package main

import (
	"errors"

	"fmt"
	"os/exec"

	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"

)

var err_unauthorized_push = errors.New("You are not authorized to push to this repository")

func ssh_handle_receive_pack(session glider_ssh.Session, pubkey string, repo_identifier string) (err error) {
	repo_path, access, err := get_repo_path_perms_from_ssh_path_pubkey(session.Context(), repo_identifier, pubkey)
	if err != nil {
		return err
	}
	if !access {
		return err_unauthorized_push
	}

	endpoint, err := transport.NewEndpoint("/")

	proc := exec.CommandContext(session.Context(), "git-receive-pack", repo_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)

		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

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

	return err

}