package web

import (
	"errors"
	"fmt"
	"net/http"
	"sort"
	"strconv"
	"strings"
	"time"

	"daili/internal/domain"
	"daili/internal/store"
)

type customersData struct {
	List          []store.Customer
	Pager         Pager
	Q             string
	Total         int
	PackageCount  int
	NoPackages    bool
	ShowArchived  bool
	ArchivedCount int
}

func (s *Server) handleCustomers(w http.ResponseWriter, r *http.Request) {
	today := domain.Today()
	warn := s.warnDays()
	q := r.URL.Query().Get("q")
	pageNo := s.queryInt(r, "page", 1)
	if pageNo < 1 {
		pageNo = 1
	}
	showArchived := r.URL.Query().Get("archived") == "1"
	list, total, err := s.db.ListCustomers(q, pageSize, (pageNo-1)*pageSize, domain.Date(today), warn, showArchived)
	if err != nil {
		http.Error(w, "读取客户失败", http.StatusInternalServerError)
		return
	}
	pager := newPager(r, pageNo, pageSize, total)
	if pager.Page != pageNo {
		list, total, err = s.db.ListCustomers(q, pageSize, (pager.Page-1)*pageSize, domain.Date(today), warn, showArchived)
		if err != nil {
			http.Error(w, "读取客户失败", http.StatusInternalServerError)
			return
		}
	}
	pkgs, _ := s.db.ListPackages(false)
	archivedN, _ := s.db.CountArchivedCustomers()
	data := &customersData{List: list, Pager: pager, Q: q, Total: total, PackageCount: len(pkgs), NoPackages: len(pkgs) == 0,
		ShowArchived: showArchived, ArchivedCount: archivedN}
	p := s.newPage(r, "客户", "customers")
	p.D = data
	s.render(w, r, "customers", p)
}

type customerFormData struct {
	Customer *store.Customer
	IsNew    bool
	Users    []store.User
}

func (s *Server) handleCustomerNewPage(w http.ResponseWriter, r *http.Request) {
	p := s.newPage(r, "新建客户", "customers")
	users, _ := s.db.ActiveUsers()
	p.D = &customerFormData{Customer: &store.Customer{}, IsNew: true, Users: users}
	s.render(w, r, "customer_form", p)
}

func (s *Server) readCustomerForm(r *http.Request) *store.Customer {
	return &store.Customer{
		Tail:       strings.TrimSpace(r.PostFormValue("tail")),
		Name:       strings.TrimSpace(r.PostFormValue("name")),
		GameName:   strings.TrimSpace(r.PostFormValue("game_name")),
		GameServer: strings.TrimSpace(r.PostFormValue("game_server")),
		Contact:    strings.TrimSpace(r.PostFormValue("contact")),
		Tags:       normalizeTags(r.PostFormValue("tags")),
		Source:     strings.TrimSpace(r.PostFormValue("source")),
		Note:       strings.TrimSpace(r.PostFormValue("note")),
		AssigneeID: int64(s.formInt(r, "assignee_id", 0)),
	}
}

func normalizeTags(v string) string {
	parts := strings.FieldsFunc(v, func(r rune) bool { return r == ',' || r == '，' || r == ' ' || r == ';' || r == '；' })
	seen := map[string]bool{}
	out := []string{}
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p == "" || seen[p] {
			continue
		}
		seen[p] = true
		out = append(out, p)
	}
	return strings.Join(out, ",")
}

func validateCustomer(c *store.Customer) string {
	if c.Tail == "" {
		return "手机尾号不能为空"
	}
	if len([]rune(c.Tail)) > 8 {
		return "手机尾号最长 8 位"
	}
	if c.Name == "" {
		return "客户名不能为空"
	}
	if len([]rune(c.Name)) > 32 {
		return "客户名最长 32 字"
	}
	return ""
}

func (s *Server) handleCustomerCreate(w http.ResponseWriter, r *http.Request) {
	c := s.readCustomerForm(r)
	p := s.newPage(r, "新建客户", "customers")
	if msg := validateCustomer(c); msg != "" {
		users, _ := s.db.ActiveUsers()
		p.D = &customerFormData{Customer: c, IsNew: true, Users: users}
		s.fail(w, r, "customer_form", msg, p)
		return
	}
	id, err := s.db.CreateCustomer(c)
	if err != nil {
		msg := "创建失败：" + err.Error()
		if errors.Is(err, store.ErrDuplicate) {
			msg = "该「尾号 + 姓名」的客户已存在，请直接搜索后追加订阅"
		}
		users, _ := s.db.ActiveUsers()
		p.D = &customerFormData{Customer: c, IsNew: true, Users: users}
		s.fail(w, r, "customer_form", msg, p)
		return
	}
	s.logOp(r, "新建客户", "customer", id, "新建客户 "+c.Tail+" "+c.Name)
	s.redirect(w, r, "/customers/"+itoa(id), "客户已创建，接着为他添加订阅")
}

func (s *Server) handleCustomerEditPage(w http.ResponseWriter, r *http.Request) {
	c, err := s.db.Customer(pathID(r))
	if err != nil {
		http.NotFound(w, r)
		return
	}
	p := s.newPage(r, "编辑客户", "customers")
	p.D = &customerFormData{Customer: c, IsNew: false}
	s.render(w, r, "customer_form", p)
}

func (s *Server) handleCustomerUpdate(w http.ResponseWriter, r *http.Request) {
	id := pathID(r)
	old, err := s.db.Customer(id)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	c := s.readCustomerForm(r)
	c.ID = id
	p := s.newPage(r, "编辑客户", "customers")
	if msg := validateCustomer(c); msg != "" {
		p.D = &customerFormData{Customer: c, IsNew: false}
		s.fail(w, r, "customer_form", msg, p)
		return
	}
	if err := s.db.UpdateCustomer(c); err != nil {
		msg := "保存失败：" + err.Error()
		if errors.Is(err, store.ErrDuplicate) {
			msg = "该「尾号 + 姓名」的客户已存在"
		}
		p.D = &customerFormData{Customer: c, IsNew: false}
		s.fail(w, r, "customer_form", msg, p)
		return
	}
	s.logOp(r, "编辑客户", "customer", id, "修改客户 "+c.Tail+" "+c.Name+"（原 "+old.Tail+" "+old.Name+"）")
	s.redirect(w, r, "/customers/"+itoa(id), "客户资料已保存")
}

// CheckinRow 是打卡历史的展示行。
type CheckinRow struct {
	store.Checkin
	SubName  string
	SubColor string
}

type customerDetailData struct {
	Customer    *store.Customer
	Subs        []SubView
	Adjustments []store.Adjustment
	AdjSubName  map[int64]string
	AdjSubColor map[int64]string
	Checkins    []CheckinRow
	Packages    []store.Package
	Users       []store.User
	CustCal     *custCal
	Timeline    *Timeline
	Extend      *ExtendPanel
	TotalRemain string
}

// custCalDay 客户月历的一格。
type custCalDay struct {
	Date    string
	Day     int
	InMonth bool
	IsToday bool
	Count   int
	Done    int
	AllDone bool
}

// custCal 客户详情页的当月排单日历。
type custCal struct {
	Year, Month int
	Title       string
	Prev, Next  string
	Weekdays    []string
	Weeks       [][]custCalDay
	TaskDays    int
	TotalTasks  int
}

func (s *Server) buildCustomerCal(c *store.Customer, cm string, today time.Time) *custCal {
	y, m := today.Year(), int(today.Month())
	if t, err := time.Parse("2006-01", cm); err == nil {
		y, m = t.Year(), int(t.Month())
	}
	monthStart := domain.MonthStart(y, time.Month(m))
	monthEnd := domain.MonthEnd(y, time.Month(m))
	gridStart := domain.AddDays(monthStart, -domain.WeekdayIndex(monthStart))
	weeks := (domain.WeekdayIndex(monthStart) + monthEnd.Day() + 6) / 7

	subs, err := s.db.SubsByCustomer(c.ID)
	if err != nil {
		return nil
	}
	ids := make([]int64, 0, len(subs))
	for _, sub := range subs {
		ids = append(ids, sub.ID)
	}
	pauses, _ := s.db.PausesForSubs(ids)
	checkins, _ := s.db.CheckinsBetween(domain.Date(gridStart), domain.Date(domain.AddDays(gridStart, weeks*7-1)))
	warn := s.warnDays()
	list := make([]calSub, 0, len(subs))
	for _, sub := range subs {
		cs := calSub{sub: sub, pauses: pauses[sub.ID], eval: sub.Eval(today, warn)}
		if sub.EndDate != "" {
			cs.hasEnd = true
			cs.end = domain.ParseDateOr(sub.EndDate, today)
		}
		list = append(list, cs)
	}

	cal := &custCal{
		Year: y, Month: m,
		Title:    fmt.Sprintf("%d 年 %d 月", y, m),
		Weekdays: []string{"一", "二", "三", "四", "五", "六", "日"},
	}
	py, pm := y, m-1
	if pm < 1 {
		pm = 12
		py--
	}
	ny, nm := y, m+1
	if nm > 12 {
		nm = 1
		ny++
	}
	cal.Prev = fmt.Sprintf("/customers/%d?cm=%04d-%02d", c.ID, py, pm)
	cal.Next = fmt.Sprintf("/customers/%d?cm=%04d-%02d", c.ID, ny, nm)

	for wi := 0; wi < weeks; wi++ {
		week := make([]custCalDay, 0, 7)
		for di := 0; di < 7; di++ {
			d := domain.AddDays(gridStart, wi*7+di)
			ds := domain.Date(d)
			cell := custCalDay{Date: ds, Day: d.Day(), InMonth: d.Month() == time.Month(m), IsToday: ds == domain.Date(today)}
			for _, cs := range list {
				if !cs.covers(ds) {
					continue
				}
				cell.Count++
				if ci, ok := checkins[cs.sub.ID][ds]; ok && (ci.Status == "done" || ci.Status == "skipped") {
					cell.Done++
				}
			}
			if cell.Count > 0 {
				cell.AllDone = cell.Done >= cell.Count
				if cell.InMonth {
					cal.TaskDays++
					cal.TotalTasks += cell.Count
				}
			}
			week = append(week, cell)
		}
		cal.Weeks = append(cal.Weeks, week)
	}
	return cal
}

func (s *Server) handleCustomerDetail(w http.ResponseWriter, r *http.Request) {
	id := pathID(r)
	c, err := s.db.Customer(id)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	today := domain.Today()
	warn := s.warnDays()

	subs, err := s.db.SubsByCustomer(id)
	if err != nil {
		http.Error(w, "读取订阅失败", http.StatusInternalServerError)
		return
	}
	pkgs, _ := s.db.ListPackages(false)
	ids := make([]int64, 0, len(subs))
	subByID := map[int64]store.Subscription{}
	for _, sub := range subs {
		ids = append(ids, sub.ID)
		subByID[sub.ID] = sub
	}
	pauses, _ := s.db.PausesForSubs(ids)

	users, _ := s.db.ActiveUsers()
	data := &customerDetailData{
		Users:       users,
		CustCal:     s.buildCustomerCal(c, r.URL.Query().Get("cm"), today),
		Customer:    c,
		Subs:        subViews(subs, today, warn),
		Packages:    pkgs,
		Timeline:    buildTimeline(subs, pauses, today),
		AdjSubName:  map[int64]string{},
		AdjSubColor: map[int64]string{},
	}
	for _, sub := range subs {
		data.AdjSubName[sub.ID] = sub.PackageName
		data.AdjSubColor[sub.ID] = sub.PackageColor
		adj, err := s.db.AdjustmentsBySub(sub.ID)
		if err == nil {
			data.Adjustments = append(data.Adjustments, adj...)
		}
		if ci, err := s.db.CheckinsForSub(sub.ID, 30); err == nil {
			for _, one := range ci {
				data.Checkins = append(data.Checkins, CheckinRow{Checkin: one, SubName: sub.PackageName, SubColor: sub.PackageColor})
			}
		}
	}
	// 按时间排序（新→旧）
	sortAdjustments(data.Adjustments)
	sortCheckins(data.Checkins)

	if eid := s.queryInt(r, "extend", 0); eid > 0 {
		if sub, ok := subByID[int64(eid)]; ok {
			if pkg, err := s.db.Package(sub.PackageID); err == nil {
				back := r.URL.Path + "?" + r.URL.RawQuery
				data.Extend = buildExtendPanel(&sub, pkg, today, back, warn)
			}
		}
	}

	p := s.newPage(r, c.Tail+" "+c.Name, "customers")
	p.D = data
	s.render(w, r, "customer_detail", p)
}

// handleCustomerArchive 停用客户：默认从列表、日历、大屏隐藏，订阅保留。
func (s *Server) handleCustomerArchive(w http.ResponseWriter, r *http.Request) {
	id := pathID(r)
	c, err := s.db.Customer(id)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	if err := s.db.SetCustomerArchived(id, true); err != nil {
		s.redirect(w, r, "/customers/"+itoa(id), "停用失败："+err.Error())
		return
	}
	s.logOp(r, "停用客户", "customer", id, c.Tail+" "+c.Name+"（订阅保留，不再上日历）")
	s.redirect(w, r, "/customers", "已停用客户 "+c.Tail+" "+c.Name+"，可在「已停用」里恢复")
}

// handleCustomerRestore 恢复客户，订单一并回到日历。
func (s *Server) handleCustomerRestore(w http.ResponseWriter, r *http.Request) {
	id := pathID(r)
	c, err := s.db.Customer(id)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	if err := s.db.SetCustomerArchived(id, false); err != nil {
		s.redirect(w, r, "/customers/"+itoa(id), "恢复失败："+err.Error())
		return
	}
	s.logOp(r, "恢复客户", "customer", id, c.Tail+" "+c.Name)
	s.redirect(w, r, "/customers/"+itoa(id), "已恢复客户 "+c.Tail+" "+c.Name)
}

// handleCustomerDelete 彻底删除客户及其订阅/打卡/追加记录（外键级联）。
func (s *Server) handleCustomerDelete(w http.ResponseWriter, r *http.Request) {
	id := pathID(r)
	c, err := s.db.Customer(id)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	if r.PostFormValue("confirm") != "delete" {
		s.redirect(w, r, "/customers/"+itoa(id), "请在弹窗里确认删除")
		return
	}
	if err := s.db.DeleteCustomer(id); err != nil {
		s.redirect(w, r, "/customers/"+itoa(id), "删除失败："+err.Error())
		return
	}
	s.logOp(r, "删除客户", "customer", id, c.Tail+" "+c.Name+"（含订阅与打卡记录）")
	s.redirect(w, r, "/customers", "已彻底删除客户 "+c.Tail+" "+c.Name)
}

// handleCustomerAssignee 从客户详情快速指派/取消打手。
func (s *Server) handleCustomerAssignee(w http.ResponseWriter, r *http.Request) {
	id := pathID(r)
	userID := int64(s.formInt(r, "assignee_id", 0))
	if err := s.db.SetCustomerAssignee(id, userID); err != nil {
		s.redirect(w, r, "/customers/"+itoa(id), "指派失败："+err.Error())
		return
	}
	c, _ := s.db.Customer(id)
	word := "已取消指派"
	if userID > 0 {
		if u, err := s.db.UserByID(userID); err == nil {
			name := u.DisplayName
			if name == "" {
				name = u.Username
			}
			word = "已指派给 " + name
		}
	}
	if c != nil {
		s.logOp(r, "指派打手", "customer", id, c.Tail+" "+c.Name+" "+word)
	}
	s.redirect(w, r, "/customers/"+itoa(id), word)
}

func (s *Server) handleSubCreate(w http.ResponseWriter, r *http.Request) {
	customerID := pathID(r)
	c, err := s.db.Customer(customerID)
	if err != nil {
		http.NotFound(w, r)
		return
	}
	in := store.CreateSubInput{
		CustomerID: customerID,
		PackageID:  int64(s.formInt(r, "package_id", 0)),
		StartDate:  r.PostFormValue("start_date"),
		EndDate:    r.PostFormValue("end_date"),
		Days:       s.formInt(r, "days", 0),
		TotalCount: s.formInt(r, "total_count", 0),
		Note:       strings.TrimSpace(r.PostFormValue("note")),
	}
	u := s.currentUser(r)
	if u != nil {
		in.OperatorID = u.ID
	}
	sub, err := s.db.CreateSub(in)
	if err != nil {
		s.redirect(w, r, "/customers/"+itoa(customerID), "创建订阅失败："+err.Error())
		return
	}
	s.logOp(r, "新建订阅", "subscription", sub.ID,
		"为 "+c.Tail+" "+c.Name+" 开通 "+sub.PackageName+"（"+unitLabel(sub.Unit)+"）")
	s.redirect(w, r, "/customers/"+itoa(customerID), "已开通「"+sub.PackageName+"」")
}

func unitLabel(u string) string {
	if u == domain.UnitCount {
		return "按次"
	}
	return "按日"
}

func itoa(v int64) string { return strconv.FormatInt(v, 10) }

func sortAdjustments(list []store.Adjustment) {
	sort.SliceStable(list, func(i, j int) bool {
		if list[i].CreatedAt != list[j].CreatedAt {
			return list[i].CreatedAt > list[j].CreatedAt
		}
		return list[i].ID > list[j].ID
	})
}

func sortCheckins(list []CheckinRow) {
	sort.SliceStable(list, func(i, j int) bool {
		if list[i].ServiceDate != list[j].ServiceDate {
			return list[i].ServiceDate > list[j].ServiceDate
		}
		return list[i].ID > list[j].ID
	})
}