package main

import (
	"bufio"
	"context"
	"errors"
	"fmt"
	"io"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"
)

type RepoResult struct {
	Name           string
	Path           string
	URL            string
	Branch         string // branche configurée
	Pending        bool
	UpToDate       bool
	Offline        bool
	NeedsClone     bool
	HasUpdate      bool   // MAJ disponible (hash local != distant)
	Error          string
	LocalChanges   int
	UntrackedFiles int
	UntrackedList  []string // liste des fichiers non suivis
}

func runGit(args []string, cwd string, timeout time.Duration) (code int, stdout string, stderr string) {
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	fullArgs := append([]string{"-c", "safe.directory=*"}, args...)
	cmd := newGitCmd(ctx, fullArgs, cwd)

	var outBuf, errBuf strings.Builder
	cmd.Stdout = &outBuf
	cmd.Stderr = &errBuf

	err := cmd.Run()
	stdout = strings.TrimSpace(outBuf.String())
	stderr = strings.TrimSpace(errBuf.String())

	if err != nil {
		if ctx.Err() == context.DeadlineExceeded {
			return 1, stdout, "Timeout"
		}
		var exitErr *exec.ExitError
		if errors.As(err, &exitErr) {
			return exitErr.ExitCode(), stdout, stderr
		}
		return -1, stdout, err.Error()
	}
	return 0, stdout, stderr
}

func absRepoPath(rel string) string {
	if filepath.IsAbs(rel) {
		return rel
	}
	return filepath.Join(exeDir(), rel)
}

func checkRemoteOffline(stderr string) bool {
	for _, kw := range []string{"could not resolve", "connection refused", "unable to connect", "timed out", "the remote end hung up", "timeout"} {
		if strings.Contains(strings.ToLower(stderr), kw) {
			return true
		}
	}
	return false
}

func checkRepo(cfg RepoConfig) RepoResult {
	res := RepoResult{Name: cfg.Name, URL: cfg.URL, Branch: cfg.Branch}
	local := absRepoPath(cfg.Path)
	res.Path = local

	if _, err := os.Stat(filepath.Join(local, ".git")); os.IsNotExist(err) {
		// Vérifier que le dépôt distant existe avant de proposer le clone
		code, _, stderr := runGit([]string{"ls-remote", "--exit-code", cfg.URL}, "", 15*time.Second)
		if code != 0 {
			if checkRemoteOffline(stderr) {
				res.Offline = true
				res.Error = "Hors ligne"
				return res
			}
			if strings.Contains(strings.ToLower(stderr), "not found") || strings.Contains(strings.ToLower(stderr), "repository not found") {
				res.Error = "Dépôt introuvable : " + cfg.URL
				return res
			}
			res.Error = "Erreur remote : " + stderr
			return res
		}
		res.NeedsClone = true
		return res
	}

	runGit([]string{"remote", "set-url", "origin", cfg.URL}, local, 10*time.Second)

	// Hash local
	_, localHash, _ := runGit([]string{"rev-parse", "HEAD"}, local, 5*time.Second)
	if localHash == "" {
		res.Error = "Impossible de lire le commit local"
		return res
	}

	// Vérification rapide du remote via ls-remote (timeout court)
	branch := cfg.Branch
	code, lsOut, stderr := runGit([]string{"ls-remote", "origin", "refs/heads/" + branch}, local, 15*time.Second)
	if code != 0 {
		if checkRemoteOffline(stderr) {
			res.Offline = true
			res.Error = "Hors ligne"
			return res
		}
		res.Error = "ls-remote: " + stderr
		return res
	}

	// Extraire le hash distant
	remoteHash := ""
	if lsOut != "" {
		parts := strings.Fields(lsOut)
		if len(parts) > 0 {
			remoteHash = parts[0]
		}
	}
	if remoteHash == "" {
		res.Error = fmt.Sprintf("Branche '%s' introuvable sur le remote", branch)
		return res
	}

	// Comparer les hashs
	if localHash != remoteHash {
		res.HasUpdate = true
	}

	// Modifications locales
	_, status, _ := runGit([]string{"status", "--porcelain"}, local, 5*time.Second)
	if status != "" {
		for _, line := range strings.Split(strings.TrimSpace(status), "\n") {
			if strings.HasPrefix(line, "?? ") {
				res.UntrackedFiles++
				res.UntrackedList = append(res.UntrackedList, strings.TrimPrefix(line, "?? "))
			} else {
				res.LocalChanges++
			}
		}
	}

	res.UpToDate = !res.HasUpdate && res.LocalChanges == 0 && res.UntrackedFiles == 0
	return res
}

func doClone(cfg RepoConfig) error {
	local := absRepoPath(cfg.Path)
	if err := os.MkdirAll(filepath.Dir(local), 0755); err != nil {
		return err
	}

	// Si le dossier n'existe pas ou est vide, clone classique
	entries, _ := os.ReadDir(local)
	if len(entries) == 0 {
		code, _, stderr := runGit([]string{"clone", cfg.URL, local}, "", 300*time.Second)
		if code != 0 {
			return fmt.Errorf("%s", stderr)
		}
		return nil
	}

	// Dossier non-vide sans .git : init + remote + fetch + checkout
	return doCloneInPlace(cfg, local)
}

func doCloneInPlace(cfg RepoConfig, local string) error {
	code, _, stderr := runGit([]string{"init"}, local, 30*time.Second)
	if code != 0 {
		return fmt.Errorf("git init: %s", stderr)
	}

	code, _, stderr = runGit([]string{"remote", "add", "origin", cfg.URL}, local, 10*time.Second)
	if code != 0 {
		// remote existe déjà, mettre à jour l'URL
		runGit([]string{"remote", "set-url", "origin", cfg.URL}, local, 10*time.Second)
	}

	code, _, stderr = runGit([]string{"fetch", "origin"}, local, 5*time.Minute)
	if code != 0 {
		return fmt.Errorf("fetch: %s", stderr)
	}

	branch := cfg.Branch
	code, _, stderr = runGit([]string{"checkout", "origin/" + branch, "-b", branch}, local, 30*time.Second)
	if code != 0 {
		// Branche locale existe déjà
		code, _, stderr = runGit([]string{"checkout", branch}, local, 30*time.Second)
		if code == 0 {
			code, _, stderr = runGit([]string{"reset", "--hard", "origin/" + branch}, local, 30*time.Second)
		}
	}
	if code != 0 {
		return fmt.Errorf("checkout: %s", stderr)
	}
	return nil
}

func doPull(res RepoResult) error {
	_, branch, _ := runGit([]string{"rev-parse", "--abbrev-ref", "HEAD"}, res.Path, 5*time.Second)
	if branch == "" {
		branch = "master"
	}
	code, _, stderr := runGit([]string{"pull", "origin", branch}, res.Path, 120*time.Second)
	if code != 0 {
		return fmt.Errorf("%s", stderr)
	}
	return nil
}

func doCheckout(res RepoResult) error {
	code, _, stderr := runGit([]string{"checkout", "--", "."}, res.Path, 30*time.Second)
	if code != 0 {
		return fmt.Errorf("%s", stderr)
	}
	return nil
}

func doClean(res RepoResult) error {
	code, _, stderr := runGit([]string{"clean", "-fd"}, res.Path, 60*time.Second)
	if code != 0 {
		return fmt.Errorf("%s", stderr)
	}
	return nil
}

// ── Progression Git ───────────────────────────────────────────────────────────

// ProgressInfo contient l'état de progression d'une opération git.
type ProgressInfo struct {
	Phase   string  // ex: "Receiving objects", "Resolving deltas"
	Percent float64 // 0.0 à 1.0
	Current int64
	Total   int64
	Speed   string // ex: "1.2 MiB/s"
}

// ProgressCallback est appelé à chaque mise à jour de la progression.
type ProgressCallback func(ProgressInfo)

// reGitProgress capture les lignes de progression git :
//
//	"Receiving objects:  45% (123/456), 1.20 MiB | 500.00 KiB/s"
//	"Resolving deltas: 100% (89/89), done."
var reGitProgress = regexp.MustCompile(
	`(?i)([\w\s]+):\s+(\d+)%\s+\((\d+)/(\d+)\)(?:.*\|\s*(.+/s))?`,
)

// parseGitProgress analyse une ligne de sortie git et renvoie un ProgressInfo.
func parseGitProgress(line string) (ProgressInfo, bool) {
	m := reGitProgress.FindStringSubmatch(line)
	if m == nil {
		return ProgressInfo{}, false
	}
	pct, _ := strconv.Atoi(m[2])
	cur, _ := strconv.ParseInt(m[3], 10, 64)
	tot, _ := strconv.ParseInt(m[4], 10, 64)
	speed := strings.TrimSpace(m[5])
	return ProgressInfo{
		Phase:   strings.TrimSpace(m[1]),
		Percent: float64(pct) / 100.0,
		Current: cur,
		Total:   tot,
		Speed:   speed,
	}, true
}

// runGitWithProgress exécute une commande git et capture la progression en temps réel.
// Le timeout est désactivé (0) ou très long pour les gros dépôts.
func runGitWithProgress(args []string, cwd string, timeout time.Duration, cb ProgressCallback) (int, string, string) {
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()

	fullArgs := append([]string{"-c", "safe.directory=*"}, args...)
	cmd := newGitCmd(ctx, fullArgs, cwd)

	var outBuf strings.Builder
	cmd.Stdout = &outBuf

	// Pipe stderr pour lire la progression en temps réel
	stderrPipe, err := cmd.StderrPipe()
	if err != nil {
		return -1, "", err.Error()
	}

	if err := cmd.Start(); err != nil {
		return -1, "", err.Error()
	}

	// Lire stderr byte par byte pour détecter les \r (git écrase la ligne)
	var stderrBuf strings.Builder
	reader := bufio.NewReader(stderrPipe)
	var lineBuf strings.Builder

	for {
		b, err := reader.ReadByte()
		if err != nil {
			if err != io.EOF {
				stderrBuf.WriteString(err.Error())
			}
			break
		}
		stderrBuf.WriteByte(b)

		if b == '\r' || b == '\n' {
			line := lineBuf.String()
			lineBuf.Reset()
			if cb != nil && line != "" {
				if info, ok := parseGitProgress(line); ok {
					cb(info)
				}
			}
		} else {
			lineBuf.WriteByte(b)
		}
	}
	// Dernière ligne sans \r\n
	if lineBuf.Len() > 0 && cb != nil {
		if info, ok := parseGitProgress(lineBuf.String()); ok {
			cb(info)
		}
	}

	err = cmd.Wait()
	stdout := strings.TrimSpace(outBuf.String())
	stderr := strings.TrimSpace(stderrBuf.String())

	if err != nil {
		if ctx.Err() == context.DeadlineExceeded {
			return 1, stdout, "Timeout"
		}
		var exitErr *exec.ExitError
		if errors.As(err, &exitErr) {
			return exitErr.ExitCode(), stdout, stderr
		}
		return -1, stdout, err.Error()
	}
	return 0, stdout, stderr
}

// doCloneWithProgress clone un dépôt avec suivi de progression.
func doCloneWithProgress(cfg RepoConfig, cb ProgressCallback) error {
	local := absRepoPath(cfg.Path)
	if err := os.MkdirAll(filepath.Dir(local), 0755); err != nil {
		return err
	}

	// Si le dossier n'existe pas ou est vide, clone classique avec progression
	entries, _ := os.ReadDir(local)
	if len(entries) == 0 {
		code, _, stderr := runGitWithProgress(
			[]string{"clone", "--progress", cfg.URL, local},
			"", 2*time.Hour, cb,
		)
		if code != 0 {
			return fmt.Errorf("%s", stderr)
		}
		return nil
	}

	// Dossier non-vide sans .git : init + remote + fetch avec progression + checkout
	code, _, stderr := runGit([]string{"init"}, local, 30*time.Second)
	if code != 0 {
		return fmt.Errorf("git init: %s", stderr)
	}

	code, _, stderr = runGit([]string{"remote", "add", "origin", cfg.URL}, local, 10*time.Second)
	if code != 0 {
		runGit([]string{"remote", "set-url", "origin", cfg.URL}, local, 10*time.Second)
	}

	code, _, stderr = runGitWithProgress(
		[]string{"fetch", "--progress", "origin"},
		local, 2*time.Hour, cb,
	)
	if code != 0 {
		return fmt.Errorf("fetch: %s", stderr)
	}

	branch := cfg.Branch
	code, _, stderr = runGit([]string{"checkout", "origin/" + branch, "-b", branch}, local, 30*time.Second)
	if code != 0 {
		code, _, stderr = runGit([]string{"checkout", branch}, local, 30*time.Second)
		if code == 0 {
			code, _, stderr = runGit([]string{"reset", "--hard", "origin/" + branch}, local, 30*time.Second)
		}
	}
	if code != 0 {
		return fmt.Errorf("checkout: %s", stderr)
	}
	return nil
}

// doPullWithProgress fait un pull avec suivi de progression.
func doPullWithProgress(res RepoResult, cb ProgressCallback) error {
	_, branch, _ := runGit([]string{"rev-parse", "--abbrev-ref", "HEAD"}, res.Path, 5*time.Second)
	if branch == "" {
		branch = "master"
	}
	code, _, stderr := runGitWithProgress(
		[]string{"pull", "--progress", "origin", branch},
		res.Path, 2*time.Hour, cb,
	)
	if code != 0 {
		return fmt.Errorf("%s", stderr)
	}
	return nil
}