package main

import (
	"io/ioutil"
	"os"
	"path"
	"testing"
	"time"

	"github.com/pkg/errors"

	git "github.com/libgit2/git2go/v30"
)

func checkFatal(t *testing.T, err error) {
	if err != nil {
		t.Fatalf("%+v", err)
	}
}

func cleanupRepo(t *testing.T, repo *git.Repository) {
	err := os.RemoveAll(repo.Workdir())
	if err != nil {
		t.Errorf("failed cleaning up repo")
	}
}

func newTestRepo(t *testing.T) *git.Repository {
	dir, err := ioutil.TempDir("", "test-repo-")
	checkFatal(t, errors.Wrap(err, "Failed creating test repo directory"))

	repo, err := git.InitRepository(dir, false)
	checkFatal(t, errors.Wrap(err, "Failed initializing a temp repo"))

	// Automatically remove repo when test is over
	t.Cleanup(func() {
		cleanupRepo(t, repo)
	})
	return repo
}

func createFile(t *testing.T, repo *git.Repository, name string) {
	err := ioutil.WriteFile(path.Join(repo.Workdir(), name), []byte("I'm a file"), 0644)
	checkFatal(t, errors.Wrap(err, "Failed writing a file"))
}

func stageFile(t *testing.T, repo *git.Repository, name string) {
	index, err := repo.Index()
	checkFatal(t, errors.Wrap(err, "Failed getting repo index"))

	err = index.AddByPath(name)
	checkFatal(t, errors.Wrap(err, "Failed adding file to index"))

	err = index.Write()
	checkFatal(t, errors.Wrap(err, "Failed writing index"))
}

func createCommit(t *testing.T, repo *git.Repository, message string) *git.Commit {
	index, err := repo.Index()
	checkFatal(t, errors.Wrap(err, "Failed getting repo index"))

	treeId, err := index.WriteTree()
	checkFatal(t, errors.Wrap(err, "Failed building tree from index"))

	tree, err := repo.LookupTree(treeId)
	checkFatal(t, errors.Wrap(err, "Failed looking up tree id"))

	signature := &git.Signature{
		Name:  "Some Guy",
		Email: "someguy@example.com",
		When:  time.Date(2000, 01, 01, 16, 00, 00, 0, time.UTC),
	}

	empty, err := repo.IsEmpty()
	checkFatal(t, errors.Wrap(err, "Failed checking if repo is empty"))

	var commitId *git.Oid
	if !empty {
		currentBranch, err := repo.Head()
		checkFatal(t, errors.Wrap(err, "Failed getting current branch"))

		currentTip, err := repo.LookupCommit(currentBranch.Target())
		checkFatal(t, errors.Wrap(err, "Failed getting current tip"))

		commitId, err = repo.CreateCommit("HEAD", signature, signature, message, tree, currentTip)
	} else {
		commitId, err = repo.CreateCommit("HEAD", signature, signature, message, tree)
	}

	commit, err := repo.LookupCommit(commitId)
	checkFatal(t, errors.Wrap(err, "Failed looking up a commit"))

	return commit
}

func createBranch(t *testing.T, repo *git.Repository, name string) *git.Branch {
	head, err := repo.Head()
	checkFatal(t, errors.Wrap(err, "Failed getting repo head"))

	commit, err := repo.LookupCommit(head.Target())
	checkFatal(t, errors.Wrap(err, "Failed getting commit id from head"))

	branch, err := repo.CreateBranch(name, commit, false)
	checkFatal(t, errors.Wrap(err, "Failed creating branch"))

	return branch
}