/*****************************************************************************
 * Module: DasKeyboard
 * Created On: Fri 07 May 2021 10:17:24 PM CEST
 * Last Modified: Sat 08 May 2021 10:14:52 PM CEST
 *
 * Driver for DasKeyboard keyboards light
 * Jali <jali@orca-central.de>
 *****************************************************************************/

use hidapi::{DeviceInfo, HidApi, HidError, HidResult};
use std::ffi::{CStr, CString};
use Usb::UsbDevice;

/** Driver for DasKeyboard RGB keyboards
 *  lighting controller
 */
pub struct DasKeyboardController {
    _dev: UsbDevice,
    _location: CString,
    _use_traditional_send_data: bool,
    _version: String,
}

/** Implementation of the controller. */
impl DasKeyboardController {
    /**
     * Creates a new instance of ```DasKeyboardController```, which is
     * bound to a currently connected device.
     *
     * # Arguments
     *
     * * `vendor_id` - The unique vendor/manufactorer id of the device
     * * `product_id` - The unique product id of the device.
     */
    pub fn new(vendor_id: u16, product_id: u16) -> HidResult<DasKeyboardController> {}

    /** Send a command to the HID controller in the traditional way,
     * sending 8 bytes per call.
     *
     * # Arguments
     *
     * * `api` - Reference to the HidApi object.
     * * `device_info` - Reference to the device to write to.
     */
    fn send_data_traditional(usb_device: &UsbDevice, data: &[u8]) {
        // traditional send_data (split into chunks of 8 bytes)
        let mut usb_buf = [0u8; 9];
        let err_cnt = 3;
        let chk_sum = 0;
        
        usb_device.open().and_then(|dev| {
            for idx in (1..data.len() + 1).step_by(7) {
                usb_buf[0] = 1;
                for fld_idx in (1..7) {
                    let tmp_idx = idx + fld_idx -1;
                    if tmp_idx < length {
                        usb_buf[fld_idx] = data[tmp_idx];
                        chk_sum ^= data[tmp_idx];
                    }
                    else if tmp_idx == data.len() {
                        usb_buf[fld_idx] = chk_sum;
                    }
                    else {
                        usb_buf[fld_idx] = 0
                    }
                }
                match dev.send_feature_report(usb_buf) {
                    Ok(_) {
                        ()
                    },
                    Err(_) {
                        idx = 0;
                        if err_cnt == 0 {
                            return ();
                        }
                        err_cnt -= 1;
                        ()
                    }
                }
            } 
        })
    }
}