package user

import (
	"context"
	"strings"
	"time"

	"github.com/gin-contrib/sessions"
	"github.com/gin-gonic/gin"
	"github.com/linux-do/credit/internal/apps/oauth"
	"github.com/linux-do/credit/internal/common"
	"github.com/linux-do/credit/internal/common/bind"
	"github.com/linux-do/credit/internal/common/response"
	"github.com/linux-do/credit/internal/db"
	"github.com/linux-do/credit/internal/model"
	"github.com/linux-do/credit/internal/util"
)

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

type registerRequest struct {
	Username    string `json:"username"`
	Password    string `json:"password"`
	Nickname    string `json:"nickname"`
	DisplayName string `json:"display_name"`
}

func isPasswordLoginEnabled() bool {
	enabled, err := model.GetBoolByKey(context.Background(), model.ConfigKeyPasswordLoginEnabled)
	if err != nil {
		return true
	}
	return enabled
}

func isPasswordRegisterEnabled() bool {
	enabled, err := model.GetBoolByKey(context.Background(), model.ConfigKeyPasswordRegisterEnabled)
	if err != nil {
		return true
	}
	return enabled
}

func isRegistrationEnabled() bool {
	enabled, err := model.GetBoolByKey(context.Background(), model.ConfigKeyRegistrationEnabled)
	if err != nil {
		return true
	}
	return enabled
}

func setLoginSession(c *gin.Context, user *model.User) error {
	session := sessions.Default(c)
	session.Set(oauth.UserIDKey, user.ID)
	session.Set(oauth.UserNameKey, user.Username)
	if err := session.Save(); err != nil {
		return err
	}
	return nil
}

// Login 用户密码登录
// @Summary 用户密码登录
// @Description 使用用户名和密码登录，登录成功后建立 Session。若管理员已关闭密码登录功能则返回错误。
// @Tags user
// @Accept json
// @Produce json
// @Param request body user.loginRequest true "登录请求参数"
// @Success 200 {object} util.ResponseAny{data=oauth.BasicUserInfo} "登录成功，返回用户信息"
// @Failure 400 {object} util.ResponseAny "用户名或密码错误、帐号已禁用等"
// @Failure 500 {object} util.ResponseAny "服务内部错误"
// @Router /api/v1/user/login [post]
func Login(c *gin.Context) {
	if !isPasswordLoginEnabled() {
		response.RespondFailure(c, "管理员关闭了密码登录")
		return
	}
	var req loginRequest
	if !bind.JSON(c, &req) {
		return
	}
	req.Username = strings.TrimSpace(req.Username)
	if req.Username == "" || req.Password == "" {
		response.RespondFailure(c, "无效的参数")
		return
	}

	var user model.User
	ctx := c.Request.Context()
	if err := db.DB(ctx).Where("username = ?", req.Username).First(&user).Error; err != nil {
		response.RespondFailure(c, "用户名或密码错误")
		return
	}
	if !user.IsActive {
		response.RespondFailure(c, common.BannedAccount)
		return
	}
	if !user.CheckPassword(req.Password) {
		response.RespondFailure(c, "用户名或密码错误")
		return
	}

	user.LastLoginAt = time.Now()
	if err := db.DB(ctx).Model(&user).Update("last_login_at", user.LastLoginAt).Error; err != nil {
		response.RespondFailure(c, err.Error())
		return
	}
	if err := setLoginSession(c, &user); err != nil {
		response.RespondFailure(c, "无法保存会话信息，请重试")
		return
	}

	response.RespondSuccess(c, oauth.BuildBasicUserInfo(&user))
}

// Register 用户注册
// @Summary 用户注册
// @Description 使用用户名和密码注册新账号，注册成功后自动登录并建立 Session。密码长度不能少于 8 位。
// @Tags user
// @Accept json
// @Produce json
// @Param request body user.registerRequest true "注册请求参数"
// @Success 200 {object} util.ResponseAny{data=oauth.BasicUserInfo} "注册并登录成功，返回用户信息"
// @Failure 400 {object} util.ResponseAny "参数错误、用户名已存在或注册已关闭"
// @Failure 500 {object} util.ResponseAny "服务内部错误"
// @Router /api/v1/user/register [post]
func Register(c *gin.Context) {
	if !isRegistrationEnabled() || !isPasswordRegisterEnabled() {
		response.RespondFailure(c, "管理员关闭了注册")
		return
	}

	var req registerRequest
	if !bind.JSON(c, &req) {
		return
	}

	req.Username = strings.TrimSpace(req.Username)
	req.Password = strings.TrimSpace(req.Password)
	req.Nickname = strings.TrimSpace(req.Nickname)
	req.DisplayName = strings.TrimSpace(req.DisplayName)

	if req.Username == "" || req.Password == "" {
		response.RespondFailure(c, "无效的参数")
		return
	}
	if len(req.Password) < 8 {
		response.RespondFailure(c, "密码长度不能少于 8 位")
		return
	}

	ctx := c.Request.Context()
	var count int64
	if err := db.DB(ctx).Model(&model.User{}).Where("username = ?", req.Username).Count(&count).Error; err != nil {
		response.RespondFailure(c, err.Error())
		return
	}
	if count > 0 {
		response.RespondFailure(c, "用户名已存在")
		return
	}

	user := model.User{
		Username:    req.Username,
		Nickname:    req.Nickname,
		AvatarUrl:   "",
		TrustLevel:  model.TrustLevelNewUser,
		PayScore:    0,
		SignKey:     util.GenerateUniqueIDSimple(),
		IsActive:    true,
		IsAdmin:     false,
		LastLoginAt: time.Now(),
	}
	if user.Nickname == "" {
		user.Nickname = req.DisplayName
	}
	if user.Nickname == "" {
		user.Nickname = req.Username
	}
	if err := user.SetPassword(req.Password); err != nil {
		response.RespondFailure(c, err.Error())
		return
	}

	if err := db.DB(ctx).Create(&user).Error; err != nil {
		response.RespondFailure(c, err.Error())
		return
	}

	if err := setLoginSession(c, &user); err != nil {
		response.RespondFailure(c, "无法保存会话信息，请重试")
		return
	}

	response.RespondSuccess(c, oauth.BuildBasicUserInfo(&user))
}

// Logout 用户退出登录
// @Summary 用户退出登录
// @Description 清除用户登录 Session，完成退出
// @Tags user
// @Produce json
// @Security SessionCookie
// @Success 200 {object} util.ResponseAny{data=string} "退出成功"
// @Failure 500 {object} util.ResponseAny "Session 清除失败"
// @Router /api/v1/user/logout [get]
func Logout(c *gin.Context) {
	session := sessions.Default(c)
	session.Options(util.GetSessionOptions(-1))
	session.Clear()
	if err := session.Save(); err != nil {
		response.RespondFailure(c, err.Error())
		return
	}
	response.RespondSuccessMessage(c, "")
}