#include <lean/lean.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

extern uint8_t mlang_http_get_body(const char *url, char **out_body, char **out_error);
extern uint8_t mlang_nickel_eval(const char *source, char **out_body, char **out_error);
extern uint8_t mlang_nickel_eval_file(const char *path, char **out_body, char **out_error);
extern uint8_t mlang_json_eval(const char *source, char **out_body, char **out_error);
extern uint8_t mlang_aturi_parse(const char *source, char **out_body, char **out_error);
extern void mlang_http_string_free(char *ptr);
extern lean_obj_res lean_mk_io_user_error(lean_obj_arg msg);

LEAN_EXPORT lean_obj_res mlang_http_get(b_lean_obj_arg url, lean_obj_arg world) {
    (void)world;
    char *body = NULL;
    char *error = NULL;
    const char *url_cstr = lean_string_cstr(url);
    uint8_t ok = mlang_http_get_body(url_cstr, &body, &error);
    if (ok) {
        lean_object *result = lean_mk_string(body);
        mlang_http_string_free(body);
        return lean_io_result_mk_ok(result);
    } else {
        if (error == NULL) {
            error = strdup("unknown HTTP error");
        }
        lean_object *msg = lean_mk_string(error);
        lean_object *io_error = lean_mk_io_user_error(msg);
        mlang_http_string_free(error);
        return lean_io_result_mk_error(io_error);
    }
}

static lean_obj_res wrap_string_result(
    uint8_t ok,
    char *body,
    char *error
) {
    if (ok) {
        lean_object *result = lean_mk_string(body);
        mlang_http_string_free(body);
        return lean_io_result_mk_ok(result);
    } else {
        if (error == NULL) {
            error = strdup("unknown host error");
        }
        lean_object *msg = lean_mk_string(error);
        lean_object *io_error = lean_mk_io_user_error(msg);
        mlang_http_string_free(error);
        return lean_io_result_mk_error(io_error);
    }
}

LEAN_EXPORT lean_obj_res mlang_nickel_eval_string(b_lean_obj_arg source, lean_obj_arg world) {
    (void)world;
    char *body = NULL;
    char *error = NULL;
    uint8_t ok = mlang_nickel_eval(lean_string_cstr(source), &body, &error);
    return wrap_string_result(ok, body, error);
}

LEAN_EXPORT lean_obj_res mlang_nickel_eval_file_string(b_lean_obj_arg path, lean_obj_arg world) {
    (void)world;
    char *body = NULL;
    char *error = NULL;
    uint8_t ok = mlang_nickel_eval_file(lean_string_cstr(path), &body, &error);
    return wrap_string_result(ok, body, error);
}

LEAN_EXPORT lean_obj_res mlang_json_eval_string(b_lean_obj_arg source, lean_obj_arg world) {
    (void)world;
    char *body = NULL;
    char *error = NULL;
    uint8_t ok = mlang_json_eval(lean_string_cstr(source), &body, &error);
    return wrap_string_result(ok, body, error);
}

LEAN_EXPORT lean_obj_res mlang_aturi_parse_string(b_lean_obj_arg source, lean_obj_arg world) {
    (void)world;
    char *body = NULL;
    char *error = NULL;
    uint8_t ok = mlang_aturi_parse(lean_string_cstr(source), &body, &error);
    return wrap_string_result(ok, body, error);
}