// SPDX-FileCopyrightText: 2025 Romain Maneschi <romain@gitroot.dev>
//
// SPDX-License-Identifier: EUPL-1.2

package repository

import (
	"context"
	"fmt"
	"os"
	"testing"

	git "github.com/go-git/go-git/v6"
	"github.com/go-git/go-git/v6/plumbing"
	"github.com/go-git/go-git/v6/plumbing/object"
	"gitroot.dev/server/configuration"
	"gitroot.dev/server/user"
)

// | - commit5
// | | - commit4 -- branch2
// | | commit3
// | - commit2 -- branch1
// - commit1
// - init -- main
func TestFoundAncestor(t *testing.T) {
	dataDir := t.TempDir()
	conf := configuration.NewConfiguration(dataDir)
	userManager, _ := user.NewManager(conf)
	m := NewManager(conf, userManager)
	repoConf := RepoConf{Name: "foundAncestor", DefaultBranch: "main"}
	err := m.CreateUserRepo(context.TODO(), repoConf, []user.SimpleUser{}, []byte(""))
	if err != nil {
		t.Fatal(err)
	}
	repo, err := m.Open(context.TODO(), "foundAncestor")
	if err != nil {
		t.Fatal(err)
	}
	repoWriter, err := repo.WillWrite(plumbing.HEAD)
	if err != nil {
		t.Fatal(err)
	}
	h1 := makeCommit(repoWriter, 1, t, userManager)
	if err := repoWriter.Branch("branch1", h1); err != nil {
		t.Fatal(err)
	}
	h2 := makeCommit(repoWriter, 2, t, userManager)

	h3 := makeCommit(repoWriter, 3, t, userManager)
	if err := repoWriter.Branch("branch2", h3); err != nil {
		t.Fatal(err)
	}
	makeCommit(repoWriter, 4, t, userManager)
	if err := repoWriter.worktree.Checkout(&git.CheckoutOptions{Branch: plumbing.NewBranchReferenceName("branch1"), Force: true}); err != nil {
		t.Fatal(err)
	}
	h5 := makeCommit(repoWriter, 5, t, userManager)

	commits := []*object.Commit{}
	os.Stdout.WriteString("------\n")
	repo.hasBecomeWrite.WalkCommit(h1, h5, func(c *object.Commit) error {
		os.Stdout.WriteString(fmt.Sprintf("%s=%s\n", c.Hash.String(), c.Message))
		commits = append(commits, c)
		return nil
	})
	os.Stdout.WriteString("------\n")

	res := []plumbing.Hash{h5, h3, h2, h1}

	if len(commits) != len(res) {
		t.Fatalf("commits should be %d but was %d", len(res), len(commits))
	}
	for i, r := range res {
		if !commits[i].Hash.Equal(r) {
			t.Fatalf("commit %d should be %s but was %s", i, r.String(), commits[0].Hash.String())
		}
	}

	repo.Close()
}

func makeCommit(repo *GitRootRepositoryWrite, nb int, t *testing.T, u *user.Manager) plumbing.Hash {
	if err := repo.Write("README.md", []byte(fmt.Sprintf("commit%d", nb))); err != nil {
		t.Fatal(err)
	}
	h, err := repo.CommitAll(fmt.Sprintf("commit%d", nb), u.RootCommiter())
	if err != nil {
		t.Fatal(err)
	}
	return h
}