package git

import (
	"errors"
	"fmt"
	"io"

	"github.com/go-git/go-git/v5"
	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/object"
)

var ()

var (
	MissingHeadErr = errors.New("Head not found")
)

type (
	GitRepository struct {
		path string
	}
)

func NewGitRepository(dir string) *GitRepository {
	return &GitRepository{
		path: dir,
	}
}

func (g *GitRepository) Path() string {
	return g.path
}

func (g *GitRepository) LastCommit() (*object.Commit, error) {
	repo, err := git.PlainOpen(g.path)
	if err != nil {
		return nil, err
	}

	ref, err := repo.Head()
	if err != nil {
		return nil, errors.Join(MissingHeadErr, err)
	}

	c, err := repo.CommitObject(ref.Hash())
	if err != nil {
		return nil, err
	}
	return c, nil
}

func (g *GitRepository) Commits() ([]*object.Commit, error) {
	repo, err := git.PlainOpen(g.path)
	if err != nil {
		return nil, err
	}

	ref, err := repo.Head()
	if err != nil {
		return nil, errors.Join(MissingHeadErr, err)
	}

	ci, err := repo.Log(&git.LogOptions{From: ref.Hash()})
	if err != nil {
		return nil, fmt.Errorf("commits from ref: %w", err)
	}

	commits := []*object.Commit{}
	// TODO: for now only load first 1000
	for x := 0; x < 1000; x++ {
		c, err := ci.Next()
		if err != nil && errors.Is(err, io.EOF) {
			break
		} else if err != nil {
			return nil, err
		}
		commits = append(commits, c)
	}
	if err != nil {
		return nil, err
	}

	return commits, nil
}

func (g *GitRepository) Tags() ([]*object.Tag, error) {
	repo, err := git.PlainOpen(g.path)
	if err != nil {
		return nil, err
	}

	ti, err := repo.TagObjects()
	if err != nil {
		return nil, err
	}

	tags := []*object.Tag{}
	err = ti.ForEach(func(t *object.Tag) error {
		tags = append(tags, t)
		return nil
	})
	if err != nil {
		return nil, err
	}

	return tags, nil
}

func (g *GitRepository) Branches() ([]*plumbing.Reference, error) {
	repo, err := git.PlainOpen(g.path)
	if err != nil {
		return nil, err
	}

	bs, err := repo.Branches()
	if err != nil {
		return nil, err
	}

	branches := []*plumbing.Reference{}
	err = bs.ForEach(func(ref *plumbing.Reference) error {
		branches = append(branches, ref)
		return nil
	})
	if err != nil {
		return nil, err
	}

	return branches, nil
}