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

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

struct selector_parser_state {
	struct parser_state s_base;
	unsigned int s_prev;
	bool s_complete;
};

#define CHECK_SELECTOR_COMPLETE()                                              \
	do {                                                                   \
		if (state->s_complete) {                                       \
			parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);       \
			return PARSE_RESULT(IVY_OK, PARSE_REPEAT_TOKEN);       \
		}                                                              \
	} while (0)

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	if (sel->n_recipient != IVY_SELECTOR_RECIPIENT_NONE) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	sel->n_recipient = IVY_SELECTOR_RECIPIENT_CLASS;
	return PARSE_RESULT(IVY_OK, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	if (sel->n_recipient != IVY_SELECTOR_RECIPIENT_NONE) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	sel->n_recipient = IVY_SELECTOR_RECIPIENT_OBJECT;
	return PARSE_RESULT(IVY_OK, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	CHECK_SELECTOR_COMPLETE();

	if (state->s_prev == 0) {
		/* message name */
		sel->n_msg_name = tok;
		state->s_prev = IVY_TOK_IDENT;
		state->s_complete = true;
		return PARSE_RESULT(IVY_OK, 0);
	}

	if (state->s_prev == IVY_TOK_LABEL) {
		/* internal parameter name */
		b_queue_push_back(&sel->n_arg_names, &tok->t_entry);
		state->s_prev = IVY_TOK_IDENT;
		state->s_complete = true;
		return PARSE_RESULT(IVY_OK, 0);
	}

	return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	if (sel->n_recipient == IVY_SELECTOR_RECIPIENT_NONE
	    && state->s_prev != IVY_TOK_IDENT
	    && state->s_prev != IVY_SYM_LEFT_PAREN) {
		/* if recipient is not NONE, this selector appears at the beginning of a message
		 * handler. only then is a label without a preceding identifier allowed. */
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	b_queue_push_back(&sel->n_arg_labels, &tok->t_entry);
	state->s_prev = IVY_TOK_LABEL;
	state->s_complete = false;

	return PARSE_RESULT(IVY_OK, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	CHECK_SELECTOR_COMPLETE();

	if (!b_queue_empty(&sel->n_arg_labels)
	    && state->s_prev != IVY_SYM_RIGHT_PAREN) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

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

	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
	state->s_prev = IVY_TOK_LINEFEED;
	return PARSE_RESULT(IVY_OK, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	if (state->s_prev != IVY_TOK_IDENT || !b_queue_empty(&sel->n_arg_labels)) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	state->s_prev = IVY_SYM_LEFT_PAREN;
	return PARSE_RESULT(IVY_OK, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	if (state->s_prev != IVY_TOK_IDENT || b_queue_empty(&sel->n_arg_labels)) {
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

	state->s_prev = IVY_SYM_RIGHT_PAREN;
	state->s_complete = true;
	parser_pop_state(ctx, STATE_ADD_NODE_TO_PARENT);
	return PARSE_RESULT(IVY_OK, 0);
}

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	switch (state->s_prev) {
	case IVY_SYM_RIGHT_PAREN:
		/* this looks like a complex message selector */
		if (b_queue_empty(&sel->n_arg_labels)
		    || b_queue_empty(&sel->n_arg_names)) {
			/* no message args */
			return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
		}

		if (!sel->n_msg_name) {
			/* no message name */
			return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
		}
		break;
	case IVY_TOK_IDENT:
		/* this looks like a unary or keyword message. */
		if (!b_queue_empty(&sel->n_arg_labels)
		    && b_queue_empty(&sel->n_arg_names)) {
			/* keyword message with no arg names. */
			return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
		}
		break;
	default:
		/* not sure what we're parsing. unknown token at end of selector. */
		return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
	}

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

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

	struct ivy_ast_selector_node *sel
		= (struct ivy_ast_selector_node *)state->s_base.s_node;

	CHECK_SELECTOR_COMPLETE();

	return PARSE_RESULT(IVY_ERR_BAD_SYNTAX, 0);
}

static void to_string(struct ivy_ast_node *node, b_string *str)
{
	struct ivy_ast_selector_node *sel = (struct ivy_ast_selector_node *)node;

	b_string_append_cstrf(
		str, "%s [", ivy_ast_node_type_to_string(node->n_type));

	switch (sel->n_recipient) {
	case IVY_SELECTOR_RECIPIENT_CLASS:
		b_string_append_cstr(str, "+");
		break;
	case IVY_SELECTOR_RECIPIENT_OBJECT:
		b_string_append_cstr(str, "-");
		break;
	default:
		/* this will occur if the selector is being used to send a
		   message at runtime, rather than as part of a message
		   handler definition. */
		break;
	}

	if (sel->n_msg_name) {
		b_string_append_cstr(str, sel->n_msg_name->t_str);
	}

	if (sel->n_msg_name && !b_queue_empty(&sel->n_arg_labels)) {
		b_string_append_cstr(str, "(");
	}

	b_queue_entry *label_entry = b_queue_first(&sel->n_arg_labels);
	b_queue_entry *name_entry = b_queue_first(&sel->n_arg_names);

	int i = 0;
	while (label_entry) {
		if (i > 0) {
			b_string_append_cstr(str, " ");
		}

		struct ivy_token *label, *name;

		label = b_unbox(struct ivy_token, label_entry, t_entry);
		name = b_unbox(struct ivy_token, name_entry, t_entry);

		if (label && label->t_type == IVY_TOK_LABEL && label->t_str) {
			b_string_append_cstrf(str, "%s:", label->t_str);
		} else {
			b_string_append_cstrf(str, "_:");
		}

		if (name) {
			b_string_append_cstrf(str, "%s", name->t_str);
		}

		if (name) {
			i++;
		}

		label_entry = b_queue_next(label_entry);
		name_entry = b_queue_next(name_entry);
	}

	if (sel->n_msg_name && !b_queue_empty(&sel->n_arg_labels)) {
		b_string_append_cstr(str, ")");
	}

	b_string_append_cstr(str, "]");
}

static void init_state(struct ivy_parser *ctx, struct parser_state *sp, uintptr_t arg)
{
	struct selector_parser_state *state = (struct selector_parser_state *)sp;
	state->s_prev = 0;
	state->s_complete = false;
}

struct ast_node_type selector_node_ops = {
        .n_init_state = init_state,
	.n_to_string = to_string,
        .n_state_size = sizeof(struct selector_parser_state),
        .n_node_size = sizeof(struct ivy_ast_selector_node),
        .n_token_parsers = {
		TOK_PARSER(IDENT, parse_ident),
		TOK_PARSER(LABEL, parse_label),
		TOK_PARSER_FALLBACK(parse_other),
	},
	.n_symbol_parsers = {
		SYM_PARSER(PLUS, parse_plus),
		SYM_PARSER(HYPHEN, parse_hyphen),
		SYM_PARSER(LEFT_PAREN, parse_left_paren),
		SYM_PARSER(RIGHT_PAREN, parse_right_paren),
		SYM_PARSER(PIPE, parse_pipe),
	},
};