# -*- coding: utf-8 -*-
"""
Implement instructions of the Bitcoin VM.


The MIT License (MIT)

Copyright (c) 2013 by Richard Kiss

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
"""

import binascii
import hashlib

from . import ScriptError

from .opcodes import OPCODE_TO_INT
from .tools import bytes_to_int, int_to_bytes
from ...encoding import hash160, h2b, double_sha256, ripemd160

bytes_from_ints = (lambda x: ''.join(chr(c) for c in x)) if bytes == str else bytes
bytes_to_ints = (lambda x: (ord(c) for c in x)) if bytes == str else lambda x: x

VCH_TRUE = b'\1\1'
VCH_FALSE = b'\0'

do_OP_NOP = do_OP_NOP1 = do_OP_NOP2 = do_OP_NOP3 = do_OP_NOP4 = do_OP_NOP5 = lambda s: None
do_OP_NOP6 = do_OP_NOP7 = do_OP_NOP8 = do_OP_NOP9 = do_OP_NOP10 = lambda s: None

def do_OP_VERIFY(stack):
    pass

def do_OP_RETURN(stack):
    raise ScriptError("OP_RETURN encountered")

def do_OP_2DROP(stack):
    """
    >>> s = [1, 2, 3]
    >>> do_OP_2DROP(s)
    >>> print(s)
    [1]
    """
    stack.pop()
    stack.pop()

def do_OP_2DUP(stack):
    #// (x1 x2 -- x1 x2 x1 x2)
    """
    >>> s = [1, 2]
    >>> do_OP_2DUP(s)
    >>> print(s)
    [1, 2, 1, 2]
    """
    stack.append(stack[-2])
    stack.append(stack[-2])

def do_OP_3DUP(stack):
    #// (x1 x2 x3 -- x1 x2 x3 x1 x2 x3)
    """
    >>> s = [1, 2, 3]
    >>> do_OP_3DUP(s)
    >>> print(s)
    [1, 2, 3, 1, 2, 3]
    """
    stack.append(stack[-3])
    stack.append(stack[-3])
    stack.append(stack[-3])

def do_OP_2OVER(stack):
    #// (x1 x2 x3 x4 -- x1 x2 x3 x4 x1 x2)
    """
    >>> s = [1, 2, 3, 4]
    >>> do_OP_2OVER(s)
    >>> print(s)
    [1, 2, 3, 4, 1, 2]
    """
    stack.append(stack[-4])
    stack.append(stack[-4])

def do_OP_2ROT(stack):
    """
    >>> s = [1, 2, 3, 4, 5, 6]
    >>> do_OP_2ROT(s)
    >>> print(s)
    [3, 4, 5, 6, 1, 2]
    """
    stack.append(stack.pop(-6))
    stack.append(stack.pop(-6))

def do_OP_2SWAP(stack):
    """
    >>> s = [1, 2, 3, 4]
    >>> do_OP_2SWAP(s)
    >>> print(s)
    [3, 4, 1, 2]
    """
    stack.append(stack.pop(-4))
    stack.append(stack.pop(-4))

def do_OP_IFDUP(stack):
    """
    >>> s = [1, 2]
    >>> do_OP_IFDUP(s)
    >>> print(s)
    [1, 2, 2]
    >>> s = [1, 2, 0]
    >>> do_OP_IFDUP(s)
    >>> print(s)
    [1, 2, 0]
    """
    if stack[-1]:
        stack.append(stack[-1])

def do_OP_DEPTH(stack):
    """
    >>> s = [1, 2, 1, 2, 1, 2]
    >>> do_OP_DEPTH(s)
    >>> print(s)
    [1, 2, 1, 2, 1, 2, 6]
    """
    stack.append(len(stack))

def do_OP_DROP(stack):
    """
    >>> s = [1, 2]
    >>> do_OP_DROP(s)
    >>> print(s)
    [1]
    """
    stack.pop()

def do_OP_DUP(stack):
    """
    >>> s = [1, 2]
    >>> do_OP_DUP(s)
    >>> print(s)
    [1, 2, 2]
    """
    stack.append(stack[-1])

def do_OP_NIP(stack):
    """
    >>> s = [1, 2]
    >>> do_OP_NIP(s)
    >>> print(s)
    [2]
    """
    v = stack.pop()
    stack.pop()
    stack.append(v)

def do_OP_OVER(stack):
    """
    >>> s = [1, 2]
    >>> do_OP_OVER(s)
    >>> print(s)
    [1, 2, 1]
    """
    stack.append(stack[-2])

def do_OP_PICK(stack):
    """
    >>> s = ['a', 'b', 'c', 'd', b'\2']
    >>> do_OP_PICK(s)
    >>> print(s)
    ['a', 'b', 'c', 'd', 'b']
    """
    v = bytes_to_int(stack.pop())
    stack.append(stack[-v-1])

def do_OP_ROLL(stack):
    """
    >>> s = ['a', 'b', 'c', 'd', b'\2']
    >>> do_OP_ROLL(s)
    >>> print(s)
    ['a', 'c', 'd', 'b']
    """
    v = bytes_to_int(stack.pop())
    stack.append(stack.pop(-v-1))

def do_OP_ROT(stack):
    """
    >>> s = [1, 2, 3]
    >>> do_OP_ROT(s)
    >>> print(s)
    [2, 3, 1]
    """
    stack.append(stack.pop(-3))

def do_OP_SWAP(stack):
    """
    >>> s = [1, 2, 3]
    >>> do_OP_SWAP(s)
    >>> print(s)
    [1, 3, 2]
    """
    stack.append(stack.pop(-2))

def do_OP_TUCK(stack):
    """
    >>> s = [1, 2, 3]
    >>> do_OP_TUCK(s)
    >>> print(s)
    [1, 3, 2, 3]
    """
    v1 = stack.pop()
    v2 = stack.pop()
    stack.append(v1)
    stack.append(v2)
    stack.append(v1)

def do_OP_CAT(stack):
    """
    >>> s = ["foo", "bar"]
    >>> do_OP_CAT(s)
    >>> print(s)
    ['foobar']
    """
    v1 = stack.pop()
    v2 = stack.pop()
    stack.append(v2 + v1)

def do_OP_SUBSTR(stack):
    """
    >>> s = ['abcdef', b'\3', b'\2']
    >>> do_OP_SUBSTR(s)
    >>> print(s)
    ['de']
    """
    pos = bytes_to_int(stack.pop())
    length = bytes_to_int(stack.pop())
    stack.append(stack.pop()[length:length+pos])

def do_OP_LEFT(stack):
    """
    >>> s = [b'abcdef', b'\\3']
    >>> do_OP_LEFT(s)
    >>> print(len(s)==1 and s[0]==b'abc')
    True
    >>> s = [b'abcdef', b'\\0']
    >>> do_OP_LEFT(s)
    >>> print(len(s) ==1 and s[0]==b'')
    True
    """
    pos = bytes_to_int(stack.pop())
    stack.append(stack.pop()[:pos])

def do_OP_RIGHT(stack):
    """
    >>> s = [b'abcdef', b'\\3']
    >>> do_OP_RIGHT(s)
    >>> print(s==[b'def'])
    True
    >>> s = [b'abcdef', b'\\0']
    >>> do_OP_RIGHT(s)
    >>> print(s==[b''])
    True
    """
    pos = bytes_to_int(stack.pop())
    if pos > 0:
        stack.append(stack.pop()[-pos:])
    else:
        stack.pop()
        stack.append(b'')

def do_OP_SIZE(stack):
    """
    >>> s = [b'abcdef']
    >>> do_OP_SIZE(s)
    >>> print(s == [b'abcdef', b'\x06'])
    True
    >>> s = [b'abcdef'*1000]
    >>> do_OP_SIZE(s)
    >>> print(binascii.hexlify(s[-1]) == b'1770')
    True
    """
    stack.append(int_to_bytes(len(stack[-1])))

def do_OP_INVERT(stack):
    """
    >>> s = [h2b('5dcf39822aebc166')]
    >>> do_OP_INVERT(s)
    >>> print(binascii.hexlify(s[0]) == b'a230c67dd5143e99')
    True
    """
    v = stack.pop()
    # use bytes_from_ints and bytes_to_ints so it works with
    # Python 2.7 and 3.3. Ugh
    stack.append(bytes_from_ints((s^0xff) for s in bytes_to_ints(v)))

def make_same_size(v1, v2):
    larger = max(len(v1), len(v2))
    nulls = b'\0' * larger
    v1 = (v1 + nulls)[:larger]
    v2 = (v2 + nulls)[:larger]
    return v1, v2

def make_bitwise_bin_op(binop):
    """
    >>> s = [h2b('5dcf39832aebc166'), h2b('ff00f086') ]
    >>> do_OP_AND(s)
    >>> print(binascii.hexlify(s[0]) == b'5d00308200000000')
    True
    >>> s = [h2b('5dcf39832aebc166'), h2b('ff00f086') ]
    >>> do_OP_OR(s)
    >>> print(binascii.hexlify(s[0]) == b'ffcff9872aebc166')
    True
    >>> s = [h2b('5dcf39832aebc166'), h2b('ff00f086') ]
    >>> do_OP_XOR(s)
    >>> print(binascii.hexlify(s[0]) == b'a2cfc9052aebc166')
    True
    >>> s = []
    """
    def f(stack):
        v1 = stack.pop()
        v2 = stack.pop()
        v1, v2 = make_same_size(v1, v2)
        stack.append(bytes_from_ints(binop(c1, c2) for c1, c2 in zip(bytes_to_ints(v1), bytes_to_ints(v2))))
    return f

do_OP_AND = make_bitwise_bin_op(lambda x,y: x & y)
do_OP_OR = make_bitwise_bin_op(lambda x,y: x | y)
do_OP_XOR = make_bitwise_bin_op(lambda x,y: x ^ y)

def make_bool(v):
    if v: return VCH_TRUE
    return VCH_FALSE

def do_OP_EQUAL(stack):
    """
    >>> s = [b'string1', b'string1']
    >>> do_OP_EQUAL(s)
    >>> print(s == [VCH_TRUE])
    True
    >>> s = [b'string1', b'string2']
    >>> do_OP_EQUAL(s)
    >>> print(s == [VCH_FALSE])
    True
    """
    v1 = stack.pop()
    v2 = stack.pop()
    stack.append(make_bool(v1 == v2))

do_OP_EQUALVERIFY = lambda s: do_OP_EQUAL(s)

def make_bin_op(binop):
    def f(stack):
        v1 = bytes_to_int(stack.pop())
        v2 = bytes_to_int(stack.pop())
        stack.append(int_to_bytes(binop(v2, v1)))
    return f

do_OP_ADD = make_bin_op(lambda x,y: x+y)
do_OP_SUB = make_bin_op(lambda x,y: x-y)
do_OP_MUL = make_bin_op(lambda x,y: x*y)
do_OP_DIV = make_bin_op(lambda x,y: x//y)
do_OP_MOD = make_bin_op(lambda x,y: x%y)
do_OP_LSHIFT = make_bin_op(lambda x,y: x<<y)
do_OP_RSHIFT = make_bin_op(lambda x,y: x>>y)
do_OP_BOOLAND = make_bin_op(lambda x,y: x and y)
do_OP_BOOLOR = make_bin_op(lambda x,y: x or y)
do_OP_NUMEQUAL = make_bin_op(lambda x,y: x==y)
do_OP_NUMEQUALVERIFY = make_bin_op(lambda x,y: x==y)
do_OP_NUMNOTEQUAL = make_bin_op(lambda x,y: x!=y)
do_OP_LESSTHAN = make_bin_op(lambda x,y: x<y)
do_OP_GREATERTHAN = make_bin_op(lambda x,y: x>y)
do_OP_LESSTHANOREQUAL = make_bin_op(lambda x,y: x<=y)
do_OP_GREATERTHANOREQUAL = make_bin_op(lambda x,y: x>=y)
do_OP_MIN = make_bin_op(min)
do_OP_MAX = make_bin_op(max)

def do_OP_WITHIN(stack):
    """
    >>> s = [b'c', b'b', b'a']
    >>> do_OP_WITHIN(s)
    >>> print(s == [VCH_TRUE])
    True
    >>> s = [b'b', b'c', b'a']
    >>> do_OP_WITHIN(s)
    >>> print(s == [VCH_FALSE])
    True
    """
    v3 = stack.pop()
    v2 = stack.pop()
    v1 = stack.pop()
    ok = (v3 <= v2 <= v1)
    stack.append(make_bool(ok))

def do_OP_RIPEMD160(stack):
    """
    >>> s = [b'foo']
    >>> do_OP_RIPEMD160(s)
    >>> print(s == [bytearray([66, 207, 162, 17, 1, 142, 164, 146, 253, 238, 69, 172, 99, 123, 121, 114, 160, 173, 104, 115])])
    True
    """
    stack.append(ripemd160(stack.pop()).digest())

def do_OP_SHA1(stack):
    """
    >>> s = [b'foo']
    >>> do_OP_SHA1(s)
    >>> print(s == [bytearray([11, 238, 199, 181, 234, 63, 15, 219, 201, 93, 13, 212, 127, 60, 91, 194, 117, 218, 138, 51])])
    True
    """
    stack.append(hashlib.sha1(stack.pop()).digest())

def do_OP_SHA256(stack):
    """
    >>> s = [b'foo']
    >>> do_OP_SHA256(s)
    >>> print(s == [bytearray([44, 38, 180, 107, 104, 255, 198, 143, 249, 155, 69, 60, 29, 48, 65, 52, 19, 66, 45, 112, 100, 131, 191, 160, 249, 138, 94, 136, 98, 102, 231, 174])])
    True
    """
    stack.append(hashlib.sha256(stack.pop()).digest())

def do_OP_HASH160(stack):
    """
    >>> s = [b'foo']
    >>> do_OP_HASH160(s)
    >>> print(s == [bytearray([225, 207, 124, 129, 3, 71, 107, 109, 127, 233, 228, 151, 154, 161, 14, 124, 83, 31, 207, 66])])
    True
    """
    stack.append(hash160(stack.pop()))

def do_OP_HASH256(stack):
    """
    >>> s = [b'foo']
    >>> do_OP_HASH256(s)
    >>> print(s == [bytearray([199, 173, 232, 143, 199, 162, 20, 152, 166, 165, 229, 195, 133, 225, 246, 139, 237, 130, 43, 114, 170, 99, 196, 169, 164, 138, 2, 194, 70, 110, 226, 158])])
    True
    """
    stack.append(double_sha256(stack.pop()))

def make_unary_num_op(unary_f):
    def f(stack):
        stack.append(int_to_bytes(unary_f(bytes_to_int(stack.pop()))))
    return f

do_OP_1ADD = make_unary_num_op(lambda x: x+1)
do_OP_1SUB = make_unary_num_op(lambda x: x-1)
do_OP_2MUL = make_unary_num_op(lambda x: x<<1)
do_OP_2DIV = make_unary_num_op(lambda x: x>>1)
do_OP_NEGATE = make_unary_num_op(lambda x: -x)
do_OP_ABS = make_unary_num_op(lambda x: abs(x))
do_OP_NOT = make_unary_num_op(lambda x: make_bool(x == 0))
do_OP_0NOTEQUAL = make_unary_num_op(lambda x: make_bool(x != 0))

def build_ops_lookup():
    d = {}
    the_globals = globals()
    for opcode_name, opcode_int in OPCODE_TO_INT.items():
        do_f_name = "do_%s" % opcode_name
        if do_f_name in the_globals:
            d[opcode_int] = the_globals[do_f_name]
    return d

MICROCODE_LOOKUP = build_ops_lookup()

if __name__ == "__main__":
    import doctest
    doctest.testmod()
