/*
    Hurry Curry! - a game about cooking
    Copyright (C) 2025 Hurry Curry! Contributors

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, version 3 of the License only.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.

*/

use anyhow::Result;
use hurrycurry_protocol::{
    Gamedata, Message,
    book::{Diagram, DiagramEdge, DiagramNode, EdgeStyle, NodeStyle},
    glam::Vec2,
};
use std::fmt::Write;

const SIZE: f32 = 64.;
const HSIZE: f32 = SIZE / 2.;

pub fn diagram_svg(data: &Gamedata, diagram: &Diagram) -> Result<String> {
    let mut out = String::new();

    let (vb_min, vb_max) = diagram
        .nodes
        .iter()
        .map(|n| (n.position, n.position))
        .reduce(|(xa, xb), (ya, yb)| (xa.min(ya), xb.max(yb)))
        .unwrap();

    writeln!(
        out,
        r#"<svg xmlns="http://www.w3.org/2000/svg" viewBox="{} {} {} {}" width="{}" height="{}">"#,
        vb_min.x - HSIZE,
        vb_min.y - HSIZE,
        vb_max.x + HSIZE,
        vb_max.y + HSIZE,
        vb_max.x - vb_min.x + SIZE,
        vb_max.y - vb_min.y + SIZE,
    )?;

    for node in &diagram.nodes {
        match node.label {
            Message::Translation { .. } => {}
            Message::Text(_) => {}
            Message::Item(item_index) => {
                image_node(
                    &mut out,
                    node,
                    format!("items/{}.png", data.item_name(item_index)),
                )?;
            }
            Message::Tile(tile_index) => {
                image_node(
                    &mut out,
                    node,
                    format!("tiles/{}.png", data.tile_name(tile_index)),
                )?;
            }
        }
    }
    for edge in &diagram.edges {
        let src_node = &diagram.nodes[edge.src];
        let dst_node = &diagram.nodes[edge.dst];
        let src = node_edge_connect_pos(src_node, dst_node);
        let mut dst = node_edge_connect_pos(dst_node, src_node);

        let dir = (src - dst).normalize_or_zero();
        let tip0 = dst;
        let tip1 = dst + (dir + dir.perp() * 0.5) * 10.;
        let tip2 = dst + (dir + dir.perp() * -0.5) * 10.;
        dst += dir * 5.; // prevent miter line cap from peeking out

        let color = edge_color(edge);

        // line path
        writeln!(
            out,
            r#"<path fill="none" stroke="{color}" stroke-width="2" d="M{} {} L{} {}" />"#,
            src.x, src.y, dst.x, dst.y,
        )?;
        // tip path
        writeln!(
            out,
            r#"<path fill="{color}" stroke="none" d="M{} {} L{} {} L{} {} Z" />"#,
            tip0.x, tip0.y, tip1.x, tip1.y, tip2.x, tip2.y
        )?;
    }

    writeln!(out, "</svg>")?;
    Ok(out)
}

fn node_edge_connect_pos(src: &DiagramNode, dst: &DiagramNode) -> Vec2 {
    let dir = (dst.position - src.position).normalize_or_zero();
    if matches!(
        src.style,
        NodeStyle::FinalProduct | NodeStyle::IntermediateProduct
    ) {
        src.position + dir * HSIZE // circle
    } else {
        src.position + dir / dir.y.abs() * HSIZE // square (only +Y and -Y sides)
    }
}

pub(crate) fn node_color(node: &DiagramNode) -> &'static str {
    match node.style {
        NodeStyle::FinalProduct => "#555",
        NodeStyle::IntermediateProduct => "#333",
        NodeStyle::ProcessActive => "#47c42b",
        NodeStyle::ProcessPassive => "#c4a32b",
        NodeStyle::ProcessInstant => "#5452d8",
    }
}
pub(crate) fn edge_color(edge: &DiagramEdge) -> &'static str {
    match edge.style {
        EdgeStyle::Regular => "#000000",
        EdgeStyle::ProcessPassive => "#c4a32b",
    }
}

fn image_node(out: &mut String, node: &DiagramNode, path: String) -> Result<()> {
    if matches!(
        node.style,
        NodeStyle::FinalProduct | NodeStyle::IntermediateProduct
    ) {
        writeln!(
            out,
            r#"<circle cx="{}" cy="{}" r="{}" stroke="none" fill="{}" />"#,
            node.position.x,
            node.position.y,
            HSIZE,
            node_color(node)
        )?;
    } else {
        writeln!(
            out,
            r#"<rect x="{}" y="{}" width="{SIZE}" height="{SIZE}" stroke="none" fill="{}" />"#,
            node.position.x - HSIZE,
            node.position.y - HSIZE,
            node_color(node)
        )?;
    }
    writeln!(
        out,
        r#"<image href="{path}" x="{}" y="{}" width="{SIZE}" height="{SIZE}" />"#,
        node.position.x - HSIZE,
        node.position.y - HSIZE,
    )?;
    Ok(())
}