#!/usr/bin/python3
from flask import Flask, make_response, request
import os
import json
from pathlib import Path
app = Flask(__name__)
database_node_port = 5002
basic_path = "./files/db"

IMG_MIN, IMG_MAX = 1, 16
# Поля профиля, которые вообще могут существовать
ALLOWED_FIELDS = {"password", "first_name", "second_name", "email", "msg"}

# PATCH V4: database без auth. Даже если :38002 снова опубликуют на 0.0.0.0,
# без этого заголовка (его знают только logic/content) чужие запросы отсекаются.
INTERNAL = os.environ.get("RUSGRAM_INTERNAL", "e9b2f6d14a8c7035e1d0a6b8c4f2e7a9")


def require_internal():
    if request.headers.get("X-Internal") != INTERNAL:
        return make_response({"status": "forbidden"}, 403)
    return None


def safe_username(username):
    """Имя юзера становится именем файла в db/users/ — режем всё, что уводит
    запись/чтение за пределы каталога."""
    if not username or len(username) > 64:
        return False
    if "/" in username or "\\" in username or username in (".", ".."):
        return False
    if "\x00" in username or any(ord(c) < 0x20 for c in username):
        return False
    return True


def user_path(username):
    return os.path.join(basic_path, "users", username)


@app.route('/users/<string:username>/<string:field>', methods=["GET", "POST"])
def users(username, field):
    denied = require_internal()
    if denied is not None:
        return denied
    if not safe_username(username) or field not in ALLOWED_FIELDS:
        return make_response({"status": "bad_request"}, 400)
    path = user_path(username)

    if request.method == 'GET':
        if not os.path.exists(path):
            return make_response({"status": "user_not_found"}, 404)
        try:
            with open(path, "r") as f:
                data = json.loads(f.read())
        except (OSError, json.JSONDecodeError):
            return make_response({"status": "error"}, 500)
        if not isinstance(data, dict) or field not in data:
            return make_response({"status": "field_not_found"}, 404)
        return make_response({"status": "ok", "data": data[field]}, 200)

    elif request.method == "POST":
        body = request.get_json(silent=True)
        if not isinstance(body, dict) or "value" not in body:
            return make_response({"status": "bad_request"}, 400)
        value = body["value"]
        if not isinstance(value, str) or len(value) > 4096:
            return make_response({"status": "bad_request"}, 400)

        existed = os.path.exists(path)
        if not existed:
            Path(path).touch()
        try:
            with open(path, "r") as f:
                data = json.loads(f.read())
        except (OSError, json.JSONDecodeError):
            data = {}
        if not isinstance(data, dict):
            data = {}

        # PATCH V2 (defense in depth): пароль можно только СОЗДАТЬ при регистрации,
        # но не перезаписать. Функции смены пароля в сервисе нет, поэтому легальный
        # флоу это не ломает, а прямой захват аккаунта через :38002 — закрывает.
        if field == "password" and "password" in data:
            return make_response({"status": "user_exists"}, 409)

        data[field] = value
        try:
            with open(path, "w") as f:
                f.write(json.dumps(data))
        except OSError:
            return make_response({"status": "error"}, 500)
        return make_response({"status": "ok"}, 200)


@app.route('/images/<string:id>', methods=["GET", "POST"])
def images(id):
    denied = require_internal()
    if denied is not None:
        return denied
    # PATCH V8: раньше любой нечисловой/несуществующий id давал 500
    try:
        img_id = int(id)
    except (TypeError, ValueError):
        return make_response({"status": "bad_request"}, 400)
    if not (IMG_MIN <= img_id <= IMG_MAX):
        return make_response({"status": "not_found"}, 404)
    path = os.path.join(basic_path, "images", str(img_id).zfill(2))

    if request.method == 'GET':
        try:
            with open(path, "r") as f:
                data = json.loads(f.read())
        except (OSError, json.JSONDecodeError):
            return make_response({"status": "error"}, 500)
        return make_response({"status": "ok", "data": data}, 200)

    elif request.method == "POST":
        body = request.get_json(silent=True)
        if not isinstance(body, dict) or "value" not in body:
            return make_response({"status": "bad_request"}, 400)
        value = body["value"]
        if (not isinstance(value, list) or len(value) != 2
                or not all(isinstance(x, str) for x in value)
                or len(value[1]) > 4096):
            return make_response({"status": "bad_request"}, 400)
        try:
            with open(path, "r") as f:
                data = json.loads(f.read())
            if not isinstance(data, dict) or not isinstance(data.get("comments"), list):
                return make_response({"status": "error"}, 500)
            data["comments"].append(value)
            with open(path, "w") as f:
                f.write(json.dumps(data))
        except (OSError, json.JSONDecodeError):
            return make_response({"status": "error"}, 500)
        return make_response({"status": "ok"}, 200)


if __name__ == '__main__':
    app.run(host="0.0.0.0", port=database_node_port)