package main

import (
	"log"
	"net/http"
	"os"
	"os/signal"
	"syscall"

	apiv1 "git.ar21.de/yolokube/country-geo-locations/api/v1"
	"git.ar21.de/yolokube/country-geo-locations/internal/cache"
	"git.ar21.de/yolokube/country-geo-locations/internal/cmd"
	csvimporter "git.ar21.de/yolokube/country-geo-locations/internal/csv_importer"
	"git.ar21.de/yolokube/country-geo-locations/internal/database"
	"git.ar21.de/yolokube/country-geo-locations/internal/downloader"
	"git.ar21.de/yolokube/country-geo-locations/internal/exporter"
	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/go-chi/render"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
)

func main() {
	cli := cmd.CLI{}
	queue := exporter.NewRequestDataQueue()
	appSettings, err := cli.Parse()
	if err != nil {
		log.Fatal(err)
	}

	handleGracefulShutdown()

	exporterMiddleware := exporter.NewMiddleware(queue)
	r := chi.NewRouter()
	r.Use(middleware.RequestID)
	r.Use(middleware.Logger)
	r.Use(middleware.Recoverer)
	r.Use(exporterMiddleware)
	r.Use(render.SetContentType(render.ContentTypeJSON))

	ctx := downloader.NewContext(appSettings.DataFile, appSettings.DataURL)
	if !ctx.FileExists() {
		if downloadErr := ctx.Download(); downloadErr != nil {
			log.Fatal(downloadErr)
		}
		log.Printf("saved file to %s\n", ctx.Filename)
	}

	cache := cache.NewCache(appSettings.CacheTTL)
	db, err := database.NewDatabase(appSettings)
	if err != nil {
		log.Fatal("database creation failed", err)
	}

	if appSettings.EnableExporter {
		go func() {
			err = enableExporter(appSettings, cache, db, queue)
			if err != nil {
				log.Panic(err)
			}
		}()
		log.Println("prometheus exporter started at", appSettings.ExporterAddress)
	}

	log.Println("importing data from file", appSettings.DataFile)
	err = csvimporter.ImportCSV(appSettings.DataFile, db)
	if err != nil {
		log.Fatal("data Import from file failed", err)
	}
	log.Println("imported data from file successful")

	lh := apiv1.NewLocationHandler(cache, db)
	r.Mount("/api/v1", apiv1.NewRouter(lh))

	server := &http.Server{
		Addr:              appSettings.ServerAddress,
		Handler:           r,
		ReadHeaderTimeout: appSettings.ReadHeaderTimeout,
	}

	log.Println("starting server at", server.Addr)
	if err = server.ListenAndServe(); err != nil {
		log.Panic(err)
	}
}

func enableExporter(
	settings *cmd.AppSettings,
	cache *cache.Cache,
	db *database.Database,
	queue *exporter.RequestDataQueue,
) error {
	prometheus.MustRegister(exporter.NewCollector(settings, cache, db, queue))

	metricsServer := &http.Server{
		Addr:              settings.ExporterAddress,
		Handler:           promhttp.Handler(),
		ReadHeaderTimeout: settings.ReadHeaderTimeout,
	}

	return metricsServer.ListenAndServe()
}

func handleGracefulShutdown() {
	var signals = make(chan os.Signal, 1)

	signal.Notify(signals, syscall.SIGTERM, syscall.SIGINT)

	go func() {
		sig := <-signals
		log.Printf("caught signal: %+v", sig)
		os.Exit(0)
	}()
}