import numpy as np

import pytensor
import pytensor.tensor as at
from pytensor import function
from pytensor import scalar as aes
from pytensor.configdefaults import config
from pytensor.graph.fg import FunctionGraph
from pytensor.graph.rewriting.basic import out2in
from pytensor.link.basic import PerformLinker
from pytensor.tensor.elemwise import CAReduce, DimShuffle, Elemwise
from pytensor.tensor.math import MaxAndArgmax
from pytensor.tensor.math import max as at_max
from pytensor.tensor.math import max_and_argmax
from pytensor.tensor.math import min as at_min
from pytensor.tensor.rewriting.uncanonicalize import (
    local_alloc_dimshuffle,
    local_dimshuffle_alloc,
    local_dimshuffle_subtensor,
    local_reshape_dimshuffle,
)
from pytensor.tensor.shape import reshape, specify_shape
from pytensor.tensor.type import dtensor4, iscalar, matrix, tensor, vector
from tests.link.test_link import make_function


class TestMaxAndArgmax:
    def test_optimization(self):
        # If we use only the max output, we should replace this op with
        # a faster one.
        mode = pytensor.compile.mode.get_default_mode().including(
            "canonicalize", "fast_run"
        )

        for axis in [0, 1, -1]:
            n = matrix()

            f = function([n], max_and_argmax(n, axis)[0], mode=mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 1
            assert isinstance(topo[0].op, CAReduce)

            f = function([n], max_and_argmax(n, axis), mode=mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 1
            assert isinstance(topo[0].op, MaxAndArgmax)


class TestMinMax:
    def setup_method(self):
        self.mode = pytensor.compile.mode.get_default_mode().including(
            "canonicalize", "fast_run"
        )

    def test_optimization_max(self):
        data = np.asarray(np.random.random((2, 3)), dtype=config.floatX)
        n = matrix()

        for axis in [0, 1, -1]:
            f = function([n], at_max(n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 1
            assert isinstance(topo[0].op, CAReduce)
            f(data)

            f = function([n], at_max(-n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 2
            assert isinstance(topo[0].op, Elemwise)
            assert isinstance(topo[0].op.scalar_op, aes.Neg)
            assert isinstance(topo[1].op, CAReduce)
            f(data)

            f = function([n], -at_max(n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 2
            assert isinstance(topo[0].op, CAReduce)
            assert isinstance(topo[1].op, Elemwise)
            assert isinstance(topo[1].op.scalar_op, aes.Neg)
            f(data)

            f = function([n], -at_max(-n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 1
            assert isinstance(topo[0].op, CAReduce)  # min
            f(data)

    def test_optimization_min(self):
        data = np.asarray(np.random.random((2, 3)), dtype=config.floatX)
        n = matrix()

        for axis in [0, 1, -1]:
            f = function([n], at_min(n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 1
            assert isinstance(topo[0].op, CAReduce)
            f(data)

            # test variant with neg to make sure we optimize correctly
            f = function([n], at_min(-n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 2
            assert isinstance(topo[0].op, CAReduce)  # max
            assert isinstance(topo[1].op, Elemwise)
            assert isinstance(topo[1].op.scalar_op, aes.Neg)
            f(data)

            f = function([n], -at_min(n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 2
            assert isinstance(topo[0].op, Elemwise)
            assert isinstance(topo[0].op.scalar_op, aes.Neg)
            assert isinstance(topo[1].op, CAReduce)  # max
            f(data)

            f = function([n], -at_min(-n, axis), mode=self.mode)
            topo = f.maker.fgraph.toposort()
            assert len(topo) == 1
            assert isinstance(topo[0].op, CAReduce)  # max
            f(data)


def test_local_alloc_dimshuffle():

    alloc_dimshuffle = out2in(local_alloc_dimshuffle)

    x = vector("x")
    m = iscalar("m")

    y = x.dimshuffle("x", 0)
    out = at.alloc(y, m, 1, x.shape[0])

    g = FunctionGraph([x, m], [out])
    alloc_dimshuffle(g)

    topo = g.toposort()
    assert not all(isinstance(x, DimShuffle) for x in topo)


def test_local_reshape_dimshuffle():

    reshape_dimshuffle = out2in(local_reshape_dimshuffle)

    x = matrix("x")

    y = x.dimshuffle("x", 0, "x", 1)
    out = reshape(y, (1, x.shape[0] * x.shape[1], 1))

    g = FunctionGraph([x], [out])
    reshape_dimshuffle(g)

    topo = g.toposort()
    assert not all(isinstance(x, DimShuffle) for x in topo)


def test_local_dimshuffle_alloc():

    reshape_dimshuffle = out2in(local_dimshuffle_alloc)

    x = vector("x")

    out = at.alloc(x, 3, 2).dimshuffle("x", "x", 0, 1)

    g = FunctionGraph([x], [out])
    reshape_dimshuffle(g)

    l = PerformLinker()
    l.accept(g)
    f = make_function(l)

    assert f([3, 4]).ndim == 4

    topo = g.toposort()
    assert not all(isinstance(x, DimShuffle) for x in topo)


def test_local_dimshuffle_subtensor():

    dimshuffle_subtensor = out2in(local_dimshuffle_subtensor)

    x = dtensor4("x")
    x = specify_shape(x, (None, 1, None, None))
    i = iscalar("i")

    out = x[:, :, 10:30, ::i].dimshuffle(0, 2, 3)

    g = FunctionGraph([x, i], [out])
    dimshuffle_subtensor(g)

    topo = g.toposort()
    assert not all(isinstance(x, DimShuffle) for x in topo)

    # Test dimshuffle remove dimensions the subtensor don't "see".
    x = tensor(dtype="float64", shape=(None, 1, None))
    out = x[i].dimshuffle(1)

    g = FunctionGraph([x, i], [out])
    dimshuffle_subtensor(g)

    topo = g.toposort()
    assert not all(isinstance(x, DimShuffle) for x in topo)

    # Test dimshuffle remove dimensions the subtensor don't "see" but
    # have in between dimensions.
    x = tensor(dtype="float64", shape=(None, 1, None, 1))
    out = x[i].dimshuffle(1)

    f = pytensor.function([x, i], out)

    topo = f.maker.fgraph.toposort()
    assert not all(isinstance(x, DimShuffle) for x in topo)
    assert f(np.random.random((5, 1, 4, 1)), 2).shape == (4,)

    # Test a corner case that had PyTensor return a bug.
    x = dtensor4("x")
    x = specify_shape(x, (None, 1, None, None))

    assert x[:, :, 0:3, ::-1].dimshuffle(0, 2, 3).eval(
        {x: np.ones((5, 1, 6, 7))}
    ).shape == (5, 3, 7)
