package main

import (
	"encoding/json"
	"errors"
	"net/http"
	"time"

	"git.k6n.net/mats/go-redis-inventory/pkg/inventory"
)

type reservationLineReq struct {
	SKU        string `json:"sku"`
	LocationID string `json:"locationId"`
	Quantity   uint32 `json:"quantity"`
}

type reservationBatchReq struct {
	HolderID   string               `json:"holderId"`
	TTLSeconds int64                `json:"ttlSeconds,omitempty"`
	Lines      []reservationLineReq `json:"lines"`
}

func (srv *Server) reserveInventoryHandler(w http.ResponseWriter, r *http.Request) {
	var req reservationBatchReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		return
	}
	if req.HolderID == "" {
		http.Error(w, "missing holderId", http.StatusBadRequest)
		return
	}
	if len(req.Lines) == 0 {
		http.Error(w, "missing lines", http.StatusBadRequest)
		return
	}
	ttl := 15 * time.Minute
	if req.TTLSeconds > 0 {
		ttl = time.Duration(req.TTLSeconds) * time.Second
	}
	for _, line := range req.Lines {
		if line.SKU == "" || line.LocationID == "" || line.Quantity == 0 {
			http.Error(w, "each line must include sku, locationId, and quantity", http.StatusBadRequest)
			return
		}
		if err := srv.reservationService.ReserveForCart(r.Context(), inventory.CartReserveRequest{
			InventoryReference: &inventory.InventoryReference{
				SKU:        inventory.SKU(line.SKU),
				LocationID: inventory.LocationID(line.LocationID),
			},
			CartID:   inventory.CartID(req.HolderID),
			Quantity: line.Quantity,
			TTL:      ttl,
		}); err != nil {
			status := http.StatusInternalServerError
			if errors.Is(err, inventory.ErrInsufficientInventory) {
				status = http.StatusConflict
			}
			http.Error(w, err.Error(), status)
			return
		}
	}
	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(map[string]any{"status": "reserved", "holderId": req.HolderID})
}

func (srv *Server) releaseReservationHandler(w http.ResponseWriter, r *http.Request) {
	var req reservationBatchReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		http.Error(w, "invalid request body", http.StatusBadRequest)
		return
	}
	if req.HolderID == "" {
		http.Error(w, "missing holderId", http.StatusBadRequest)
		return
	}
	if len(req.Lines) == 0 {
		http.Error(w, "missing lines", http.StatusBadRequest)
		return
	}
	for _, line := range req.Lines {
		if line.SKU == "" || line.LocationID == "" {
			http.Error(w, "each line must include sku and locationId", http.StatusBadRequest)
			return
		}
		if err := srv.reservationService.ReleaseForCart(r.Context(),
			inventory.SKU(line.SKU),
			inventory.LocationID(line.LocationID),
			inventory.CartID(req.HolderID),
		); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}
	w.Header().Set("Content-Type", "application/json")
	_ = json.NewEncoder(w).Encode(map[string]any{"status": "released", "holderId": req.HolderID})
}