package main

import (
	"errors"
	"strings"
)

type name_desc_t struct {
	Name        string
	Description string
}

var err_environ_no_separator = errors.New("No separator found in environ line")

func environ_to_map(environ_strings []string) (result map[string]string, err error) {
	for _, environ_string := range environ_strings {
		key, value, found := strings.Cut(environ_string, "=")
		if !found {
			return result, err_environ_no_separator
		}
		result[key] = value
	}
	return result, err_environ_no_separator
}

package main

import (
	glider_ssh "github.com/gliderlabs/ssh"
	"github.com/go-git/go-billy/v5/osfs"
	"github.com/go-git/go-git/v5/plumbing/protocol/packp"
	"github.com/go-git/go-git/v5/plumbing/transport"
	transport_server "github.com/go-git/go-git/v5/plumbing/transport/server"
)

func ssh_handle_receive_pack(session glider_ssh.Session, repo_identifier string) (err error) {
	repo_path, err := get_repo_path_from_ssh_path(session.Context(), repo_identifier)
	if err != nil {
		return err
	}
	endpoint, err := transport.NewEndpoint("/")
	if err != nil {
		return err
	}
	billy_fs := osfs.New(repo_path)
	fs_loader := transport_server.NewFilesystemLoader(billy_fs)
	transport := transport_server.NewServer(fs_loader)
	receive_pack_session, err := transport.NewReceivePackSession(endpoint, nil)
	if err != nil {
		return err
	}
	advertised_references, err := receive_pack_session.AdvertisedReferencesContext(session.Context())
	if err != nil {
		return err
	}
	err = advertised_references.Encode(session)
	if err != nil {
		return err
	}
	reference_update_request := packp.NewReferenceUpdateRequest()
	err = reference_update_request.Decode(session)
	if err != nil {
		return err
	}
	report_status, err := receive_pack_session.ReceivePack(session.Context(), reference_update_request)
	if err != nil {
		return err
	}
	err = report_status.Encode(session)
	if err != nil {
		return err
	}
	return nil
}

package main

import (
	glider_ssh "github.com/gliderlabs/ssh"
	"github.com/go-git/go-billy/v5/osfs"
	"github.com/go-git/go-git/v5/plumbing/protocol/packp"
	"github.com/go-git/go-git/v5/plumbing/transport"
	"github.com/go-git/go-git/v5/plumbing/transport/server"
)

func ssh_handle_upload_pack(session glider_ssh.Session, repo_identifier string) (err error) {
	repo_path, err := get_repo_path_from_ssh_path(session.Context(), repo_identifier)
	if err != nil {
		return err
	}
	endpoint, err := transport.NewEndpoint("/")
	if err != nil {
		return err
	}
	billy_fs := osfs.New(repo_path)
	fs_loader := server.NewFilesystemLoader(billy_fs)
	transport := server.NewServer(fs_loader)
	upload_pack_session, err := transport.NewUploadPackSession(endpoint, nil)
	if err != nil {
		return err
	}
	advertised_references, err := upload_pack_session.AdvertisedReferencesContext(session.Context())
	if err != nil {
		return err
	}
	err = advertised_references.Encode(session)
	if err != nil {
		return err
	}
	reference_update_request := packp.NewUploadPackRequest()
	err = reference_update_request.Decode(session)
	if err != nil {
		return err
	}
	report_status, err := upload_pack_session.UploadPack(session.Context(), reference_update_request)
	if err != nil {
		return err
	}
	err = report_status.Encode(session)
	if err != nil {
		return err
	}
	return nil
}

package main

import (
	"fmt"
	"net"
	"os"

	"os/exec"

	"strings"

	glider_ssh "github.com/gliderlabs/ssh"
	"go.lindenii.runxiyu.org/lindenii-common/clog"
	go_ssh "golang.org/x/crypto/ssh"
)

var (
	server_public_key_string      string
	server_public_key_fingerprint string
	server_public_key             go_ssh.PublicKey
)

func serve_ssh(listener net.Listener) error {
	host_key_bytes, err := os.ReadFile(config.SSH.Key)
	if err != nil {
		return err
	}

	host_key, err := go_ssh.ParsePrivateKey(host_key_bytes)
	if err != nil {
		return err
	}

	server_public_key = host_key.PublicKey()
	server_public_key_string = string(go_ssh.MarshalAuthorizedKey(server_public_key))
	server_public_key_fingerprint = string(go_ssh.FingerprintSHA256(server_public_key))

	server := &glider_ssh.Server{
		Handler: func(session glider_ssh.Session) {
			client_public_key := session.PublicKey()
			var client_public_key_string string
			if client_public_key != nil {
				client_public_key_string = string(go_ssh.MarshalAuthorizedKey(client_public_key))
			}

			clog.Info("Incoming SSH: " + session.RemoteAddr().String() + " " + strings.TrimSuffix(client_public_key_string, "\n") + " " + session.RawCommand())
			fmt.Fprintln(session.Stderr(), "Lindenii Forge "+VERSION+", source at "+strings.TrimSuffix(config.HTTP.Root, "/")+"/:/source/\r")

			cmd := session.Command()

			if len(cmd) < 2 {
				fmt.Fprintln(session.Stderr(), "Insufficient arguments\r")
				return
			}

			if cmd[0] != "git-upload-pack" {
				fmt.Fprintln(session.Stderr(), "Unsupported command\r")
				return
			}

			fs_path, err := get_repo_path_from_ssh_path(session.Context(), cmd[1])
			if err != nil {
				fmt.Fprintln(session.Stderr(), "Error while getting repo path:", err, "\r")

			switch cmd[0] {
			case "git-upload-pack":
				if len(cmd) > 2 {
					fmt.Fprintln(session.Stderr(), "Too many arguments\r")
					return
				}
				err = ssh_handle_upload_pack(session, cmd[1])
			case "git-receive-pack":
				if len(cmd) > 2 {
					fmt.Fprintln(session.Stderr(), "Too many arguments\r")
					return
				}
				err = ssh_handle_receive_pack(session, cmd[1])
			default:
				fmt.Fprintln(session.Stderr(), "Unsupported command: "+cmd[0]+"\r")

				return
			}

			proc := exec.CommandContext(session.Context(), cmd[0], fs_path)
			proc.Stdin = session
			proc.Stdout = session
			proc.Stderr = session.Stderr()

			err = proc.Start()

			if err != nil {

				fmt.Fprintln(session.Stderr(), "Error while starting process:", err)

				fmt.Fprintln(session.Stderr(), err.Error())

				return

			}
			err = proc.Wait()
			if exit_error, ok := err.(*exec.ExitError); ok {
				fmt.Fprintln(session.Stderr(), "Process exited with error", exit_error.ExitCode())
			} else if err != nil {
				fmt.Fprintln(session.Stderr(), "Error while waiting for process:", err)

			}
		},
		PublicKeyHandler:           func(ctx glider_ssh.Context, key glider_ssh.PublicKey) bool { return true },
		KeyboardInteractiveHandler: func(ctx glider_ssh.Context, challenge go_ssh.KeyboardInteractiveChallenge) bool { return true },
		// It is intentional that we do not check any credentials and accept all connections.
		// This allows all users to connect and clone repositories; when pushing is added later,
		// we will check their public key in the session handler, not in the auth handlers.
	}

	server.AddHostKey(host_key)

	go func() {
		err = server.Serve(listener)
		if err != nil {
			clog.Fatal(1, "Serving SSH: "+err.Error())
		}
	}()

	return nil
}