use crate::{
    routes::ui::{
        account::session::AdminSession,
        error::MyResult,
        layout::{DynLayoutPage, LayoutPage},
    },
    uri,
};
use log::Level;
use rocket::get;
use std::{
    collections::VecDeque,
    fmt::Write,
    sync::{LazyLock, RwLock},
};

const MAX_LOG_LEN: usize = 4000;

static LOGGER: LazyLock<Log> = LazyLock::new(Log::new);

pub fn enable_logging() {
    log::set_logger(&*LOGGER).unwrap();
    log::set_max_level(log::LevelFilter::Debug);
}

pub struct Log {
    inner: env_logger::Logger,
    log: RwLock<(VecDeque<LogLine>, VecDeque<LogLine>)>,
}

pub struct LogLine {
    module: Option<&'static str>,
    level: Level,
    message: String,
}

#[get("/admin/log?<warnonly>")]
pub fn r_admin_log<'a>(_session: AdminSession, warnonly: bool) -> MyResult<DynLayoutPage<'a>> {
    Ok(LayoutPage {
        title: "Log".into(),
        content: markup::new! {
            h1 { "Server Log" }
            a[href=uri!(r_admin_log(!warnonly))] { @if warnonly { "Show everything" } else { "Show only warnings" }}
            code.log {
                @let g = LOGGER.log.read().unwrap();
                table { @for e in if warnonly { g.1.iter() } else { g.0.iter() } {
                    tr[class=format!("level-{:?}", e.level).to_ascii_lowercase()] {
                        td { @format_level(e.level) }
                        td { @e.module }
                        td { @markup::raw(vt100_to_html(&e.message)) }
                    }
                }}
            }
        },
        ..Default::default()
    })
}

impl Log {
    pub fn new() -> Self {
        Self {
            inner: env_logger::builder()
                .filter_level(log::LevelFilter::Warn)
                .parse_env("LOG")
                .build(),
            log: Default::default(),
        }
    }
    fn should_log(&self, metadata: &log::Metadata) -> bool {
        let level = metadata.level();
        level
            <= match metadata.target() {
                x if x.starts_with("jellything::") => Level::Debug,
                x if x.starts_with("rocket::") => Level::Info,
                _ => Level::Warn,
            }
    }
    fn do_log(&self, record: &log::Record) {
        let mut w = self.log.write().unwrap();
        w.0.push_back(LogLine {
            module: record.module_path_static(),
            level: record.level(),
            message: record.args().to_string(),
        });
        while w.0.len() > MAX_LOG_LEN {
            w.0.pop_front();
        }
        if record.level() <= Level::Warn {
            w.1.push_back(LogLine {
                module: record.module_path_static(),
                level: record.level(),
                message: record.args().to_string(),
            });
            while w.1.len() > MAX_LOG_LEN {
                w.1.pop_front();
            }
        }
    }
}

impl log::Log for Log {
    fn enabled(&self, metadata: &log::Metadata) -> bool {
        self.inner.enabled(metadata) || self.should_log(metadata)
    }
    fn log(&self, record: &log::Record) {
        match (record.module_path_static(), record.line()) {
            // TODO is there a better way to ignore those?
            (Some("rocket::rocket"), Some(670)) => return,
            (Some("rocket::server"), Some(401)) => return,
            _ => {}
        }
        if self.inner.enabled(record.metadata()) {
            self.inner.log(record);
        }
        if self.should_log(record.metadata()) {
            self.do_log(record)
        }
    }
    fn flush(&self) {
        self.inner.flush();
    }
}

fn vt100_to_html(s: &str) -> String {
    let mut out = HtmlOut::default();
    let mut st = vte::Parser::new();
    for b in s.bytes() {
        st.advance(&mut out, b);
    }
    out.s
}

fn format_level(level: Level) -> impl markup::Render {
    let (s, c) = match level {
        Level::Debug => ("DEBUG", "blue"),
        Level::Error => ("ERROR", "red"),
        Level::Warn => ("WARN", "yellow"),
        Level::Info => ("INFO", "green"),
        Level::Trace => ("TRACE", "lightblue"),
    };
    markup::new! { span[style=format!("color:{c}")] {@s} }
}

pub struct HtmlOut {
    s: String,
    color: bool,
}
impl Default for HtmlOut {
    fn default() -> Self {
        Self {
            color: false,
            s: String::new(),
        }
    }
}
impl HtmlOut {
    pub fn set_color(&mut self, [r, g, b]: [u8; 3]) {
        self.reset_color();
        self.color = true;
        write!(self.s, "<span style=color:#{:02x}{:02x}{:02x}>", r, g, b).unwrap()
    }
    pub fn reset_color(&mut self) {
        if self.color {
            write!(self.s, "</span>").unwrap();
            self.color = false;
        }
    }
}
impl vte::Perform for HtmlOut {
    fn print(&mut self, c: char) {
        match c {
            'a'..='z' | 'A'..='Z' | '0'..='9' | ' ' => self.s.push(c),
            x => write!(self.s, "&#{};", x as u32).unwrap(),
        }
    }

    fn execute(&mut self, _byte: u8) {}
    fn hook(&mut self, _params: &vte::Params, _i: &[u8], _ignore: bool, _a: char) {}
    fn put(&mut self, _byte: u8) {}
    fn unhook(&mut self) {}
    fn osc_dispatch(&mut self, _params: &[&[u8]], _bell_terminated: bool) {}
    fn esc_dispatch(&mut self, _intermediates: &[u8], _ignore: bool, _byte: u8) {
        // self.s += &format!(" {:?} ", (_intermediates, _byte))
    }

    fn csi_dispatch(
        &mut self,
        params: &vte::Params,
        _intermediates: &[u8],
        _ignore: bool,
        action: char,
    ) {
        let mut k = params.iter();
        // self.s += &format!(" {:?} ", (params, action));
        match action {
            'm' => match k.next().unwrap_or(&[0]).get(0).unwrap_or(&0) {
                c @ (30..=37 | 40..=47) => {
                    let c = if *c >= 40 { *c - 10 } else { *c };
                    self.set_color(match c {
                        30 => [0, 0, 0],
                        31 => [255, 0, 0],
                        32 => [0, 255, 0],
                        33 => [255, 255, 0],
                        34 => [0, 0, 255],
                        35 => [255, 0, 255],
                        36 => [0, 255, 255],
                        37 => [255, 255, 255],
                        _ => unreachable!(),
                    });
                }
                _ => (),
            },
            _ => (),
        }
    }
}