//! Fig's Symbol and ZapfDingbats codes: what each stored byte stands for
//! (the character map, E5), and the reverse, so typing a Unicode character
//! in a Symbol-font text stores its Symbol byte.
//!
// Ported from fig2dev dev/gensvg.c (`symbolchar`, `dingbatchar`; xfig licence, see LICENSE-xfig).

/// gensvg.c `symbolchar[256]`: Unicode of each Fig Symbol code, 0 where none.
pub const SYMBOL_CHAR: [u32; 256] = [
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0020, 0x0021, 0x2200, 0x0023, 0x2203, 0x0025, 0x0026, 0x220B, 0x0028, 0x0029,
    0x2217, 0x002B, 0x002C, 0x2212, 0x002E, 0x002F, 0x0030, 0x0031, 0x0032, 0x0033, 0x0034, 0x0035, 0x0036, 0x0037,
    0x0038, 0x0039, 0x003A, 0x003B, 0x003C, 0x003D, 0x003E, 0x003F, 0x2245, 0x0391, 0x0392, 0x03A7, 0x0394, 0x0395,
    0x03A6, 0x0393, 0x0397, 0x0399, 0x03D1, 0x039A, 0x039B, 0x039C, 0x039D, 0x039F, 0x03A0, 0x0398, 0x03A1, 0x03A3,
    0x03A4, 0x03A5, 0x03C2, 0x03A9, 0x039E, 0x03A8, 0x0396, 0x005B, 0x2234, 0x005D, 0x22A5, 0x005F, 0xF8E5, 0x03B1,
    0x03B2, 0x03C7, 0x03B4, 0x03B5, 0x03D5, 0x03B3, 0x03B7, 0x03B9, 0x03D5, 0x03BA, 0x03BB, 0x03BC, 0x03BD, 0x03BF,
    0x03C0, 0x03B8, 0x03C1, 0x03C3, 0x03C4, 0x03C5, 0x03D6, 0x03C9, 0x03BE, 0x03C8, 0x03B6, 0x007B, 0x007C, 0x007D,
    0x223C, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x20AC, 0x03D2, 0x2032, 0x2264, 0x2044, 0x221E, 0x0192, 0x2663,
    0x2666, 0x2665, 0x2660, 0x2194, 0x2190, 0x2191, 0x2192, 0x2193, 0x00B0, 0x00B1, 0x2033, 0x2265, 0x00D7, 0x221D,
    0x2202, 0x2022, 0x00F7, 0x2260, 0x2261, 0x2248, 0x2026, 0xF8E6, 0xF8E7, 0x21B5, 0x2135, 0x2111, 0x211C, 0x2118,
    0x2297, 0x2295, 0x2205, 0x2229, 0x222A, 0x2283, 0x2287, 0x2284, 0x2282, 0x2286, 0x2208, 0x2209, 0x2220, 0x2207,
    0xF6DA, 0xF6D9, 0xF6DB, 0x220F, 0x221A, 0x22C5, 0x00AC, 0x2227, 0x2228, 0x21D4, 0x21D0, 0x21D1, 0x21D2, 0x21D3,
    0x25CA, 0x2329, 0xF8E8, 0xF8E9, 0xF8EA, 0x2211, 0xF8EB, 0xF8EC, 0xF8ED, 0xF8EE, 0xF8EF, 0xF8F0, 0xF8F1, 0xF8F2,
    0xF8F3, 0xF8F4, 0x0000, 0x232A, 0x222B, 0x2320, 0xF8F5, 0x2321, 0xF8F6, 0xF8F7, 0xF8F8, 0xF8F9, 0xF8FA, 0xF8FB,
    0xF8FC, 0xF8FD, 0xF8FE, 0x0000,
];

/// gensvg.c `dingbatchar[256]`: Unicode of each Fig ZapfDingbats code, 0 where none.
pub const DINGBAT_CHAR: [u32; 256] = [
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0020, 0x2701, 0x2702, 0x2703, 0x2704, 0x260E, 0x2706, 0x2707, 0x2708, 0x2709,
    0x261B, 0x261E, 0x270C, 0x270D, 0x270E, 0x270F, 0x2710, 0x2711, 0x2712, 0x2713, 0x2714, 0x2715, 0x2716, 0x2717,
    0x2718, 0x2719, 0x271A, 0x271B, 0x271C, 0x271D, 0x271E, 0x271F, 0x2720, 0x2721, 0x2722, 0x2723, 0x2724, 0x2725,
    0x2726, 0x2727, 0x2605, 0x2729, 0x272A, 0x272B, 0x272C, 0x272D, 0x272E, 0x272F, 0x2730, 0x2731, 0x2732, 0x2733,
    0x2734, 0x2735, 0x2736, 0x2737, 0x2738, 0x2739, 0x273A, 0x273B, 0x273C, 0x273D, 0x273E, 0x273F, 0x2740, 0x2741,
    0x2742, 0x2743, 0x2744, 0x2745, 0x2746, 0x2747, 0x2748, 0x2749, 0x274A, 0x274B, 0x25CF, 0x274D, 0x25A0, 0x274F,
    0x2750, 0x2751, 0x2752, 0x25B2, 0x25BC, 0x25C6, 0x2756, 0x25D7, 0x2758, 0x2759, 0x275A, 0x275B, 0x275C, 0x275D,
    0x275E, 0x0000, 0xF8D7, 0xF8D8, 0xF8D9, 0xF8DA, 0xF8DB, 0xF8DC, 0xF8DD, 0xF8DE, 0xF8DF, 0xF8E0, 0xF8E1, 0xF8E2,
    0xF8E3, 0xF8E4, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000,
    0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x2761, 0x2762, 0x2763, 0x2764, 0x2765, 0x2766, 0x2767,
    0x2663, 0x2666, 0x2665, 0x2660, 0x2460, 0x2461, 0x2462, 0x2463, 0x2464, 0x2465, 0x2466, 0x2467, 0x2468, 0x2469,
    0x2776, 0x2777, 0x2778, 0x2779, 0x277A, 0x277B, 0x277C, 0x277D, 0x277E, 0x277F, 0x2780, 0x2781, 0x2782, 0x2783,
    0x2784, 0x2785, 0x2786, 0x2787, 0x2788, 0x2789, 0x278A, 0x278B, 0x278C, 0x278D, 0x278E, 0x278F, 0x2790, 0x2791,
    0x2792, 0x2793, 0x2794, 0x2192, 0x2194, 0x2195, 0x2798, 0x2799, 0x279A, 0x279B, 0x279C, 0x279D, 0x279E, 0x279F,
    0x27A0, 0x27A1, 0x27A2, 0x27A3, 0x27A4, 0x27A5, 0x27A6, 0x27A7, 0x27A8, 0x27A9, 0x27AA, 0x27AB, 0x27AC, 0x27AD,
    0x27AE, 0x27AF, 0x0000, 0x27B1, 0x27B2, 0x27B3, 0x27B4, 0x27B5, 0x27B6, 0x27B7, 0x27B8, 0x27B9, 0x27BA, 0x27BB,
    0x27BC, 0x27BD, 0x27BE, 0x0000,
];

/// The Fig font numbers of Symbol and ZapfDingbats in PostScript mode.
pub const FONT_SYMBOL: i32 = 32;
/// ZapfDingbats.
pub const FONT_DINGBATS: i32 = 34;

/// The table of a font, if it is Symbol or ZapfDingbats.
pub fn table_for(font: i32) -> Option<&'static [u32; 256]> {
    match font {
        FONT_SYMBOL => Some(&SYMBOL_CHAR),
        FONT_DINGBATS => Some(&DINGBAT_CHAR),
        _ => None,
    }
}

/// Unicode shown for a stored byte of a Symbol or Dingbats text.
pub fn code_to_unicode(font: i32, code: u8) -> Option<char> {
    let t = table_for(font)?;
    t.get(usize::from(code))
        .filter(|&&u| u != 0)
        .and_then(|&u| char::from_u32(u))
}

/// The char that stores `c` for `font`: for Symbol and Dingbats the char
/// whose code is the glyph's byte (the model keeps text bytes below 256 as
/// chars of that value, as fig2dev reads them); `None` when the font has no
/// such glyph. For other fonts `c` stays as it is.
pub fn store_char(font: i32, c: char) -> Option<char> {
    let Some(t) = table_for(font) else {
        return Some(c);
    };
    let u = u32::from(c);
    let pos = t.iter().position(|&x| x != 0 && x == u)?;
    u8::try_from(pos).ok().map(char::from)
}

/// All glyphs of a Symbol or Dingbats font as (stored code, Unicode).
pub fn glyphs(font: i32) -> Vec<(u8, char)> {
    (0..=255u8)
        .filter_map(|b| code_to_unicode(font, b).map(|c| (b, c)))
        .collect()
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn sum_is_symbol_0xe5() {
        assert_eq!(store_char(FONT_SYMBOL, '∑'), Some('\u{e5}'));
        assert_eq!(code_to_unicode(FONT_SYMBOL, 0xe5), Some('∑'));
        assert_eq!(store_char(0, '∑'), Some('∑'));
        assert_eq!(store_char(FONT_SYMBOL, 'é'), None);
    }
}

.