#include"parse.h"

#include<assert.h>
#include<stdlib.h>
#include<string.h>
#include"utils.h"
#include"vartable.h"
#include"reporting.h"
#include<stdint.h>
#include<signal.h>
#include"x86.h"

#ifndef __GNUC__
static inline int __builtin_clzl(unsigned long x) {
	unsigned long n = 32;
	unsigned long y;

	y = x >>16; if (y != 0) { n = n -16; x = y; }
	y = x >> 8; if (y != 0) { n = n - 8; x = y; }
	y = x >> 4; if (y != 0) { n = n - 4; x = y; }
	y = x >> 2; if (y != 0) { n = n - 2; x = y; }
	y = x >> 1; if (y != 0) return n - 2;
	
	return n - x;
}
#endif

typedef struct {
	Token *tokens;
	intmax_t i;
	
	VarTable *scope;
	
	// Used to coalesce all scopes into one after parsing, to perform global register allocation
	ASTChunk *topLevel;
	
	// Used by pushstat to add statements
	ASTChunk *currentChunk;
	
	// Used to place guard variable uses after loops to stop reg allocation from fucking up
	VarTable *loopScope;
	size_t guardedVarCount;
	ASTExprVar **guardedVars;
} Parser;

static Token get(Parser *P) {
	if(P->tokens[P->i].type == TOKEN_EOF) {
		return P->tokens[P->i];
	} else {
		return P->tokens[P->i++];
	}
}

static Token expect(Parser *P, TokenKind t) {
	Token tok = get(P);

	if(tok.type != t) {
		stahp(tok.row, tok.column, "Expected %s, got %s.", TOKEN_NAMES[t], TOKEN_NAMES[tok.type]);
	}
	
	return tok;
}

static Token peek(Parser *P, int depth) {
	int j = 0;
	for(; j < depth; j++) {
		if(P->tokens[P->i + j].type == TOKEN_EOF) {
			break;
		}
	}
	return P->tokens[P->i + j];
}

static int maybe(Parser *P, TokenKind t) {
	if(peek(P, 0).type == t) {
		get(P);
		return 1;
	}
	return 0;
}

static void pushstat(Parser *P, void *a) {
	if(P->currentChunk->statementFirst) {
		P->currentChunk->statementLast->statement.next = a;
		P->currentChunk->statementLast = a;
	} else {
		P->currentChunk->statementFirst = P->currentChunk->statementLast = a;
	}
}

static ASTExprPrimitive *parse_prim(Parser *P) {
	ASTExprPrimitive *ret = malloc(sizeof(*ret));
	ret->nodeKind = AST_EXPR_PRIMITIVE;
	
	Token tok = get(P);
	
	const char *str = tok.content;
	int base = 10;
	if(strchr(str, 'r')) {
		base = strtol(str, (char**) &str, 10);
		str++; /* Go past the r. */
	}
	
	ret->val = strtol(str, NULL, base);
	
	// Smallest integer type to store number
	char buf[8];
	snprintf(buf, sizeof(buf), "s%i", ret->val ? (64 - __builtin_clzl(ret->val - 1)) : 1);
	ret->type = (Type*) primitive_parse(buf);
	
	return ret;
}

/*static void newusedef(Parser *P, VarTableEntry *v, AST *expr) {
	ReachingDefs *defs = v->data.var.reachingDefs;
	
	while(defs) {
		for(size_t i = 0; i < defs->defCount; i++) {
			P->udsToAdd = realloc(P->udsToAdd, sizeof(*P->udsToAdd) * (++P->udsToAddCount));
			P->udsToAdd[P->udsToAddCount - 1].ud.def = defs->defs[i];
			P->udsToAdd[P->udsToAddCount - 1].ud.use = expr;
			P->udsToAdd[P->udsToAddCount - 1].ud.stmt = NULL; // set by pushstmt
			P->udsToAdd[P->udsToAddCount - 1].ud.next = NULL;
			P->udsToAdd[P->udsToAddCount - 1].to = v;
		}
		
		if(defs->excludeParent) {
			break;
		}
		
		defs = defs->parent;
	}
}*/

static AST *exprvar(Parser *P, VarTableEntry *v) {
	AST *a = malloc(sizeof(ASTExprVar));
	a->nodeKind = AST_EXPR_VAR;
	a->exprVar.type = v->type;
	a->exprVar.thing = v;
	
	if(P->loopScope) {
		// XXX: O(n)!!!!!!!!!
		
		int inloop = 0;
		for(VarTable *vt = v->owner; vt; vt = vt->parent) {
			if(vt->parent == P->loopScope) {
				inloop = 1;
				break;
			}
		}
		
		if(!inloop) {
			int alreadyAdded = 0;
			for(size_t i = 0; i < P->guardedVarCount; i++) {
				if(P->guardedVars[i]->thing == v) {
					alreadyAdded = 1;
					break;
				}
			}
			
			if(!alreadyAdded) {
				ASTExprVar *ev = malloc(sizeof(*ev));
				memcpy(ev, a, sizeof(*ev));
				
				P->guardedVars = realloc(P->guardedVars, sizeof(*P->guardedVars) * (P->guardedVarCount + 1));
				P->guardedVars[P->guardedVarCount++] = ev;
			}
		}
	}
	
	return a;
}

AST *nct_cast_expr(AST *what, Type *to) {
	if(what == NULL) return NULL;	
	
	/* Only exists at parse-time, hence not part of type system and is handled separately */
	if(what->nodeKind == AST_EXPR_STRING_LITERAL) {
		if(to->type == TYPE_TYPE_ARRAY && type_equal(primitive_parse("u8"), to->array.of) && to->array.length == what->exprStrLit.length) {
			ASTExprArray *ret = malloc(sizeof(*ret));
			ret->nodeKind = AST_EXPR_ARRAY;
			ret->items = malloc(sizeof(*ret->items) * to->array.length);
			ret->type = to;
			
			for(int i = 0; i < to->array.length; i++) {
				uint8_t bajt = what->exprStrLit.data[i];
				
				ASTExprPrimitive *item = malloc(sizeof(*item));
				item->nodeKind = AST_EXPR_PRIMITIVE;
				item->type = to->array.of;
				item->val = bajt;
				
				ret->items[i] = (AST*) item;
			}
			
			return (AST*) ret;
		} else if(to->type == TYPE_TYPE_PRIMITIVE) {
			if(to->primitive.width != what->exprStrLit.length * 8) {
				stahp(0, 0, "Size mismatch between string literal and target type");
			}
			
			ASTExprPrimitive *ret = malloc(sizeof(*ret));
			ret->nodeKind = AST_EXPR_PRIMITIVE;
			ret->type = to;
			memcpy(&ret->val, what->exprStrLit.data, sizeof(ret->val));
			return (AST*) ret;
		} else abort();
	}
	
	if(type_equal(what->expression.type, to)) return what;
	
	if(!type_is_castable(what->expression.type, to)) {
		return NULL;
	}
	
	if(what->nodeKind == AST_EXPR_PRIMITIVE && (to->type == TYPE_TYPE_PRIMITIVE || to->type == TYPE_TYPE_POINTER)) {
		ASTExprPrimitive *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_EXPR_PRIMITIVE;
		ret->type = to;
		
		if(to->type == TYPE_TYPE_PRIMITIVE) {
			ret->val = what->exprPrim.val & ((1UL << to->primitive.width) - 1);
		} else {
			ret->val = what->exprPrim.val & ((1UL << (8 * type_size(to))) - 1);
		}
		
		return (AST*) ret;
	} else {
		ASTExprCast *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_EXPR_CAST;
		ret->type = to;
		ret->what = what;
		ret->to = to;
		return (AST*) ret;
	}
	
	abort();
}

ASTChunk *nct_parse_chunk(Parser*, int, int);
Type *nct_parse_typename(Parser *P);

AST *nct_parse_expression(Parser *P, int lOP) {
	if(lOP == 0) {
		// Test if this is an anonymous function 
		Type *ft = nct_parse_typename(P);
		if(ft) {
			assert(ft->type == TYPE_TYPE_FUNCTION);
			
			ASTExprFunc *e = malloc(sizeof(*e));
			e->nodeKind = AST_EXPR_FUNC;
			e->type = ft;
			
			maybe(P, TOKEN_SQUIGGLY_L);
			
			e->chunk = (AST*) nct_parse_chunk(P, 1, 0);
			
			maybe(P, TOKEN_SQUIGGLY_R);
			
			return (AST*) e;
		}
	}
	
	if(lOP == 5) {
		if(peek(P, 0).type == TOKEN_NUMBER) {
			return (AST*) parse_prim(P);
		} else if(peek(P, 0).type == TOKEN_IDENTIFIER) {
			if(!strcmp(peek(P, 0).content, "@stack")) {
				get(P);
				
				ASTExprStackPointer *ret = malloc(sizeof(*ret));
				ret->nodeKind = AST_EXPR_STACK_POINTER;
				ret->type = primitive_parse("u32");
				return (AST*) ret;
			}
			
			return exprvar(P, vartable_find(P->scope, get(P).content));
		} else if(peek(P, 0).type == TOKEN_STRING) {
			ASTExprStringLiteral *ret = malloc(sizeof(*ret));
			ret->nodeKind = AST_EXPR_STRING_LITERAL;
			
			Token tok = get(P);
			
			ret->type = &TYPE_ERROR;
			ret->data = tok.content;
			ret->length = tok.length;
			
			return (AST*) ret;
		} else if(maybe(P, TOKEN_PAREN_L)) {
			AST *e = nct_parse_expression(P, 0);
			expect(P, TOKEN_PAREN_R);
			return e;
		}
	} else if(lOP == 4) {
		if(maybe(P, TOKEN_STAR)) {
			ASTExprUnaryOp *astop = malloc(sizeof(*astop));
			astop->nodeKind = AST_EXPR_UNARY_OP;
			astop->operator = UNOP_DEREF;
			astop->operand = nct_parse_expression(P, lOP); /* Not +1! */
			astop->type = astop->operand->expression.type->pointer.of;
			
			return (AST*) astop;
		} else if(maybe(P, TOKEN_AMPERSAND)) {
			ASTExprUnaryOp *astop = malloc(sizeof(*astop));
			astop->nodeKind = AST_EXPR_UNARY_OP;
			astop->operator = UNOP_REF;
			astop->operand = nct_parse_expression(P, lOP);
			astop->type = type_pointer_wrap(astop->operand->expression.type);
			
			return (AST*) astop;
		} else if(maybe(P, TOKEN_MINUS)) {
			AST *operand = nct_parse_expression(P, lOP);
			
			if(operand->nodeKind == AST_EXPR_PRIMITIVE) {
				operand->exprPrim.val *= -1;
				return operand;
			} else {
				ASTExprUnaryOp *astop = malloc(sizeof(*astop));
				astop->nodeKind = AST_EXPR_UNARY_OP;
				astop->operator = UNOP_NEGATE;
				astop->operand = operand;
				astop->type = operand->expression.type;

				return (AST*) astop;
			}
		} else if(maybe(P, TOKEN_TILDE)) {
			AST *child = nct_parse_expression(P, lOP);

			if(child->nodeKind == AST_EXPR_PRIMITIVE) {
				child->exprPrim.val = ~child->exprPrim.val;
				return child;
			} else {
				ASTExprUnaryOp *astop = malloc(sizeof(*astop));
				astop->nodeKind = AST_EXPR_UNARY_OP;
				astop->operator = UNOP_BITWISE_NOT;
				astop->operand = child;
				astop->type = child->expression.type;

				return (AST *) astop;
			}
		} else return nct_parse_expression(P, lOP + 1);
	} else if(lOP == 3) {
		AST *ret = nct_parse_expression(P, lOP + 1);

		while(peek(P, 0).type == TOKEN_PAREN_L || peek(P, 0).type == TOKEN_SQUAREN_L) {
			if(maybe(P, TOKEN_PAREN_L)) {
				if(ret->expression.type->type != TYPE_TYPE_FUNCTION) {
					stahp(P->tokens[P->i].row, P->tokens[P->i].column, "Only function types may be called.");
				}
				
				VarTableEntry *tempo = calloc(1, sizeof(*tempo));
				tempo->kind = VARTABLEENTRY_VAR;
				tempo->type = ret->expression.type->function.ret;
				tempo->data.var.name = "$temp";
				tempo->data.var.color = COLOR_EAX;
				
				P->topLevel->vars = realloc(P->topLevel->vars, sizeof(*P->topLevel->vars) * (++P->topLevel->varCount));
				P->topLevel->vars[P->topLevel->varCount - 1] = tempo;
				
				ASTExprCall *call = malloc(sizeof(*call));
				call->nodeKind = AST_EXPR_CALL;
				call->type = ret->expression.type->function.ret;
				call->what = ret;
				call->args = NULL;
				
				int argCount = 0;
				
				if(!maybe(P, TOKEN_PAREN_R)) {
					while(peek(P, 0).type != TOKEN_PAREN_R && peek(P, 0).type != TOKEN_COMMA) {
						call->args = realloc(call->args, (argCount + 1) * sizeof(AST*));
						call->args[argCount] = nct_parse_expression(P, 0);
						
						argCount++;
						
						if(maybe(P, TOKEN_PAREN_R)) {
							break;
						} else expect(P, TOKEN_COMMA);
					}
				}
				
				ASTStmtAssign *assign = calloc(1, sizeof(*assign));
				assign->nodeKind = AST_STMT_ASSIGN;
				assign->what = exprvar(P, tempo);
				assign->to = call;
				
				pushstat(P, assign);
				
				ret = exprvar(P, tempo);
				/* TODO: Check argument count. */
			} else if(maybe(P, TOKEN_SQUAREN_L)) {
				ASTExprUnaryOp *ref = malloc(sizeof(*ref));
				ref->nodeKind = AST_EXPR_UNARY_OP;
				ref->operator = UNOP_REF;
				ref->operand = ret;
				ref->type = type_pointer_wrap(ret->expression.type->array.of);
				
				ASTExprBinaryOp *child = malloc(sizeof(*child));
				child->nodeKind = AST_EXPR_BINARY_OP;
				child->operands[0] = (AST*) ref;
				child->operands[1] = nct_parse_expression(P, 0);
				child->operator = BINOP_ADD;
				child->type = ref->type;
				
				int typesize = type_size(ret->expression.type->array.of);
				if(typesize != 1) {
					ASTExprPrimitive *scale = malloc(sizeof(*scale));
					scale->nodeKind = AST_EXPR_PRIMITIVE;
					scale->type = primitive_parse("u16");
					scale->val = typesize;
					
					ASTExprBinaryOp *mul = malloc(sizeof(*mul));
					mul->nodeKind = AST_EXPR_BINARY_OP;
					mul->operator = BINOP_MUL;
					mul->operands[0] = (AST*) scale;
					mul->operands[1] = child->operands[1];
					
					child->operands[1] = (AST*) mul;
				}
				
				ASTExprUnaryOp *unop = malloc(sizeof(*unop));
				unop->nodeKind = AST_EXPR_UNARY_OP;
				unop->type = ret->expression.type->array.of;
				unop->operator = UNOP_DEREF;
				unop->operand = (AST*) child;
				
				ret = (AST*) unop;
				
				expect(P, TOKEN_SQUAREN_R);
			} else abort();
		}
		
		return ret;
	} else if(lOP == 2) {
		AST *ret = nct_parse_expression(P, lOP + 1);
		
		if(peek(P, 0).type == TOKEN_STAR || peek(P, 0).type == TOKEN_SLASH) {
			while(1) {
				BinaryOp op;
				if(maybe(P, TOKEN_STAR)) op = BINOP_MUL;
				else if(maybe(P, TOKEN_SLASH)) op = BINOP_DIV;
				else break;
				
				ASTExprBinaryOp *astop = malloc(sizeof(*astop));
				astop->nodeKind = AST_EXPR_BINARY_OP;
				astop->type = ret->expression.type;
				astop->operator = op;
				astop->operands[0] = ret;
				
				AST *operand = nct_parse_expression(P, lOP + 1);
				
				if(operand->expression.type->type != TYPE_TYPE_PRIMITIVE) {
					stahp(P->tokens[P->i].row, P->tokens[P->i].column, "Invalid combination of operator and operand types.");
  				}
  				
  				astop->operands[1] = operand;
  				
  				if(!astop->type) {
					astop->type = operand->expression.type;
				} else {
					if(type_size(operand->expression.type) > type_size(astop->type)) {
						astop->type = operand->expression.type;
					}
				}
				
				ret = (AST*) astop;
			}
		}
		
		return ret;
	} else if(lOP == 1) {
		AST *ret = nct_parse_expression(P, lOP + 1);
		
		if(
			peek(P, 0).type == TOKEN_PLUS
			|| peek(P, 0).type == TOKEN_MINUS
			|| peek(P, 0).type == TOKEN_AMPERSAND
			|| peek(P, 0).type == TOKEN_VERTICAL_BAR
			|| peek(P, 0).type == TOKEN_CARET
		) {
			while(1) {
				BinaryOp op;
				if(maybe(P, TOKEN_PLUS)) op = BINOP_ADD;
				else if(maybe(P, TOKEN_MINUS)) op = BINOP_SUB;
				else if(maybe(P, TOKEN_AMPERSAND)) op = BINOP_BITWISE_AND;
				else if(maybe(P, TOKEN_VERTICAL_BAR)) op = BINOP_BITWISE_OR;
				else if(maybe(P, TOKEN_CARET)) op = BINOP_BITWISE_XOR;
				else break;
				
				ASTExprBinaryOp *astop = malloc(sizeof(*astop));
				astop->nodeKind = AST_EXPR_BINARY_OP;
				astop->type = ret->expression.type;
				astop->operator = op;
				astop->operands[0] = ret;
				
				ASTExpr *operand = &(astop->operands[1] = nct_parse_expression(P, lOP + 1))->expression;
				
				if(!type_is_number(astop->operands[0]->expression.type)
					|| !type_is_number(astop->operands[1]->expression.type)) {
					
					stahp(P->tokens[P->i].row, P->tokens[P->i].column, "Attempt to perform arithmetic on non-number types.");
				}
				
				if(type_size(astop->operands[0]->expression.type) < type_size(astop->operands[1]->expression.type)) {
					astop->operands[0] = nct_cast_expr(astop->operands[0], astop->operands[1]->expression.type);
				}
				
				if(type_size(astop->operands[1]->expression.type) < type_size(astop->operands[0]->expression.type)) {
					astop->operands[1] = nct_cast_expr(astop->operands[1], astop->operands[0]->expression.type);
				}
				
  				if(!astop->type) {
					astop->type = operand->type;
				} else {
					if(type_size(operand->type) > type_size(astop->type)) {
						astop->type = operand->type;
					}
				}
				
				ret = (AST*) astop;
			}
		}
		
		return ret;
	} else if(lOP == 0) {
		AST *ret = nct_parse_expression(P, lOP + 1);
		
		if(peek(P, 0).type == TOKEN_DOUBLE_EQUALS || peek(P, 0).type == TOKEN_EXCLAMATION_EQUALS) {
			while(1) {
				BinaryOp op;
				if(maybe(P, TOKEN_DOUBLE_EQUALS)) op = BINOP_EQUAL;
				else if(maybe(P, TOKEN_EXCLAMATION_EQUALS)) op = BINOP_NEQUAL;
				else break;
				
				ASTExprBinaryOp *astop = malloc(sizeof(*astop));
				astop->nodeKind = AST_EXPR_BINARY_OP;
				astop->type = NULL;
				astop->operator = op;
				astop->operands[0] = ret;
				
				ASTExpr *operand = &(astop->operands[1] = nct_parse_expression(P, lOP + 1))->expression;
				
				if(operand->type->type != TYPE_TYPE_PRIMITIVE) {
					stahp(P->tokens[P->i].row, P->tokens[P->i].column, "Invalid combination of operator and operand types.");
  				}
  				
  				if(!astop->type) {
					astop->type = operand->type;
				} else {
					if(type_size(operand->type) > type_size(astop->type)) {
						astop->type = operand->type;
					}
				}
				
				ret = (AST*) astop;
			}
		}
		
		ret = ast_expression_optimize(ret);
		
		return ret;
	}
#ifdef DEBUG
	else abort();
#endif
	
	return NULL;
}

/* Since this function backtracks, don't use aborting functions like expect. */
Type *nct_parse_typename(Parser *P) {
	int oldIdx = P->i;
	
	if(peek(P, 0).type != TOKEN_IDENTIFIER) {
		goto backtrack;
	}
	
	Type *ret = (Type*) primitive_parse(expect(P, TOKEN_IDENTIFIER).content);
	
	if(!ret) {
		goto backtrack;
	}
	
	while(peek(P, 0).type == TOKEN_PAREN_L || peek(P, 0).type == TOKEN_STAR || peek(P, 0).type == TOKEN_SQUAREN_L) {
		if(maybe(P, TOKEN_STAR)) {
			TypePointer *ptr = malloc(sizeof(*ptr));
			ptr->type = TYPE_TYPE_POINTER;
			ptr->of = ret;
			
			ret = (Type*) ptr;
		} else if(maybe(P, TOKEN_PAREN_L)) {
			TypeFunction *fun = malloc(sizeof(*fun));
			fun->type = TYPE_TYPE_FUNCTION;
			fun->ret = ret;
			fun->argCount = 0;
			fun->args = malloc(0);
			
			if(!maybe(P, TOKEN_PAREN_R)) {
				while(1) {
					fun->argCount++;
					fun->args = realloc(fun->args, sizeof(Type*) * fun->argCount);
					if((fun->args[fun->argCount - 1] = nct_parse_typename(P)) == NULL) {
						free(fun);
						goto backtrack;
					}
					
					if(maybe(P, TOKEN_PAREN_R)) {
						break;
					} else expect(P, TOKEN_COMMA);
				}
			}
			
			ret = (Type*) fun;
		} else if(maybe(P, TOKEN_SQUAREN_L)) {
			TypeArray *arr = malloc(sizeof(*arr));
			arr->type = TYPE_TYPE_ARRAY;
			arr->of = ret;
			
			if(peek(P, 0).type == TOKEN_NUMBER) {
				ASTExprPrimitive *prim = parse_prim(P);
				
				arr->length = prim->val;
				
				free(prim);
			} else if(maybe(P, TOKEN_QUESTION_MARK)) {
				arr->length = 0;
			} else {
				//stahp(P->tokens[P->i].row, P->tokens[P->i].column, "Array size must be either constant or '?'.");
				goto backtrack;
			}
			
			expect(P, TOKEN_SQUAREN_R);
			
			ret = (Type*) arr;
		}
	}
	
	return ret;
backtrack:
	P->i = oldIdx;
	return NULL;
}

/* Potentially backtracking. Returns NULL upon failure. */
static AST *parse_declaration(Parser *P) {
	int oldIdx = P->i;
	
	int isLocal = maybe(P, TOKEN_LOCAL);
	int isExternal = 0;
	if(!isLocal) {
		isExternal = maybe(P, TOKEN_EXTERN);
	}
	
	Type *type = nct_parse_typename(P);
	
	if(!type) goto backtrack;
	if(peek(P, 0).type != TOKEN_IDENTIFIER) goto backtrack;
	
	Token name = expect(P, TOKEN_IDENTIFIER);
	
	VarTableEntry *entry;
	if(peek(P, 0).type == TOKEN_COLON && (entry = vartable_get(P->scope, name.content))) {
		/* Forward declared. */
	} else {
		entry = calloc(sizeof(*entry), 1);
		entry->type = type;
	}
	
	AST *ret = NULL;
	
	if(maybe(P, TOKEN_EQUALS) || (peek(P, 0).type == TOKEN_SEMICOLON && !isExternal && !isLocal)) {
		/*if(isExternal || isLocal) {
			fputs("'local' and 'extern' keywords are to be used for symbol declaration only.\n", stderr);
			abort();
			return NULL;
		}*/
		
		entry->kind = VARTABLEENTRY_VAR;
		entry->data.var.priority = 1;
		entry->data.var.color = -1;
		
		ASTStmtAssign *assign = malloc(sizeof(*assign));
		assign->nodeKind = AST_STMT_ASSIGN;
		assign->next = NULL;
		
		//entry->data.var.reachingDefs = reachingdefs_push(NULL);
		//reachingdefs_set(entry->data.var.reachingDefs, (AST*) assign);
		
		assign->what = exprvar(P, entry);
		assign->to = peek(P, 0).type == TOKEN_SEMICOLON ? NULL : nct_parse_expression(P, 0);
		
		ret = (AST*) assign;
		
	} else {
		ASTStmtDecl *decl = malloc(sizeof(*ret));
		decl->nodeKind = AST_STMT_DECL;
		decl->thing = entry;
		decl->next = NULL;
		
		if(maybe(P, TOKEN_COLON)) {
			if(isExternal) {
				fputs("External symbols may not be defined.\n", stderr);
				abort();
				return NULL;
			}
			
			entry->kind = VARTABLEENTRY_SYMBOL;
			entry->data.symbol.isLocal = isLocal;
			entry->data.symbol.isExternal = isExternal;
			entry->data.symbol.name = name.content;
			
			decl->expression = nct_cast_expr(nct_parse_expression(P, 0), type);
			
			if(decl->expression) {
				//if(ret->expression->expression.constantType == EXPRESSION_NOT_CONSTANT) {
				//	stahp(1, 4142, "Symbol declaration may contain constant expressions only.");
				//}
			}
		} else if(isExternal) {
			entry->kind = VARTABLEENTRY_SYMBOL;
			entry->data.symbol.isLocal = isLocal;
			entry->data.symbol.isExternal = isExternal;
			entry->data.symbol.name = name.content;
		} else {
			abort();
		}
		
		ret = (AST*) decl;
	}
	
	vartable_set(P->scope, name.content, entry);
	
	expect(P, TOKEN_SEMICOLON);
	
	return ret;
backtrack:
	P->i = oldIdx;
	return NULL;
}

void nct_parse_statement(Parser *P) {
	if(maybe(P, TOKEN_IF)) {
		expect(P, TOKEN_PAREN_L);
		AST *e = nct_parse_expression(P, 0);
		expect(P, TOKEN_PAREN_R);
		
		ASTStmtIf *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_STMT_IF;
		ret->next = NULL;
		
		ret->expression = e;
		
		pushstat(P, ret);
		
		expect(P, TOKEN_SQUIGGLY_L);
		ret->then = (AST*) nct_parse_chunk(P, 0, 0);
		expect(P, TOKEN_SQUIGGLY_R);
		return;
	} else if(maybe(P, TOKEN_LOOP)) {
		ASTStmtLoop *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_STMT_LOOP;
		ret->next = NULL;
		
		int isFirstLoop = P->loopScope == NULL;
		
		if(isFirstLoop) {
			P->loopScope = P->scope;
		}
		
		expect(P, TOKEN_SQUIGGLY_L);
		ret->body = (AST*) nct_parse_chunk(P, 0, 1);
		expect(P, TOKEN_SQUIGGLY_R);
		
		pushstat(P, ret);
		
		if(isFirstLoop) {
			P->loopScope = NULL;
			
			for(size_t i = 0; i < P->guardedVarCount; i++) {
				ASTExprVar *ev = P->guardedVars[i];
				
				AST *es = calloc(1, sizeof(ASTStmtExpr));
				es->nodeKind = AST_STMT_EXPR;
				es->stmtExpr.expr = (AST*) ev;
				
				pushstat(P, es);
			}
			
			P->guardedVarCount = 0;
			free(P->guardedVars);
			P->guardedVars = NULL;
		}
		
		return;
	} else if(maybe(P, TOKEN_BREAK)) {
		ASTStmtBreak *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_STMT_BREAK;
		ret->next = NULL;
		
		expect(P, TOKEN_SEMICOLON);
		
		pushstat(P, ret);
		
		return;
	} else if(maybe(P, TOKEN_CONTINUE)) {
		ASTStmtContinue *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_STMT_CONTINUE;
		ret->next = NULL;
		
		expect(P, TOKEN_SEMICOLON);
		
		pushstat(P, ret);
		
		return;
	} else if(peek(P, 0).type == TOKEN_IDENTIFIER) {
		if(!strcmp(peek(P, 0).content, "@align")) {
			ASTStmtExtAlign *ret = malloc(sizeof(*ret));
			ret->nodeKind = AST_STMT_EXT_ALIGN;
			ret->next = NULL;
			
			get(P);
			
			expect(P, TOKEN_PAREN_L);
			ASTExprPrimitive *val = parse_prim(P);
			ret->val = val->val;
			free(val);
			expect(P, TOKEN_PAREN_R);
			
			expect(P, TOKEN_SEMICOLON);
			
			pushstat(P, ret);
			return;
		} else if(!strcmp(peek(P, 0).content, "@org")) {
			ASTStmtExtOrg *ret = malloc(sizeof(*ret));
			ret->nodeKind = AST_STMT_EXT_ORG;
			ret->next = NULL;
			
			get(P);
			
			expect(P, TOKEN_PAREN_L);
			ASTExprPrimitive *val = parse_prim(P);
			ret->val = val->val;
			free(val);
			expect(P, TOKEN_PAREN_R);
			
			expect(P, TOKEN_SEMICOLON);
			
			pushstat(P, ret);
			return;
		} else if(!strcmp(peek(P, 0).content, "@section")) {
			ASTStmtExtSection *ret = malloc(sizeof(*ret));
			ret->nodeKind = AST_STMT_EXT_SECTION;
			ret->next = NULL;
			
			get(P);
			
			expect(P, TOKEN_PAREN_L);
			ret->name = expect(P, TOKEN_STRING);
			expect(P, TOKEN_PAREN_R);
			
			expect(P, TOKEN_SEMICOLON);
			
			pushstat(P, ret);
			return;
		}
	}
	
	{
		AST *decl = parse_declaration(P);
		if(decl) {
			pushstat(P, decl);
			return;
		}
	}
	
	AST *e = nct_parse_expression(P, 0);
	
	if(maybe(P, TOKEN_EQUALS)) {
		ASTStmtAssign *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_STMT_ASSIGN;
		ret->next = NULL;
 		ret->what = e;
		ret->to = nct_cast_expr(nct_parse_expression(P, 0), ret->what->expression.type);
		
		//if(ret->what->nodeKind == AST_EXPR_VAR) {
		//	reachingdefs_set(ret->what->exprVar.thing->data.var.reachingDefs, (AST*) ret);
		//}
		
		expect(P, TOKEN_SEMICOLON);
		
		pushstat(P, ret);
		return;
	} else {
		ASTStmtExpr *ret = malloc(sizeof(*ret));
		ret->nodeKind = AST_STMT_EXPR;
		ret->next = NULL;
		ret->expr = e;
		
		expect(P, TOKEN_SEMICOLON);
		
		pushstat(P, ret);
		return;
	}
}

ASTChunk *nct_parse_chunk(Parser *P, int isTopLevel, int varPrioritize) {
	AST *ret = calloc(1, sizeof(ASTChunk));
	ret->nodeKind = AST_CHUNK;
	ret->chunk.statementFirst = ret->chunk.statementLast = NULL;
	ret->chunk.varCount = 0;
	ret->chunk.vars = NULL;
	ret->chunk.stackReservation = 0;
	
	AST *oldChunk = (AST*) P->currentChunk;
	P->currentChunk = &ret->chunk;
	
	P->scope = vartable_new(P->scope);
	
	ASTChunk *oldTopLevel = P->topLevel;
	if(isTopLevel) {
		P->topLevel = &ret->chunk;
	}
	
	//vartable_new_reachingdefs_for_all_vars(P->scope);
	
	/* Find all symbol names and struct types ahead of time. Searches for colons as those can only mean symbol declarations */
	
	{
		size_t oldIdx = P->i;
		
		while(1) {
			TokenKind k = get(P).type;
			if(k == (isTopLevel ? TOKEN_EOF : TOKEN_SQUIGGLY_R)) {
				break;
			} else if(k == TOKEN_SQUIGGLY_L) { /* Don't enter deeper scopes. */
				int depth = 0;
				
				while(1) {
					switch(get(P).type) {
					case TOKEN_SQUIGGLY_L: depth++; break;
					case TOKEN_SQUIGGLY_R: if(depth-- == 0) goto stomp; break;
					default:;
					}
				}
				stomp:;
			} else if(k == TOKEN_COLON) {
				/* Move back to beginning of declaration. */
				do {
					P->i--;
				} while(P->i >= 0 && P->tokens[P->i].type != TOKEN_SEMICOLON && P->tokens[P->i].type != TOKEN_SQUIGGLY_R);
				P->i++;
				
				AST *d = parse_declaration(P);
				if(!d) abort();
				
				free(d); /* We don't need it. */
			}
		}
		P->i = oldIdx;
	}
	
	/* Now actual parsing. */
	
	while(peek(P, 0).type != TOKEN_EOF && peek(P, 0).type != TOKEN_SQUIGGLY_R) {
		nct_parse_statement(P);
	}
	
	//vartable_coalesce_reachingdefs_for_all_vars(P->scope);
	
	size_t nonSymbols = 0;
	for(size_t i = 0; i < P->scope->count; i++) {
		if(P->scope->data[i]->kind == VARTABLEENTRY_VAR) {
			nonSymbols++;
			
			if(varPrioritize) {
				P->scope->data[i]->data.var.priority++;
			}
		}
	}
	P->topLevel->vars = realloc(P->topLevel->vars, sizeof(*P->topLevel->vars) * (P->topLevel->varCount + nonSymbols));
	for(size_t i = 0; i < P->scope->count; i++) {
		if(P->scope->data[i]->kind == VARTABLEENTRY_VAR) {
			P->topLevel->vars[P->topLevel->varCount++] = P->scope->data[i];
			//P->scope->data[i]->owner = P->topLevel; // not sure why this line ever existed, it makes no sense
		}
	}
	
	P->scope = P->scope->parent;
	
	P->currentChunk = oldChunk;
	
	if(isTopLevel) {
		P->topLevel = oldTopLevel;
	}
	
	return &ret->chunk;
}

AST *nct_parse(Token *tokens) {
	Parser P;
	memset(&P, 0, sizeof(P));
	P.tokens = tokens;
	return (AST*) nct_parse_chunk(&P, 1, 0);
}