import logging

from .rpnlib import *

logger = logging.getLogger()

class Turmit(object):
    ''' @brief Represent a turmit that act given an RPN expression with an
        infinite looping stack with variable stack size.
    '''
    
    def __init__(self, stack_size=8, **kwargs):
        ''' @brief Instanciated a new Turmit with a programm and a memory stack
            @param stack_size int : stack_size
            @param prog str | RpnExpr | None : turmit programm if None generate
            it randomlt
            @param prog_size int : if prog is generated randomly it will make
            this size
            @param max_int int : maximum integer value + 1
            @param signed_int bool : if True integers are signed
	    @throw ValueError for bad option value
	    @throw RuntimError for bad arguments
        '''
        if stack_size < 2:
            msg = 'Stack size has to be >= 2 but %d given' % (stack_size)
            raise ValueError(msg)

        ## @brief List that represent a stack
        self._stack = [ 0 for _ in range(stack_size)]
        ## @brief Stack head index
        self._cur = stack_size - 1
        ## @brief Stores turmit direction
        self._dir = 0
        ## @brief Stores turmit program
        self._prog = None
        self._prog_sz = 42

        ## @brief Stores maximum int value + 1
        #  @note This limit is handled by @ref rpnlib.RpnOp()
        self._max_int = 0x10000
        ## @brief If True integers are signed
        #  @note This limit is handled by @ref rpnlib.RpnOp()
        self._signed_int = True

        if 'max_int' in kwargs:
            v = kwargs['max_int']
            if v < 1:
                raise ValueError('Maximum int have to be >= 1 but %d found' % v)
            self._max_int = kwargs['max_int']
            del(kwargs['max_int'])
        if 'signed_int' in kwargs:
            self._signed_int = bool(kwargs['signed_int'])
            del(kwargs['signed_int'])
        if 'prog_size' in kwargs:
            v = kwargs['prog_size']
            if v < 2:
                raise ValueError('Prog_size have to be >= 2 but %d found' % v)
            self._prog_sz = v
            del(kwargs['prog_size'])
        if 'prog' in kwargs:
            v = kwargs['prog']
            if isinstance(v, str):
                v = RpnExpr.from_string(v)
            if isinstance(v, RpnExpr):
                self._prog = v
            else:
                msg = 'Str or RpnExpr expected but %s found' % (type(v))
                raise TypeError(msg)
            del(kwargs['prog'])
        if len(kwargs) > 0:
            msg = 'Unexpected arguments : [%s]' % ', '.join(kwargs.keys())
            raise RuntimeError(msg)

        if self._prog is None:
            self._prog = RpnExpr.random(self._prog_sz)

        self.__expr_fun = lambda *args, **kwargs: (0,)

    def __call__(self, **context):
        ''' @brief Exec the RPN expression and return the stack head
            @param context dict : dict with variable values (see @ref rpnlib._var_list)
            @return stack head after RPN
        '''
        context = {k:int(context[k]) % self._max_int for k in context}

        if self.__expr_fun is None:
            self._compile()
        ret = self.__expr_fun(self, **context)
        if isinstance(ret, int):
            return ret

        #self.__ip = 0
        self.__ip = ret[0]

        while self.__ip < len(self._prog):
            sym = self._prog[self.__ip]
            if sym.optype == RpnSymbol.VALUE:
                self._push(sym.value)
            elif sym.optype == RpnSymbol.VARIABLE:
                self._push(context[sym.value.lower()])
            elif sym.optype == RpnSymbol.OPERATION:
                getattr(self, sym.value.lower())()
            self.__ip += 1
        return self.shead

    def _compile(self):
        code = 'def expr_fun(self, x, y, r, g, b):\n'
        for ip, sym in enumerate(self._prog):
            if sym.optype == RpnSymbol.VALUE:
                code += '''
    self._cur += 1
    self._cur %%= len(self._stack)
    self._stack[self._cur] = %d
''' % sym.value
            elif sym.optype == RpnSymbol.VARIABLE:
                code += '''
    self._cur += 1
    self._cur %%= len(self._stack)
    self._stack[self._cur] = %s
''' % sym.value.lower()
            elif sym.value == 'add':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] += a
    self._stack[self._cur] %= self._max_int
'''
            elif sym.value == 'sub':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] = self._stack[self._cur] - a
    if self._stack[self._cur] < 0:
        self._stack[self._cur] += self._max_int
'''
            elif sym.value == 'mul':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] *= a
    self._stack[self._cur] %= self._max_int
'''
            elif sym.value == 'div':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    if a != 0:
        self._stack[self._cur] = self._stack[self._cur] // a
'''
            elif sym.value == 'mod':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    if a != 0:
        self._stack[self._cur] = self._stack[self._cur] % a
'''
            elif sym.value == 'bin_and':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] &= a
'''
            elif sym.value == 'bin_or':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] |= a
'''
            elif sym.value == 'bin_xor':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] ^= a
'''
            elif sym.value == 'lshift':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] = (self._stack[self._cur] << a) % self._max_int
'''
            elif sym.value == 'rshift':
                code += '''
    a = self._stack[self._cur]
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
    self._stack[self._cur] = self._stack[self._cur] >> a
'''
            elif sym.value == 'dup':
                code += '''
    a = self._stack[self._cur]
    self._cur += 1
    self._cur %= len(self._stack)
    self._stack[self._cur] = a
'''
            elif sym.value == 'pop':
                code += '''
    self._cur = (self._cur - 1) if self._cur > 0 else (len(self._stack) - 1)
'''
            else:
                code += '''
    return (%d,)
''' % ip
        code += '''
    return self._stack[self._cur]
'''
        g = {}
        l = {}
        exec(code, g, l)
        self.__expr_fun = l['expr_fun']

    @property
    def shead(self):
        ''' @brief Stack head attribute '''
        return self._stack[self._cur]

    def _pop(self):
        ''' @brief Pops a value from the stack
            
            @note If stack head is 0, set the stack head to len(self._stack) 
            - 1

            @return popped value
        '''
        res = self._stack[self._cur]
        if self._cur <= 0:
            self._cur = len(self._stack) - 1
        else:
            self._cur -= 1
        return res

    def _push(self, val):
        ''' @brief Pushes a value on the stack
            
            @note If no space left on the stack, the head is set to 0
        
            @param val int : value to push
        '''
        self._cur += 1
        if self._cur >= len(self._stack) or abs(self._cur) >= len(self._stack):
            self._cur = 0
        self._stack[self._cur] = self._cast_int(val)

    def _cast_int(self, val):
        ''' @brief Transform integer given Turmit max int and signed_int
            attr
            @param val int : integer to transform
            @return integer
        '''
        val = int(val)
        if self._max_int is not None:
            val %= self._max_int
            if not self._signed_int and val < 0:
                val = self._max_int - val
        return val

    @RpnOp
    def mem_sz(self, new_sz):
        ''' @brief Update memory stack size
        '''
	    
        stksz = len(self._stack)
        new_sz %= 0xFFF
        if new_sz < 2:
            new_sz = 2
        if new_sz > stksz:
            self._stack += [ 0 for _ in range(new_sz - stksz) ]
        elif new_sz < stksz:
            self._stack = self._stack[0:new_sz]
            if self._cur >= new_sz:
                self._cur = 0
    
    @RpnOp
    def add(self, a, b):
        ''' @brief Adds one value to another
            @param a int : value
            @param b int : value to add to a
            @return a + b
        '''
        return a + b

    @RpnOp
    def sub(self, a, b):
        ''' @brief Substitutes a value to another
            @param a int : value
            @param b int : value to substitute to a
            @return a - b
        '''
        return a - b

    @RpnOp
    def bin_and(self, a, b):
        ''' @brief Binary and
             @param a int : value
             @param b int : value
             @return a & b
        '''
        return a & b

    @RpnOp
    def dup(self, a):
        ''' @brief Duplicates stack head
            @param a int : value
            @return a
        '''
        self._push(a)
        return a

    @RpnOp
    def lshift(self, a, b):
        ''' @brief Left shifts a of b
            @param a int : value
            @param b int : value
            @return a << b
        ''' 
        return a << b

    @RpnOp
    def mod(self, a, b):
        ''' @brief Gives a modulo b
            @param a int : value
            @param b int : value
            @return a % b
        '''
        return a % b

    
    @RpnOp
    def mul(self, a, b):
        ''' @brief Multiplies a with b
            @param a int : value
            @param b int : value
            @return a * b
        '''
        return a * b

    @RpnOp
    def div(self, a, b):
        ''' @brief Divides a with b
            @param a int : value
            @param b int : value
            @return a // b
        '''
        return a // b

    @RpnOp
    def bin_or(self, a, b):
        ''' @brief Binary or
            @param a int : value
            @param b int : value
            @return a | b
        '''
        return a | b

    @RpnOp
    def bin_xor(self, a, b):
        ''' @brief Binary xor
            @param a int : value
            @param b int : value
            @return a ^ b
        '''
        return a ^ b

    @RpnOp
    def pop(self, a):
        ''' @brief Pops a, head of the stack
            @param a int : value
        '''
        pass

    @RpnOp
    def swp(self, a, b):
        ''' @brief Swap the two values on top of the stack
            @param a int : v1
            @param b int : v2
        '''
        self._push(b)
        self._push(a)
    
    @RpnOp
    def jmp(self, offset):
        ''' @brief Increments IP
            @param offset int : jump offset symbols
        '''
        self.__ip += offset

    @RpnOp
    def jz(self, a, offset):
        ''' @brief Increments IP if a == 0
            @param a int : operand
            @param offset int : jump offset symbols
        '''
        if a == 0:
            self.__ip += offset

    """
    @RpnOp
    def jnz(self, a, offset):
        ''' @brief Increments IP if a != 0
            @param a int : operand
            @param offset int : jump offset symbols
        '''
        if a != 0:
            self.__ip += offset
    """

    @RpnOp
    def jcmp(self, a, b, cnd, offset):
        ''' @brief Increments IP if a == b

            Condition type is encoded on an int : 
            - 0b0000 : je
            - 0b0001 : jne
            - 0b0010 : jle
            - 0b0011 : jl
            - 0b0100 : jg
            - 0b0101 : jge
            - 0b0110 : jne
            - 0b0111 : jmp

            @param a int : operand
            @param b int : operand
            @param cnd int : condition type
            @param offset int : jump offset symbols
        '''
        jmp = False
        if cnd & 1 == 0 and a == b or cnd & 1 and a != b or\
	   cnd & 0b10 and a < b or cnd & 0b100 and a > b:
            self.__ip += offset