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

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

struct var_codegen_state {
	struct code_generator_state s_base;
	unsigned int s_prev_node;
	/* TODO support multiple idents (for tuples) */
	struct ivy_ast_ident_node *s_var_ident;
	struct mie_value *s_var_ptr;
	struct mie_value *s_value;
};

static struct code_generator_result gen_var(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct var_codegen_state *var = (struct var_codegen_state *)state;
	if (var->s_prev_node != 0) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	var->s_prev_node = IVY_AST_VAR;
	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 var_codegen_state *var = (struct var_codegen_state *)state;
	if (var->s_prev_node != IVY_AST_VAR) {
		/* TODO support tuple assignment */
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	struct ivy_ast_ident_node *ident = (struct ivy_ast_ident_node *)node;
	const char *var_name = ident->n_content->t_str;

	/* TODO get type from expression */
	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
	struct mie_value *var_ptr
		= mie_builder_alloca(gen->c_builder, id, var_name);

	var->s_var_ident = (struct ivy_ast_ident_node *)node;
	var->s_var_ptr = var_ptr;
	var->s_prev_node = IVY_AST_IDENT;

	return CODEGEN_RESULT_OK(0);
}

static struct code_generator_result gen_value_expr(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct ivy_ast_node *node, size_t depth)
{
	struct var_codegen_state *var = (struct var_codegen_state *)state;
	if (var->s_prev_node != IVY_AST_IDENT && var->s_prev_node != IVY_AST_TUPLE) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	codegen_push_generator(gen, CODE_GENERATOR_EXPR, 0);

	return CODEGEN_RESULT_OK(CODEGEN_REPEAT_NODE);
}

#if 0
static struct code_generator_result gen_var_ref(
		struct ivy_codegen *gen, struct code_generator_state *state,
		struct ivy_ast_node *node)
{
	struct ivy_ast_ident_node *ident = (struct ivy_ast_ident_node *)node;
	struct codegen_var *var
		= codegen_resolve_variable(gen, ident->n_content->t_str);

	if (var) {
		/* this variable has been defined previously, and we have a
		 * mie_value representing its location on the stack */
		struct codegen_value *var_value
			= codegen_value_create(node, var->v_ptr);
		codegen_push_value(gen, var_value);
		return CODEGEN_RESULT_OK(0);
	}

	/* this variable either doesn't exist, or is a global variable */
	struct codegen_value *var_value = codegen_value_create(node, NULL);
	codegen_push_value(gen, var_value);

	return CODEGEN_RESULT_OK(0);
}
#endif

static enum ivy_status state_init(
	struct ivy_codegen *gen, struct code_generator_state *state)
{
	printf("codegen: start of var decl\n");
	return IVY_OK;
}

static enum ivy_status state_fini(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct mie_value **result)
{
	printf("codegen: end of var decl\n");
	struct var_codegen_state *var = (struct var_codegen_state *)state;

	struct code_generator_scope *scope = codegen_get_current_scope(gen);
	code_generator_scope_put_variable(scope, var->s_var_ident, var->s_var_ptr);

	if (var->s_value) {
		mie_builder_store(gen->c_builder, var->s_value, var->s_var_ptr);
	}
	return IVY_OK;
}

static struct code_generator_result value_received(
	struct ivy_codegen *gen, struct code_generator_state *state,
	struct mie_value *value)
{
	printf("codegen: var decl value received\n");

	struct var_codegen_state *var = (struct var_codegen_state *)state;
	if (!var->s_var_ptr) {
		return CODEGEN_RESULT_ERR(IVY_ERR_BAD_SYNTAX);
	}

	var->s_value = value;

	return CODEGEN_RESULT_OK(CODEGEN_POP_GENERATOR);
}

struct code_generator var_generator = {
	.g_type = CODE_GENERATOR_VAR,
	.g_state_size = sizeof(struct var_codegen_state),
	.g_state_init = state_init,
	.g_state_fini = state_fini,
	.g_value_received = value_received,
	.g_node_generators = {
		[IVY_AST_VAR] = gen_var,
		[IVY_AST_IDENT] = gen_ident,
		[IVY_AST_INT] = gen_value_expr,
		[IVY_AST_OP] = gen_value_expr,
	},
};