import hashlib
import os
import secrets
from pathlib import Path

import bcrypt
import itsdangerous
import pydantic
import tomli
from fastapi import Form
from fastapi import HTTPException
from fastapi import Request
from itsdangerous import URLSafeTimedSerializer
from loguru import logger

from app.utils.emoji import _load_emojis

ROOT_DIR = Path().parent.resolve()

_CONFIG_FILE = os.getenv("MICROBLOGPUB_CONFIG_FILE", "profile.toml")

VERSION_COMMIT = "dev"

try:
    from app._version import VERSION_COMMIT  # type: ignore
except ImportError:
    pass

# Force reloading cache when the CSS is updated
CSS_HASH = "none"
try:
    css_data = (ROOT_DIR / "app" / "static" / "css" / "main.css").read_bytes()
    CSS_HASH = hashlib.md5(css_data, usedforsecurity=False).hexdigest()
except FileNotFoundError:
    pass


VERSION = f"2.0.0+{VERSION_COMMIT}"
USER_AGENT = f"microblogpub/{VERSION}"
AP_CONTENT_TYPE = "application/activity+json"


class _PrivacyReplace(pydantic.BaseModel):
    domain: str
    replace_by: str


class _ProfileMetadata(pydantic.BaseModel):
    key: str
    value: str


class _BlockedServer(pydantic.BaseModel):
    hostname: str
    reason: str | None = None


class Config(pydantic.BaseModel):
    domain: str
    username: str
    admin_password: bytes
    name: str
    summary: str
    https: bool
    icon_url: str
    secret: str
    debug: bool = False
    trusted_hosts: list[str] = ["127.0.0.1"]
    manually_approves_followers: bool = False
    privacy_replace: list[_PrivacyReplace] | None = None
    metadata: list[_ProfileMetadata] | None = None
    code_highlighting_theme = "friendly_grayscale"
    blocked_servers: list[_BlockedServer] = []

    inbox_retention_days: int = 15

    # Config items to make tests easier
    sqlalchemy_database: str | None = None
    key_path: str | None = None


def load_config() -> Config:
    try:
        return Config.parse_obj(
            tomli.loads((ROOT_DIR / "data" / _CONFIG_FILE).read_text())
        )
    except FileNotFoundError:
        raise ValueError(
            f"Please run the configuration wizard, {_CONFIG_FILE} is missing"
        )


def is_activitypub_requested(req: Request) -> bool:
    accept_value = req.headers.get("accept")
    if not accept_value:
        return False
    for val in {
        "application/ld+json",
        "application/activity+json",
    }:
        if accept_value.startswith(val):
            return True

    return False


def verify_password(pwd: str) -> bool:
    return bcrypt.checkpw(pwd.encode(), CONFIG.admin_password)


CONFIG = load_config()
DOMAIN = CONFIG.domain
_SCHEME = "https" if CONFIG.https else "http"
ID = f"{_SCHEME}://{DOMAIN}"
USERNAME = CONFIG.username
MANUALLY_APPROVES_FOLLOWERS = CONFIG.manually_approves_followers
PRIVACY_REPLACE = None
if CONFIG.privacy_replace:
    PRIVACY_REPLACE = {pr.domain: pr.replace_by for pr in CONFIG.privacy_replace}

BLOCKED_SERVERS = {blocked_server.hostname for blocked_server in CONFIG.blocked_servers}

INBOX_RETENTION_DAYS = CONFIG.inbox_retention_days

BASE_URL = ID
DEBUG = CONFIG.debug
DB_PATH = CONFIG.sqlalchemy_database or ROOT_DIR / "data" / "microblogpub.db"
SQLALCHEMY_DATABASE_URL = f"sqlite:///{DB_PATH}"
KEY_PATH = (
    (ROOT_DIR / CONFIG.key_path) if CONFIG.key_path else ROOT_DIR / "data" / "key.pem"
)
EMOJIS = "😺 😸 😹 😻 😼 😽 🙀 😿 😾"
# Emoji template for the FE
EMOJI_TPL = '<img src="/static/twemoji/{filename}.svg" alt="{raw}" class="emoji">'

_load_emojis(ROOT_DIR, BASE_URL)

CODE_HIGHLIGHTING_THEME = CONFIG.code_highlighting_theme


session_serializer = URLSafeTimedSerializer(
    CONFIG.secret,
    salt=f"{ID}.session",
)
csrf_serializer = URLSafeTimedSerializer(
    CONFIG.secret,
    salt=f"{ID}.csrf",
)


def generate_csrf_token() -> str:
    return csrf_serializer.dumps(secrets.token_hex(16))  # type: ignore


def verify_csrf_token(csrf_token: str = Form()) -> None:
    try:
        csrf_serializer.loads(csrf_token, max_age=1800)
    except (itsdangerous.BadData, itsdangerous.SignatureExpired):
        logger.exception("Failed to verify CSRF token")
        raise HTTPException(status_code=403, detail="CSRF error")
    return None