package ckwk

import (
	"ckwk/internal/conf"
	"ckwk/pkg/common"
	"ckwk/pkg/log"
	"ckwk/pkg/request"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"regexp"
	"strconv"
	"strings"
	"sync"

	"github.com/antchfx/htmlquery"
	"go.uber.org/zap"
	"resty.dev/v3"
)

var (
	ErrLoginTimeout   = errors.New("登录超时,请重新登录")
	ErrSessionRemoved = errors.New("session_manager 已删除失效会话")
	ErrReloginSkipped = errors.New("当前会话缺少账号密码，无法自动重新登录")
)

const maxAutoReloginRetries = 3

type WK struct {
	Username string `json:"username"`
	Password string `json:"password"`
	Host     string `json:"host"`
	Req      *resty.Client

	Cookies []*http.Cookie

	LoginRegexp    *regexp.Regexp
	CourseIDRegexp *regexp.Regexp
	TimeRegexp     *regexp.Regexp

	authMu         sync.Mutex
	sessionID      string
	sessionManager *SessionManager
}

func NewWK(username, password, host string, cookies []*http.Cookie) *WK {
	hasAuth := (username != "" && password != "") || len(cookies) > 0
	if host == "" || !hasAuth {
		return nil
	}

	reqCfg := &request.Config{
		UserAgent: "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/140.0.0.0 Safari/537.36 Edg/140.0.0.0",
		VerifySSL: true,
		Debug:     conf.IsRuntimeDebugEnabled(),
	}
	if conf.IsRuntimeDebugEnabled() {
		reqCfg.Proxy = conf.DebugProxy
		reqCfg.VerifySSL = !conf.DebugSkipSSLVerify
	}

	req := request.NewClient(reqCfg)
	if len(cookies) > 0 {
		req.SetCookies(cookies)
	}

	wk := &WK{
		Username: username,
		Password: password,
		Host:     host,
		Req:      req,
		Cookies:  cookies,

		LoginRegexp:    regexp.MustCompile("var data =(.*?);"),
		CourseIDRegexp: regexp.MustCompile(`\?courseId=(\d+)`),
		TimeRegexp:     regexp.MustCompile(`\d{4}-\d{2}-\d{2}`),
	}

	return wk
}

func (wk *WK) bindSession(sm *SessionManager, sessionID string) {
	wk.sessionManager = sm
	wk.sessionID = sessionID
}

func (wk *WK) prepareRequestClient() {
	if wk == nil || wk.Req == nil {
		return
	}

	cfg := &request.Config{
		UserAgent: request.DefaultUserAgent,
		VerifySSL: true,
		Debug:     conf.IsRuntimeDebugEnabled(),
	}
	if conf.IsRuntimeDebugEnabled() {
		cfg.Proxy = conf.DebugProxy
		cfg.VerifySSL = !conf.DebugSkipSSLVerify
	}

	request.ApplyConfig(wk.Req, cfg)
	if len(wk.Cookies) > 0 {
		wk.Req.SetCookies(wk.Cookies)
	}
}

func (wk *WK) newRequest() *resty.Request {
	wk.prepareRequestClient()
	return wk.Req.R()
}

// Cookies: returns cookies
func (wk *WK) Cookie() []*http.Cookie {
	return wk.Cookies
}

// SetCookies: returns cookies
func (wk *WK) SetCookies(cs []*http.Cookie) {
	wk.Cookies = cs
	wk.Req.SetCookies(cs)
}

// Code: Get Verify Code
func (wk *WK) Code() (string, error) {
	resp, err := wk.newRequest().
		SetQueryParam("r", fmt.Sprint(common.RandFloat64())).
		Get(fmt.Sprintf("https://%s/service/code", wk.Host))

	if err != nil {
		return "", fmt.Errorf("获取验证码失败: %w", err)
	}

	if resp.StatusCode() != 200 {
		return "", fmt.Errorf("获取验证码失败: code: %d", resp.StatusCode())
	}
	var result CodeResp
	_, err = wk.newRequest().
		SetFormData(map[string]string{
			"image":       base64.StdEncoding.EncodeToString(resp.Bytes()),
			"probability": "false",
			"png_fix":     "false",
		}).
		SetResult(&result).
		Post(fmt.Sprintf("%s/ocr", conf.DdddOCR))
	if err != nil {
		return "", fmt.Errorf("获取验证码验证结果失败: %w", err)
	}
	if result.Code != 200 {
		return "", fmt.Errorf("ocr 失败: code: %d, message: %s", result.Code, result.Message)
	}
	return result.Data, nil
}

// Login: Login WebSite
func (wk *WK) Login() (bool, error) {
	yzm := ""
	for i := 1; i <= 3; i++ {
		yzm, _ = wk.Code()
		if yzm != "" {
			break
		}
		log.Warnf("第 %d 次获取验证码失败, 正在重试...\n", i)
	}
	if yzm == "" {
		return false, fmt.Errorf("以达到最大重试次数，验证码获取失败，登录终止。")
	}

	resp, err := wk.newRequest().
		SetFormData(map[string]string{
			"username": wk.Username,
			"password": wk.Password,
			"code":     yzm,
			"redirect": "",
		}).
		Post(fmt.Sprintf("https://%s/user/login", wk.Host))

	if err != nil {
		return false, fmt.Errorf("请求登录失败: %w", err)
	}
	result, err := wk.parseLoginResp(resp.Bytes())
	if err != nil {
		return false, err
	}

	if !result.Status {
		return false, fmt.Errorf("登录失败: %s", loginErrorMessage(result))
	}
	wk.SetCookies(resp.Cookies())
	log.Info("登录成功", zap.Any("cookies", wk.Req.Cookies()))
	return true, nil
}

func (wk *WK) parseLoginResp(body []byte) (LoginResp, error) {
	var result LoginResp
	if len(body) == 0 {
		return result, fmt.Errorf("登录响应为空")
	}

	matchs := wk.LoginRegexp.FindStringSubmatch(string(body))
	if len(matchs) > 1 {
		if err := json.Unmarshal([]byte(strings.TrimSpace(matchs[1])), &result); err != nil {
			return result, fmt.Errorf("解析登录响应失败: %w", err)
		}
		return result, nil
	}

	if err := json.Unmarshal(body, &result); err != nil {
		return result, fmt.Errorf("解析登录响应失败: %w", err)
	}

	return result, nil
}

func loginErrorMessage(result LoginResp) string {
	if msg := strings.TrimSpace(result.FormError.Code); msg != "" {
		return msg
	}
	if msg := strings.TrimSpace(result.Msg); msg != "" {
		return msg
	}
	return "未知错误"
}

// CourseParse: 课程解析
func (wk *WK) CourseParse(content string) ([]Course, error) {
	courses := make([]Course, 0)
	doc, err := htmlquery.Parse(strings.NewReader(content))
	if err != nil {
		return courses, fmt.Errorf("解析 HTML 失败: %w", err)
	}

	itemsNode := htmlquery.Find(doc, `//div[@class="user-course"]/div[@class="item"]`)
	if len(itemsNode) < 1 {
		return courses, nil
		// return courses, fmt.Errorf("未解析到课程")
	}

	for _, node := range itemsNode {
		aNode := htmlquery.FindOne(node, `.//div[@class="name"]/a`)
		if aNode == nil {
			continue
		}
		href := htmlquery.SelectAttr(aNode, "href")

		match := wk.CourseIDRegexp.FindStringSubmatch(href)
		var id int
		if len(match) > 1 {
			idVal, err := strconv.Atoi(match[1])
			if err == nil {
				id = idVal
			} else {
				log.Warn("ID 转换失败", zap.Error(err))
			}
		}

		tagsNode := htmlquery.FindOne(node, `.//div[@class="tags"]/span`)
		progressNode := htmlquery.FindOne(node, `.//div[@class="progress"]/div[@class="txt"]`)

		timeNode := htmlquery.FindOne(node, `.//div[@class="time"]`)
		var startTime, stopTime string
		if timeNode != nil {
			fullText := htmlquery.InnerText(timeNode)
			dates := wk.TimeRegexp.FindAllString(fullText, -1)

			if len(dates) >= 2 {
				startTime = dates[0]
				stopTime = dates[1]
			}
		}

		var credit float32
		creditNode := htmlquery.FindOne(node, `.//div[@class="note"]/div[@class="number"]/span`)
		creditStr := strings.TrimSpace(htmlquery.InnerText(creditNode))
		creditVal, err := strconv.ParseFloat(creditStr, 32)
		if err == nil {
			credit = float32(creditVal)
		} else {
			log.Warn("课程学分转换失败", zap.Error(err))
		}

		typeNode := htmlquery.FindOne(node, `.//div[@class="note"]/div[@class="kind"]/span`)

		course := Course{
			ID:        id,
			Name:      htmlquery.InnerText(aNode),
			Teacher:   htmlquery.InnerText(tagsNode),
			Progress:  htmlquery.InnerText(progressNode),
			StartTime: startTime,
			StopTime:  stopTime,
			Credit:    credit,
			Type:      htmlquery.InnerText(typeNode),
		}
		courses = append(courses, course)
	}
	return courses, nil
}

// CourseGet: 课程获取
func (wk *WK) CourseGet(kind CourseKind) ([]Course, error) {
	var courses []Course
	resp, err := wk.newRequest().
		SetQueryParam("kind", string(kind)).
		Get(fmt.Sprintf("https://%s/user/index", wk.Host))
	if err != nil {
		return courses, fmt.Errorf("获取课程失败: %w", err)
	}
	courses, err = wk.CourseParse(string(resp.Bytes()))
	if err != nil {
		return courses, fmt.Errorf("解析课程失败: %w", err)
	}

	return courses, nil
}

// UserParse: 用户信息解析
func (wk *WK) UserInfoParse(content string) (User, error) {
	var user User

	doc, err := htmlquery.Parse(strings.NewReader(content))
	if err != nil {
		return user, fmt.Errorf("解析用户信息失败: %w", err)
	}

	userInfoNode := htmlquery.FindOne(doc, `//div[@class="useredata-form"]`)
	if userInfoNode == nil {
		return user, fmt.Errorf("未解析到用户信息")
	}
	nameNode := htmlquery.FindOne(userInfoNode, `.//div[@class="item"][1]/div[@class="txt"]/text()`)
	if nameNode != nil {
		user.Name = strings.TrimSpace(htmlquery.InnerText(nameNode))
	}
	idNode := htmlquery.FindOne(userInfoNode, `.//div[@class="item"][2]/div[@class="txt"]`)
	if idNode != nil {
		user.ID = strings.TrimSpace(htmlquery.InnerText(idNode))
	}
	deptNode := htmlquery.FindOne(userInfoNode, `.//div[@class="item"][3]/div[@class="txt"]`)
	if deptNode != nil {
		user.Dept = strings.TrimSpace(htmlquery.InnerText(deptNode))
	}
	classNode := htmlquery.FindOne(userInfoNode, `.//div[@class="item"][4]/div[@class="txt"]`)
	if classNode != nil {
		user.Class = strings.TrimSpace(htmlquery.InnerText(classNode))
	}
	genderNode := htmlquery.FindOne(userInfoNode, `.//select[@id="gender"]/option[@selected="selected"]`)
	if genderNode != nil {
		user.Gender = htmlquery.SelectAttr(genderNode, "value")
	}

	return user, nil
}

// UserGet: 用户信息获取
func (wk *WK) UserInfoGet() (User, error) {
	var user User
	resp, err := wk.newRequest().
		Get(fmt.Sprintf("https://%s/user/member", wk.Host))
	if err != nil {
		return user, fmt.Errorf("获取用户信息页面失败: %w", err)
	}
	user, err = wk.UserInfoParse(string(resp.Bytes()))
	if err != nil {
		return user, err
	}

	wk.Username = user.ID

	return user, nil
}

// Online: 保持账号状态
func (wk *WK) performOnline() (bool, error) {
	resp, err := wk.newRequest().
		SetHeaders(map[string]string{
			"x-requested-with": "XMLHttpRequest",
			"Accept":           "application/json, text/javascript, */*; q=0.01",
			"Accept-Encoding":  "gzip, deflate, br, zstd",
		}).
		Post(fmt.Sprintf("https://%s/user/online", wk.Host))
	if err != nil {
		return false, fmt.Errorf("保持账号状态失败: %w", err)
	}
	if isLoginTimeoutBody(resp.Bytes()) {
		return false, fmt.Errorf("保持账号状态失败: %w", ErrLoginTimeout)
	}
	log.Info("保持账号状态", zap.Any("resp", string(resp.Bytes())))
	return true, nil
}

func (wk *WK) Online() (bool, error) {
	return withAutoRelogin(wk, "保持账号状态", wk.performOnline)
}

// Study: 学习
func (wk *WK) performStudy(nodeID, studyID, studyTime string, status StudyStatus) (*StudyResp, error) {
	var data map[string]string
	switch status {
	case StudyStart:
		yzm := ""
		for i := 1; i <= 3; i++ {
			yzm, _ = wk.Code()
			if yzm != "" {
				break
			}
			log.Warnf("第 %d 次获取验证码失败, 正在重试...\n", i)
		}
		if yzm == "" {
			return nil, fmt.Errorf("以达到最大重试次数，验证码获取失败，登录终止。")
		}
		data = map[string]string{
			"nodeId":    nodeID,
			"studyId":   "0",
			"studyTime": "1",
			"code":      yzm,
		}
	case Study:
		data = map[string]string{
			"nodeId":    nodeID,
			"studyId":   studyID,
			"studyTime": studyTime,
		}
	case StudyOver:
		data = map[string]string{
			"nodeId":    nodeID,
			"studyId":   studyID,
			"studyTime": studyTime,
			"close":     "1",
		}
	default:
		return nil, fmt.Errorf("传入的学习状态不匹配")
	}
	resp, err := wk.newRequest().
		SetHeaders(map[string]string{
			"x-requested-with": "XMLHttpRequest",
			"Accept":           "application/json, text/javascript, */*; q=0.01",
			"Accept-Encoding":  "gzip, deflate, br, zstd",
		}).
		SetFormData(data).
		Post(fmt.Sprintf("https://%s/user/node/study", wk.Host))

	if err != nil {
		return nil, fmt.Errorf("进行学习失败: %w", err)
	}
	if isLoginTimeoutBody(resp.Bytes()) {
		return nil, fmt.Errorf("进行学习失败: %w", ErrLoginTimeout)
	}

	var result StudyResp
	if err := json.Unmarshal(resp.Bytes(), &result); err != nil {
		return nil, fmt.Errorf("解析响应失败: %w", err)
	}

	log.Info("学习响应", zap.Any("resp", result))
	return &result, nil
}

func (wk *WK) Study(nodeID, studyID, studyTime string, status StudyStatus) (*StudyResp, error) {
	return withAutoRelogin(wk, "进行学习", func() (*StudyResp, error) {
		return wk.performStudy(nodeID, studyID, studyTime, status)
	})
}

// GetStudyList: 获取学习记录
func (wk *WK) GetStudyList(courseID, page string) (*AllRecordResp[StudyList], error) {
	return GetRecords[StudyList](wk, RecordStudy, courseID, page)
}

// GetExamList: 获取作业记录
// todo
func (wk *WK) GetWorkList(courseID, page string) (*AllRecordResp[ExamList], error) {
	return GetRecords[ExamList](wk, RecordStudy, courseID, page)
}

// GetExamList: 获取考试记录
func (wk *WK) GetExamList(courseID, page string) (*AllRecordResp[ExamList], error) {
	return GetRecords[ExamList](wk, RecordExam, courseID, page)
}

// GetExamList: 获取讨论记录
// todo
func (wk *WK) GetDiscussList(courseID, page string) (*AllRecordResp[ExamList], error) {
	return GetRecords[ExamList](wk, RecordStudy, courseID, page)
}

func isLoginTimeoutBody(body []byte) bool {
	if len(body) == 0 {
		return false
	}

	var payload struct {
		Offline int    `json:"offline"`
		Status  bool   `json:"status"`
		Msg     string `json:"msg"`
	}
	if err := json.Unmarshal(body, &payload); err != nil {
		return false
	}

	return payload.Offline == 1 && !payload.Status && strings.Contains(payload.Msg, "登录超时")
}

func (wk *WK) reloginForExpiredSession(action string, attempt int) error {
	wk.authMu.Lock()
	defer wk.authMu.Unlock()

	if strings.TrimSpace(wk.Username) == "" || strings.TrimSpace(wk.Password) == "" {
		return fmt.Errorf("%w: 检测到 %s 登录超时", ErrReloginSkipped, action)
	}

	log.Warn("检测到登录超时，开始自动重新登录",
		zap.String("action", action),
		zap.String("host", wk.Host),
		zap.String("username", wk.Username),
		zap.Int("attempt", attempt),
		zap.Int("maxAttempts", maxAutoReloginRetries),
	)

	ok, err := wk.Login()
	if err != nil {
		return fmt.Errorf("第 %d 次自动重新登录失败: %w", attempt, err)
	}
	if !ok {
		return fmt.Errorf("第 %d 次自动重新登录失败", attempt)
	}

	log.Info("自动重新登录成功",
		zap.String("action", action),
		zap.String("host", wk.Host),
		zap.String("username", wk.Username),
		zap.Int("attempt", attempt),
	)
	return nil
}

func (wk *WK) removeBoundSession(action string, cause error) {
	if wk == nil || wk.sessionManager == nil || wk.sessionID == "" {
		return
	}

	log.Warn("自动重新登录失败，删除失效会话",
		zap.String("action", action),
		zap.String("session_id", wk.sessionID),
		zap.String("host", wk.Host),
		zap.String("username", wk.Username),
		zap.Error(cause),
	)
	wk.sessionManager.Del(wk.sessionID)
}

func withAutoRelogin[T any](wk *WK, action string, fn func() (T, error)) (T, error) {
	result, err := fn()
	if !errors.Is(err, ErrLoginTimeout) {
		return result, err
	}

	lastErr := err
	for attempt := 1; attempt <= maxAutoReloginRetries; attempt++ {
		reloginErr := wk.reloginForExpiredSession(action, attempt)
		if reloginErr != nil {
			lastErr = reloginErr
			if errors.Is(reloginErr, ErrReloginSkipped) {
				break
			}
			continue
		}

		result, err = fn()
		if !errors.Is(err, ErrLoginTimeout) {
			return result, err
		}
		lastErr = err
	}

	wk.removeBoundSession(action, lastErr)

	var zero T
	if lastErr == nil {
		lastErr = ErrLoginTimeout
	}
	return zero, fmt.Errorf("%w: %s 自动重新登录 %d 次后仍未恢复: %v", ErrSessionRemoved, action, maxAutoReloginRetries, lastErr)
}