from genericpath import exists
import json
import os
import uuid
import sys
import re


def load_json(p):
    with open(p, 'r') as f:
        return json.loads(f.read())


def dump_json(p, j, exist_ok=False, override=False):
    if os.path.exists(p):
        if exist_ok:
            if not override:
                return
        else:
            print(f"{p} already exist")
            sys.exit(0)

    with open(p, 'w') as f:
        f.write(json.dumps(j, indent=2, ensure_ascii=False))


def parse_no_name(d):
    p = r'(\d+)\.(.*)'
    m = re.search(p, d)

    try:
        no = int(m.group(1))
        dir_name = m.group(2)
    except:
        sys.exit(0)

    return no, dir_name


def gen_tree(data_path):
    root = {}

    def gen_node_id():
        return ''.join(str(uuid.uuid5(uuid.NAMESPACE_URL, 'skill_tree')).split('-'))

    def list_dir(p):
        v = os.listdir(p)
        v.sort()
        for no_name in v:
            no_dir = os.path.join(p, no_name)
            if os.path.isdir(no_dir):
                yield no_dir, no_name

    def ensure_node_id(cfg_path, cfg):
        if cfg.get('node_id') is None:
            cfg['node_id'] = gen_node_id()
            dump_json(cfg_path, cfg, exist_ok=True, override=True)

    def make_node(name, node_id, keywords, children=None):
        node = {}
        node_children = children or []
        node[name] = {
            'node_id': node_id,
            'keywords': keywords,
            'children': node_children
        }
        return node, node_children

    # 根节点
    cfg_path = os.path.join(data_path, 'config.json')
    cfg = load_json(cfg_path)
    ensure_node_id(cfg_path, cfg)
    tree_node = {
        "node_id": cfg['node_id'],
        "keywords": cfg['keywords'],
        "children": []
    }
    root[cfg['tree_name']] = tree_node

    # 难度节点
    for level_no_dir, level_no_name in list_dir(data_path):
        print(level_no_dir)
        no, level_name = parse_no_name(level_no_name)
        cfg_path = os.path.join(level_no_dir, 'config.json')
        cfg = load_json(cfg_path)
        ensure_node_id(cfg_path, cfg)

        level_node, level_node_children = make_node(
            level_name, cfg['node_id'], cfg['keywords'])
        tree_node['children'].append(level_node)

        # 章节点
        for chapter_no_dir, chapter_no_name in list_dir(level_no_dir):
            no, chapter_name = parse_no_name(chapter_no_name)
            cfg_path = os.path.join(chapter_no_dir, 'config.json')
            ensure_node_id(cfg_path, cfg)
            cfg = load_json(cfg_path)

            chapter_node, chapter_node_children = make_node(
                chapter_name, cfg['node_id'], cfg['keywords'])
            level_node_children.append(chapter_node)

            # 知识点
            for section_no_dir, section_no_name in list_dir(chapter_no_dir):
                no, section_name = parse_no_name(section_no_name)
                cfg_path = os.path.join(section_no_dir, 'config.json')
                ensure_node_id(cfg_path, cfg)
                cfg = load_json(cfg_path)

                section_node, section_node_children = make_node(
                    section_name, cfg['node_id'], cfg['keywords'], cfg['children'])
                chapter_node_children.append(section_node)

                # 确保习题分配了习题ID
                for export in cfg['export']:
                    if export.get('exercise_id') is None:
                        export['exercise_id'] = gen_node_id()
                dump_json(cfg_path, cfg, exist_ok=True, override=True)

    # 保存技能树骨架
    tree_path = os.path.join(data_path, 'tree.json')
    dump_json(tree_path, root, exist_ok=True, override=True)