# Register block of RV32I
# Set and get using [] with the name of the register (lowercase) or the
# position
from ctypes import c_uint32

def defaultGetter(self, pos):
    return self.data[pos]

def defaultSetter(self, pos, val):
    self.data[pos] = val

def zeroSetter(self, pos, val):
    # hardwired to zero
    self.data[pos] = c_uint32(0)


class RegistersRV32I:

    def __init__(self):
        self.names = {}
        self.data = []

        self.setter = []
        self.getter = []

        self.lastChange = None

        self.addRegister(("x0","zero"), setter = zeroSetter)
        self.addRegister(("x1","ra"))
        self.addRegister(("x2","sp", "v0"))
        self.addRegister(("x3","gp", "v1"))
        self.addRegister(("x4","tp"))
        self.addRegister(("x5","t0"))
        self.addRegister(("x6","t1"))
        self.addRegister(("x7","t2"))
        self.addRegister(("x8","s0","fp"))
        self.addRegister(("x9","s1"))
        self.addRegister(("x10","a0"))
        self.addRegister(("x11","a1"))
        self.addRegister(("x12","a2"))
        self.addRegister(("x13","a3"))
        self.addRegister(("x14","a4"))
        self.addRegister(("x15","a5"))
        self.addRegister(("x16","a6"))
        self.addRegister(("x17","a7"))
        self.addRegister(("x18","s2"))
        self.addRegister(("x19","s3"))
        self.addRegister(("x20","s4"))
        self.addRegister(("x21","s5"))
        self.addRegister(("x22","s6"))
        self.addRegister(("x23","s7"))
        self.addRegister(("x24","s8"))
        self.addRegister(("x25","s9"))
        self.addRegister(("x26","s10"))
        self.addRegister(("x27","s11"))
        self.addRegister(("x28","t3"))
        self.addRegister(("x29","t4"))
        self.addRegister(("x30","t5"))
        self.addRegister(("x31","t6"))


    def addRegister(self, names, getter=defaultGetter, setter=defaultSetter):
        for name in names:
            if name in self.names:
                raise KeyError("Register name already in use")

        currentpos = len(self.data)
        for name in names:
            self.names[name] = currentpos
        self.data.append(c_uint32(0))

        self.getter.append(getter)
        self.setter.append(setter)

    def getPos(self, el):
        if isinstance(el, str):
            pos = self.names[el]
        elif isinstance(el, int):
            pos = el
        else:
            raise ValueError("Wrong type of register id. Must be str or int")
        return pos

    def __getitem__(self, el):
        pos = self.getPos(el)
        return self.getter[pos](self, pos)

    def __setitem__(self, el, val):
        pos = self.getPos(el)

        if val > 0xFFFFFFFF:
            raise ValueError("Value is larger than size of the register")
        val = c_uint32(val)
        self.setter[pos](self, pos, val)
        self.lastChange = pos


    def __str__(self):

        out = "   "
        out += "-" * 67
        out += "\n"
        for i,d in enumerate(self.data):
            out += "->" if i == self.lastChange  else "  "
            out += f" | {d.value:#13} | {d.value:#010x} | {d.value:#034b} |"
            out += "\n"
        out += "   "
        out += "-" * 67
        out += "\n"
        return out


if __name__ == "__main__":
    Regs = RegistersRV32I()
    Regs[0] = 1
    Regs["x1"] = 10
    print(Regs)