"""The program catalog: the Programs/ folder (manifests, templates, icons),
fetched from the SaraSuite repo itself, so adding a program or fixing an
install recipe only takes a push, not a new AppImage.

The latest commit of the SaraSuite repo is checked the same way programs
are (Sources.py). When it changed, its Programs/ folder is downloaded into
~/.cache/SaraSuite/Catalog/. LoadPrograms() then reads that, falling back
to the AppImage's bundled copy when there's no catalog yet, when it can't be
loaded, or when running from source: there, the local Programs/ folder
always wins, so unpushed manifest edits work while developing.
"""

import shutil
from pathlib import Path
from typing import Callable, Optional

from Core import BundledManifestsDir, CacheHome, IsFrozen, LoadConfig
from Sources import ClearDownloads, Download, LatestCommit, SourceError

CatalogDir = CacheHome / "SaraSuite" / "Catalog"
_CommitFile = CatalogDir / "Commit"
_DownloadName = "SaraSuiteCatalog"


def ManifestsDir() -> Path:
    if IsFrozen and (CatalogDir / "Programs").is_dir():
        return CatalogDir / "Programs"
    return BundledManifestsDir


def CatalogCommit() -> str:
    return _CommitFile.read_text().strip() if _CommitFile.is_file() else ""


def UpdateCatalog(Log: Optional[Callable[[str], None]] = None) -> bool:
    """Fetch the SaraSuite repo's Programs/ if it has a new commit. Returns
    True when the catalog changed (the program list should be reloaded).
    Does nothing when running from source, and quietly keeps the current
    catalog when the git host can't be reached."""
    if not IsFrozen:
        return False
    Log = Log or (lambda Line: None)
    Url = f"{LoadConfig().GitHost.rstrip('/')}/SaraSuite"
    try:
        Commit = LatestCommit(Url)
    except SourceError:
        return False
    if Commit == CatalogCommit():
        return False

    try:
        Source = Download(_DownloadName, Url, Commit, Log) / "Programs"
        if not Source.is_dir():
            return False
        Staging = CatalogDir.with_name("Catalog.new")
        shutil.rmtree(Staging, ignore_errors=True)
        shutil.copytree(Source, Staging / "Programs", ignore=shutil.ignore_patterns("__pycache__"))
        (Staging / "Commit").write_text(Commit)
        shutil.rmtree(CatalogDir, ignore_errors=True)
        Staging.rename(CatalogDir)
    except (SourceError, OSError) as Error:
        Log(f"Couldn't update the program list: {Error}")
        return False
    finally:
        ClearDownloads(_DownloadName)
    Log(f"Program list updated to SaraSuite commit {Commit[:7]}")
    return True