//! What share of bundles have a NARROW settle window -- and of WHICH bundles?
//!
//! `screen render --settle`'s help says "a narrow one means the bundle never
//! settles (42 % of them, mostly `loop*` fragments)". The 42 % is correct and is
//! stated precisely in ui-settle-time.md: 731 of **1 758 composable bundles
//! carrying two or more keyframe times**. But inside `screen render`, "them"
//! reads as the bundles you would render -- the SCREEN BUILDS -- which is a
//! different and much smaller population. This computes both.
//!
//!     cargo run -p sylpheed-formats --example settle_narrow_rate
use std::path::PathBuf;
use sylpheed_formats::{pak::PakArchive, ui_layout};

fn main() {
    let root = PathBuf::from(std::env::var("SYLPHEED_DISC").expect("SYLPHEED_DISC"));
    let mut paks: Vec<PathBuf> = std::fs::read_dir(root.join("dat"))
        .expect("dat/")
        .filter_map(|e| e.ok().map(|e| e.path()))
        .filter(|p| p.extension().is_some_and(|x| x == "pak"))
        .collect();
    paks.sort();
    // (with >=2 keyframe times, narrow) for each population
    let (mut b2, mut bn) = (0usize, 0usize); // screen builds  (is_build)
    let (mut c2, mut cn) = (0usize, 0usize); // composable      (is_composable)
    for pak in &paks {
        let Ok(ar) = PakArchive::open(pak) else {
            continue;
        };
        for e in ar.entries() {
            let Ok(by) = ar.read(e) else { continue };
            let is_b = ui_layout::is_build(&by);
            let is_c = ui_layout::is_composable(&by);
            if !is_b && !is_c {
                continue;
            }
            let Some(b) = ui_layout::parse_build(&by) else {
                continue;
            };
            let mut ts: Vec<u32> = b
                .elements
                .iter()
                .flat_map(|el| el.keyframes.iter().filter_map(|k| k.time))
                .collect();
            ts.sort_unstable();
            ts.dedup();
            if ts.len() < 2 {
                continue;
            }
            let narrow = match b.settle_window() {
                Some((lo, hi)) => hi - lo < 10,
                None => true,
            };
            if is_b {
                b2 += 1;
                if narrow {
                    bn += 1
                }
            }
            if is_c {
                c2 += 1;
                if narrow {
                    cn += 1
                }
            }
        }
    }
    println!("population                                        n     narrow (<10 u)   share");
    println!("SCREEN BUILDS (is_build, what `screen render` renders by default)");
    println!(
        "                                              {b2:5}   {bn:9}      {:.0} %",
        100.0 * bn as f64 / b2.max(1) as f64
    );
    println!("COMPOSABLE bundles (is_composable, what --all admits)");
    println!(
        "                                              {c2:5}   {cn:9}      {:.0} %",
        100.0 * cn as f64 / c2.max(1) as f64
    );
    println!("\nui-settle-time.md quotes 731 / 1758 = 42 % over composable bundles.");
    println!("--- END ---");
}