package main

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"os/exec"
	"os/user"
	"path/filepath"
	"strings"
	"text/template"
	"time"

	"git.unistack.org/unistack-org/pkgdash/internal/configcli"
	"git.unistack.org/unistack-org/pkgdash/internal/modules"
	"git.unistack.org/unistack-org/pkgdash/internal/source"
	"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"
	"github.com/jdx/go-netrc"
	yamlcodec "go.unistack.org/micro-codec-yaml/v4"
	envconfig "go.unistack.org/micro-config-env/v4"
	fileconfig "go.unistack.org/micro-config-file/v4"
	microflag "go.unistack.org/micro-config-flag/v4"
	"go.unistack.org/micro/v4/config"
	"go.unistack.org/micro/v4/logger"
	"go.unistack.org/micro/v4/logger/slog"
	"go.unistack.org/micro/v4/options"
	"golang.org/x/mod/modfile"
	"golang.org/x/mod/semver"
)

// https://docs.github.com/ru/code-security/dependabot/dependabot-version-updates/configuration-options-for-the-dependabot.yml-file

var initMsg = `
	Pkgdashcli allows you to define a version update for a dependency and start 
	merge requests in version control systems.
	
	Usage:
		pkgdashcli --command {{command}} --path {{name of dep}}

	Commands:
		checkupdate							   | CheckUpdate collects a list of dependencies with the latest updates.
		list 								   | Returns a list of PR for this repository with update dependencies.
		update      --path {{name of one dep or empty for update all dep}} | Creates a PR with the specified dependency update in path or creates a PR with dependency updates for all modules if path is empty.
		close       --path {{name of one dep or empty for close all pr}}   | Closes the PR for the specified dependency or closes all PRs with dependency updates if path is empty .

	Flags:
		--command | The command to execute
		--path	  | The name of the module to create/close the PR, if empty, the command is executed for all modules.
`

var (
	DefaultPullRequestTitle = `Bump {{.Name}} from {{.VersionOld}} to {{.VersionNew}}`
	DefaultPullRequestBody  = `Bumps {{.Name}} from {{.VersionOld}} to {{.VersionNew}}`
)

var (
	configFiles = []string{
		"dependabot.yml",
		"pkgdashcli.yml",
		"pkgdashcli.yaml",
	}
	configDirs = []string{
		".gitea",
		".github",
		".gitlab",
	}
	repoMgmt = map[string]string{
		".gitea":  "gitea",
		".gogs":   "gogs",
		".github": "github",
		".gitlab": "gitlab",
	}
	repoAPI = map[string]string{
		".gitea":  "git.unistack.org",
		".gogs":   "gogs",
		".github": "github.com/unistack-org",
		".gitlab": "gitlab.mtsbank.ru",
	}
)

type Data struct {
	Modules map[string]modules.Update
}

func main() {
	var err error

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	logger.DefaultLogger = slog.NewLogger()

	if err = logger.DefaultLogger.Init(logger.WithCallerSkipCount(3), logger.WithLevel(logger.DebugLevel)); err != nil {
		logger.Error(ctx, fmt.Sprintf("logger init error: %v", err))
	}

	cfg := configcli.NewConfig()

	if err = config.Load(ctx,
		[]config.Config{
			config.NewConfig(
				config.Struct(cfg),
			),
			envconfig.NewConfig(
				config.Struct(cfg),
			),
		},
		config.LoadOverride(true),
	); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("failed to load config: %v", err))
	}

	for _, configDir := range configDirs {
		for _, configFile := range configFiles {
			path := filepath.Join(configDir, configFile)
			if _, err = os.Stat(path); os.IsNotExist(err) {
				continue
			}

			c := fileconfig.NewConfig(
				config.AllowFail(false),
				config.Struct(cfg),
				options.Codec(yamlcodec.NewCodec()),
				fileconfig.Path(path),
			)
			err = c.Init()
			if err != nil {
				logger.Error(ctx, fmt.Sprintf("failed to init config: %v", err))
			}
			if err = c.Load(ctx, config.LoadOverride(true)); err != nil {
				logger.Error(ctx, fmt.Sprintf("failed to load config: %v", err))
			}
		}
	}

	if cfg.PullRequestBody == "" {
		cfg.PullRequestBody = DefaultPullRequestBody
	}

	if cfg.PullRequestTitle == "" {
		cfg.PullRequestTitle = DefaultPullRequestTitle
	}

	cliCfg := &configcli.Cli{}
	c := microflag.NewConfig(config.Struct(cliCfg), microflag.FlagErrorHandling(flag.ContinueOnError))

	if err = c.Init(); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("init cli cfg failed: %v", err))
	}

	if err = c.Load(ctx); err != nil {
		logger.Fatal(ctx, fmt.Sprintf("load cli cfg failed: %v", err))
	}

	if cliCfg.Path == "" && cliCfg.Command == "" {
		fmt.Print(initMsg)
		return
	}

	path := "."
	if len(os.Args) > 1 {
		path = os.Args[1]
	}

	name, err := modules.FindModFile(path)
	if err != nil {
		panic(err)
	}
	buf, err := os.ReadFile(name)
	if err != nil {
		panic(err)
	}
	mfile, err := modfile.Parse(name, buf, nil)
	if err != nil {
		panic(err)
	}

	mvs := make(map[string]modules.Update)

	updateOptions := modules.UpdateOptions{
		Pre:     cfg.UpdateOpt.Pre,
		Major:   cfg.UpdateOpt.Major,
		UpMajor: cfg.UpdateOpt.UpMajor,
		Cached:  cfg.UpdateOpt.Cached,
		OnUpdate: func(u modules.Update) {
			var modpath string // new mod path with major
			if u.Err != nil {
				logger.Error(ctx, fmt.Sprintf("%s: failed: %v", u.Module.Path, u.Err))
				return
			}
			modpath = u.Module.Path
			v := semver.Major(u.Version)
			p := modules.ModPrefix(modpath)
			if !strings.HasPrefix(u.Module.Version, v) && v != "v1" && v != "v0" {
				switch strings.HasPrefix(u.Module.Path, "gopkg.in") {
				case true:
					modpath = p + "." + v
				case false:
					modpath = p + "/" + v
				}
			}
			mvs[modpath] = u
		},
	}

	for _, req := range mfile.Require {
		updateOptions.Modules = append(updateOptions.Modules, req.Mod)
	}

	modules.Updates(updateOptions)

	if err = getRepoMgmt(ctx, cfg); err != nil { // Filling in empty config fields.
		logger.Error(ctx, err.Error())
	}

	gitSource := source.NewSourceControl(*cfg)

	Execute(ctx, gitSource, mvs, *cliCfg, *cfg)

	logger.Info(ctx, "Pkgdash successfully updated dependencies")
}

func Execute(ctx context.Context, gitSource source.SourceControl, mvs map[string]modules.Update, cliCfg configcli.Cli, cfg configcli.Config) {
	var mod modules.Update
	var ok bool
	var path string
	prList := make(map[string]map[string]string)

	switch cliCfg.Command {
	case "checkupdate":
		js, err := json.Marshal(mvs)
		fmt.Println(fmt.Sprintf(`Modules get update: %s, %s`, js, err))
	case "update":
		if cliCfg.Path != "" { // update one dep
			path = cliCfg.Path
			if mod, ok = mvs[path]; !ok {
				logger.Fatal(ctx, fmt.Sprintf("For %s update not exist", path))
			}
			logger.Debug(ctx, fmt.Sprintf("Start update %s from %s to %s", path, mod.Module.Version, mod.Version))
			for _, branch := range cfg.Branches {
				if err := gitSource.RequestOpen(ctx, branch, path, mod); err != nil {
					logger.Fatal(ctx, fmt.Sprintf("failed to create pr: %v", err))
				}
			}
			logger.Debug(ctx, fmt.Sprintf("Update successful for %s", path))
			return
		}
		for _, branch := range cfg.Branches { // update all dep
			for path, mod = range mvs {
				logger.Debug(ctx, fmt.Sprintf("Start update %s from %s to %s", path, mod.Module.Version, mod.Version))
				err := gitSource.RequestOpen(ctx, branch, path, mod)
				if err != nil {
					if strings.Contains(err.Error(), "already exists") {
						logger.Debug(ctx, fmt.Sprintf("skip %s, branch already exists", path))
						continue
					}
					logger.Fatal(ctx, fmt.Sprintf("failed to create pr: %v", err))
				}
				logger.Debug(ctx, fmt.Sprintf("Update successful for %s", path))
			}
		}
	case "close":
		if cliCfg.Path != "" { // close one dep
			path = cliCfg.Path
			logger.Debug(ctx, fmt.Sprintf("Start close for %s", path))
			for _, branch := range cfg.Branches {
				if err := gitSource.RequestClose(ctx, branch, path); err != nil {
					logger.Fatal(ctx, fmt.Sprintf("failed to close pr: %v", err))
				}
			}
			logger.Debug(ctx, fmt.Sprintf("Close successful for %s", path))
			return
		}
		for _, branch := range cfg.Branches {
			logger.Info(ctx, fmt.Sprintf("Start getting pr for %s", branch))
			rMap, err := gitSource.RequestList(ctx, branch)
			if err != nil {
				logger.Fatal(ctx, fmt.Sprintf("Error with getting pr list for branch: %s", branch))
			}

			logger.Info(ctx, fmt.Sprintf("for %s:\n%s", branch, rMap))
			logger.Info(ctx, fmt.Sprintf("Start close pr for base branch %s", branch))

			for path, _ = range rMap {
				logger.Debug(ctx, fmt.Sprintf("Start close for %s", path))
				if err = gitSource.RequestClose(ctx, branch, path); err != nil {
					logger.Fatal(ctx, fmt.Sprintf("failed to close pr: %v", err))
				}
				logger.Debug(ctx, fmt.Sprintf("Close successful for %s", path))
			}
		}
	case "list":
		for _, branch := range cfg.Branches {
			rMap, err := gitSource.RequestList(ctx, branch)
			if err != nil {
				logger.Fatal(ctx, fmt.Sprintf("RequestList: error %s", err))
			}

			prList[branch] = rMap
		}
		js, err := json.Marshal(prList)
		if err != nil {
			logger.Error(ctx, fmt.Sprintf("error: %s", err))
		}
		fmt.Println(fmt.Sprintf("for %s:\n%s", cfg.Source.Repository, js))
	default:
		fmt.Print(initMsg)
	}
}

func getRepoMgmt(ctx context.Context, cfg *configcli.Config) error {
	wd, err := os.Getwd()
	if err != nil {
		return err
	}

	p := filepath.Clean(wd)
	for _, configDir := range configDirs {
		_, err := os.Stat(filepath.Join(p, configDir))
		if name, ok := repoMgmt[configDir]; ok && cfg.Source.TypeGit == "" && err == nil {
			cfg.Source.TypeGit = name
		}
		if api, ok := repoAPI[configDir]; ok && cfg.Source.APIURL == "" && err == nil {
			cfg.Source.APIURL = api
		}
	}
	if p == "/" && cfg.Source.TypeGit == "" && cfg.Source.APIURL == "" {
		return fmt.Errorf("unknown")
	}
	p = filepath.Clean(filepath.Join(p, ".."))

	usr, err := user.Current()
	if err != nil {
		logger.Fatal(ctx, fmt.Sprintf("pkgdash/main can t get info about user: %s", err))
	}
	n, err := netrc.Parse(filepath.Join(usr.HomeDir, ".netrc"))
	if err != nil {
		logger.Error(ctx, "pkgdash/main can t parse .netrc: %s", err)
	}

	if cfg.Source.Owner == "" {
		cfg.Source.Owner = n.Machine(cfg.Source.APIURL).Get("login")
	}
	if cfg.Source.Username == "" {
		cfg.Source.Username = n.Machine(cfg.Source.APIURL).Get("login")
	}
	if cfg.Source.Password == "" {
		cfg.Source.Password = n.Machine(cfg.Source.APIURL).Get("password")
	}
	return nil
}

func giteaPullRequest(ctx context.Context, cfg *configcli.Config, branch string, mods map[string]modules.Update) error {
	envAPIURL := os.Getenv("GITHUB_API_URL")
	envREPOSITORY := os.Getenv("GITHUB_REPOSITORY")
	envTOKEN := os.Getenv("GITHUB_TOKEN")

	var buf []byte
	var err error

	tplTitle, err := template.New("pull_request_title").Parse(cfg.PullRequestTitle)
	if err != nil {
		logger.Fatal(ctx, "failed to parse template: %v", err)
	}

	wTitle := bytes.NewBuffer(nil)

	tplBody, err := template.New("pull_request_body").Parse(cfg.PullRequestBody)
	if err != nil {
		logger.Fatal(ctx, "failed to parse template: %v", err)
	}

	wBody := bytes.NewBuffer(nil)

	repo, err := git.PlainOpenWithOptions(".", &git.PlainOpenOptions{DetectDotGit: true})
	if err != nil {
		logger.Fatal(ctx, "failed to open repo: %v", err)
	}

	if err = repo.FetchContext(ctx, &git.FetchOptions{
		Auth:  &httpauth.BasicAuth{Username: envTOKEN, Password: envTOKEN},
		Force: true,
	}); err != nil && err != git.NoErrAlreadyUpToDate {
		logger.Fatal(ctx, "failed to fetch repo: %v", err)
	}

	var headRef *plumbing.Reference
	refIter, err := repo.Branches()
	if err != nil {
		logger.Fatal(ctx, "failed to get branches: %v", err)
	}
	for {
		ref, err := refIter.Next()
		if err != nil {
			break
		}
		if ref.Name().String() == branch {
			headRef = ref
			break
		}
	}
	refIter.Close()

	if headRef == nil {
		logger.Fatal(ctx, "failed to get repo branch head")
	}

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

	wtree, err := repo.Worktree()
	if err != nil {
		logger.Fatal(ctx, "failed to get worktree: %v", err)
	}

	type giteaPull struct {
		URL   string `json:"url"`
		Title string `json:"title"`
		Base  struct {
			Ref string `json:"ref"`
		} `json:"base"`
		ID int64 `json:"id"`
	}

	var pulls []*giteaPull
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, envAPIURL+"/repos/"+envREPOSITORY+"/pulls?state=open&token="+envTOKEN, nil)
	if err != nil {
		return err
	}
	req.Header.Add("Accept", "application/json")
	req.Header.Add("Content-Type", "application/json")

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

	buf, _ = io.ReadAll(rsp.Body)
	if rsp.StatusCode != http.StatusOK {
		return fmt.Errorf("unknown error: %s", buf)
	}

	if err = json.Unmarshal(buf, &pulls); err != nil {
		logger.Fatal(ctx, "failed to decode response %s err: %v", buf, err)
	}

	for path := range mods {
		for _, pull := range pulls {
			if strings.Contains(pull.Title, path) && pull.Base.Ref == branch {
				logger.Info(ctx, "skip %s as pr already exists %s", path, pull.URL)
				delete(mods, path)
			}
		}
	}

	for path, mod := range mods {
		wTitle.Reset()
		wBody.Reset()

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

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

		if err = wtree.PullContext(ctx, &git.PullOptions{
			Auth:  &httpauth.BasicAuth{Username: envTOKEN, Password: envTOKEN},
			Depth: 1,
			//	RemoteURL :
			Force:      true,
			RemoteName: "origin",
		}); err != nil && err != git.NoErrAlreadyUpToDate {
			logger.Fatal(ctx, "failed to pull repo: %v", err)
		}

		logger.Info(ctx, "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 {
			logger.Fatal(ctx, "failed to checkout tree: %v", err)
		}

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

		var cmd *exec.Cmd
		var out []byte

		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, "failed to run go mod edit: %s err: %v", out, err)
		}

		cmd = exec.CommandContext(ctx, epath, "mod", "tidy")
		if out, err = cmd.CombinedOutput(); err != nil {
			logger.Fatal(ctx, "failed to run go mod tidy: %s err: %v", out, err)
		}

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

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

		// newref := plumbing.NewHashReference(plumbing.ReferenceName(fmt.Sprintf("refs/heads/pkgdash/go_modules/%s-%s", path, mod.Version)), headRef.Hash())

		/*
			if err = repo.Storer.SetReference(newref); err != nil {
				logger.Fatal(ctx, "failed to create repo branch: %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))

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

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

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

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

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

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

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

		req, err := http.NewRequestWithContext(ctx, http.MethodPost, envAPIURL+"/repos/"+envREPOSITORY+"/pulls?token="+envTOKEN, bytes.NewReader(buf))
		if err != nil {
			return err
		}
		req.Header.Add("Accept", "application/json")
		req.Header.Add("Content-Type", "application/json")

		rsp, err := http.DefaultClient.Do(req)
		if err != nil {
			return err
		}
		if rsp.StatusCode != http.StatusCreated {
			buf, _ = io.ReadAll(rsp.Body)
			return fmt.Errorf("unknown error: %s", buf)
		}

	}

	return nil
}