package admin

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

// resolveDataPath resolves a request-supplied path inside the admin data
// directory, rejecting paths that would escape it via .. segments. The
// returned path is always filepath.Join(dataDir, cleaned relative path).
func resolveDataPath(dataDir, relPath string) (string, error) {
	clean := filepath.Clean(strings.TrimPrefix(strings.TrimPrefix(relPath, "/"), "data/"))
	if clean == ".." || strings.HasPrefix(clean, ".."+string(filepath.Separator)) {
		return "", fmt.Errorf("path escapes the data directory: %s", relPath)
	}
	return filepath.Join(dataDir, clean), nil
}

// evictDeletedRoomFile drops cached room state and any cached in-room games
// when the raw file manager deletes a room YAML (rooms/<dir>/<id>.yaml).
// Best-effort: only numeric .yaml stems under rooms/ count as room files.
func (s *AdminServer) evictDeletedRoomFile(relPath string) {
	dir, base := filepath.Split(relPath)
	idStr, ok := strings.CutSuffix(base, ".yaml")
	if !ok || idStr == "" {
		return
	}
	dir = strings.TrimSuffix(dir, "/")
	if dir == "rooms" || strings.HasPrefix(dir, "rooms"+string(filepath.Separator)) {
		id, err := strconv.Atoi(idStr)
		if err != nil {
			return
		}
		s.world.RebuildRoomIndex(s.dataDir)
		s.world.ClearRoomState(id)
		if s.mobStore != nil {
			s.mobStore.RemoveMobsInRoom(id)
		}
		if s.evictRoom != nil {
			s.evictRoom(id)
		}
	}
}

func (s *AdminServer) handleFileRename(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	var body struct {
		Path    string `json:"path"`
		NewName string `json:"new_name"`
	}
	if err := readJSON(r, &body); err != nil || body.Path == "" || body.NewName == "" {
		failJSON(w, "missing path or new_name")
		return
	}

	newName := strings.TrimSpace(body.NewName)
	if newName == "" || newName == "." || newName == ".." || strings.ContainsAny(newName, "/\\") {
		failJSON(w, "invalid file name")
		return
	}
	for _, c := range newName {
		if c < 32 || c == 127 {
			failJSON(w, "file name contains invalid characters")
			return
		}
	}

	relPath := strings.TrimPrefix(body.Path, "/")
	relPath = strings.TrimPrefix(relPath, "data/")
	oldAbs, err := resolveDataPath(s.dataDir, relPath)
	if err != nil {
		failJSON(w, err.Error())
		return
	}

	oldContent, err := snapshotFile(oldAbs)
	if err != nil {
		failJSON(w, "file not found: "+relPath)
		return
	}

	newAbs := filepath.Join(filepath.Dir(oldAbs), newName)
	if _, err := os.Stat(newAbs); err == nil {
		failJSON(w, "a file named "+newName+" already exists")
		return
	}

	if err := os.WriteFile(newAbs, oldContent, 0644); err != nil {
		failJSON(w, "write error: "+err.Error())
		return
	}
	if err := os.Remove(oldAbs); err != nil {
		failJSON(w, "remove error: "+err.Error())
		return
	}

	newRelPath := filepath.Join(filepath.Dir(relPath), newName)
	if filepath.Dir(relPath) == "." {
		newRelPath = newName
	}
	s.undoStack.Push(ChangeDesc{
		Description: "Renamed file " + relPath + " to " + newRelPath,
		FilePath:    oldAbs,
		NewFilePath: newAbs,
		OldContent:  oldContent,
		NewContent:  oldContent,
	})
	writeJSON(w, map[string]any{"ok": true, "path": newRelPath})
}

func (s *AdminServer) handleFiles(w http.ResponseWriter, r *http.Request) {
	relPath := r.URL.Query().Get("path")
	relPath = strings.TrimPrefix(relPath, "/")
	relPath = strings.TrimPrefix(relPath, "data/")
	fullPath, pathErr := resolveDataPath(s.dataDir, relPath)
	if pathErr != nil {
		failJSON(w, pathErr.Error())
		return
	}

	switch r.Method {
	case http.MethodGet:
		if relPath == "" {
			entries, err := os.ReadDir(fullPath)
			if err != nil {
				failJSON(w, err.Error())
				return
			}
			var files []map[string]any
			for _, e := range entries {
				files = append(files, map[string]any{
					"name": e.Name(),
					"dir":  e.IsDir(),
				})
			}
			writeJSON(w, files)
			return
		}

		fullPath := filepath.Join(s.dataDir, relPath)
		info, err := os.Stat(fullPath)
		if err != nil {
			failJSON(w, "not found: "+relPath)
			return
		}

		if info.IsDir() {
			entries, err := os.ReadDir(fullPath)
			if err != nil {
				failJSON(w, err.Error())
				return
			}
			var files []map[string]any
			for _, e := range entries {
				files = append(files, map[string]any{
					"name": e.Name(),
					"dir":  e.IsDir(),
				})
			}
			writeJSON(w, files)
			return
		}

		data, err := os.ReadFile(fullPath)
		if err != nil {
			failJSON(w, "read error: "+err.Error())
			return
		}
		writeJSON(w, map[string]any{
			"name":    info.Name(),
			"content": string(data),
			"path":    relPath,
		})

	case http.MethodPut, http.MethodPost:
		if relPath == "" {
			failJSON(w, "missing path")
			return
		}
		body, err := io.ReadAll(r.Body)
		if err != nil {
			failJSON(w, "read body: "+err.Error())
			return
		}

		var oldContent []byte
		if existing, err := snapshotFile(fullPath); err == nil {
			oldContent = existing
		}

		dir := filepath.Dir(fullPath)
		if err := os.MkdirAll(dir, 0755); err != nil {
			failJSON(w, "mkdir: "+err.Error())
			return
		}

		if err := os.WriteFile(fullPath, body, 0644); err != nil {
			failJSON(w, "write error: "+err.Error())
			return
		}

		isCreate := oldContent == nil
		desc := "Updated file " + relPath
		if isCreate {
			desc = "Created file " + relPath
		}
		s.undoStack.Push(ChangeDesc{
			Description: desc,
			FilePath:    fullPath,
			OldContent:  oldContent,
			NewContent:  body,
			IsCreate:    isCreate,
		})
		writeJSON(w, map[string]any{"ok": true, "path": relPath})

	case http.MethodDelete:
		if relPath == "" {
			failJSON(w, "missing path")
			return
		}
		oldContent, _ := snapshotFile(fullPath)
		if err := os.Remove(fullPath); err != nil {
			failJSON(w, "delete error: "+err.Error())
			return
		}
		s.evictDeletedRoomFile(relPath)
		s.undoStack.Push(ChangeDesc{
			Description: "Deleted file " + relPath,
			FilePath:    fullPath,
			OldContent:  oldContent,
			IsDelete:    true,
		})
		writeJSON(w, map[string]any{"ok": true, "path": relPath})

	default:
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
	}
}