# Copyright (c) 2026 Krzysztof Rudnicki. MIT licence.
"""Importing a folder: the two-stage dedup, and the arithmetic that proves it."""

from __future__ import annotations

from typing import TYPE_CHECKING

from signal_bot import pack_ledger
from signal_bot.media_sniff import MediaKind
from signal_bot.pack import MEDIA_DIR
from signal_bot.pack_custom import FILE_MODE
from signal_bot.pack_import import plan_import, run_import
from signal_bot.pack_report import SKIPPED_DIR, Outcome
from tests.pack_fixture import CLIP, PIXEL

if TYPE_CHECKING:
    from pathlib import Path

# A second distinct PNG, so a test can have two files that are genuinely
# different rather than two names for one.
OTHER = PIXEL.replace(b"IDAT", b"IDAT", 1) + b"\x00"


class FakeStripper:
    """Strips by mapping bytes, so no test ever shells out to exiftool."""

    def __init__(self, mapping: dict[bytes, bytes | None] | None = None) -> None:
        self.mapping = mapping or {}

    def strip(self, payload: bytes, kind: MediaKind) -> bytes | None:
        """The mapped output, or the payload unchanged."""
        assert isinstance(kind, MediaKind)
        return self.mapping.get(payload, payload)


def _album(tmp_path: Path, files: dict[str, bytes] | None = None) -> Path:
    directory = tmp_path / "pack"
    media = directory / MEDIA_DIR
    media.mkdir(parents=True)
    for name, payload in (files or {}).items():
        (media / name).write_bytes(payload)
    return directory


def _source(tmp_path: Path, files: dict[str, bytes]) -> Path:
    source = tmp_path / "batch" / "Folder"
    source.mkdir(parents=True)
    for name, payload in files.items():
        (source / name).write_bytes(payload)
    return source


def test_every_file_lands_in_exactly_one_bucket(tmp_path: Path) -> None:
    # The done condition, mechanised: the buckets must sum to what was seen.
    directory = _album(tmp_path, {"have.png": PIXEL})
    source = _source(
        tmp_path,
        {"new.png": OTHER, "same.png": PIXEL, "copy.png": OTHER, "notes.txt": b"hello"},
    )
    report = plan_import(source, directory, FakeStripper())
    assert sum(report.counts.values()) == len(report.decisions) == 4
    assert report.counts == {
        Outcome.NOT_MEDIA: 1,
        Outcome.UNSTRIPPABLE: 0,
        Outcome.ALREADY_IN_PACK: 1,
        Outcome.EXACT_DUP: 1,
        Outcome.IMPORTED: 1,
    }
    assert report.before == 1
    assert report.after == 2


def test_the_report_prints_every_bucket_including_the_empty_ones(tmp_path: Path) -> None:
    # A suppressed zero is a silently missing category; "0 could not be
    # stripped" is how the operator sees the video fix still holding.
    report = plan_import(_source(tmp_path, {}), _album(tmp_path), FakeStripper())
    body = "\n".join(report.lines())
    for outcome in Outcome:
        assert str(outcome) in body or outcome is Outcome.IMPORTED
    assert "could not be stripped" in body
    assert "accounted for" in body


def test_a_file_already_in_the_album_is_not_imported_twice(tmp_path: Path) -> None:
    directory = _album(tmp_path, {"have.png": PIXEL})
    source = _source(tmp_path, {"renamed.png": PIXEL})
    report = plan_import(source, directory, FakeStripper())
    assert report.decisions[0].outcome is Outcome.ALREADY_IN_PACK


def test_two_sources_that_strip_to_one_photo_collapse(tmp_path: Path) -> None:
    # The measured case that a source-hash-only ledger would import twice:
    # the same photo re-encoded, identical once the metadata is gone.
    directory = _album(tmp_path)
    source = _source(tmp_path, {"a.png": PIXEL, "b.png": OTHER})
    stripper = FakeStripper({PIXEL: PIXEL, OTHER: PIXEL})
    report = plan_import(source, directory, stripper)
    outcomes = [d.outcome for d in report.decisions]
    assert outcomes == [Outcome.IMPORTED, Outcome.EXACT_DUP]


def test_a_chat_upload_and_an_exported_copy_collapse(tmp_path: Path) -> None:
    # Same as above but across runs: the album already holds the stripped
    # bytes, and the export folder holds the unstripped original.
    directory = _album(tmp_path, {"hash.png": PIXEL})
    source = _source(tmp_path, {"original.png": OTHER})
    report = plan_import(source, directory, FakeStripper({OTHER: PIXEL}))
    assert report.decisions[0].outcome is Outcome.ALREADY_IN_PACK


def test_a_file_the_stripper_will_not_vouch_for_is_refused(tmp_path: Path) -> None:
    report = plan_import(
        _source(tmp_path, {"a.png": PIXEL}), _album(tmp_path), FakeStripper({PIXEL: None})
    )
    assert report.decisions[0].outcome is Outcome.UNSTRIPPABLE


def test_format_is_decided_by_bytes_not_by_suffix(tmp_path: Path) -> None:
    directory = _album(tmp_path)
    source = _source(tmp_path, {"photo.txt": PIXEL, "fake.jpg": b"not an image at all"})
    report = plan_import(source, directory, FakeStripper())
    by_name = {d.source.name: d for d in report.decisions}
    assert by_name["fake.jpg"].outcome is Outcome.NOT_MEDIA
    imported = by_name["photo.txt"]
    assert imported.outcome is Outcome.IMPORTED
    # The suffix is corrected to match the bytes: pack.media_type looks the
    # stored suffix up in a closed table, and a miss fails the *next* load.
    assert imported.stored is not None
    assert imported.stored.name == "photo.png"


def test_a_suffix_that_agrees_with_the_bytes_is_kept(tmp_path: Path) -> None:
    # .jpeg and .jpg are both image/jpeg, so a .jpeg keeps its name.
    jpeg = b"\xff\xd8\xff" + b"\x00" * 40
    source = _source(tmp_path, {"photo.jpeg": jpeg})
    report = plan_import(source, _album(tmp_path), FakeStripper())
    assert report.decisions[0].stored is not None
    assert report.decisions[0].stored.name == "photo.jpeg"


def test_a_name_collision_disambiguates_rather_than_dropping_a_photo(tmp_path: Path) -> None:
    # The old bug: two exports both saying IMG_0001.jpg silently lost one.
    directory = _album(tmp_path, {"IMG_1.png": PIXEL})
    source = _source(tmp_path, {"IMG_1.png": OTHER})
    report = plan_import(source, directory, FakeStripper())
    assert report.decisions[0].stored is not None
    assert report.decisions[0].stored.name == "IMG_1-2.png"


def test_video_is_imported_like_anything_else(tmp_path: Path) -> None:
    report = plan_import(_source(tmp_path, {"c.mp4": CLIP}), _album(tmp_path), FakeStripper())
    assert report.decisions[0].outcome is Outcome.IMPORTED


def test_a_subdirectory_in_the_source_is_ignored(tmp_path: Path) -> None:
    source = _source(tmp_path, {"a.png": PIXEL})
    (source / "nested").mkdir()
    report = plan_import(source, _album(tmp_path), FakeStripper())
    assert len(report.decisions) == 1


def test_running_the_import_stores_the_new_file_and_the_ledger(tmp_path: Path) -> None:
    directory = _album(tmp_path)
    source = _source(tmp_path, {"a.png": PIXEL})
    run_import(source, directory, FakeStripper())
    stored = directory / MEDIA_DIR / "a.png"
    assert stored.read_bytes() == PIXEL
    assert stored.stat().st_mode & 0o777 == FILE_MODE
    assert pack_ledger.read(directory)["a.png"].source == pack_ledger.digest(PIXEL)


def test_a_rejected_file_is_moved_and_never_deleted(tmp_path: Path) -> None:
    directory = _album(tmp_path, {"have.png": PIXEL})
    source = _source(tmp_path, {"same.png": PIXEL, "notes.txt": b"hello"})
    run_import(source, directory, FakeStripper())
    parent = source.parent
    assert (parent / SKIPPED_DIR / "already-in-pack" / "same.png").read_bytes() == PIXEL
    assert (parent / SKIPPED_DIR / "not-media" / "notes.txt").read_bytes() == b"hello"
    assert not (source / "same.png").exists()


def test_the_skipped_folder_sits_beside_the_source_not_under_home(tmp_path: Path) -> None:
    # Derived from the source argument so a tmp_path source keeps every write
    # inside tmp_path -- conftest redirects XDG_DATA_HOME, not $HOME.
    source = _source(tmp_path, {"notes.txt": b"hello"})
    run_import(source, _album(tmp_path), FakeStripper())
    assert (source.parent / SKIPPED_DIR).is_dir()


def test_importing_the_same_folder_twice_is_a_no_op(tmp_path: Path) -> None:
    # The property the ledger exists for.
    directory = _album(tmp_path)
    source = _source(tmp_path, {"a.png": PIXEL})
    run_import(source, directory, FakeStripper())
    again = _source(tmp_path / "second", {"a.png": PIXEL})
    report = run_import(again, directory, FakeStripper())
    assert report.counts[Outcome.IMPORTED] == 0
    assert report.counts[Outcome.ALREADY_IN_PACK] == 1


def test_an_import_creates_the_album_directory_when_there_is_none(tmp_path: Path) -> None:
    directory = tmp_path / "fresh"
    directory.mkdir()
    report = run_import(_source(tmp_path, {"a.png": PIXEL}), directory, FakeStripper())
    assert (directory / MEDIA_DIR / "a.png").exists()
    assert report.before == 0


def test_the_import_does_not_write_tags(tmp_path: Path) -> None:
    # An imported file is simply absent from tags.json, which is what
    # --untagged keys off and what pack_load already tolerates.
    directory = _album(tmp_path)
    run_import(_source(tmp_path, {"a.png": PIXEL}), directory, FakeStripper())
    assert not (directory / "tags.json").exists()


def test_a_photo_that_arrives_mid_run_is_not_stored_twice(tmp_path: Path) -> None:
    # Planning strips every candidate, which takes minutes on a real batch.
    # A photo uploaded from the chat during that window is in the album by
    # the time the apply pass runs, and storing it anyway puts it there
    # twice: once hash-named by !add_photo, once under its original name.
    # Measured: that happened to 6 photos during the first live import.
    directory = _album(tmp_path)
    source = _source(tmp_path, {"a.png": PIXEL})

    class Interloper(FakeStripper):
        """Drops the photo into the album the moment planning reads it."""

        def strip(self, payload: bytes, kind: MediaKind) -> bytes | None:
            (directory / MEDIA_DIR / "from-the-chat.png").write_bytes(payload)
            return super().strip(payload, kind)

    report = run_import(source, directory, Interloper())
    assert report.counts[Outcome.IMPORTED] == 0
    assert report.counts[Outcome.ALREADY_IN_PACK] == 1
    assert sorted(p.name for p in (directory / MEDIA_DIR).iterdir()) == ["from-the-chat.png"]
    # And it is moved aside like any other repeat, never left behind.
    assert (source.parent / SKIPPED_DIR / "already-in-pack" / "a.png").exists()