#include "codegen.h"

#include <mie/ir/block.h>
#include <mie/ir/func.h>
#include <mie/ir/module.h>

struct for_codegen_state {
	struct code_generator_state s_base;
	struct ivy_ast_ident_node *s_it_ident;
	struct mie_value *s_container;
	struct mie_value *s_iterator;
	struct mie_value *s_it_value, *s_it_value_inner;
	struct mie_value *s_it_finished;

	struct {
		struct mie_block *b_cond;
		struct mie_block *b_body;
		struct mie_block *b_inc;
		struct mie_block *b_end;
	} s_blocks;
};

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 for_codegen_state *for_loop = (struct for_codegen_state *)state;

	codegen_push_generator(gen, CODE_GENERATOR_EXPR, 0, NULL);
	return CODEGEN_RESULT_OK(CODEGEN_R_REPEAT_NODE);
}

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 for_codegen_state *for_loop = (struct for_codegen_state *)state;
	if (!for_loop->s_it_ident) {
		for_loop->s_it_ident = (struct ivy_ast_ident_node *)node;
		return CODEGEN_RESULT_OK(0);
	}

	return gen_expr(gen, state, node, depth);
}

static struct code_generator_result gen_for_loop(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	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 for_codegen_state *for_loop = (struct for_codegen_state *)state;
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);

	// mie_builder_br(gen->c_builder, for_loop->s_blocks.b_cond);
	//  mie_func_insert_block(func, for_loop->s_blocks.b_cond, NULL);
	//  mie_builder_set_insert_point(gen->c_builder, for_loop->s_blocks.b_cond);

	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 for_codegen_state *for_loop = (struct for_codegen_state *)state;
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);

	for_loop->s_blocks.b_cond = mie_func_create_block(func, "for.cond");
	for_loop->s_blocks.b_body = mie_func_create_block(func, "for.body");
	for_loop->s_blocks.b_inc = mie_func_create_block(func, "for.inc");
	for_loop->s_blocks.b_end = mie_func_create_block(func, "for.end");

	state->s_loop_break_target = for_loop->s_blocks.b_end;
	state->s_loop_repeat_target = for_loop->s_blocks.b_inc;

	return IVY_OK;
}

static enum ivy_status gen_iterator_start(
	struct ivy_codegen *gen, struct for_codegen_state *for_loop)
{
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);

	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	struct mie_value *sel = mie_ctx_get_selector(gen->c_ctx, "_M8iteratorE");
	for_loop->s_iterator = mie_builder_msg(
		gen->c_builder, id, for_loop->s_container, sel, NULL, 0, 0,
		"for.it");
	mie_builder_br(gen->c_builder, for_loop->s_blocks.b_cond);
	return IVY_OK;
}

static enum ivy_status gen_cond_block(
	struct ivy_codegen *gen, struct for_codegen_state *for_loop)
{
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);
	mie_func_insert_block(func, for_loop->s_blocks.b_cond, NULL);
	mie_builder_set_insert_point(gen->c_builder, for_loop->s_blocks.b_cond);

	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	struct mie_value *sel = mie_ctx_get_selector(gen->c_ctx, "_M5valueE");
	struct mie_value *null_value = mie_ctx_get_null(gen->c_ctx);
	for_loop->s_it_value = mie_builder_msg(
		gen->c_builder, id, for_loop->s_iterator, sel, NULL, 0, 0,
		"for.value");
	for_loop->s_it_finished = mie_builder_cmp_eq(
		gen->c_builder, for_loop->s_it_value, null_value,
		"for.finished");

	mie_builder_br_if(
		gen->c_builder, for_loop->s_it_finished,
		for_loop->s_blocks.b_end, for_loop->s_blocks.b_body);

	return IVY_OK;
}

static enum ivy_status gen_body(
	struct ivy_codegen *gen, struct for_codegen_state *for_loop)
{
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);
	mie_func_insert_block(func, for_loop->s_blocks.b_body, NULL);
	mie_builder_set_insert_point(gen->c_builder, for_loop->s_blocks.b_body);

	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	for_loop->s_it_value_inner = mie_builder_alloca(
		gen->c_builder, id, for_loop->s_it_ident->n_content->t_str);
	mie_builder_store(
		gen->c_builder, for_loop->s_it_value, for_loop->s_it_value_inner);

	return IVY_OK;
}

static enum ivy_status gen_inc_block(
	struct ivy_codegen *gen, struct for_codegen_state *for_loop)
{
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);
	mie_builder_br(gen->c_builder, for_loop->s_blocks.b_inc);

	mie_func_insert_block(func, for_loop->s_blocks.b_inc, NULL);
	mie_builder_set_insert_point(gen->c_builder, for_loop->s_blocks.b_inc);

	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	struct mie_value *sel = mie_ctx_get_selector(gen->c_ctx, "_M8moveNextE");
	mie_builder_msg(
		gen->c_builder, id, for_loop->s_iterator, sel, NULL, 0, 0, NULL);
	mie_builder_br(gen->c_builder, for_loop->s_blocks.b_cond);

	return IVY_OK;
}

static enum ivy_status gen_end_block(
	struct ivy_codegen *gen, struct for_codegen_state *for_loop)
{
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);
	mie_func_insert_block(func, for_loop->s_blocks.b_end, NULL);
	mie_builder_set_insert_point(gen->c_builder, for_loop->s_blocks.b_end);

	return IVY_OK;
}

static enum ivy_status state_fini(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct code_generator_value *result)
{
	struct for_codegen_state *for_loop = (struct for_codegen_state *)state;
	gen_inc_block(gen, for_loop);
	gen_end_block(gen, for_loop);
	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 for_codegen_state *for_loop = (struct for_codegen_state *)state;
	struct mie_func *func = mie_builder_get_current_func(gen->c_builder);

	if (!for_loop->s_container) {
		for_loop->s_container = code_generator_value_get_mie_value(value);
		gen_iterator_start(gen, for_loop);
		gen_cond_block(gen, for_loop);
		gen_body(gen, for_loop);
		return CODEGEN_RESULT_OK(0);
	}

	return CODEGEN_RESULT_OK(0);
}

static enum ivy_status resolve_var(
	struct ivy_codegen *gen, struct code_generator_state *state,
	const char *ident, struct codegen_var *var)
{
	struct for_codegen_state *for_loop = (struct for_codegen_state *)state;

	if (strcmp(ident, for_loop->s_it_ident->n_content->t_str) != 0) {
		return IVY_ERR_NO_ENTRY;
	}

	var->v_node = (struct ivy_ast_node *)for_loop->s_it_ident;
	var->v_type = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	var->v_value = for_loop->s_it_value_inner;
	var->v_flags = CODEGEN_VAR_F_PTR;

	return IVY_OK;
}

struct code_generator for_loop_generator = {
	.g_type = CODE_GENERATOR_FOR_LOOP,
	.g_state_size = sizeof(struct for_codegen_state),
	.g_state_init = state_init,
	.g_state_fini = state_fini,
	.g_resolve_var = resolve_var,
	.g_value_received = value_received,
	.g_expr_generator = gen_expr,
	.g_node_generators = {
		NODE_CODEGEN(FOR_LOOP, gen_for_loop),
		NODE_CODEGEN(IDENT, gen_ident),
		NODE_CODEGEN(BLOCK, gen_block),
	},
};