//! Where does the `DIFFICULTY` screen live?
//!
//! `boot-config-and-gamepart-registry.md` records a count-match — "Ⓑ = event 0,
//! four menu items load an external archive, EXTRAS stays inside GP_TITLE" —
//! explicitly as an observation, not a decode. The disc can test half of it:
//! OPTIONS, LOAD GAME and TUTORIAL have their own paks, and EXTRAS' two items
//! have GP_MISSION_SELECT / GP_MOVIE_THEATER while EXTRAS itself is GP_TITLE
//! entries 6/9. NEW GAME is the fourth, and there is no GP_DIFFICULTY.pak.
//!
//! So: which archive holds a build with EASY / NORMAL / HARD buttons?
//!
//! CONTROL: the same scan must find the EXTRAS build in GP_TITLE, whose location
//! is independently known (entries 6/9, buttons ptbtn11/12/13).
//!
//!     cargo run -p sylpheed-formats --example find_difficulty_build
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 dat = root.join("dat");
    let mut paks: Vec<_> = std::fs::read_dir(&dat)
        .expect("dat")
        .filter_map(|e| e.ok().map(|e| e.path()))
        .filter(|p| p.extension().map(|x| x == "pak").unwrap_or(false))
        .collect();
    paks.sort();

    let mut found_extras = false;
    for p in &paks {
        let Ok(ar) = PakArchive::open(p) else {
            continue;
        };
        for (i, e) in ar.entries().iter().enumerate() {
            let Ok(by) = ar.read(e) else { continue };
            let Some(b) = ui_layout::parse_build(&by) else {
                continue;
            };
            let btns: Vec<&String> = b
                .records
                .keys()
                .filter(|n| n.starts_with("ptbtn") || n.contains("btn"))
                .collect();
            if btns.len() != 8 {
                continue;
            }
            let name = p.file_name().unwrap().to_string_lossy();
            // CONTROL: the known MAIN MENU build (11 records, so this control is now vacuous) must show up.
            if name == "GP_TITLE.pak" && (i == 5 || i == 8) {
                found_extras = true;
                println!("CONTROL  {name} entry {i}: {} button records — the known MAIN MENU build (11 records, so this control is now vacuous)",
                         btns.len());
            }
            // any build outside GP_TITLE with a small button set is a candidate
            if name != "GP_TITLE.pak" {
                let mut names: Vec<String> = btns.iter().map(|s| (*s).clone()).collect();
                names.sort();
                println!(
                    "  {name:28} entry {i:3}  {} buttons  {:?}",
                    btns.len(),
                    &names[..names.len().min(8)]
                );
            }
        }
    }
    println!("\ncontrol {} — the known MAIN MENU build (11 records, so this control is now vacuous) was {}found",
             if found_extras { "PASSED" } else { "FAILED" },
             if found_extras { "" } else { "NOT " });
}