from __future__ import annotations

import gzip

import numpy as np
import pytest
from hypothesis import given
from hypothesis import strategies as st

from simurg.core.errors import FormatError
from simurg.formats.binutil import BinaryReader, BinaryWriter, load_bytes


@given(st.text(max_size=400))
def test_string_roundtrip(s: str) -> None:
    w = BinaryWriter()
    w.string(s)
    r = BinaryReader(w.getvalue(), "E_GTC_CORRUPT")
    assert r.string() == s
    assert r.remaining() == 0


@pytest.mark.parametrize("n", [0, 1, 127, 128, 16383, 16384, 300_000])
def test_varint_boundaries(n: int) -> None:
    w = BinaryWriter()
    w.string(b"x" * n)
    r = BinaryReader(w.getvalue(), "E_GTC_CORRUPT")
    assert r.varint_length() == n


def test_invalid_utf8_is_replaced_not_raised() -> None:  # IN-033, EDGE-002
    w = BinaryWriter()
    w.string(b"ok\xff\xfe")
    assert BinaryReader(w.getvalue(), "E_GTC_CORRUPT").string() == "ok��"


def test_string_past_eof_is_format_error() -> None:
    buf = bytes([50]) + b"short"
    with pytest.raises(FormatError) as e:
        BinaryReader(buf, "E_GTC_CORRUPT", "x.gtc").string()
    assert e.value.code == "E_GTC_CORRUPT"


def test_bad_varint_is_format_error() -> None:
    with pytest.raises(FormatError):
        BinaryReader(b"\xff\xff\xff\xff\xff\xff", "E_BPM_FORMAT").varint_length()


def test_array_bounds_and_seek() -> None:
    r = BinaryReader(np.arange(4, dtype="<i4").tobytes(), "E_IDAT_FORMAT")
    assert r.array("<i4", 4).tolist() == [0, 1, 2, 3]
    r.seek(0)
    with pytest.raises(FormatError):
        r.array("<i4", 5)
    with pytest.raises(FormatError):
        r.seek(100)


def test_load_bytes_gzip(tmp_path) -> None:  # type: ignore[no-untyped-def]
    p = tmp_path / "a.bin.gz"
    p.write_bytes(gzip.compress(b"hello"))
    assert bytes(load_bytes(p)) == b"hello"
    q = tmp_path / "b.bin"
    q.write_bytes(b"world")
    assert bytes(load_bytes(q)) == b"world"
    e = tmp_path / "empty.bin"
    e.write_bytes(b"")
    assert bytes(load_bytes(e)) == b""