//go:generate go install github.com/valyala/quicktemplate/qtc@latest
//go:generate qtc -dir=web/template
//go:generate go install golang.org/x/text/cmd/gotext@latest
//go:generate gotext -srclang=en update -out=catalog_gen.go -lang=en,ru
package main

import (
	"context"
	"errors"
	"flag"
	"log"
	"net"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"runtime/pprof"
	"syscall"
	"time"

	"github.com/caarlos0/env/v10"
	"golang.org/x/text/language"
	"golang.org/x/text/message"

	"source.toby3d.me/toby3d/home/internal/common"
	"source.toby3d.me/toby3d/home/internal/domain"
	pagefsrepo "source.toby3d.me/toby3d/home/internal/page/repository/fs"
	pageucase "source.toby3d.me/toby3d/home/internal/page/usecase"
	sitefsrepo "source.toby3d.me/toby3d/home/internal/site/repository/fs"
	siteucase "source.toby3d.me/toby3d/home/internal/site/usecase"
	"source.toby3d.me/toby3d/home/web/template"
)

var (
	config = new(domain.Config)
	logger = log.New(os.Stdout, "home\t", log.Lmsgprefix|log.LstdFlags|log.LUTC)
)

var cpuProfilePath, memProfilePath string

func init() {
	flag.StringVar(&cpuProfilePath, "cpuprofile", "", "set path to saving CPU memory profile")
	flag.StringVar(&memProfilePath, "memprofile", "", "set path to saving pprof memory profile")
	flag.Parse()

	var err error
	if err = env.ParseWithOptions(config, env.Options{Prefix: "HOME_"}); err != nil {
		logger.Fatalln("cannot unmarshal configuration into domain:", err)
	}

	if config.ContentDir, err = filepath.Abs(filepath.Clean(config.ContentDir)); err != nil {
		logger.Fatalf("cannot format '%s' content dir path into absolute path: %s", config.ContentDir, err)
	}

	if _, err = os.Stat(config.ContentDir); err != nil {
		if errors.Is(err, os.ErrExist) {
			return
		}

		if !errors.Is(err, os.ErrNotExist) {
			logger.Fatalln("cannot check directory path for content:", err)
		}

		if err = os.MkdirAll(config.ContentDir, os.ModePerm); err != nil {
			logger.Fatalln("cannot create directory for content:", err)
		}
	}
}

func main() {
	ctx := context.Background()
	matcher := language.NewMatcher(message.DefaultCatalog.Languages())

	contentDir := os.DirFS(config.ContentDir)

	sites := sitefsrepo.NewFileSystemSiteRepository(contentDir)
	siter := siteucase.NewSiteUseCase(sites)

	pages := pagefsrepo.NewFileSystemPageRepository(contentDir)
	pager := pageucase.NewPageUseCase(pages)

	server := &http.Server{
		Addr: config.AddrPort().String(),
		Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			tags, _, err := language.ParseAcceptLanguage(r.Header.Get(common.HeaderAcceptLanguage))
			if err != nil || len(tags) == 0 {
				tags = append(tags, language.English)
			}

			lang, _, _ := matcher.Match(tags...)

			site, err := siter.Do(r.Context(), lang)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)

				return
			}

			page, err := pager.Do(r.Context(), lang, r.URL.Path)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)

				return
			}

			w.Header().Set(common.HeaderContentType, common.MIMETextHTMLCharsetUTF8)
			template.WriteTemplate(w, template.NewPage(template.NewBaseOf(site), page))
		}),
		ErrorLog:     logger,
		BaseContext:  func(ln net.Listener) context.Context { return ctx },
		WriteTimeout: 500 * time.Millisecond,
	}

	done := make(chan os.Signal, 1)
	signal.Notify(done, os.Interrupt, syscall.SIGINT, syscall.SIGTERM)

	if cpuProfilePath != "" {
		cpuProfile, err := os.Create(cpuProfilePath)
		if err != nil {
			logger.Fatalln("could not create CPU profile:", err)
		}
		defer cpuProfile.Close()

		if err = pprof.StartCPUProfile(cpuProfile); err != nil {
			logger.Fatalln("could not start CPU profile:", err)
		}
		defer pprof.StopCPUProfile()
	}

	go func(server *http.Server) {
		logger.Printf("starting server on %d...", config.Port)

		if err := server.ListenAndServe(); err != nil {
			logger.Fatalln("cannot listen and serve server:", err)
		}
	}(server)

	<-done

	if err := server.Shutdown(ctx); err != nil {
		logger.Fatalln("failed shutdown server:", err)
	}

	if memProfilePath == "" {
		return
	}

	memProfile, err := os.Create(memProfilePath)
	if err != nil {
		logger.Fatalln("could not create memory profile:", err)
	}
	defer memProfile.Close()

	runtime.GC() // NOTE(toby3d): get up-to-date statistics

	if err = pprof.WriteHeapProfile(memProfile); err != nil {
		logger.Fatalln("could not write memory profile:", err)
	}
}