use clap::{
    app_from_crate, crate_authors, crate_description, crate_name, crate_version, App, Arg,
    ArgMatches, SubCommand,
};
use diesel::prelude::*;
use dotenv::dotenv;
use std::{
    io::{self, BufRead, Write},
    path::PathBuf,
};

use crate::{models::NewUser, ServerConfig, ServerError};
use crate::{queries, schema};

use slog::{Drain, Logger};

fn generate_cli() -> App<'static, 'static> {
    app_from_crate!()
        .arg(
            Arg::with_name("database")
                .long("db")
                .help("The path of the sqlite database")
                .env("PSLINK_DATABASE")
                .default_value("links.db")
                .global(true),
        )
        .arg(
            Arg::with_name("port")
                .long("port")
                .short("p")
                .help("The port the pslink service will run on")
                .env("PSLINK_PORT")
                .default_value("8080")
                .global(true),
        )
        .arg(
            Arg::with_name("public_url")
                .long("public-url")
                .short("u")
                .help("The host url or the page that will be part of the short urls.")
                .env("PSLINK_PUBLIC_URL")
                .default_value("localhost:8080")
                .global(true),
        )
        .arg(
            Arg::with_name("internal_ip")
                .long("hostip")
                .short("i")
                .help("The host (ip) that will run the pslink service")
                .env("PSLINK_IP")
                .default_value("localhost")
                .global(true),
        )
        .arg(
            Arg::with_name("protocol")
                .long("protocol")
                .short("t")
                .help(concat!(
                    "The protocol that is used in the qr-codes",
                    " (http results in slightly smaller codes in some cases)"
                ))
                .env("PSLINK_PROTOCOL")
                .default_value("http")
                .possible_values(&["http", "https"])
                .global(true),
        )
        .arg(
            Arg::with_name("secret")
                .long("secret")
                .help(concat!(
                    "The secret that is used to encrypt the",
                    " password database keep this as inacessable as possible.",
                    " As commandlineparameters are visible",
                    " to all users",
                    " it is not wise to use this as",
                    " a commandline parameter but rather as an environment variable.",
                ))
                .env("PSLINK_SECRET")
                .default_value("")
                .global(true),
        )
        .subcommand(
            SubCommand::with_name("runserver")
                .about("Run the server")
                .display_order(1),
        )
        .subcommand(
            SubCommand::with_name("migrate-database")
                .about("Apply any pending migrations and exit")
                .display_order(2),
        )
        .subcommand(
            SubCommand::with_name("generate-env")
                .about("Generate an .env file template using default settings and exit")
                .display_order(2),
        )
        .subcommand(
            SubCommand::with_name("create-admin")
                .about("Create an admin user.")
                .display_order(2),
        )
}

fn parse_args_to_config(config: &ArgMatches, log: &Logger) -> ServerConfig {
    let secret = config
        .value_of("secret")
        .expect("Failed to read the secret")
        .to_owned();
    let secret = if secret.len() < 5 {
        use rand::distributions::Alphanumeric;
        use rand::{thread_rng, Rng};

        if secret.is_empty() {
            slog_warn!(
                log,
                "No secret was found! Use the environment variable PSLINK_SECRET to set one."
            );
            slog_warn!(
                log,
                "If you change the secret all passwords will be invalid"
            );
            slog_warn!(log, "Using an auto generated one for this run.");
        } else {
            slog_warn!(
                log,
                "The provided secret was too short. Using an autogenerated one."
            )
        }

        thread_rng()
            .sample_iter(&Alphanumeric)
            .take(30)
            .map(char::from)
            .collect()
    } else {
        secret
    };
    let db = config
        .value_of("database")
        .expect(concat!(
            "Neither the DATABASE_URL environment variable",
            " nor the commandline parameters",
            " contain a valid database location."
        ))
        .parse::<PathBuf>()
        .expect("Failed to parse Database path.");
    let public_url = config
        .value_of("public_url")
        .expect("Failed to read the host value")
        .to_owned();
    let internal_ip = config
        .value_of("internal_ip")
        .expect("Failed to read the host value")
        .to_owned();
    let port = config
        .value_of("port")
        .expect("Failed to read the port value")
        .parse::<u32>()
        .expect("Failed to parse the portnumber");
    let protocol = config
        .value_of("protocol")
        .expect("Failed to read the protocol value")
        .parse::<crate::Protocol>()
        .expect("Failed to parse the protocol");

    let log = log.new(slog_o!("host" => public_url.clone()));

    crate::ServerConfig {
        secret,
        db,
        public_url,
        internal_ip,
        port,
        protocol,
        log,
    }
}

pub(crate) fn setup() -> Result<Option<crate::ServerConfig>, ServerError> {
    dotenv().ok();

    let decorator = slog_term::TermDecorator::new().build();
    let drain = slog_term::FullFormat::new(decorator).build().fuse();
    let drain = slog_async::Async::new(drain).build().fuse();

    let log = slog::Logger::root(drain, slog_o!("name" => "Pslink"));

    slog_info!(log, "Launching Pslink a 'Private short link generator'");
    slog_info!(log, ".env file setup, logging initialized");

    let app = generate_cli();
    let config = app.get_matches();

    let server_config: crate::ServerConfig = parse_args_to_config(&config, &log);

    if let Some(_migrate_config) = config.subcommand_matches("generate-env") {
        return match generate_env_file(&server_config) {
            Ok(_) => Ok(None),
            Err(e) => Err(e),
        };
    }
    if let Some(_migrate_config) = config.subcommand_matches("migrate-database") {
        return match apply_migrations(&server_config) {
            Ok(_) => Ok(None),
            Err(e) => Err(e),
        };
    }
    if let Some(_create_config) = config.subcommand_matches("create-admin") {
        return match create_admin(&server_config) {
            Ok(_) => Ok(None),
            Err(e) => Err(e),
        };
    }

    if let Some(_runserver_config) = config.subcommand_matches("runserver") {
        let connection = if server_config.db.exists() {
            queries::establish_connection(&server_config.db)?
        } else {
            let msg = format!(
                concat!(
                    "Database not found at {}!",
                    " Create a new database with: `pslink migrate-database`",
                    "or adjust the databasepath."
                ),
                server_config.db.display()
            );
            slog_error!(&server_config.log, "{}", msg);
            eprintln!("{}", msg);
            return Ok(None);
        };
        let num_users: i64 = schema::users::dsl::users
            .filter(schema::users::dsl::role.eq(2))
            .select(diesel::dsl::count_star())
            .first(&connection)
            .expect("Failed to count the users");

        if num_users < 1 {
            slog_warn!(
                &server_config.log,
                concat!(
                    "No user created you will not be",
                    " able to do anything as the service is invite only.",
                    " Create a user with `pslink create-admin`"
                )
            );
        }
        slog_info!(
            &server_config.log,
            "Initialization finished starting the service."
        );
        Ok(Some(server_config))
    } else {
        println!("{}", config.usage());
        Err(ServerError::User("Print usage.".into()))
    }
}

fn create_admin(config: &ServerConfig) -> Result<(), ServerError> {
    use schema::users;
    use schema::users::dsl::{id, role};
    slog_info!(&config.log, "Creating an admin user.");
    let sin = io::stdin();

    let connection = queries::establish_connection(&config.db)?;

    // wait for logging:
    std::thread::sleep(std::time::Duration::from_millis(100));

    print!("Please enter the Username of the admin: ");
    io::stdout().flush().unwrap();
    let new_username = sin.lock().lines().next().unwrap().unwrap();

    print!("Please enter the emailadress for {}: ", new_username);
    io::stdout().flush().unwrap();
    let email = sin.lock().lines().next().unwrap().unwrap();

    print!("Please enter the password for {}: ", new_username);
    io::stdout().flush().unwrap();
    let password = rpassword::read_password().unwrap();
    slog_info!(
        &config.log,
        "Creating {} ({}) with given password ",
        &new_username,
        &email
    );

    let new_admin = NewUser::new(new_username, email, &password, config)?;

    diesel::insert_into(users::table)
        .values(&new_admin)
        .execute(&connection)?;

    // Add admin rights to the first user (which should be the only one)
    diesel::update(users::dsl::users.filter(id.eq(&1)))
        .set((role.eq(2),))
        .execute(&connection)?;
    slog_info!(&config.log, "Admin user created: {}", &new_admin.username);
    Ok(())
}

fn apply_migrations(config: &ServerConfig) -> Result<(), ServerError> {
    slog_info!(
        config.log,
        "Creating a database file and running the migrations:"
    );
    let connection = queries::establish_connection(&config.db)?;
    crate::embedded_migrations::run_with_output(&connection, &mut std::io::stdout())?;
    Ok(())
}

fn generate_env_file(server_config: &ServerConfig) -> Result<(), ServerError> {
    if std::path::Path::new(".env").exists() {
        slog_error!(
            server_config.log,
            "ERROR: There already is a .env file - ABORT!"
        )
    } else {
        slog_info!(
            server_config.log,
            "Creating a .env file with default options"
        );
        slog_info!(
            server_config.log,
            concat!(
                "The SECRET_KEY variable is used for password encryption.",
                "If it is changed all existing passwords are invalid."
            )
        );
        let mut file = std::fs::File::create(".env")?;

        let conf_file_content = server_config.to_env_strings();

        conf_file_content.iter().for_each(|l| {
            file.write_all(l.as_bytes())
                .expect("failed to write .env file")
        });
        slog_info!(server_config.log, "Successfully created the env file!")
    }
    Ok(())
}