#!/usr/bin/env python
# PyTensor tutorial
# Solution to Exercise in section 'Extending PyTensor'
import unittest

import pytensor
from pytensor.graph.basic import Apply
from pytensor.graph.op import Op
from pytensor.tensor.type import TensorType


# 1. Op returns x * y


class ProdOp(Op):
    def make_node(self, x, y):
        x = pt.as_tensor_variable(x)
        y = pt.as_tensor_variable(y)
        outdim = x.type.ndim
        output = TensorType(
            dtype=pytensor.scalar.upcast(x.dtype, y.dtype), shape=(None,) * outdim
        )()
        return Apply(self, inputs=[x, y], outputs=[output])

    def perform(self, node, inputs, output_storage):
        x, y = inputs
        z = output_storage[0]
        z[0] = x * y

    def infer_shape(self, fgraph, node, i0_shapes):
        return [i0_shapes[0]]

    def grad(self, inputs, output_grads):
        return [output_grads[0] * inputs[1], output_grads[0] * inputs[0]]


# 2. Op returns x + y and x - y


class SumDiffOp(Op):
    def make_node(self, x, y):
        x = pt.as_tensor_variable(x)
        y = pt.as_tensor_variable(y)
        outdim = x.type.ndim
        output1 = TensorType(
            dtype=pytensor.scalar.upcast(x.dtype, y.dtype), shape=(None,) * outdim
        )()
        output2 = TensorType(
            dtype=pytensor.scalar.upcast(x.dtype, y.dtype), shape=(None,) * outdim
        )()
        return Apply(self, inputs=[x, y], outputs=[output1, output2])

    def perform(self, node, inputs, output_storage):
        x, y = inputs
        z1, z2 = output_storage
        z1[0] = x + y
        z2[0] = x - y

    def infer_shape(self, fgraph, node, i0_shapes):
        return [i0_shapes[0], i0_shapes[0]]

    def grad(self, inputs, output_grads):
        og1, og2 = output_grads
        if og1 is None:
            og1 = pt.zeros_like(og2)
        if og2 is None:
            og2 = pt.zeros_like(og1)
        return [og1 + og2, og1 - og2]


# 3. Testing apparatus
from tests import unittest_tools as utt
from pytensor import tensor as pt
from pytensor.graph.basic import Apply
from pytensor.tensor.type import dmatrix, matrix


class TestProdOp(utt.InferShapeTester):
    def setup_method(self):
        super().setup_method()
        self.op_class = ProdOp  # case 1

    def test_perform(self):
        rng = np.random.default_rng(43)
        x = matrix()
        y = matrix()
        f = pytensor.function([x, y], self.op_class()(x, y))
        x_val = rng.random((5, 4))
        y_val = rng.random((5, 4))
        out = f(x_val, y_val)
        assert np.allclose(x_val * y_val, out)

    def test_gradient(self):
        rng = np.random.default_rng(43)
        utt.verify_grad(
            self.op_class(),
            [rng.random((5, 4)), rng.random((5, 4))],
            n_tests=1,
            rng=TestProdOp.rng,
        )

    def test_infer_shape(self):
        rng = np.random.default_rng(43)
        x = dmatrix()
        y = dmatrix()

        self._compile_and_check(
            [x, y],
            [self.op_class()(x, y)],
            [rng.random(5, 6), rng.random((5, 6))],
            self.op_class,
        )


class TestSumDiffOp(utt.InferShapeTester):
    def setup_method(self):
        super().setup_method()
        self.op_class = SumDiffOp

    def test_perform(self):
        rng = np.random.default_rng(43)
        x = matrix()
        y = matrix()
        f = pytensor.function([x, y], self.op_class()(x, y))
        x_val = rng.random((5, 4))
        y_val = rng.random((5, 4))
        out = f(x_val, y_val)
        assert np.allclose([x_val + y_val, x_val - y_val], out)

    def test_gradient(self):
        rng = np.random.default_rng(43)

        def output_0(x, y):
            return self.op_class()(x, y)[0]

        def output_1(x, y):
            return self.op_class()(x, y)[1]

        utt.verify_grad(
            output_0,
            [rng.random((5, 4)), rng.random((5, 4))],
            n_tests=1,
            rng=TestSumDiffOp.rng,
        )
        utt.verify_grad(
            output_1,
            [rng.random((5, 4)), rng.random((5, 4))],
            n_tests=1,
            rng=TestSumDiffOp.rng,
        )

    def test_infer_shape(self):
        rng = np.random.default_rng(43)

        x = dmatrix()
        y = dmatrix()

        # adapt the choice of the next instruction to the op under test

        self._compile_and_check(
            [x, y],
            self.op_class()(x, y),
            [rng.random((5, 6)), rng.random((5, 6))],
            self.op_class,
        )


import numpy as np

# as_op exercice
import pytensor
from pytensor.compile.ops import as_op


def infer_shape_numpy_dot(fgraph, node, input_shapes):
    ashp, bshp = input_shapes
    return [ashp[:-1] + bshp[-1:]]


@as_op(
    itypes=[pt.fmatrix, pt.fmatrix],
    otypes=[pt.fmatrix],
    infer_shape=infer_shape_numpy_dot,
)
def numpy_add(a, b):
    return np.add(a, b)


def infer_shape_numpy_add_sub(fgraph, node, input_shapes):
    ashp, bshp = input_shapes
    # Both inputs should have that same shape, so we just return one of them.
    return [ashp[0]]


@as_op(
    itypes=[pt.fmatrix, pt.fmatrix],
    otypes=[pt.fmatrix],
    infer_shape=infer_shape_numpy_add_sub,
)
def numpy_add(a, b):
    return np.add(a, b)


@as_op(
    itypes=[pt.fmatrix, pt.fmatrix],
    otypes=[pt.fmatrix],
    infer_shape=infer_shape_numpy_add_sub,
)
def numpy_sub(a, b):
    return np.sub(a, b)


if __name__ == "__main__":
    unittest.main()
