// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// Daemon identityd is an HTTP server that uses OAuth to create
// security.Blessings objects.
//
// For more information on its design see:
// https://v.io/designdocs/identity-service.html
package main

import (
	"database/sql"
	"flag"
	"fmt"
	"os"
	"time"

	"v.io/v23"
	"v.io/x/lib/vlog"

	_ "v.io/x/ref/runtime/factories/static"
	"v.io/x/ref/services/identity/internal/auditor"
	"v.io/x/ref/services/identity/internal/blesser"
	"v.io/x/ref/services/identity/internal/caveats"
	"v.io/x/ref/services/identity/internal/oauth"
	"v.io/x/ref/services/identity/internal/revocation"
	"v.io/x/ref/services/identity/internal/server"
)

var (
	// Configuration for various Google OAuth-based clients.
	googleConfigWeb     = flag.String("google-config-web", "", "Path to JSON-encoded OAuth client configuration for the web application that renders the audit log for blessings provided by this provider.")
	googleConfigChrome  = flag.String("google-config-chrome", "", "Path to the JSON-encoded OAuth client configuration for Chrome browser applications that obtain blessings from this server (via the OAuthBlesser.BlessUsingAccessToken RPC) from this server.")
	googleConfigAndroid = flag.String("google-config-android", "", "Path to the JSON-encoded OAuth client configuration for Android applications that obtain blessings from this server (via the OAuthBlesser.BlessUsingAccessToken RPC) from this server.")

	// Flags controlling the HTTP server
	externalHttpAddr = flag.String("external-http-addr", "", "External address on which the HTTP server listens on. If none is provided the server will only listen on -http-addr.")
	httpAddr         = flag.String("http-addr", "localhost:8125", "Address on which the HTTP server listens on.")
	tlsConfig        = flag.String("tls-config", "", "Comma-separated list of TLS certificate and private key files, in that order. This must be provided.")
	assetsPrefix     = flag.String("assets-prefix", "", "host serving the web assets for the identity server")
	mountPrefix      = flag.String("mount-prefix", "identity", "mount name prefix to use. May be rooted.")
)

func main() {
	flag.Usage = usage
	ctx, shutdown := v23.Init()
	defer shutdown()

	var sqlDB *sql.DB
	var err error
	if len(*sqlConf) > 0 {
		if sqlDB, err = dbFromConfigFile(*sqlConf); err != nil {
			vlog.Fatalf("failed to create sqlDB: %v", err)
		}
	}

	googleoauth, err := oauth.NewGoogleOAuth(*googleConfigWeb)
	if err != nil {
		vlog.Fatalf("Failed to setup GoogleOAuth: %v", err)
	}

	auditor, reader, err := auditor.NewSQLBlessingAuditor(sqlDB)
	if err != nil {
		vlog.Fatalf("Failed to create sql auditor from config: %v", err)
	}

	revocationManager, err := revocation.NewRevocationManager(sqlDB)
	if err != nil {
		vlog.Fatalf("Failed to start RevocationManager: %v", err)
	}

	listenSpec := v23.GetListenSpec(ctx)
	s := server.NewIdentityServer(
		googleoauth,
		auditor,
		reader,
		revocationManager,
		googleOAuthBlesserParams(googleoauth, revocationManager),
		caveats.NewBrowserCaveatSelector(*assetsPrefix),
		*assetsPrefix,
		*mountPrefix)
	s.Serve(ctx, &listenSpec, *externalHttpAddr, *httpAddr, *tlsConfig)
}

func usage() {
	fmt.Fprintf(os.Stderr, `%s starts an HTTP server that brokers blessings after authenticating through OAuth.

To generate TLS certificates so the HTTP server can use SSL:
go run $(go list -f {{.Dir}} "crypto/tls")/generate_cert.go --host <IP address>

To use Google as an OAuth provider the --google-config-* flags must be set to point to
the a JSON file obtained after registering the application with the Google Developer Console
at https://cloud.google.com/console

More details on Google OAuth at:
https://developers.google.com/accounts/docs/OAuth2Login

Flags:
`, os.Args[0])
	flag.PrintDefaults()
}

func googleOAuthBlesserParams(oauthProvider oauth.OAuthProvider, revocationManager revocation.RevocationManager) blesser.OAuthBlesserParams {
	params := blesser.OAuthBlesserParams{
		OAuthProvider:     oauthProvider,
		BlessingDuration:  365 * 24 * time.Hour,
		RevocationManager: revocationManager,
	}
	if clientID, err := getOAuthClientID(*googleConfigChrome); err != nil {
		vlog.Info(err)
	} else {
		params.AccessTokenClients = append(params.AccessTokenClients, oauth.AccessTokenClient{Name: "chrome", ClientID: clientID})
	}
	if clientID, err := getOAuthClientID(*googleConfigAndroid); err != nil {
		vlog.Info(err)
	} else {
		params.AccessTokenClients = append(params.AccessTokenClients, oauth.AccessTokenClient{Name: "android", ClientID: clientID})
	}
	return params
}

func getOAuthClientID(configFile string) (clientID string, err error) {
	f, err := os.Open(configFile)
	if err != nil {
		return "", fmt.Errorf("failed to open %q: %v", configFile, err)
	}
	defer f.Close()
	clientID, err = oauth.ClientIDFromJSON(f)
	if err != nil {
		return "", fmt.Errorf("failed to decode JSON in %q: %v", configFile, err)
	}
	return clientID, nil
}