//! The missing-input rule of `support/require_vectors.rs`, checked in the
//! environment it is about.
//!
//! The vector tests' CI jobs always set `WAI_REQUIRE_SOTA_VECTORS=1`, so those runs
//! never exercise what the helpers do WITHOUT the switch: that a variable naming a
//! test's inputs still makes them required, and that a test skips only when no
//! variable names what is missing (an unset variable, or an absent or incomplete
//! default location). These tests check that rule directly. Each case starts this
//! test binary again as a child process running the ignored `probe` test, with the
//! switch and the input variables set exactly as the case needs (and every other
//! one removed, so the parent's environment cannot leak in), then checks whether
//! the child passed or failed and what it printed.
//!
//! Their inputs are scratch directories and small files that each case creates
//! under the system temporary directory, so these tests never skip.

#[path = "support/require_vectors.rs"]
mod require_vectors;

use std::path::PathBuf;
use std::process::Command;

/// Which helper the probe runs: `dir` (`env_dir` + `load_all`, as the int_hyper
/// tests use them) or `paths` (`env_paths`, as the JPEG-AI tests use it).
const MODE: &str = "WAI_RV_PROBE";
/// The default directory the probe passes to `env_dir`.
const DEFAULT: &str = "WAI_RV_PROBE_DEFAULT";
/// The directory variable the probe reads, as `int_hyper_synth` does.
const DIR_VAR: &str = "WAI_SOTA_INT_DIR";
/// The two path variables the probe reads, as the JPEG-AI tests read three.
const PATH_VAR: &str = "WAI_JPEGAI_CODESTREAM";
const PATH_VAR2: &str = "WAI_JPEGAI_NORM";
/// The one input file the `dir` probe needs.
const INPUT: &str = "cond.json";

/// Runs one helper the way a vector test does and prints what it returned. It is
/// only meaningful in a child started by [`run`], with the environment [`run`]
/// gives it; run any other way, it returns without doing anything.
#[test]
#[ignore = "a probe that the other tests in this file run in a child process"]
fn probe() {
    let Ok(mode) = std::env::var(MODE) else {
        return;
    };
    let loaded = match mode.as_str() {
        "dir" => {
            let default = std::env::var(DEFAULT).expect("the default directory");
            let d = require_vectors::env_dir("probe", DIR_VAR, &default, "the probe");
            require_vectors::load_all("probe", &d, [INPUT], "the probe").is_some()
        }
        "paths" => require_vectors::env_paths("probe", [PATH_VAR, PATH_VAR2], "the probe").is_some(),
        other => panic!("unknown probe mode {other}"),
    };
    println!(
        "probe: {}",
        if loaded {
            "inputs loaded"
        } else {
            "returned without inputs"
        }
    );
}

/// What a probe run did.
struct Outcome {
    passed: bool,
    /// The child's stdout followed by its stderr.
    out: String,
}

impl Outcome {
    /// The probe passed because it found nothing to check: the loud skip.
    fn assert_skipped_loudly(&self) {
        assert!(self.passed, "expected a skip, got a failure:\n{}", self.out);
        assert!(
            self.out.contains("probe: returned without inputs"),
            "{}",
            self.out
        );
        // The banner CI's backstop looks for, so a skip is never read as a pass.
        assert!(
            self.out.contains("SKIPPED") && self.out.contains("NOT VERIFIED"),
            "{}",
            self.out
        );
    }

    fn assert_failed_with(&self, why: &str) {
        assert!(
            !self.passed,
            "expected a failure naming {why:?}, got a pass:\n{}",
            self.out
        );
        assert!(
            self.out.contains(why),
            "the failure does not say {why:?}:\n{}",
            self.out
        );
    }
}

/// Runs the probe in a child process in `mode`, with `env` set and the switch and
/// every input variable otherwise removed.
fn run(mode: &str, env: &[(&str, &str)]) -> Outcome {
    let exe = std::env::current_exe().expect("this test binary");
    let mut cmd = Command::new(exe);
    cmd.args([
        "probe",
        "--exact",
        "--ignored",
        "--nocapture",
        "--test-threads=1",
    ]);
    for v in [require_vectors::SWITCH, MODE, DEFAULT, DIR_VAR, PATH_VAR, PATH_VAR2] {
        cmd.env_remove(v);
    }
    cmd.env(MODE, mode);
    for (k, v) in env {
        cmd.env(k, v);
    }
    let o = cmd.output().expect("start the probe");
    let out = format!(
        "{}{}",
        String::from_utf8_lossy(&o.stdout),
        String::from_utf8_lossy(&o.stderr)
    );
    // A filter that matched nothing would also exit 0.
    assert!(
        out.contains("running 1 test"),
        "the probe did not run:\n{out}"
    );
    Outcome {
        passed: o.status.success(),
        out,
    }
}

/// A scratch directory unique to one test case, removed when dropped.
struct Scratch(PathBuf);

impl Scratch {
    fn new(case: &str) -> Scratch {
        let p = std::env::temp_dir().join(format!(
            "wai-require-vectors-rule-{}-{case}",
            std::process::id()
        ));
        let _ = std::fs::remove_dir_all(&p);
        std::fs::create_dir_all(&p).expect("create the scratch directory");
        Scratch(p)
    }

    /// A path inside the scratch directory, not created.
    fn at(&self, name: &str) -> String {
        self.0
            .join(name)
            .to_str()
            .expect("a UTF-8 temp path")
            .to_owned()
    }
}

impl Drop for Scratch {
    fn drop(&mut self) {
        let _ = std::fs::remove_dir_all(&self.0);
    }
}

// ---- without the switch ----

#[test]
fn without_the_switch_a_named_directory_that_does_not_exist_fails() {
    let s = Scratch::new("dir-missing");
    let (named, default) = (s.at("not-there"), s.at("default"));
    run("dir", &[(DIR_VAR, &named), (DEFAULT, &default)]).assert_failed_with("is not a directory");
}

#[test]
fn without_the_switch_a_named_path_that_is_a_file_fails_as_a_directory() {
    let s = Scratch::new("dir-is-file");
    let (named, default) = (s.at("a-file"), s.at("default"));
    std::fs::write(&named, b"{}").unwrap();
    run("dir", &[(DIR_VAR, &named), (DEFAULT, &default)]).assert_failed_with("is not a directory");
}

#[test]
fn without_the_switch_a_named_empty_directory_fails() {
    // The case this file was written for: the directory exists, so only the
    // missing file can fail the run.
    let s = Scratch::new("dir-empty");
    let (named, default) = (s.at("vectors"), s.at("default"));
    std::fs::create_dir(&named).unwrap();
    run("dir", &[(DIR_VAR, &named), (DEFAULT, &default)])
        .assert_failed_with(&format!("{DIR_VAR} names this directory"));
}

#[test]
fn without_the_switch_an_unset_or_empty_directory_variable_skips_on_an_absent_default() {
    let s = Scratch::new("dir-default");
    let default = s.at("default");
    run("dir", &[(DEFAULT, &default)]).assert_skipped_loudly();
    run("dir", &[(DIR_VAR, ""), (DEFAULT, &default)]).assert_skipped_loudly();
}

#[test]
fn without_the_switch_an_incomplete_default_directory_skips() {
    let s = Scratch::new("dir-default-empty");
    let default = s.at("default");
    std::fs::create_dir(&default).unwrap();
    run("dir", &[(DEFAULT, &default)]).assert_skipped_loudly();
}

#[test]
fn a_named_directory_holding_the_input_loads_it() {
    // The positive control: without it, a probe that always failed would make the
    // failure cases above pass for the wrong reason.
    let s = Scratch::new("dir-full");
    let (named, default) = (s.at("vectors"), s.at("default"));
    std::fs::create_dir(&named).unwrap();
    std::fs::write(PathBuf::from(&named).join(INPUT), b"{}").unwrap();
    let o = run("dir", &[(DIR_VAR, &named), (DEFAULT, &default)]);
    assert!(
        o.passed && o.out.contains("probe: inputs loaded"),
        "{}",
        o.out
    );
    assert!(!o.out.contains("NOT VERIFIED"), "{}", o.out);
}

#[test]
fn without_the_switch_a_path_variable_naming_nothing_fails() {
    let s = Scratch::new("path-missing");
    let other = s.at("norm.json");
    std::fs::write(&other, b"{}").unwrap();
    run("paths", &[(PATH_VAR, &s.at("not-there")), (PATH_VAR2, &other)])
        .assert_failed_with("does not exist");
    // env_paths has no default: an empty value names no existing path.
    run("paths", &[(PATH_VAR, ""), (PATH_VAR2, &other)]).assert_failed_with("does not exist");
}

#[test]
fn without_the_switch_a_path_variable_naming_nothing_fails_when_another_is_unset() {
    // The other variable being unset would end the test as a skip; the one that
    // names a missing path must fail it first.
    let s = Scratch::new("path-missing-partial");
    run("paths", &[(PATH_VAR, &s.at("not-there"))]).assert_failed_with("does not exist");
    run("paths", &[(PATH_VAR2, &s.at("not-there"))]).assert_failed_with("does not exist");
}

#[test]
fn without_the_switch_an_unset_path_variable_skips() {
    run("paths", &[]).assert_skipped_loudly();
    // One set to a file that exists, the other unset: nothing named is missing.
    let s = Scratch::new("path-partial");
    let file = s.at("codestream.bin");
    std::fs::write(&file, b"x").unwrap();
    run("paths", &[(PATH_VAR, &file)]).assert_skipped_loudly();
}

#[test]
fn path_variables_naming_files_that_exist_load_them() {
    // The positive control for `env_paths`, as the directory one is for `env_dir`.
    let s = Scratch::new("path-full");
    let (a, b) = (s.at("codestream.bin"), s.at("norm.json"));
    std::fs::write(&a, b"x").unwrap();
    std::fs::write(&b, b"{}").unwrap();
    let o = run("paths", &[(PATH_VAR, &a), (PATH_VAR2, &b)]);
    assert!(
        o.passed && o.out.contains("probe: inputs loaded"),
        "{}",
        o.out
    );
    assert!(!o.out.contains("NOT VERIFIED"), "{}", o.out);
}

#[test]
fn switch_values_that_leave_it_off_behave_as_unset() {
    let s = Scratch::new("switch-off");
    let default = s.at("default");
    for off in ["", "0", "false", "no", "FALSE", " no "] {
        run(
            "dir",
            &[(require_vectors::SWITCH, off), (DEFAULT, &default)],
        )
        .assert_skipped_loudly();
    }
}

// ---- with the switch ----

#[test]
fn with_the_switch_an_absent_default_fails() {
    let s = Scratch::new("switch-on");
    let default = s.at("default");
    for on in ["1", "true", "yes"] {
        run("dir", &[(require_vectors::SWITCH, on), (DEFAULT, &default)])
            .assert_failed_with("a missing input is a failure, not a skip");
        run("paths", &[(require_vectors::SWITCH, on)])
            .assert_failed_with("a missing input is a failure, not a skip");
    }
}