#include "ctx.h"
#include "expr/expr.h"
#include "iterate.h"
#include "node.h"

#include <ivy/lang/ast.h>

struct global_parser_state {
	struct parser_state s_base;
	unsigned int s_prev_token;
};

static void init_state(struct ivy_parser *ctx, struct parser_state *sp, uintptr_t arg)
{
	struct global_parser_state *state = (struct global_parser_state *)sp;
	state->s_prev_token = IVY_KW_GLOBAL;
}

struct token_parse_result parse_ident(struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct global_parser_state *state
		= parser_get_state(ctx, struct global_parser_state);
	if (state->s_prev_token != IVY_KW_GLOBAL) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	struct expr_parser_state *ident_parse
		= (struct expr_parser_state *)parser_push_state(
			ctx, IVY_AST_EXPR, 0);
	expr_add_terminator(ident_parse, IVY_SYM_EQUAL);
	expr_add_terminator(ident_parse, IVY_SYM_DOT);
	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
}

struct token_parse_result parse_left_paren(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct global_parser_state *state
		= parser_get_state(ctx, struct global_parser_state);

	if (state->s_prev_token != IVY_KW_GLOBAL) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	struct expr_parser_state *tuple_ident_parse
		= (struct expr_parser_state *)parser_push_state(
			ctx, IVY_AST_EXPR, 0);
	expr_add_terminator(tuple_ident_parse, IVY_SYM_EQUAL);
	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
}

struct token_parse_result parse_equal(struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct global_parser_state *state
		= parser_get_state(ctx, struct global_parser_state);
	struct ivy_ast_global_node *global
		= (struct ivy_ast_global_node *)state->s_base.s_node;
	if (!global->n_left) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	state->s_prev_token = IVY_SYM_EQUAL;

	struct expr_parser_state *val_parse
		= (struct expr_parser_state *)parser_push_state(
			ctx, IVY_AST_EXPR, 0);
	expr_add_terminator(val_parse, IVY_SYM_DOT);
	return PARSE_RESULT(IVY_OK, 0);
}

struct token_parse_result parse_dot(struct ivy_parser *ctx, struct ivy_token *tok)
{
	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
	return PARSE_RESULT(IVY_OK, 0);
}

static enum ivy_status add_child(
	struct parser_state *parent, struct ivy_ast_node *child)
{
	struct global_parser_state *state = (struct global_parser_state *)parent;
	struct ivy_ast_global_node *global
		= (struct ivy_ast_global_node *)parent->s_node;

	switch (state->s_prev_token) {
	case IVY_KW_GLOBAL:
		if (global->n_left) {
			return IVY_ERR_BAD_SYNTAX;
		}

		global->n_left = child;
		break;
	case IVY_SYM_EQUAL:
		if (global->n_val) {
			return IVY_ERR_BAD_SYNTAX;
		}

		global->n_val = child;
		break;
	default:
		return IVY_ERR_BAD_SYNTAX;
	}

	return IVY_OK;
}

static void collect_children(
	struct ivy_ast_node *node, struct ivy_ast_node_iterator *iterator)
{
	struct ivy_ast_global_node *global = (struct ivy_ast_global_node *)node;

	if (global->n_left) {
		ast_node_iterator_enqueue_node(iterator, node, global->n_left);
	}

	if (global->n_val) {
		ast_node_iterator_enqueue_node(iterator, node, global->n_val);
	}
}

struct ast_node_type global_node_ops = {
	.n_add_child = add_child,
	.n_collect_children = collect_children,
	.n_state_size = sizeof(struct global_parser_state),
	.n_node_size = sizeof(struct ivy_ast_global_node),
	.n_init_state = init_state,
	.n_token_parsers = {
		TOK_PARSER(IDENT, parse_ident),
	},
	.n_symbol_parsers = {
		SYM_PARSER(LEFT_PAREN, parse_left_paren),
		SYM_PARSER(EQUAL, parse_equal),
		SYM_PARSER(DOT, parse_dot),
	},
};