import re

import dgl
import pytest
import torch
from dgl import graphbolt as gb
from torch.testing import assert_close


def test_ItemSet_names():
    # ItemSet with single name.
    item_set = gb.ItemSet(torch.arange(0, 5), names="seed_node")
    assert item_set.names == ("seed_node",)

    # ItemSet with multiple names.
    item_set = gb.ItemSet(
        (torch.arange(0, 5), torch.arange(5, 10)), names=("seed_node", "label")
    )
    assert item_set.names == ("seed_node", "label")

    # ItemSet with no name.
    item_set = gb.ItemSet(torch.arange(0, 5))
    assert item_set.names is None

    # ItemSet with mismatched items and names.
    with pytest.raises(
        AssertionError,
        match=re.escape("Number of items (1) and names (2) must match."),
    ):
        _ = gb.ItemSet(torch.arange(0, 5), names=("seed_node", "label"))


def test_ItemSetDict_names():
    # ItemSetDict with single name.
    item_set = gb.ItemSetDict(
        {
            "user": gb.ItemSet(torch.arange(0, 5), names="seed_node"),
            "item": gb.ItemSet(torch.arange(5, 10), names="seed_node"),
        }
    )
    assert item_set.names == ("seed_node",)

    # ItemSetDict with multiple names.
    item_set = gb.ItemSetDict(
        {
            "user": gb.ItemSet(
                (torch.arange(0, 5), torch.arange(5, 10)),
                names=("seed_node", "label"),
            ),
            "item": gb.ItemSet(
                (torch.arange(5, 10), torch.arange(10, 15)),
                names=("seed_node", "label"),
            ),
        }
    )
    assert item_set.names == ("seed_node", "label")

    # ItemSetDict with no name.
    item_set = gb.ItemSetDict(
        {
            "user": gb.ItemSet(torch.arange(0, 5)),
            "item": gb.ItemSet(torch.arange(5, 10)),
        }
    )
    assert item_set.names is None

    # ItemSetDict with mismatched items and names.
    with pytest.raises(
        AssertionError,
        match=re.escape("All itemsets must have the same names."),
    ):
        _ = gb.ItemSetDict(
            {
                "user": gb.ItemSet(
                    (torch.arange(0, 5), torch.arange(5, 10)),
                    names=("seed_node", "label"),
                ),
                "item": gb.ItemSet(
                    (torch.arange(5, 10),), names=("seed_node",)
                ),
            }
        )


def test_ItemSet_valid_length():
    # Single iterable.
    ids = torch.arange(0, 5)
    item_set = gb.ItemSet(ids)
    assert len(item_set) == 5

    # Tuple of iterables.
    node_pairs = (torch.arange(0, 5), torch.arange(5, 10))
    item_set = gb.ItemSet(node_pairs)
    assert len(item_set) == 5


def test_ItemSet_invalid_length():
    class InvalidLength:
        def __iter__(self):
            return iter([0, 1, 2])

    # Single iterable.
    item_set = gb.ItemSet(InvalidLength())
    with pytest.raises(TypeError):
        _ = len(item_set)

    # Tuple of iterables.
    item_set = gb.ItemSet((InvalidLength(), InvalidLength()))
    with pytest.raises(TypeError):
        _ = len(item_set)


def test_ItemSetDict_valid_length():
    # Single iterable.
    user_ids = torch.arange(0, 5)
    item_ids = torch.arange(0, 5)
    item_set = gb.ItemSetDict(
        {
            "user": gb.ItemSet(user_ids),
            "item": gb.ItemSet(item_ids),
        }
    )
    assert len(item_set) == len(user_ids) + len(item_ids)

    # Tuple of iterables.
    like = (torch.arange(0, 5), torch.arange(0, 5))
    follow = (torch.arange(0, 5), torch.arange(5, 10))
    item_set = gb.ItemSetDict(
        {
            "user:like:item": gb.ItemSet(like),
            "user:follow:user": gb.ItemSet(follow),
        }
    )
    assert len(item_set) == len(like[0]) + len(follow[0])


def test_ItemSetDict_invalid_length():
    class InvalidLength:
        def __iter__(self):
            return iter([0, 1, 2])

    # Single iterable.
    item_set = gb.ItemSetDict(
        {
            "user": gb.ItemSet(InvalidLength()),
            "item": gb.ItemSet(InvalidLength()),
        }
    )
    with pytest.raises(TypeError):
        _ = len(item_set)

    # Tuple of iterables.
    item_set = gb.ItemSetDict(
        {
            "user:like:item": gb.ItemSet((InvalidLength(), InvalidLength())),
            "user:follow:user": gb.ItemSet((InvalidLength(), InvalidLength())),
        }
    )
    with pytest.raises(TypeError):
        _ = len(item_set)


def test_ItemSet_node_edge_ids():
    # Node or edge IDs.
    item_set = gb.ItemSet(torch.arange(0, 5))
    for i, item in enumerate(item_set):
        assert i == item.item()


def test_ItemSet_graphs():
    # Graphs.
    graphs = [dgl.rand_graph(10, 20) for _ in range(5)]
    item_set = gb.ItemSet(graphs)
    for i, item in enumerate(item_set):
        assert graphs[i] == item


def test_ItemSet_node_pairs():
    # Node pairs.
    node_pairs = (torch.arange(0, 5), torch.arange(5, 10))
    item_set = gb.ItemSet(node_pairs)
    for i, (src, dst) in enumerate(item_set):
        assert node_pairs[0][i] == src
        assert node_pairs[1][i] == dst


def test_ItemSet_node_pairs_labels():
    # Node pairs and labels
    node_pairs = (torch.arange(0, 5), torch.arange(5, 10))
    labels = torch.randint(0, 3, (5,))
    item_set = gb.ItemSet((node_pairs[0], node_pairs[1], labels))
    for i, (src, dst, label) in enumerate(item_set):
        assert node_pairs[0][i] == src
        assert node_pairs[1][i] == dst
        assert labels[i] == label


def test_ItemSet_head_tail_neg_tails():
    # Head, tail and negative tails.
    heads = torch.arange(0, 5)
    tails = torch.arange(5, 10)
    neg_tails = torch.arange(10, 20).reshape(5, 2)
    item_set = gb.ItemSet((heads, tails, neg_tails))
    for i, (head, tail, negs) in enumerate(item_set):
        assert heads[i] == head
        assert tails[i] == tail
        assert_close(neg_tails[i], negs)


def test_ItemSetDict_node_edge_ids():
    # Node or edge IDs
    ids = {
        "user:like:item": gb.ItemSet(torch.arange(0, 5)),
        "user:follow:user": gb.ItemSet(torch.arange(0, 5)),
    }
    chained_ids = []
    for key, value in ids.items():
        chained_ids += [(key, v) for v in value]
    item_set = gb.ItemSetDict(ids)
    for i, item in enumerate(item_set):
        assert len(item) == 1
        assert isinstance(item, dict)
        assert chained_ids[i][0] in item
        assert item[chained_ids[i][0]] == chained_ids[i][1]


def test_ItemSetDict_node_pairs():
    # Node pairs.
    node_pairs = (torch.arange(0, 5), torch.arange(5, 10))
    node_pairs_dict = {
        "user:like:item": gb.ItemSet(node_pairs),
        "user:follow:user": gb.ItemSet(node_pairs),
    }
    expected_data = []
    for key, value in node_pairs_dict.items():
        expected_data += [(key, v) for v in value]
    item_set = gb.ItemSetDict(node_pairs_dict)
    for i, item in enumerate(item_set):
        assert len(item) == 1
        assert isinstance(item, dict)
        assert expected_data[i][0] in item
        assert item[expected_data[i][0]] == expected_data[i][1]


def test_ItemSetDict_node_pairs_labels():
    # Node pairs and labels
    node_pairs = (torch.arange(0, 5), torch.arange(5, 10))
    labels = torch.randint(0, 3, (5,))
    node_pairs_dict = {
        "user:like:item": gb.ItemSet((node_pairs[0], node_pairs[1], labels)),
        "user:follow:user": gb.ItemSet((node_pairs[0], node_pairs[1], labels)),
    }
    expected_data = []
    for key, value in node_pairs_dict.items():
        expected_data += [(key, v) for v in value]
    item_set = gb.ItemSetDict(node_pairs_dict)
    for i, item in enumerate(item_set):
        assert len(item) == 1
        assert isinstance(item, dict)
        assert expected_data[i][0] in item
        assert item[expected_data[i][0]] == expected_data[i][1]


def test_ItemSetDict_head_tail_neg_tails():
    # Head, tail and negative tails.
    heads = torch.arange(0, 5)
    tails = torch.arange(5, 10)
    neg_tails = torch.arange(10, 20).reshape(5, 2)
    item_set = gb.ItemSet((heads, tails, neg_tails))
    data_dict = {
        "user:like:item": gb.ItemSet((heads, tails, neg_tails)),
        "user:follow:user": gb.ItemSet((heads, tails, neg_tails)),
    }
    expected_data = []
    for key, value in data_dict.items():
        expected_data += [(key, v) for v in value]
    item_set = gb.ItemSetDict(data_dict)
    for i, item in enumerate(item_set):
        assert len(item) == 1
        assert isinstance(item, dict)
        assert expected_data[i][0] in item
        assert_close(item[expected_data[i][0]], expected_data[i][1])
