#include "block.h"

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

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

void block_add_terminator(struct block_parser_state *state, unsigned short tok)
{
	if (state->s_nr_terminators < BLOCK_TERMINATOR_MAX) {
		state->s_terminators[state->s_nr_terminators++] = tok;
	}
}

void block_copy_terminators(
	const struct block_parser_state *src, struct block_parser_state *dest)
{
	dest->s_nr_terminators = src->s_nr_terminators;

	for (unsigned int i = 0; i < src->s_nr_terminators; i++) {
		dest->s_terminators[i] = src->s_terminators[i];
	}
}

bool block_terminates_at_token(struct block_parser_state *state, unsigned short tok)
{
	for (unsigned int i = 0; i < BLOCK_TERMINATOR_MAX; i++) {
		if (state->s_terminators[i] == tok) {
			return true;
		}
	}

	return false;
}

static struct token_parse_result parse_end(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct block_parser_state *state
		= parser_get_state(ctx, struct block_parser_state);

	struct ivy_ast_block_node *node
		= (struct ivy_ast_block_node *)(state->s_base.s_node);

	int flags = 0;
	if (block_terminates_at_token(state, IVY_KW_END)) {
		flags = PARSE_REPEAT_TOKEN;
	}

	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
	return PARSE_RESULT(IVY_OK, flags);
}

static struct token_parse_result parse_else(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct block_parser_state *state
		= parser_get_state(ctx, struct block_parser_state);

	struct ivy_ast_block_node *node
		= (struct ivy_ast_block_node *)(state->s_base.s_node);

	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
}

static struct token_parse_result parse_keyword(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct block_parser_state *state
		= parser_get_state(ctx, struct block_parser_state);

	struct ivy_ast_block_node *node
		= (struct ivy_ast_block_node *)(state->s_base.s_node);

	if (block_terminates_at_token(state, tok->t_keyword)) {
		parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
		return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
	}

	return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
}

static struct token_parse_result parse_symbol(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct block_parser_state *state
		= parser_get_state(ctx, struct block_parser_state);

	struct ivy_ast_block_node *node
		= (struct ivy_ast_block_node *)(state->s_base.s_node);

	if (block_terminates_at_token(state, tok->t_symbol)) {
		parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
		return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
	}

	return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
}

static struct token_parse_result parse_var(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	parser_push_state(ctx, IVY_AST_VAR, 0);
	return PARSE_RESULT(IVY_OK, 0);
}

static struct token_parse_result parse_expr_begin(
	struct ivy_parser *ctx, struct ivy_token *tok)
{
	struct block_parser_state *state
		= parser_get_state(ctx, struct block_parser_state);

	struct ivy_ast_block_node *node
		= (struct ivy_ast_block_node *)(state->s_base.s_node);

	struct expr_parser_state *expr
		= (struct expr_parser_state *)parser_push_state(
			ctx, IVY_AST_EXPR, 0);

	memcpy(expr->s_terminators, state->s_terminators,
	       sizeof expr->s_terminators);
	expr->s_nr_terminators = state->s_nr_terminators;

	return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);
}

static enum ivy_status add_child(
	struct parser_state *parent, struct ivy_ast_node *child)
{
	struct ivy_ast_block_node *block
		= (struct ivy_ast_block_node *)parent->s_node;

	b_queue_push_back(&block->n_expr, &child->n_entry);

	return IVY_OK;
}

static void collect_children(
	struct ivy_ast_node *node, struct ivy_ast_node_iterator *iterator)
{
	struct ivy_ast_block_node *block = (struct ivy_ast_block_node *)node;
	b_queue_iterator it = {0};
	b_queue_foreach (&it, &block->n_expr) {
		struct ivy_ast_node *expr
			= b_unbox(struct ivy_ast_node, it.entry, n_entry);
		ast_node_iterator_enqueue_node(iterator, node, expr);
	}
}

struct ast_node_type block_node_ops = {
	.n_add_child = add_child,
	.n_collect_children = collect_children,
	.n_state_size = sizeof(struct block_parser_state),
	.n_node_size = sizeof(struct ivy_ast_block_node),
	.n_keyword_parsers = {
		KW_PARSER(VAR, parse_var),
		KW_PARSER(END, parse_end),
		KW_PARSER(ELSE, parse_else),
		KW_PARSER(ELIF, parse_else), /* same behaviour as ELSE */
		KW_PARSER_FALLBACK(parse_keyword),
	},
	.n_symbol_parsers = {
		SYM_PARSER_FALLBACK(parse_symbol),
	},
	.n_expr_parser = {
		.expr_begin = parse_expr_begin,
	},
};