//! Tests for the sandboxed `os` table.
//!
//! Ported from flowbox-rt's fb_lua os_tests. Unlike flowbox, this project
//! keeps the real Lua 5.5 os.date/os.time/os.difftime (flowbox used a
//! chrono-based shim), so a few edge cases differ - see individual tests.
//! os.sleep is async here and is covered by async_tests, not this file.

use std::time::{Duration, Instant};

#[test]
fn test_os_time_now() {
    let lua = super::lua();

    let result: i64 = lua.load(r#"return os.time()"#).eval().unwrap();
    let now = chrono::Utc::now().timestamp();
    assert!((result - now).abs() <= 5, "os.time() = {result}, expected ~{now}");
}

#[test]
fn test_os_time_from_table() {
    let lua = super::lua();

    // Round trip through local time - independent of the host timezone
    let ok: bool = lua
        .load(
            r#"
            local t = os.time({year = 2020, month = 1, day = 15, hour = 10, min = 30, sec = 20})
            local d = os.date("*t", t)
            return d.year == 2020 and d.month == 1 and d.day == 15
                and d.hour == 10 and d.min == 30 and d.sec == 20
            "#,
        )
        .eval()
        .unwrap();
    assert!(ok);

    // Out-of-range fields are normalized like mktime; hour defaults to 12
    let ok: bool = lua
        .load(
            r#"
            local a = os.time({year = 2020, month = 14, day = 1})
            local b = os.time({year = 2021, month = 2, day = 1})
            return a == b
            "#,
        )
        .eval()
        .unwrap();
    assert!(ok);

    // The normalized fields are written back into the table
    let ok: bool = lua
        .load(
            r#"
            local tbl = {year = 2020, month = 14, day = 1}
            os.time(tbl)
            return tbl.year == 2021 and tbl.month == 2 and tbl.day == 1
                and tbl.hour == 12 and tbl.wday == 2 -- 2021-02-01 was a Monday
            "#,
        )
        .eval()
        .unwrap();
    assert!(ok);

    // Missing mandatory field is an error
    let ok: bool = lua.load(r#"return (pcall(os.time, {year = 2020}))"#).eval().unwrap();
    assert!(!ok);
}

#[test]
fn test_os_date_format() {
    let lua = super::lua();

    let result: String = lua.load(r#"return os.date("!%Y-%m-%dT%H:%M:%S", 1000000000)"#).eval().unwrap();
    assert_eq!(result, "2001-09-09T01:46:40");

    // Epoch
    let result: String = lua.load(r#"return os.date("!%Y-%m-%d %H:%M:%S", 0)"#).eval().unwrap();
    assert_eq!(result, "1970-01-01 00:00:00");

    // Stock Lua difference: flowbox's chrono shim truncated float time values;
    // real Lua 5.5 requires an integer-representable time and raises an error.
    let ok: bool = lua.load(r#"return (pcall(os.date, "!%Y-%m-%d", 0.9))"#).eval().unwrap();
    assert!(!ok, "os.date with a fractional time value should raise in stock Lua");

    // Default format is %c, applied to the current time
    let result: String = lua.load(r#"return os.date()"#).eval().unwrap();
    assert!(!result.is_empty());

    // Invalid format specifier is an error, not garbage output
    let ok: bool = lua.load(r#"return (pcall(os.date, "%Q"))"#).eval().unwrap();
    assert!(!ok);
}

#[test]
fn test_os_date_table() {
    let lua = super::lua();

    // 2001-09-09T01:46:40Z was a Sunday, day 252 of the year
    let ok: bool = lua
        .load(
            r#"
            local d = os.date("!*t", 1000000000)
            return d.year == 2001 and d.month == 9 and d.day == 9
                and d.hour == 1 and d.min == 46 and d.sec == 40
                and d.wday == 1 and d.yday == 252
            "#,
        )
        .eval()
        .unwrap();
    assert!(ok);
}

/// os.clock is replaced with monotonic wall time since state creation.
#[test]
fn test_os_clock() {
    let start = Instant::now();
    let lua = super::lua();

    std::thread::sleep(Duration::from_millis(30));

    let clock: f64 = lua.load(r#"return os.clock()"#).eval().unwrap();
    assert!(
        (start.elapsed().as_secs_f64() - clock).abs() < 0.1,
        "Clock function works"
    );

    // 200 ms elapses, so it should be reported accurately
    std::thread::sleep(Duration::from_millis(200));
    let clock2: f64 = lua.load(r#"return os.clock()"#).eval().unwrap();

    assert!((clock2 - clock - 0.2) < 0.03, "Clock tracks time");
}

#[test]
fn test_os_difftime() {
    let lua = super::lua();

    let result: f64 = lua.load(r#"return os.difftime(10, 4)"#).eval().unwrap();
    assert_eq!(result, 6.0);

    let ok: bool = lua.load(r#"return (pcall(os.difftime, 10))"#).eval().unwrap();
    assert!(!ok);
}

#[test]
fn test_os_missing_dangerous_functions() {
    let lua = super::lua();

    let os_table = lua.globals().get::<mlua::Table>("os").unwrap();
    for name in ["execute", "exit", "getenv", "remove", "rename", "setlocale", "tmpname"] {
        assert!(
            !os_table.contains_key(name).unwrap(),
            "os.{name} should be removed from the sandbox"
        );
    }
}

#[test]
fn test_os_microtime() {
    let lua = super::lua();

    let result1: f64 = lua.load(r#"return os.microtime()"#).eval().unwrap();
    std::thread::sleep(Duration::from_millis(100));
    let result2: f64 = lua.load(r#"return os.microtime()"#).eval().unwrap();
    assert!(
        (result2 - result1 - 0.1).abs() < 0.03,
        "os.microtime() should return fractional seconds"
    );

    // It is a Unix timestamp
    let now = chrono::Utc::now().timestamp() as f64;
    assert!((result2 - now).abs() <= 5.0, "os.microtime() = {result2}, expected ~{now}");
}