use crate::prelude::*;
use unicode_width::UnicodeWidthStr as _;

pub(crate) fn render(screen: &vt100::Screen) -> Node<crate::Msg> {
    let (rows, cols) = screen.size();
    let (cursor_row, cursor_col) = screen.cursor_position();

    let mut grid = vec![];
    for row_idx in 0..rows {
        let mut row = vec![];
        for col_idx in 0..cols {
            let cell = screen.cell(row_idx, col_idx).unwrap();

            let mut contents = cell.contents();
            // if we don't use a non-breaking space for cells with no
            // foreground contents, the table layout may just collapse those
            // cells. we can't just set a fixed height because there's no way
            // (that i'm aware of) in css to set a box to have a fixed height
            // that is the same as the line height of the current font.
            if contents.trim().is_empty() || contents.width() == 0 {
                contents = "\u{00a0}".to_string();
            }

            row.push(seed::td![
                seed::attrs! { At::Class => "cell" },
                style_for_cell(
                    cell,
                    cursor_row == row_idx
                        && cursor_col == col_idx
                        && !screen.hide_cursor()
                ),
                contents
            ])
        }
        grid.push(seed::tr![seed::attrs! { At::Class => "row" }, row]);
    }

    seed::table![seed::attrs! { At::Class => "grid" }, grid]
}

fn style_for_cell(
    cell: &vt100::Cell,
    is_cursor: bool,
) -> seed::dom_types::Style {
    let mut fgcolor = cell.fgcolor();
    let mut bgcolor = cell.bgcolor();
    if is_cursor {
        fgcolor = vt100::Color::Rgb(0, 0, 0);
        bgcolor = vt100::Color::Rgb(0, 0xff, 0);
    } else if cell.inverse() {
        if fgcolor == bgcolor {
            fgcolor = vt100::Color::Rgb(0, 0, 0);
            bgcolor = vt100::Color::Rgb(0xd3, 0xd3, 0xd3);
        } else {
            std::mem::swap(&mut fgcolor, &mut bgcolor);
        }
    }
    seed::style! {
        St::Color => color(fgcolor, cell.bold()),
        St::BackgroundColor => color(bgcolor, false),
        St::FontStyle => if cell.italic() { "italic" } else { "normal" },
        St::TextDecoration => if cell.underline() {
            "underline"
        } else {
            "none"
        },
    }
}

fn color(color: vt100::Color, bright: bool) -> Option<String> {
    match color {
        vt100::Color::Default => None,
        vt100::Color::Idx(n) => Some(indexed_color(n, bright).to_string()),
        vt100::Color::Rgb(r, g, b) => {
            Some(format!("#{:02x}{:02x}{:02x}", r, g, b))
        }
    }
}

fn indexed_color(mut idx: u8, bright: bool) -> &'static str {
    if idx < 8 && bright {
        idx += 8;
    }

    match idx {
        0 => "#000000",
        1 => "#800000",
        2 => "#008000",
        3 => "#808000",
        4 => "#000080",
        5 => "#800080",
        6 => "#008080",
        7 => "#c0c0c0",
        8 => "#808080",
        9 => "#ff0000",
        10 => "#00ff00",
        11 => "#ffff00",
        12 => "#0000ff",
        13 => "#ff00ff",
        14 => "#00ffff",
        15 => "#ffffff",
        16 => "#000000",
        17 => "#00005f",
        18 => "#000087",
        19 => "#0000af",
        20 => "#0000d7",
        21 => "#0000ff",
        22 => "#005f00",
        23 => "#005f5f",
        24 => "#005f87",
        25 => "#005faf",
        26 => "#005fd7",
        27 => "#005fff",
        28 => "#008700",
        29 => "#00875f",
        30 => "#008787",
        31 => "#0087af",
        32 => "#0087d7",
        33 => "#0087ff",
        34 => "#00af00",
        35 => "#00af5f",
        36 => "#00af87",
        37 => "#00afaf",
        38 => "#00afd7",
        39 => "#00afff",
        40 => "#00d700",
        41 => "#00d75f",
        42 => "#00d787",
        43 => "#00d7af",
        44 => "#00d7d7",
        45 => "#00d7ff",
        46 => "#00ff00",
        47 => "#00ff5f",
        48 => "#00ff87",
        49 => "#00ffaf",
        50 => "#00ffd7",
        51 => "#00ffff",
        52 => "#5f0000",
        53 => "#5f005f",
        54 => "#5f0087",
        55 => "#5f00af",
        56 => "#5f00d7",
        57 => "#5f00ff",
        58 => "#5f5f00",
        59 => "#5f5f5f",
        60 => "#5f5f87",
        61 => "#5f5faf",
        62 => "#5f5fd7",
        63 => "#5f5fff",
        64 => "#5f8700",
        65 => "#5f875f",
        66 => "#5f8787",
        67 => "#5f87af",
        68 => "#5f87d7",
        69 => "#5f87ff",
        70 => "#5faf00",
        71 => "#5faf5f",
        72 => "#5faf87",
        73 => "#5fafaf",
        74 => "#5fafd7",
        75 => "#5fafff",
        76 => "#5fd700",
        77 => "#5fd75f",
        78 => "#5fd787",
        79 => "#5fd7af",
        80 => "#5fd7d7",
        81 => "#5fd7ff",
        82 => "#5fff00",
        83 => "#5fff5f",
        84 => "#5fff87",
        85 => "#5fffaf",
        86 => "#5fffd7",
        87 => "#5fffff",
        88 => "#870000",
        89 => "#87005f",
        90 => "#870087",
        91 => "#8700af",
        92 => "#8700d7",
        93 => "#8700ff",
        94 => "#875f00",
        95 => "#875f5f",
        96 => "#875f87",
        97 => "#875faf",
        98 => "#875fd7",
        99 => "#875fff",
        100 => "#878700",
        101 => "#87875f",
        102 => "#878787",
        103 => "#8787af",
        104 => "#8787d7",
        105 => "#8787ff",
        106 => "#87af00",
        107 => "#87af5f",
        108 => "#87af87",
        109 => "#87afaf",
        110 => "#87afd7",
        111 => "#87afff",
        112 => "#87d700",
        113 => "#87d75f",
        114 => "#87d787",
        115 => "#87d7af",
        116 => "#87d7d7",
        117 => "#87d7ff",
        118 => "#87ff00",
        119 => "#87ff5f",
        120 => "#87ff87",
        121 => "#87ffaf",
        122 => "#87ffd7",
        123 => "#87ffff",
        124 => "#af0000",
        125 => "#af005f",
        126 => "#af0087",
        127 => "#af00af",
        128 => "#af00d7",
        129 => "#af00ff",
        130 => "#af5f00",
        131 => "#af5f5f",
        132 => "#af5f87",
        133 => "#af5faf",
        134 => "#af5fd7",
        135 => "#af5fff",
        136 => "#af8700",
        137 => "#af875f",
        138 => "#af8787",
        139 => "#af87af",
        140 => "#af87d7",
        141 => "#af87ff",
        142 => "#afaf00",
        143 => "#afaf5f",
        144 => "#afaf87",
        145 => "#afafaf",
        146 => "#afafd7",
        147 => "#afafff",
        148 => "#afd700",
        149 => "#afd75f",
        150 => "#afd787",
        151 => "#afd7af",
        152 => "#afd7d7",
        153 => "#afd7ff",
        154 => "#afff00",
        155 => "#afff5f",
        156 => "#afff87",
        157 => "#afffaf",
        158 => "#afffd7",
        159 => "#afffff",
        160 => "#d70000",
        161 => "#d7005f",
        162 => "#d70087",
        163 => "#d700af",
        164 => "#d700d7",
        165 => "#d700ff",
        166 => "#d75f00",
        167 => "#d75f5f",
        168 => "#d75f87",
        169 => "#d75faf",
        170 => "#d75fd7",
        171 => "#d75fff",
        172 => "#d78700",
        173 => "#d7875f",
        174 => "#d78787",
        175 => "#d787af",
        176 => "#d787d7",
        177 => "#d787ff",
        178 => "#d7af00",
        179 => "#d7af5f",
        180 => "#d7af87",
        181 => "#d7afaf",
        182 => "#d7afd7",
        183 => "#d7afff",
        184 => "#d7d700",
        185 => "#d7d75f",
        186 => "#d7d787",
        187 => "#d7d7af",
        188 => "#d7d7d7",
        189 => "#d7d7ff",
        190 => "#d7ff00",
        191 => "#d7ff5f",
        192 => "#d7ff87",
        193 => "#d7ffaf",
        194 => "#d7ffd7",
        195 => "#d7ffff",
        196 => "#ff0000",
        197 => "#ff005f",
        198 => "#ff0087",
        199 => "#ff00af",
        200 => "#ff00d7",
        201 => "#ff00ff",
        202 => "#ff5f00",
        203 => "#ff5f5f",
        204 => "#ff5f87",
        205 => "#ff5faf",
        206 => "#ff5fd7",
        207 => "#ff5fff",
        208 => "#ff8700",
        209 => "#ff875f",
        210 => "#ff8787",
        211 => "#ff87af",
        212 => "#ff87d7",
        213 => "#ff87ff",
        214 => "#ffaf00",
        215 => "#ffaf5f",
        216 => "#ffaf87",
        217 => "#ffafaf",
        218 => "#ffafd7",
        219 => "#ffafff",
        220 => "#ffd700",
        221 => "#ffd75f",
        222 => "#ffd787",
        223 => "#ffd7af",
        224 => "#ffd7d7",
        225 => "#ffd7ff",
        226 => "#ffff00",
        227 => "#ffff5f",
        228 => "#ffff87",
        229 => "#ffffaf",
        230 => "#ffffd7",
        231 => "#ffffff",
        232 => "#080808",
        233 => "#121212",
        234 => "#1c1c1c",
        235 => "#262626",
        236 => "#303030",
        237 => "#3a3a3a",
        238 => "#444444",
        239 => "#4e4e4e",
        240 => "#585858",
        241 => "#626262",
        242 => "#6c6c6c",
        243 => "#767676",
        244 => "#808080",
        245 => "#8a8a8a",
        246 => "#949494",
        247 => "#9e9e9e",
        248 => "#a8a8a8",
        249 => "#b2b2b2",
        250 => "#bcbcbc",
        251 => "#c6c6c6",
        252 => "#d0d0d0",
        253 => "#dadada",
        254 => "#e4e4e4",
        255 => "#eeeeee",
    }
}