//! Golden tests against the output of the former Python driver
//! (`hpcs6500.py`), generated from real USB captures.

use hpcs6500::format::{csv_header, csv_row, format_quick, format_reading, pcap_report};
use hpcs6500::{Reading, pcap, pyfmt};
use serde_json::Value;
use std::path::{Path, PathBuf};

fn dir(sub: &str) -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR"))
        .join("tests")
        .join(sub)
}

fn fixture(name: &str) -> Reading {
    let meas = std::fs::read(dir("fixtures").join(format!("{name}_meas.bin"))).unwrap();
    let elec = std::fs::read(dir("fixtures").join(format!("{name}_elec.bin"))).ok();
    Reading::parse(&meas, elec.as_deref()).unwrap()
}

fn golden() -> Vec<Value> {
    serde_json::from_str(&std::fs::read_to_string(dir("golden").join("readings.json")).unwrap())
        .unwrap()
}

fn text(name: &str) -> String {
    std::fs::read_to_string(dir("golden").join(name))
        .unwrap()
        .replace("\r\n", "\n")
}

/// Python values in the golden file: floats as {"f": repr}, lists, ints, strings.
fn same(rust: &Value, py: &Value, path: &str) {
    match py {
        Value::Object(o) if o.contains_key("f") => {
            let want = o["f"].as_str().unwrap();
            let got = pyfmt::repr(
                rust.as_f64()
                    .unwrap_or_else(|| panic!("{path}: not a number: {rust}")),
            );
            assert_eq!(got, want, "{path}");
        }
        Value::Array(a) => {
            let r = rust
                .as_array()
                .unwrap_or_else(|| panic!("{path}: not a list"));
            assert_eq!(r.len(), a.len(), "{path}: length");
            for (i, (x, y)) in r.iter().zip(a).enumerate() {
                same(x, y, &format!("{path}[{i}]"));
            }
        }
        other => assert_eq!(rust, other, "{path}"),
    }
}

#[test]
fn parsed_blocks_match_python_exactly() {
    for g in golden() {
        let name = g["name"].as_str().unwrap();
        let r = fixture(name);
        let v = serde_json::to_value(&r).unwrap();
        let keys: Vec<&str> = v.as_object().unwrap().keys().map(|k| k.as_str()).collect();
        let want: Vec<&str> = g["keys"]
            .as_array()
            .unwrap()
            .iter()
            .map(|k| k.as_str().unwrap())
            .collect();
        assert_eq!(keys, want, "{name}: key order");
        for k in want {
            same(&v[k], &g["values"][k], &format!("{name}.{k}"));
        }
        assert_eq!(
            r.electrical.as_ref().unwrap().harmonics.is_some(),
            g["harmonics"].as_bool().unwrap(),
            "{name}"
        );
    }
}

#[test]
fn report_text_matches_python() {
    for g in golden() {
        let name = g["name"].as_str().unwrap();
        let r = fixture(name);
        assert_eq!(
            format_reading(&r, false),
            text(&format!("format_{name}.txt")),
            "{name}"
        );
        assert_eq!(
            format_reading(&r, true),
            text(&format!("format_{name}_spectrum.txt")),
            "{name} spectrum"
        );
        let n: usize = name[1..].parse().unwrap();
        assert_eq!(
            format!("{}\n{}", format_quick(&r, Some(n)), format_quick(&r, None)),
            text(&format!("quick_{name}.txt"))
        );
    }
}

#[test]
fn csv_matches_python() {
    for g in golden() {
        let name = g["name"].as_str().unwrap();
        let want = std::fs::read_to_string(dir("golden").join(format!("csv_{name}.txt"))).unwrap();
        assert_eq!(csv_header() + &csv_row("T", &fixture(name)), want, "{name}");
    }
}

#[test]
fn float_formatting_matches_python() {
    let cases: Vec<Value> =
        serde_json::from_str(&std::fs::read_to_string(dir("golden").join("pyfmt.json")).unwrap())
            .unwrap();
    assert!(cases.len() > 1000);
    for c in &cases {
        let x = f64::from_bits(c["bits"].as_u64().unwrap());
        assert_eq!(pyfmt::repr(x), c["repr"].as_str().unwrap(), "repr {x:e}");
        assert_eq!(pyfmt::g(x, 6), c["g6"].as_str().unwrap(), "g6 {x:e}");
        for (k, p) in [("f2", 2), ("f1", 1), ("f0", 0)] {
            if let Some(w) = c[k].as_str() {
                assert_eq!(pyfmt::fixed(x, p), w, "{k} {x:e}");
            }
        }
        if let Some(w) = c["round1"].as_str() {
            assert_eq!(pyfmt::repr(pyfmt::round(x, 1)), w, "round1 {x:e}");
        }
    }
}

#[test]
fn pcap_round_trip_and_report() {
    // a capture with two readings, written in memory
    let (a, b) = (fixture("r01"), fixture("r02"));
    let block =
        |n: &str, k: &str| std::fs::read(dir("fixtures").join(format!("{n}_{k}.bin"))).unwrap();
    let file = pcap::write(&[
        (pcap::Dir::Tx, vec![0x8C, 0x13]),
        (pcap::Dir::Rx, vec![0x8C, 0x13, 0x0F, 0x40]),
        (pcap::Dir::Rx, block("r01", "meas")),
        (pcap::Dir::Rx, block("r01", "elec")),
        (pcap::Dir::Rx, block("r02", "meas")),
        (pcap::Dir::Rx, block("r02", "elec")),
    ]);
    let msgs = pcap::messages(&file).unwrap();
    assert_eq!(msgs.len(), 6);
    assert_eq!(msgs[0].dir, pcap::Dir::Tx);
    assert_eq!(pcap::readings(&msgs), vec![a, b]);
    let report = pcap_report(&msgs, true, false);
    assert_eq!(report.lines().count(), 2);
    assert!(pcap::messages(&[]).is_err());
    assert!(pcap::messages(&[0u8; 30]).is_err());
}

/// The `--parse` reports of real captures. The captures are not in git
/// (`captures/` is ignored); the test runs where they are.
#[test]
fn parse_reports_of_real_captures() {
    let caps = Path::new(env!("CARGO_MANIFEST_DIR")).join("captures");
    let mut checked = 0;
    for cap in [
        "usb_capture_20260204_123655_hub1",
        "usb_capture_20260204_134301_hub1",
    ] {
        let path = caps.join(format!("{cap}.pcap"));
        if !path.exists() {
            eprintln!("skipped: {} not here", path.display());
            continue;
        }
        let msgs = pcap::read_messages(&path).unwrap();
        assert_eq!(
            pcap_report(&msgs, false, false),
            text(&format!("parse_{cap}.txt"))
        );
        assert_eq!(
            pcap_report(&msgs, true, false),
            text(&format!("parse_{cap}_quick.txt"))
        );
        assert_eq!(
            pcap_report(&msgs, false, true),
            text(&format!("parse_{cap}_harmonics.txt"))
        );
        checked += 1;
    }
    eprintln!("{checked} capture(s) checked");
}