import ast
import sys
from helper import *

def convert(py_code: str):
    val_tree = ast.parse(py_code, mode='eval')
    val_gen = Py2EExpressionGenerator()
    val_gen.visit(val_tree)
    print(val_gen.expression)


module_mapping = {
    "cv2": "Evision"
}


class Py2EExpressionGenerator(ast.NodeVisitor):
    def __init__(self):
        self.expression = ''
        self.expression_erlang = ''
        self.skip_this = False
        self.func_arg = False

    def generic_visit(self, node):
        if type(node) is ast.Expression:
            self.visit(node.body)
        elif type(node) is ast.Call:
            fv = node.func.value
            module = fv.id
            func_name = node.func.attr
            if fv.id == 'cv2':
                elixir_module = module_mapping.get(module, module)
                self.expression = f"{elixir_module}.{func_name}("

                args = []

                for arg in node.args:
                    g = Py2EExpressionGenerator()
                    g.func_arg = True
                    g.visit(arg)
                    args.append(g.expression)

                for k in node.keywords:
                    g = Py2EExpressionGenerator()
                    g.func_arg = True
                    g.visit(k.value)
                    args.append(f"{k.arg}: {g.expression}")

                self.expression += ", ".join(args)
                self.expression += ")"
        elif type(node) is ast.Attribute:
            print("attr name:", getattr(node.value, "_fields", []))
            if node.value.id == "cv2":
                self.expression = f"Evision.Constant.cv_{node.attr}()"
            print("node.value.id:", node.value.id)
            print("attr:", node.attr, node.value, node._fields)
        elif type(node) is ast.Constant:
            if self.func_arg:
                if type(node.value) == str:
                    self.expression = f'"{node.value}"'
                else:
                    print("func arg type:", type(node.value))
            else:
                self.expression = f'{node.value}'
                self.expression_erlang = f'{node.value}'
        elif type(node) is ast.UnaryOp:
            op = Py2EExpressionGenerator()
            op.visit(node.op)
            operand = Py2EExpressionGenerator()
            operand.visit(node.operand)
            self.expression = op.expression.format(operand.expression)
            self.expression_erlang = op.expression_erlang.format(operand.expression_erlang)
        elif type(node) is ast.USub:
            self.expression = '-{}'
            self.expression_erlang = '-{}'
        elif type(node) is ast.BinOp:
            op = Py2EExpressionGenerator()
            op.visit(node.op)
            lhs = Py2EExpressionGenerator()
            lhs.visit(node.left)
            rhs = Py2EExpressionGenerator()
            rhs.visit(node.right)
            self.expression = op.expression.format(lhs.expression, rhs.expression)
            self.expression_erlang = op.expression_erlang.format(lhs.expression_erlang, rhs.expression_erlang)
        elif type(node) is ast.LShift:
            self.expression = 'bsl({}, {})'
            self.expression_erlang = '({} bsl {})'
        elif type(node) is ast.RShift:
            self.expression = 'bsr({}, {})'
            self.expression_erlang = '({} bsr {})'
        elif type(node) is ast.Name:
            if node.id[:3] == 'CV_':
                if node.id == 'CV_8U':
                    self.expression = '0'
                    self.expression_erlang = '0'
                elif node.id == 'CV_8S':
                    self.expression = '1'
                    self.expression_erlang = '1'
                elif node.id == 'CV_16U':
                    self.expression = '2'
                    self.expression_erlang = '2'
                elif node.id == 'CV_16S':
                    self.expression = '3'
                    self.expression_erlang = '3'
                elif node.id == 'CV_32S':
                    self.expression = '4'
                    self.expression_erlang = '4'
                elif node.id == 'CV_32F':
                    self.expression = '5'
                    self.expression_erlang = '5'
                elif node.id == 'CV_64F':
                    self.expression = '6'
                    self.expression_erlang = '6'
                elif node.id == 'CV_16F':
                    self.expression = '7'
                    self.expression_erlang = '7'
                elif node.id == 'CV_MAT_CONT_FLAG':
                    self.skip_this = True
                elif node.id == 'CV_SUBMAT_FLAG':
                    self.skip_this = True
                else:
                    print(type(node), node.id, "not handled yet")                    
                    sys.exit(1)
            else:
                if self.func_arg:
                    self.expression = f'cv_{node.id}()'
                    self.expression_erlang = f'cv_{node.id}()'
                else:
                    self.expression = f'cv_{node.id}()'
                    self.expression_erlang = f'cv_{node.id}()'
        elif type(node) is ast.Mult:
            self.expression = '({} * {})'
            self.expression_erlang = '({} * {})'
        elif type(node) is ast.Add:
            self.expression = '({} + {})'
            self.expression_erlang = '({} + {})'
        elif type(node) is ast.Sub:
            self.expression = '({} - {})'
            self.expression_erlang = '({} - {})'
        elif type(node) is ast.BitAnd:
            self.expression = 'band({}, {})'
            self.expression_erlang = '({} band {})'
        elif type(node) is ast.Invert:
            self.expression = 'bnot({})'
            self.expression_erlang = 'bnot({})'
        elif type(node) is ast.BitOr:
            self.expression = 'bor({}, {})'
            self.expression_erlang = '({} bor {})'
        else:
            if sys.version_info.minor < 8:
                if type(node) is ast.Num:
                    self.expression = f'{node.n}'
                    self.expression_erlang = f'{node.n}'
                else:
                    print(type(node), "not implemented yet")
                    sys.exit(1)
            else:
                print(type(node), "not implemented yet")
                sys.exit(1)


if __name__ == '__main__':
    convert("cv2.imread('1.png', flags=cv2.IMREAD_ANY)")