// Copyright 2024 OpenPubkey
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0

package providers

import (
	"context"
	"net/http"

	"time"

	"github.com/openpubkey/openpubkey/discover"
	"github.com/openpubkey/openpubkey/providers/mocks"
)

const googleIssuer = "https://accounts.google.com"

// GoogleOptions is an options struct that configures how providers.GoogleOp
// operates. See providers.GetDefaultGoogleOpOptions for the recommended default
// values to use when interacting with Google as the OpenIdProvider.
type GoogleOptions struct {
	// ClientID is the client ID of the OIDC application. It should be the
	// expected "aud" claim in received ID tokens from the OP.
	ClientID string
	// ClientSecret is the client secret of the OIDC application. Some OPs do
	// not require that this value is set.
	ClientSecret string
	// Issuer is the OP's issuer URI for performing OIDC authorization and
	// discovery.
	Issuer string
	// Scopes is the list of scopes to send to the OP in the initial
	// authorization request.
	Scopes []string
	// PromptType is the type of prompt to use when requesting authorization from the user. Typically
	// this is set to "consent".
	PromptType string
	// AccessType is the type of access to request from the OP. Typically this is set to "offline".
	AccessType string
	// RedirectURIs is the list of authorized redirect URIs that can be
	// redirected to by the OP after the user completes the authorization code
	// flow exchange. Ensure that your OIDC application is configured to accept
	// these URIs otherwise an error may occur.
	RedirectURIs []string
	// RemoteRedirectURI is an optional redirect URI to use. If set, this overrides the
	// RedirectURIs value sent to the OP during authorization. We still open a
	// localhost URI expecting the remote server to proxy the request to a localhost port.
	RemoteRedirectURI string
	// GQSign denotes if the received ID token should be upgraded to a GQ token
	// using GQ signatures.
	GQSign bool
	// OpenBrowser denotes if the client's default browser should be opened
	// automatically when performing the OIDC authorization flow. This value
	// should typically be set to true, unless performing some headless
	// automation (e.g. integration tests) where you don't want the browser to
	// open.
	OpenBrowser bool
	// HttpClient is the http.Client to use when making queries to the OP (OIDC
	// code exchange, refresh, verification of ID token, fetch of JWKS endpoint,
	// etc.). If nil, then http.DefaultClient is used.
	HttpClient *http.Client
	// IssuedAtOffset configures the offset to add when validating the "iss" and
	// "exp" claims of received ID tokens from the OP.
	IssuedAtOffset time.Duration
}

func GetDefaultGoogleOpOptions() *GoogleOptions {
	return &GoogleOptions{
		Issuer:   googleIssuer,
		ClientID: "206584157355-7cbe4s640tvm7naoludob4ut1emii7sf.apps.googleusercontent.com",
		// The clientSecret was intentionally checked in. It holds no power. Do not report as a security issue
		// Google requires a ClientSecret even if this a public OIDC App
		ClientSecret: "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", // The client secret is a public value
		Scopes:       []string{"openid profile email"},
		PromptType:   "consent",
		AccessType:   "offline",
		RedirectURIs: []string{
			"http://localhost:3000/login-callback",
			"http://localhost:10001/login-callback",
			"http://localhost:11110/login-callback",
		},
		GQSign:         false,
		OpenBrowser:    true,
		HttpClient:     nil,
		IssuedAtOffset: 1 * time.Minute,
	}
}

// NewGoogleOp creates a Google OP (OpenID Provider) using the
// default configurations options. It uses the OIDC Relying Party (Client)
// setup by the OpenPubkey project.
func NewGoogleOp() BrowserOpenIdProvider {
	options := GetDefaultGoogleOpOptions()
	return NewGoogleOpWithOptions(options)
}

// NewGoogleOpWithOptions creates a Google OP with configuration specified
// using an options struct. This is useful if you want to use your own OIDC
// Client or override the configuration.
func NewGoogleOpWithOptions(opts *GoogleOptions) BrowserOpenIdProvider {
	return &GoogleOp{
		StandardOp{
			clientID:                  opts.ClientID,
			ClientSecret:              opts.ClientSecret,
			Scopes:                    opts.Scopes,
			PromptType:                opts.PromptType,
			AccessType:                opts.AccessType,
			RedirectURIs:              opts.RedirectURIs,
			RemoteRedirectURI:         opts.RemoteRedirectURI,
			GQSign:                    opts.GQSign,
			OpenBrowser:               opts.OpenBrowser,
			HttpClient:                opts.HttpClient,
			IssuedAtOffset:            opts.IssuedAtOffset,
			issuer:                    opts.Issuer,
			requestTokensOverrideFunc: nil,
			publicKeyFinder: discover.PublicKeyFinder{
				JwksFunc: func(ctx context.Context, issuer string) ([]byte, error) {
					return discover.GetJwksByIssuer(ctx, issuer, opts.HttpClient)
				},
			},
		},
	}
}

type GoogleOp = StandardOpRefreshable

var _ OpenIdProvider = (*GoogleOp)(nil)
var _ BrowserOpenIdProvider = (*GoogleOp)(nil)
var _ RefreshableOpenIdProvider = (*GoogleOp)(nil)

func CreateMockGoogleOpWithOpts(googleOpOpts *GoogleOptions, userActions mocks.UserBrowserInteractionMock) (RefreshableOpenIdProvider, error) {
	subjects := []mocks.Subject{
		{
			SubjectID: "alice@gmail.com",
		},
	}

	idp, err := mocks.NewMockOp(googleOpOpts.Issuer, subjects)
	if err != nil {
		return nil, err
	}

	expSigningKey, expKeyID, expRecord := idp.RandomSigningKey()
	idp.MockProviderBackend.IDTokenTemplate = &mocks.IDTokenTemplate{
		CommitFunc:           mocks.AddNonceCommit,
		Issuer:               googleOpOpts.Issuer,
		Nonce:                "empty",
		NoNonce:              false,
		Aud:                  googleOpOpts.ClientID,
		KeyID:                expKeyID,
		NoKeyID:              false,
		Alg:                  expRecord.Alg,
		NoAlg:                false,
		ExtraClaims:          map[string]any{"extraClaim": "extraClaimValue"},
		ExtraProtectedClaims: map[string]any{"extraHeader": "extraheaderValue"},
		SigningKey:           expSigningKey,
	}

	rt := idp.GetHTTPClient()
	googleOpOpts.HttpClient = rt
	googleOpOpts.OpenBrowser = false // Don't open the browser in tests

	googOp := NewGoogleOpWithOptions(googleOpOpts)

	browserOpenOverrideFn := userActions.BrowserOpenOverrideFunc(idp)
	op := googOp.(*StandardOpRefreshable)
	op.SetOpenBrowserOverride(browserOpenOverrideFn)

	return op, nil
}
