// projects.go 读取 Cursor 的项目历史（用户打开过哪些项目）。
// 两个来源：
//  1. workspaceStorage/<hash>/workspace.json — 每个打开过的项目一个目录，mtime 即最后打开时间
//  2. state.vscdb 的 history.recentlyOpenedPathsList — 最近打开列表（与 Cursor UI 一致）
package cursor

import (
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/url"
	"os"
	"path/filepath"
	"runtime"
	"sort"
	"strings"

	_ "modernc.org/sqlite"
)

// ProjectEntry 表示一个用户打开过的项目。
type ProjectEntry struct {
	Path       string `json:"path"`
	LastOpened int64  `json:"lastOpenedMs"`
}

// cursorUserDir 返回 Cursor 用户数据目录（.../Cursor/User）。
func cursorUserDir() (string, error) {
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("获取用户目录失败: %w", err)
	}
	switch runtime.GOOS {
	case "darwin":
		return filepath.Join(homeDir, "Library", "Application Support", "Cursor", "User"), nil
	case "windows":
		appData := strings.TrimSpace(os.Getenv("APPDATA"))
		if appData == "" {
			appData = filepath.Join(homeDir, "AppData", "Roaming")
		}
		return filepath.Join(appData, "Cursor", "User"), nil
	case "linux":
		configDir := strings.TrimSpace(os.Getenv("XDG_CONFIG_HOME"))
		if configDir == "" {
			configDir = filepath.Join(homeDir, ".config")
		}
		return filepath.Join(configDir, "Cursor", "User"), nil
	default:
		return "", fmt.Errorf("不支持的系统: %s", runtime.GOOS)
	}
}

// ListRecentProjects 返回用户打开过的项目列表，按最后打开时间倒序。
// 只保留磁盘上仍然存在的路径。
func ListRecentProjects() ([]ProjectEntry, error) {
	userDir, err := cursorUserDir()
	if err != nil {
		return nil, err
	}
	if _, err := os.Stat(userDir); err != nil {
		return nil, fmt.Errorf("未找到 Cursor 用户数据目录: %s", userDir)
	}

	entries := make(map[string]ProjectEntry)
	collectWorkspaceStorageProjects(userDir, entries)
	collectRecentlyOpenedProjects(userDir, entries)

	result := make([]ProjectEntry, 0, len(entries))
	for _, entry := range entries {
		if info, err := os.Stat(entry.Path); err == nil && info.IsDir() {
			result = append(result, entry)
		}
	}
	sort.Slice(result, func(i, j int) bool {
		return result[i].LastOpened > result[j].LastOpened
	})
	return result, nil
}

// collectWorkspaceStorageProjects 从 workspaceStorage 目录收集项目。
func collectWorkspaceStorageProjects(userDir string, entries map[string]ProjectEntry) {
	storageRoot := filepath.Join(userDir, "workspaceStorage")
	dirEntries, err := os.ReadDir(storageRoot)
	if err != nil {
		return
	}
	for _, dirEntry := range dirEntries {
		if !dirEntry.IsDir() {
			continue
		}
		dirPath := filepath.Join(storageRoot, dirEntry.Name())
		raw, err := os.ReadFile(filepath.Join(dirPath, "workspace.json"))
		if err != nil {
			continue
		}
		var payload struct {
			Folder string `json:"folder"`
		}
		if err := json.Unmarshal(raw, &payload); err != nil {
			continue
		}
		path := projectPathFromURI(payload.Folder)
		if path == "" {
			continue
		}
		path = filepath.Clean(path)
		lastOpened := projectDirModTime(dirPath, path)
		if existing, ok := entries[path]; !ok || lastOpened > existing.LastOpened {
			entries[path] = ProjectEntry{Path: path, LastOpened: lastOpened}
		}
	}
}

// collectRecentlyOpenedProjects 从 state.vscdb 读取最近打开列表。
func collectRecentlyOpenedProjects(userDir string, entries map[string]ProjectEntry) {
	dbPath := filepath.Join(userDir, "globalStorage", "state.vscdb")
	if _, err := os.Stat(dbPath); err != nil {
		return
	}
	snapshot, err := copyToTemp(dbPath)
	if err != nil {
		return
	}
	defer os.Remove(snapshot)

	db, err := sql.Open("sqlite", snapshot)
	if err != nil {
		return
	}
	defer db.Close()

	var raw string
	if err := db.QueryRow(
		"SELECT value FROM ItemTable WHERE key = 'history.recentlyOpenedPathsList'",
	).Scan(&raw); err != nil {
		return
	}
	var payload struct {
		Entries []struct {
			FolderURI string `json:"folderUri"`
		} `json:"entries"`
	}
	if err := json.Unmarshal([]byte(raw), &payload); err != nil {
		return
	}
	for _, item := range payload.Entries {
		path := projectPathFromURI(item.FolderURI)
		if path == "" {
			continue
		}
		path = filepath.Clean(path)
		lastOpened := projectDirModTime(path, path)
		if existing, ok := entries[path]; !ok || lastOpened > existing.LastOpened {
			entries[path] = ProjectEntry{Path: path, LastOpened: lastOpened}
		}
	}
}

// DeleteProjectRecord 从 Cursor 的项目记录中删除指定项目，清理两处：
//  1. workspaceStorage 中 folder 指向该项目的目录（整个 hash 目录，含该项目聊天记录）
//  2. state.vscdb 的 history.recentlyOpenedPathsList 对应条目
//
// Cursor 运行时直接拒绝：state.vscdb 为 Cursor 主数据库，运行中写入可能锁冲突或被回写覆盖。
func DeleteProjectRecord(projectPath string) error {
	projectPath = filepath.Clean(strings.TrimSpace(projectPath))
	if projectPath == "" || projectPath == "." {
		return fmt.Errorf("无效的项目路径")
	}
	if IsCursorRunning() {
		return fmt.Errorf("Cursor 正在运行，请先关闭 Cursor 后重试")
	}
	userDir, err := cursorUserDir()
	if err != nil {
		return err
	}
	if _, err := os.Stat(userDir); err != nil {
		return fmt.Errorf("未找到 Cursor 用户数据目录: %s", userDir)
	}

	storageRemoved, storageErr := removeWorkspaceStorageEntries(userDir, projectPath)
	entryRemoved, entryErr := removeRecentlyOpenedEntry(userDir, projectPath)
	if storageErr != nil || entryErr != nil {
		return fmt.Errorf("删除不完整（workspaceStorage: %d 处, %v；最近打开列表: %d 处, %v）",
			storageRemoved, storageErr, entryRemoved, entryErr)
	}
	if storageRemoved+entryRemoved == 0 {
		return fmt.Errorf("未找到项目 %s 的记录", projectPath)
	}
	return nil
}

// removeWorkspaceStorageEntries 删除 folder 指向该项目的 workspaceStorage hash 目录。
// 单个目录删除失败不中断循环，错误聚合返回。
func removeWorkspaceStorageEntries(userDir string, projectPath string) (int, error) {
	storageRoot := filepath.Join(userDir, "workspaceStorage")
	dirEntries, err := os.ReadDir(storageRoot)
	if err != nil {
		if os.IsNotExist(err) {
			return 0, nil
		}
		return 0, fmt.Errorf("读取 workspaceStorage 失败: %w", err)
	}
	removed := 0
	var removeErrs []error
	for _, dirEntry := range dirEntries {
		if !dirEntry.IsDir() {
			continue
		}
		dirPath := filepath.Join(storageRoot, dirEntry.Name())
		raw, err := os.ReadFile(filepath.Join(dirPath, "workspace.json"))
		if err != nil {
			continue
		}
		var payload struct {
			Folder string `json:"folder"`
		}
		if err := json.Unmarshal(raw, &payload); err != nil {
			continue
		}
		if path := projectPathFromURI(payload.Folder); path != "" && samePath(filepath.Clean(path), projectPath) {
			if err := os.RemoveAll(dirPath); err != nil {
				removeErrs = append(removeErrs, fmt.Errorf("删除 %s 失败: %w", dirPath, err))
				continue
			}
			removed++
		}
	}
	return removed, errors.Join(removeErrs...)
}

// removeRecentlyOpenedEntry 从 state.vscdb 的最近打开列表中移除该项目。
// 返回删除条目数；读取或写入失败时返回错误（如 Cursor 占用数据库导致的 SQLITE_BUSY）。
func removeRecentlyOpenedEntry(userDir string, projectPath string) (int, error) {
	dbPath := filepath.Join(userDir, "globalStorage", "state.vscdb")
	if _, err := os.Stat(dbPath); err != nil {
		if os.IsNotExist(err) {
			return 0, nil
		}
		return 0, fmt.Errorf("访问 state.vscdb 失败: %w", err)
	}
	db, err := sql.Open("sqlite", dbPath)
	if err != nil {
		return 0, fmt.Errorf("打开 state.vscdb 失败: %w", err)
	}
	defer db.Close()

	var raw string
	if err := db.QueryRow(
		"SELECT value FROM ItemTable WHERE key = 'history.recentlyOpenedPathsList'",
	).Scan(&raw); err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return 0, nil
		}
		return 0, fmt.Errorf("读取最近打开列表失败: %w", err)
	}
	var payload struct {
		Entries []struct {
			FolderURI string `json:"folderUri"`
		} `json:"entries"`
	}
	if err := json.Unmarshal([]byte(raw), &payload); err != nil {
		return 0, fmt.Errorf("解析最近打开列表失败: %w", err)
	}
	kept := make([]struct {
		FolderURI string `json:"folderUri"`
	}, 0, len(payload.Entries))
	removed := 0
	for _, item := range payload.Entries {
		path := projectPathFromURI(item.FolderURI)
		if path != "" && samePath(filepath.Clean(path), projectPath) {
			removed++
			continue
		}
		kept = append(kept, item)
	}
	if removed == 0 {
		return 0, nil
	}
	updated, err := json.Marshal(map[string]any{"entries": kept})
	if err != nil {
		return 0, fmt.Errorf("序列化最近打开列表失败: %w", err)
	}
	if _, err := db.Exec(
		"UPDATE ItemTable SET value = ? WHERE key = 'history.recentlyOpenedPathsList'",
		string(updated),
	); err != nil {
		return 0, fmt.Errorf("写入 state.vscdb 失败（Cursor 可能占用数据库）: %w", err)
	}
	return removed, nil
}

// projectPathFromURI 将 file:/// URI 转换为本地路径；非 file URI 返回空。
func projectPathFromURI(raw string) string {
	raw = strings.TrimSpace(raw)
	if !strings.HasPrefix(raw, "file://") {
		return ""
	}
	parsed, err := url.Parse(raw)
	if err != nil {
		return ""
	}
	path, err := url.PathUnescape(parsed.Path)
	if err != nil {
		return ""
	}
	path = strings.TrimPrefix(path, "/")
	if len(path) >= 2 && path[1] == ':' {
		// Windows 盘符路径已就绪（如 d:/Project/x）。
		return path
	}
	return "/" + path
}

// projectDirModTime 返回目录 mtime；失败时返回 0。
func projectDirModTime(dirs ...string) int64 {
	for _, dir := range dirs {
		if info, err := os.Stat(dir); err == nil {
			return info.ModTime().UnixMilli()
		}
	}
	return 0
}

// copyToTemp 复制文件到临时目录，供只读 SQLite 打开，避免源库 WAL 锁。
func copyToTemp(src string) (string, error) {
	in, err := os.Open(src)
	if err != nil {
		return "", err
	}
	defer in.Close()
	out, err := os.CreateTemp("", "cursor-state-*.vscdb")
	if err != nil {
		return "", err
	}
	defer out.Close()
	if _, err := io.Copy(out, in); err != nil {
		os.Remove(out.Name())
		return "", err
	}
	return out.Name(), nil
}