#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <stdarg.h>
#include <string.h>
#include <assert.h>

#include "nlr.h"
#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "lexer.h"
#include "lexerunix.h"
#include "parse.h"
#include "obj.h"
#include "compile.h"
#include "runtime0.h"
#include "runtime.h"
#include "map.h"
#include "builtin.h"

mp_obj_t sys_path;

mp_obj_t mp_builtin___import__(int n_args, mp_obj_t *args) {
    /*
    printf("import:\n");
    for (int i = 0; i < n; i++) {
        printf("  ");
        mp_obj_print(args[i]);
        printf("\n");
    }
    */

    qstr mod_name = mp_obj_str_get_qstr(args[0]);

    mp_obj_t loaded = mp_obj_module_get(mod_name);
    if (loaded != MP_OBJ_NULL) {
        return loaded;
    }

    // find the file to import
    uint mod_name_len;
    const byte* mod_name_p = qstr_data(mod_name, &mod_name_len);
    mp_lexer_t *lex = NULL;

    uint path_num = 0;
    mp_obj_t *path_items;
    if (sys_path != MP_OBJ_NULL) {
        mp_obj_list_get(sys_path, &path_num, &path_items);
    }

    if (path_num == 0) {
        CHECKBUF(fname, PATH_MAX);
        CHECKBUF_APPEND(fname, mod_name_p, mod_name_len);
        CHECKBUF_APPEND(fname, ".py", sizeof(".py") - 1);
        CHECKBUF_APPEND_0(fname);
        lex = mp_lexer_new_from_file(fname);
    } else {
        for (int i = 0; i < path_num; i++) {
            CHECKBUF(fname, PATH_MAX);
            uint p_len;
            const byte *p = mp_obj_str_get_data(path_items[i], &p_len);
            if (p_len > 0) {
                CHECKBUF_APPEND(fname, p, p_len);
                CHECKBUF_APPEND(fname, "/", 1);
            }
            CHECKBUF_APPEND(fname, mod_name_p, mod_name_len);
            CHECKBUF_APPEND(fname, ".py", sizeof(".py") - 1);
            CHECKBUF_APPEND_0(fname);
            lex = mp_lexer_new_from_file(fname);
            if (lex != NULL) {
                break;
            }
        }
    }

    if (lex == NULL) {
        nlr_jump(mp_obj_new_exception_msg_varg(MP_QSTR_ImportError, "ImportError: No module named '%s'", mod_name_p));
    }
    qstr source_name = mp_lexer_source_name(lex);

    // create a new module object
    mp_obj_t module_obj = mp_obj_new_module(mod_name);

    // save the old context
    mp_map_t *old_locals = rt_locals_get();
    mp_map_t *old_globals = rt_globals_get();

    // set the new context
    rt_locals_set(mp_obj_module_get_globals(module_obj));
    rt_globals_set(mp_obj_module_get_globals(module_obj));

    // parse the imported script
    qstr parse_exc_id;
    const char *parse_exc_msg;
    mp_parse_node_t pn = mp_parse(lex, MP_PARSE_FILE_INPUT, &parse_exc_id, &parse_exc_msg);
    mp_lexer_free(lex);

    if (pn == MP_PARSE_NODE_NULL) {
        // parse error; clean up and raise exception
        rt_locals_set(old_locals);
        rt_globals_set(old_globals);
        nlr_jump(mp_obj_new_exception_msg(parse_exc_id, parse_exc_msg));
    }

    // compile the imported script
    mp_obj_t module_fun = mp_compile(pn, source_name, false);
    mp_parse_node_free(pn);

    if (module_fun == mp_const_none) {
        // TODO handle compile error correctly
        rt_locals_set(old_locals);
        rt_globals_set(old_globals);
        return mp_const_none;
    }

    // complied successfully, execute it
    nlr_buf_t nlr;
    if (nlr_push(&nlr) == 0) {
        rt_call_function_0(module_fun);
        nlr_pop();
    } else {
        // exception; restore context and re-raise same exception
        rt_locals_set(old_locals);
        rt_globals_set(old_globals);
        nlr_jump(nlr.ret_val);
    }
    rt_locals_set(old_locals);
    rt_globals_set(old_globals);

    return module_obj;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_builtin___import___obj, 1, 5, mp_builtin___import__);