use std::{
    io,
    process::{Command, Output},
};

use log::{info, warn};
use peach_lib::sbot::{SbotConfig, SbotStatus};
use rocket::{
    form::{Form, FromForm},
    get, post,
    request::FlashMessage,
    response::{Flash, Redirect},
};
use rocket_dyn_templates::{tera::Context, Template};

use crate::routes::authentication::Authenticated;
use crate::utils;

#[derive(Debug, FromForm)]
pub struct SbotConfigForm {
    /// Directory path for the log and indexes.
    repo: String,
    /// Directory path for writing debug output.
    debugdir: String,
    /// Secret-handshake app-key (aka. network key).
    shscap: String,
    /// HMAC hash used to sign messages.
    hmac: String,
    /// Replication hops (1: friends, 2: friends of friends).
    hops: u8,
    /// IP address to listen on.
    lis_ip: String,
    /// Port to listen on.
    lis_port: String,
    /// Address to listen on for WebSocket connections.
    wslis: String,
    /// Address to for metrics and pprof HTTP server.
    debuglis: String,
    /// Enable sending local UDP broadcasts.
    localadv: bool,
    /// Enable listening for UDP broadcasts and connecting.
    localdiscov: bool,
    /// Enable syncing by using epidemic-broadcast-trees (EBT).
    enable_ebt: bool,
    /// Bypass graph auth and fetch remote's feed (useful for pubs that are restoring their data
    /// from peer; user beware - caveats about).
    promisc: bool,
    /// Disable the UNIX socket RPC interface.
    nounixsock: bool,
    /// Run the go-sbot on system start-up (systemd service enabled).
    startup: bool,
    /// Attempt to repair the filesystem before starting.
    repair: bool,
}

// HELPERS AND ROUTES FOR /settings/scuttlebutt

/// Scuttlebutt settings menu.
#[get("/")]
pub fn ssb_settings_menu(flash: Option<FlashMessage>, _auth: Authenticated) -> Template {
    // retrieve current ui theme
    let theme = utils::get_theme();

    // retrieve go-sbot systemd process status
    let sbot_status = SbotStatus::read().ok();

    let mut context = Context::new();
    context.insert("theme", &theme);
    context.insert("sbot_status", &sbot_status);
    context.insert("back", &Some("/settings".to_string()));
    context.insert("title", &Some("Scuttlebutt Settings".to_string()));

    if let Some(flash) = flash {
        context.insert("flash_name", &Some(flash.kind().to_string()));
        context.insert("flash_msg", &Some(flash.message().to_string()));
    };

    Template::render("settings/scuttlebutt/menu", &context.into_json())
}

/// Sbot configuration page (includes form for updating configuration parameters).
#[get("/configure")]
pub fn configure_sbot(flash: Option<FlashMessage>, _auth: Authenticated) -> Template {
    // retrieve current ui theme
    let theme = utils::get_theme();

    // retrieve go-sbot systemd process status
    let sbot_status = SbotStatus::read().ok();
    let run_on_startup = sbot_status.map(|status| status.boot_state);

    // retrieve sbot config parameters
    let sbot_config = SbotConfig::read().ok();

    let mut context = Context::new();
    context.insert("theme", &theme);
    context.insert("back", &Some("/settings/scuttlebutt".to_string()));
    context.insert("title", &Some("Sbot Configuration".to_string()));
    context.insert("sbot_config", &sbot_config);
    context.insert("run_on_startup", &Some(run_on_startup));

    if let Some(flash) = flash {
        context.insert("flash_name", &Some(flash.kind().to_string()));
        context.insert("flash_msg", &Some(flash.message().to_string()));
    };

    Template::render("settings/scuttlebutt/configure_sbot", &context.into_json())
}

// TODO: consider using `Contextual` here to collect all submitted form
// fields to re-render forms with submitted values on error

/// Receive the sbot configuration form data and save it to file.
#[post("/configure?<restart>", data = "<config>")]
pub fn configure_sbot_post(
    restart: bool,
    config: Form<SbotConfigForm>,
    _auth: Authenticated,
) -> Flash<Redirect> {
    // call `into_inner()` to take ownership of the `config` data
    let owned_config = config.into_inner();

    // concat the ip and port for listen address
    let lis = format!("{}:{}", owned_config.lis_ip, owned_config.lis_port);

    // instantiate `SbotConfig` from form data
    let config = SbotConfig {
        lis,
        hops: owned_config.hops,
        repo: owned_config.repo,
        debugdir: owned_config.debugdir,
        shscap: owned_config.shscap,
        localadv: owned_config.localadv,
        localdiscov: owned_config.localdiscov,
        hmac: owned_config.hmac,
        wslis: owned_config.wslis,
        debuglis: owned_config.debuglis,
        enable_ebt: owned_config.enable_ebt,
        promisc: owned_config.promisc,
        nounixsock: owned_config.nounixsock,
        repair: owned_config.repair,
    };

    match owned_config.startup {
        true => {
            info!("Enabling go-sbot.service");
            if let Err(e) = systemctl_sbot_cmd("enable") {
                warn!("Failed to enable go-sbot.service: {}", e)
            }
        }
        false => {
            info!("Disabling go-sbot.service");
            if let Err(e) = systemctl_sbot_cmd("disable") {
                warn!("Failed to disable go-sbot.service: {}", e)
            }
        }
    };

    // write config to file
    match SbotConfig::write(config) {
        Ok(_) => {
            // if `restart` query parameter is `true`, attempt sbot process (re)start
            if restart {
                restart_sbot_process(
                    // redirect url
                    "/settings/scuttlebutt/configure",
                    // success flash msg
                    "Updated configuration and restarted the sbot process",
                    // first failed flash msg
                    "Updated configuration but failed to start the sbot process",
                    // second failed flash msg
                    "Updated configuration but failed to stop the sbot process",
                )
            } else {
                Flash::success(
                    Redirect::to("/settings/scuttlebutt/configure"),
                    "Updated configuration",
                )
            }
        }
        Err(e) => Flash::error(
            Redirect::to("/settings/scuttlebutt/configure"),
            format!("Failed to update configuration: {}", e),
        ),
    }
}

/// Set default configuration parameters for the go-sbot and save them to file.
#[get("/configure/default")]
pub fn configure_sbot_default(_auth: Authenticated) -> Flash<Redirect> {
    let default_config = SbotConfig::default();

    // write default config to file
    match SbotConfig::write(default_config) {
        Ok(_) => Flash::success(
            Redirect::to("/settings/scuttlebutt/configure"),
            "Restored default configuration",
        ),
        Err(e) => Flash::error(
            Redirect::to("/settings/scuttlebutt/configure"),
            format!("Failed to restore default configuration: {}", e),
        ),
    }
}

/// Attempt to start the go-sbot.service process.
/// Redirect to the Scuttlebutt settings menu and communicate the outcome of
/// the attempt via a flash message.
#[get("/start")]
pub fn start_sbot(_auth: Authenticated) -> Flash<Redirect> {
    info!("Starting go-sbot.service");
    match systemctl_sbot_cmd("start") {
        Ok(_) => Flash::success(
            Redirect::to("/settings/scuttlebutt"),
            "Sbot process has been started",
        ),
        Err(_) => Flash::error(
            Redirect::to("/settings/scuttlebutt"),
            "Failed to start the sbot process",
        ),
    }
}

/// Attempt to stop the go-sbot.service process.
/// Redirect to the Scuttlebutt settings menu and communicate the outcome of
/// the attempt via a flash message.
#[get("/stop")]
pub fn stop_sbot(_auth: Authenticated) -> Flash<Redirect> {
    info!("Stopping go-sbot.service");
    match systemctl_sbot_cmd("stop") {
        Ok(_) => Flash::success(
            Redirect::to("/settings/scuttlebutt"),
            "Sbot process has been stopped",
        ),
        Err(_) => Flash::error(
            Redirect::to("/settings/scuttlebutt"),
            "Failed to stop the sbot process",
        ),
    }
}

/// Attempt to restart the go-sbot.service process.
/// Redirect to the Scuttlebutt settings menu and communicate the outcome of
/// the attempt via a flash message.
#[get("/restart")]
pub fn restart_sbot(_auth: Authenticated) -> Flash<Redirect> {
    restart_sbot_process(
        "/settings/scuttlebutt",
        "Sbot process has been restarted",
        "Failed to start the sbot process",
        "Failed to stop the sbot process",
    )
}

// HELPER FUNCTIONS

/// Executes a systemctl command for the go-sbot.service process.
pub fn systemctl_sbot_cmd(cmd: &str) -> io::Result<Output> {
    Command::new("systemctl")
        .arg("--user")
        .arg(cmd)
        .arg("go-sbot.service")
        .output()
}

/// Executes a systemctl stop command followed by start command.
/// Returns a redirect with a flash message stating the output of the restart attempt.
fn restart_sbot_process(
    redirect_url: &str,
    success_msg: &str,
    start_failed_msg: &str,
    stop_failed_msg: &str,
) -> Flash<Redirect> {
    let url = redirect_url.to_string();

    info!("Restarting go-sbot.service");
    match systemctl_sbot_cmd("stop") {
        // if stop was successful, try to start the process
        Ok(_) => match systemctl_sbot_cmd("start") {
            Ok(_) => Flash::success(Redirect::to(url), success_msg),

            Err(e) => Flash::error(Redirect::to(url), format!("{}: {}", start_failed_msg, e)),
        },
        Err(e) => Flash::error(Redirect::to(url), format!("{}: {}", stop_failed_msg, e)),
    }
}