// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package main

import (
	"context"
	"fmt"
	"net/http"
	"os"

	"cloud.google.com/go/compute/metadata"
	"cloud.google.com/go/datastore"
)

var log = newStdLogger()

func main() {
	s, err := newServer(func(s *server) error {
		pid := projectID()
		if pid == "" {
			s.db = &inMemStore{}
		} else {
			c, err := datastore.NewClient(context.Background(), pid)
			if err != nil {
				return fmt.Errorf("could not create cloud datastore client: %v", err)
			}
			s.db = cloudDatastore{client: c}
		}
		s.log = log
		return nil
	})
	if err != nil {
		log.Fatalf("Error creating server: %v", err)
	}
	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}
	log.Printf("Listening on :%v ...", port)
	log.Fatalf("Error listening on :%v: %v", port, http.ListenAndServe(":"+port, s))
}

func projectID() string {
	id := os.Getenv("DATASTORE_PROJECT_ID")
	if id != "" {
		return id
	}
	id, err := metadata.ProjectID()
	if err != nil && os.Getenv("GAE_INSTANCE") != "" {
		log.Fatalf("Could not determine the project ID: %v", err)
	}
	return id
}