gribberish 1.1.1

use super::grib_section::GribSection;
use crate::utils::read_u64_from_bytes;
use gribberish_macros::{DisplayDescription, FromValue};
use std::str;

fn validate_indicator_section(data: &[u8]) -> bool {
    match str::from_utf8(&data[0..4]) {
        Ok(s) => s == "GRIB",
        _ => false,
    }
}

#[repr(u8)]
#[derive(Eq, Clone, PartialEq, Debug, DisplayDescription, FromValue)]
pub enum Discipline {
    Meteorological = 0,
    Hydrological = 1,
    LandSurface = 2,
    Space = 3,
    Oceanographic = 10,
    MultiRadarMultiSensor = 209,
    Missing = 255,
}

pub struct IndicatorSection<'a> {
    data: &'a [u8],
}

impl<'a> IndicatorSection<'a> {
    pub fn from_data(data: &'a [u8]) -> Self {
        IndicatorSection { data }
    }

    pub fn is_indicator_section(data: &[u8], offset: usize) -> bool {
        validate_indicator_section(&data[offset..offset + 4])
    }

    pub fn valid(&self) -> bool {
        validate_indicator_section(&self.data[0..4])
    }

    pub fn discipline_value(&self) -> u8 {
        self.data[6]
    }

    pub fn discipline(&self) -> Discipline {
        self.data[6].into()
    }

    pub fn edition(&self) -> u8 {
        self.data[7]
    }

    pub fn total_length(&self) -> u64 {
        read_u64_from_bytes(self.data, 8).unwrap_or(0) as u64
    }
}

impl<'a> GribSection for IndicatorSection<'a> {
    fn len(&self) -> usize {
        16
    }

    fn number(&self) -> u8 {
        0
    }
}

#[cfg(test)]
mod tests {
    #[test]
    fn read_indicator() {
        use super::{Discipline, IndicatorSection};

        let raw = [
            0x47u8, 0x52, 0x49, 0x42, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
            0x00, 0xb3,
        ];
        let indicator = IndicatorSection::from_data(&raw);
        assert!(indicator.valid());
        assert!(indicator.discipline() == Discipline::Meteorological);
    }
}