	password := loginRequest.Password
	if username == "" || password == "" {
		c.JSON(http.StatusOK, gin.H{
			"message": "无效的参数",
			"success": false,
		})
		return
	}
	user := model.User{
		Username: username,
		Password: password,
	}
	err = user.ValidateAndFill()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"message": err.Error(),
			"success": false,
		})
		return
	}
	setupLogin(&user, c)
}

// setup session & cookies and then return user info
func setupLogin(user *model.User, c *gin.Context) {
	session := sessions.Default(c)
	session.Set("id", user.Id)
	session.Set("username", user.Username)
	session.Set("role", user.Role)
	session.Set("status", user.Status)
	err := session.Save()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"message": "无法保存会话信息，请重试",
			"success": false,
		})
		return
	}
	cleanUser := model.User{
		Id:          user.Id,
		Username:    user.Username,
		DisplayName: user.DisplayName,
		Role:        user.Role,
		Status:      user.Status,
	}
	c.JSON(http.StatusOK, gin.H{
		"message": "",
		"success": true,
		"data":    cleanUser,
	})
}

func Logout(c *gin.Context) {
	session := sessions.Default(c)
	session.Clear()
	err := session.Save()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"message": err.Error(),
			"success": false,
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"message": "",
		"success": true,
	})
}

func Register(c *gin.Context) {
	if !common.RegisterEnabled {
		c.JSON(http.StatusOK, gin.H{
			"message": "管理员关闭了新用户注册",
			"success": false,
		})
		return
	}
	if !common.PasswordRegisterEnabled {
		c.JSON(http.StatusOK, gin.H{
			"message": "管理员关闭了通过密码进行注册，请使用第三方账户验证的形式进行注册",
			"success": false,
		})
		return
	}
	var user model.User
	err := json.NewDecoder(c.Request.Body).Decode(&user)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无效的参数",
		})
		return
	}
	if err := common.Validate.Struct(&user); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "输入不合法 " + err.Error(),
		})
		return
	}
	if common.EmailVerificationEnabled {
		if user.Email == "" || user.VerificationCode == "" {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "管理员开启了邮箱验证，请输入邮箱地址和验证码",
			})
			return
		}
		if !common.VerifyCodeWithKey(user.Email, user.VerificationCode, common.EmailVerificationPurpose) {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "验证码错误或已过期",
			})
			return
		}
	}
	cleanUser := model.User{
		Username:    user.Username,
		Password:    user.Password,
		DisplayName: user.Username,
	}
	if common.EmailVerificationEnabled {
		cleanUser.Email = user.Email
	}
	if err := cleanUser.Insert(); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}

func GetAllUsers(c *gin.Context) {
	p, _ := strconv.Atoi(c.Query("p"))
	if p < 0 {
		p = 0
	}
	users, err := model.GetAllUsers(p*common.ItemsPerPage, common.ItemsPerPage)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"data":    users,
	})
	return
}

func SearchUsers(c *gin.Context) {
	keyword := c.Query("keyword")
	users, err := model.SearchUsers(keyword)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"data":    users,
	})
	return
}

func GetUser(c *gin.Context) {
	id, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	user, err := model.GetUserById(id, false)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	myRole := c.GetInt("role")
	if myRole <= user.Role {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无权获取同级或更高等级用户的信息",
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"data":    user,
	})
	return
}

func GenerateToken(c *gin.Context) {
	id := c.GetInt("id")
	user, err := model.GetUserById(id, true)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	user.Token = uuid.New().String()
	user.Token = strings.Replace(user.Token, "-", "", -1)

	if model.DB.Where("token = ?", user.Token).First(user).RowsAffected != 0 {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "请重试，系统生成的 UUID 竟然重复了！",
		})
		return
	}

	if err := user.Update(false); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"data":    user.Token,
	})
	return
}

func GetSelf(c *gin.Context) {
	id := c.GetInt("id")
	user, err := model.GetUserById(id, false)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"data":    user,
	})
	return
}

func UpdateUser(c *gin.Context) {
	var updatedUser model.User
	err := json.NewDecoder(c.Request.Body).Decode(&updatedUser)
	if err != nil || updatedUser.Id == 0 {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无效的参数",
		})
		return
	}
	if updatedUser.Password == "" {
		updatedUser.Password = "$I_LOVE_U" // make Validator happy :)
	}
	if err := common.Validate.Struct(&updatedUser); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "输入不合法 " + err.Error(),
		})
		return
	}
	originUser, err := model.GetUserById(updatedUser.Id, false)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	myRole := c.GetInt("role")
	if myRole <= originUser.Role {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无权更新同权限等级或更高权限等级的用户信息",
		})
		return
	}
	if myRole <= updatedUser.Role {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无权将其他用户权限等级提升到大于等于自己的权限等级",
		})
		return
	}
	if updatedUser.Password == "$I_LOVE_U" {
		updatedUser.Password = "" // rollback to what it should be
	}
	// We only allow admin change those fields.
	cleanUser := model.User{
		Id:          updatedUser.Id,
		Username:    updatedUser.Username,
		Password:    updatedUser.Password,
		DisplayName: updatedUser.DisplayName,
	}
	updatePassword := cleanUser.Password != ""
	if err := cleanUser.Update(updatePassword); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}

func UpdateSelf(c *gin.Context) {
	var user model.User
	err := json.NewDecoder(c.Request.Body).Decode(&user)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无效的参数",
		})
		return
	}
	if user.Password == "" {
		user.Password = "$I_LOVE_U" // make Validator happy :)
	}
	if err := common.Validate.Struct(&user); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "输入不合法 " + err.Error(),
		})
		return
	}
	// White list mode. For safe :)
	cleanUser := model.User{
		Id:          c.GetInt("id"),
		Username:    user.Username,
		Password:    user.Password,
		DisplayName: user.DisplayName,
		Token:       user.Token,
		Channel:     user.Channel,
	}

	if user.Password == "$I_LOVE_U" {
		user.Password = "" // rollback to what it should be
		cleanUser.Password = ""
	}
	updatePassword := user.Password != ""
	if err := cleanUser.Update(updatePassword); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}

func DeleteUser(c *gin.Context) {
	id, err := strconv.Atoi(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	originUser, err := model.GetUserById(id, false)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	myRole := c.GetInt("role")
	if myRole <= originUser.Role {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无权删除同权限等级或更高权限等级的用户",
		})
		return
	}
	channel.TokenStoreRemoveUser(originUser)
	err = model.DeleteUserById(id)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": true,
			"message": "",
		})
		return
	}
}

func DeleteSelf(c *gin.Context) {
	id := c.GetInt("id")
	user := model.User{Id: id}
	err := user.FillUserById()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	channel.TokenStoreRemoveUser(&user)
	err = model.DeleteUserById(id)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}

func CreateUser(c *gin.Context) {
	var user model.User
	err := json.NewDecoder(c.Request.Body).Decode(&user)
	if err != nil || user.Username == "" || user.Password == "" {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无效的参数",
		})
		return
	}
	if user.DisplayName == "" {
		user.DisplayName = user.Username
	}
	myRole := c.GetInt("role")
	if user.Role >= myRole {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无法创建权限大于等于自己的用户",
		})
		return
	}
	// Even for admin users, we cannot fully trust them!
	cleanUser := model.User{
		Username:    user.Username,
		Password:    user.Password,
		DisplayName: user.DisplayName,
	}
	if err := cleanUser.Insert(); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}

type ManageRequest struct {
	Username string `json:"username"`
	Action   string `json:"action"`
}

// ManageUser Only admin user can do this
func ManageUser(c *gin.Context) {
	var req ManageRequest
	err := json.NewDecoder(c.Request.Body).Decode(&req)

	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无效的参数",
		})
		return
	}
	user := model.User{
		Username: req.Username,
	}
	// Fill attributes
	model.DB.Where(&user).First(&user)
	if user.Id == 0 {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "用户不存在",
		})
		return
	}
	myRole := c.GetInt("role")
	if myRole <= user.Role && myRole != common.RoleRootUser {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "无权更新同权限等级或更高权限等级的用户信息",
		})
		return
	}
	switch req.Action {
	case "disable":
		if user.Status == common.UserStatusDisabled {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "该账户已经是封禁状态",
			})
			return
		}
		if user.Role == common.RoleRootUser {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "无法禁用超级管理员用户",
			})
			return
		}
		channel.TokenStoreRemoveUser(&user)
		user.Status = common.UserStatusDisabled
	case "enable":
		if user.Status == common.UserStatusEnabled {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "该账户已经是启用状态",
			})
			return
		}
		channel.TokenStoreAddUser(&user)
		user.Status = common.UserStatusEnabled
	case "delete":
		if user.Role == common.RoleRootUser {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "无法删除超级管理员用户",
			})
			return
		}
		if err := user.Delete(); err != nil {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": err.Error(),
			})
			return
		}
		channel.TokenStoreRemoveUser(&user)
	case "promote":
		if myRole != common.RoleRootUser {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "普通管理员用户无法提升其他用户为管理员",
			})
			return
		}
		if user.Role >= common.RoleAdminUser {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "该用户已经是管理员",
			})
			return
		}
		user.Role = common.RoleAdminUser
	case "demote":
		if user.Role == common.RoleRootUser {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "无法降级超级管理员用户",
			})
			return
		}
		if user.Role == common.RoleCommonUser {
			c.JSON(http.StatusOK, gin.H{
				"success": false,
				"message": "该用户已经是普通用户",
			})
			return
		}
		user.Role = common.RoleCommonUser
	case "allow_send_email_to_others":
		user.SendEmailToOthers = common.SendEmailToOthersAllowed
	case "disallow_send_email_to_others":
		user.SendEmailToOthers = common.SendEmailToOthersDisallowed
	case "allow_save_message_to_database":
		user.SaveMessageToDatabase = common.SaveMessageToDatabaseAllowed
	case "disallow_save_message_to_database":
		user.SaveMessageToDatabase = common.SaveMessageToDatabaseDisallowed
	}

	if err := user.Update(false); err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	clearUser := model.User{
		Role:                  user.Role,
		Status:                user.Status,
		SendEmailToOthers:     user.SendEmailToOthers,
		SaveMessageToDatabase: user.SaveMessageToDatabase,
	}
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
		"data":    clearUser,
	})
	return
}

func EmailBind(c *gin.Context) {
	email := c.Query("email")
	code := c.Query("code")
	if !common.VerifyCodeWithKey(email, code, common.EmailVerificationPurpose) {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": "验证码错误或已过期",
		})
		return
	}
	id := c.GetInt("id")
	user := model.User{
		Id: id,
	}
	err := user.FillUserById()
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	user.Email = email
	// no need to check if this email already taken, because we have used verification code to check it
	err = user.Update(false)
	if err != nil {
		c.JSON(http.StatusOK, gin.H{
			"success": false,
			"message": err.Error(),
		})
		return
	}
	// create email channel for this user
	emailChannel := model.Channel{
		Type:        model.TypeEmail,
		UserId:      user.Id,
		Name:        "email",
		Description: "系统自动创建",
		Status:      common.ChannelStatusEnabled,
		CreatedTime: common.GetTimestamp(),
	}
	_ = emailChannel.Insert()
	c.JSON(http.StatusOK, gin.H{
		"success": true,
		"message": "",
	})
	return
}