package httpapi

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

	"spin/internal/models"

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

// All accounting is admin-only (전사 재무 데이터).

func (s *Server) handleListAccounts(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var out []models.Account
	s.db.Order("code asc").Find(&out)
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleCreateAccount(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var a models.Account
	if err := decodeJSON(r, &a); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	s.db.Create(&a)
	writeJSON(w, http.StatusCreated, a)
}

func (s *Server) handleListTransactions(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	q := s.db.Order("date desc, created_at desc")
	if k := r.URL.Query().Get("kind"); k != "" {
		q = q.Where("kind = ?", k)
	}
	if pid := r.URL.Query().Get("projectId"); pid != "" {
		q = q.Where("project_id = ?", pid)
	}
	if from := r.URL.Query().Get("from"); from != "" {
		q = q.Where("date >= ?", from)
	}
	if to := r.URL.Query().Get("to"); to != "" {
		q = q.Where("date <= ?", to)
	}
	var out []models.Transaction
	q.Limit(1000).Find(&out)
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleCreateTransaction(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var t models.Transaction
	if err := decodeJSON(r, &t); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	t.CreatedBy = currentUser(r.Context()).Email
	s.db.Create(&t)
	s.audit(r, "create", "transaction", t.ID, t.Kind)
	writeJSON(w, http.StatusCreated, t)
}

func (s *Server) handlePatchTransaction(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var t models.Transaction
	if err := s.db.First(&t, "id = ?", chi.URLParam(r, "txId")).Error; err != nil {
		writeError(w, http.StatusNotFound, "거래를 찾을 수 없습니다")
		return
	}
	var patch map[string]interface{}
	if err := decodeJSON(r, &patch); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	delete(patch, "id")
	s.db.Model(&t).Updates(patch)
	s.db.First(&t, "id = ?", t.ID)
	writeJSON(w, http.StatusOK, t)
}

func (s *Server) handleDeleteTransaction(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	s.db.Delete(&models.Transaction{}, "id = ?", chi.URLParam(r, "txId"))
	writeJSON(w, http.StatusOK, map[string]bool{"ok": true})
}

func (s *Server) handleListTaxes(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var out []models.TaxRecord
	s.db.Order("due_date desc").Find(&out)
	writeJSON(w, http.StatusOK, out)
}

func (s *Server) handleCreateTax(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var t models.TaxRecord
	if err := decodeJSON(r, &t); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	s.db.Create(&t)
	writeJSON(w, http.StatusCreated, t)
}

func (s *Server) handlePatchTax(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var t models.TaxRecord
	if err := s.db.First(&t, "id = ?", chi.URLParam(r, "taxId")).Error; err != nil {
		writeError(w, http.StatusNotFound, "세금 항목을 찾을 수 없습니다")
		return
	}
	var patch map[string]interface{}
	if err := decodeJSON(r, &patch); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	delete(patch, "id")
	s.db.Model(&t).Updates(patch)
	s.db.First(&t, "id = ?", t.ID)
	writeJSON(w, http.StatusOK, t)
}

// ---- summary: cashflow vs incentive gap -----------------------------------

type acctSummary struct {
	Year            int                  `json:"year"`
	CashIn          float64              `json:"cashIn"`
	CashOut         float64              `json:"cashOut"`
	Net             float64              `json:"net"`
	IncentiveApplied float64             `json:"incentiveApplied"` // KRW value of applied points
	IncentivePaid   float64              `json:"incentivePaid"`    // actually disbursed (지급완료)
	Gap             float64              `json:"gap"`              // applied − paid (미지급 부채성)
	Monthly         []monthlyPL          `json:"monthly"`
	ByKind          map[string]float64   `json:"byKind"`
}

type monthlyPL struct {
	Month   string  `json:"month"`
	Income  float64 `json:"income"`
	Expense float64 `json:"expense"`
	Net     float64 `json:"net"`
}

func (s *Server) handleAccountingSummary(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	year := yearParam(r)
	prefix := strconv.Itoa(year)
	var txns []models.Transaction
	s.db.Where("date LIKE ?", prefix+"%").Find(&txns)

	sum := acctSummary{Year: year, ByKind: map[string]float64{}}
	monthly := map[string]*monthlyPL{}
	for m := 1; m <= 12; m++ {
		key := prefix + "-" + pad2(m)
		monthly[key] = &monthlyPL{Month: key}
	}
	for _, t := range txns {
		sum.ByKind[t.Kind] += t.Amount
		mk := t.Date
		if len(mk) >= 7 {
			mk = mk[:7]
		}
		row := monthly[mk]
		if row == nil {
			row = &monthlyPL{Month: mk}
			monthly[mk] = row
		}
		if t.Kind == models.TxnIncome {
			sum.CashIn += t.Amount
			row.Income += t.Amount
		} else {
			out := t.Amount
			if out < 0 {
				out = -out
			}
			sum.CashOut += out
			row.Expense += out
		}
		row.Net = row.Income - row.Expense
	}
	sum.Net = sum.CashIn - sum.CashOut

	// incentive applied (반영완료/지급완료) point value vs actually paid (지급완료)
	var appliedPts, paidPts float64
	s.db.Model(&models.UserIncentive{}).Where("year = ? AND (fix_status = ? OR fix_status = ?)",
		year, models.FixApplied, models.FixPaid).Select("COALESCE(SUM(points),0)").Scan(&appliedPts)
	s.db.Model(&models.UserIncentive{}).Where("year = ? AND fix_status = ?",
		year, models.FixPaid).Select("COALESCE(SUM(points),0)").Scan(&paidPts)
	_, eng := s.incentiveConfig(year)
	sum.IncentiveApplied = appliedPts * eng.PointRate
	sum.IncentivePaid = paidPts * eng.PointRate
	sum.Gap = sum.IncentiveApplied - sum.IncentivePaid

	// ordered monthly slice
	for m := 1; m <= 12; m++ {
		key := prefix + "-" + pad2(m)
		sum.Monthly = append(sum.Monthly, *monthly[key])
	}
	writeJSON(w, http.StatusOK, sum)
}

var _ = time.Now