use libboard_zynq;

pub static mut I2C_BUS: Option<libboard_zynq::i2c::I2c> = None;

pub fn start() -> Result<(), &'static str> {
    unsafe {
        if (&mut I2C_BUS).as_mut().unwrap().start().is_err() {
            Err("I2C start failed")
        } else {
            Ok(())
        }
    }
}

pub fn restart() -> Result<(), &'static str> {
    unsafe {
        if (&mut I2C_BUS).as_mut().unwrap().restart().is_err() {
            Err("I2C restart failed")
        } else {
            Ok(())
        }
    }
}

pub fn stop() -> Result<(), &'static str> {
    unsafe {
        if (&mut I2C_BUS).as_mut().unwrap().stop().is_err() {
            Err("I2C stop failed")
        } else {
            Ok(())
        }
    }
}

pub fn write(data: i32) -> Result<bool, &'static str> {
    unsafe {
        match (&mut I2C_BUS).as_mut().unwrap().write(data as u8) {
            Ok(r) =>Ok(r),
            Err(_) => Err("I2C write failed"),
        }
    }
}

pub fn read(ack: bool) -> Result<i32, &'static str> {
    unsafe {
        match (&mut I2C_BUS).as_mut().unwrap().read(ack) {
            Ok(r) => Ok(r as i32),
            Err(_) => Err("I2C read failed"),
        }
    }
}

pub fn pca954x_select(address: i32, channel: Option<u8>) -> Result<(), &'static str> {
    unsafe {
        if (&mut I2C_BUS).as_mut().unwrap().pca954x_select(address as u8, channel).is_err() {
            Err("switch select failed")
        } else {
            Ok(())
        }
    }
}

pub fn switch_select(address: i32, mask: i32) -> Result<(), &'static str> {
    let ch = match mask { //decode from mainline, PCA9548-centric API
        0x00 => None,
        0x01 => Some(0),
        0x02 => Some(1),
        0x04 => Some(2),
        0x08 => Some(3),
        0x10 => Some(4),
        0x20 => Some(5),
        0x40 => Some(6),
        0x80 => Some(7),
        _ => return Err("switch select supports only one channel")
    };
    pca954x_select(address, ch)
}

pub fn init() {
    let mut i2c = libboard_zynq::i2c::I2c::i2c0();
    i2c.init().expect("I2C bus initialization failed");
    unsafe { I2C_BUS = Some(i2c) };
}