from generators.generator import Generator
from ground_ast import *
from error import traceback

class X86_64Generator(Generator):
	def __init__(self, ast, code, output_path):
		super().__init__(ast, code, output_path)
		self.stack_size = 0

	def init(self):
		self.lines.append("global _start\n\n")
		self.lines.append("_start:\n\t")

		# generate code
		self.generate()
		self.write()

	def push(self, reg: str):
		self.lines.append("push " + reg + "\n\t")
		self.stack_size += 1

	def pop(self, reg: str):
		self.lines.append("pop " + reg + "\n\t")
		self.stack_size -= 1

	def get_variable(self, var_name: str, reg: str, float: bool = False):
		var = self.variables.get(var_name, None)
		var_pos = self.get_var_pos(var_name)
		try:
			#print(var["type"])
			if var["type"] == FloatNode or float:
				conversion = {
					"rax": "xmm0",
					"rbx": "xmm1",
					"rdi": "xmm0"
					# ...
				}

				self.lines.append(f"movsd {conversion[reg]}, [rsp + {var_pos}]\n\t")
				self.lines.append("add rsp, 8\n\t")
				#self.stack_size -= 1
			elif var["type"] == IntNode:
				self.push(
					f"QWORD [rsp + {var_pos}]"
				)
				self.pop(reg)
			
		except TypeError: # variable doesnt exist
			traceback(self.code, "NameError", f"\"{var_name}\" is not defined.")
		return var["type"]

	def get_var_pos(self, var_name: str):
		return (self.stack_size - self.variables.get(var_name)['stack_loc'] - 1) * 8

	def create_variable(self, var_name: str, starting_value, var_type: Any = None):
		if var_type == None:
			var_type = type(starting_value)

		stack_location = self.stack_size

		if type(starting_value) == IntNode:
			self.lines.append(f"mov rax, {starting_value.value}\n\t")
			self.push("rax")
		elif type(starting_value) == VarRefNode:
			var_type = self.get_variable(starting_value.var_name, "rax")

			if var_type == FloatNode:
				self.lines.append("sub rsp, 8\n\t")
				self.lines.append("movsd [rsp], xmm0\n\t")
			else:
				self.push("rax")
		elif type(starting_value) == FloatNode:
			name = self.add_constant(starting_value.value)
			self.lines.append("sub rsp, 8\n\t") # make space on the stack
			self.lines.append(f"movsd xmm0, {name}\n\t")
			self.lines.append("movsd [rsp], xmm0\n\t")
			self.stack_size += 1

		elif type(starting_value) == str:
			if starting_value.startswith("xmm"): # floating point stuff
				self.lines.append("sub rsp, 8\n\t") # make space
				self.lines.append(f"movsd [rsp], {starting_value}\n\t")
				self.stack_size += 1
			else:
				self.push(starting_value)
		self.variables[var_name] = {"stack_loc": stack_location, "type": var_type}

	def change_variable(self, var_name: str, new_value):
		var_pos = self.get_var_pos(var_name)

		if type(new_value) == IntNode: # we're changing a variable to a number
			self.lines.append(f"mov QWORD [rsp + {var_pos}], {new_value.value}\n\t")

		elif type(new_value) == VarRefNode: # we're changing a variable to the value of another variable
			self.get_variable(new_value.var_name, "rax")
			self.lines.append(f"mov QWORD [rsp + {var_pos}], rax\n\t")

		elif type(new_value) == str: # we're changing a variable to the value of a register
			self.lines.append(f"mov QWORD [rsp + {var_pos}], {new_value}\n\t")

	def generate_InstructionNode(self, node: InstructionNode):
		if node.instruction == "end":
			if len(node.arguments) == 0: # example: "end"
				traceback(self.code, "TypeError", "end expects atleast 1 argument.")
			elif len(node.arguments) > 1: # example: "end 1 1"
				traceback(self.code, "TypeError", "end expects only 1 argument.")
			if not type(node.arguments[0]) in [IntNode, VarRefNode]: # example: "end true"
				traceback(self.code, "TypeError", f"end expects an integer, not {node.arguments[0]}")

			self.lines.append("mov rax, 60\n\t")
			if isinstance(node.arguments[0], IntNode):
				self.lines.append("mov rdi, " + str(node.arguments[0].value) + "\n\t")
			elif isinstance(node.arguments[0], VarRefNode): 
				var_type = self.get_variable(node.arguments[0].var_name, "rdi")
				if var_type == FloatNode:
					self.lines.append("cvttsd2si rdi, xmm0\n\t")
				else:
					if var_type != IntNode:
						traceback(self.code, "TypeError", f"end expects an integer, not \"{var_type}\"")
				#self.lines.append("mov rdi, " + str(self.get_variable(node.arguments[0].var_name)) + "\n\t")
			self.lines.append("syscall\n\t")

		elif node.instruction == "set":
			if len(node.arguments) < 2: # example: "set" or "set &hi"
				traceback(self.code, "TypeError", "set expects atleast 2 arguments.")
			elif len(node.arguments) > 2: # example: "set &hi 0 123"
				traceback(self.code, "TypeError", "set expects only 2 arguments.")
			if not isinstance(node.arguments[0], VarPointerNode):
				traceback(self.code, "TypeError", f"the first argument of set should be a variable pointer, not \"{node.arguments[0]}\"")
			if type(node.arguments[1]) not in [IntNode, VarRefNode, FloatNode]:
				traceback(self.code, "TypeError", f"variables can't be of type \"{type(node.arguments[1])}\"")

			variable_exists = self.variables.get(node.arguments[0].var_name, None) != None

			if not variable_exists: # create a new variable
				self.create_variable(node.arguments[0].var_name, node.arguments[1])
			else: # modify the existing one
				self.change_variable(node.arguments[0].var_name, node.arguments[1])

		elif node.instruction == "add":
			if len(node.arguments) < 3: # example: "add" or "add 1" or "add 1 2"
				traceback(self.code, "TypeError", "add expects atleast 3 arguments.")
			elif len(node.arguments) > 3: # example: "add 1 2 3 4"
				traceback(self.code, "TypeError", "add expects only 3 arguments.")
			elif type(node.arguments[2]) != VarPointerNode:
				traceback(self.code, "TypeError", f"the destination of the add command must be a variable pointer, not \"{node.arguments[2]}\"")
			
			# bro this entire god damn instruction is just error handling 😔
			number1_type = None	
			number2_type = None
			arg2 = "rbx"
			if isinstance(node.arguments[0], VarRefNode):
				number1_type = self.get_variable(node.arguments[0].var_name, "rax")
			elif isinstance(node.arguments[0], FloatNode) or isinstance(node.arguments[1], FloatNode):
				number1_type = FloatNode
				constant_name = self.add_constant(node.arguments[0].value)
				self.lines.append(f"movsd xmm0, {constant_name}\n\t")
			elif isinstance(node.arguments[0], IntNode):
				number1_type = IntNode
				#arg1 = node.arguments[0].value
				self.lines.append(f"mov rax, {node.arguments[0].value}\n\t")
			else:
				traceback(self.code, "TypeError", f"expected a variable reference or number for argument 1 of add, got {node.arguments[0]}")

			if isinstance(node.arguments[1], VarRefNode):
				number2_type = self.get_variable(node.arguments[1].var_name, "rbx")
			elif number1_type == FloatNode or isinstance(node.arguments[1], FloatNode):
				number2_type = FloatNode
				constant_name = self.add_constant(node.arguments[1].value)
				self.lines.append(f"movsd xmm1, {constant_name}\n\t")
			elif isinstance(node.arguments[1], IntNode):
				number2_type = IntNode
				arg2 = node.arguments[1].value
				#self.lines.append(f"mov rbx, {node.arguments[1].value}\n\t")
			else:
				traceback(self.code, "TypeError", f"expected a variable reference or number for argument 2 of add, got {node.arguments[1]}")

			# TODO: numbers can be added to numbers, but numbers cant be added to strings. but strings can be added to strings, etc...
			if number1_type not in [IntNode, FloatNode] or number2_type not in [IntNode, FloatNode]:
				traceback(self.code, "TypeError", f"Unsupported operation \"add\" for \"{node.arguments[0]}\" and \"{node.arguments[1]}\".")

			if number1_type == IntNode and number2_type == IntNode:
				self.lines.append(f"add rax, {arg2}\n\t")
			else:
				self.lines.append(f"addsd xmm0, xmm1\n\t")

			is_integer = number1_type == IntNode and number2_type == IntNode
			starting_reg = "rax" if is_integer else "xmm0"

			if self.variables.get(node.arguments[2].var_name, None) == None: # we need to create a variable for the destination
				self.create_variable(node.arguments[2].var_name, starting_reg, IntNode if is_integer else FloatNode)
			else:
				self.change_variable(node.arguments[2].var_name, starting_reg)

		elif node.instruction == "subtract":
			if len(node.arguments) < 3: # example: "subtract" or "subtract 1" or "subtract 1 2"
				traceback(self.code, "TypeError", "subtract expects atleast 3 arguments.")
			elif len(node.arguments) > 3: # example: "subtract 1 2 3 4"
				traceback(self.code, "TypeError", "subtract expects only 3 arguments.")
			elif type(node.arguments[2]) != VarPointerNode:
				traceback(self.code, "TypeError", f"the destination of the subtract command must be a variable pointer, not \"{node.arguments[2]}\"")
			
			# bro this entire god damn instruction is just error handling 😔
			number1_type = None	
			number2_type = None
			arg2 = "rbx"
			if isinstance(node.arguments[0], VarRefNode):
				number1_type = self.get_variable(node.arguments[0].var_name, "rax", isinstance(node.arguments[1], FloatNode))
			elif isinstance(node.arguments[0], FloatNode) or isinstance(node.arguments[1], FloatNode):
				number1_type = FloatNode
				constant_name = self.add_constant(node.arguments[0].value)
				self.lines.append(f"movsd xmm0, {constant_name}\n\t")
			elif isinstance(node.arguments[0], IntNode):
				number1_type = IntNode
				#arg1 = node.arguments[0].value
				self.lines.append(f"mov rax, {node.arguments[0].value}\n\t")
			else:
				traceback(self.code, "TypeError", f"expected a variable reference or number for argument 1 of subtract, got {node.arguments[0]}")

			if isinstance(node.arguments[1], VarRefNode):
				number2_type = self.get_variable(node.arguments[1].var_name, "rbx", number1_type == FloatNode)
			elif number1_type == FloatNode or isinstance(node.arguments[1], FloatNode):
				number2_type = FloatNode
				constant_name = self.add_constant(node.arguments[1].value)
				self.lines.append(f"movsd xmm1, {constant_name}\n\t")
			elif isinstance(node.arguments[1], IntNode):
				number2_type = IntNode
				arg2 = node.arguments[1].value
				#self.lines.append(f"mov rbx, {node.arguments[1].value}\n\t")
			else:
				traceback(self.code, "TypeError", f"expected a variable reference or number for argument 2 of subtract, got {node.arguments[1]}")

			# TODO: numbers can be added to numbers, but numbers cant be added to strings. but strings can be added to strings, etc...
			if number1_type not in [IntNode, FloatNode] or number2_type not in [IntNode, FloatNode]:
				traceback(self.code, "TypeError", f"Unsupported operation \"subtract\" for \"{node.arguments[0]}\" and \"{node.arguments[1]}\".")

			if number1_type == IntNode and number2_type == IntNode:
				self.lines.append(f"sub rax, {arg2}\n\t")
			else:
				self.lines.append(f"subsd xmm0, xmm1\n\t")

			is_integer = number1_type == IntNode and number2_type == IntNode
			starting_reg = "rax" if is_integer else "xmm0"

			if self.variables.get(node.arguments[2].var_name, None) == None: # we need to create a variable for the destination
				self.create_variable(node.arguments[2].var_name, starting_reg, IntNode if is_integer else FloatNode)
			else:
				self.change_variable(node.arguments[2].var_name, starting_reg)

		else:
			self.lines.append("; FUCK\n\t")
			#raise NotImplementedError(f"A generate method hasn't been made for the \"{node.instruction}\" instruction.")

	def write(self):

		with open(self.output_path + ".asm", "w") as f:
			f.write("section .data\n")
			for name, value in self.constants.items():
				f.write("." + name + ": ")
				value_type = type(value)
				if value_type == str:
					f.write(f"db \"{value}\", 0")
				elif value_type == float or value_type == int:
					f.write(f"dq {float(value)}")
				f.write("\n")
			f.write("\nsection .text\n")
			f.writelines(self.lines)