#include "codegen.h"

#include <mie/arg.h>
#include <mie/block.h>
#include <mie/func.h>
#include <mie/module.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

enum lambda_part {
	LAMBDA_NONE,
	LAMBDA_START,
	LAMBDA_ARG,
	LAMBDA_BLOCK,
};

struct lambda_codegen_state {
	struct code_generator_state s_base;
	enum lambda_part s_prev_part;
	struct mie_func *s_lambda;
	struct mie_value *s_self;
	struct mie_block *s_outer_block;
	b_queue s_args;
};

static enum ivy_status switch_to_lambda_func(
	struct ivy_codegen *gen, struct lambda_codegen_state *lambda)
{
	lambda->s_outer_block = mie_builder_get_current_block(gen->c_builder);
	struct mie_block *block = mie_func_get_last_block(lambda->s_lambda);
	if (!block) {
		block = mie_func_create_block(lambda->s_lambda, "entry");
		mie_func_insert_block(lambda->s_lambda, block, NULL);
	}

	if (mie_block_is_terminated(block)) {
		block = mie_func_create_block(lambda->s_lambda, NULL);
		mie_func_insert_block(lambda->s_lambda, block, NULL);
	}

	mie_builder_set_insert_point(gen->c_builder, block);

	return IVY_OK;
}

static enum ivy_status switch_to_outer_block(
	struct ivy_codegen *gen, struct lambda_codegen_state *lambda)
{
	mie_builder_set_insert_point(gen->c_builder, lambda->s_outer_block);
	return IVY_OK;
}

static struct code_generator_result gen_lambda(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct lambda_codegen_state *lambda = (struct lambda_codegen_state *)state;
	if (lambda->s_prev_part != LAMBDA_NONE) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	lambda->s_prev_part = LAMBDA_START;
	lambda->s_lambda = mie_func_create(MIE_FUNC_STATIC, id);
	lambda->s_self = mie_func_add_arg(lambda->s_lambda, id, "ctx");

	switch_to_lambda_func(gen, lambda);

	return CODEGEN_RESULT_OK(0);
}

static struct code_generator_result gen_ident(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct lambda_codegen_state *lambda = (struct lambda_codegen_state *)state;
	if (lambda->s_prev_part != LAMBDA_START
	    && lambda->s_prev_part != LAMBDA_ARG) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	lambda->s_prev_part = LAMBDA_ARG;

	struct ivy_ast_ident_node *ident = (struct ivy_ast_ident_node *)node;
	const char *arg_name = ident->n_content->t_str;
	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	struct mie_value *arg = mie_func_add_arg(lambda->s_lambda, id, arg_name);

	return CODEGEN_RESULT_OK(0);
}

static struct code_generator_result gen_block(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct lambda_codegen_state *lambda = (struct lambda_codegen_state *)state;
	if (lambda->s_prev_part != LAMBDA_START
	    && lambda->s_prev_part != LAMBDA_ARG) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	codegen_push_generator(gen, CODE_GENERATOR_BLOCK, 0, NULL);

	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)
{
	struct lambda_codegen_state *lambda = (struct lambda_codegen_state *)state;
	lambda->s_args = B_QUEUE_INIT;
	lambda->s_prev_part = LAMBDA_NONE;
	return IVY_OK;
}

static enum ivy_status state_fini(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct mie_value **result)
{
	struct lambda_codegen_state *lambda = (struct lambda_codegen_state *)state;

	switch_to_outer_block(gen, lambda);
	mie_module_add_function(gen->c_module, lambda->s_lambda, ".anon");
	*result = MIE_VALUE(lambda->s_lambda);

	return IVY_OK;
}

static struct code_generator_result value_received(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct mie_value *value)
{
	return CODEGEN_RESULT_OK(0);
}

struct code_generator lambda_generator = {
	.g_type = CODE_GENERATOR_LAMBDA,
	.g_state_size = sizeof(struct lambda_codegen_state),
	.g_state_init = state_init,
	.g_state_fini = state_fini,
	.g_value_received = value_received,
	.g_node_generators = {
		NODE_CODEGEN(LAMBDA, gen_lambda),
		NODE_CODEGEN(IDENT, gen_ident),
		NODE_CODEGEN(BLOCK, gen_block),
	},
};