// backfill-shop-pdd-specs 把指定蝦皮店铺的正式规格补成关联 PDD 的空规格骨架。
// 默认只预览；只有显式传入 --apply 才写数据库。
package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"log"
	"os"
	"strings"
	"time"

	"cmautobuy/admin/config"
	"cmautobuy/admin/repository"
	"cmautobuy/admin/service"
)

type backupFile struct {
	Shop        string       `json:"shop"`
	GeneratedAt string       `json:"generated_at"`
	Items       []backupItem `json:"items"`
}

type backupItem struct {
	PDDGoodsID string `json:"pdd_goods_id"`
	SKUsJSON   string `json:"skus_json"`
}

func main() {
	shop := flag.String("shop", "", "要处理的蝦皮店铺名（精确匹配，必填）")
	apply := flag.Bool("apply", false, "实际写入；不传时只做 dry-run")
	flag.Parse()
	if strings.TrimSpace(*shop) == "" {
		log.Fatal("必须通过 --shop 指定店铺名")
	}

	cfg, err := config.LoadDatabase()
	if err != nil {
		log.Fatalf("读取 MySQL 配置失败: %v", err)
	}
	db, err := repository.OpenMySQL(cfg)
	if err != nil {
		log.Fatalf("连接 MySQL 失败: %v", err)
	}
	defer db.Close()

	sources, err := repository.ListShopSpecSources(db, *shop)
	if err != nil {
		log.Fatal(err)
	}
	now := time.Now()
	plan := service.BuildSpecBackfillPlan(*shop, sources, now)
	if !*apply {
		printReport(plan, 0, "dry-run")
		return
	}
	backupPath, err := writeBackup(plan)
	if err != nil {
		log.Fatalf("创建本机回退备份失败，未写数据库: %v", err)
	}
	updated, err := service.ApplySpecBackfill(db, plan, now)
	if err != nil {
		log.Fatalf("规格回填失败: %v；本机备份位于 %s", err, backupPath)
	}
	printReport(plan, updated, "applied")
	fmt.Printf("本机回退备份：%s\n", backupPath)
}

func printReport(plan service.SpecBackfillPlan, updated int, mode string) {
	summary, _ := json.Marshal(plan.Summary)
	fmt.Printf("模式：%s\n店铺：%s\n蝦皮商品：%d\n候选 PDD：%d\n已回填 PDD：%d\n本次更新 PDD：%d\n分类：%s\n",
		mode, plan.Shop, plan.SourceProductCount, plan.CandidatePDDCount,
		plan.BackfilledPDDCount, updated, summary)
}

func writeBackup(plan service.SpecBackfillPlan) (string, error) {
	file, err := os.CreateTemp("", "cmautobuy_spec_backfill_backup_*.json")
	if err != nil {
		return "", err
	}
	path := file.Name()
	defer file.Close()
	if err := file.Chmod(0o600); err != nil {
		return "", err
	}
	backup := backupFile{Shop: plan.Shop, GeneratedAt: time.Now().UTC().Format(time.RFC3339)}
	for _, candidate := range plan.Candidates {
		backup.Items = append(backup.Items, backupItem{PDDGoodsID: candidate.PDDGoodsID, SKUsJSON: candidate.OriginalSKUsJSON})
	}
	encoder := json.NewEncoder(file)
	encoder.SetIndent("", "  ")
	if err := encoder.Encode(backup); err != nil {
		return "", err
	}
	return path, nil
}