#include "ctx.h"

#include <ivy/lang/ast.h>

bool parse_if(struct ivy_parser *parser, struct ivy_ast_node **out)
{
	if (!parse_keyword(parser, IVY_KW_IF)) {
		parse_trace(parser, "expected `if` keyword");
		return false;
	}

	struct ivy_ast_cond_group_node *cond_group
		= create_node(IVY_AST_COND_GROUP);
	struct ivy_ast_cond_node *cond = create_node(IVY_AST_COND);

	if (!parse_expr(parser, EXPR_PARSE_STOP_LEFT_BRACKET, &cond->n_cond)) {
		parse_trace(parser, "invalid if predicate");
		return false;
	}

	if (!parse_block(parser, &cond->n_body)) {
		parse_trace(parser, "invalid if body");
		return false;
	}

	fx_queue_push_back(&cond_group->n_branches, &cond->n_base.n_entry);

	bool ok = true;
	while (1) {
		struct ivy_ast_node *branch_pred = NULL;
		struct ivy_ast_node *branch_block = NULL;
		if (parse_keyword(parser, IVY_KW_ELIF)) {
			if (!parse_expr(
				    parser, EXPR_PARSE_STOP_LEFT_BRACKET,
				    &branch_pred)) {
				parse_trace(
					parser,
					"invalid elif branch predicate");
				ok = false;
				break;
			}
		} else if (!parse_keyword(parser, IVY_KW_ELSE)) {
			break;
		}

		if (!parse_block(parser, &branch_block)) {
			parse_trace(parser, "invalid branch body");
			ok = false;
			break;
		}

		struct ivy_ast_cond_node *cond = create_node(IVY_AST_COND);
		cond->n_cond = branch_pred;
		cond->n_body = branch_block;
		fx_queue_push_back(&cond_group->n_branches, &cond->n_base.n_entry);

		if (!branch_pred) {
			break;
		}
	}

	*out = generic_node(cond_group);
	return true;
}

bool parse_if_inline(
	struct ivy_parser *parser, struct ivy_ast_node *body,
	struct ivy_ast_node **out)
{
	if (!parse_keyword(parser, IVY_KW_IF)) {
		parse_trace(parser, "expected `if` keyword");
		return false;
	}

	struct ivy_ast_cond_group_node *cond_group
		= create_node(IVY_AST_COND_GROUP);
	struct ivy_ast_cond_node *cond = create_node(IVY_AST_COND);
	cond->n_body = body;

	if (!parse_expr(parser, EXPR_PARSE_NORMAL, &cond->n_cond)) {
		parse_trace(parser, "invalid if predicate");
		return false;
	}

	fx_queue_push_back(&cond_group->n_branches, &cond->n_base.n_entry);

	if (parse_keyword(parser, IVY_KW_ELSE)) {
		struct ivy_ast_cond_node *cond = create_node(IVY_AST_COND);
		if (!parse_expr(parser, EXPR_PARSE_NORMAL, &cond->n_body)) {
			parse_trace(parser, "invalid else body");
			return false;
		}

		fx_queue_push_back(&cond_group->n_branches, &cond->n_base.n_entry);
	}

	*out = generic_node(cond_group);
	return true;
}