project_repo.py

"""Project repository: single entry point for load/save/autosave with dirty tracking."""

from __future__ import annotations

import logging
import os
from pathlib import Path
from typing import Callable, Optional

from PyQt6.QtCore import QTimer, pyqtSignal, QObject

from model import Project, create_lyrics_block
from storage import detect_storage

_LOGGER = logging.getLogger(__name__)


def _user_data_root() -> Path:
    target = Path(__file__).parent / "user_data"
    target.mkdir(parents=True, exist_ok=True)
    return target


class ProjectRepo(QObject):
    """Manages project persistence, dirty tracking, and autosave."""

    projectChanged = pyqtSignal()
    modifiedChanged = pyqtSignal(bool)

    def __init__(self, parent: Optional[QObject] = None) -> None:
        super().__init__(parent)
        self._project: Project = Project.new_default()
        self._path: Optional[str] = None
        self._modified: bool = False
        self._snapshots: list[Project] = []

        # Autosave debounce timer
        self._autosave_timer = QTimer(self)
        self._autosave_timer.setSingleShot(True)
        self._autosave_timer.setInterval(500)
        self._autosave_timer.timeout.connect(self._flush_autosave)

    # ── properties ──────────────────────────────────────────────

    @property
    def project(self) -> Project:
        return self._project

    @property
    def path(self) -> Optional[str]:
        return self._path

    @path.setter
    def path(self, value: Optional[str]) -> None:
        self._path = value

    @property
    def is_modified(self) -> bool:
        return self._modified

    # ── load ────────────────────────────────────────────────────

    def load(self, path: str) -> None:
        storage = detect_storage(path)
        self._project = storage.load(path)
        self._path = path
        self._modified = False
        self._snapshots.clear()
        self.projectChanged.emit()

    def load_autosave(self) -> bool:
        autosave_path = _user_data_root() / "autosave.rapnote"
        if not autosave_path.exists():
            return False
        try:
            self.load(str(autosave_path))
            self._path = None  # autosave has no user path
            self._modified = False
            return True
        except Exception as exc:
            _LOGGER.warning("Failed to load autosave: %s", exc)
            return False

    # ── save ────────────────────────────────────────────────────

    def save(self, path: Optional[str] = None) -> bool:
        target = path or self._path
        if not target:
            return False
        try:
            storage = detect_storage(target)
            storage.save(self._project, target)
            self._path = target
            self._modified = False
            self.modifiedChanged.emit(False)
            return True
        except Exception as exc:
            _LOGGER.error("Save failed: %s", exc)
            return False

    def save_autosave(self) -> None:
        autosave_path = str(_user_data_root() / "autosave.rapnote")
        try:
            storage = detect_storage(autosave_path)
            storage.save(self._project, autosave_path)
        except Exception as exc:
            _LOGGER.error("Autosave failed: %s", exc)

    def delete_autosave(self) -> None:
        autosave_path = _user_data_root() / "autosave.rapnote"
        try:
            autosave_path.unlink(missing_ok=True)
        except Exception:
            pass

    # ── mutation tracking ───────────────────────────────────────

    def mark_modified(self) -> None:
        if not self._modified:
            self._snapshot()
        self._modified = True
        self.modifiedChanged.emit(True)
        if not self._autosave_timer.isActive():
            self._autosave_timer.start()

    def set_project(self, project: Project, path: Optional[str] = None) -> None:
        self._snapshot()
        self._project = project
        if path is not None:
            self._path = path
        self._modified = True
        self.modifiedChanged.emit(True)
        self.projectChanged.emit()

    def new_project(self) -> None:
        self._snapshot()
        self._project = Project.new_default()
        self._path = None
        self._modified = False
        self.modifiedChanged.emit(False)
        self.projectChanged.emit()

    # ── undo (snapshot stack) ───────────────────────────────────

    def _snapshot(self) -> None:
        self._snapshots.append(self._clone_project())
        if len(self._snapshots) > 20:
            self._snapshots.pop(0)

    def can_undo(self) -> bool:
        return len(self._snapshots) > 0

    def undo(self) -> bool:
        if not self._snapshots:
            return False
        self._project = self._snapshots.pop()
        self._modified = bool(self._snapshots)
        self.modifiedChanged.emit(self._modified)
        self.projectChanged.emit()
        return True

    def _clone_project(self) -> Project:
        import copy
        return copy.deepcopy(self._project)

    # ── autosave ────────────────────────────────────────────────

    def _flush_autosave(self) -> None:
        if self._modified:
            self.save_autosave()