/*
Copyright 2022 Gravitational, Inc.

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.
*/

package database

import (
	"context"
	"crypto/tls"
	"crypto/x509/pkix"
	"errors"
	"strconv"
	"testing"
	"time"

	"github.com/gravitational/trace"
	"github.com/jackc/pgconn"
	"github.com/jackc/pgerrcode"
	"github.com/stretchr/testify/require"

	"github.com/gravitational/teleport/api/client/proto"
	"github.com/gravitational/teleport/api/types"
	"github.com/gravitational/teleport/lib/fixtures"
	"github.com/gravitational/teleport/lib/srv/db/common"
	"github.com/gravitational/teleport/lib/srv/db/postgres"
	"github.com/gravitational/teleport/lib/tlsca"
)

func TestPostgresErrors(t *testing.T) {
	p := PostgresPinger{}

	for _, tt := range []struct {
		name     string
		pingErr  error
		errCheck require.ErrorAssertionFunc
	}{
		{
			name:    "connection refused error",
			pingErr: errors.New("failed to connect to `host=127.0.0.1 user=postgres database=postgres`: server error (: connection refused (SQLSTATE ))"),
			errCheck: func(tt require.TestingT, err error, i ...interface{}) {
				require.True(tt, p.IsConnectionRefusedError(err))
			},
		},
		{
			name: "invalid database error",
			pingErr: &pgconn.PgError{
				Code: pgerrcode.InvalidCatalogName,
			},
			errCheck: func(tt require.TestingT, err error, i ...interface{}) {
				require.True(tt, p.IsInvalidDatabaseNameError(err))
			},
		},
		{
			name: "invalid user error",
			pingErr: &pgconn.PgError{
				Code: pgerrcode.InvalidAuthorizationSpecification,
			},
			errCheck: func(tt require.TestingT, err error, i ...interface{}) {
				require.True(tt, p.IsInvalidDatabaseUserError(err))
			},
		},
	} {
		t.Run(tt.name, func(t *testing.T) {
			tt.errCheck(t, tt.pingErr)
		})
	}
}

// mockClient is a mock that implements AuthClient interface.

type mockClient struct {
	common.AuthClientCA

	ca types.CertAuthority
}

func setupMockClient(t *testing.T) *mockClient {
	t.Helper()

	_, cert, err := tlsca.GenerateSelfSignedCA(pkix.Name{CommonName: "example.com"}, nil, time.Minute)
	require.NoError(t, err)

	ca, err := types.NewCertAuthority(types.CertAuthoritySpecV2{
		Type:        types.HostCA,
		ClusterName: "example.com",
		ActiveKeys: types.CAKeySet{
			SSH: []*types.SSHKeyPair{{PublicKey: []byte("SSH CA cert")}},
			TLS: []*types.TLSKeyPair{{Cert: cert}},
		},
	})
	require.NoError(t, err)

	return &mockClient{
		ca: ca,
	}
}

func (c *mockClient) GenerateDatabaseCert(ctx context.Context, req *proto.DatabaseCertRequest) (*proto.DatabaseCertResponse, error) {
	csr, err := tlsca.ParseCertificateRequestPEM(req.CSR)
	if err != nil {
		return nil, trace.Wrap(err)
	}
	tlsCACert, err := tls.X509KeyPair([]byte(fixtures.TLSCACertPEM), []byte(fixtures.TLSCAKeyPEM))
	if err != nil {
		return nil, trace.Wrap(err)
	}
	tlsCA, err := tlsca.FromTLSCertificate(tlsCACert)
	if err != nil {
		return nil, trace.Wrap(err)
	}

	certReq := tlsca.CertificateRequest{
		PublicKey: csr.PublicKey,
		Subject:   csr.Subject,
		NotAfter:  time.Now().Add(req.TTL.Get()),
		DNSNames:  req.ServerNames,
	}
	cert, err := tlsCA.GenerateCertificate(certReq)
	if err != nil {
		return nil, trace.Wrap(err)
	}
	return &proto.DatabaseCertResponse{
		Cert: cert,
		CACerts: [][]byte{
			[]byte(fixtures.TLSCACertPEM),
		},
	}, nil
}

func (c *mockClient) GetCertAuthority(ctx context.Context, id types.CertAuthID, loadSigningKeys bool) (types.CertAuthority, error) {
	return c.ca, nil
}

func TestPostgresPing(t *testing.T) {
	mockClt := setupMockClient(t)

	postgresTestServer, err := postgres.NewTestServer(common.TestServerConfig{
		AuthClient: mockClt,
	})
	require.NoError(t, err)

	go func() {
		t.Logf("Postgres Fake server running at %s port", postgresTestServer.Port())
		require.NoError(t, postgresTestServer.Serve())
	}()
	t.Cleanup(func() {
		postgresTestServer.Close()
	})

	port, err := strconv.Atoi(postgresTestServer.Port())
	require.NoError(t, err)

	p := PostgresPinger{}
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*30)
	defer cancel()
	err = p.Ping(ctx, PingParams{
		Host:         "localhost",
		Port:         port,
		Username:     "someuser",
		DatabaseName: "somedb",
	})

	require.NoError(t, err)
}