use std::{env, path::Path};

use anyhow::{anyhow, bail};
use linuxvideo::Device;

fn usage() -> anyhow::Error {
    anyhow!("usage: control <device> <control> [<value>]")
}

fn main() -> anyhow::Result<()> {
    env_logger::init();

    let mut args = env::args_os().skip(1);

    let path = args.next().ok_or_else(usage)?;
    let control_name = args.next();
    let control_name = match control_name.as_ref() {
        Some(name) => Some(
            name.to_str()
                .ok_or_else(|| anyhow!("control name must be UTF-8"))?,
        ),
        None => None,
    };
    let value = args.next();
    let value = match value.as_ref() {
        Some(value) => Some(
            value
                .to_str()
                .ok_or_else(|| anyhow!("control name must be UTF-8"))?
                .parse()?,
        ),
        None => None,
    };

    let mut device = Device::open(Path::new(&path))?;

    let control_name = match control_name {
        Some(name) => name,
        None => {
            for desc in device.controls() {
                let desc = desc?;
                println!("{:?}", desc);
            }
            return Ok(());
        }
    };

    let mut cid = None;
    for desc in device.controls() {
        let desc = desc?;
        if desc.name().eq_ignore_ascii_case(control_name) {
            println!(
                "'{}' matches control {:?} [{}-{}, step {}, default {}]",
                control_name,
                desc.id(),
                desc.minimum(),
                desc.maximum(),
                desc.step(),
                desc.default_value(),
            );
            cid = Some(desc.id());
            break;
        }
    }

    match cid {
        Some(cid) => match value {
            Some(value) => {
                device.write_control_raw(cid, value)?;
            }
            None => {
                let value = device.read_control_raw(cid)?;
                println!("{:?} control value: {}", cid, value);
            }
        },
        None => bail!("device does not have control named {control_name}"),
    }

    Ok(())
}