/*
 * Copyright (C) 2023  Valentin Lorentz
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3,
 * as published by the Free Software Foundation.
 *
 * 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 std::collections::VecDeque;
use std::sync::Arc;
use std::sync::RwLock;

use matrix_sdk::async_trait;
use memuse::DynamicUsage;
use ratatui::text::Text;
use tokio::sync::mpsc::UnboundedReceiver;
use tracing_error::ErrorLayer;
use tracing_subscriber::prelude::*;

use super::{Buffer, BufferId, BufferItem, BufferItemContent, FullyReadStatus};
use crate::widgets::Prerender;

/// Maximum number of log lines to be stored in memory
const MAX_MEM_LOG_LINES: usize = 1000;

pub struct LogBuffer {
  lines: VecDeque<(u64, String, Prerender)>,
  receiver: UnboundedReceiver<String>,
}

impl LogBuffer {
  pub fn new(receiver: UnboundedReceiver<String>) -> Self {
    LogBuffer {
      lines: VecDeque::new(),
      receiver,
    }
  }
}

impl DynamicUsage for LogBuffer {
  fn dynamic_usage(&self) -> usize {
    self.lines.dynamic_usage()
  }
  fn dynamic_usage_bounds(&self) -> (usize, Option<usize>) {
    self.lines.dynamic_usage_bounds()
  }
}

#[async_trait]
impl Buffer for LogBuffer {
  fn short_name(&self) -> String {
    "ratatrix".to_owned()
  }

  fn id(&self) -> BufferId {
    BufferId::Log
  }

  async fn poll_updates_once(&mut self) {
    let line = self
      .receiver
      .recv()
      .await
      .expect("LogBuffer's channel was closed");
    if self.lines.len() >= MAX_MEM_LOG_LINES {
      self.lines.pop_front();
    }
    let line_id = self
      .lines
      .back()
      .map(|(last_id, _, _)| last_id + 1)
      .unwrap_or(0);
    self.lines.push_back((line_id, line, Prerender::new()));
  }

  fn content<'a>(&'a self) -> Box<dyn ExactSizeIterator<Item = BufferItem<'a>> + 'a> {
    use ansi_to_tui::IntoText;
    Box::new(
      self
        .lines
        .iter()
        .rev()
        .map(|(line_id, line, prerender)| BufferItem {
          content: BufferItemContent::SimpleText(line.clone().into_text().unwrap_or_else(|e| {
            tracing::error!("Could not convert line from ANSI codes to ratatui: {}", e);
            Text::raw(line)
          })),
          prerender,
          unique_id: Some(*line_id),
        }),
    )
  }

  fn unread_notification_counts(&self) -> matrix_sdk::sync::UnreadNotificationsCount {
    Default::default()
  }

  fn fully_read(&self) -> FullyReadStatus {
    // TODO
    FullyReadStatus::All
  }
}