from typing import *
from lark import Transformer, Tree, Token

T = TypeVar("T")

class Decl:
	name: str
class Iface(Decl):
	def __init__(self, name: str):
		self.name = name
class IfaceField: pass

class IfaceRef: pass
class Expr: pass

class NodeRef: pass
class NodeRefByName(NodeRef):
	def __init__(self, name: str):
		self.name = name
	def __repr__(self) -> str: return f"NodeRefByName({self.name})"

class Sym: pass
class SymRename(Sym):
	def __init__(self, name: str, node_ref: NodeRef):
		self.name = name
		self.node_ref = node_ref
	def __repr__(self) -> str: return f"SymRename({self.name} : {self.node_ref})"
class Equation:
	def __init__(self, lhs: Expr, rhs: Expr):
		self.lhs = lhs
		self.rhs = rhs

class Variant:
	def __init__(self, prod: List[Sym], equations: List[Equation]):
		self.prod = prod
		self.equations = equations
	def __repr__(self) -> str: return f"Variant({self.prod}, {self.equations})"

class Node(Decl):
	def __init__(self, name: str, ifaces: List[IfaceRef], variants: List[Variant]):
		self.name = name
		self.ifaces = ifaces
		self.variants = variants

class ExprDot(Expr):
	def __init__(self, left: Expr, right: Expr):
		self.left = left
		self.right = right
	def __repr__(self) -> str: return f"{self.left}.{self.right}"
class ExprAdd(Expr):
	def __init__(self, left: Expr, right: Expr):
		self.left = left
		self.right = right
	def __repr__(self) -> str: return f"{self.left} + {self.right}"
class ExprMul(Expr):
	def __init__(self, left: Expr, right: Expr):
		self.left = left
		self.right = right
	def __repr__(self) -> str: return f"{self.left} * {self.right}"
class ExprCall(Expr):
	def __init__(self, func: Expr, args: List[Expr]):
		self.func = func
		self.args = args
	def __repr__(self) -> str: return f"{self.func}({self.args})"
class ExprName(Expr):
	def __init__(self, name: str):
		self.name = name
	def __repr__(self) -> str: return f"{self.name}"

class Parser(Transformer[List[Decl]]):
	def program(self, items: List[Decl]) -> List[Decl]: return items

	# interfaces
	def iface(self, items: List[Any]) -> Iface:
		[name, fields] = items
		return Iface(name)
	def iface_field(self, items: List[str]) -> IfaceField:
		[name, ty] = items
		return IfaceField()
	def iface_ref(self, items: List[str]) -> str: return items[0]
	def iface_refs(self, items: List[IfaceRef]) -> List[IfaceRef]: return items

	# nodes
	def node(self, items: List[Any]) -> Node:
		[name, ifaces, variants] = items
		return Node(name, ifaces, variants)
	def node_ref_name(self, items: List[str]) -> NodeRefByName: return NodeRefByName(items[0])

	# variants
	def variants(self, items: List[Variant]) -> List[Variant]: return items
	def variant(self, items: List[Any]) -> Variant:
		[prod, equations] = items
		return Variant(prod, equations)
	def prod(self, items: List[Sym]) -> List[Sym]: return items

	def sym_rename(self, items: List[Any]) -> Sym: return SymRename(items[0], items[1])

	# equations
	def equations(self, items: List[Equation]) -> List[Equation]: return items
	def equation_(self, items: List[Equation]) -> Equation: return items[0]
	def equation(self, items: List[Expr]) -> Equation: return Equation(items[0], items[1])

	# expr
	def expr_dot(self, items: List[Expr]) -> Expr:
		[left, right] = items
		return ExprDot(left, right)
	def expr_add(self, items: List[Expr]) -> Expr:
		[left, right] = items
		return ExprAdd(left, right)
	def expr_mul(self, items: List[Expr]) -> Expr:
		[left, right] = items
		return ExprMul(left, right)
	def expr_call(self, items: List[Expr]) -> Expr:
		[func, args] = items
		return ExprMul(func, args)

	def sep_trail(self, items: List[Tree]) -> List[T]:
		return list(map(lambda it: cast(T, it), items))

	def ident(self, items: List[Token]) -> str: return cast(str, items[0].value)