package gitea

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

	"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/v3/logger"
	"go.unistack.org/pkgdash/internal/configcli"
	"go.unistack.org/pkgdash/internal/modules"
	gogit "go.unistack.org/pkgdash/internal/source/git"
)

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

type Gitea struct {
	logger     logger.Logger
	URL        string
	Username   string
	Password   string
	PRTitle    string
	PRBody     string
	Repository string
	Owner      string
	pulls      []*giteaPull
}

func NewGitea(cfg configcli.Config, log logger.Logger) *Gitea {
	return &Gitea{
		logger:     log,
		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 giteaPull struct {
	URL   string `json:"url"`
	Title string `json:"title"`
	Base  struct {
		Ref string `json:"ref"`
	} `json:"base"`
	Head struct {
		Ref string `json:"ref"`
	} `json:"head"`
	ID int64 `json:"id"`
}

func (g *Gitea) Name() string {
	return "gitea"
}

func (g *Gitea) RequestOpen(ctx context.Context, branch string, path string, mod modules.Update) error {
	g.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 {
		g.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 {
		g.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 {
		g.logger.Error(ctx, "failed to execute template", err)
		return err
	}
	if err = tplBody.Execute(wBody, data); err != nil {
		g.logger.Error(ctx, "failed to execute template", err)
		return err
	}

	// открытие гит репозитория с опцией обхода репозитория для нахождения .git
	repo, err := gogit.PlainOpenWithOptions(".", &git.PlainOpenOptions{DetectDotGit: true})
	if err != nil {
		g.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 {
		g.logger.Error(ctx, "failed to fetch repo", err)
		return err
	} // обновляем репозиторий

	var headRef *plumbing.Reference

	branches, err := repo.Branches()
	if err != nil {
		g.logger.Error(ctx, "cant get repo branches", err)
		return err
	}

	for _, ref := range branches {
		if ref.Name().Short() == branch {

			headRef = plumbing.NewHashReference(ref.Name(), ref.Hash())
			g.logger.Info(ctx, "headRef set to "+headRef.String())
			break
		}
	}

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

	g.logger.Info(ctx, "repo head "+headRef.String())

	wtree, err := repo.Worktree() // todo вроде рабочее дерево не нужно
	if err != nil {
		g.logger.Error(ctx, "failed to get worktree", err)
		return err
	}

	g.pulls, err = g.GetPulls(ctx, g.URL, g.Owner, g.Repository, g.Password)
	if err != nil && err != ErrPRNotExist {
		g.logger.Error(ctx, "GetPulls error", err)
		return err
	}

	for _, pull := range g.pulls {
		if strings.Contains(pull.Title, path) && strings.Contains(pull.Base.Ref, branch) {
			g.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
	}

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

	wstatus, err := wtree.Status()
	if err != nil {
		g.logger.Error(ctx, "failed to get worktree status", err)
		return err
	}

	g.logger.Info(ctx, "worktree status "+wstatus.String())
	/*
		g.logger.Info(ctx, "try to reset worktree to "+headRef.Hash().String())
		if err = wtree.Reset(&git.ResetOptions{Commit: headRef.Hash(), Mode: git.HardReset}); err != nil {
			g.logger.Error(ctx, "failed to reset repo branch to "+headRef.Hash().String(), err)
			return err
		} // вроде меняем ветку todo вроде можно удалить
	*/
	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 {
		g.logger.Error(ctx, fmt.Sprintf("failed to pull repo: %v", err)) // подтягиваем изменения с удаленого репозитория
		return err
	}

	g.logger.Info(ctx, fmt.Sprintf("checkout ref %s", headRef))

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

	defer func() {
		_ = g.checkout(wtree, headRef)
	}()

	epath, err := exec.LookPath("go")
	if errors.Is(err, exec.ErrDot) {
		err = nil
	}
	if err != nil {
		g.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 {
		g.logger.Error(ctx, fmt.Sprintf("failed to run go mod edit: %s err: %v", out, err))
		return err
	}

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

	g.logger.Info(ctx, "worktree add go.mod")
	if err = wtree.AddWithOptions(&git.AddOptions{Path: "go.mod"}); err != nil {
		g.logger.Error(ctx, fmt.Sprintf("failed to add file: %v", err))
		return err
	}

	g.logger.Info(ctx, "worktree add go.sum")
	if err = wtree.AddWithOptions(&git.AddOptions{Path: "go.sum"}); err != nil {
		g.logger.Error(ctx, fmt.Sprintf("failed to add file: %v", err))
		return err
	}

	g.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 {
		g.logger.Error(ctx, fmt.Sprintf("failed to commit: %v", err))
		return 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

	g.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 {
		g.logger.Error(ctx, "failed to push repo branch", err)
		return err
	} // пытаемся за пушить изменения

	body := map[string]string{
		"base":  branch,
		"body":  wBody.String(),
		"head":  fmt.Sprintf("pkgdash/go_modules/%s-%s", path, mod.Version),
		"title": wTitle.String(),
	}
	g.logger.Info(ctx, fmt.Sprintf("raw body: %#+v", body))

	buf, err = json.Marshal(body)
	if err != nil {
		g.logger.Error(ctx, "failed to marshal", err)
		return err
	}

	g.logger.Info(ctx, fmt.Sprintf("marshal body: %s", buf))
	req, err := http.NewRequestWithContext(
		ctx,
		http.MethodPost,
		fmt.Sprintf("https://%s/api/v1/repos/%s/%s/pulls", g.URL, g.Owner, g.Repository),
		bytes.NewReader(buf),
	)
	if err != nil {
		g.logger.Error(ctx, "http request error", err)
		return err
	}
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")
	req.Header.Add("Authorization", "Bearer "+g.Password)

	rsp, err := http.DefaultClient.Do(req)
	if err != nil {
		g.logger.Error(ctx, "failed to call http request", err)
		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)
	}

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

	return nil
}

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

	g.pulls, err = g.GetPulls(ctx, g.URL, g.Owner, g.Repository, g.Password)
	if err != nil {
		g.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 g.pulls {
		if strings.Contains(pull.Title, path) && pull.Base.Ref == branch {
			g.logger.Info(ctx, fmt.Sprintf("PR for %s exists: %s", path, pull.URL))
			prExist = true
			b = pull.Head.Ref
		}
	}
	if !prExist {
		g.logger.Error(ctx, fmt.Sprintf("skip %s since pr does not exist", path))
		return ErrPRNotExist
	}

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

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

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

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

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

	return g.RequestOpen(ctx, branch, path, mod)
}

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

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

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

	for _, pull := range g.pulls {
		if !strings.HasPrefix(pull.Title, "Bump ") || pull.Base.Ref != branch { // 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 (g *Gitea) DeleteBranch(ctx context.Context, url, owner, repo, branch, password string) (*http.Request, error) {
	var buf []byte
	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, fmt.Sprintf("https://%s/api/v1/repos/%s/%s/branches/%s", url, owner, repo, 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", "Bearer "+password)
	return req, err
}

func (g *Gitea) GetPulls(ctx context.Context, url, owner, repo, password string) ([]*giteaPull, error) {
	var pullsAll []*giteaPull
	page := 1

	for {
		pulls := make([]*giteaPull, 0, 10)
		req, err := http.NewRequestWithContext(
			ctx,
			http.MethodGet,
			fmt.Sprintf("https://%s/api/v1/repos/%s/%s/pulls?state=open&page=%v", url, owner, repo, page),
			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", "Bearer "+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 {
				g.logger.Error(ctx, fmt.Sprintf("failed to decode response %s err: %v", buf, err))
				return nil, err
			}
			pullsAll = append(pullsAll, pulls...)
			page++
		case http.StatusNotFound:
			g.logger.Info(ctx, fmt.Sprintf("pull-request is not exist for %s", repo))
			return nil, ErrPRNotExist
		default:
			return nil, fmt.Errorf("unknown error: %s", buf)
		}

		if len(pulls) == 0 {
			break
		}
	}

	return pullsAll, nil
}

func (g *Gitea) checkout(w gogit.Worktree, ref *plumbing.Reference) error {
	ctx := context.Background()
	g.logger.Debug(ctx, "checkout: "+ref.Name().Short())

	if err := w.Checkout(&git.CheckoutOptions{
		Branch: ref.Name(),
		Create: false,
		Force:  true,
		Keep:   false,
	}); err != nil {
		g.logger.Error(ctx, "failed to reset", err)
		return err
	}
	return nil
}