package roast

import (
	"context"
	"errors"
	"fmt"
	"git-roast/internal/config"
	"git-roast/internal/log"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

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

type Roast struct {
	repo *git.Repository
	dir  string
}

func getRepoOrigin() (string, error) {
	repo, err := git.PlainOpen(".")
	if err != nil {
		return "", errors.Join(errors.New("failed to open repository"), err)
	}

	origin, err := repo.Remote("origin")
	if err != nil {
		return "", errors.Join(errors.New("failed to open remote origin"), err)
	}

	originConfig := origin.Config()
	if originConfig == nil {
		return "", errors.New("failed to read origin config")
	}

	if len(originConfig.URLs) == 0 {
		return "", errors.New("no urls in remote origin")
	}

	return originConfig.URLs[0], nil
}

func Init() error {
	repoOriginUrl, err := getRepoOrigin()
	if err != nil {
		return err
	}
	id := url.PathEscape(repoOriginUrl)

	p := filepath.Join(config.ContentPath, id)

	initSuccessful := false
	defer func() {
		if !initSuccessful {
			_ = os.RemoveAll(p)
		}
	}()

	if err := os.RemoveAll(p); err != nil && !os.IsNotExist(err) {
		return err
	}

	var roastRepoOriginUrl string
	if s, hasSuffix := strings.CutSuffix(repoOriginUrl, ".git"); hasSuffix {
		roastRepoOriginUrl = s + ".roast.git"
	} else {
		roastRepoOriginUrl = s + ".roast"
	}

	{
		ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
		defer cancel()
		cmd := exec.CommandContext(
			ctx,
			"git",
			"clone",
			roastRepoOriginUrl,
			p,
		)
		if out, err := cmd.CombinedOutput(); err != nil {
			log.Printf("failed to clone %s\n%s\n%s\n", roastRepoOriginUrl, out, err.Error())
		} else {
			log.Debugf("cloned %s\n", roastRepoOriginUrl)

			repo, err := git.PlainOpen(p)
			if err != nil {
				return errors.Join(errors.New("failed to open roast repo"), err)
			}
			if commitIter, err := repo.CommitObjects(); err != nil {
				return errors.Join(errors.New("failed to get commits for roast repo"), err)
			} else if _, err := commitIter.Next(); err != nil {
				// repo has no commits
				// git commit --allow-empty -m init
				cmd = exec.Command("git", "commit", "--allow-empty", "-m", "init")
				cmd.Dir = p
				if out, err := cmd.CombinedOutput(); err != nil {
					return errors.Join(fmt.Errorf("failed to add initial commit to roast repo\n%s\n", out), err)
				}
				// git push -u origin main
				cmd = exec.Command("git", "push", "-u", "origin", "main")
				cmd.Dir = p
				if out, err := cmd.CombinedOutput(); err != nil {
					return errors.Join(fmt.Errorf("failed to push roast repo to %s\n%s\n", roastRepoOriginUrl, out), err)
				}
				log.Debugf("roast repository init pushed to %s\n", roastRepoOriginUrl)
			}

			initSuccessful = true
			return nil
		}
	}

	{
		// git init
		cmd := exec.Command("git", "init", p)
		if out, err := cmd.CombinedOutput(); err != nil {
			return errors.Join(fmt.Errorf("failed to init %s\n%s\n", roastRepoOriginUrl, out), err)
		}
		log.Debugf("init %s successful\n", roastRepoOriginUrl)
		// git remote add origin $roastRepoOriginUrl
		cmd = exec.Command("git", "remote", "add", "origin", roastRepoOriginUrl)
		cmd.Dir = p
		if out, err := cmd.CombinedOutput(); err != nil {
			return errors.Join(fmt.Errorf("failed to add remote %s to roast repo\n%s\n", roastRepoOriginUrl, out), err)
		}
		// git commit --allow-empty -m init
		cmd = exec.Command("git", "commit", "--allow-empty", "-m", "init")
		cmd.Dir = p
		if out, err := cmd.CombinedOutput(); err != nil {
			return errors.Join(fmt.Errorf("failed to add initial commit to roast repo\n%s\n", out), err)
		}
		// git push -u origin main
		cmd = exec.Command("git", "push", "-u", "origin", "main")
		cmd.Dir = p
		if out, err := cmd.CombinedOutput(); err != nil {
			return errors.Join(fmt.Errorf("failed to push roast repo to %s\n%s\n", roastRepoOriginUrl, out), err)
		}
		log.Debugf("new roast repository pushed to %s\n", roastRepoOriginUrl)
	}

	initSuccessful = true
	return nil
}

func Open() (*Roast, error) {
	repoOriginUrl, err := getRepoOrigin()
	if err != nil {
		return nil, err
	}
	id := url.PathEscape(repoOriginUrl)

	p := filepath.Join(config.ContentPath, id)
	if stat, err := os.Stat(p); err != nil {
		if os.IsNotExist(err) {
			return nil, errors.New("roast repo not initialized, use `git roast init`")
		} else {
			return nil, errors.Join(errors.New("failed to check if roast dir for repo exists"), err)
		}
	} else if !stat.IsDir() {
		return nil, errors.Join(errors.New("path for roast dir for repo exists but is not a directory"), err)
	}

	roastRepo, err := git.PlainOpen(p)
	if err != nil {
		return nil, errors.Join(fmt.Errorf("failed to open roast repo %s", p), err)
	}

	pull := exec.Command("git", "pull", "--force")
	pull.Dir = p
	if err := pull.Run(); err != nil {
		return nil, errors.Join(fmt.Errorf("failed to pull roast repo %s", p), err)
	}

	return &Roast{
		repo: roastRepo,
		dir:  p,
	}, nil
}