package routes

import (
	"bssapp-backend/queries"
	"bssapp-backend/utils"
	"database/sql"
	"encoding/json"
	"net/http"
	"strconv"
	"strings"
)

// Step-1/2 scope (distinct+cascade) comes from the PostgreSQL parameter cache.
// For now we implement:
// - Postgres tables (bootstrap)
// - List/Save rules (bulk)
// - Options endpoint for cascade (mk_urunpricingprmtr)

type PricingRuleBulkSavePayload struct {
	Items []queries.PricingRuleSaveItem `json:"items"`
}

func GetPricingRulesHandler(pg *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")
		traceID := utils.TraceIDFromRequest(r)
		ctx := utils.ContextWithTraceID(r.Context(), traceID)

		rows, err := queries.ListPricingRules(ctx, pg)
		if err != nil {
			http.Error(w, "pricing rules list error", http.StatusInternalServerError)
			return
		}
		_ = json.NewEncoder(w).Encode(rows)
	}
}

// Very small “bulk upsert” for step-1/2: we only need to persist the multipliers+roundings for now.
// Rules are identified by UUID; new rows can be created via empty id (server generates).
func SavePricingRulesBulkHandler(pg *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")

		var payload PricingRuleBulkSavePayload
		if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
			http.Error(w, "invalid payload", http.StatusBadRequest)
			return
		}

		traceID := utils.TraceIDFromRequest(r)
		ctx := utils.ContextWithTraceID(r.Context(), traceID)

		tx, err := pg.BeginTx(ctx, nil)
		if err != nil {
			http.Error(w, "pg transaction start error", http.StatusInternalServerError)
			return
		}
		defer tx.Rollback()

		updated := 0
		for _, it := range payload.Items {
			// Zero means that no rounding rule has been configured yet.
			if it.TryStep < 0 || it.UsdStep < 0 || it.EurStep < 0 {
				http.Error(w, "invalid rounding step", http.StatusBadRequest)
				return
			}
			id, err := queries.UpsertPricingRule(ctx, tx, it)
			if err != nil {
				http.Error(w, "pricing rule save error", http.StatusInternalServerError)
				return
			}
			if id != "" {
				updated++
			}
		}

		if err := tx.Commit(); err != nil {
			http.Error(w, "pg transaction commit error", http.StatusInternalServerError)
			return
		}
		_ = json.NewEncoder(w).Encode(map[string]any{"success": true, "updated": updated})
	}
}

func GetPricingRuleOptionsHandler(pg *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")

		field := strings.TrimSpace(r.URL.Query().Get("field"))
		if field == "" {
			http.Error(w, "missing field", http.StatusBadRequest)
			return
		}

		limit := 500
		if raw := strings.TrimSpace(r.URL.Query().Get("limit")); raw != "" {
			if n, err := strconv.Atoi(raw); err == nil && n > 0 && n <= 5000 {
				limit = n
			}
		}

		f := pricingRuleFiltersFromRequest(r)

		traceID := utils.TraceIDFromRequest(r)
		ctx := utils.ContextWithTraceID(r.Context(), traceID)

		opts, err := queries.ListPricingParameterDistinctOptions(ctx, pg, field, f, limit)
		if err != nil {
			http.Error(w, "options lookup error", http.StatusInternalServerError)
			return
		}

		_ = json.NewEncoder(w).Encode(map[string]any{
			"field":   field,
			"options": opts,
		})
	}
}

func GetPricingParameterRulesHandler(pg *sql.DB) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json; charset=utf-8")

		traceID := utils.TraceIDFromRequest(r)
		ctx := utils.ContextWithTraceID(r.Context(), traceID)
		rows, err := queries.ListPricingParameterRules(ctx, pg, pricingRuleFiltersFromRequest(r))
		if err != nil {
			http.Error(w, "pricing parameter rules list error", http.StatusInternalServerError)
			return
		}
		_ = json.NewEncoder(w).Encode(rows)
	}
}

func pricingRuleFiltersFromRequest(r *http.Request) queries.PricingRuleOptionFilters {
	return queries.PricingRuleOptionFilters{
		AskiliYan:     splitCSV(r.URL.Query().Get("askili_yan")),
		Kategori:      splitCSV(r.URL.Query().Get("kategori")),
		UrunIlkGrubu:  splitCSV(r.URL.Query().Get("urun_ilk_grubu")),
		UrunAnaGrubu:  splitCSV(r.URL.Query().Get("urun_ana_grubu")),
		UrunAltGrubu:  splitCSV(r.URL.Query().Get("urun_alt_grubu")),
		Icerik:        splitCSV(r.URL.Query().Get("icerik")),
		Marka:         splitCSV(r.URL.Query().Get("marka")),
		BrandCode:     splitCSV(r.URL.Query().Get("brand_code")),
		BrandGroupSec: splitCSV(r.URL.Query().Get("brand_group")),
	}
}

func splitCSV(raw string) []string {
	raw = strings.TrimSpace(raw)
	if raw == "" {
		return nil
	}
	parts := strings.Split(raw, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p != "" {
			out = append(out, p)
		}
	}
	return out
}