use std::process;
use std::time::{Duration, SystemTime, UNIX_EPOCH};

use chrono::Duration as ChronoDuration;
use serenity::framework::standard::macros::command;
use serenity::framework::standard::CommandResult;
use serenity::model::channel::Message;
use serenity::prelude::*;
use sysinfo::{ProcessExt, SystemExt};

use crate::commands::common::handle_autodelete;

const VERSION: &'static str = env!("CARGO_PKG_VERSION");

#[command]
#[description("Shows some statistics about the bot")]
#[usage("")]
async fn stats(ctx: &Context, msg: &Message) -> CommandResult {
    log::debug!("Reading system stats");
    let mut system = sysinfo::System::new_all();
    system.refresh_all();
    let kernel_version = system.get_kernel_version().unwrap_or("n/a".to_string());
    let own_process = system.get_process(process::id() as i32).unwrap();
    let memory_usage = own_process.memory();
    let cpu_usage = own_process.cpu_usage();
    let thread_count = own_process.tasks.len();
    let current_user = ctx.http.get_current_user().await?;
    let guild_count: usize = current_user.guilds(ctx).await?.len();
    let bot_info = ctx.http.get_current_application_info().await?;

    let current_time_seconds = SystemTime::now().duration_since(UNIX_EPOCH).unwrap();
    let uptime = current_time_seconds - Duration::from_secs(own_process.start_time());
    let uptime = ChronoDuration::from_std(uptime).unwrap();

    let discord_info = format!(
        r#"
    Version: {}
    Owner: <@{}>
    Guilds: {}
    "#,
        VERSION, bot_info.owner.id, guild_count
    );

    log::trace!("Discord info {}", discord_info);

    let system_info = format!(
        r#"
    Kernel Version: {}
    Memory Usage: {:.2} MiB
    CPU Usage: {:.2} %
    Thread Count: {}
    Uptime: {}d {}h {}m
    "#,
        kernel_version,
        memory_usage as f64 / 1024f64,
        cpu_usage,
        thread_count,
        uptime.num_days(),
        uptime.num_hours() % 24,
        uptime.num_minutes() % 60
    );
    log::trace!("System info {}", system_info);

    msg.channel_id
        .send_message(ctx, |m| {
            m.embed(|e| {
                e.title("Bot Stats")
                    .field("Bot Information", discord_info, true)
                    .field("System information", system_info, true)
            })
        })
        .await?;
    handle_autodelete(ctx, msg).await?;

    Ok(())
}