//! Keeps the concurrent-read harnesses working: runs `concurrent_read`, the
//! h5py script (threads and processes) and the comparison script end to end
//! on tiny files. h5py reading the files also checks, element by element at
//! spot positions, that both harnesses generate the same data and slabs.
//!
//! The h5py half is skipped when python3 with h5py is unavailable, unless
//! `CLAWHDF5_REQUIRE_INTEROP=1`; `CLAWHDF5_PYTHON` picks the interpreter.

use std::path::{Path, PathBuf};
use std::process::Command;

fn python() -> String {
    std::env::var("CLAWHDF5_PYTHON").unwrap_or_else(|_| "python3".to_string())
}

fn interop_required() -> bool {
    std::env::var("CLAWHDF5_REQUIRE_INTEROP").is_ok_and(|v| v == "1")
}

fn python_available() -> bool {
    Command::new(python())
        .args(["-c", "import h5py, numpy"])
        .output()
        .map(|o| o.status.success())
        .unwrap_or(false)
}

fn scripts() -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR")).join("scripts")
}

fn run(cmd: &mut Command) -> String {
    let out = cmd.output().expect("spawn");
    assert!(
        out.status.success(),
        "{cmd:?} failed\nSTDOUT:\n{}\nSTDERR:\n{}",
        String::from_utf8_lossy(&out.stdout),
        String::from_utf8_lossy(&out.stderr)
    );
    String::from_utf8_lossy(&out.stdout).into_owned()
}

const SMALL: [&str; 8] = [
    "--threads",
    "1,2",
    "--slabs",
    "8",
    "--reps",
    "1",
    "--slab",
    "64",
];

fn results(path: &Path) -> serde_json::Value {
    serde_json::from_str(&std::fs::read_to_string(path).unwrap()).unwrap()
}

#[test]
fn harnesses_run_end_to_end_on_tiny_files() {
    let dir = tempfile::TempDir::new().unwrap();
    let data = dir.path().join("data");
    let claw = dir.path().join("claw.json");

    let bin = env!("CARGO_BIN_EXE_concurrent_read");
    run(Command::new(bin)
        .arg("--dir")
        .arg(&data)
        .args(["--datasets", "3", "--mib", "1"])
        .args(SMALL)
        .arg("--json")
        .arg(&claw));
    // Second run reuses the files (and exercises --cold).
    let out = Command::new(bin)
        .arg("--dir")
        .arg(&data)
        .args(["--datasets", "3", "--mib", "1", "--cold"])
        .args(SMALL)
        .output()
        .unwrap();
    assert!(out.status.success());
    assert!(String::from_utf8_lossy(&out.stderr).contains("reusing"));

    let doc = results(&claw);
    assert_eq!(doc["tool"], "clawhdf5");
    // 2 layouts x 2 modes x 2 thread counts.
    assert_eq!(doc["results"].as_array().unwrap().len(), 8);
    for r in doc["results"].as_array().unwrap() {
        assert!(r["mb_s"].as_f64().unwrap() > 0.0, "{r}");
    }

    if !python_available() {
        assert!(
            !interop_required(),
            "CLAWHDF5_REQUIRE_INTEROP=1 but {} has no h5py",
            python()
        );
        eprintln!("skipping the h5py half: no h5py in {}", python());
        return;
    }
    let mut jsons = vec![claw];
    for executor in ["threads", "processes"] {
        let out = dir.path().join(format!("h5py-{executor}.json"));
        run(Command::new(python())
            .arg(scripts().join("concurrent_read_h5py.py"))
            .arg("--dir")
            .arg(&data)
            .args(["--executor", executor])
            .args(SMALL)
            .arg("--json")
            .arg(&out));
        let doc = results(&out);
        assert_eq!(doc["tool"], format!("h5py-{executor}"));
        assert_eq!(doc["results"].as_array().unwrap().len(), 8);
        jsons.push(out);
    }
    let table = run(Command::new(python())
        .arg(scripts().join("compare_concurrent_read.py"))
        .args(&jsons));
    assert!(table.contains("| deflate | same | 2 |"), "{table}");
    assert!(table.contains("clawhdf5 / h5py-processes"), "{table}");

    // A different workload must not be compared.
    let other = dir.path().join("other.json");
    run(Command::new(python())
        .arg(scripts().join("concurrent_read_h5py.py"))
        .arg("--dir")
        .arg(&data)
        .args([
            "--threads",
            "1",
            "--slabs",
            "4",
            "--reps",
            "1",
            "--slab",
            "64",
        ])
        .arg("--json")
        .arg(&other));
    let out = Command::new(python())
        .arg(scripts().join("compare_concurrent_read.py"))
        .arg(&jsons[0])
        .arg(&other)
        .output()
        .unwrap();
    assert!(!out.status.success());
    assert!(String::from_utf8_lossy(&out.stderr).contains("slabs"));
}