package main

import (
	"bufio"
	"bytes"
	"context"
	"errors"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"

	"view/platform"
)

// ---------------- 从 Git 克隆并添加项目 ----------------

// repoNameFromURL 从 Git 地址推导目录名（支持 https / ssh / 本地路径形式）。
func repoNameFromURL(u string) string {
	s := strings.TrimSpace(u)
	s = strings.TrimRight(s, "/\\")
	s = strings.TrimSuffix(s, ".git")
	if i := strings.LastIndexAny(s, "/:\\"); i >= 0 {
		s = s[i+1:]
	}
	s = regexp.MustCompile(`[<>:"/\\|?*\s]+`).ReplaceAllString(s, "-")
	return strings.Trim(s, "-.")
}

var cloneProgressRe = regexp.MustCompile(`(Counting objects|Compressing objects|Receiving objects|Resolving deltas):\s+(\d+)%`)

// cloneProgress 把 git 各阶段百分比映射到 0-98 的总体进度。
func cloneProgress(line string) (int, bool) {
	m := cloneProgressRe.FindStringSubmatch(line)
	if m == nil {
		return 0, false
	}
	pct, _ := strconv.Atoi(m[2])
	switch m[1] {
	case "Counting objects":
		return 2 + pct*3/100, true
	case "Compressing objects":
		return 5 + pct*5/100, true
	case "Receiving objects":
		return 10 + pct*75/100, true
	default: // Resolving deltas
		return 85 + pct*13/100, true
	}
}

// scanCRLines 以 \r 或 \n 切行：git 进度用回车原地刷新，普通行以换行结束。
func scanCRLines(data []byte, atEOF bool) (int, []byte, error) {
	if atEOF && len(data) == 0 {
		return 0, nil, nil
	}
	if i := bytes.IndexAny(data, "\r\n"); i >= 0 {
		return i + 1, data[:i], nil
	}
	if atEOF {
		return len(data), data, nil
	}
	return 0, nil, nil
}

// CloneProject 把远程仓库克隆到指定父目录后直接加入项目列表。
// 进度通过 analysis:progress 事件复用任务条 / 全屏加载展示。
func (a *App) CloneProject(in CloneInput) (Project, error) {
	if e := a.ready(); e != nil {
		return Project{}, e
	}
	url := strings.TrimSpace(in.URL)
	if url == "" {
		return Project{}, errors.New("URL_REQUIRED")
	}
	parent := strings.TrimSpace(in.ParentDir)
	if st, e := os.Stat(parent); e != nil || !st.IsDir() {
		return Project{}, errors.New("DIR_NOT_FOUND")
	}
	name := strings.TrimSpace(in.Name)
	if name == "" {
		name = repoNameFromURL(url)
	}
	if name == "" {
		return Project{}, errors.New("NAME_REQUIRED")
	}
	target := filepath.Join(parent, name)
	if ents, e := os.ReadDir(target); e == nil && len(ents) > 0 {
		return Project{}, errors.New("TARGET_NOT_EMPTY")
	}

	taskID := "clone-" + name
	emitP := func(stage string, progress int, key string) {
		a.emit("analysis:progress", TaskEvent{TaskID: taskID, Stage: stage, Progress: progress, MessageKey: key, Params: map[string]any{"project": name}})
	}
	emitP("cloning", 1, "task.cloning")

	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Minute)
	defer cancel()
	cmd := exec.CommandContext(ctx, "git", "clone", "--progress", url, target)
	// 禁止 git 弹出交互式凭据询问，私有仓库直接快速失败
	cmd.Env = append(os.Environ(), "GIT_TERMINAL_PROMPT=0", "GCM_INTERACTIVE=never")
	platform.ConfigureHidden(cmd)
	stderr, e := cmd.StderrPipe()
	if e != nil {
		emitP("error", 100, "task.cloneFailed")
		return Project{}, e
	}
	if e := cmd.Start(); e != nil {
		emitP("error", 100, "task.cloneFailed")
		a.store.Log("error", "项目", "Git 克隆失败", url+" | "+e.Error())
		return Project{}, e
	}
	sc := bufio.NewScanner(stderr)
	sc.Split(scanCRLines)
	tail := []string{}
	for sc.Scan() {
		line := strings.TrimSpace(sc.Text())
		if line == "" {
			continue
		}
		if len(tail) >= 6 {
			tail = tail[1:]
		}
		tail = append(tail, line)
		if p, ok := cloneProgress(line); ok {
			emitP("cloning", p, "task.cloning")
		}
	}
	if e := cmd.Wait(); e != nil {
		_ = os.RemoveAll(target) // 清掉半成品目录（克隆前已确认为空/不存在）
		msg := strings.Join(tail, "\n")
		a.store.Log("error", "项目", "Git 克隆失败", url+" | "+msg)
		emitP("error", 100, "task.cloneFailed")
		if msg != "" {
			return Project{}, errors.New(msg)
		}
		return Project{}, e
	}
	p, e := a.SaveProject(0, ProjectInput{Name: name, Path: target, Description: in.Description, GroupID: in.GroupID})
	if e != nil {
		emitP("error", 100, "task.cloneFailed")
		return p, e
	}
	a.store.Log("info", "项目", "Git 克隆成功", url+" -> "+target)
	emitP("completed", 100, "task.cloneDone")
	return p, nil
}