"""Tests for interrupt handling and race condition fixes.

Validates V-007: Race Condition in Interrupt Propagation fixes.
"""

import threading
import time
import pytest
from tools.interrupt import (
    set_interrupt,
    is_interrupted,
    get_interrupt_count,
    wait_for_interrupt,
    InterruptibleContext,
)


class TestInterruptBasics:
    """Test basic interrupt functionality."""
    
    def test_interrupt_set_and_clear(self):
        """Test basic set/clear cycle."""
        set_interrupt(True)
        assert is_interrupted() is True
        
        set_interrupt(False)
        assert is_interrupted() is False
    
    def test_interrupt_count(self):
        """Test interrupt nesting count."""
        set_interrupt(False)  # Reset
        assert get_interrupt_count() == 0
        
        set_interrupt(True)
        assert get_interrupt_count() == 1
        
        set_interrupt(True)  # Nested
        assert get_interrupt_count() == 2
        
        set_interrupt(False)  # Clear all
        assert get_interrupt_count() == 0
        assert is_interrupted() is False


class TestInterruptRaceConditions:
    """Test race condition fixes (V-007).
    
    These tests validate that the RLock properly synchronizes
    concurrent access to the interrupt state.
    """
    
    def test_concurrent_set_interrupt(self):
        """Test concurrent set operations are thread-safe."""
        set_interrupt(False)  # Reset
        
        results = []
        errors = []
        
        def setter_thread(thread_id):
            try:
                for _ in range(100):
                    set_interrupt(True)
                    time.sleep(0.001)
                    set_interrupt(False)
                results.append(thread_id)
            except Exception as e:
                errors.append((thread_id, str(e)))
        
        threads = [
            threading.Thread(target=setter_thread, args=(i,))
            for i in range(5)
        ]
        
        for t in threads:
            t.start()
        for t in threads:
            t.join(timeout=10)
        
        assert len(errors) == 0, f"Thread errors: {errors}"
        assert len(results) == 5
    
    def test_concurrent_read_write(self):
        """Test concurrent reads and writes are consistent."""
        set_interrupt(False)
        
        read_results = []
        write_done = threading.Event()
        
        def reader():
            while not write_done.is_set():
                _ = is_interrupted()
                _ = get_interrupt_count()
        
        def writer():
            for _ in range(500):
                set_interrupt(True)
                set_interrupt(False)
            write_done.set()
        
        readers = [threading.Thread(target=reader) for _ in range(3)]
        writer_t = threading.Thread(target=writer)
        
        for r in readers:
            r.start()
        writer_t.start()
        
        writer_t.join(timeout=15)
        write_done.set()
        for r in readers:
            r.join(timeout=5)
        
        # No assertion needed - test passes if no exceptions/deadlocks


class TestInterruptibleContext:
    """Test InterruptibleContext helper."""
    
    def test_context_manager(self):
        """Test context manager basic usage."""
        set_interrupt(False)
        
        with InterruptibleContext() as ctx:
            for _ in range(10):
                assert ctx.should_continue() is True
        
        assert is_interrupted() is False
    
    def test_context_respects_interrupt(self):
        """Test that context stops on interrupt."""
        set_interrupt(False)
        
        with InterruptibleContext(check_interval=5) as ctx:
            # Simulate work
            for i in range(20):
                if i == 10:
                    set_interrupt(True)
                if not ctx.should_continue():
                    break
        
        # Should have been interrupted
        assert is_interrupted() is True
        set_interrupt(False)  # Cleanup


class TestWaitForInterrupt:
    """Test wait_for_interrupt functionality."""
    
    def test_wait_with_timeout(self):
        """Test wait returns False on timeout."""
        set_interrupt(False)
        
        start = time.time()
        result = wait_for_interrupt(timeout=0.1)
        elapsed = time.time() - start
        
        assert result is False
        assert elapsed < 0.5  # Should not hang
    
    def test_wait_interruptible(self):
        """Test wait returns True when interrupted."""
        set_interrupt(False)
        
        def delayed_interrupt():
            time.sleep(0.1)
            set_interrupt(True)
        
        t = threading.Thread(target=delayed_interrupt)
        t.start()
        
        start = time.time()
        result = wait_for_interrupt(timeout=5.0)
        elapsed = time.time() - start
        
        t.join(timeout=5)
        
        assert result is True
        assert elapsed < 1.0  # Should return quickly after interrupt
        
        set_interrupt(False)  # Cleanup