#include "../debug.h"
#include "codegen.h"

#include <blue/core/stringstream.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

enum msg_part {
	MSG_NONE = 0,
	MSG_START,
	MSG_RECIPIENT,
	MSG_SELECTOR,
	MSG_ARG,
};

struct msg_codegen_state {
	struct code_generator_state s_base;
	enum msg_part s_prev_part;

	enum code_generator_flags s_flags;
	struct mie_value *s_recipient;
	struct ivy_ast_selector_node *s_selector;
	struct mie_value **s_args;
	/* the number of args we've collected so far */
	size_t s_nr_args;
	/* the number of args we're expecting based on the selector */
	size_t s_max_args;
};

#if 0
static struct code_generator_result check_expr_root(
		struct ivy_codegen *gen, struct code_generator_state *state,
		struct ivy_ast_node *node)
{
	struct expr_codegen_state *expr = (struct expr_codegen_state *)state;
	if (!expr->s_expr_root) {
		expr->s_expr_root = node;
	}

	return CODEGEN_RESULT_OK(0);
}
#endif

static struct code_generator_result gen_msg(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct msg_codegen_state *msg = (struct msg_codegen_state *)state;
	if (msg->s_prev_part == MSG_NONE) {
		msg->s_prev_part = MSG_START;
		return CODEGEN_RESULT_OK(0);
	}

	codegen_push_generator(gen, CODE_GENERATOR_MSG, 0, NULL);

	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

static struct code_generator_result gen_expr(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct msg_codegen_state *msg = (struct msg_codegen_state *)state;
	if (msg->s_prev_part == MSG_RECIPIENT) {
		/* expected message selector */
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	codegen_push_generator(gen, CODE_GENERATOR_EXPR, 0, NULL);

	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

static struct code_generator_result gen_selector(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct msg_codegen_state *msg = (struct msg_codegen_state *)state;
	if (msg->s_prev_part != MSG_RECIPIENT) {
		/* expected something else */
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	msg->s_selector = (struct ivy_ast_selector_node *)node;
	msg->s_prev_part = MSG_SELECTOR;

	msg->s_nr_args = 0;
	msg->s_max_args = b_queue_length(&msg->s_selector->n_arg_labels);
	msg->s_args = calloc(msg->s_max_args, sizeof(struct mie_value *));

	if (!msg->s_args) {
		return CODEGEN_RESULT_ERR(IVY_ERR_NO_MEMORY);
	}

	return CODEGEN_RESULT_OK(0);
}

static enum ivy_status state_init(
	struct ivy_codegen *gen, struct code_generator_state *state,
	uintptr_t argv, void *argp)
{
	debug_printf("codegen: start of msg\n");
	struct msg_codegen_state *msg = (struct msg_codegen_state *)state;
	msg->s_flags = argv;
	return IVY_OK;
}

static void serialise_selector(
	struct ivy_ast_selector_node *sel, b_stringstream *out)
{
	b_stringstream_add(out, "_M");

	if (sel->n_msg_name) {
		const char *msg_name = sel->n_msg_name->t_str;
		b_stringstream_addf(out, "%zu%s", strlen(msg_name), msg_name);
	} else {
		b_stringstream_add(out, "0");
	}

	b_queue_iterator it;
	b_queue_foreach (&it, &sel->n_arg_labels) {
		struct ivy_token *arg
			= b_unbox(struct ivy_token, it.entry, t_entry);

		if (arg->t_type != IVY_TOK_IDENT && arg->t_type != IVY_TOK_LABEL) {
			b_stringstream_addf(out, "0");
			continue;
		}

		const char *label = arg->t_str;

		if (label) {
			b_stringstream_addf(out, "%zu%s", strlen(label), label);
		} else {
			b_stringstream_addf(out, "0");
		}
	}

	b_stringstream_add(out, "E");
}

static enum ivy_status state_fini(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct code_generator_value *result)
{
	debug_printf("codegen: end of msg\n");

	struct msg_codegen_state *msg = (struct msg_codegen_state *)state;

	b_stringstream str;
	b_stringstream_begin_dynamic(&str);
	serialise_selector(msg->s_selector, &str);
	char *sel = b_stringstream_end(&str);
	struct mie_value *sel_value = mie_ctx_get_selector(gen->c_ctx, sel);
	free(sel);

	enum mie_builder_flags flags = 0;
	struct mie_type *ret_type = NULL;
	const char *value_name = NULL;

#if 0
	if (msg->s_flags & CODEGEN_F_IGNORE_RESULT) {
		ret_type = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_VOID);
		flags = MIE_BUILDER_IGNORE_RESULT;
	} else {
		ret_type = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
		value_name = "msgtmp";
	}
#endif
	ret_type = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	value_name = "msgtmp";

	struct mie_value *msg_send = mie_builder_msg(
		gen->c_builder, ret_type, msg->s_recipient, sel_value,
		msg->s_args, msg->s_nr_args, flags, value_name);

	if (msg->s_args) {
		free(msg->s_args);
	}

	result->v_type = CODE_GENERATOR_VALUE_MIE_VALUE;
	result->v_value.mie_value = msg_send;

	return IVY_OK;
}

static struct code_generator_result value_received(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct code_generator_value *value)
{
	struct msg_codegen_state *msg = (struct msg_codegen_state *)state;
	switch (msg->s_prev_part) {
	case MSG_START:
		msg->s_recipient = value->v_value.mie_value;
		msg->s_prev_part = MSG_RECIPIENT;
		break;
	case MSG_RECIPIENT:
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	case MSG_SELECTOR:
		msg->s_prev_part = MSG_ARG;
	case MSG_ARG:
		if (msg->s_nr_args == msg->s_max_args) {
			/* too many args */
			return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
		}

		msg->s_args[msg->s_nr_args++] = value->v_value.mie_value;
		break;
	default:
		break;
	}

	return CODEGEN_RESULT_OK(0);
}

struct code_generator msg_generator = {
	.g_type = CODE_GENERATOR_MSG,
	.g_state_size = sizeof(struct msg_codegen_state),
	.g_state_init = state_init,
	.g_state_fini = state_fini,
	.g_expr_generator = gen_expr,
	.g_node_generators = {
		NODE_CODEGEN(MSG, gen_msg),
		NODE_CODEGEN(SELECTOR, gen_selector),
	},
	.g_value_received = value_received,
};