from __future__ import annotations

import asyncio
import contextlib
from copy import deepcopy

import aiostream
import hypothesis.strategies as st
import pytest
from hypothesis import assume
from hypothesis.stateful import Bundle
from hypothesis.stateful import RuleBasedStateMachine
from hypothesis.stateful import rule

from tests import blow_up
from tests import uid_strategy
from vdirsyncer.storage.memory import MemoryStorage
from vdirsyncer.storage.memory import _random_string
from vdirsyncer.sync import sync as _sync
from vdirsyncer.sync.exceptions import BothReadOnly
from vdirsyncer.sync.exceptions import IdentConflict
from vdirsyncer.sync.exceptions import PartialSync
from vdirsyncer.sync.exceptions import StorageEmpty
from vdirsyncer.sync.exceptions import SyncConflict
from vdirsyncer.sync.status import SqliteStatus
from vdirsyncer.vobject import Item


async def sync(a, b, status, *args, **kwargs) -> None:
    with contextlib.closing(SqliteStatus(":memory:")) as new_status:
        new_status.load_legacy_status(status)
        await _sync(a, b, new_status, *args, **kwargs)
        status.clear()
        status.update(new_status.to_legacy_status())


def empty_storage(x):
    return list(x.list()) == []


def items(s):
    return {x[1].raw for x in s.items.values()}


@pytest.mark.asyncio
async def test_irrelevant_status():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {"1": ("1", 1234, "1.ics", 2345)}
    await sync(a, b, status)
    assert not status
    assert not items(a)
    assert not items(b)


@pytest.mark.asyncio
async def test_missing_status():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    item = Item("asdf")
    await a.upload(item)
    await b.upload(item)
    await sync(a, b, status)
    assert len(status) == 1
    assert items(a) == items(b) == {item.raw}


@pytest.mark.asyncio
async def test_missing_status_and_different_items():
    a = MemoryStorage()
    b = MemoryStorage()

    status = {}
    item1 = Item("UID:1\nhaha")
    item2 = Item("UID:1\nhoho")
    await a.upload(item1)
    await b.upload(item2)
    with pytest.raises(SyncConflict):
        await sync(a, b, status)
    assert not status
    await sync(a, b, status, conflict_resolution="a wins")
    assert items(a) == items(b) == {item1.raw}


@pytest.mark.asyncio
async def test_read_only_and_prefetch():
    a = MemoryStorage()
    b = MemoryStorage()
    b.read_only = True

    status = {}
    item1 = Item("UID:1\nhaha")
    item2 = Item("UID:2\nhoho")
    await a.upload(item1)
    await a.upload(item2)

    await sync(a, b, status, force_delete=True)
    await sync(a, b, status, force_delete=True)

    assert not items(a) and not items(b)


@pytest.mark.asyncio
async def test_partial_sync_error():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    await a.upload(Item("UID:0"))
    b.read_only = True

    with pytest.raises(PartialSync):
        await sync(a, b, status, partial_sync="error")


@pytest.mark.asyncio
async def test_partial_sync_ignore():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    item0 = Item("UID:0\nhehe")
    await a.upload(item0)
    await b.upload(item0)

    b.read_only = True

    item1 = Item("UID:1\nhaha")
    await a.upload(item1)

    await sync(a, b, status, partial_sync="ignore")
    await sync(a, b, status, partial_sync="ignore")

    assert items(a) == {item0.raw, item1.raw}
    assert items(b) == {item0.raw}


@pytest.mark.asyncio
async def test_partial_sync_ignore2():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    href, etag = await a.upload(Item("UID:0"))
    a.read_only = True

    await sync(a, b, status, partial_sync="ignore", force_delete=True)
    assert items(b) == items(a) == {"UID:0"}

    b.items.clear()
    await sync(a, b, status, partial_sync="ignore", force_delete=True)
    await sync(a, b, status, partial_sync="ignore", force_delete=True)
    assert items(a) == {"UID:0"}
    assert not b.items

    a.read_only = False
    await a.update(href, Item("UID:0\nupdated"), etag)
    a.read_only = True
    await sync(a, b, status, partial_sync="ignore", force_delete=True)
    assert items(b) == items(a) == {"UID:0\nupdated"}


@pytest.mark.asyncio
async def test_upload_and_update():
    a = MemoryStorage(fileext=".a")
    b = MemoryStorage(fileext=".b")
    status = {}

    item = Item("UID:1")  # new item 1 in a
    await a.upload(item)
    await sync(a, b, status)
    assert items(b) == items(a) == {item.raw}

    item = Item("UID:1\nASDF:YES")  # update of item 1 in b
    await b.update("1.b", item, (await b.get("1.b"))[1])
    await sync(a, b, status)
    assert items(b) == items(a) == {item.raw}

    item2 = Item("UID:2")  # new item 2 in b
    await b.upload(item2)
    await sync(a, b, status)
    assert items(b) == items(a) == {item.raw, item2.raw}

    item2 = Item("UID:2\nASDF:YES")  # update of item 2 in a
    await a.update("2.a", item2, (await a.get("2.a"))[1])
    await sync(a, b, status)
    assert items(b) == items(a) == {item.raw, item2.raw}


@pytest.mark.asyncio
async def test_deletion():
    a = MemoryStorage(fileext=".a")
    b = MemoryStorage(fileext=".b")
    status = {}

    item = Item("UID:1")
    await a.upload(item)
    item2 = Item("UID:2")
    await a.upload(item2)
    await sync(a, b, status)
    await b.delete("1.b", (await b.get("1.b"))[1])
    await sync(a, b, status)
    assert items(a) == items(b) == {item2.raw}

    await a.upload(item)
    await sync(a, b, status)
    assert items(a) == items(b) == {item.raw, item2.raw}
    await a.delete("1.a", (await a.get("1.a"))[1])
    await sync(a, b, status)
    assert items(a) == items(b) == {item2.raw}


@pytest.mark.asyncio
async def test_insert_hash():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    item = Item("UID:1")
    href, etag = await a.upload(item)
    await sync(a, b, status)

    for d in status["1"]:
        del d["hash"]

    await a.update(href, Item("UID:1\nHAHA:YES"), etag)
    await sync(a, b, status)
    assert "hash" in status["1"][0] and "hash" in status["1"][1]


@pytest.mark.asyncio
async def test_already_synced():
    a = MemoryStorage(fileext=".a")
    b = MemoryStorage(fileext=".b")
    item = Item("UID:1")
    await a.upload(item)
    await b.upload(item)
    status = {
        "1": (
            {"href": "1.a", "hash": item.hash, "etag": (await a.get("1.a"))[1]},
            {"href": "1.b", "hash": item.hash, "etag": (await b.get("1.b"))[1]},
        )
    }
    old_status = deepcopy(status)
    a.update = b.update = a.upload = b.upload = lambda *a, **kw: pytest.fail(
        "Method shouldn't have been called."
    )

    for _ in (1, 2):
        await sync(a, b, status)
        assert status == old_status
        assert items(a) == items(b) == {item.raw}


@pytest.mark.parametrize("winning_storage", "ab")
@pytest.mark.asyncio
async def test_conflict_resolution_both_etags_new(winning_storage):
    a = MemoryStorage()
    b = MemoryStorage()
    item = Item("UID:1")
    href_a, etag_a = await a.upload(item)
    href_b, etag_b = await b.upload(item)
    status = {}
    await sync(a, b, status)
    assert status
    item_a = Item("UID:1\nitem a")
    item_b = Item("UID:1\nitem b")
    await a.update(href_a, item_a, etag_a)
    await b.update(href_b, item_b, etag_b)
    with pytest.raises(SyncConflict):
        await sync(a, b, status)
    await sync(a, b, status, conflict_resolution=f"{winning_storage} wins")
    assert (
        items(a) == items(b) == {item_a.raw if winning_storage == "a" else item_b.raw}
    )


@pytest.mark.asyncio
async def test_updated_and_deleted():
    a = MemoryStorage()
    b = MemoryStorage()
    href_a, etag_a = await a.upload(Item("UID:1"))
    status = {}
    await sync(a, b, status, force_delete=True)

    ((href_b, etag_b),) = await aiostream.stream.list(b.list())
    await b.delete(href_b, etag_b)
    updated = Item("UID:1\nupdated")
    await a.update(href_a, updated, etag_a)
    await sync(a, b, status, force_delete=True)

    assert items(a) == items(b) == {updated.raw}


@pytest.mark.asyncio
async def test_conflict_resolution_invalid_mode():
    a = MemoryStorage()
    b = MemoryStorage()
    item_a = Item("UID:1\nitem a")
    item_b = Item("UID:1\nitem b")
    await a.upload(item_a)
    await b.upload(item_b)
    with pytest.raises(ValueError):
        await sync(a, b, {}, conflict_resolution="yolo")


@pytest.mark.asyncio
async def test_conflict_resolution_new_etags_without_changes():
    a = MemoryStorage()
    b = MemoryStorage()
    item = Item("UID:1")
    href_a, etag_a = await a.upload(item)
    href_b, etag_b = await b.upload(item)
    status = {"1": (href_a, "BOGUS_a", href_b, "BOGUS_b")}

    await sync(a, b, status)

    ((ident, (status_a, status_b)),) = status.items()
    assert ident == "1"
    assert status_a["href"] == href_a
    assert status_a["etag"] == etag_a
    assert status_b["href"] == href_b
    assert status_b["etag"] == etag_b


@pytest.mark.asyncio
async def test_uses_get_multi(monkeypatch):
    def breakdown(*a, **kw):
        raise AssertionError("Expected use of get_multi")

    get_multi_calls = []

    old_get = MemoryStorage.get

    async def get_multi(self, hrefs):
        hrefs = list(hrefs)
        get_multi_calls.append(hrefs)
        for href in hrefs:
            item, etag = await old_get(self, href)
            yield href, item, etag

    monkeypatch.setattr(MemoryStorage, "get", breakdown)
    monkeypatch.setattr(MemoryStorage, "get_multi", get_multi)

    a = MemoryStorage()
    b = MemoryStorage()
    item = Item("UID:1")
    expected_href, etag = await a.upload(item)

    await sync(a, b, {})
    assert get_multi_calls == [[expected_href]]


@pytest.mark.asyncio
async def test_empty_storage_dataloss():
    a = MemoryStorage()
    b = MemoryStorage()
    await a.upload(Item("UID:1"))
    await a.upload(Item("UID:2"))
    status = {}
    await sync(a, b, status)
    with pytest.raises(StorageEmpty):
        await sync(MemoryStorage(), b, status)

    with pytest.raises(StorageEmpty):
        await sync(a, MemoryStorage(), status)


@pytest.mark.asyncio
async def test_no_uids():
    a = MemoryStorage()
    b = MemoryStorage()
    await a.upload(Item("ASDF"))
    await b.upload(Item("FOOBAR"))
    status = {}
    await sync(a, b, status)
    assert items(a) == items(b) == {"ASDF", "FOOBAR"}


@pytest.mark.asyncio
async def test_changed_uids():
    a = MemoryStorage()
    b = MemoryStorage()
    href_a, etag_a = await a.upload(Item("UID:A-ONE"))
    href_b, etag_b = await b.upload(Item("UID:B-ONE"))
    status = {}
    await sync(a, b, status)

    await a.update(href_a, Item("UID:A-TWO"), etag_a)
    await sync(a, b, status)


@pytest.mark.asyncio
async def test_both_readonly():
    a = MemoryStorage(read_only=True)
    b = MemoryStorage(read_only=True)
    assert a.read_only
    assert b.read_only
    status = {}
    with pytest.raises(BothReadOnly):
        await sync(a, b, status)


@pytest.mark.asyncio
async def test_partial_sync_revert():
    a = MemoryStorage(instance_name="a")
    b = MemoryStorage(instance_name="b")
    status = {}
    await a.upload(Item("UID:1"))
    await b.upload(Item("UID:2"))
    b.read_only = True

    await sync(a, b, status, partial_sync="revert")
    assert len(status) == 2
    assert items(a) == {"UID:1", "UID:2"}
    assert items(b) == {"UID:2"}

    await sync(a, b, status, partial_sync="revert")
    assert len(status) == 1
    assert items(a) == {"UID:2"}
    assert items(b) == {"UID:2"}

    # Check that updates get reverted
    a.items[next(iter(a.items))] = ("foo", Item("UID:2\nupdated"))
    assert items(a) == {"UID:2\nupdated"}
    await sync(a, b, status, partial_sync="revert")
    assert len(status) == 1
    assert items(a) == {"UID:2\nupdated"}
    await sync(a, b, status, partial_sync="revert")
    assert items(a) == {"UID:2"}

    # Check that deletions get reverted
    a.items.clear()
    await sync(a, b, status, partial_sync="revert", force_delete=True)
    await sync(a, b, status, partial_sync="revert", force_delete=True)
    assert items(a) == {"UID:2"}


@pytest.mark.parametrize("sync_inbetween", (True, False))
@pytest.mark.asyncio
async def test_ident_conflict(sync_inbetween):
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href_a, etag_a = await a.upload(Item("UID:aaa"))
    href_b, etag_b = await a.upload(Item("UID:bbb"))
    if sync_inbetween:
        await sync(a, b, status)

    await a.update(href_a, Item("UID:xxx"), etag_a)
    await a.update(href_b, Item("UID:xxx"), etag_b)

    with pytest.raises(IdentConflict):
        await sync(a, b, status)


@pytest.mark.asyncio
async def test_moved_href():
    """
    Concrete application: ppl_ stores contact aliases in filenames, which means
    item's hrefs get changed. Vdirsyncer doesn't synchronize this data, but
    also shouldn't do things like deleting and re-uploading to the server.

    .. _ppl: http://ppladdressbook.org/
    """
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href, etag = await a.upload(Item("UID:haha"))
    await sync(a, b, status)

    b.items["lol"] = b.items.pop("haha")

    # The sync algorithm should prefetch `lol`, see that it's the same ident
    # and not do anything else.
    a.get_multi = blow_up  # Absolutely no prefetch on A
    # No actual sync actions
    a.delete = a.update = a.upload = b.delete = b.update = b.upload = blow_up

    await sync(a, b, status)
    assert len(status) == 1
    assert items(a) == items(b) == {"UID:haha"}
    assert status["haha"][1]["href"] == "lol"
    old_status = deepcopy(status)

    # Further sync should be a noop. Not even prefetching should occur.
    b.get_multi = blow_up

    await sync(a, b, status)
    assert old_status == status
    assert items(a) == items(b) == {"UID:haha"}


@pytest.mark.asyncio
async def test_bogus_etag_change():
    """Assert that sync algorithm is resilient against etag changes if content
    didn\'t change.

    In this particular case we test a scenario where both etags have been
    updated, but only one side actually changed its item content.
    """
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href_a, etag_a = await a.upload(Item("UID:ASDASD"))
    await sync(a, b, status)
    assert (
        len(status)
        == len(await aiostream.stream.list(a.list()))
        == len(await aiostream.stream.list(b.list()))
        == 1
    )

    ((href_b, etag_b),) = await aiostream.stream.list(b.list())
    await a.update(href_a, Item("UID:ASDASD"), etag_a)
    await b.update(href_b, Item("UID:ASDASD\nACTUALCHANGE:YES"), etag_b)

    b.delete = b.update = b.upload = blow_up

    await sync(a, b, status)
    assert len(status) == 1
    assert items(a) == items(b) == {"UID:ASDASD\nACTUALCHANGE:YES"}


@pytest.mark.asyncio
async def test_unicode_hrefs():
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}
    href, etag = await a.upload(Item("UID:äää"))
    await sync(a, b, status)


class ActionIntentionallyFailed(Exception):
    pass


def action_failure(*a, **kw):
    raise ActionIntentionallyFailed


class SyncMachine(RuleBasedStateMachine):
    Status = Bundle("status")
    Storage = Bundle("storage")

    @rule(target=Storage, flaky_etags=st.booleans(), null_etag_on_upload=st.booleans())
    @pytest.mark.asyncio
    def newstorage(self, flaky_etags, null_etag_on_upload):
        s = MemoryStorage()
        if flaky_etags:

            async def get(href):
                old_etag, item = s.items[href]
                etag = _random_string()
                s.items[href] = etag, item
                return item, etag

            s.get = get

        if null_etag_on_upload:
            _old_upload = s.upload
            _old_update = s.update

            async def upload(item):
                return (await _old_upload(item))[0], "NULL"

            async def update(href, item, etag):
                return await _old_update(href, item, etag) and "NULL"

            s.upload = upload
            s.update = update

        return s

    @rule(s=Storage, read_only=st.booleans())
    def is_read_only(self, s, read_only):
        assume(s.read_only != read_only)
        s.read_only = read_only

    @rule(s=Storage)
    def actions_fail(self, s):
        s.upload = action_failure
        s.update = action_failure
        s.delete = action_failure

    @rule(s=Storage)
    def none_as_etag(self, s):
        _old_upload = s.upload
        _old_update = s.update

        async def upload(item):
            return (await _old_upload(item))[0], None

        async def update(href, item, etag):
            return await _old_update(href, item, etag)

        s.upload = upload
        s.update = update

    @rule(target=Status)
    def newstatus(self):
        return {}

    @rule(storage=Storage, uid=uid_strategy, etag=st.text())
    def upload(self, storage, uid, etag):
        item = Item(f"UID:{uid}")
        storage.items[uid] = (etag, item)

    @rule(storage=Storage, href=st.text())
    def delete(self, storage, href):
        assume(storage.items.pop(href, None))

    @rule(
        status=Status,
        a=Storage,
        b=Storage,
        force_delete=st.booleans(),
        conflict_resolution=st.one_of((st.just("a wins"), st.just("b wins"))),
        with_error_callback=st.booleans(),
        partial_sync=st.one_of(
            (st.just("ignore"), st.just("revert"), st.just("error"))
        ),
    )
    def sync(
        self,
        status,
        a,
        b,
        force_delete,
        conflict_resolution,
        with_error_callback,
        partial_sync,
    ):
        async def inner():
            assume(a is not b)
            old_items_a = items(a)
            old_items_b = items(b)

            a.instance_name = "a"
            b.instance_name = "b"

            errors = []

            if with_error_callback:
                error_callback = errors.append
            else:
                error_callback = None

            try:
                # If one storage is read-only, double-sync because changes don't
                # get reverted immediately.
                for _ in range(2 if a.read_only or b.read_only else 1):
                    await sync(
                        a,
                        b,
                        status,
                        force_delete=force_delete,
                        conflict_resolution=conflict_resolution,
                        error_callback=error_callback,
                        partial_sync=partial_sync,
                    )

                for e in errors:
                    raise e
            except PartialSync:
                assert partial_sync == "error"
            except ActionIntentionallyFailed:
                pass
            except BothReadOnly:
                assert a.read_only and b.read_only
                assume(False)
            except StorageEmpty:
                if force_delete:
                    raise
                else:
                    not_a = not await aiostream.stream.list(a.list())
                    not_b = not await aiostream.stream.list(b.list())
                    assert not_a or not_b
            else:
                items_a = items(a)
                items_b = items(b)

                assert items_a == items_b or partial_sync == "ignore"
                assert items_a == old_items_a or not a.read_only
                assert items_b == old_items_b or not b.read_only

                assert (
                    set(a.items) | set(b.items) == set(status)
                    or partial_sync == "ignore"
                )

        asyncio.run(inner())


TestSyncMachine = SyncMachine.TestCase


@pytest.mark.parametrize("error_callback", [True, False])
@pytest.mark.asyncio
async def test_rollback(error_callback):
    a = MemoryStorage()
    b = MemoryStorage()
    status = {}

    a.items["0"] = ("", Item("UID:0"))
    b.items["1"] = ("", Item("UID:1"))

    b.upload = b.update = b.delete = action_failure

    if error_callback:
        errors = []

        await sync(
            a,
            b,
            status=status,
            conflict_resolution="a wins",
            error_callback=errors.append,
        )

        assert len(errors) == 1
        assert isinstance(errors[0], ActionIntentionallyFailed)

        assert len(status) == 1
        assert status["1"]
    else:
        with pytest.raises(ActionIntentionallyFailed):
            await sync(a, b, status=status, conflict_resolution="a wins")


@pytest.mark.asyncio
async def test_duplicate_hrefs():
    a = MemoryStorage()
    b = MemoryStorage()

    async def fake_list():
        for item in [("a", "a")] * 3:
            yield item

    a.list = fake_list
    a.items["a"] = ("a", Item("UID:a"))

    status = {}
    await sync(a, b, status)
    with pytest.raises(AssertionError):
        await sync(a, b, status)