from sympy import I, symbols, Symbol, sqrt, expand, Integer, srepr

from sympy.physics.quantum.anticommutator import AntiCommutator
from sympy.physics.quantum.commutator import Commutator
from sympy.physics.quantum.dagger import Dagger
from sympy.physics.quantum.operator import Operator
from sympy.physics.quantum.qapply import qapply
from sympy.physics.quantum.constants import hbar
from sympy.physics.quantum.spin import (
    Jx, Jy, Jz, Jplus, Jminus, J2,
    JzKet, JzBra, JxKet, JxBra
)
from sympy.physics.quantum.gate import H
from sympy.physics.quantum.qubit import Qubit


j = Symbol('j')
m = Symbol('m')
jp = Symbol("j'")
mp = Symbol("m'")

z = JzKet(1,0)
po = JzKet(1,1)
mo = JzKet(1,-1)

A = Operator('A')


class Foo(Operator):

    def _apply_operator_JzKet(self, ket, **options):
        return ket


def test_basic():
    assert qapply(Jz*po) == hbar*po
    assert qapply(Jx*z) == hbar*po/sqrt(2) + hbar*mo/sqrt(2)
    assert qapply((Jplus + Jminus)*z/sqrt(2)) == hbar*po + hbar*mo
    assert qapply(Jz*(po + mo)) == hbar*po - hbar*mo
    assert qapply(Jz*po + Jz*mo) == hbar*po - hbar*mo
    assert qapply(Jminus*Jminus*po) == 2*hbar**2*mo
    assert qapply(Jplus**2*mo) == 2*hbar**2*po
    assert qapply(Jplus**2*Jminus**2*po) == 4*hbar**4*po


def test_extra():
    extra = z.dual*A*z
    assert qapply(Jz*po*extra) == hbar*po*extra
    assert qapply(Jx*z*extra) == (hbar*po/sqrt(2) + hbar*mo/sqrt(2))*extra
    assert qapply((Jplus + Jminus)*z/sqrt(2)*extra) == hbar*po*extra + hbar*mo*extra
    assert qapply(Jz*(po + mo)*extra) == hbar*po*extra - hbar*mo*extra
    assert qapply(Jz*po*extra + Jz*mo*extra) == hbar*po*extra - hbar*mo*extra
    assert qapply(Jminus*Jminus*po*extra) == 2*hbar**2*mo*extra
    assert qapply(Jplus**2*mo*extra) == 2*hbar**2*po*extra
    assert qapply(Jplus**2*Jminus**2*po*extra) == 4*hbar**4*po*extra


def test_innerproduct():
    assert qapply(po.dual*Jz*po, ip_doit=False) == hbar*(po.dual*po)
    assert qapply(po.dual*Jz*po) == hbar


def test_zero():
    assert qapply(0) == 0
    assert qapply(Integer(0)) == 0


def test_commutator():
    assert qapply(Commutator(Jx,Jy)*Jz*po) == I*hbar**3*po
    assert qapply(Commutator(J2, Jz)*Jz*po) == 0
    assert qapply(Commutator(Jz, Foo('F'))*po) == 0
    assert qapply(Commutator(Foo('F'), Jz)*po) == 0


def test_anticommutator():
    assert qapply(AntiCommutator(Jz, Foo('F'))*po) == 2*hbar*po
    assert qapply(AntiCommutator(Foo('F'), Jz)*po) == 2*hbar*po


def test_outerproduct():
    e = Jz*(mo*po.dual)*Jz*po
    assert qapply(e) == -hbar**2*mo
    assert qapply(e, ip_doit=False) == -hbar**2*(po.dual*po)*mo
    assert qapply(e).doit() == -hbar**2*mo


def test_dagger():
    lhs = Dagger(Qubit(0))*Dagger(H(0))
    rhs = Dagger(Qubit(1))/sqrt(2) + Dagger(Qubit(0))/sqrt(2)
    assert qapply(lhs, dagger=True) == rhs
