/*
 ** Copyright (C) 2021 KunoiSayami
 **
 ** This file is part of cgit-simple-authentication and is released under
 ** the AGPL v3 License: https://www.gnu.org/licenses/agpl-3.0.txt
 **
 ** This program is free software: you can redistribute it and/or modify
 ** it under the terms of the GNU Affero General Public License as published by
 ** the Free Software Foundation, either version 3 of the License, or
 ** any later version.
 **
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 ** GNU Affero General Public License for more details.
 **
 ** You should have received a copy of the GNU Affero General Public License
 ** along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

use sha2::Digest;
use anyhow::Result;
use url::form_urlencoded;
use std::borrow::Cow;
use std::path::Path;
use std::fs::read_to_string;
use std::convert::TryFrom;

const DEFAULT_CONFIG_LOCATION: &str = "/etc/cgitrc";
const DEFAULT_COOKIE_TTL: usize = 1200;
const DEFAULT_DATABASE_LOCATION: &str = "/etc/cgit/auth.db";

#[derive(Debug, Clone)]
pub struct Config {
    pub cookie_ttl: usize,
    database: String,
}

impl Default for Config {
    fn default() -> Self {
        Self {
            cookie_ttl: DEFAULT_COOKIE_TTL,
            database: DEFAULT_DATABASE_LOCATION.to_string(),
        }
    }
}

impl Config {
    pub fn new() -> Self {
        Self::load_from_path(DEFAULT_CONFIG_LOCATION)
    }

    pub fn load_from_path<P: AsRef<Path>>(path: P) -> Self {
        let file = read_to_string(path).unwrap_or_default();
        let mut cookie_ttl: usize = DEFAULT_COOKIE_TTL;
        let mut database: &str = "/etc/cgit/auth.db";
        for line in file.lines() {

            let line = line.trim();
            if !line.contains('=') || !line.starts_with("cgit-simple-auth-") {
                continue
            }

            let (key, value) = if line.contains('#') {
                line.split_once('#').unwrap().0.split_once('=').unwrap()
            } else {
                line.split_once('=').unwrap()
            };
            let key_name = key.split_once("auth-").unwrap().1;
            match key_name {
                "cookie-ttl" => cookie_ttl = usize::try_from(value).unwrap_or(DEFAULT_COOKIE_TTL),
                "database" => database = value,
                _ => {}
            }
        }
        Self {
            cookie_ttl,
            database: database.to_string()
        }
    }

    pub fn get_database_location(&self) -> &str {
        self.database.as_str()
    }
}


#[derive(Debug, Clone, Default)]
pub struct FormData {
    user: String,
    password: String,
    hash: String,
}

impl FormData {
    pub fn new() -> Self {
        Self { ..Default::default()}
    }

    pub fn set_password(&mut self, password: String) {
        self.password = password;
        self.hash = Default::default();
    }

    pub fn set_user(&mut self, user: String) {
        self.user = user
    }

    pub fn get_user(&self) -> &String {
        &self.user
    }

    pub fn get_password_sha256(&self) -> Result<String> {
        let mut hasher = sha2::Sha256::new();
        hasher.update(self.password.as_bytes());
        Ok(format!("{:x}", hasher.finalize()))
    }

    #[allow(dead_code)]
    pub fn get_password_sha256_cache(&mut self) -> Result<String> {
        if self.hash.len() == 0 {
            self.hash = self.get_password_sha256()?;
        }
        Ok(self.hash.clone())
    }
}

impl From<&[u8]> for FormData {
    fn from(input: &[u8]) -> Self {
        let fields = form_urlencoded::parse(input);
        let mut data = Self::new();
        for f in fields {
            match f.0 {
                Cow::Borrowed("username") => {
                    data.set_user(f.1.to_string());
                }
                Cow::Borrowed("password") => {
                    data.set_password(f.1.to_string());
                    data.get_password_sha256_cache().unwrap();
                }
                _ => {}
            }
        }
        data
    }
}

impl From<&String> for FormData {
    fn from(s: &String) -> Self {
        Self::from(s.as_bytes())
    }
}

impl From<String> for FormData {
    fn from(s: String) -> Self {
        Self::from(&s)
    }
}