"""Tests for services (parser, grid_generator, metrics)."""

import pytest
from app.services.parser import (
    parse_initial_state,
    parse_traffic,
    parse_full_state,
    format_initial_state,
    format_traffic,
)
from app.services.grid_generator import gen_grid
from app.services.metrics import MetricsCollector, measure_performance
from app.models.entities import Store, Destination, Tunnel


class TestParseInitialState:
    """Tests for parse_initial_state function."""

    def test_parse_basic(self):
        """Test parsing basic initial state."""
        initial_state = "5;5;2;1;1,2,3,4;;0,0"
        width, height, stores, destinations, tunnels = parse_initial_state(initial_state)

        assert width == 5
        assert height == 5
        assert len(stores) == 1
        assert len(destinations) == 2
        assert len(tunnels) == 0

    def test_parse_with_tunnels(self):
        """Test parsing initial state with tunnels."""
        initial_state = "10;10;3;2;1,1,5,5,8,8;0,0,9,9,2,2,7,7;0,0,9,9"
        width, height, stores, destinations, tunnels = parse_initial_state(initial_state)

        assert width == 10
        assert height == 10
        assert len(stores) == 2
        assert len(destinations) == 3
        assert len(tunnels) == 2

        # Check tunnel entrances
        assert tunnels[0].entrance1 == (0, 0)
        assert tunnels[0].entrance2 == (9, 9)
        assert tunnels[1].entrance1 == (2, 2)
        assert tunnels[1].entrance2 == (7, 7)

    def test_parse_store_positions(self):
        """Test parsing store positions."""
        initial_state = "5;5;1;2;2,2;;0,0,4,4"
        width, height, stores, destinations, tunnels = parse_initial_state(initial_state)

        assert len(stores) == 2
        assert stores[0].position == (0, 0)
        assert stores[1].position == (4, 4)

    def test_parse_destination_positions(self):
        """Test parsing destination positions."""
        initial_state = "5;5;3;1;1,1,2,2,3,3;;0,0"
        width, height, stores, destinations, tunnels = parse_initial_state(initial_state)

        assert len(destinations) == 3
        assert destinations[0].position == (1, 1)
        assert destinations[1].position == (2, 2)
        assert destinations[2].position == (3, 3)

    def test_parse_empty_tunnels(self):
        """Test parsing with no tunnels."""
        initial_state = "3;3;1;1;1,1;;0,0"
        width, height, stores, destinations, tunnels = parse_initial_state(initial_state)

        assert len(tunnels) == 0

    def test_parse_empty_destinations(self):
        """Test parsing with no destinations."""
        initial_state = "3;3;0;1;;;0,0"
        width, height, stores, destinations, tunnels = parse_initial_state(initial_state)

        assert len(destinations) == 0


class TestParseTraffic:
    """Tests for parse_traffic function."""

    def test_parse_basic_traffic(self):
        """Test parsing basic traffic string."""
        traffic_str = "0,0,1,0,2;0,0,0,1,3;1,0,1,1,1"
        grid = parse_traffic(traffic_str, 3, 3)

        assert grid.width == 3
        assert grid.height == 3
        assert grid.get_traffic((0, 0), (1, 0)) == 2
        assert grid.get_traffic((0, 0), (0, 1)) == 3
        assert grid.get_traffic((1, 0), (1, 1)) == 1

    def test_parse_blocked_segment(self):
        """Test parsing blocked segment (traffic=0)."""
        traffic_str = "0,0,1,0,0;0,0,0,1,1"
        grid = parse_traffic(traffic_str, 2, 2)

        assert grid.is_blocked((0, 0), (1, 0)) is True
        assert grid.is_blocked((0, 0), (0, 1)) is False

    def test_parse_empty_traffic(self):
        """Test parsing empty traffic string - should create default traffic."""
        grid = parse_traffic("", 3, 3)

        assert grid.width == 3
        assert grid.height == 3
        # Should have default traffic level 1
        assert grid.get_traffic((0, 0), (1, 0)) == 1
        assert grid.get_traffic((0, 0), (0, 1)) == 1


class TestParseFullState:
    """Tests for parse_full_state function."""

    def test_parse_full_state(self):
        """Test parsing complete state."""
        initial_state = "5;5;2;1;1,1,3,3;;0,0"
        traffic_str = "0,0,1,0,2;0,0,0,1,1"

        state = parse_full_state(initial_state, traffic_str)

        assert state.grid.width == 5
        assert state.grid.height == 5
        assert len(state.stores) == 1
        assert len(state.destinations) == 2
        assert len(state.tunnels) == 0


class TestFormatInitialState:
    """Tests for format_initial_state function."""

    def test_format_basic(self):
        """Test formatting basic state."""
        stores = [Store(id=1, position=(0, 0))]
        destinations = [Destination(id=1, position=(2, 2))]
        tunnels = []

        result = format_initial_state(5, 5, stores, destinations, tunnels)

        assert result == "5;5;1;1;2,2;;0,0"

    def test_format_with_tunnels(self):
        """Test formatting state with tunnels."""
        stores = [Store(id=1, position=(0, 0)), Store(id=2, position=(4, 4))]
        destinations = [Destination(id=1, position=(2, 2))]
        tunnels = [Tunnel(entrance1=(1, 1), entrance2=(3, 3))]

        result = format_initial_state(5, 5, stores, destinations, tunnels)

        assert result == "5;5;1;2;2,2;1,1,3,3;0,0,4,4"

    def test_format_roundtrip(self):
        """Test that format and parse are inverses."""
        stores = [Store(id=1, position=(0, 0)), Store(id=2, position=(4, 4))]
        destinations = [
            Destination(id=1, position=(1, 1)),
            Destination(id=2, position=(3, 3)),
        ]
        tunnels = [Tunnel(entrance1=(0, 4), entrance2=(4, 0))]

        formatted = format_initial_state(5, 5, stores, destinations, tunnels)
        width, height, parsed_stores, parsed_dests, parsed_tunnels = parse_initial_state(formatted)

        assert width == 5
        assert height == 5
        assert len(parsed_stores) == 2
        assert len(parsed_dests) == 2
        assert len(parsed_tunnels) == 1
        assert parsed_stores[0].position == (0, 0)
        assert parsed_stores[1].position == (4, 4)


class TestFormatTraffic:
    """Tests for format_traffic function."""

    def test_format_traffic(self, simple_grid):
        """Test formatting traffic."""
        result = format_traffic(simple_grid)

        # Should contain semicolon-separated segments
        assert ";" in result or len(simple_grid.segments) <= 1

        # Parse it back and verify
        parsed_grid = parse_traffic(result, 3, 3)
        assert parsed_grid.width == 3
        assert parsed_grid.height == 3


class TestGridGenerator:
    """Tests for grid generator."""

    def test_gen_grid_basic(self):
        """Test basic grid generation."""
        initial_state, traffic, state = gen_grid(
            width=5,
            height=5,
            num_stores=1,
            num_destinations=2,
            obstacle_density=0.0,
            seed=42,
        )

        assert state.grid.width == 5
        assert state.grid.height == 5
        assert len(state.stores) == 1
        assert len(state.destinations) == 2
        # Tunnels may be generated randomly since 0 is treated as falsy

    def test_gen_grid_with_tunnels(self):
        """Test grid generation with tunnels."""
        initial_state, traffic, state = gen_grid(
            width=10,
            height=10,
            num_stores=2,
            num_destinations=3,
            num_tunnels=2,
            obstacle_density=0.1,
            seed=42,
        )

        assert len(state.stores) == 2
        assert len(state.destinations) == 3
        # Tunnels might be fewer if generation fails to find valid positions
        assert len(state.tunnels) <= 2

    def test_gen_grid_reproducible(self):
        """Test that same seed produces same grid."""
        result1 = gen_grid(width=5, height=5, seed=12345)
        result2 = gen_grid(width=5, height=5, seed=12345)

        assert result1[0] == result2[0]  # Same initial_state
        assert result1[1] == result2[1]  # Same traffic

    def test_gen_grid_stores_limited(self):
        """Test that stores are limited to max 3."""
        _, _, state = gen_grid(
            width=10,
            height=10,
            num_stores=10,  # Request 10, should get max 3
            num_destinations=1,
            seed=42,
        )

        assert len(state.stores) <= 3

    def test_gen_grid_destinations_limited(self):
        """Test that destinations are limited to max 10."""
        _, _, state = gen_grid(
            width=10,
            height=10,
            num_stores=1,
            num_destinations=20,  # Request 20, should get max 10
            seed=42,
        )

        assert len(state.destinations) <= 10

    def test_gen_grid_connectivity(self):
        """Test that generated grid has connected paths."""
        _, _, state = gen_grid(
            width=5,
            height=5,
            num_stores=1,
            num_destinations=1,
            obstacle_density=0.2,
            seed=42,
        )

        # Should be able to reach destination from store
        # This is ensured by _ensure_connectivity in grid_generator
        store_pos = state.stores[0].position
        dest_pos = state.destinations[0].position

        # BFS to check connectivity
        visited = {store_pos}
        queue = [store_pos]
        while queue:
            current = queue.pop(0)
            if current == dest_pos:
                break
            for neighbor in state.grid.get_neighbors(current):
                if neighbor not in visited:
                    visited.add(neighbor)
                    queue.append(neighbor)

        assert dest_pos in visited, "Destination should be reachable from store"


class TestMetricsCollector:
    """Tests for MetricsCollector."""

    def test_metrics_collector_basic(self):
        """Test basic metrics collection."""
        collector = MetricsCollector()
        collector.start()

        # Do some work
        _ = [i**2 for i in range(1000)]

        collector.sample()
        collector.stop()

        assert collector.runtime_ms > 0
        assert collector.memory_kb >= 0
        assert collector.cpu_percent >= 0

    def test_metrics_collector_multiple_samples(self):
        """Test multiple samples."""
        collector = MetricsCollector()
        collector.start()

        for _ in range(3):
            collector.sample()

        collector.stop()

        assert len(collector.memory_samples) >= 3
        assert len(collector.cpu_samples) >= 3

    def test_measure_performance_context_manager(self):
        """Test measure_performance context manager."""
        with measure_performance() as metrics:
            # Do some work
            _ = sum(range(10000))
            metrics.sample()

        assert metrics.runtime_ms > 0