//! Runs the `resolved` binary on the example scenes.

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

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

fn out_dir() -> PathBuf {
    let dir = PathBuf::from(env!("CARGO_TARGET_TMPDIR")).join("cli");
    std::fs::create_dir_all(&dir).unwrap();
    dir
}

/// Runs the binary from the repository root with `ASTROKIT_KERNELS` cleared, so the
/// kernel search falls back the way it does for someone who has not set it.
fn resolved(args: &[&str]) -> std::process::Output {
    Command::new(env!("CARGO_BIN_EXE_resolved"))
        .args(args)
        .current_dir(repo())
        .env_remove("ASTROKIT_KERNELS")
        .output()
        .unwrap()
}

/// Renders `scene` on `adapter` to a 16-bit PNG and returns its pixels as DN (the
/// file holds 12-bit DN shifted up by 4).
fn render(scene: &str, adapter: &str) -> image::ImageBuffer<image::Rgb<u16>, Vec<u16>> {
    render_at(scene, adapter, "L0")
}

/// A data directory whose Earth images and Moon map are small and uniform, for tests at
/// lighting L1 that do not need the real ones: loading those (16384 x 8192 each) takes
/// seconds in a debug build, and they are only there once fetched.
fn gray_earth() -> PathBuf {
    static DIR: std::sync::OnceLock<PathBuf> = std::sync::OnceLock::new();
    DIR.get_or_init(|| {
        let dir = out_dir().join("gray-data");
        std::fs::create_dir_all(dir.join("earth")).unwrap();
        let image = image::RgbImage::from_pixel(64, 32, image::Rgb([128; 3]));
        for month in 1..=12 {
            image
                .save(dir.join(format!("earth/bmng-2004-{month:02}.jpg")))
                .unwrap();
        }
        // A uniform Moon: I/F 0.06 (16-bit values of I/F x 100,000).
        std::fs::create_dir_all(dir.join("moon")).unwrap();
        image::ImageBuffer::<image::Luma<u16>, _>::from_pixel(64, 32, image::Luma([6000]))
            .save(dir.join("moon/wac-hapke-643.png"))
            .unwrap();
        dir
    })
    .clone()
}

/// [`render`] at lighting tier `lighting`, with Earth's images from [`gray_earth`].
fn render_at(
    scene: &str,
    adapter: &str,
    lighting: &str,
) -> image::ImageBuffer<image::Rgb<u16>, Vec<u16>> {
    let data = gray_earth();
    let out = out_dir().join(format!(
        "{}-{lighting}-{adapter}.png",
        Path::new(scene).file_stem().unwrap().to_str().unwrap()
    ));
    let preview = out.with_extension("preview.png");
    let result = resolved(&[
        "render",
        "--scene",
        scene,
        "--adapter",
        adapter,
        "--lighting",
        lighting,
        "--data",
        data.to_str().unwrap(),
        "--out",
        out.to_str().unwrap(),
        "--preview",
        preview.to_str().unwrap(),
    ]);
    assert!(
        result.status.success(),
        "{}",
        String::from_utf8_lossy(&result.stderr)
    );
    assert!(preview.is_file());
    let mut pixels = image::open(&out).unwrap().into_rgb16();
    for p in pixels.pixels_mut() {
        assert!(p.0.iter().all(|v| v & 0xf == 0), "low 4 bits are padding");
        p.0 = p.0.map(|v| v >> 4);
    }
    pixels
}

#[test]
fn example_scene_on_gpu_and_cpu() {
    let gpu = render("examples/scenes/boxwing.toml", "gpu");
    let cpu = render("examples/scenes/boxwing.toml", "cpu");
    assert_eq!(gpu.dimensions(), (1920, 1080));
    // The image center is on the sunlit gold bus: brighter in red than in blue.
    let [r, _, b] = gpu.get_pixel(960, 540).0;
    assert!(r > 500 && r > 2 * b, "{r} {b}");
    // Above the limb is empty space, which reads the 64 DN bias; below it, Earth's
    // dayside, lit and blue.
    assert_eq!(gpu.get_pixel(0, 0).0, [64; 3]);
    let [r, g, b] = gpu.get_pixel(0, 1079).0;
    assert!(r > 64 && g > r && b > g, "{r} {g} {b}");
    let differing = gpu
        .pixels()
        .zip(cpu.pixels())
        .filter(|(a, b)| a.0.iter().zip(b.0).any(|(x, y)| x.abs_diff(y) > 1))
        .count();
    // Only pixels on silhouette edges may land differently.
    assert!(
        differing < 500,
        "{differing} pixels differ between GPU and CPU"
    );
}

#[test]
fn pretty_previews_lift_the_darks_and_leave_space_black() {
    let preview = |pretty: bool| {
        let path = out_dir().join(format!("preview-pretty-{pretty}.png"));
        let path_str = path.to_str().unwrap();
        let mut args = vec![
            "render",
            "--scene",
            "examples/scenes/boxwing.toml",
            "--preview",
            path_str,
        ];
        if pretty {
            args.push("--pretty");
        }
        let result = resolved(&args);
        assert!(result.status.success(), "{result:?}");
        image::open(&path).unwrap().into_rgb8()
    };
    let (raw, pretty) = (preview(false), preview(true));
    // Space is the bias, black either way.
    assert_eq!(raw.get_pixel(0, 0).0, [0; 3]);
    assert_eq!(pretty.get_pixel(0, 0).0, [0; 3]);
    // Earth's dayside below the limb, well short of saturation: brighter when pretty.
    let (r, p) = (raw.get_pixel(0, 1079).0, pretty.get_pixel(0, 1079).0);
    assert!((0..3).all(|k| p[k] > r[k]), "raw {r:?}, pretty {p:?}");
}

#[cfg(feature = "astrokit")]
#[test]
fn lunar_eclipse_darkens_the_moon() {
    // Mid-totality: at L1 the whole Moon is in Earth's umbra and reads the bias. At L0
    // there are no eclipses on the bodies and it is a full Moon.
    let scene = "examples/scenes/lunar-eclipse.toml";
    let l0 = render_at(scene, "gpu", "L0");
    let l1 = render_at(scene, "gpu", "L1");
    assert!(
        l0.get_pixel(960, 540).0.iter().all(|&v| v > 150),
        "{:?}",
        l0.get_pixel(960, 540)
    );
    assert!(
        l1.pixels().all(|p| p.0 == [64; 3]),
        "every pixel at the bias"
    );
}

#[cfg(feature = "astrokit")]
#[test]
fn solar_eclipse_puts_the_umbra_at_greatest_eclipse() {
    // The camera looks straight down at the point of greatest eclipse from NASA's
    // bulletin (65.2 N 25.2 W, 17:46 UTC): at L1 it is in the Moon's umbra and reads the
    // bias, and the image corner, about 3500 km away in the penumbra, is brighter. At L0
    // the center is lit.
    let scene = "examples/scenes/solar-eclipse.toml";
    let l0 = render_at(scene, "gpu", "L0");
    let l1 = render_at(scene, "gpu", "L1");
    assert!(
        l0.get_pixel(960, 540).0.iter().all(|&v| v > 100),
        "{:?}",
        l0.get_pixel(960, 540)
    );
    assert_eq!(l1.get_pixel(960, 540).0, [64; 3]);
    let corner = l1.get_pixel(40, 1040).0;
    assert!(corner.iter().all(|&v| v > 70), "{corner:?}");
}

#[test]
fn lighting_l1_names_a_missing_moon_map() {
    // Earth's images but no Moon map: the error names the file and the script.
    let dir = out_dir().join("earth-only");
    std::fs::create_dir_all(dir.join("earth")).unwrap();
    std::fs::copy(
        gray_earth().join("earth/bmng-2004-07.jpg"),
        dir.join("earth/bmng-2004-07.jpg"),
    )
    .unwrap();
    let result = resolved(&[
        "render",
        "--scene",
        "examples/scenes/landsat8.toml",
        "--lighting",
        "L1",
        "--data",
        dir.to_str().unwrap(),
        "--preview",
        "x.png",
    ]);
    assert!(!result.status.success());
    let stderr = String::from_utf8_lossy(&result.stderr);
    assert!(
        stderr.contains("moon/wac-hapke-643.png") && stderr.contains("fetch-moon.py"),
        "{stderr}"
    );
}

#[test]
fn errors_are_reported() {
    let missing = resolved(&["render", "--scene", "no/such.toml", "--preview", "x.png"]);
    assert!(!missing.status.success());
    assert!(String::from_utf8_lossy(&missing.stderr).contains("no/such.toml"));

    let idle = resolved(&["render", "--scene", "examples/scenes/boxwing.toml"]);
    assert!(!idle.status.success());
    assert!(String::from_utf8_lossy(&idle.stderr).contains("nothing to do"));
}

#[cfg(feature = "astrokit")]
#[test]
fn missing_kernels_say_where_they_looked() {
    let result = resolved(&[
        "render",
        "--scene",
        "examples/scenes/full-moon.toml",
        "--kernels",
        "no/such/dir",
        "--preview",
        "x.png",
    ]);
    assert!(!result.status.success());
    let stderr = String::from_utf8_lossy(&result.stderr);
    assert!(
        stderr.contains("--kernels") && stderr.contains("no/such/dir"),
        "{stderr}"
    );
}

#[test]
fn lighting_l1_says_what_it_is_missing() {
    // Without an epoch or an earth_month, L1 cannot pick a month: boxwing.toml with its
    // [appearance] removed.
    let scene = out_dir().join("no-month.toml");
    let models = repo().join("examples/models").canonicalize().unwrap();
    let text = std::fs::read_to_string(repo().join("examples/scenes/boxwing.toml"))
        .unwrap()
        .replace("../models", models.to_str().unwrap())
        .replace("[appearance]\nearth_month = 7\n", "");
    assert!(!text.contains("earth_month"));
    std::fs::write(&scene, text).unwrap();
    let no_month = resolved(&[
        "render",
        "--scene",
        scene.to_str().unwrap(),
        "--lighting",
        "L1",
        "--preview",
        "x.png",
    ]);
    assert!(!no_month.status.success());
    let stderr = String::from_utf8_lossy(&no_month.stderr);
    assert!(stderr.contains("earth_month"), "{stderr}");

    // With a month but no data: the error names the file and the fetch script.
    let no_data = resolved(&[
        "render",
        "--scene",
        "examples/scenes/boxwing.toml",
        "--lighting",
        "L1",
        "--data",
        "no/such/dir",
        "--preview",
        "x.png",
    ]);
    assert!(!no_data.status.success());
    let stderr = String::from_utf8_lossy(&no_data.stderr);
    assert!(
        stderr.contains("bmng-2004-07.jpg") && stderr.contains("fetch-earth.sh"),
        "{stderr}"
    );

    let unknown = resolved(&[
        "render",
        "--scene",
        "examples/scenes/boxwing.toml",
        "--lighting",
        "L7",
        "--preview",
        "x.png",
    ]);
    assert!(!unknown.status.success());
}

#[test]
fn adapters_lists_something() {
    let result = resolved(&["adapters"]);
    assert!(result.status.success());
    assert!(!result.stdout.is_empty());
}