"""Pure-helper tests for l4d2web.services.overlay_files.

Covers path safety (listing vs download), directory listing semantics,
symlink handling, and the children cap. Flask-free; only exercises the
filesystem.
"""
from __future__ import annotations

import os
from pathlib import Path

import pytest


@pytest.fixture
def overlay_root(monkeypatch, tmp_path: Path) -> Path:
    """LEFT4ME_ROOT/overlays/7/ ready for tests to populate. Returns the overlay root."""
    monkeypatch.setenv("LEFT4ME_ROOT", str(tmp_path))
    root = tmp_path / "overlays" / "7"
    root.mkdir(parents=True)
    return root


def test_safe_resolve_for_listing_returns_overlay_root_when_sub_path_empty(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_listing

    resolved = safe_resolve_for_listing("7", "")

    assert resolved == overlay_root.resolve()


def test_safe_resolve_for_listing_joins_sub_path_under_overlay_root(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_listing

    (overlay_root / "left4dead2" / "addons").mkdir(parents=True)

    resolved = safe_resolve_for_listing("7", "left4dead2/addons")

    assert resolved == (overlay_root / "left4dead2" / "addons").resolve()


def test_safe_resolve_for_listing_rejects_dotdot(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_listing

    with pytest.raises(ValueError):
        safe_resolve_for_listing("7", "../../etc")


def test_safe_resolve_for_listing_rejects_absolute_path(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_listing

    with pytest.raises(ValueError):
        safe_resolve_for_listing("7", "/etc/passwd")


def test_safe_resolve_for_listing_rejects_empty_component(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_listing

    with pytest.raises(ValueError):
        safe_resolve_for_listing("7", "foo//bar")


def test_safe_resolve_for_listing_rejects_symlink_escaping_overlay_root(
    overlay_root: Path, tmp_path: Path
) -> None:
    """A directory inside the overlay that is itself a symlink to somewhere
    outside the overlay must be refused — even if the target sits within
    LEFT4ME_ROOT/workshop_cache."""
    from l4d2web.services.overlay_files import safe_resolve_for_listing

    cache = tmp_path / "workshop_cache" / "shared"
    cache.mkdir(parents=True)
    (overlay_root / "shared").symlink_to(cache)

    with pytest.raises(ValueError):
        safe_resolve_for_listing("7", "shared")


def test_safe_resolve_for_download_rejects_empty_path(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_download

    with pytest.raises(ValueError):
        safe_resolve_for_download("7", "")


def test_safe_resolve_for_download_returns_real_path_for_regular_file(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_download

    target = overlay_root / "cfg" / "server.cfg"
    target.parent.mkdir()
    target.write_text("hostname test\n")

    resolved = safe_resolve_for_download("7", "cfg/server.cfg")

    assert resolved == target.resolve()


def test_safe_resolve_for_download_follows_symlink_into_workshop_cache(
    overlay_root: Path, tmp_path: Path
) -> None:
    """Workshop overlays populate addons/*.vpk as symlinks into
    LEFT4ME_ROOT/workshop_cache/. Download must follow the symlink and
    return the cache target."""
    from l4d2web.services.overlay_files import safe_resolve_for_download

    cache_file = tmp_path / "workshop_cache" / "12345.vpk"
    cache_file.parent.mkdir(parents=True)
    cache_file.write_bytes(b"vpk-bytes")

    addons = overlay_root / "left4dead2" / "addons"
    addons.mkdir(parents=True)
    (addons / "deathcraft.vpk").symlink_to(cache_file)

    resolved = safe_resolve_for_download("7", "left4dead2/addons/deathcraft.vpk")

    assert resolved == cache_file.resolve()


def test_safe_resolve_for_download_rejects_symlink_outside_left4me_root(
    overlay_root: Path, tmp_path: Path
) -> None:
    """A malicious script overlay that plants a symlink at evil → /etc/passwd
    must be refused."""
    from l4d2web.services.overlay_files import safe_resolve_for_download

    outside = tmp_path.parent / "outside-left4me-root.txt"
    outside.write_text("nope")
    (overlay_root / "evil").symlink_to(outside)

    with pytest.raises(ValueError):
        safe_resolve_for_download("7", "evil")


def test_safe_resolve_for_download_rejects_dotdot(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_download

    with pytest.raises(ValueError):
        safe_resolve_for_download("7", "../../etc/passwd")


def test_safe_resolve_for_download_rejects_absolute_path(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_download

    with pytest.raises(ValueError):
        safe_resolve_for_download("7", "/etc/passwd")


def test_list_directory_returns_empty_for_empty_dir(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    entries, truncated = list_directory(overlay_root, overlay_root)

    assert entries == []
    assert truncated == 0


def test_list_directory_returns_dirs_before_files_alphabetically(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import list_directory

    (overlay_root / "Zeta").mkdir()
    (overlay_root / "alpha").mkdir()
    (overlay_root / "Beta-file.txt").write_text("b")
    (overlay_root / "alpha-file.txt").write_text("a")

    entries, _ = list_directory(overlay_root, overlay_root)
    names = [e["name"] for e in entries]

    # Dirs first (case-insensitive alpha), then files (case-insensitive alpha).
    assert names == ["alpha", "Zeta", "alpha-file.txt", "Beta-file.txt"]


def test_list_directory_marks_kind_dir_or_file(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    (overlay_root / "subdir").mkdir()
    (overlay_root / "leaf.txt").write_text("hi")

    entries, _ = list_directory(overlay_root, overlay_root)
    by_name = {e["name"]: e for e in entries}

    assert by_name["subdir"]["kind"] == "dir"
    assert by_name["leaf.txt"]["kind"] == "file"


def test_list_directory_includes_relative_path_under_overlay_root(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import list_directory

    addons = overlay_root / "left4dead2" / "addons"
    addons.mkdir(parents=True)
    (addons / "foo.vpk").write_text("v")

    entries, _ = list_directory(addons, overlay_root)

    assert entries[0]["rel"] == "left4dead2/addons/foo.vpk"


def test_list_directory_marks_symlinks_with_resolved_size(
    overlay_root: Path, tmp_path: Path
) -> None:
    from l4d2web.services.overlay_files import list_directory

    cache_file = tmp_path / "workshop_cache" / "12345.vpk"
    cache_file.parent.mkdir(parents=True)
    cache_file.write_bytes(b"x" * 4096)

    addons = overlay_root / "left4dead2" / "addons"
    addons.mkdir(parents=True)
    (addons / "deathcraft.vpk").symlink_to(cache_file)

    entries, _ = list_directory(addons, overlay_root)
    entry = entries[0]

    assert entry["is_symlink"] is True
    assert entry["broken"] is False
    assert entry["size"] == 4096
    assert entry["kind"] == "file"


def test_list_directory_marks_broken_symlinks(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    (overlay_root / "missing.vpk").symlink_to(overlay_root / "does-not-exist.vpk")

    entries, _ = list_directory(overlay_root, overlay_root)
    entry = entries[0]

    assert entry["is_symlink"] is True
    assert entry["broken"] is True
    assert entry["size"] is None
    assert entry["kind"] == "file"


def test_list_directory_truncates_at_cap(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    for i in range(7):
        (overlay_root / f"f{i:02d}.txt").write_text("x")

    entries, truncated = list_directory(overlay_root, overlay_root, max_entries=5)

    assert len(entries) == 5
    assert truncated == 2
    assert [e["name"] for e in entries] == [f"f{i:02d}.txt" for i in range(5)]


def test_list_directory_includes_size_human_for_files(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    (overlay_root / "tiny.txt").write_text("hello")
    (overlay_root / "big.bin").write_bytes(b"x" * (3 * 1024 * 1024))

    entries, _ = list_directory(overlay_root, overlay_root)
    by_name = {e["name"]: e for e in entries}

    # Files only — directories don't have size_human.
    assert by_name["tiny.txt"]["size_human"] == "5 B"
    assert by_name["big.bin"]["size_human"] == "3.0 MB"


# ---- safe_resolve_for_write -------------------------------------------------


def test_safe_resolve_for_write_returns_path_under_overlay_root(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_write

    resolved = safe_resolve_for_write("7", "left4dead2/cfg/server.cfg")

    assert resolved == overlay_root / "left4dead2" / "cfg" / "server.cfg"


def test_safe_resolve_for_write_rejects_empty_path(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_write

    with pytest.raises(ValueError):
        safe_resolve_for_write("7", "")


def test_safe_resolve_for_write_rejects_dotdot(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_write

    with pytest.raises(ValueError):
        safe_resolve_for_write("7", "../escape.txt")


def test_safe_resolve_for_write_rejects_overwriting_symlink(
    overlay_root: Path, tmp_path: Path
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_write

    target = tmp_path / "outside.txt"
    target.write_text("nope")
    (overlay_root / "evil").symlink_to(target)

    with pytest.raises(ValueError):
        safe_resolve_for_write("7", "evil")


def test_safe_resolve_for_write_rejects_path_with_non_dir_parent(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_write

    (overlay_root / "blocker").write_text("file, not dir")

    with pytest.raises(ValueError):
        safe_resolve_for_write("7", "blocker/child.txt")


# ---- safe_resolve_for_delete -----------------------------------------------


def test_safe_resolve_for_delete_returns_resolvable_path(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_delete

    target = overlay_root / "cfg" / "server.cfg"
    target.parent.mkdir()
    target.write_text("x")

    resolved = safe_resolve_for_delete("7", "cfg/server.cfg")

    assert resolved == target


def test_safe_resolve_for_delete_rejects_dotdot(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_delete

    with pytest.raises(ValueError):
        safe_resolve_for_delete("7", "../neighbour")


def test_safe_resolve_for_delete_rejects_empty(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_delete

    with pytest.raises(ValueError):
        safe_resolve_for_delete("7", "")


def test_safe_resolve_for_delete_rejects_symlink_escaping_root(
    overlay_root: Path, tmp_path: Path
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_delete

    outside = tmp_path / "outside-link.txt"
    outside.write_text("nope")
    (overlay_root / "evil").symlink_to(outside)

    with pytest.raises(ValueError):
        safe_resolve_for_delete("7", "evil")


# ---- safe_resolve_for_move -------------------------------------------------


def test_safe_resolve_for_move_returns_paths_when_valid(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_move

    src = overlay_root / "motd.txt"
    src.write_text("welcome")
    (overlay_root / "addons").mkdir()

    src_path, dst_path = safe_resolve_for_move("7", "motd.txt", "addons/motd.txt")

    assert src_path == src
    assert dst_path == overlay_root / "addons" / "motd.txt"


def test_safe_resolve_for_move_rejects_missing_src(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_move

    with pytest.raises(ValueError):
        safe_resolve_for_move("7", "nope.txt", "addons/nope.txt")


def test_safe_resolve_for_move_rejects_dst_parent_not_directory(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_move

    (overlay_root / "src.txt").write_text("x")
    (overlay_root / "blocker").write_text("file, not dir")

    with pytest.raises(ValueError):
        safe_resolve_for_move("7", "src.txt", "blocker/dst.txt")


def test_safe_resolve_for_move_rejects_dst_inside_src(overlay_root: Path) -> None:
    """Moving a directory into itself or a descendant must fail before any
    rename happens."""
    from l4d2web.services.overlay_files import safe_resolve_for_move

    src = overlay_root / "addons"
    src.mkdir()
    (src / "child").mkdir()

    with pytest.raises(ValueError):
        safe_resolve_for_move("7", "addons", "addons/child/addons")


def test_safe_resolve_for_move_rejects_overwrite_of_symlink(
    overlay_root: Path, tmp_path: Path
) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_move

    (overlay_root / "src.txt").write_text("x")
    (overlay_root / "dst").symlink_to(tmp_path / "outside.txt")

    with pytest.raises(ValueError):
        safe_resolve_for_move("7", "src.txt", "dst")


def test_safe_resolve_for_move_rejects_dotdot(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import safe_resolve_for_move

    (overlay_root / "src.txt").write_text("x")

    with pytest.raises(ValueError):
        safe_resolve_for_move("7", "src.txt", "../escape.txt")


# ---- is_editable -----------------------------------------------------------


def test_is_editable_true_for_small_utf8_file(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import is_editable

    target = overlay_root / "motd.txt"
    target.write_text("Welcome\nHave fun.\n")

    assert is_editable(target) is True


def test_is_editable_false_for_oversized_file(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import is_editable

    target = overlay_root / "huge.bin"
    # 1 MiB + 1 byte
    target.write_bytes(b"a" * (1024 * 1024 + 1))

    assert is_editable(target) is False


def test_is_editable_false_for_binary_content_in_first_8kib(
    overlay_root: Path,
) -> None:
    from l4d2web.services.overlay_files import is_editable

    target = overlay_root / "fake.vpk"
    # Random binary bytes in the sniff window — should fail strict UTF-8.
    target.write_bytes(bytes(range(256)) * 40)

    assert is_editable(target) is False


def test_is_editable_false_for_symlink(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import is_editable

    real = overlay_root / "real.txt"
    real.write_text("hi")
    link = overlay_root / "link.txt"
    link.symlink_to(real)

    assert is_editable(link) is False


def test_is_editable_false_for_directory(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import is_editable

    sub = overlay_root / "subdir"
    sub.mkdir()

    assert is_editable(sub) is False


def test_entry_dict_marks_editable_for_small_utf8_file(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    (overlay_root / "small.txt").write_text("hello")
    (overlay_root / "big.bin").write_bytes(b"\x00" * 200)

    entries, _ = list_directory(overlay_root, overlay_root)
    by_name = {e["name"]: e for e in entries}

    assert by_name["small.txt"]["editable"] is True
    assert by_name["big.bin"]["editable"] is False


def test_entry_dict_marks_directories_not_editable(overlay_root: Path) -> None:
    from l4d2web.services.overlay_files import list_directory

    (overlay_root / "subdir").mkdir()

    entries, _ = list_directory(overlay_root, overlay_root)
    by_name = {e["name"]: e for e in entries}

    assert by_name["subdir"]["editable"] is False