splashboard 1.4.0

//! `clock_derived` — one-line values computed from today's date with no network or external
//! data. `kind` picks the computation: moon phase, zodiac, season, iso week, etc.

use chrono::{DateTime, Datelike, FixedOffset, Timelike};
use serde::Deserialize;

use crate::fetcher::{FetchContext, RealtimeFetcher, Safety};
use crate::payload::{Body, Payload, TextData};
use crate::render::Shape;
use crate::samples;

use super::common;

const SHAPES: &[Shape] = &[Shape::Text];

pub struct ClockDerivedFetcher;

#[derive(Debug, Default, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct Options {
    #[serde(default)]
    pub timezone: Option<String>,
    #[serde(default)]
    pub kind: Option<Kind>,
    /// Only meaningful when `kind = "season"`. `"north"` (default) applies Northern
    /// Hemisphere seasons (Mar–May = Spring, etc.); `"south"` flips them for users
    /// below the equator so April reads as Autumn instead of Spring.
    #[serde(default)]
    pub hemisphere: Option<Hemisphere>,
}

#[derive(Debug, Clone, Copy, Default, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "lowercase")]
pub enum Hemisphere {
    #[default]
    North,
    South,
}

#[derive(Debug, Clone, Copy, Default, Deserialize, PartialEq, Eq)]
#[serde(rename_all = "snake_case")]
pub enum Kind {
    #[default]
    TimeOfDay,
    MoonPhase,
    Zodiac,
    ChineseZodiac,
    Season,
    JpSeason,
    Rokuyou,
    IsoWeek,
    DayOfYear,
    JulianDay,
    UnixEpoch,
}

impl RealtimeFetcher for ClockDerivedFetcher {
    fn name(&self) -> &str {
        "clock_derived"
    }
    fn safety(&self) -> Safety {
        Safety::Safe
    }
    fn description(&self) -> &'static str {
        "A single value derived from today's date, picked by `kind` (time of day, moon phase, zodiac, chinese zodiac, season, Japanese seasonal term, rokuyou, ISO week, day of year, Julian day, Unix epoch). Use `clock_almanac` to show several of these together as one block."
    }
    fn shapes(&self) -> &[Shape] {
        SHAPES
    }
    fn sample_body(&self, shape: Shape) -> Option<Body> {
        match shape {
            Shape::Text => Some(samples::text("day 113 of 2026")),
            _ => None,
        }
    }
    fn compute(&self, ctx: &FetchContext) -> Payload {
        let opts: Options = match common::parse_options(ctx.options.as_ref()) {
            Ok(o) => o,
            Err(msg) => return common::placeholder(&msg),
        };
        let now = common::now_in(opts.timezone.as_deref());
        let line = invoke(
            &now,
            opts.kind.unwrap_or(Kind::TimeOfDay),
            opts.hemisphere.unwrap_or_default(),
        );
        Payload {
            icon: None,
            status: None,
            format: None,
            body: Body::Text(TextData { value: line }),
        }
    }
}

/// Dispatch a single kind against an already-resolved `now`. Shared with the
/// `clock_almanac` rollup so both fetchers stay in sync on formatting.
pub(crate) fn invoke(now: &DateTime<FixedOffset>, kind: Kind, hemisphere: Hemisphere) -> String {
    match kind {
        Kind::TimeOfDay => time_of_day(now).into(),
        Kind::MoonPhase => moon_phase(now),
        Kind::Zodiac => zodiac(now),
        Kind::ChineseZodiac => chinese_zodiac(now),
        Kind::Season => season(now, hemisphere),
        Kind::JpSeason => jp_season(now),
        Kind::Rokuyou => rokuyou(now),
        Kind::IsoWeek => iso_week(now),
        Kind::DayOfYear => format!("day {}", now.ordinal()),
        Kind::JulianDay => format!("JD {}", common::julian_day(now.date_naive())),
        Kind::UnixEpoch => now.timestamp().to_string(),
    }
}

fn time_of_day(now: &DateTime<FixedOffset>) -> &'static str {
    match now.hour() {
        5..=11 => "morning",
        12..=16 => "afternoon",
        17..=20 => "evening",
        _ => "night",
    }
}

fn moon_phase(now: &DateTime<FixedOffset>) -> String {
    // Conway's moon-phase approximation. Accuracy ±1 day, adequate for a splash widget.
    let (mut year, month, day) = (now.year(), now.month() as i32, now.day() as i32);
    let m = if month < 3 {
        year -= 1;
        month + 12
    } else {
        month
    };
    let c = (year / 100) as f64;
    let y = (year % 100) as f64;
    let jdn = (365.25 * (y + 4712.0)).floor() + (30.6 * (m as f64 + 1.0)).floor() + day as f64
        - (c * 0.75).floor()
        + c
        - 37.5;
    let phase = ((jdn - 2_451_550.1) / 29.530_588_853).rem_euclid(1.0);
    let idx = (phase * 8.0).floor() as usize % 8;
    let (glyph, name) = match idx {
        0 => ("🌑", "New"),
        1 => ("🌒", "Waxing Crescent"),
        2 => ("🌓", "First Quarter"),
        3 => ("🌔", "Waxing Gibbous"),
        4 => ("🌕", "Full"),
        5 => ("🌖", "Waning Gibbous"),
        6 => ("🌗", "Last Quarter"),
        _ => ("🌘", "Waning Crescent"),
    };
    format!("{glyph} {name}")
}

fn zodiac(now: &DateTime<FixedOffset>) -> String {
    let (m, d) = (now.month(), now.day());
    let (name, glyph) = match (m, d) {
        (3, 21..=31) | (4, 1..=19) => ("Aries", "♈"),
        (4, 20..=30) | (5, 1..=20) => ("Taurus", "♉"),
        (5, 21..=31) | (6, 1..=20) => ("Gemini", "♊"),
        (6, 21..=30) | (7, 1..=22) => ("Cancer", "♋"),
        (7, 23..=31) | (8, 1..=22) => ("Leo", "♌"),
        (8, 23..=31) | (9, 1..=22) => ("Virgo", "♍"),
        (9, 23..=30) | (10, 1..=22) => ("Libra", "♎"),
        (10, 23..=31) | (11, 1..=21) => ("Scorpio", "♏"),
        (11, 22..=30) | (12, 1..=21) => ("Sagittarius", "♐"),
        (12, 22..=31) | (1, 1..=19) => ("Capricorn", "♑"),
        (1, 20..=31) | (2, 1..=18) => ("Aquarius", "♒"),
        _ => ("Pisces", "♓"),
    };
    format!("{glyph} {name}")
}

fn chinese_zodiac(now: &DateTime<FixedOffset>) -> String {
    // 1900 = Rat; approximation ignores the lunar-new-year boundary.
    let animals = [
        ("Rat", "🐀"),
        ("Ox", "🐂"),
        ("Tiger", "🐅"),
        ("Rabbit", "🐇"),
        ("Dragon", "🐉"),
        ("Snake", "🐍"),
        ("Horse", "🐎"),
        ("Goat", "🐐"),
        ("Monkey", "🐒"),
        ("Rooster", "🐓"),
        ("Dog", "🐕"),
        ("Pig", "🐖"),
    ];
    let idx = ((now.year() - 1900).rem_euclid(12)) as usize;
    let (name, glyph) = animals[idx];
    format!("{glyph} {name}")
}

fn season(now: &DateTime<FixedOffset>, hemisphere: Hemisphere) -> String {
    let north = match now.month() {
        3..=5 => "Spring",
        6..=8 => "Summer",
        9..=11 => "Autumn",
        _ => "Winter",
    };
    match hemisphere {
        Hemisphere::North => north.into(),
        // Seasons are ~6 months shifted below the equator: April (Spring up north) is
        // Autumn in Sydney / Auckland / Buenos Aires.
        Hemisphere::South => match north {
            "Spring" => "Autumn",
            "Summer" => "Winter",
            "Autumn" => "Spring",
            _ => "Summer",
        }
        .into(),
    }
}

fn jp_season(now: &DateTime<FixedOffset>) -> String {
    // 二十四節気, fixed-date approximation (actual solar terms shift ±1 day year to year).
    const TERMS: &[(u32, u32, &str)] = &[
        (1, 6, "小寒"),
        (1, 20, "大寒"),
        (2, 4, "立春"),
        (2, 19, "雨水"),
        (3, 5, "啓蟄"),
        (3, 21, "春分"),
        (4, 5, "清明"),
        (4, 20, "穀雨"),
        (5, 5, "立夏"),
        (5, 21, "小満"),
        (6, 6, "芒種"),
        (6, 21, "夏至"),
        (7, 7, "小暑"),
        (7, 23, "大暑"),
        (8, 8, "立秋"),
        (8, 23, "処暑"),
        (9, 8, "白露"),
        (9, 23, "秋分"),
        (10, 8, "寒露"),
        (10, 24, "霜降"),
        (11, 7, "立冬"),
        (11, 22, "小雪"),
        (12, 7, "大雪"),
        (12, 22, "冬至"),
    ];
    let (m, d) = (now.month(), now.day());
    let mut current = "小寒";
    for &(tm, td, name) in TERMS {
        if (m, d) >= (tm, td) {
            current = name;
        }
    }
    current.into()
}

fn rokuyou(now: &DateTime<FixedOffset>) -> String {
    let jd = common::julian_day(now.date_naive());
    let idx = (jd.rem_euclid(6)) as usize;
    ["大安", "赤口", "先勝", "友引", "先負", "仏滅"][idx].into()
}

fn iso_week(now: &DateTime<FixedOffset>) -> String {
    let iso = now.iso_week();
    format!("{}-W{:02}", iso.year(), iso.week())
}

#[cfg(test)]
mod tests {
    use std::time::Duration;

    use chrono::{TimeZone, Utc};

    use super::*;

    fn at(y: i32, m: u32, d: u32, h: u32) -> DateTime<FixedOffset> {
        Utc.with_ymd_and_hms(y, m, d, h, 0, 0)
            .unwrap()
            .fixed_offset()
    }

    fn ctx(options: &str) -> FetchContext {
        FetchContext {
            widget_id: "d".into(),
            timeout: Duration::from_secs(1),
            shape: Some(Shape::Text),
            options: Some(toml::from_str(options).unwrap()),
            ..Default::default()
        }
    }

    #[test]
    fn time_of_day_afternoon_at_14h() {
        assert_eq!(time_of_day(&at(2026, 4, 22, 14)), "afternoon");
    }

    #[test]
    fn fetcher_exposes_catalog_surface() {
        let fetcher = ClockDerivedFetcher;
        assert_eq!(fetcher.name(), "clock_derived");
        assert_eq!(fetcher.safety(), Safety::Safe);
        assert_eq!(fetcher.default_shape(), Shape::Text);
        assert_eq!(fetcher.shapes(), SHAPES);
        assert!(fetcher.description().contains("moon phase"));
        assert!(matches!(
            fetcher.sample_body(Shape::Text),
            Some(Body::Text(_))
        ));
        assert!(fetcher.sample_body(Shape::Entries).is_none());
    }

    #[test]
    fn time_of_day_covers_remaining_buckets() {
        [(6, "morning"), (18, "evening"), (23, "night")]
            .into_iter()
            .for_each(|(hour, expected)| assert_eq!(time_of_day(&at(2026, 4, 22, hour)), expected));
    }

    #[test]
    fn zodiac_april_22_is_taurus() {
        assert!(zodiac(&at(2026, 4, 22, 12)).contains("Taurus"));
    }

    #[test]
    fn zodiac_covers_every_sign_boundary() {
        [
            ((3, 21), "Aries"),
            ((4, 20), "Taurus"),
            ((5, 21), "Gemini"),
            ((6, 21), "Cancer"),
            ((7, 23), "Leo"),
            ((8, 23), "Virgo"),
            ((9, 23), "Libra"),
            ((10, 23), "Scorpio"),
            ((11, 22), "Sagittarius"),
            ((12, 22), "Capricorn"),
            ((1, 20), "Aquarius"),
            ((2, 19), "Pisces"),
        ]
        .into_iter()
        .for_each(|((month, day), expected)| {
            assert!(zodiac(&at(2026, month, day, 12)).contains(expected));
        });
    }

    #[test]
    fn chinese_zodiac_2026_is_horse() {
        assert!(chinese_zodiac(&at(2026, 4, 22, 12)).contains("Horse"));
    }

    #[test]
    fn moon_phase_covers_january_rollover_and_all_labels() {
        [
            ((2026, 1, 6), "New"),
            ((2026, 1, 10), "Waxing Crescent"),
            ((2026, 1, 14), "First Quarter"),
            ((2026, 1, 17), "Waxing Gibbous"),
            ((2026, 1, 21), "Full"),
            ((2026, 1, 25), "Waning Gibbous"),
            ((2026, 1, 1), "Last Quarter"),
            ((2026, 1, 3), "Waning Crescent"),
        ]
        .into_iter()
        .for_each(|((year, month, day), expected)| {
            assert!(moon_phase(&at(year, month, day, 0)).contains(expected));
        });
    }

    #[test]
    fn season_summer_in_july_north() {
        assert_eq!(season(&at(2026, 7, 1, 0), Hemisphere::North), "Summer");
    }

    #[test]
    fn season_autumn_in_october_north() {
        assert_eq!(season(&at(2026, 10, 1, 0), Hemisphere::North), "Autumn");
    }

    #[test]
    fn season_winter_in_july_south() {
        assert_eq!(season(&at(2026, 7, 1, 0), Hemisphere::South), "Winter");
    }

    #[test]
    fn season_autumn_in_april_south() {
        assert_eq!(season(&at(2026, 4, 22, 0), Hemisphere::South), "Autumn");
    }

    #[test]
    fn season_defaults_to_north_without_option() {
        let p = ClockDerivedFetcher.compute(&ctx("kind = \"season\""));
        assert!(matches!(&p.body, Body::Text(_)));
        if let Body::Text(t) = p.body {
            assert!(["Spring", "Summer", "Autumn", "Winter"].contains(&t.value.as_str()));
        }
    }

    #[test]
    fn season_respects_south_hemisphere_option() {
        // Jan-Feb up north is Winter → Summer in the south. Pick a Jan date so the
        // flip is unambiguous regardless of when the test runs.
        let opts: Options = toml::from_str("kind = \"season\"\nhemisphere = \"south\"").unwrap();
        let now = at(2026, 1, 15, 0);
        assert_eq!(season(&now, opts.hemisphere.unwrap_or_default()), "Summer");
    }

    #[test]
    fn jp_season_april_22_is_穀雨() {
        assert_eq!(jp_season(&at(2026, 4, 22, 0)), "穀雨");
    }

    #[test]
    fn jp_season_before_first_term_keeps_default_label() {
        assert_eq!(jp_season(&at(2026, 1, 1, 0)), "小寒");
    }

    #[test]
    fn iso_week_formats_yyyy_w_nn() {
        let s = iso_week(&at(2026, 4, 22, 0));
        assert!(s.starts_with("2026-W"));
        assert_eq!(s.len(), 8);
    }

    #[test]
    fn rokuyou_returns_one_of_six_names() {
        let s = rokuyou(&at(2026, 4, 22, 0));
        assert!(["大安", "赤口", "先勝", "友引", "先負", "仏滅"].contains(&s.as_str()));
    }

    #[test]
    fn default_kind_is_time_of_day() {
        let p = ClockDerivedFetcher.compute(&ctx(""));
        assert!(matches!(p.body, Body::Text(_)));
    }

    #[test]
    fn compute_invalid_options_returns_placeholder() {
        let payload = ClockDerivedFetcher.compute(&ctx("kind = \"not-a-kind\""));
        assert!(matches!(&payload.body, Body::TextBlock(_)));
        if let Body::TextBlock(data) = payload.body {
            assert!(data.lines[0].contains("invalid options"));
            assert_eq!(data.lines[1], "check [widget.options] in config");
        }
    }

    #[test]
    fn invoke_dispatches_every_supported_kind() {
        let now = at(2026, 4, 22, 14);
        assert_eq!(
            invoke(&now, Kind::TimeOfDay, Hemisphere::North),
            "afternoon"
        );
        assert!(!invoke(&now, Kind::MoonPhase, Hemisphere::North).is_empty());
        assert!(invoke(&now, Kind::Zodiac, Hemisphere::North).contains("Taurus"));
        assert!(invoke(&now, Kind::ChineseZodiac, Hemisphere::North).contains("Horse"));
        assert_eq!(invoke(&now, Kind::Season, Hemisphere::North), "Spring");
        assert_eq!(invoke(&now, Kind::JpSeason, Hemisphere::North), "穀雨");
        assert!(
            ["大安", "赤口", "先勝", "友引", "先負", "仏滅"]
                .contains(&invoke(&now, Kind::Rokuyou, Hemisphere::North).as_str())
        );
        assert_eq!(invoke(&now, Kind::IsoWeek, Hemisphere::North), "2026-W17");
        assert_eq!(
            invoke(&now, Kind::DayOfYear, Hemisphere::North),
            format!("day {}", now.ordinal())
        );
        assert_eq!(
            invoke(&now, Kind::JulianDay, Hemisphere::North),
            format!("JD {}", common::julian_day(now.date_naive()))
        );
        assert_eq!(
            invoke(&now, Kind::UnixEpoch, Hemisphere::North),
            now.timestamp().to_string()
        );
    }

    #[test]
    fn moon_phase_kind_emits_nonempty_text() {
        let p = ClockDerivedFetcher.compute(&ctx("kind = \"moon_phase\""));
        assert!(matches!(&p.body, Body::Text(_)));
        if let Body::Text(d) = p.body {
            assert!(!d.value.is_empty());
        }
    }
}