package web

import (
	"fmt"
	"net"
	"net/http"
	"net/url"
	"regexp"
	"strings"
	"sync"
	"time"

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

// portalDay 客户自助月历中的一天：日常任务按 done/total 计，通行证/深渊按整段色块展示。
type portalDay struct {
	Date    string
	Day     int
	InMonth bool
	Today   bool
	Total   int
	Done    int
	// 通行证 / 深渊色块
	BlockColor   string
	BlockText    string
	BlockTitle   string
	BlockPercent int
	// Label 是读屏用的整格描述
	Label string
}

// portalSub 客户自助页里的一个订阅；复用管理端 SubView 的状态/剩余文案。
type portalSub struct {
	SubView
	TodayLabel string
	TodayClass string
}

// portalAsk 同一尾号命中多个客户时要求补姓名。
type portalAsk struct {
	Tail   string
	Count  int
	Masked []string
}

// portalView 客户自助查询结果。
type portalView struct {
	Tail         string
	Name         string
	Game         string
	Subs         []portalSub
	Weeks        [][]portalDay
	MonthTitle   string
	Prev         string
	Next         string
	TodayTotal   int
	TodayDone    int
	TodayPending int
	TodayState   string // done / pending / none
	SubCount     int
	Expiring     string
	Masked       []string
}

var portalTailRe = regexp.MustCompile(`^\d{4,8}$`)

const (
	portalRateLimit  = 40
	portalRateWindow = time.Minute
)

var portalHits = struct {
	sync.Mutex
	m map[string][]time.Time
}{m: map[string][]time.Time{}}

// allowPortal 对自助查询做简单的按 IP 限流，避免尾号枚举把库打穿。
func allowPortal(remote string) bool {
	host, _, err := net.SplitHostPort(remote)
	if err != nil || host == "" {
		host = remote
	}
	now := time.Now()
	portalHits.Lock()
	defer portalHits.Unlock()
	kept := portalHits.m[host][:0]
	for _, t := range portalHits.m[host] {
		if now.Sub(t) < portalRateWindow {
			kept = append(kept, t)
		}
	}
	if len(kept) >= portalRateLimit {
		portalHits.m[host] = kept
		return false
	}
	portalHits.m[host] = append(kept, now)
	return true
}

// handleCustomerPortal 客户自助查询页（公开，无入口链接）。
func (s *Server) handleCustomerPortal(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("X-Robots-Tag", "noindex, nofollow")
	p := s.newPage(r, "排单查询", "")
	q := r.URL.Query()
	tail := strings.TrimSpace(q.Get("tail"))
	name := strings.TrimSpace(q.Get("name"))
	month := strings.TrimSpace(q.Get("cm"))
	p.Query = tail
	p.Name = name

	if tail == "" {
		s.render(w, r, "portal", p)
		return
	}
	if !allowPortal(r.RemoteAddr) {
		p.InlineError = "查询太频繁，请稍后再试"
		s.render(w, r, "portal", p)
		return
	}
	if !portalTailRe.MatchString(tail) {
		p.InlineError = "请输入 4–8 位数字手机尾号"
		p.InvalidField = "tail"
		s.render(w, r, "portal", p)
		return
	}

	list, err := s.db.CustomersByTailExact(tail)
	if err != nil {
		p.InlineError = "读取客户失败，请稍后再试"
		s.render(w, r, "portal", p)
		return
	}
	if len(list) == 0 {
		p.InlineError = "没有找到这个尾号的客户，请核对尾号"
		p.InvalidField = "tail"
		s.render(w, r, "portal", p)
		return
	}
	if len(list) > 1 {
		if name == "" {
			p.D = &portalAsk{Tail: tail, Count: len(list), Masked: maskNames(list)}
			s.render(w, r, "portal", p)
			return
		}
		matched := matchByName(list, name)
		if len(matched) == 0 {
			p.InlineError = "尾号对得上，但姓名不匹配，请再确认一下"
			p.InvalidField = "name"
			s.render(w, r, "portal", p)
			return
		}
		if len(matched) > 1 {
			p.D = &portalAsk{Tail: tail, Count: len(matched), Masked: maskNames(matched)}
			s.render(w, r, "portal", p)
			return
		}
		list = matched
	}

	c := list[0]
	p.D = s.buildPortal(c, tail, name, month)
	s.render(w, r, "portal", p)
}

func matchByName(list []store.Customer, name string) []store.Customer {
	needle := strings.ToLower(strings.TrimSpace(name))
	out := make([]store.Customer, 0, len(list))
	for _, c := range list {
		if strings.Contains(strings.ToLower(c.Name), needle) {
			out = append(out, c)
		}
	}
	return out
}

func maskNames(list []store.Customer) []string {
	out := make([]string, 0, len(list))
	seen := map[string]bool{}
	for _, c := range list {
		m := maskName(c.Name)
		if seen[m] {
			continue
		}
		seen[m] = true
		out = append(out, m)
	}
	return out
}

// maskName 只保留首字，避免多客户态直接列出全名。
func maskName(name string) string {
	rs := []rune(strings.TrimSpace(name))
	switch len(rs) {
	case 0:
		return "*"
	case 1:
		return "*"
	}
	return string(rs[0]) + strings.Repeat("*", len(rs)-1)
}

// buildPortal 组装某位客户的排单视图。
func (s *Server) buildPortal(c store.Customer, tail, name, month string) *portalView {
	today := domain.Today()
	todayStr := domain.Date(today)
	warn := s.warnDays()
	first := time.Date(today.Year(), today.Month(), 1, 0, 0, 0, 0, time.UTC)
	if month != "" {
		if t, err := time.Parse("2006-01", month); err == nil {
			first = t
		}
	}
	year, mon := first.Year(), int(first.Month())
	firstDay := time.Date(year, time.Month(mon), 1, 0, 0, 0, 0, time.UTC)
	lastDay := firstDay.AddDate(0, 1, -1)
	start := firstDay.AddDate(0, 0, -((int(firstDay.Weekday()) + 6) % 7))
	end := lastDay.AddDate(0, 0, 6-((int(lastDay.Weekday())+6)%7))

	allSubs, _ := s.db.SubsByCustomer(c.ID)
	subs := make([]store.Subscription, 0, len(allSubs))
	ids := make([]int64, 0, len(allSubs))
	for _, sub := range allSubs {
		if sub.Status == domain.StatusClosed {
			continue
		}
		subs = append(subs, sub)
		ids = append(ids, sub.ID)
	}

	cks, _ := s.db.CheckinsForSubs(ids, wideFrom(domain.Date(start)), wideTo(domain.Date(end)))
	pauses, _ := s.db.PausesForSubs(ids)
	cals := make([]calSub, 0, len(subs))
	for _, sub := range subs {
		cs := calSub{
			sub:      sub,
			start:    domain.ParseDateOr(sub.StartDate, today),
			eval:     sub.Eval(today, warn),
			pauses:   pauses[sub.ID],
			checkins: cks[sub.ID],
		}
		if sub.EndDate != "" {
			cs.hasEnd = true
			cs.end = domain.ParseDateOr(sub.EndDate, today)
		}
		cals = append(cals, cs)
	}

	v := &portalView{
		Tail:     c.Tail,
		Name:     c.Name,
		Game:     c.GameName,
		SubCount: len(subs),
	}
	v.MonthTitle = fmt.Sprintf("%d 年 %d 月", year, mon)
	v.Prev = portalQuery(tail, name, firstDay.AddDate(0, -1, 0).Format("2006-01"))
	v.Next = portalQuery(tail, name, firstDay.AddDate(0, 1, 0).Format("2006-01"))

	for _, cs := range cals {
		sub := cs.sub
		ev := newSubView(sub, today, warn)
		ps := portalSub{SubView: ev}
		if ev.StateClass == "active" && !sub.Season && !sub.Abyss && cs.covers(todayStr) {
			if ci, ok := cks[sub.ID][todayStr]; ok && portalDone(ci) {
				ps.TodayLabel, ps.TodayClass = "今日已完成", "active"
			} else {
				ps.TodayLabel, ps.TodayClass = "今日未完成", "plain"
			}
		}
		v.Subs = append(v.Subs, ps)

		if sub.EndDate != "" && sub.EndDate >= todayStr {
			switch ev.Eval.State {
			case domain.StateExpired, domain.StateUsedUp, domain.StateClosed:
			default:
				if v.Expiring == "" || sub.EndDate < v.Expiring {
					v.Expiring = sub.EndDate
				}
			}
		}
	}

	// 月历
	days := int(end.Sub(start).Hours()/24) + 1
	week := make([]portalDay, 0, 7)
	for i := 0; i < days; i++ {
		d := start.AddDate(0, 0, i)
		ds := domain.Date(d)
		pd := portalDay{Date: ds, Day: d.Day(), InMonth: d.Month() == time.Month(mon), Today: ds == todayStr}
		// 与主日历一致：只在本月格子里显示任务，前后月只做日期占位。
		if pd.InMonth {
			for _, cs := range cals {
				sub := cs.sub
				if cs.isBlock() {
					if cs.blockCovers(ds) && pd.BlockText == "" {
						pd.BlockColor = sub.PackageColor
						pd.BlockText = blockCellText(cs, ds)
						pd.BlockTitle = sub.PackageName + " · " + pd.BlockText
						pd.BlockPercent = blockCellPercent(cs, d)
					}
					continue
				}
				if !cs.covers(ds) {
					continue
				}
				pd.Total++
				if ci, ok := cks[sub.ID][ds]; ok && portalDone(ci) {
					pd.Done++
				}
			}
		}
		pd.Label = portalDayLabel(pd, mon)
		week = append(week, pd)
		if len(week) == 7 {
			v.Weeks = append(v.Weeks, week)
			week = make([]portalDay, 0, 7)
		}
	}
	if len(week) > 0 {
		v.Weeks = append(v.Weeks, week)
	}

	// 今日进度：整段型订阅算 1 项，通行证看 season_done，深渊看当天所在周期。
	for _, cs := range cals {
		if cs.isBlock() {
			if cs.blockCovers(todayStr) {
				v.TodayTotal++
				if !cs.blockNeedsWork(todayStr) {
					v.TodayDone++
				}
			}
			continue
		}
		if !cs.covers(todayStr) {
			continue
		}
		v.TodayTotal++
		if ci, ok := cks[cs.sub.ID][todayStr]; ok && portalDone(ci) {
			v.TodayDone++
		}
	}
	v.TodayPending = v.TodayTotal - v.TodayDone
	switch {
	case v.TodayTotal == 0:
		v.TodayState = "none"
	case v.TodayPending <= 0:
		v.TodayState = "done"
	default:
		v.TodayState = "pending"
	}
	return v
}

// portalDone 与管理端日历口径一致：done 和 skipped 都算当天已处理。
func portalDone(ci store.Checkin) bool {
	return ci.Status == "done" || ci.Status == "skipped"
}

func portalDayLabel(pd portalDay, month int) string {
	labelMonth := month
	if t, err := time.Parse("2006-01-02", pd.Date); err == nil {
		labelMonth = int(t.Month())
	}
	label := fmt.Sprintf("%d 月 %d 日", labelMonth, pd.Day)
	if pd.Today {
		label += "，今天"
	}
	if pd.BlockText != "" {
		label += "，" + pd.BlockTitle
	}
	if pd.Total > 0 {
		label += fmt.Sprintf("，共 %d 单，已完成 %d 单", pd.Total, pd.Done)
	}
	if pd.BlockText == "" && pd.Total == 0 {
		label += "，无排单"
	}
	return label
}

// portalQuery 用 url.Values 拼翻月链接，姓名含 & / 空格时也不会丢参数。
func portalQuery(tail, name, month string) string {
	q := url.Values{}
	q.Set("tail", tail)
	if name != "" {
		q.Set("name", name)
	}
	q.Set("cm", month)
	return "/customer?" + q.Encode()
}