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

#include <blue/object/string.h>
#include <ivy/lang/lex.h>
#include <stdio.h>

struct tuple_parser_state {
	struct parser_state s_base;

	struct ivy_ast_node *s_prev_node;
	unsigned int s_prev;

	b_queue s_items;
};

static void finalise_tuple(struct tuple_parser_state *state)
{
	struct ivy_ast_tuple_node *tuple = (struct ivy_ast_tuple_node *)state->s_base.s_node;

	tuple->n_members = state->s_items;
	state->s_items = B_QUEUE_INIT;
}

struct token_parse_result parse_comma(struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct tuple_parser_state *state = parser_get_state(ctx, struct tuple_parser_state);
	if (state->s_prev != IVY_SYM_LEFT_PAREN && state->s_prev != IVY_SYM_COMMA) {
		/* token not expected at this time. */
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	if (!state->s_prev_node) {
		/* empty tuple member */
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	b_queue_push_back(&state->s_items, &state->s_prev_node->n_entry);
	state->s_prev_node = NULL;
	state->s_prev = IVY_SYM_COMMA;

	struct expr_parser_state *expr = (struct expr_parser_state *)parser_push_state(ctx, IVY_AST_EXPR, 0);
	expr_add_terminator(expr, IVY_SYM_COMMA);
	expr_add_terminator(expr, IVY_SYM_RIGHT_PAREN);
	expr->s_subexpr_depth = 1;

	return PARSE_RESULT(IVY_OK, 0);
}

struct token_parse_result parse_right_paren(struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct tuple_parser_state *state = parser_get_state(ctx, struct tuple_parser_state);
	if (state->s_prev != IVY_SYM_COMMA) {
		/* token not expected at this time. */
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	if (!state->s_prev_node) {
		/* empty tuple member */
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	b_queue_push_back(&state->s_items, &state->s_prev_node->n_entry);
	state->s_prev_node = NULL;
	state->s_prev = IVY_SYM_RIGHT_PAREN;

	finalise_tuple(state);
	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 tuple_parser_state *state
		= (struct tuple_parser_state *)parent;

	if (state->s_prev_node) {
		return IVY_ERR_BAD_SYNTAX;
	}

	state->s_prev_node = child;
	return IVY_OK;
}

static void init_state(struct ivy_parser *ctx, struct parser_state *sp, uintptr_t arg)
{
	struct tuple_parser_state *state = (struct tuple_parser_state *)sp;
	state->s_prev = IVY_SYM_LEFT_PAREN;

	if (arg) {
		/* arg is the first node in the tuple */
		struct ivy_ast_node *item = (struct ivy_ast_node *)arg;
		b_queue_push_back(&state->s_items, &item->n_entry);
		state->s_prev = IVY_SYM_COMMA;
	}

	struct expr_parser_state *expr = (struct expr_parser_state *)parser_push_state(ctx, IVY_AST_EXPR, 0);
	expr_add_terminator(expr, IVY_SYM_COMMA);
	expr_add_terminator(expr, IVY_SYM_RIGHT_PAREN);
	expr->s_subexpr_depth = 1;
}

static void collect_children(
	struct ivy_ast_node *node, struct ivy_ast_node_iterator *iterator)
{
	struct ivy_ast_tuple_node *tuple = (struct ivy_ast_tuple_node *)node;

	b_queue_iterator it = {0};
	b_queue_foreach (&it, &tuple->n_members) {
		struct ivy_ast_node *item = b_unbox(struct ivy_ast_node, it.entry, n_entry);
		ast_node_iterator_enqueue_node(iterator, node, item);
	}
}

struct ast_node_type tuple_node_ops = {
	.n_add_child = add_child,
	.n_init_state = init_state,
	.n_collect_children = collect_children,
	.n_state_size = sizeof(struct tuple_parser_state),
	.n_node_size = sizeof(struct ivy_ast_tuple_node),
	.n_symbol_parsers = {
		SYM_PARSER(COMMA, parse_comma),
		SYM_PARSER(RIGHT_PAREN, parse_right_paren),
	},
};