package main

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	_ "github.com/go-sql-driver/mysql"

	"lingniu/vehicle-data-platform/apps/api/internal/config"
	"lingniu/vehicle-data-platform/apps/api/internal/platform"
)

func main() {
	if err := run(); err != nil {
		log.Fatal(err)
	}
}

func run() error {
	cfg := config.Load()
	if strings.TrimSpace(cfg.MySQLDSN) == "" {
		return fmt.Errorf("MYSQL_DSN is required")
	}
	gateways := map[string]platform.AlertNotificationGateway{}
	for _, candidate := range []struct {
		channel  string
		endpoint string
		secret   string
	}{
		{channel: "sms", endpoint: cfg.AlertNotificationSMSURL, secret: cfg.AlertNotificationSMSSecret},
		{channel: "email", endpoint: cfg.AlertNotificationEmailURL, secret: cfg.AlertNotificationEmailSecret},
		{channel: "wecom", endpoint: cfg.AlertNotificationWeComURL, secret: cfg.AlertNotificationWeComSecret},
	} {
		if strings.TrimSpace(candidate.endpoint) == "" && strings.TrimSpace(candidate.secret) == "" {
			continue
		}
		gateway, err := platform.NewHTTPAlertNotificationGateway(candidate.endpoint, candidate.secret, cfg.AlertNotificationTimeout)
		if err != nil {
			return fmt.Errorf("%s gateway: %w", candidate.channel, err)
		}
		gateways[candidate.channel] = gateway
	}
	if len(gateways) == 0 {
		return fmt.Errorf("at least one ALERT_NOTIFICATION_*_URL and matching signing secret are required")
	}
	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()
	db, err := platform.OpenSQL(ctx, "mysql", cfg.MySQLDSN)
	if err != nil {
		return err
	}
	defer db.Close()
	host, _ := os.Hostname()
	dispatcher := platform.NewAlertNotificationDispatcher(
		platform.NewProductionStore(db, nil, ""),
		gateways,
		cfg.AlertNotificationBatchSize,
		cfg.AlertNotificationLease,
		"notification-dispatcher-"+host,
	)
	poll := cfg.AlertNotificationPollInterval
	if poll < 250*time.Millisecond {
		poll = time.Second
	}
	if poll > time.Minute {
		poll = time.Minute
	}
	ticker := time.NewTicker(poll)
	defer ticker.Stop()
	log.Printf("alert notification dispatcher started channels=%d batch=%d poll=%s lease=%s", len(gateways), cfg.AlertNotificationBatchSize, poll, cfg.AlertNotificationLease)
	for {
		started := time.Now()
		result, dispatchErr := dispatcher.RunOnce(ctx)
		if dispatchErr != nil {
			log.Printf("alert notification dispatch failed claimed=%d sent=%d failed=%d duration=%s error=%v", result.Claimed, result.Sent, result.Failed, time.Since(started), dispatchErr)
		} else if result.Claimed > 0 {
			log.Printf("alert notification dispatch completed claimed=%d sent=%d failed=%d duration=%s", result.Claimed, result.Sent, result.Failed, time.Since(started))
		}
		select {
		case <-ctx.Done():
			log.Printf("alert notification dispatcher stopped")
			return nil
		case <-ticker.C:
		}
	}
}