dmc-core 0.2.0

use std::path::PathBuf;
use std::sync::mpsc::channel;
use std::time::{Duration, Instant};

use dmc_diagnostic::Code;
use duck_diagnostic::{DiagnosticEngine, print_all_smart};
use notify_debouncer_mini::{new_debouncer, notify::RecursiveMode};

use crate::{Engine, engine::config::EngineConfig};

/// Initial build, then watch every collection's `base_dir` (plus the
/// config file) and rebuild on change.
#[derive(clap::Args)]
pub struct DevCmd {
  #[arg(long, default_value = "dmc.toml")]
  pub config: PathBuf,
  #[arg(short, long)]
  pub strict: bool,
  #[arg(long)]
  pub clean: bool,
  /// Debounce window for filesystem events (ms).
  #[arg(long, default_value_t = 100)]
  pub debounce: u64,
}

impl DevCmd {
  pub fn run(self) -> std::io::Result<()> {
    let mut cfg = EngineConfig::load(&self.config)?;
    if self.strict {
      cfg.strict = true;
    }
    if self.clean {
      cfg.clean = true;
    }

    rebuild(&cfg, &self.config, "initial");

    let (tx, rx) = channel();
    let mut deb =
      new_debouncer(Duration::from_millis(self.debounce), tx).map_err(|e| std::io::Error::other(e.to_string()))?;

    let mut roots: Vec<PathBuf> = cfg.collections.iter().map(|c| c.base_dir.clone()).collect();
    roots.push(self.config.clone());
    for r in &roots {
      if r.exists() {
        deb.watcher().watch(r, RecursiveMode::Recursive).map_err(|e| std::io::Error::other(e.to_string()))?;
      }
    }

    println!("watching {} root(s) - Ctrl-C to stop", roots.len());

    while let Ok(events) = rx.recv() {
      let Ok(events) = events else { continue };
      let touched: Vec<PathBuf> = events.iter().map(|e| e.path.clone()).collect();
      let cfg_canon = self.config.canonicalize().ok();
      let config_changed = touched.iter().any(|p| p.canonicalize().ok() == cfg_canon);

      if config_changed {
        match EngineConfig::load(&self.config) {
          Ok(mut next) => {
            if self.strict {
              next.strict = true;
            }
            if self.clean {
              next.clean = true;
            }
            cfg = next;
          },
          Err(e) => {
            eprintln!("config reload failed: {e}");
            continue;
          },
        }
      }

      rebuild(&cfg, &self.config, if config_changed { "config" } else { "files" });
    }

    Ok(())
  }
}

fn rebuild(cfg: &EngineConfig, config_path: &std::path::Path, trigger: &str) {
  let mut diag_engine = DiagnosticEngine::<Code>::new();
  let started = Instant::now();
  let result = Engine::run(cfg, Some(config_path), &mut diag_engine);
  let elapsed = started.elapsed();
  print_all_smart(&diag_engine, None);
  match result {
    Ok(()) => println!("rebuilt ({trigger}) in {:?}", elapsed),
    Err(e) => eprintln!("build error ({trigger}): {e}"),
  }
}