package gitlab

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"os/exec"
	"regexp"
	"strconv"
	"strings"
	"text/template"
	"time"

	"git.unistack.org/unistack-org/pkgdash/internal/configcli"
	"git.unistack.org/unistack-org/pkgdash/internal/modules"
	"github.com/go-git/go-git/v5"
	gitconfig "github.com/go-git/go-git/v5/config"
	"github.com/go-git/go-git/v5/plumbing"
	"github.com/go-git/go-git/v5/plumbing/object"
	httpauth "github.com/go-git/go-git/v5/plumbing/transport/http"
	"go.unistack.org/micro/v4/logger"
)

var ErrPRNotExist = errors.New("pull request does not exist")

type Gitlab struct {
	URL          string
	Username     string
	Password     string
	PRTitle      string
	PRBody       string
	Repository   string
	RepositoryId string
	Owner        string
	pulls        []*gitlabPull
}

func NewGitlab(cfg configcli.Config) *Gitlab {
	return &Gitlab{
		URL:        cfg.Source.APIURL,
		Username:   cfg.Source.Username,
		Password:   cfg.Source.Password,
		PRTitle:    cfg.PullRequestTitle,
		PRBody:     cfg.PullRequestBody,
		Repository: cfg.Source.Repository,
		Owner:      cfg.Source.Owner,
	}
}

type gitlabPull struct {
	URL    string `json:"web_url"`
	Title  string `json:"title"`
	Target string `json:"target_branch"`
	Source string `json:"source_branch"`
	ID     int64  `json:"id"`
}

type gitlabProject struct {
	Id   int64  `json:"id"`
	Name string `json:"name"`
}

func (g *Gitlab) Name() string {
	return "gitlab"
}

func (g *Gitlab) RequestOpen(ctx context.Context, branch string, path string, mod modules.Update) error {
	logger.Debug(ctx, fmt.Sprintf("RequestOpen start, mod title: %s", path))

	var buf []byte
	var err error
	// создания шаблона названия для пулл реквеста
	tplTitle, err := template.New("pull_request_title").Parse(g.PRTitle)
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to parse template: %v", err))
	}

	wTitle := bytes.NewBuffer(nil)
	// создания шаблона тела для пулл реквеста
	tplBody, err := template.New("pull_request_body").Parse(g.PRTitle)
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to parse template: %v", err))
	}

	wBody := bytes.NewBuffer(nil)

	data := map[string]string{
		"Name":       path,
		"VersionOld": mod.Module.Version,
		"VersionNew": mod.Version,
	}

	if err = tplTitle.Execute(wTitle, data); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to execute template: %v", err))
	}
	if err = tplBody.Execute(wBody, data); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to execute template: %v", err))
	}

	// открытие гит репозитория с опцией обхода репозитория для нахождения .git
	repo, err := git.PlainOpenWithOptions(".", &git.PlainOpenOptions{DetectDotGit: true})
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to open repo: %v", err))
	}
	//извлекаем ссылки с объектами из удаленного объекта??
	if err = repo.FetchContext(ctx, &git.FetchOptions{
		//	Auth:  &httpauth.BasicAuth{Username: g.Username, Password: g.Password},
		Force: true,
	}); err != nil && err != git.NoErrAlreadyUpToDate {
		logger.Fatal(ctx, fmt.Sprintf("failed to fetch repo : %v", err))
	} //обновляем репозиторий

	var headRef *plumbing.Reference // вроде ссылка на гит

	refIter, err := repo.Branches() //получение веток
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to get branches: %v", err))
		return err
	}
	for {
		ref, err := refIter.Next()
		if err != nil {
			break
		}
		if ref.Name().Short() == branch { //todo вот тут возможно нужно переделать
			headRef = ref
			break
		}
	} //перебираем получение ветки и когда находим нужную выходим из цикла записав ветку в headRef
	refIter.Close()

	if headRef == nil {
		logger.Fatal(ctx, "failed to get repo branch head")
		return err
	} // Не получили нужную ветку

	logger.Info(ctx, fmt.Sprintf("repo head %s", headRef))

	wtree, err := repo.Worktree() //todo вроде рабочее дерево не нужно
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to get worktree: %v", err))
	}
	defer checkout(wtree, *headRef)

	g.RepositoryId, err = GetRepoID(ctx, g.URL, g.Owner, g.Repository, g.Password)
	if err != nil || g.RepositoryId == "" {
		return fmt.Errorf("project id is empty")
	}

	g.pulls, err = GetPulls(ctx, g.URL, g.RepositoryId, branch, g.Password)
	if err != nil && err != ErrPRNotExist {
		logger.Error(ctx, fmt.Sprintf("GetPulls error: %s", err))
		return err
	}

	for _, pull := range g.pulls {
		if strings.Contains(pull.Title, path) {
			logger.Info(ctx, fmt.Sprintf("PR for %s exists %s, call RequestUpdate", path, pull.URL))
			return g.RequestUpdate(ctx, branch, path, mod)
		} // хотим проверить есть ли пулл реквест для этой ветки, если есть то выходим
	}

	logger.Info(ctx, fmt.Sprintf("update %s from %s to %s", path, mod.Module.Version, mod.Version))

	sourceBranch := fmt.Sprintf("pkgdash/go_modules/%s-%s", path, mod.Version)

	logger.Info(ctx, "reset worktree")
	if err = wtree.Reset(&git.ResetOptions{Commit: headRef.Hash(), Mode: git.HardReset}); err != nil {
		logger.Error(ctx, fmt.Sprintf("failed to reset repo branch: %v", err))
	}

	if err = wtree.PullContext(ctx, &git.PullOptions{
		Auth:  &httpauth.BasicAuth{Username: g.Username, Password: g.Password},
		Depth: 1,
		//	RemoteURL :
		Force:      true,
		RemoteName: "origin",
	}); err != nil && err != git.NoErrAlreadyUpToDate {
		logger.Error(ctx, fmt.Sprintf("failed to pull repo: %v", err)) //подтягиваем изменения с удаленого репозитория
	}

	logger.Info(ctx, fmt.Sprintf("checkout ref %s", headRef))
	if err = wtree.Checkout(&git.CheckoutOptions{
		Hash:   headRef.Hash(),
		Branch: plumbing.NewBranchReferenceName(sourceBranch),
		Create: true,
		Force:  true,
	}); err != nil {
		logger.Error(ctx, fmt.Sprintf("failed to checkout tree: %v", err))
		return err
	} //создаем новую ветку

	epath, err := exec.LookPath("go")
	if errors.Is(err, exec.ErrDot) {
		err = nil
	}
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to find go command: %v", err))
	} // ищем go файл

	var cmd *exec.Cmd
	var out []byte

	cmd = exec.CommandContext(ctx, epath, "mod", "edit", fmt.Sprintf("-droprequire=%s", mod.Module.Path))
	if out, err = cmd.CombinedOutput(); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to run go mod edit: %s err: %v", out, err))
	}

	cmd = exec.CommandContext(ctx, epath, "mod", "edit", fmt.Sprintf("-require=%s@%s", path, mod.Version))
	if out, err = cmd.CombinedOutput(); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to run go mod edit: %s err: %v", out, err))
	} // пытаемся выполнить команду go mod edit с новой версией модуля

	cmd = exec.CommandContext(ctx, epath, "mod", "tidy")
	if out, err = cmd.CombinedOutput(); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to run go mod tidy: %s err: %v", out, err))
	} // пытаемся выполнить команду go mod tidy пытаемся подтянуть новую версию модуля

	logger.Info(ctx, "worktree add go.mod")
	if _, err = wtree.Add("go.mod"); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to add file: %v", err))
	}

	logger.Info(ctx, "worktree add go.sum")
	if _, err = wtree.Add("go.sum"); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to add file: %v", err))
	}

	logger.Info(ctx, "worktree commit")
	_, err = wtree.Commit(wTitle.String(), &git.CommitOptions{
		Parents: []plumbing.Hash{headRef.Hash()},
		Author: &object.Signature{
			Name:  "gitea-actions",
			Email: "info@unistack.org",
			When:  time.Now(),
		},
	}) // хотим за коммитить изменения
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to commit: %v", err))
	}

	refspec := gitconfig.RefSpec(fmt.Sprintf("+refs/heads/pkgdash/go_modules/%s-%s:refs/heads/pkgdash/go_modules/%s-%s", path, mod.Version, path, mod.Version)) //todo как будто нужно переделать

	logger.Info(ctx, fmt.Sprintf("try to push refspec %s", refspec))

	if err = repo.PushContext(ctx, &git.PushOptions{
		RefSpecs: []gitconfig.RefSpec{refspec},
		Auth:     &httpauth.BasicAuth{Username: g.Username, Password: g.Password},
		Force:    true,
	}); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to push repo branch: %v", err))
	} // пытаемся за пушить изменения

	body := map[string]string{
		"id":            g.RepositoryId,
		"source_branch": sourceBranch,
		"target_branch": branch,
		"title":         wTitle.String(),
		"description":   wBody.String(),
	}
	logger.Info(ctx, fmt.Sprintf("raw body: %#+v", body))

	buf, err = json.Marshal(body)
	if err != nil {
		return err
	}

	logger.Info(ctx, fmt.Sprintf("marshal body: %s", buf))

	req, err := http.NewRequestWithContext(
		ctx,
		http.MethodPost,
		fmt.Sprintf("https://%s/api/v4/projects/%s/merge_requests", g.URL, g.RepositoryId),
		bytes.NewReader(buf),
	)
	if err != nil {
		return err
	}
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("Authorization", g.Password)

	rsp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	} //Вроде создаем новый реквест на создание пулл реквеста
	if rsp.StatusCode != http.StatusCreated {
		buf, _ = io.ReadAll(rsp.Body)
		return fmt.Errorf("unknown error: %s", buf)
	}

	logger.Info(ctx, fmt.Sprintf("PR create for %s-%s", path, mod.Version))

	return nil
}

func (g *Gitlab) RequestClose(ctx context.Context, branch string, path string) error {
	logger.Debug(ctx, fmt.Sprintf("RequestClose start, mod title: %s", path))

	var err error

	g.RepositoryId, err = GetRepoID(ctx, g.URL, g.Owner, g.Repository, g.Password)
	if err != nil || g.RepositoryId == "" {
		return fmt.Errorf("project id is empty")
	}

	pulls, err := GetPulls(ctx, g.URL, g.RepositoryId, branch, g.Password)
	if err != nil {
		logger.Error(ctx, fmt.Sprintf("GetPulls error: %s", err))
		return err
	}

	prExist := false
	var b string // Name of the branch to be deleted
	for _, pull := range pulls {
		if strings.Contains(pull.Title, path) {
			logger.Info(ctx, fmt.Sprintf("PR for %s exists: %s", path, pull.URL))
			prExist = true
			b = pull.Source
		}
	}
	if !prExist {
		logger.Error(ctx, fmt.Sprintf("skip %s since pr does not exist", path))
		return ErrPRNotExist
	}

	req, err := DeleteBranch(ctx, g.URL, g.RepositoryId, b, g.Password)
	if err != nil {
		logger.Error(ctx, fmt.Sprintf("failed to create request for delete the branch: %s, err: %s", branch, err))
		return err
	}
	rsp, err := http.DefaultClient.Do(req)
	if err != nil {
		logger.Error(ctx, fmt.Sprintf("failed to do request for delete the branch: %s, err: %s, code: %v", branch, err, rsp.StatusCode))
		return err
	}

	logger.Info(ctx, fmt.Sprintf("Delete branch for %s successful", path))
	return nil
}

func (g *Gitlab) RequestUpdate(ctx context.Context, branch string, path string, mod modules.Update) error {
	logger.Debug(ctx, fmt.Sprintf("RequestUpdate start, mod title: %s", path))
	var err error

	g.RepositoryId, err = GetRepoID(ctx, g.URL, g.Owner, g.Repository, g.Password)
	if err != nil || g.RepositoryId == "" {
		return fmt.Errorf("project id is empty")
	}

	if len(g.pulls) == 0 {
		g.pulls, err = GetPulls(ctx, g.URL, g.RepositoryId, branch, g.Password)
		if err != nil {
			logger.Error(ctx, fmt.Sprintf("GetPulls error: %s", err))
			return err
		}
	}

	prExist := false
	for _, pull := range g.pulls {
		if strings.Contains(pull.Title, path) {
			logger.Info(ctx, fmt.Sprintf("don't skip %s since pr exist %s", path, pull.URL)) //todo
			tVersion := getVersions(pull.Source)                                             //Надо взять просто из названия ветки последнюю версию
			if modules.IsNewerVersion(tVersion, mod.Version, false) {
				reqDel, err := DeleteBranch(ctx, g.URL, g.RepositoryId, pull.Source, g.Password)
				if err != nil {
					logger.Error(ctx, fmt.Sprintf("Error with create request for branch: %s, err: %s", branch, err))
					return err
				}
				rsp, err := http.DefaultClient.Do(reqDel)
				if err != nil {
					logger.Error(ctx, fmt.Sprintf("Error with do request for branch: %s, err: %s, code: %v", branch, err, rsp.StatusCode))
					return err
				}
				logger.Info(ctx, fmt.Sprintf("Old pr %s successful delete", pull.Source))
			} else {
				logger.Debug(ctx, "The existing PR is relevant")
				return nil
			}
			prExist = true
		}
	}
	if !prExist {
		logger.Error(ctx, fmt.Sprintf("skip %s since pr does not exist", path))
		return ErrPRNotExist
	}

	return g.RequestOpen(ctx, branch, path, mod) // todo это мне не нравится
}

func (g *Gitlab) RequestList(ctx context.Context, branch string) (map[string]string, error) {
	logger.Debug(ctx, fmt.Sprintf("RequestList for %s", branch))
	var err error

	g.RepositoryId, err = GetRepoID(ctx, g.URL, g.Owner, g.Repository, g.Password)
	if err != nil || g.RepositoryId == "" {
		return nil, fmt.Errorf("project id is empty")
	}

	g.pulls, err = GetPulls(ctx, g.URL, g.RepositoryId, branch, g.Password)
	if err != nil {
		return nil, err
	}

	var path string
	rMap := make(map[string]string)

	for _, pull := range g.pulls {
		if !strings.HasPrefix(pull.Title, "Bump ") { //добавляем только реквесты бота по обновлению модулей
			continue
		}
		path = strings.Split(pull.Title, " ")[1] //todo Работет только для дефолтного шаблона
		rMap[path] = pull.Title
	}
	return rMap, nil
}

func getVersions(s string) string {
	re := regexp.MustCompile("[vV][0-9]+\\.[0-9]+\\.[0-9]+")

	version := re.FindString(s)

	return version
}

func DeleteBranch(ctx context.Context, url, projectId, branch, password string) (*http.Request, error) {
	var buf []byte
	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, fmt.Sprintf("https://%s/api/v4/projects/%s/repository/branches/%s", url, projectId, branch), bytes.NewReader(buf))
	if err != nil {
		return nil, err
	}
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("Authorization", password)
	return req, err
}

func GetPulls(ctx context.Context, url, projectId, branch, password string) ([]*gitlabPull, error) {
	pulls := make([]*gitlabPull, 0, 10)
	req, err := http.NewRequestWithContext(
		ctx,
		http.MethodGet,
		fmt.Sprintf("https://%s/api/v4/projects/%s/merge_requests?state=opened&target_branch=%s", url, projectId, branch),
		nil)
	if err != nil {
		return nil, err
	} //вроде запроса к репозиторию

	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("Authorization", password)

	rsp, err := http.DefaultClient.Do(req) // выполнение запроса
	if err != nil {
		return nil, err
	}

	buf, _ := io.ReadAll(rsp.Body)

	switch rsp.StatusCode {
	case http.StatusOK:
		if err = json.Unmarshal(buf, &pulls); err != nil {
			logger.Error(ctx, fmt.Sprintf("failed to decode response %s err: %v", buf, err))
			return nil, err
		}
		return pulls, nil
	case http.StatusNotFound:
		logger.Info(ctx, fmt.Sprintf("pull-request is not exist for %s", projectId))
		return nil, ErrPRNotExist
	default:
		return nil, fmt.Errorf("unknown error: %s", buf)
	}
}

func GetRepoID(ctx context.Context, url, owner, repo, password string) (rId string, err error) {
	var buf []byte
	projects := make([]*gitlabProject, 0, 10)
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, fmt.Sprintf("https://%s/api/v4/users/%s/projects?owned=true", url, owner), nil)
	if err != nil {
		return
	}
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("Authorization", password)

	rsp, err := http.DefaultClient.Do(req)
	if err != nil {
		return
	}

	buf, _ = io.ReadAll(rsp.Body)

	switch rsp.StatusCode {
	case http.StatusOK:
		if err = json.Unmarshal(buf, &projects); err != nil {
			logger.Error(ctx, fmt.Sprintf("failed to decode response %s err: %v", buf, err))
		}
		for _, p := range projects {
			if p.Name == repo {
				rId = strconv.Itoa(int(p.Id))
			}
		}
		return
	default:
		return rId, fmt.Errorf("unknown error: %s", buf)
	}
}

func checkout(w *git.Worktree, ref plumbing.Reference) {
	ctx := context.Background()
	if err := w.Reset(&git.ResetOptions{Commit: ref.Hash(), Mode: git.HardReset}); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to reset: %v", err))
	}
}