package file

import (
	"context"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/plugin"
)

// Plugin provides sandboxed file read/write inside the configured data directory.
type Plugin struct {
	dataDir string
}

func New() *Plugin { return &Plugin{} }

func (p *Plugin) Name() string        { return "file" }
func (p *Plugin) Version() string     { return "1.0.0" }
func (p *Plugin) Description() string { return "文件操作" }
func (p *Plugin) Close() error        { return nil }
func (p *Plugin) Enabled() bool       { return p.dataDir != "" }

func (p *Plugin) Init(_ context.Context, cfg plugin.PluginConfig) error {
	p.dataDir = cfg.DataDir
	if p.dataDir == "" {
		p.dataDir = "data/files"
	}
	return os.MkdirAll(p.dataDir, 0o755)
}

func (p *Plugin) Tools() []plugin.ToolDefinition {
	return []plugin.ToolDefinition{
		{
			Name:        "file_read",
			Description: "Read a text file from the data directory.",
			Parameters: map[string]any{
				"type": "object",
				"properties": map[string]any{
					"path": map[string]string{"type": "string", "description": "Relative path inside the data directory"},
				},
				"required": []string{"path"},
			},
		},
		{
			Name:        "file_write",
			Description: "Write text to a file in the data directory (overwrites).",
			Parameters: map[string]any{
				"type": "object",
				"properties": map[string]any{
					"path":    map[string]string{"type": "string", "description": "Relative path inside the data directory"},
					"content": map[string]string{"type": "string", "description": "Text content to write"},
				},
				"required": []string{"path", "content"},
			},
		},
		{
			Name:        "file_list",
			Description: "List files in the data directory (or a subdirectory).",
			Parameters: map[string]any{
				"type": "object",
				"properties": map[string]any{
					"path": map[string]string{"type": "string", "description": "Relative directory path (default: root)"},
				},
			},
		},
	}
}

func (p *Plugin) Execute(_ context.Context, toolName string, params map[string]any) (string, error) {
	rel, _ := params["path"].(string)
	path, err := p.resolve(rel)
	if err != nil {
		return "", err
	}

	switch toolName {
	case "file_read":
		data, err := os.ReadFile(path)
		if err != nil {
			return "", fmt.Errorf("read: %w", err)
		}
		text := string(data)
		if runes := []rune(text); len(runes) > 4000 {
			text = string(runes[:4000]) + "\n…（文件过长已截断）"
		}
		return text, nil

	case "file_write":
		content, _ := params["content"].(string)
		if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
			return "", err
		}
		if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
			return "", fmt.Errorf("write: %w", err)
		}
		return fmt.Sprintf("已写入 %s（%d 字节）", rel, len(content)), nil

	case "file_list":
		entries, err := os.ReadDir(path)
		if err != nil {
			return "", fmt.Errorf("list: %w", err)
		}
		if len(entries) == 0 {
			return "（空目录）", nil
		}
		var sb strings.Builder
		for _, e := range entries {
			name := e.Name()
			if e.IsDir() {
				name += "/"
			}
			sb.WriteString(name + "\n")
		}
		return sb.String(), nil
	}
	return "", fmt.Errorf("unknown tool %q", toolName)
}

// resolve maps a relative path into the sandbox and rejects escapes.
func (p *Plugin) resolve(rel string) (string, error) {
	clean := filepath.Clean("/" + rel) // force relative interpretation
	full := filepath.Join(p.dataDir, clean)
	root, _ := filepath.Abs(p.dataDir)
	abs, _ := filepath.Abs(full)
	if abs != root && !strings.HasPrefix(abs, root+string(filepath.Separator)) {
		return "", fmt.Errorf("path escapes data directory")
	}
	return full, nil
}