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

id_set = set()

logger = logging.getLogger(__name__)


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:
            logger.error(f"{p} already exist")
            sys.exit(0)

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


def ensure_config(path):
    config_path = os.path.join(path, "config.json")
    if not os.path.exists(config_path):
        node = {"keywords": []}
        dump_json(config_path, node, exist_ok=True, override=False)
        return node
    else:
        return load_json(config_path)


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 check_export(base, cfg):
    flag = False
    exports = []
    for export in cfg.get('export', []):
        ecfg_path = os.path.join(base, export)
        if os.path.exists(ecfg_path):
            exports.append(export)
        else:
            flag = True
    if flag:
        cfg["export"] = exports
    return flag


def gen_node_id():
    return "oceanbase-" + uuid.uuid4().hex


class TreeWalker:
    def __init__(self, root, tree_name, title=None):
        self.name = tree_name
        self.root = root
        self.title = tree_name if title is None else title
        self.tree = {}

    def walk(self):
        root = self.load_root()
        root_node = {
            "node_id": root["node_id"],
            "keywords": root["keywords"],
            "children": []
        }
        self.tree[root["tree_name"]] = root_node
        self.load_levels(root_node)
        self.load_chapters(self.root, root_node)
        for index, level in enumerate(root_node["children"]):
            level_title = list(level.keys())[0]
            level_node = list(level.values())[0]
            level_path = os.path.join(self.root, f"{index+1}.{level_title}")
            self.load_chapters(level_path, level_node)
            for index, chapter in enumerate(level_node["children"]):
                chapter_title = list(chapter.keys())[0]
                chapter_node = list(chapter.values())[0]
                chapter_path = os.path.join(level_path, f"{index+1}.{chapter_title}")
                self.load_sections(chapter_path, chapter_node)
                for index, section_node in enumerate(chapter_node["children"]):
                    section_title = list(section_node.keys())[0]
                    full_path = os.path.join(chapter_path, f"{index}.{section_title}")
                    if os.path.isdir(full_path):
                        self.ensure_exercises(full_path)

        tree_path = os.path.join(self.root, "tree.json")
        dump_json(tree_path, self.tree, exist_ok=True, override=True)
        return self.tree

    def load_levels(self, root_node):
        levels = []
        for level in os.listdir(self.root):
            if not os.path.isdir(level):
                continue
            level_path = os.path.join(self.root, level)
            num, config = self.load_level_node(level_path)
            levels.append((num, config))
        levels.sort(key=lambda item: item[0])
        root_node["children"] = [item[1] for item in levels]
        return root_node

    def load_level_node(self, level_path):
        config = self.ensure_level_config(level_path)
        num, name = self.extract_node_env(level_path)

        result = {
            name: {
                "node_id": config["node_id"],
                "keywords": config["keywords"],
                "children": [],
            }
        }

        return num, result

    def load_chapters(self, base, level_node):
        chapters = []
        for name in os.listdir(base):
            full_name = os.path.join(base, name)
            if os.path.isdir(full_name):
                num, chapter = self.load_chapter_node(full_name)
                chapters.append((num, chapter))

        chapters.sort(key=lambda item: item[0])
        level_node["children"] = [item[1] for item in chapters]
        return level_node

    def load_sections(self, base, chapter_node):
        sections = []
        for name in os.listdir(base):
            full_name = os.path.join(base, name)
            if os.path.isdir(full_name):
                num, section = self.load_section_node(full_name)
                sections.append((num, section))

        sections.sort(key=lambda item: item[0])
        chapter_node["children"] = [item[1] for item in sections]
        return chapter_node

    def ensure_chapters(self):
        for subdir in os.listdir(self.root):
            self.ensure_level_config(subdir)

    def load_root(self):
        config_path = os.path.join(self.root, "config.json")
        if not os.path.exists(config_path):
            config = {
                "tree_name": self.name,
                "keywords": [],
                "node_id": self.gen_node_id(),
            }
            dump_json(config_path, config, exist_ok=True, override=True)
        else:
            config = load_json(config_path)
            flag, result = self.ensure_node_id(config)
            if flag:
                dump_json(config_path, result, exist_ok=True, override=True)

        return config

    def ensure_level_config(self, path):
        config_path = os.path.join(path, "config.json")
        if not os.path.exists(config_path):
            config = {
                "node_id": self.gen_node_id()
            }
            dump_json(path, config, exist_ok=True, override=True)
        else:
            config = load_json(config_path)
            flag, result = self.ensure_node_id(config)
            if flag:
                dump_json(path, config, exist_ok=True, override=True)
        return config

    def ensure_chapter_config(self, path):
        config_path = os.path.join(path, "config.json")
        if not os.path.exists(config_path):
            config = {
                "node_id": self.gen_node_id(),
                "keywords": []
            }
            dump_json(path, config, exist_ok=True, override=True)
        else:
            config = load_json(config_path)
            flag, result = self.ensure_node_id(config)
            if flag:
                dump_json(path, config, exist_ok=True, override=True)
        return config

    def ensure_section_config(self, path):
        config_path = os.path.join(path, "config.json")
        if not os.path.exists(config_path):
            config = {
                "node_id": self.gen_node_id(),
                "keywords": [],
                "children":[],
                "export":[]
            }
            dump_json(config_path, config, exist_ok=True, override=True)
        else:
            config = load_json(config_path)
            flag, result = self.ensure_node_id(config)
            if flag:
                dump_json(config_path, config, exist_ok=True, override=True)
        return config

    def ensure_node_id(self, config):
        if "node_id" not in config:
            config["node_id"] = self.gen_node_id()
            return True, config
        else:
            return False, config

    def gen_node_id(self):
        return f"{self.name}-{uuid.uuid4().hex}"

    def extract_node_env(self, path):
        _, dir = os.path.split(path)
        number, title = dir.split(".", 1)
        return int(number), title

    def load_chapter_node(self, full_name):
        config = self.ensure_chapter_config(full_name)
        num, name = self.extract_node_env(full_name)
        result = {
            name: {
                "node_id": config["node_id"],
                "keywords": config["keywords"],
                "children": [],
            }
        }
        return num, result

    def load_section_node(self, full_name):
        config = self.ensure_section_config(full_name)
        num, name = self.extract_node_env(full_name)
        result = {
            name: {
                "node_id": config["node_id"],
                "keywords": config["keywords"],
                "children": config.get("children", [])
            }
        }
        # if "children" in config:
        #     result["children"] = config["children"]
        return num, result

    def ensure_exercises(self, section_path):
        config = self.ensure_section_config(section_path)
        for e in config.get("export", []):
            full_name = os.path.join(section_path, e)
            exercise = load_json(full_name)
            if "exercise_id" not in exercise:
                exercise["exercise_id"] = uuid.uuid4().hex
                dump_json(full_name, exercise)

