extern crate clap;

use self::clap::{App, Arg};
use clap::crate_version;
use regex::Regex;
use std::process::Command;
use std::time::{SystemTime, UNIX_EPOCH};

trait Executor {
  fn execute(&mut self, args: Vec<String>) -> String;
  fn last_executed(&self) -> Option<Vec<String>>;
}

struct RealShell {
  executed: Option<Vec<String>>,
}

impl RealShell {
  fn new() -> RealShell {
    RealShell { executed: None }
  }
}

impl Executor for RealShell {
  fn execute(&mut self, args: Vec<String>) -> String {
    let execution = Command::new(args[0].as_str())
      .args(&args[1..])
      .output()
      .expect("Couldn't run it");

    self.executed = Some(args);

    let output: String = String::from_utf8_lossy(&execution.stdout).into();

    output.trim_end().to_string()
  }

  fn last_executed(&self) -> Option<Vec<String>> {
    self.executed.clone()
  }
}

const TMP_FILE: &str = "/tmp/thumbs-last";

pub struct Swapper<'a> {
  executor: Box<&'a mut dyn Executor>,
  dir: String,
  command: String,
  upcase_command: String,
  active_pane_id: Option<String>,
  active_pane_height: Option<i32>,
  active_pane_scroll_position: Option<i32>,
  active_pane_in_copy_mode: Option<String>,
  thumbs_pane_id: Option<String>,
  content: Option<String>,
  signal: String,
}

impl<'a> Swapper<'a> {
  fn new(executor: Box<&'a mut dyn Executor>, dir: String, command: String, upcase_command: String) -> Swapper {
    let since_the_epoch = SystemTime::now()
      .duration_since(UNIX_EPOCH)
      .expect("Time went backwards");
    let signal = format!("thumbs-finished-{}", since_the_epoch.as_secs());

    Swapper {
      executor,
      dir,
      command,
      upcase_command,
      active_pane_id: None,
      active_pane_height: None,
      active_pane_scroll_position: None,
      active_pane_in_copy_mode: None,
      thumbs_pane_id: None,
      content: None,
      signal,
    }
  }

  pub fn capture_active_pane(&mut self) {
    let active_command = vec![
      "tmux",
      "list-panes",
      "-F",
      "#{pane_id}:#{?pane_in_mode,1,0}:#{pane_height}:#{scroll_position}:#{?pane_active,active,nope}",
    ];

    let output = self
      .executor
      .execute(active_command.iter().map(|arg| arg.to_string()).collect());

    let lines: Vec<&str> = output.split('\n').collect();
    let chunks: Vec<Vec<&str>> = lines.into_iter().map(|line| line.split(':').collect()).collect();

    let active_pane = chunks
      .iter()
      .find(|&chunks| *chunks.get(4).unwrap() == "active")
      .expect("Unable to find active pane");

    let pane_id = active_pane.get(0).unwrap();
    let pane_in_copy_mode = active_pane.get(1).unwrap().to_string();

    self.active_pane_id = Some(pane_id.to_string());
    self.active_pane_in_copy_mode = Some(pane_in_copy_mode);

    if self.active_pane_in_copy_mode.clone().unwrap() == "1" {
      let pane_height = active_pane
        .get(2)
        .unwrap()
        .parse()
        .expect("Unable to retrieve pane height");
      let pane_scroll_position = active_pane
        .get(3)
        .unwrap()
        .parse()
        .expect("Unable to retrieve pane scroll");

      self.active_pane_height = Some(pane_height);
      self.active_pane_scroll_position = Some(pane_scroll_position);
    }
  }

  pub fn execute_thumbs(&mut self) {
    let options_command = vec!["tmux", "show", "-g"];
    let params: Vec<String> = options_command.iter().map(|arg| arg.to_string()).collect();
    let options = self.executor.execute(params);
    let lines: Vec<&str> = options.split('\n').collect();

    let pattern = Regex::new(r#"@thumbs-([\w\-0-9]+) "(.*)""#).unwrap();

    let args = lines
      .iter()
      .flat_map(|line| {
        if let Some(captures) = pattern.captures(line) {
          let name = captures.get(1).unwrap().as_str();
          let value = captures.get(2).unwrap().as_str();

          let boolean_params = vec!["reverse", "unique", "contrast"];

          if boolean_params.iter().any(|&x| x == name) {
            return vec![format!("--{}", name)];
          }

          let string_params = vec![
            "position",
            "fg-color",
            "bg-color",
            "hint-bg-color",
            "hint-fg-color",
            "select-fg-color",
            "select-bg-color",
          ];

          if string_params.iter().any(|&x| x == name) {
            return vec![format!("--{}", name), format!("'{}'", value)];
          }

          if name.starts_with("regexp") {
            return vec!["--regexp".to_string(), format!("'{}'", value)];
          }

          vec![]
        } else {
          vec![]
        }
      })
      .collect::<Vec<String>>();

    let active_pane_id = self.active_pane_id.as_mut().unwrap().clone();

    let scroll_params = if self.active_pane_in_copy_mode.is_some() {
      if let (Some(pane_height), Some(scroll_position)) =
        (self.active_pane_scroll_position, self.active_pane_scroll_position)
      {
        format!(" -S {} -E {}", -scroll_position, pane_height - scroll_position - 1)
      } else {
        "".to_string()
      }
    } else {
      "".to_string()
    };

    // NOTE: For debugging add echo $PWD && sleep 5 after tee
    let pane_command = format!(
        "tmux capture-pane -t {} -p{} | {}/target/release/thumbs -f '%U:%H' -t {} {}; tmux swap-pane -t {}; tmux wait-for -S {}",
        active_pane_id,
        scroll_params,
        self.dir,
        TMP_FILE,
        args.join(" "),
        active_pane_id,
        self.signal
    );

    let thumbs_command = vec![
      "tmux",
      "new-window",
      "-P",
      "-d",
      "-n",
      "[thumbs]",
      pane_command.as_str(),
    ];

    let params: Vec<String> = thumbs_command.iter().map(|arg| arg.to_string()).collect();

    self.thumbs_pane_id = Some(self.executor.execute(params));
  }

  pub fn swap_panes(&mut self) {
    let active_pane_id = self.active_pane_id.as_mut().unwrap().clone();
    let thumbs_pane_id = self.thumbs_pane_id.as_mut().unwrap().clone();

    let swap_command = vec![
      "tmux",
      "swap-pane",
      "-d",
      "-s",
      active_pane_id.as_str(),
      "-t",
      thumbs_pane_id.as_str(),
    ];
    let params = swap_command.iter().map(|arg| arg.to_string()).collect();

    self.executor.execute(params);
  }

  pub fn wait_thumbs(&mut self) {
    let wait_command = vec!["tmux", "wait-for", self.signal.as_str()];
    let params = wait_command.iter().map(|arg| arg.to_string()).collect();

    self.executor.execute(params);
  }

  pub fn retrieve_content(&mut self) {
    let retrieve_command = vec!["cat", TMP_FILE];
    let params = retrieve_command.iter().map(|arg| arg.to_string()).collect();

    self.content = Some(self.executor.execute(params));
  }

  pub fn destroy_content(&mut self) {
    let retrieve_command = vec!["rm", TMP_FILE];
    let params = retrieve_command.iter().map(|arg| arg.to_string()).collect();

    self.executor.execute(params);
  }

  pub fn execute_command(&mut self) {
    let content = self.content.clone().unwrap();
    let mut splitter = content.splitn(2, ':');

    if let Some(upcase) = splitter.next() {
      if let Some(text) = splitter.next() {
        let execute_command = if upcase.trim_end() == "true" {
          self.upcase_command.clone()
        } else {
          self.command.clone()
        };

        let final_command = str::replace(execute_command.as_str(), "{}", text.trim_end());
        let retrieve_command = vec!["bash", "-c", final_command.as_str()];
        let params = retrieve_command.iter().map(|arg| arg.to_string()).collect();

        self.executor.execute(params);
      }
    }
  }
}

#[cfg(test)]
mod tests {
  use super::*;

  struct TestShell {
    outputs: Vec<String>,
    executed: Option<Vec<String>>,
  }

  impl TestShell {
    fn new(outputs: Vec<String>) -> TestShell {
      TestShell {
        executed: None,
        outputs,
      }
    }
  }

  impl Executor for TestShell {
    fn execute(&mut self, args: Vec<String>) -> String {
      self.executed = Some(args);
      self.outputs.pop().unwrap()
    }

    fn last_executed(&self) -> Option<Vec<String>> {
      self.executed.clone()
    }
  }

  #[test]
  fn retrieve_active_pane() {
    let last_command_outputs = vec!["%97:100:24:1:active\n%106:100:24:1:nope\n%107:100:24:1:nope\n".to_string()];
    let mut executor = TestShell::new(last_command_outputs);
    let mut swapper = Swapper::new(Box::new(&mut executor), "".to_string(), "".to_string(), "".to_string());

    swapper.capture_active_pane();

    assert_eq!(swapper.active_pane_id.unwrap(), "%97");
  }

  #[test]
  fn swap_panes() {
    let last_command_outputs = vec![
      "".to_string(),
      "%100".to_string(),
      "".to_string(),
      "%106:100:24:1:nope\n%98:100:24:1:active\n%107:100:24:1:nope\n".to_string(),
    ];
    let mut executor = TestShell::new(last_command_outputs);
    let mut swapper = Swapper::new(Box::new(&mut executor), "".to_string(), "".to_string(), "".to_string());

    swapper.capture_active_pane();
    swapper.execute_thumbs();
    swapper.swap_panes();

    let expectation = vec!["tmux", "swap-pane", "-d", "-s", "%98", "-t", "%100"];

    assert_eq!(executor.last_executed().unwrap(), expectation);
  }
}

fn app_args<'a>() -> clap::ArgMatches<'a> {
  App::new("tmux-thumbs")
    .version(crate_version!())
    .about("A lightning fast version of tmux-fingers, copy/pasting tmux like vimium/vimperator")
    .arg(
      Arg::with_name("dir")
        .help("Directory where to execute thumbs")
        .long("dir")
        .default_value(""),
    )
    .arg(
      Arg::with_name("command")
        .help("Pick command")
        .long("command")
        .default_value("tmux set-buffer {}"),
    )
    .arg(
      Arg::with_name("upcase_command")
        .help("Upcase command")
        .long("upcase-command")
        .default_value("tmux set-buffer {} && tmux paste-buffer"),
    )
    .get_matches()
}

fn main() -> std::io::Result<()> {
  let args = app_args();
  let dir = args.value_of("dir").unwrap();
  let command = args.value_of("command").unwrap();
  let upcase_command = args.value_of("upcase_command").unwrap();

  if dir.is_empty() {
    panic!("Invalid tmux-thumbs execution. Are you trying to execute tmux-thumbs directly?")
  }

  let mut executor = RealShell::new();
  let mut swapper = Swapper::new(
    Box::new(&mut executor),
    dir.to_string(),
    command.to_string(),
    upcase_command.to_string(),
  );

  swapper.capture_active_pane();
  swapper.execute_thumbs();
  swapper.swap_panes();
  swapper.wait_thumbs();
  swapper.retrieve_content();
  swapper.destroy_content();
  swapper.execute_command();
  Ok(())
}