billiards/build.rs

use std::env;
use std::fs;
use std::path::Path;
use std::iter::once;

fn main() {
	let out_dir = env::var_os("OUT_DIR").unwrap();
	let dest_path = Path::new(&out_dir).join("builtin_tables.rs");

	let configs = rusqlite::Connection::open("tables.db")
		.unwrap()
		.prepare("SELECT * FROM tables")
		.unwrap()
		.query_map([], |row| Ok((
			row.get::<_, String>("name")?,
			row.get::<_, String>("outline")?,
			row.get::<_, f64>("pos_x")?,
			row.get::<_, f64>("pos_y")?,
			row.get::<_, f64>("vec_x")?,
			row.get::<_, f64>("vec_y")?,
		)))
		.unwrap()
		.collect::<Result<Vec<_>, _>>()
		.unwrap();

	let mut lines: Vec<String> = Vec::new();
	for (name, outline, pos_x, pos_y, vec_x, vec_y) in &configs {
		let outline_parsed: Vec<(f64, f64)> =
			serde_json::from_str(outline)
			.expect("outline field should be a valid [(f64, f64)]");

		let outline_str: String = outline_parsed
			.into_iter()
			.map(|x|format!("({:.15},{:.15}),",x.0,x.1))
			.collect();

		lines.push(format!(
			"BilliardConfiguration {{ name: {:?}.into(), outline: vec![{}], initial_pos: ({:.15}, {:.15}), initial_vec: ({:.15}, {:.15}) }},\n",
			name, &outline_str, *pos_x, *pos_y, *vec_x, *vec_y
		));
	}

	fs::write(
		&dest_path,
		once("vec![")
			.chain(lines.iter()
				   .map(String::as_str)
				   .chain(once("]")))
			.collect::<String>()
	).unwrap();

	println!("cargo::rerun-if-changed=build.rs");
}