//! Conformance corpus for exact splats (`live-conformance/splat/`, extensions/splat-exact.md §11).
//!
//!   wai_splat_exact_vectors gen    <corpus-dir>   write vectors.json and assets/ from fixed inputs
//!   wai_splat_exact_vectors verify <corpus-dir>   every file regenerates byte for byte, no other
//!                                                 file but README.md is there, and every case
//!                                                 gets the outcome it states
//!
//! The generator and this verifier are one implementation. The corpus's second
//! implementation is `live-conformance/splat_exact_verify.py`, written from the extension's
//! text and sharing no code with this binary.

use std::collections::BTreeMap;
use std::path::Path;
use wai::splat_exact::corpus;

fn main() {
    let a: Vec<String> = std::env::args().collect();
    match (a.get(1).map(String::as_str), a.get(2)) {
        (Some("gen"), Some(d)) => {
            for (name, body) in corpus::generate() {
                let p = Path::new(d).join(&name);
                if let Some(parent) = p.parent()
                    && let Err(e) = std::fs::create_dir_all(parent)
                {
                    eprintln!("create {}: {e}", parent.display());
                    std::process::exit(1);
                }
                if let Err(e) = std::fs::write(&p, body) {
                    eprintln!("write {}: {e}", p.display());
                    std::process::exit(1);
                }
            }
            println!("wrote {d}");
        }
        (Some("verify"), Some(d)) => std::process::exit(verify(Path::new(d))),
        _ => {
            eprintln!("usage: wai_splat_exact_vectors gen|verify <corpus-dir>");
            std::process::exit(2);
        }
    }
}

/// Every file under `dir`, by its path relative to `dir` with `/` separators.
fn walk(dir: &Path, rel: &str, out: &mut BTreeMap<String, Vec<u8>>) -> std::io::Result<()> {
    for e in std::fs::read_dir(dir)? {
        let e = e?;
        let name = e.file_name().to_string_lossy().into_owned();
        let r = if rel.is_empty() { name.clone() } else { format!("{rel}/{name}") };
        if e.file_type()?.is_dir() {
            walk(&e.path(), &r, out)?;
        } else if r != "README.md" {
            out.insert(r, std::fs::read(e.path())?);
        }
    }
    Ok(())
}

fn verify(dir: &Path) -> i32 {
    let mut files = BTreeMap::new();
    if let Err(e) = walk(dir, "", &mut files) {
        eprintln!("read {}: {e}", dir.display());
        return 1;
    }
    let generated: BTreeMap<String, Vec<u8>> = corpus::generate().into_iter().collect();
    let same = files == generated;
    println!("{} every file regenerates byte for byte from its inputs, and no other file is there", if same { "PASS" } else { "FAIL" });
    if !same {
        for k in files.keys().chain(generated.keys()) {
            if files.get(k) != generated.get(k) {
                println!("  differs: {k}");
            }
        }
    }
    let fails = corpus::verify(&files);
    for f in &fails {
        println!("FAIL {f}");
    }
    println!("{} every case gets the outcome the corpus states", if fails.is_empty() { "PASS" } else { "FAIL" });
    (!same || !fails.is_empty()) as i32
}
