rom-cli 0.2.1

//! CLI interface for ROM
use std::{
  io,
  path::PathBuf,
  process::{Command, Stdio},
};

use clap::Parser;
use cognos::ProgressState;
use tracing_subscriber::EnvFilter;

#[derive(Debug, Parser)]
#[command(name = "rom", version, about = "ROM - A Nix build output monitor")]
pub struct Cli {
  #[command(subcommand)]
  pub command: Option<Commands>,

  /// Parse JSON output from nix --log-format=internal-json
  #[arg(long, global = true)]
  pub json: bool,

  /// Minimal output
  #[arg(long, global = true)]
  pub silent: bool,

  /// Output format: tree, plain, dashboard
  #[arg(long, global = true, default_value = "tree")]
  pub format: String,

  /// Legend display style: compact, table, verbose
  #[arg(long, global = true, default_value = "table")]
  pub legend: String,

  /// Summary display style: concise, table, full
  #[arg(long, global = true, default_value = "concise")]
  pub summary: String,

  /// Log prefix style: short, full, none
  #[arg(long, global = true, default_value = "short")]
  pub log_prefix: String,

  /// Maximum number of log lines to display
  #[arg(long, global = true)]
  pub log_lines: Option<usize>,

  /// Nix-family evaluator to use. Auto-detected by default
  #[arg(long, global = true)]
  pub platform: Option<String>,

  /// Increase verbosity; controls nix log level and rom diagnostic output.
  /// Repeatable: -v (info), -vv (debug), -vvv (trace)
  #[arg(short = 'v', action = clap::ArgAction::Count, global = true)]
  pub verbose: u8,
}

#[derive(Debug, clap::Subcommand)]
pub enum Commands {
  /// Run nix build with monitoring
  Build {
    /// Packages or flake expressions to build
    packages: Vec<String>,

    /// Extra flags to pass directly to nix
    #[arg(last = true)]
    nix_flags: Vec<String>,
  },

  /// Run nix shell with monitoring
  Shell {
    /// Packages or flake expressions
    packages: Vec<String>,

    /// Extra flags to pass directly to nix
    #[arg(last = true)]
    nix_flags: Vec<String>,
  },

  /// Run nix develop with monitoring
  Develop {
    /// Packages or flake expressions
    packages: Vec<String>,

    /// Extra flags to pass directly to nix
    #[arg(last = true)]
    nix_flags: Vec<String>,
  },
}

struct WrapperConfig {
  platform:         cognos::Platform,
  silent:           bool,
  verbose:          u8,
  format:           rom_core::types::DisplayFormat,
  legend_style:     rom_core::types::LegendStyle,
  summary_style:    rom_core::types::SummaryStyle,
  log_prefix_style: rom_core::types::LogPrefixStyle,
  log_lines:        Option<usize>,
}

/// Run the CLI application
pub fn run() -> eyre::Result<()> {
  let cli = Cli::parse();

  // Initialize tracing based on verbosity level; RUST_LOG overrides
  let default_filter = match cli.verbose {
    0 => "rom=warn",
    1 => "rom=info",
    2 => "rom=debug",
    _ => "rom=trace",
  };
  tracing_subscriber::fmt()
    .with_env_filter(
      EnvFilter::try_from_default_env()
        .unwrap_or_else(|_| EnvFilter::new(default_filter)),
    )
    .with_target(false)
    .with_writer(std::io::stderr)
    .init();

  // Pre-parse typed display values before any moves of cli
  let format = rom_core::types::DisplayFormat::from_str(&cli.format);
  let legend_style = rom_core::types::LegendStyle::from_str(&cli.legend);
  let summary_style = rom_core::types::SummaryStyle::from_str(&cli.summary);
  let log_prefix_style =
    rom_core::types::LogPrefixStyle::from_str(&cli.log_prefix);
  let log_lines = cli.log_lines;
  let silent = cli.silent;
  let verbose = cli.verbose;
  let json = cli.json;
  let platform = cli
    .platform
    .as_deref()
    .and_then(|platform| platform.parse().ok())
    .unwrap_or_else(cognos::Platform::detect);

  // Check if we're being called as a symlink (rom-build, rom-shell)
  let program_name = std::env::args()
    .next()
    .and_then(|path| {
      PathBuf::from(&path)
        .file_name()
        .and_then(|n| n.to_str())
        .map(std::string::ToString::to_string)
    })
    .unwrap_or_else(|| "rom".to_string());

  let make_config = |input_mode: rom_core::types::InputMode| {
    rom_core::types::Config {
      piping: false,
      silent,
      input_mode,
      show_timers: true,
      width: None,
      format,
      legend_style,
      summary_style,
      log_prefix_style,
      log_line_limit: log_lines,
    }
  };

  let cfg = WrapperConfig {
    platform,
    silent,
    verbose,
    format,
    legend_style,
    summary_style,
    log_prefix_style,
    log_lines,
  };

  match (&program_name[..], cli.command) {
    // rom-build symlink
    ("rom-build", _) => {
      let args: Vec<String> = std::env::args().skip(1).collect();
      let (packages, nix_flags) = parse_args_with_separator(&args);
      run_build_wrapper(packages, nix_flags, &cfg)?;
      Ok(())
    },

    // rom-shell symlink
    ("rom-shell", _) => {
      let args: Vec<String> = std::env::args().skip(1).collect();
      let (packages, nix_flags) = parse_args_with_separator(&args);
      run_shell_wrapper(packages, nix_flags, &cfg)?;
      Ok(())
    },

    // rom build command
    (
      _,
      Some(Commands::Build {
        packages,
        nix_flags,
      }),
    ) => {
      if packages.is_empty() && json {
        let stdin = io::stdin();
        let stdout = io::stdout();
        return Ok(rom_core::monitor_stream(
          make_config(rom_core::types::InputMode::Json),
          stdin.lock(),
          stdout.lock(),
        )?);
      }
      if packages.is_empty() {
        eyre::bail!(
          "No package or flake specified for build\nUsage: rom build \
           <package> [-- <flags>]\nExample: rom build nixpkgs#hello -- \
           --rebuild"
        );
      }
      run_build_wrapper(packages, nix_flags, &cfg)?;
      Ok(())
    },

    // rom shell command
    (
      _,
      Some(Commands::Shell {
        packages,
        nix_flags,
      }),
    ) => {
      if packages.is_empty() && json {
        let stdin = io::stdin();
        let stdout = io::stdout();
        return Ok(rom_core::monitor_stream(
          make_config(rom_core::types::InputMode::Json),
          stdin.lock(),
          stdout.lock(),
        )?);
      }
      if packages.is_empty() {
        eyre::bail!(
          "No package or flake specified for shell\nUsage: rom shell \
           <package> [-- <flags>]\nExample: rom shell nixpkgs#python3 -- \
           --pure"
        );
      }
      run_shell_wrapper(packages, nix_flags, &cfg)?;
      Ok(())
    },

    // rom develop command
    (
      _,
      Some(Commands::Develop {
        packages,
        nix_flags,
      }),
    ) => {
      if packages.is_empty() && json {
        let stdin = io::stdin();
        let stdout = io::stdout();
        return Ok(rom_core::monitor_stream(
          make_config(rom_core::types::InputMode::Json),
          stdin.lock(),
          stdout.lock(),
        )?);
      }
      if packages.is_empty() {
        eyre::bail!(
          "No package or flake specified for develop\nUsage: rom develop \
           <package> [-- <flags>]\nExample: rom develop nixpkgs#hello -- \
           --impure"
        );
      }
      run_develop_wrapper(packages, nix_flags, &cfg)?;
      Ok(())
    },

    // Direct piping mode, read from stdin
    (_, None) => {
      let input_mode = if json {
        rom_core::types::InputMode::Json
      } else {
        rom_core::types::InputMode::Human
      };
      let stdin = io::stdin();
      let stdout = io::stdout();
      Ok(rom_core::monitor_stream(
        make_config(input_mode),
        stdin.lock(),
        stdout.lock(),
      )?)
    },
  }
}

/// Parse arguments, separating those before and after `--`
/// Returns (`args_before_separator`, `args_after_separator`)
///
/// Everything before `--` is for the package name and rom arguments.
/// Everything after `--` goes directly to nix.
#[must_use]
pub fn parse_args_with_separator(
  args: &[String],
) -> (Vec<String>, Vec<String>) {
  if let Some(pos) = args.iter().position(|arg| arg == "--") {
    // Arguments before -- are package/rom args
    let before = args[..pos].to_vec();

    // Arguments after -- go to nix
    let after = args[pos + 1..].to_vec();
    (before, after)
  } else {
    // No separator found - all args are package/rom args for backward
    // compatibility
    (args.to_vec(), Vec::new())
  }
}

/// Returns the nix verbosity flag for the given level.
/// Always produces at least `-v` so build events are emitted via
/// `--log-format internal-json`.
fn nix_verbosity_flag(verbose: u8) -> String {
  format!("-{}", "v".repeat(verbose.max(1) as usize))
}

fn run_build_wrapper(
  packages: Vec<String>,
  nix_flags: Vec<String>,
  cfg: &WrapperConfig,
) -> eyre::Result<()> {
  if packages.is_empty() {
    eyre::bail!(
      "No package or flake specified for build\nUsage: rom build <package> \
       [-- <flags>]\nExample: rom build nixpkgs#hello -- --rebuild"
    );
  }

  let mut cmd_args = vec![
    "build".to_string(),
    nix_verbosity_flag(cfg.verbose),
    "--log-format".to_string(),
    "internal-json".to_string(),
  ];
  cmd_args.extend(packages);
  cmd_args.extend(nix_flags);

  let exit_code = run_monitored_command(cfg.platform.binary(), cmd_args, cfg)?;
  if exit_code != 0 {
    std::process::exit(exit_code);
  }
  Ok(())
}

fn run_shell_wrapper(
  packages: Vec<String>,
  nix_flags: Vec<String>,
  cfg: &WrapperConfig,
) -> eyre::Result<()> {
  if packages.is_empty() {
    eyre::bail!(
      "No package or flake specified for shell\nUsage: rom shell <package> \
       [-- <flags>]\nExample: rom shell nixpkgs#python3 -- --pure"
    );
  }

  // First pass: monitor the build phase with --command exit
  let mut monitor_args = vec![
    "shell".to_string(),
    nix_verbosity_flag(cfg.verbose),
    "--log-format".to_string(),
    "internal-json".to_string(),
  ];
  let shell_args: Vec<String> =
    packages.iter().chain(nix_flags.iter()).cloned().collect();
  monitor_args.extend(replace_command_with_exit(&shell_args));

  let exit_code =
    run_monitored_command(cfg.platform.binary(), monitor_args, cfg)?;

  if exit_code != 0 {
    std::process::exit(exit_code);
  }

  // Second pass: enter the actual shell
  if !cfg.silent {
    let mut shell_args = vec!["shell".to_string()];
    shell_args.extend(packages);
    shell_args.extend(nix_flags);

    let status = Command::new(cfg.platform.binary())
      .args(&shell_args)
      .status()
      .map_err(rom_core::error::RomError::Io)?;

    std::process::exit(status.code().unwrap_or(1));
  }

  Ok(())
}

fn run_develop_wrapper(
  packages: Vec<String>,
  nix_flags: Vec<String>,
  cfg: &WrapperConfig,
) -> eyre::Result<()> {
  // First pass: monitor with --command true
  let mut monitor_args = vec![
    "develop".to_string(),
    nix_verbosity_flag(cfg.verbose),
    "--log-format".to_string(),
    "internal-json".to_string(),
    "--command".to_string(),
    "true".to_string(),
  ];
  monitor_args.extend(packages.clone());
  monitor_args.extend(nix_flags.clone());

  let exit_code =
    run_monitored_command(cfg.platform.binary(), monitor_args, cfg)?;

  if exit_code != 0 {
    std::process::exit(exit_code);
  }

  // Second pass: enter the actual dev shell
  if !cfg.silent {
    let mut develop_args = vec!["develop".to_string()];
    develop_args.extend(packages);
    develop_args.extend(nix_flags);

    let status = Command::new(cfg.platform.binary())
      .args(&develop_args)
      .status()
      .map_err(rom_core::error::RomError::Io)?;

    std::process::exit(status.code().unwrap_or(1));
  }

  Ok(())
}

fn run_monitored_command(
  command: &str,
  args: Vec<String>,
  cfg: &WrapperConfig,
) -> eyre::Result<i32> {
  let silent = cfg.silent;
  let format = cfg.format;
  let legend_style = cfg.legend_style;
  let summary_style = cfg.summary_style;
  let log_prefix_style = cfg.log_prefix_style;
  let log_line_limit = cfg.log_lines;
  use std::{
    io::{BufRead, BufReader},
    sync::{Arc, Mutex},
    thread,
    time::Duration,
  };

  let mut child = Command::new(command)
    .args(&args)
    .stdout(Stdio::piped())
    .stderr(Stdio::piped())
    .spawn()
    .map_err(rom_core::error::RomError::Io)?;

  let stderr = child.stderr.take().expect("Failed to capture stderr");
  let stdout = child.stdout.take().expect("Failed to capture stdout");

  // Create shared state
  let state = Arc::new(Mutex::new(rom_core::state::State::new()));
  let state_clone = state.clone();
  let render_state = state;

  // Track whether we're done processing
  let processing_done = Arc::new(Mutex::new(false));
  let processing_done_clone = processing_done.clone();

  // Track start time for initial timer
  let start_time = Arc::new(Mutex::new(rom_core::state::current_time()));
  let start_time_clone = start_time;

  // Buffer for build logs - collected and passed to Display for coordinated
  // rendering
  let log_buffer =
    Arc::new(Mutex::new(std::collections::VecDeque::<String>::new()));
  let log_buffer_clone = log_buffer.clone();
  let log_buffer_render = log_buffer;

  // Spawn thread to read and parse stderr (where nix outputs logs)
  let stderr_thread = thread::spawn(move || {
    use tracing::debug;
    let reader = BufReader::new(stderr);
    let mut json_count = 0;
    let mut non_json_count = 0;

    for line in reader.lines().map_while(Result::ok) {
      // Try to parse as JSON message
      if let Some(json_line) = line.strip_prefix("@nix ") {
        json_count += 1;
        if let Ok(action) = serde_json::from_str::<cognos::Actions>(json_line) {
          debug!("Parsed JSON message #{}: {:?}", json_count, action);

          // Process the action first to update state
          let mut state = state_clone.lock().unwrap();
          let derivation_count_before = state.derivation_infos.len();
          rom_core::update::process_message(&mut state, action.clone());
          rom_core::update::maintain_state(
            &mut state,
            rom_core::state::current_time(),
          );
          let derivation_count_after = state.derivation_infos.len();

          // Now handle build log messages after state is updated
          // Buffer them for coordinated rendering with the display
          match &action {
            cognos::Actions::Message { msg, raw_msg, .. } => {
              // Prefer raw_msg (Lix): message without ANSI escapes.
              let display = raw_msg.as_deref().unwrap_or(msg.as_str());
              let mut logs = log_buffer_clone.lock().unwrap();
              logs.push_back(display.to_string());
              if let Some(limit) = log_line_limit {
                while logs.len() > limit {
                  logs.pop_front();
                }
              }
            },
            cognos::Actions::Result {
              fields,
              result_type,
              id,
            } => {
              // BuildLogLine (101) carries a single log line from the builder
              if matches!(result_type, cognos::ResultType::BuildLogLine)
                && !fields.is_empty()
                && let Some(log_text) = fields[0].as_str()
              {
                let use_color = !silent;
                let prefix = state
                  .get_activity_prefix(*id, &log_prefix_style, use_color)
                  .unwrap_or_default();
                let prefixed_log = format!("{prefix}{log_text}");
                let mut logs = log_buffer_clone.lock().unwrap();
                logs.push_back(prefixed_log);
                if let Some(limit) = log_line_limit {
                  while logs.len() > limit {
                    logs.pop_front();
                  }
                }
              }
            },
            _ => {},
          }

          if derivation_count_after != derivation_count_before {
            debug!(
              "Derivation count changed: {} -> {}",
              derivation_count_before, derivation_count_after
            );
          }
        } else {
          debug!("Failed to parse JSON: {}", json_line);
        }
      } else {
        // Non-JSON lines, buffer them
        non_json_count += 1;
        let mut logs = log_buffer_clone.lock().unwrap();
        logs.push_back(line.clone());
        // Keep only recent logs based on limit
        if let Some(limit) = log_line_limit {
          while logs.len() > limit {
            logs.pop_front();
          }
        }
      }
    }
    debug!(
      "Stderr thread finished: {} JSON messages, {} non-JSON lines",
      json_count, non_json_count
    );
    *processing_done_clone.lock().unwrap() = true;
  });

  // Read stdout (final nix output)
  let stdout_lines = Arc::new(Mutex::new(Vec::new()));
  let stdout_lines_clone = stdout_lines.clone();

  let stdout_thread = thread::spawn(move || {
    let reader = BufReader::new(stdout);
    for line in reader.lines().map_while(Result::ok) {
      stdout_lines_clone.lock().unwrap().push(line);
    }
  });

  // Render loop, this is what displays the build graph
  let render_thread = thread::spawn(move || {
    use rom_core::display::{Display, DisplayConfig};

    let display_config = DisplayConfig {
      show_timers: true,
      max_tree_depth: 10,
      max_visible_lines: 100,
      use_color: true,
      format,
      legend_style,
      summary_style,
      icons: rom_core::icons::detect(),
    };

    let mut display = Display::new(io::stderr(), display_config).unwrap();
    let mut last_timer_display: Option<String> = None;

    // Render loop
    loop {
      thread::sleep(Duration::from_millis(100));
      let done = *processing_done.lock().unwrap();

      let state = render_state.lock().unwrap();
      let has_activity = !state.derivation_infos.is_empty()
        || !state.full_summary.running_builds.is_empty()
        || !state.full_summary.planned_builds.is_empty();

      {
        // Get buffered logs for coordinated rendering (suppressed when
        // --silent)
        let logs: Vec<String> = if silent {
          vec![]
        } else {
          log_buffer_render.lock().unwrap().iter().cloned().collect()
        };

        if has_activity || state.progress_state != ProgressState::JustStarted {
          // Clear any previous timer display
          if last_timer_display.is_some() {
            last_timer_display = None;
          }
          let _ = display.render(&state, &logs);
        } else {
          // Show initial timer while waiting for activity
          let start = *start_time_clone.lock().unwrap();
          let elapsed = rom_core::state::current_time() - start;
          let timer_text =
            format!("⏱ {}", rom_core::display::format_duration(elapsed));

          // Only update if changed (to avoid flicker)
          if last_timer_display.as_ref() != Some(&timer_text) {
            let _ = display.render(&state, &logs);
            last_timer_display = Some(timer_text);
          }
        }
      }

      if done {
        break;
      }
    }

    // Final render
    thread::sleep(Duration::from_millis(50));
    {
      let mut state = render_state.lock().unwrap();
      rom_core::update::finish_state(&mut state);
      let _ = display.render_final(&state);
    }
  });

  // Wait for process to complete
  let status = child.wait().map_err(rom_core::error::RomError::Io)?;

  // Wait for threads to finish
  let _ = stderr_thread.join();
  let _ = stdout_thread.join();
  let _ = render_thread.join();

  // Print captured stdout (nix's final output)
  let stdout_lines = stdout_lines.lock().unwrap();
  for line in stdout_lines.iter() {
    use std::io::Write;
    let _ = writeln!(std::io::stdout(), "{line}");
  }

  Ok(status.code().unwrap_or(1))
}

/// Replace --command/-c arguments with "sh -c exit" for monitoring pass
pub fn replace_command_with_exit(args: &[String]) -> Vec<String> {
  let mut result = Vec::new();
  let mut skip_next = false;

  for arg in args {
    if skip_next {
      skip_next = false;
      continue;
    }

    if arg == "--command" || arg == "-c" {
      // Skip this and the next argument
      skip_next = true;
      continue;
    }

    result.push(arg.clone());
  }

  // Add our exit command
  result.push("--command".to_string());
  result.push("sh".to_string());
  result.push("-c".to_string());
  result.push("exit".to_string());

  result
}