package httpapi

import (
	"net/http"
	"strconv"
	"time"

	"spin/internal/models"
	"spin/internal/worktime"

	"github.com/go-chi/chi/v5"
)

// scopeEmail resolves which member's data a request targets. Members are always
// scoped to themselves; admins may pass ?email= to inspect anyone (or "" = all).
func (s *Server) scopeEmail(r *http.Request) (email string, all bool) {
	if !s.isAdmin(r) {
		return s.email(r), false
	}
	q := lc(r.URL.Query().Get("email"))
	if q == "" {
		return "", true
	}
	return q, false
}

// ---- attendance -----------------------------------------------------------

func (s *Server) handleListAttendance(w http.ResponseWriter, r *http.Request) {
	email, all := s.scopeEmail(r)
	q := s.db.Order("date desc")
	if !all {
		q = q.Where("lower(member_email) = ?", email)
	}
	if month := r.URL.Query().Get("month"); month != "" { // YYYY-MM
		q = q.Where("date LIKE ?", month+"%")
	}
	var out []models.Attendance
	q.Find(&out)
	writeJSON(w, http.StatusOK, out)
}

// handlePunch records a clock-in (first call of the day) or clock-out.
func (s *Server) handlePunch(w http.ResponseWriter, r *http.Request) {
	email := s.email(r)
	now := time.Now()
	date := now.Format("2006-01-02")
	pol := s.activeWorkPolicy()

	var a models.Attendance
	err := s.db.Where("lower(member_email) = ? AND date = ?", email, date).First(&a).Error
	if err != nil {
		a = models.Attendance{MemberEmail: email, Date: date, ClockIn: &now, Source: "web"}
		s.db.Create(&a)
		writeJSON(w, http.StatusOK, a)
		return
	}
	// already has a record → set clock-out and compute worked minutes
	a.ClockOut = &now
	a.WorkMinutes = worktime.NetWorkMinutes(a.ClockIn, a.ClockOut, pol.LunchMinutes)
	s.db.Save(&a)
	writeJSON(w, http.StatusOK, a)
}

// handleTimesheet returns the monthly roll-up for the scoped member.
func (s *Server) handleTimesheet(w http.ResponseWriter, r *http.Request) {
	email := s.email(r)
	if s.isAdmin(r) {
		if q := lc(r.URL.Query().Get("email")); q != "" {
			email = q
		}
	}
	now := time.Now()
	year, _ := strconv.Atoi(r.URL.Query().Get("year"))
	month, _ := strconv.Atoi(r.URL.Query().Get("month"))
	if year == 0 {
		year = now.Year()
	}
	if month == 0 {
		month = int(now.Month())
	}
	prefix := strconv.Itoa(year) + "-" + pad2(month)
	pol := s.activeWorkPolicy()

	var att []models.Attendance
	s.db.Where("lower(member_email) = ? AND date LIKE ?", email, prefix+"%").Find(&att)
	worked, days := 0, 0
	for _, a := range att {
		worked += a.WorkMinutes
		if a.WorkMinutes > 0 {
			days++
		}
	}

	// recognized leave minutes (approved annual/public/etc within month)
	var leaves []models.LeaveRequest
	s.db.Where("lower(member_email) = ? AND status = ? AND start_date LIKE ?",
		email, models.StatusApproved, prefix+"%").Find(&leaves)
	leaveMin := 0
	for _, lv := range leaves {
		if lv.Type == models.LeaveUnpaid {
			continue
		}
		leaveMin += int(lv.Days * float64(pol.DailyStandardMin))
	}

	var ots []models.OvertimeRequest
	s.db.Where("lower(member_email) = ? AND status = ? AND date LIKE ?",
		email, models.StatusApproved, prefix+"%").Find(&ots)
	otMin := 0
	for _, o := range ots {
		otMin += o.Minutes
	}

	writeJSON(w, http.StatusOK, worktime.Compute(year, month, pol.DailyStandardMin, worked, leaveMin, otMin, days))
}

func pad2(n int) string {
	if n < 10 {
		return "0" + strconv.Itoa(n)
	}
	return strconv.Itoa(n)
}

// ---- leave ----------------------------------------------------------------

func (s *Server) handleListLeave(w http.ResponseWriter, r *http.Request) {
	email, all := s.scopeEmail(r)
	q := s.db.Order("created_at desc")
	if !all {
		q = q.Where("lower(member_email) = ?", email)
	}
	if st := r.URL.Query().Get("status"); st != "" {
		q = q.Where("status = ?", st)
	}
	var out []models.LeaveRequest
	q.Find(&out)
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleCreateLeave(w http.ResponseWriter, r *http.Request) {
	var lv models.LeaveRequest
	if err := decodeJSON(r, &lv); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	lv.MemberEmail = s.email(r) // members can only file for themselves
	lv.Status = models.StatusPending
	lv.Approver = ""
	if lv.Days == 0 {
		lv.Days = leaveDays(lv)
	}
	if err := s.db.Create(&lv).Error; err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusCreated, lv)
}

// leaveDays estimates day count from the date span (half-day types = 0.5).
func leaveDays(lv models.LeaveRequest) float64 {
	if lv.Type == models.LeaveHalfAM || lv.Type == models.LeaveHalfPM {
		return 0.5
	}
	s, e1 := lv.StartDate, lv.EndDate
	if e1 == "" {
		e1 = s
	}
	t1, err1 := time.Parse("2006-01-02", s)
	t2, err2 := time.Parse("2006-01-02", e1)
	if err1 != nil || err2 != nil {
		return 1
	}
	return t2.Sub(t1).Hours()/24 + 1
}

type decision struct {
	Approve bool   `json:"approve"`
	Memo    string `json:"memo"`
}

func (s *Server) handleDecideLeave(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var lv models.LeaveRequest
	if err := s.db.First(&lv, "id = ?", chi.URLParam(r, "id")).Error; err != nil {
		writeError(w, http.StatusNotFound, "신청을 찾을 수 없습니다")
		return
	}
	var d decision
	decodeJSON(r, &d)
	now := time.Now()
	lv.Status = models.StatusRejected
	if d.Approve {
		lv.Status = models.StatusApproved
		s.applyLeaveBalance(lv)
	}
	lv.Approver = currentUser(r.Context()).Email
	lv.DecidedAt = &now
	lv.DecisionMemo = d.Memo
	s.db.Save(&lv)
	s.audit(r, "decide", "leave", lv.ID, lv.Status)
	writeJSON(w, http.StatusOK, lv)
}

// applyLeaveBalance draws down the annual leave balance for 연차 types.
func (s *Server) applyLeaveBalance(lv models.LeaveRequest) {
	if lv.Type != models.LeaveAnnual && lv.Type != models.LeaveHalfAM && lv.Type != models.LeaveHalfPM {
		return
	}
	year := time.Now().Year()
	if t, err := time.Parse("2006-01-02", lv.StartDate); err == nil {
		year = t.Year()
	}
	var bal models.LeaveBalance
	if err := s.db.Where("lower(member_email) = ? AND year = ?", lc(lv.MemberEmail), year).First(&bal).Error; err != nil {
		bal = models.LeaveBalance{MemberEmail: lv.MemberEmail, Year: year, Granted: 15}
		s.db.Create(&bal)
	}
	bal.Used += lv.Days
	s.db.Save(&bal)
}

func (s *Server) handleCancelLeave(w http.ResponseWriter, r *http.Request) {
	var lv models.LeaveRequest
	if err := s.db.First(&lv, "id = ?", chi.URLParam(r, "id")).Error; err != nil {
		writeError(w, http.StatusNotFound, "신청을 찾을 수 없습니다")
		return
	}
	if !s.isAdmin(r) && !s.owns(r, lv.MemberEmail) {
		writeError(w, http.StatusForbidden, "본인 신청만 취소할 수 있습니다")
		return
	}
	lv.Status = models.StatusCanceled
	s.db.Save(&lv)
	writeJSON(w, http.StatusOK, lv)
}

// ---- overtime -------------------------------------------------------------

func (s *Server) handleListOvertime(w http.ResponseWriter, r *http.Request) {
	email, all := s.scopeEmail(r)
	q := s.db.Order("created_at desc")
	if !all {
		q = q.Where("lower(member_email) = ?", email)
	}
	var out []models.OvertimeRequest
	q.Find(&out)
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleCreateOvertime(w http.ResponseWriter, r *http.Request) {
	var o models.OvertimeRequest
	if err := decodeJSON(r, &o); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	o.MemberEmail = s.email(r)
	o.Status = models.StatusPending
	if err := s.db.Create(&o).Error; err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusCreated, o)
}

func (s *Server) handleDecideOvertime(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var o models.OvertimeRequest
	if err := s.db.First(&o, "id = ?", chi.URLParam(r, "id")).Error; err != nil {
		writeError(w, http.StatusNotFound, "신청을 찾을 수 없습니다")
		return
	}
	var d decision
	decodeJSON(r, &d)
	now := time.Now()
	o.Status = models.StatusRejected
	if d.Approve {
		o.Status = models.StatusApproved
	}
	o.Approver = currentUser(r.Context()).Email
	o.DecidedAt = &now
	o.DecisionMemo = d.Memo
	s.db.Save(&o)
	s.audit(r, "decide", "overtime", o.ID, o.Status)
	writeJSON(w, http.StatusOK, o)
}

// ---- work policy ----------------------------------------------------------

// activeWorkPolicy returns the active policy or a sane default.
func (s *Server) activeWorkPolicy() models.WorkPolicy {
	var p models.WorkPolicy
	if err := s.db.Where("active = ?", true).First(&p).Error; err != nil {
		return models.WorkPolicy{WeeklyHours: 40, DailyStandardMin: 480, LunchMinutes: 60,
			CoreStart: "09:00", CoreEnd: "18:00", AnnualLeaveBase: 15, Active: true}
	}
	return p
}

func (s *Server) handleGetWorkPolicy(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, http.StatusOK, s.activeWorkPolicy())
}

func (s *Server) handlePutWorkPolicy(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var in models.WorkPolicy
	if err := decodeJSON(r, &in); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	var p models.WorkPolicy
	if err := s.db.Where("active = ?", true).First(&p).Error; err != nil {
		in.Active = true
		s.db.Create(&in)
		writeJSON(w, http.StatusOK, in)
		return
	}
	in.ID = p.ID
	in.Active = true
	s.db.Save(&in)
	writeJSON(w, http.StatusOK, in)
}

// ---- approval queue (admin) ----------------------------------------------

type approvalQueue struct {
	Leave    []models.LeaveRequest    `json:"leave"`
	Overtime []models.OvertimeRequest `json:"overtime"`
}

func (s *Server) handleApprovalQueue(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var q approvalQueue
	s.db.Where("status = ?", models.StatusPending).Order("created_at asc").Find(&q.Leave)
	s.db.Where("status = ?", models.StatusPending).Order("created_at asc").Find(&q.Overtime)
	writeJSON(w, http.StatusOK, q)
}