use rctree::Node;
use svg::{
    node::{
        element::{path::Data as PathData, Definitions, Path, Text, TextPath},
        Text as TextNode,
    },
    Document,
};
use usvg::Tree;

pub const HOUR_NAMES: [&str; 24] = [
    "Candle", "Ice", "Comet", "Thimble", "Root", "Mist", "Sprout", "Rainbow", "Worm", "Bud",
    "Blossom", "Ladybug", "Geese", "Dust", "Peach", "Fog", "Acorn", "Gourd", "Soup", "Crow",
    "Mushroom", "Thunder", "Frost", "Lantern",
];
pub const IMAGE_WIDTH: u32 = 700;
pub const HOUR_NAME_FONT_SIZE: f32 = IMAGE_WIDTH as f32 * 0.019109;
pub const OUTER_R: f32 = (IMAGE_WIDTH as f32) / 2.0 - 3.0 * HOUR_NAME_FONT_SIZE;
pub const RING_WIDTH: f32 = HOUR_NAME_FONT_SIZE * 3.0;
pub const UTC_HOUR_FONT_SIZE: f32 = IMAGE_WIDTH as f32 * 0.021462;

pub fn svg_to_usvg(document: Document) -> Tree {
    let doc_str = document.to_string();

    let mut opt = usvg::Options::default();
    opt.fontdb.load_system_fonts();
    opt.font_family = "Liberation Serif".to_string();

    Tree::from_str(&doc_str, &opt.to_ref()).unwrap()
}

fn hour_name_path() -> Path {
    let radius = OUTER_R - RING_WIDTH / 2.0;
    let delta_x = radius * (15.0_f32.to_radians() / 2.0).sin();
    let delta_y = radius * (1.0 - (15.0_f32.to_radians() / 2.0).cos());
    let x1 = (IMAGE_WIDTH as f32) / 2.0 - delta_x;
    let y1 = ((IMAGE_WIDTH as f32) / 2.0 - radius) + delta_y;

    let path_data = PathData::new().move_to((x1, y1)).elliptical_arc_by((
        radius,
        radius,
        15,
        0,
        1,
        2.0 * delta_x,
        0,
    ));

    Path::new().set("id", "hour-name-path").set("d", path_data)
}

fn create_temp_document(hour: usize) -> Document {
    let definitions = Definitions::new().add(hour_name_path());
    let utc_hour_y = IMAGE_WIDTH as f32 / 2.0 - OUTER_R + RING_WIDTH + UTC_HOUR_FONT_SIZE;

    let hour_name_text_path = TextPath::new()
        .set("xlink:href", "#hour-name-path")
        .set("startOffset", "50%")
        .add(TextNode::new(HOUR_NAMES[hour]));
    let hour_name_text = Text::new()
        .set("id", "hour-name")
        .set("text-anchor", "middle")
        .set("dominant-baseline", "mathematical")
        .set("font-size", HOUR_NAME_FONT_SIZE)
        .add(hour_name_text_path);
    let utc_hour_text = Text::new()
        .set("id", "utc-hour")
        .set(
            "transform",
            format!("rotate(-7.5, {}, {})", IMAGE_WIDTH / 2, IMAGE_WIDTH / 2),
        )
        .set("x", IMAGE_WIDTH / 2)
        .set("y", utc_hour_y)
        .set("text-anchor", "middle")
        .set("dominant-baseline", "mathematical")
        .set("font-size", UTC_HOUR_FONT_SIZE)
        .add(TextNode::new(format!("U {:02}", hour)));

    Document::new()
        .set("viewBox", (0i32, 0i32, 700i32, 700i32))
        .set("width", 700i32)
        .set("height", 700i32)
        .set("xmlns:xlink", "http://www.w3.org/1999/xlink")
        .add(definitions)
        .add(hour_name_text)
        .add(utc_hour_text)
}

fn node_to_path(node: Node<usvg::NodeKind>) -> PathData {
    let mut svg_path_data = PathData::new();

    match *node.borrow() {
        usvg::NodeKind::Path(ref path) => {
            let path_data = &path.data;
            for segment in path_data.0.iter() {
                match segment {
                    usvg::PathSegment::MoveTo { x, y } => {
                        svg_path_data = svg_path_data.move_to((*x, *y));
                    }
                    usvg::PathSegment::LineTo { x, y } => {
                        svg_path_data = svg_path_data.line_to((*x, *y));
                    }
                    usvg::PathSegment::CurveTo {
                        x1,
                        y1,
                        x2,
                        y2,
                        x,
                        y,
                    } => {
                        svg_path_data = svg_path_data.cubic_curve_to((*x1, *y1, *x2, *y2, *x, *y));
                    }
                    usvg::PathSegment::ClosePath => {
                        svg_path_data = svg_path_data.close();
                    }
                }
            }
        }
        _ => {
            unreachable!()
        }
    }

    svg_path_data
}

fn cache_hour_name_path(hour: usize) -> (PathData, PathData) {
    let tree = svg_to_usvg(create_temp_document(hour));
    let text_node = tree.node_by_id("hour-name").unwrap();
    let utc_text_node = tree.node_by_id("utc-hour").unwrap();
    (node_to_path(text_node), node_to_path(utc_text_node))
}

pub fn cache_hour_name_paths() -> [(PathData, PathData); 24] {
    [
        cache_hour_name_path(0),
        cache_hour_name_path(1),
        cache_hour_name_path(2),
        cache_hour_name_path(3),
        cache_hour_name_path(4),
        cache_hour_name_path(5),
        cache_hour_name_path(6),
        cache_hour_name_path(7),
        cache_hour_name_path(8),
        cache_hour_name_path(9),
        cache_hour_name_path(10),
        cache_hour_name_path(11),
        cache_hour_name_path(12),
        cache_hour_name_path(13),
        cache_hour_name_path(14),
        cache_hour_name_path(15),
        cache_hour_name_path(16),
        cache_hour_name_path(17),
        cache_hour_name_path(18),
        cache_hour_name_path(19),
        cache_hour_name_path(20),
        cache_hour_name_path(21),
        cache_hour_name_path(22),
        cache_hour_name_path(23),
    ]
}