package repository

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"sort"
	"strings"

	"materialanalyzer/internal/model"
)

func LoadProducts(dataDir string) ([]model.Product, error) {
	files, err := os.ReadDir(dataDir)
	if err != nil {
		return nil, fmt.Errorf("read product data dir: %w", err)
	}

	var products []model.Product
	for _, f := range files {
		if f.IsDir() || !strings.EqualFold(filepath.Ext(f.Name()), ".json") {
			continue
		}
		path := filepath.Join(dataDir, f.Name())
		data, err := os.ReadFile(path)
		if err != nil {
			return nil, fmt.Errorf("read %s: %w", path, err)
		}
		var batch []model.Product
		if err := json.Unmarshal(data, &batch); err != nil {
			return nil, fmt.Errorf("parse %s: %w", path, err)
		}
		for _, p := range batch {
			if strings.TrimSpace(p.SKU) == "" {
				continue
			}
			products = append(products, p)
		}
	}

	sort.Slice(products, func(i, j int) bool {
		if products[i].Brand != products[j].Brand {
			return products[i].Brand < products[j].Brand
		}
		return products[i].SKU < products[j].SKU
	})
	return products, nil
}

func FilterProducts(products []model.Product, skuCSV string, limit int) []model.Product {
	wanted := map[string]bool{}
	for _, sku := range strings.Split(skuCSV, ",") {
		sku = strings.TrimSpace(sku)
		if sku != "" {
			wanted[strings.ToLower(sku)] = true
		}
	}

	out := make([]model.Product, 0, len(products))
	for _, p := range products {
		if len(wanted) > 0 && !wanted[strings.ToLower(p.SKU)] {
			continue
		}
		out = append(out, p)
		if limit > 0 && len(out) >= limit {
			break
		}
	}
	return out
}