package main

import (
	"context"
	"database/sql"
	"errors"
	"flag"
	"fmt"
	"os"
	"time"

	"github.com/go-sql-driver/mysql"
	"lingniu/vehicle-data-platform/apps/api/internal/gzev"
)

func main() {
	if err := run(); err != nil {
		fmt.Fprintln(os.Stderr, "gzev-daily-report:", err)
		os.Exit(1)
	}
}
func run() error {
	preview := flag.Bool("preview", false, "print summary without sending or recording delivery")
	flag.Parse()
	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
	defer cancel()
	cfg, err := mysql.ParseDSN(os.Getenv("MYSQL_DSN"))
	if err != nil {
		return errors.New("invalid MYSQL_DSN")
	}
	cfg.ParseTime = true
	cfg.Loc = time.UTC
	cfg.Timeout = 10 * time.Second
	cfg.ReadTimeout = 30 * time.Second
	db, err := sql.Open("mysql", cfg.FormatDSN())
	if err != nil {
		return errors.New("cannot initialize MySQL")
	}
	defer db.Close()
	account := env("GZEV_ACCOUNT", "guangdonglingniu")
	report, err := gzev.LoadDailyReport(ctx, db, account, env("GZEV_START_DATE", "2024-01-01"), time.Now())
	if err != nil {
		return err
	}
	title, body := report.Message()
	if *preview {
		fmt.Println(title + "\n\n" + body)
		return nil
	}
	sender := gzev.ServerChanFromEnv()
	sent, err := gzev.DeliverDailyReport(env("GZEV_DAILY_REPORT_STATE", "/var/lib/lingniu-gzev/daily-report.json"), report.Date, func() error { return sender.SendMessage(ctx, title, body) })
	if err != nil {
		return err
	}
	if sent {
		fmt.Printf("ServerChan accepted daily report: date=%s fetched_days=%d expected_days=%d missing_dates=%d\n", report.Date, report.Fetched, report.Expected, len(report.Missing))
	} else {
		fmt.Printf("Daily report already accepted; skipped duplicate: date=%s\n", report.Date)
	}
	return nil
}
func env(k, fallback string) string {
	if v := os.Getenv(k); v != "" {
		return v
	}
	return fallback
}