package git

import (
	"errors"
	"farga/lib"
	errs "farga/lib/errors"
	"time"

	"github.com/go-git/go-git/v6"
	"github.com/go-git/go-git/v6/plumbing/object"
)

type LogOptions struct {
	Repo     *git.Repository
	Branch   string
	FileName string
}

type GitCommitAuthor struct {
	Name  string
	Email string
}

type Commit struct {
	Hash      string
	ShortHash string
	Author    GitCommitAuthor
	Message   string
	Time      time.Time
}

type Log []Commit

// gets the log of a branch or file. Don't forget to pass in your repo!
func GetLog(o LogOptions) (Log, error) {
	if o.Repo == nil {
		return nil, errs.ErrMissingProperty("Repo")
	}

	ref, err := ResolveHead(o.Repo, o.Branch)

	if err != nil {
		return nil, err
	}

	if ref == nil {
		return nil, ErrRepoHasNoHead
	}

	gitLog, err := o.Repo.Log(&git.LogOptions{
		From: ref.Hash(),
	})

	if err != nil {
		return nil, err
	}

	var log Log

	err = gitLog.ForEach(func(c *object.Commit) error {
		shortHash, err := ShortenHash(c.Hash.String())
		if err != nil {
			return errors.New("Invalid hash length")
		}
		log = append(log, Commit{
			Hash:      c.Hash.String(),
			ShortHash: shortHash,
			Author: GitCommitAuthor{
				Name:  c.Author.Name,
				Email: c.Author.Email,
			},
			Message: c.Message,
			Time:    c.Author.When,
		})
		return nil
	})

	return log, err
}

// shortens a hash. returns the full string if it's asked to trim it at a length greater than it is.
func ShortenHash(hash string) (string, error) {
	return lib.TruncateString(hash, lib.GitHashLength)
}