"""
AST (abstract syntax tree) nodes for the c3 language.
The tree is build by the parser.
Then it is checked
Finally code is generated from it.
"""

from ppci import SourceLocation


class Node:
    pass


# Modules
class Package(Node):
    def __init__(self, name, loc):
        self.name = name
        self.loc = loc
        self.declarations = []
        self.imports = []

    def __repr__(self):
        return 'MODULE {}'.format(self.name)


class Designator(Node):
    def __init__(self, tname, loc):
        self.tname = tname
        self.loc = loc

    def __repr__(self):
        return 'DESIGNATOR {}'.format(self.tname)


class ImportDesignator(Designator):
    def __init__(self, tname, vname, loc):
        super().__init__(tname, loc)
        self.vname = vname

    def __repr__(self):
        return 'IMPORT DESIGNATOR {}:{}'.format(self.tname, self.vname)


"""
Type classes

types must be comparable.

There are the following types:
- base type -> basic type (built in)
- struct type -> a composite type that contains a list of named fields
            of other types
- function type
"""


class Type(Node):
    pass


class BaseType(Type):
    def __init__(self, name):
        self.name = name

    def __repr__(self):
        return '{}'.format(self.name)


class FunctionType(Type):
    def __init__(self, parametertypes, returntype):
        self.parametertypes = parametertypes
        self.returntype = returntype

    def __repr__(self):
        params = ', '.join([str(v) for v in self.parametertypes])
        return '{1} f({0})'.format(params, self.returntype)


class PointerType(Type):
    """ A type that points to data of some other type """
    def __init__(self, ptype):
        assert isinstance(ptype, Type) or isinstance(ptype, Designator)
        self.ptype = ptype

    def __repr__(self):
        return '({}*)'.format(self.ptype)


class StructField:
    def __init__(self, name, typ):
        self.name = name
        self.typ = typ
        self.offset = 0


class StructureType(Type):
    def __init__(self, mems):
        self.mems = mems
        for mem in mems:
            assert type(mem) is StructField
            assert type(mem.name) is str

    def hasField(self, name):
        for mem in self.mems:
            if name == mem.name:
                return True
        return False

    def fieldType(self, name):
        return self.findField(name).typ

    def fieldOffset(self, name):
        return self.findField(name).offset

    def findField(self, name):
        for mem in self.mems:
            if name == mem.name:
                return mem
        raise KeyError(name)

    def __repr__(self):
        return 'STRUCT'


class DefinedType(Type):
    """ A named type indicating another type """
    def __init__(self, name, typ, loc):
        assert isinstance(name, str)
        self.name = name
        self.typ = typ
        self.loc = loc

    def __repr__(self):
        return 'Named type {0} of type {1}'.format(self.name, self.typ)


# Variables, parameters, local variables, constants:
class Symbol(Node):
    def __init__(self, name):
        self.name = name
        self.refs = []

    def addRef(self, r):
        self.refs.append(r)

    @property
    def References(self):
        return self.refs


class Constant(Symbol):
    def __init__(self, name, typ, value):
        super().__init__(name)
        self.typ = typ
        self.value = value

    def __repr__(self):
        return 'CONSTANT {0} = {1}'.format(self.name, self.value)


class Variable(Symbol):
    def __init__(self, name, typ):
        super().__init__(name)
        self.typ = typ
        self.ival = None
        self.isLocal = False
        self.isReadOnly = False
        self.isParameter = False

    def __repr__(self):
        return 'Var {} [{}]'.format(self.name, self.typ)


class LocalVariable(Variable):
    def __init__(self, name, typ):
        super().__init__(name, typ)
        self.isLocal = True


class FormalParameter(Variable):
    def __init__(self, name, typ):
        super().__init__(name, typ)
        self.isParameter = True


# Procedure types
class Function(Symbol):
    """ Actual implementation of a function """
    def __init__(self, name, loc):
        super().__init__(name)
        self.loc = loc
        self.declarations = []

    def __repr__(self):
        return 'Func {}'.format(self.name)


# Operations / Expressions:
class Expression(Node):
    def __init__(self, loc):
        self.loc = loc


class Deref(Expression):
    def __init__(self, ptr, loc):
        super().__init__(loc)
        assert isinstance(ptr, Expression)
        self.ptr = ptr

    def __repr__(self):
        return 'DEREF {}'.format(self.ptr)


class TypeCast(Expression):
    def __init__(self, to_type, x, loc):
        super().__init__(loc)
        self.to_type = to_type
        self.a = x

    def __repr__(self):
        return 'TYPECAST {}'.format(self.to_type)


class FieldRef(Expression):
    def __init__(self, base, field, loc):
        super().__init__(loc)
        assert isinstance(base, Expression)
        assert isinstance(field, str)
        self.base = base
        self.field = field

    def __repr__(self):
        return 'FIELD {}.{}'.format(self.base, self.field)


class Unop(Expression):
    def __init__(self, op, a, loc):
        super().__init__(loc)
        assert isinstance(a, Expression)
        assert isinstance(op, str)
        self.a = a
        self.op = op

    def __repr__(self):
        return 'UNOP {}'.format(self.op)


class Binop(Expression):
    def __init__(self, a, op, b, loc):
        super().__init__(loc)
        assert isinstance(a, Expression), type(a)
        assert isinstance(b, Expression)
        assert isinstance(op, str)
        self.a = a
        self.b = b
        self.op = op   # Operation: '+', '-', '*', '/', 'mod'

    def __repr__(self):
        return 'BINOP {}'.format(self.op)


class VariableUse(Expression):
    def __init__(self, target, loc):
        super().__init__(loc)
        self.target = target

    def __repr__(self):
        return 'VAR USE {}'.format(self.target)


class Literal(Expression):
    def __init__(self, val, loc):
        super().__init__(loc)
        self.val = val

    def __repr__(self):
        return 'LITERAL {}'.format(self.val)


class FunctionCall(Expression):
    def __init__(self, proc, args, loc):
        super().__init__(loc)
        self.proc = proc
        self.args = args

    def __repr__(self):
        return 'CALL {0} '.format(self.proc)


# Statements
class Statement(Node):
    def __init__(self, loc):
        self.loc = loc


class CompoundStatement(Statement):
    def __init__(self, statements):
        super().__init__(None)
        self.statements = statements
        for s in self.statements:
            assert isinstance(s, Statement)

    def __repr__(self):
        return 'COMPOUND STATEMENT'


class ReturnStatement(Statement):
    def __init__(self, expr, loc):
        super().__init__(loc)
        self.expr = expr

    def __repr__(self):
        return 'RETURN STATEMENT'


class Assignment(Statement):
    def __init__(self, lval, rval, loc):
        super().__init__(loc)
        assert isinstance(lval, Node)
        assert isinstance(rval, Node)
        self.lval = lval
        self.rval = rval

    def __repr__(self):
        return 'ASSIGNMENT'


class ExpressionStatement(Statement):
    def __init__(self, ex, loc):
        super().__init__(loc)
        self.ex = ex

    def __repr__(self):
        return 'Epression'


class IfStatement(Statement):
    def __init__(self, condition, truestatement, falsestatement, loc):
        super().__init__(loc)
        self.condition = condition
        self.truestatement = truestatement
        self.falsestatement = falsestatement

    def __repr__(self):
        return 'IF-statement'


class WhileStatement(Statement):
    def __init__(self, condition, statement, loc):
        super().__init__(loc)
        self.condition = condition
        self.statement = statement

    def __repr__(self):
        return 'WHILE-statement'