import json
import logging
import os
import re
import sys
import uuid
import re
import git

id_set = set()
logger = logging.getLogger(__name__)
logger.setLevel(logging.INFO)
handler = logging.StreamHandler(sys.stdout)
formatter = logging.Formatter('%(asctime)s - %(levelname)s - %(message)s')
handler.setFormatter(formatter)
logger.addHandler(handler)
repo = git.Repo(".")

def user_name():
    return repo.config_reader().get_value("user", "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+', encoding="utf8") 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


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

    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 + 1}.{section_title}")
                    if os.path.isdir(full_path):
                        self.check_section_keywords(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 sort_dir_list(self, dirs):
        result = [self.extract_node_env(dir) for dir in dirs]
        result.sort(key=lambda item: item[0])
        return result

    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 = self.resort_children(self.root, levels)
        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 = self.resort_children(base, chapters)
        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 = self.resort_children(base, sections)
        chapter_node["children"] = [item[1] for item in sections]
        return chapter_node

    def resort_children(self, base, children):
        children.sort(key=lambda item: item[0])
        for index, [number, element] in enumerate(children):
            title = list(element.keys())[0]
            origin = os.path.join(base, f"{number}.{title}")
            posted = os.path.join(base, f"{index + 1}.{title}")
            if origin != posted:
                self.logger.info(f"rename [{origin}] to [{posted}]")
            os.rename(origin, posted)
        return children

    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(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_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(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_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, result, exist_ok=True, override=True)
        return config

    def ensure_node_id(self, config):
        flag = False
        if "node_id" not in config or \
                not config["node_id"].startswith(f"{self.name}-") or \
                config["node_id"] in id_set:
            new_id = self.gen_node_id()
            id_set.add(new_id)
            config["node_id"] = new_id
            flag = True

        for child in config.get("children", []):
            child_node = list(child.values())[0]
            f, _ = self.ensure_node_id(child_node)
            flag = flag or f

        return flag, config

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

    def extract_node_env(self, path):
        try:
            _, dir = os.path.split(path)
            self.logger.info(path)
            number, title = dir.split(".", 1)
            return int(number), title
        except Exception as error:
            self.logger.error(f"目录 [{path}] 解析失败，结构不合法，可能是缺少序号")
            # sys.exit(1)
            raise error

    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)
        flag = False
        for e in os.listdir(section_path):
            base, ext = os.path.splitext(e)
            _, source = os.path.split(e)
            if ext != ".md":
                continue
            mfile = base + ".json"
            meta_path = os.path.join(section_path, mfile)
            self.ensure_exercises_meta(meta_path, source)
            export = config.get("export", [])
            if mfile not in export and self.name != "algorithm":
                export.append(mfile)
                flag = True
                config["export"] = export

        if flag:
            dump_json(os.path.join(section_path, "config.json"), config, True, True)

        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 or exercise.get("exercise_id") in id_set:
                eid = uuid.uuid4().hex
                exercise["exercise_id"] = eid
                dump_json(full_name, exercise, True, True)
            else:
                id_set.add(exercise["exercise_id"])

    def ensure_exercises_meta(self, meta_path, source):
        _, mfile = os.path.split(meta_path)
        meta = None
        if os.path.exists(meta_path):
            with open(meta_path) as f:
                content = f.read()
            if content:
                meta = json.loads(content)
                if "exercise_id" not in meta:
                    meta["exercise_id"] = uuid.uuid4().hex
                if "notebook_enable" not in meta:
                    meta["notebook_enable"] = self.default_notebook()
                if "source" not in meta:
                    meta["source"] = source
                if "author" not in meta:
                    meta["author"] = user_name()
                if "type" not in meta:
                    meta["type"] = "code_options"
            if meta is None:
                meta = {
                    "type": "code_options",
                    "author": user_name(),
                    "source": source,
                    "notebook_enable": self.default_notebook(),
                    "exercise_id": uuid.uuid4().hex
                }
        dump_json(meta_path, meta, True, True)

    def default_notebook(self):
        if self.name in ["python", "java", "c"]:
            return True
        else:
            return False

    def check_section_keywords(self, full_path):
        config = self.ensure_section_config(full_path)
        if not config.get("keywords", []):
            self.logger.error(f"节点 [{full_path}] 的关键字为空，请修改配置文件写入关键字")
            sys.exit(1)
