use serde_json::Value;

const FONT_5X7_JSON: &str = include_str!("../../assets/fonts/5x7.json");

pub struct Font {
    // pub name: String,
    // pub font_json: String,
    pub font_parsed: Value,
}

/// Return the embedded font JSON by string key
pub fn get_font_json(name: &str) -> Option<&'static str> {
    match name {
        "5x7" => Some(FONT_5X7_JSON),
        _ => None,
    }
}

impl Font {
    pub fn new(name: &str) -> Self {
        let font_json = get_font_json(name)
            .unwrap_or_else(|| panic!("Unknown font: {}", name))
            .to_string();

        let font_parsed: Value = serde_json::from_str(&font_json).unwrap();

        return Self {
            // name: name.to_string(),
            // font_json,
            font_parsed,
        };
    }

    pub fn get_char_bitmap(&self, index: u64) -> Option<Vec<Vec<u8>>> {
        let bytes = self
            .font_parsed
            .get("data")?
            .as_array()?
            .iter()
            .find(|entry| entry.get("n").map_or(false, |n| n == index))
            .and_then(|character| {
                character.get("b")?.as_array().map(|arr| {
                    arr.iter()
                        .filter_map(|val| val.as_u64())
                        .map(|n| n as u8)
                        .collect::<Vec<u8>>()
                })
            })?;

        let bits = bytes
            .iter()
            .flat_map(|&byte| (0..8).rev().map(move |i| (byte >> i) & 1))
            .collect::<Vec<u8>>();

        let char_matrix = bits.chunks(5).map(|chunk| chunk.to_vec()).collect();

        Some(char_matrix)
    }
}