shaum 0.1.1

A Fiqh-compliant engine for determining Islamic fasting (Shaum) status. accurately identifies Wajib, Sunnah, Makruh, and Haram fasting days based on Hijri calendar rules.
Documentation 
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use chrono::{Datelike, NaiveDate, Weekday};
use crate::calendar::{to_hijri, get_hijri_month_name};
use crate::types::{FastingAnalysis, FastingStatus, FastingType};

pub fn check(g_date: NaiveDate, adjustment: i64) -> FastingAnalysis {
    let h_date = to_hijri(g_date, adjustment);
    let h_month = h_date.month();
    let h_day = h_date.day();
    let weekday = g_date.weekday();

    let mut types = Vec::new();
    let mut status = FastingStatus::Mubah;

    // --- 1. Haram Checks (Absolute Priority) ---
    // Eid al-Fitr
    if h_month == 10 && h_day == 1 {
        types.push(FastingType::EidAlFitr);
        return FastingAnalysis::new(g_date, FastingStatus::Haram, types)
            .with_description("Haram to fast on Eid al-Fitr (1 Shawwal).");
    }

    // Eid al-Adha
    if h_month == 12 && h_day == 10 {
        types.push(FastingType::EidAlAdha);
        return FastingAnalysis::new(g_date, FastingStatus::Haram, types)
            .with_description("Haram to fast on Eid al-Adha (10 Dhu al-Hijjah).");
    }

    // Tashriq Days
    if h_month == 12 && (11..=13).contains(&h_day) {
        types.push(FastingType::Tashriq);
        return FastingAnalysis::new(g_date, FastingStatus::Haram, types)
            .with_description(format!("Haram to fast on Days of Tashriq ({} Dhu al-Hijjah).", h_day));
    }

    // --- 2. Wajib Checks ---
    if h_month == 9 {
        types.push(FastingType::Ramadhan);
        // Even if it's Monday/Thursday, Ramadhan overrides Sunnah intention usually, 
        // but technically it's still Monday. We'll add Monday too if applicable, but Status is Wajib.
        status = FastingStatus::Wajib;
    }

    // --- 3. Sunnah Checks ---
    
    // Arafah (9 Dhu al-Hijjah)
    if h_month == 12 && h_day == 9 {
        types.push(FastingType::Arafah);
        if !status.is_wajib() { status = FastingStatus::SunnahMuakkadah; }
    }

    // Ashura (10 Muharram)
    if h_month == 1 && h_day == 10 {
        types.push(FastingType::Ashura);
        if !status.is_wajib() { status = FastingStatus::SunnahMuakkadah; }
    }

    // Tasu'a (9 Muharram)
    if h_month == 1 && h_day == 9 {
        types.push(FastingType::Tasua);
        if !status.is_wajib() && status != FastingStatus::SunnahMuakkadah { 
            status = FastingStatus::Sunnah; 
        }
    }

    // Ayyamul Bidh (13, 14, 15) - EXCLUDING 13 Dhu al-Hijjah (Handled by Haram above)
    // We already returned if it was 13 Dhul Hijjah.
    if (13..=15).contains(&h_day) {
        types.push(FastingType::AyyamulBidh);
        if !status.is_wajib() && status < FastingStatus::Sunnah {
            status = FastingStatus::Sunnah;
        }
    }

    // Monday / Thursday
    match weekday {
        Weekday::Mon => {
            types.push(FastingType::Monday);
            if !status.is_wajib() && status < FastingStatus::Sunnah { status = FastingStatus::Sunnah; }
        },
        Weekday::Thu => {
            types.push(FastingType::Thursday);
            if !status.is_wajib() && status < FastingStatus::Sunnah { status = FastingStatus::Sunnah; }
        },
        _ => {}
    }

    // Shawwal (Month 10, excluding Day 1)
    if h_month == 10 && h_day > 1 {
        types.push(FastingType::Shawwal);
        if !status.is_wajib() && status < FastingStatus::Sunnah { status = FastingStatus::Sunnah; }
    }

    // --- 4. Makruh Checks (Friday/Saturday) ---
    // Only if Mubah (no other status assigned).
    // If it's Arafah (Sunnah) on Friday, it's not Makruh.
    // If it's Ramadhan (Wajib) on Saturday, it's not Makruh.
    if status == FastingStatus::Mubah {
        if weekday == Weekday::Fri {
            types.push(FastingType::FridayExclusive);
            status = FastingStatus::Makruh;
        } else if weekday == Weekday::Sat {
            types.push(FastingType::SaturdayExclusive);
            status = FastingStatus::Makruh;
        }
    }

    FastingAnalysis::new(g_date, status, types)
        .with_description(format!("Hijri Date: {} {} {}", h_day, get_hijri_month_name(h_month), h_date.year()))
}