from __future__ import annotations

import sys

from dataclasses import dataclass
from pathlib    import Path

from src.paths       import get_layouts_dir
from src.result_types import ErrorInfo, ErrorKind, Result


@dataclass(frozen=True, slots=True)
class LayoutFile:
 """A bundled Manual Slop layout asset (.ini). Stores raw INI text
 intended to be installed to cwd/manualslop_layout.ini by App._post_init
 when the user's INI is empty or missing. The raw text is opaque to
 this module; structure parsing (ImGui sections, [Window] entries)
 is the consumer's responsibility.
 [C: src/layouts.py:load_layouts_from_dir, src/gui_2.py:_install_default_layout_if_empty]"""
 name:        str
 raw_text:    str
 source_path: Path
 scope:       str


def load_layouts_from_file(path: Path, scope: str) -> dict[str, LayoutFile]:
 """Load ONE layout file and return a 1-entry dict. Public API matches
 themes' load_themes_from_toml shape (dict out).
 [C: src/layouts.py:load_layouts_from_dir]"""
 out: dict[str, LayoutFile] = {}
 if not path.exists() or not path.is_file():
  return out
 try:
  raw = path.read_text(encoding="utf-8", errors="replace")
 except OSError as e:
  _layout_err = Result(data=None, errors=[ErrorInfo(kind=ErrorKind.INVALID_INPUT, message=f"failed to read layout {path}: {e}", source="layouts.load_layouts_from_file", original=e)])
  print(f"warning: failed to read {path}: {e}", file=sys.stderr)
  return out
 out[path.stem] = LayoutFile(name=path.stem, raw_text=raw, source_path=path, scope=scope)
 return out


def load_layouts_from_dir(path: Path, scope: str) -> dict[str, LayoutFile]:
 """Load every .ini layout in `path`. Empty dict on missing dir
 or all-skip (per the 'delete to turn off' pattern in
 conductor/code_styleguides/feature_flags.md). Per-file errors are
 drained via Result + stderr warn, mirroring
 src/theme_models.py:load_themes_from_dir.
 [C: src/layouts.py:load_layouts_from_disk]"""
 out: dict[str, LayoutFile] = {}
 if not path.exists() or not path.is_dir():
  return out
 for child in sorted(path.iterdir()):
  if not child.is_file():
   continue
  if child.suffix.lower() != ".ini":
   continue
  try:
   raw = child.read_text(encoding="utf-8", errors="replace")
  except OSError as e:
   _layout_err = Result(data=None, errors=[ErrorInfo(kind=ErrorKind.INVALID_INPUT, message=f"failed to read layout {child}: {e}", source="layouts.load_layouts_from_dir", original=e)])
   print(f"warning: failed to read {child}: {e}", file=sys.stderr)
   continue
  layout = LayoutFile(name=child.stem, raw_text=raw, source_path=child, scope=scope)
  out[layout.name] = layout
 return out


_LAYOUTS_CACHE: dict[str, LayoutFile] = {}


def load_layouts_from_disk() -> dict[str, LayoutFile]:
 """Load all bundled layouts from the global layouts dir
 (resolved via src/paths.py:get_layouts_dir()). Cached at the
 module level; callers iterate the returned dict. The 'delete to
 turn off' guarantee: a missing or empty layouts/ dir returns {}.
 [C: src/gui_2.py:_install_default_layout_if_empty]"""
 global _LAYOUTS_CACHE
 layouts_dir = get_layouts_dir()
 _LAYOUTS_CACHE = load_layouts_from_dir(layouts_dir, scope="global")
 return _LAYOUTS_CACHE