"""Tests for piece management — TDD: tests before implementation."""

import pytest
from i2p_apps.snark.pieces import PieceManager, PieceState


class TestPieceManager:
    def test_creation(self):
        pm = PieceManager(total_pieces=10, piece_length=16384, total_size=163840)
        assert pm.total_pieces == 10
        assert pm.completed_count == 0

    def test_initial_state(self):
        pm = PieceManager(total_pieces=5, piece_length=16384, total_size=81920)
        for i in range(5):
            assert pm.state(i) == PieceState.MISSING

    def test_mark_complete(self):
        pm = PieceManager(total_pieces=5, piece_length=16384, total_size=81920)
        pm.mark_complete(0)
        assert pm.state(0) == PieceState.COMPLETE
        assert pm.completed_count == 1

    def test_mark_requested(self):
        pm = PieceManager(total_pieces=5, piece_length=16384, total_size=81920)
        pm.mark_requested(2)
        assert pm.state(2) == PieceState.REQUESTED

    def test_next_needed(self):
        pm = PieceManager(total_pieces=3, piece_length=16384, total_size=49152)
        pm.mark_complete(0)
        available = {0, 1, 2}
        needed = pm.next_needed(available)
        assert needed is not None
        assert needed != 0  # Already complete

    def test_next_needed_none(self):
        pm = PieceManager(total_pieces=2, piece_length=16384, total_size=32768)
        pm.mark_complete(0)
        pm.mark_complete(1)
        assert pm.next_needed({0, 1}) is None

    def test_is_complete(self):
        pm = PieceManager(total_pieces=2, piece_length=16384, total_size=32768)
        assert pm.is_complete is False
        pm.mark_complete(0)
        pm.mark_complete(1)
        assert pm.is_complete is True

    def test_bitfield(self):
        pm = PieceManager(total_pieces=8, piece_length=16384, total_size=131072)
        pm.mark_complete(0)
        pm.mark_complete(3)
        pm.mark_complete(7)
        bf = pm.bitfield()
        assert len(bf) == 1  # 8 pieces = 1 byte
        assert bf[0] & 0x80  # bit 0
        assert bf[0] & 0x10  # bit 3
        assert bf[0] & 0x01  # bit 7

    def test_percent_complete(self):
        pm = PieceManager(total_pieces=4, piece_length=16384, total_size=65536)
        pm.mark_complete(0)
        pm.mark_complete(1)
        assert pm.percent_complete == 50.0