package main

import (
	"flag"
	"log"
	"net/http"
	"os"
)

func addServerHeaders(serverName string) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Add("Server", serverName)
			next.ServeHTTP(w, r)
		})
	}
}

func logging(logger *log.Logger) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			logger.Printf("%s %s %s", r.Method, r.URL.Path, r.RemoteAddr)
			next.ServeHTTP(w, r)
		})
	}
}

func main() {
	// TODO: Use slog instead
	logger := log.New(os.Stderr, "gos3dir: ", log.LstdFlags)

	flag.Parse()
	if flag.NArg() == 0 {
		logger.Fatalf("Pass directory name: gos3dir [path]")
		os.Exit(1)
	}

	rootDir := flag.Arg(0)
	if info, err := os.Stat(rootDir); err != nil {
		logger.Fatalf("Error accessing root directory %q: %v", rootDir, err)
	} else if !info.IsDir() {
		logger.Fatalf("Path %q is not a directory", rootDir)
	}
	logger.Printf("Using root directory: %s", rootDir)

	srv := &server{rootDir: rootDir, logger: logger}

	// TODO: Support virtual addressing style https://docs.aws.amazon.com/cli/latest/topic/s3-config.html#addressing-style
	// for now it assumes path style
	http.HandleFunc("GET /{$}", srv.ls)
	http.HandleFunc("GET /{bucket}", srv.ls)
	http.HandleFunc("GET /{bucket}/{key...}", srv.cpGet)
	http.HandleFunc("PUT /{bucket}", srv.mb)
	http.HandleFunc("PUT /{bucket}/{key...}", srv.cpPut)
	http.HandleFunc("DELETE /{bucket}", srv.rb)
	http.HandleFunc("DELETE /{bucket}/{key...}", srv.rm)

	handler := addServerHeaders("gos3dir")(logging(logger)(http.DefaultServeMux))

	logger.Print("Server listening on :8041...")
	// TODO: Graceful shutdown
	if err := http.ListenAndServe(":8041", handler); err != nil {
		logger.Fatal(err)
	}
}