#include <dcfg.h>

#include <alloca.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>

void walk_value(dcfg_Value *value, bool evaluate, int indent, bool first);
#define WALK(v, e, i) walk_value((v), (e), (i), true)

static void print_indent(int indent)
{
	for (int i = 0; i < indent; ++i)
		putchar('\t');
}

int main(int argc, char *argv[])
{
	if (argc < 2) {
		printf("Usage: %s <dcfg file>\n", argv[0]);
		return 1;
	}

	dcfg_InstanceCreateInfo ci = { 0 };
	dcfg_Instance *instance = dcfg_make_instance(&ci);
	if (!instance) {
		printf("Failed to create DCFG instance. Error: %s\n",
		    dcfg_last_error(instance));
		return 1;
	}

	dcfg_Value *value = dcfg_parse(instance, dcfg_SV(argv[1]));
	if (!value) {
		printf("Failed to parse DCFG file. Error: %s\n",
		    dcfg_last_error(instance));
		dcfg_destroy_instance(instance);
		return 1;
	}

	WALK(value, false, 0);

	dcfg_destroy(value);
	dcfg_destroy_instance(instance);
}

void walk_value(dcfg_Value *value, bool evaluate, int indent, bool first)
{
	if (first)
		print_indent(indent);

	dcfg_ValueType type = dcfg_Value_type_ex(value, evaluate);

	switch (type) {
	case dcfg_ValueType_Nil:
		printf("null");
		break;

	case dcfg_ValueType_Boolean: {
		bool b;
		dcfg_Value_get_boolean(value, &b);
		printf("%s", b ? "true" : "false");
	} break;

	case dcfg_ValueType_Integer: {
		int64_t v;
		dcfg_Value_get_integer(value, &v);
		printf("%" PRId64, v);
	} break;

	case dcfg_ValueType_Real: {
		double v;
		dcfg_Value_get_real(value, &v);
		printf("%g", v);
	} break;

	case dcfg_ValueType_String: {
		dcfg_StringView sv;
		dcfg_Value_get_string(value, &sv);
		printf("\"%.*s\"", (int)sv.size, sv.data);
	} break;

	case dcfg_ValueType_Path: {
		dcfg_StringView sv;
		dcfg_Value_get_path(value, &sv);
		printf("<path \"%.*s\">", (int)sv.size, sv.data);
	} break;

	case dcfg_ValueType_Object: {
		size_t n = 0;
		dcfg_Value_get_object_keys(value, 0, &n, NULL);
		dcfg_StringView *keys
		    = n ? (dcfg_StringView *)alloca(n * sizeof(*keys)) : NULL;
		dcfg_Value_get_object_keys(value, n, &n, keys);

		printf("{\n");
		for (size_t i = 0; i < n; ++i) {
			dcfg_Value *child;
			if (!dcfg_Value_get_object_field_ex(
			        value, keys[i], &child, evaluate))
				continue;

			print_indent(indent + 1);
			printf("\"%.*s\": ", (int)keys[i].size, keys[i].data);
			walk_value(child, evaluate, indent + 1, false);
			if (i + 1 < n)
				printf(",");
			printf("\n");
		}
		print_indent(indent);
		printf("}");
	} break;

	case dcfg_ValueType_Array: {
		size_t sz = 0;
		dcfg_Value_get_array_size(value, &sz);

		printf("[\n");
		for (size_t i = 0; i < sz; ++i) {
			dcfg_Value *item;
			if (!dcfg_Value_get_array_item_ex(value, i, &item, evaluate))
				continue;

			print_indent(indent + 1);
			walk_value(item, evaluate, indent + 1, false);
			if (i + 1 < sz)
				printf(",");
			printf("\n");
		}
		print_indent(indent);
		printf("]");
	} break;

	case dcfg_ValueType_Function: {
		dcfg_Value *body = NULL;

		if (dcfg_Value_get_function_body_ex(value, &body, evaluate) && body) {
			printf("<fn>\t");
			walk_value(body, evaluate, indent + 1, false);
		} else {
			printf("<builtin-fn>");
		}
	} break;

	case dcfg_ValueType_FunctionCall:
		if (evaluate) {
			dcfg_Value *res;
			if (dcfg_Value_evaluate(value, &res))
				walk_value(res, evaluate, indent, first);
			else
				printf("<error-evaluating-call>");
		} else {
			printf("<function-call>");
		}
		break;

	default:
		printf("<unknown>");
		break;
	}

	if (indent == 0) {
		putchar('\n');
	}
}