package filetool

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

	"laodingbot/internal/logger"
)

type Tool struct {
	allowedDirs []string
	log         *logger.Logger
}

func New(allowedDirs []string, log *logger.Logger) *Tool {
	normalized := make([]string, 0, len(allowedDirs))
	for _, dir := range allowedDirs {
		abs, err := filepath.Abs(strings.TrimSpace(dir))
		if err == nil {
			normalized = append(normalized, filepath.Clean(abs))
		}
	}
	if log != nil {
		log.Infof("file tool initialized allowed_dirs=%d", len(normalized))
	}
	return &Tool{allowedDirs: normalized, log: log}
}

func (t *Tool) Name() string { return "file" }

func (t *Tool) Description() string {
	return "File operations with command format: read <path> | write <path>\\n<content>"
}

func (t *Tool) Call(_ context.Context, input string) (string, error) {
	input = strings.TrimSpace(input)
	if t.log != nil {
		t.log.Debugf("file tool call input_len=%d", len(input))
	}
	if strings.HasPrefix(input, "read ") {
		path := strings.TrimSpace(strings.TrimPrefix(input, "read "))
		resolved, err := t.resolveAllowed(path)
		if err != nil {
			if t.log != nil {
				t.log.Warnf("file read denied path=%s err=%v", path, err)
			}
			return "", err
		}
		b, err := os.ReadFile(resolved)
		if err != nil {
			if t.log != nil {
				t.log.Errorf("file read failed path=%s err=%v", resolved, err)
			}
			return "", err
		}
		if t.log != nil {
			t.log.Infof("file read success path=%s bytes=%d", resolved, len(b))
		}
		return string(b), nil
	}

	if strings.HasPrefix(input, "write ") {
		parts := strings.SplitN(input, "\n", 2)
		if len(parts) < 2 {
			return "", fmt.Errorf("write requires content in second line")
		}
		path := strings.TrimSpace(strings.TrimPrefix(parts[0], "write "))
		resolved, err := t.resolveAllowed(path)
		if err != nil {
			if t.log != nil {
				t.log.Warnf("file write denied path=%s err=%v", path, err)
			}
			return "", err
		}
		if err := os.MkdirAll(filepath.Dir(resolved), 0o755); err != nil {
			if t.log != nil {
				t.log.Errorf("file write mkdir failed path=%s err=%v", resolved, err)
			}
			return "", err
		}
		if err := os.WriteFile(resolved, []byte(parts[1]), 0o644); err != nil {
			if t.log != nil {
				t.log.Errorf("file write failed path=%s err=%v", resolved, err)
			}
			return "", err
		}
		if t.log != nil {
			t.log.Infof("file write success path=%s bytes=%d", resolved, len(parts[1]))
		}
		return "ok", nil
	}

	return "", fmt.Errorf("unsupported file command")
}

func (t *Tool) resolveAllowed(path string) (string, error) {
	abs, err := filepath.Abs(path)
	if err != nil {
		return "", err
	}
	abs = filepath.Clean(abs)
	for _, allowed := range t.allowedDirs {
		if strings.HasPrefix(abs, allowed+string(filepath.Separator)) || abs == allowed {
			return abs, nil
		}
	}
	return "", fmt.Errorf("path not allowed: %s", path)
}