package httpapi

import (
	"encoding/json"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"spin/internal/incentive"
	"spin/internal/models"

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

// ---- config ---------------------------------------------------------------

// incentiveConfig loads (or defaults) the IncentiveConfig for a year and adapts
// it to the engine's plain Config.
func (s *Server) incentiveConfig(year int) (models.IncentiveConfig, incentive.Config) {
	var c models.IncentiveConfig
	if err := s.db.Where("year = ?", year).First(&c).Error; err != nil {
		c = models.IncentiveConfig{Year: year, PointRate: 1_000_000, DepositPct: 30,
			MiddlePct: 40, FinalPct: 30, NonBECompanyPct: 60, NonBEPartnerPct: 40,
			RankQuota: defaultQuota()}
	}
	return c, toEngineConfig(c)
}

func defaultQuota() map[string]interface{} {
	return map[string]interface{}{
		models.RankIntern: 15.0, models.RankJunior: 30.0, models.RankSenior: 50.0,
		models.RankLead: 80.0, models.RankPartner: 120.0,
	}
}

func toEngineConfig(c models.IncentiveConfig) incentive.Config {
	quota := map[string]float64{}
	for k, v := range c.RankQuota {
		if f, ok := toFloat(v); ok {
			quota[k] = f
		}
	}
	return incentive.Config{
		PointRate: c.PointRate, DepositPct: c.DepositPct, MiddlePct: c.MiddlePct,
		FinalPct: c.FinalPct, NonBECompanyPct: c.NonBECompanyPct,
		NonBEPartnerPct: c.NonBEPartnerPct, RankQuota: quota,
	}
}

func toFloat(v interface{}) (float64, bool) {
	switch n := v.(type) {
	case float64:
		return n, true
	case float32:
		return float64(n), true
	case int:
		return float64(n), true
	case int64:
		return float64(n), true
	case json.Number:
		// GORM's datatypes.JSONMap decodes JSON numbers as json.Number.
		f, err := n.Float64()
		return f, err == nil
	case string:
		f, err := strconv.ParseFloat(n, 64)
		return f, err == nil
	}
	return 0, false
}

func yearParam(r *http.Request) int {
	if y, err := strconv.Atoi(r.URL.Query().Get("year")); err == nil && y > 0 {
		return y
	}
	return time.Now().Year()
}

func (s *Server) handleGetIncentiveConfig(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	c, _ := s.incentiveConfig(yearParam(r))
	writeJSON(w, http.StatusOK, c)
}

func (s *Server) handlePutIncentiveConfig(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var in models.IncentiveConfig
	if err := decodeJSON(r, &in); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	if in.Year == 0 {
		in.Year = time.Now().Year()
	}
	var existing models.IncentiveConfig
	if err := s.db.Where("year = ?", in.Year).First(&existing).Error; err == nil {
		in.ID = existing.ID
		s.db.Save(&in)
	} else {
		s.db.Create(&in)
	}
	s.audit(r, "update", "incentive_config", strconv.Itoa(in.Year), "")
	writeJSON(w, http.StatusOK, in)
}

// ---- recompute (rebuild stages + allocations from contract) ---------------

func (s *Server) projectMemberPortions(projectID string) []incentive.MemberPortion {
	var pms []models.ProjectMember
	s.db.Where("project_id = ?", projectID).Find(&pms)
	out := make([]incentive.MemberPortion, 0, len(pms))
	for _, pm := range pms {
		isPartner := false
		if m := s.lookupMember(pm.MemberEmail); m != nil {
			isPartner = m.IsPartner || m.Rank == models.RankPartner
		}
		out = append(out, incentive.MemberPortion{Email: pm.MemberEmail, Portion: pm.Portion, IsPartner: isPartner})
	}
	return out
}

func (s *Server) handleRecomputeProject(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	pid := chi.URLParam(r, "id")
	var contract models.Contract
	if err := s.db.First(&contract, "project_id = ?", pid).Error; err != nil {
		writeError(w, http.StatusBadRequest, "계약 정보(BE/계약금액)를 먼저 입력하세요")
		return
	}
	year := yearParam(r)
	_, eng := s.incentiveConfig(year)
	stages := incentive.ComputeStages(contract.TotalAmount, contract.BEAmount, eng)

	// upsert PaymentStage rows (keep status/dates on existing kind×scope).
	for _, st := range stages {
		var existing models.PaymentStage
		err := s.db.Where("project_id = ? AND kind = ? AND scope = ?", pid, st.Kind, st.Scope).First(&existing).Error
		if err != nil {
			s.db.Create(&models.PaymentStage{ProjectID: pid, Kind: st.Kind, Scope: st.Scope,
				Amount: st.Amount, Pct: st.Pct, Status: models.FixPlanned})
		} else {
			existing.Amount = st.Amount
			existing.Pct = st.Pct
			s.db.Save(&existing)
		}
	}

	// rebuild non-override UserIncentive rows.
	members := s.projectMemberPortions(pid)
	allocs := incentive.ComputeAllocs(stages, members, eng)
	s.db.Where("project_id = ? AND \"override\" = ?", pid, false).Delete(&models.UserIncentive{})
	var stageRows []models.PaymentStage
	s.db.Where("project_id = ?", pid).Find(&stageRows)
	stageID := map[string]string{}
	stageStatus := map[string]string{}
	for _, sr := range stageRows {
		stageID[sr.Kind+"|"+sr.Scope] = sr.ID
		stageStatus[sr.Kind+"|"+sr.Scope] = sr.Status
	}
	for _, a := range allocs {
		key := a.Kind + "|" + a.Scope
		// skip member+stage that already has an override row
		var cnt int64
		s.db.Model(&models.UserIncentive{}).
			Where("project_id = ? AND lower(member_email) = lower(?) AND kind = ? AND scope = ? AND \"override\" = ?",
				pid, a.Email, a.Kind, a.Scope, true).Count(&cnt)
		if cnt > 0 {
			continue
		}
		s.db.Create(&models.UserIncentive{ProjectID: pid, MemberEmail: a.Email, StageID: stageID[key],
			Kind: a.Kind, Scope: a.Scope, Year: year, Portion: a.Portion, Amount: a.Amount,
			Points: a.Points, FixStatus: stageStatus[key]})
	}
	s.audit(r, "recompute", "incentive", pid, "")
	writeJSON(w, http.StatusOK, map[string]interface{}{"stages": len(stages), "allocs": len(allocs)})
}

func (s *Server) handleListStages(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var out []models.PaymentStage
	q := s.db.Order("scope asc, kind asc")
	if pid := r.URL.Query().Get("projectId"); pid != "" {
		q = q.Where("project_id = ?", pid)
	}
	q.Find(&out)
	writeJSON(w, http.StatusOK, out)
}

// handleSetStageStatus toggles a stage's fix lifecycle and propagates the status
// to its non-override UserIncentive rows (반영중 → 반영완료 등).
func (s *Server) handleSetStageStatus(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var st models.PaymentStage
	if err := s.db.First(&st, "id = ?", chi.URLParam(r, "stId")).Error; err != nil {
		writeError(w, http.StatusNotFound, "단계를 찾을 수 없습니다")
		return
	}
	var body struct {
		Status    string `json:"status"`
		FixedDate string `json:"fixedDate"`
	}
	decodeJSON(r, &body)
	st.Status = body.Status
	if body.FixedDate != "" {
		st.FixedDate = body.FixedDate
	}
	s.db.Save(&st)
	// propagate to non-override allocations
	now := time.Now()
	updates := map[string]interface{}{"fix_status": body.Status}
	if body.Status == models.FixApplied {
		updates["applied_at"] = &now
	}
	if body.Status == models.FixPaid {
		updates["paid_at"] = &now
	}
	s.db.Model(&models.UserIncentive{}).
		Where("stage_id = ? AND \"override\" = ?", st.ID, false).Updates(updates)
	s.audit(r, "stage_status", "payment_stage", st.ID, body.Status)
	// notify affected members on 반영완료/지급완료 (BE/non-BE 등 내부 개념은 노출하지 않음)
	if body.Status == models.FixApplied || body.Status == models.FixPaid {
		msg := "인센티브 포인트가 반영되었습니다."
		if body.Status == models.FixPaid {
			msg = "인센티브가 지급되었습니다."
		}
		var emails []string
		s.db.Model(&models.UserIncentive{}).Where("stage_id = ?", st.ID).Distinct().Pluck("member_email", &emails)
		for _, e := range emails {
			s.notify(e, "incentive", "인센티브 업데이트", msg, "/incentive")
		}
	}
	writeJSON(w, http.StatusOK, st)
}

// ---- user incentives ------------------------------------------------------

func (s *Server) handleListUserIncentives(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	q := s.db.Order("created_at desc")
	if pid := r.URL.Query().Get("projectId"); pid != "" {
		q = q.Where("project_id = ?", pid)
	}
	if em := lc(r.URL.Query().Get("email")); em != "" {
		q = q.Where("lower(member_email) = ?", em)
	}
	var out []models.UserIncentive
	q.Find(&out)
	writeJSON(w, http.StatusOK, out)
}

// handlePatchUserIncentive is the custom-override entry point: any field can be
// hand-edited and the row is flagged Override so recompute won't clobber it.
func (s *Server) handlePatchUserIncentive(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var ui models.UserIncentive
	if err := s.db.First(&ui, "id = ?", chi.URLParam(r, "uiId")).Error; err != nil {
		writeError(w, http.StatusNotFound, "내역을 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")
	patch["override"] = true // any manual edit pins the row
	s.db.Model(&ui).Updates(patch)
	s.db.First(&ui, "id = ?", ui.ID)
	s.audit(r, "override", "user_incentive", ui.ID, "")
	writeJSON(w, http.StatusOK, ui)
}

// ---- member dashboard -----------------------------------------------------

type myIncentive struct {
	Year         int                    `json:"year"`
	Rank         string                 `json:"rank"`
	Quota        float64                `json:"quota"`
	PointsTotal  float64                `json:"pointsTotal"`  // all points (any status)
	PointsApplied float64               `json:"pointsApplied"` // applied+paid
	ExcessPoints float64                `json:"excessPoints"`
	PointRate    float64                `json:"pointRate"`
	EstPayout    float64                `json:"estPayout"`
	Items        []models.UserIncentive `json:"items"`
	ByProject    map[string]float64     `json:"byProject"`
}

func (s *Server) handleMyIncentive(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
		}
	}
	year := yearParam(r)
	cfg, eng := s.incentiveConfig(year)

	var items []models.UserIncentive
	s.db.Where("lower(member_email) = ? AND year = ?", email, year).Order("created_at desc").Find(&items)

	total, applied := 0.0, 0.0
	byProject := map[string]float64{}
	for _, it := range items {
		total += it.Points
		if it.FixStatus == models.FixApplied || it.FixStatus == models.FixPaid {
			applied += it.Points
		}
		byProject[it.ProjectID] += it.Points
	}
	rank := ""
	if m := s.lookupMember(email); m != nil {
		rank = m.Rank
	}
	st := incentive.ComputeSettlement(email, rank, applied, 0, eng)
	writeJSON(w, http.StatusOK, myIncentive{
		Year: year, Rank: rank, Quota: st.Quota, PointsTotal: total, PointsApplied: applied,
		ExcessPoints: st.ExcessPoints, PointRate: cfg.PointRate, EstPayout: st.PayoutAmount,
		Items: items, ByProject: byProject,
	})
}

// ---- quarterly settlement -------------------------------------------------

func (s *Server) handleListSettlements(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	q := s.db.Order("year desc, quarter desc")
	if y, err := strconv.Atoi(r.URL.Query().Get("year")); err == nil && y > 0 {
		q = q.Where("year = ?", y)
	}
	var out []models.QuarterlySettlement
	q.Find(&out)
	writeJSON(w, http.StatusOK, out)
}

// handleRunSettlement computes (or refreshes) settlement rows for a year+quarter.
func (s *Server) handleRunSettlement(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var body struct {
		Year    int `json:"year"`
		Quarter int `json:"quarter"`
	}
	decodeJSON(r, &body)
	if body.Year == 0 {
		body.Year = time.Now().Year()
	}
	if body.Quarter == 0 {
		body.Quarter = (int(time.Now().Month())-1)/3 + 1
	}
	_, eng := s.incentiveConfig(body.Year)

	// applied points per member up to this quarter (cumulative within the year).
	var members []models.Member
	s.db.Find(&members)
	var results []models.QuarterlySettlement
	for _, m := range members {
		var applied float64
		s.db.Model(&models.UserIncentive{}).
			Where("lower(member_email) = lower(?) AND year = ? AND (fix_status = ? OR fix_status = ?)",
				m.Email, body.Year, models.FixApplied, models.FixPaid).
			Select("COALESCE(SUM(points),0)").Scan(&applied)
		// prior paid this year
		var paidYTD float64
		s.db.Model(&models.QuarterlySettlement{}).
			Where("lower(member_email) = lower(?) AND year = ? AND quarter < ? AND fixed = ?",
				m.Email, body.Year, body.Quarter, true).
			Select("COALESCE(SUM(payout_points),0)").Scan(&paidYTD)

		st := incentive.ComputeSettlement(m.Email, m.Rank, applied, paidYTD, eng)
		if st.PointsCumul == 0 && st.PayoutPoints == 0 {
			continue
		}
		var existing models.QuarterlySettlement
		row := models.QuarterlySettlement{MemberEmail: m.Email, Year: body.Year, Quarter: body.Quarter,
			Rank: m.Rank, Quota: st.Quota, PointsCumul: st.PointsCumul, ExcessPoints: st.ExcessPoints,
			PaidPointsYTD: st.PaidPointsYTD, PayoutPoints: st.PayoutPoints, PayoutAmount: st.PayoutAmount}
		if err := s.db.Where("lower(member_email)=lower(?) AND year=? AND quarter=?", m.Email, body.Year, body.Quarter).First(&existing).Error; err == nil {
			if !existing.Fixed { // never overwrite a fixed row
				row.ID = existing.ID
				s.db.Save(&row)
			}
			row = existing
		} else {
			s.db.Create(&row)
		}
		results = append(results, row)
	}
	s.audit(r, "settlement_run", "settlement", strconv.Itoa(body.Year)+"Q"+strconv.Itoa(body.Quarter), "")
	writeJSON(w, http.StatusOK, results)
}

// handleFixSettlement locks a settlement row (그 차익이 급여로 확정 지급).
func (s *Server) handleFixSettlement(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var st models.QuarterlySettlement
	if err := s.db.First(&st, "id = ?", chi.URLParam(r, "sId")).Error; err != nil {
		writeError(w, http.StatusNotFound, "정산을 찾을 수 없습니다")
		return
	}
	now := time.Now()
	st.Fixed = true
	st.FixedAt = &now
	s.db.Save(&st)
	s.audit(r, "settlement_fix", "settlement", st.ID, "")
	if st.PayoutPoints > 0 {
		s.notify(st.MemberEmail, "settlement",
			fmt.Sprintf("%d년 %d분기 인센티브 정산 확정", st.Year, st.Quarter),
			"이번 분기 인센티브가 확정되었습니다. 내 인센티브에서 확인하세요.", "/incentive")
	}
	writeJSON(w, http.StatusOK, st)
}

// ---- simulation (pure, no persistence) ------------------------------------

type simRequest struct {
	Year    int                       `json:"year"`
	Total   float64                   `json:"total"`
	BE      float64                   `json:"be"`
	Members []incentive.MemberPortion `json:"members"`
	Config  *incentive.Config         `json:"config"` // optional overrides
}

func (s *Server) handleSimulate(w http.ResponseWriter, r *http.Request) {
	if !s.requireAdmin(w, r) {
		return
	}
	var req simRequest
	if err := decodeJSON(r, &req); err != nil {
		writeError(w, http.StatusBadRequest, err.Error())
		return
	}
	_, eng := s.incentiveConfig(yearParam(r))
	if req.Config != nil {
		eng = *req.Config
		if eng.PointRate == 0 {
			eng.PointRate = 1
		}
	}
	stages := incentive.ComputeStages(req.Total, req.BE, eng)
	allocs := incentive.ComputeAllocs(stages, req.Members, eng)
	// per-member point totals
	byMember := map[string]float64{}
	for _, a := range allocs {
		byMember[a.Email] += a.Points
	}
	writeJSON(w, http.StatusOK, map[string]interface{}{
		"stages": stages, "allocs": allocs, "byMember": byMember,
	})
}