use field_offset::offset_of;
use stm32l4xx_hal::prelude::_embedded_hal_blocking_i2c_Write;
use tock_registers::{
    interfaces::{ReadWriteable, Readable},
    register_bitfields, register_structs,
    registers::InMemoryRegister,
};

const TUSB322_ADDR: u8 = 0x47;

register_bitfields![
    u8,
    // Connection status register
    ConnStatus1 [
        // Indicates that active cable has been plugged in
        ACTIVE_CABLE_DETECTION OFFSET(0) NUMBITS(1) [],
        // Read by the application to determine if accessory was attached
        ACCESSORY_CONNECTED OFFSET(1) NUMBITS(3) [
            None = 0,
            Audio = 4,
            AudioCharged = 5,
            DebugDfp = 6,
            DebugUfp = 7,
        ],
        // Set in UFP mode with the detected current mode
        CURRENT_MODE_DETECT OFFSET(4) NUMBITS(2) [
            Default = 0,
            Medium = 1,
            ChargeThrough = 2,
            High = 3,
        ],
        // Programmed by application to change current advertisement
        CURRENT_MODE_ADVERTISE OFFSET(6) NUMBITS(2) [
            Default = 0,
            Mid = 1,
            High = 2,
            Reserved = 3,
        ],
    ],
    // Connection status and control register
    ConnStatus2 [
        // Setting this field will disable UFP accessory support
        DISABLE_UFP_ACCESSORY OFFSET(0) NUMBITS(1) [],
        // Percentage of time that a DRP advertised DFP during tDRP
        DRP_DUTY_CYCLE OFFSET(1) NUMBITS(2) [
            p30 = 0,
            p40 = 1,
            p50 = 2,
            p60 = 3,
        ],
        // Set when over-current limit is triggered
        VCONN_FAULT OFFSET(3) NUMBITS(1) [],
        // Pulled low when a control or status register changes
        INTERRUPT_STATUS OFFSET(4) NUMBITS(1) [
            Clear = 0,
            Changed = 1,
        ],
        // Cable orientation
        CABLE_DIR OFFSET(5) NUMBITS(1) [
            CC1 = 0,
            CC2 = 1,
        ],
        // Attached state (same as ID pin)
        ATTACHED_STATE OFFSET(6) NUMBITS(2) [
            NotAttached = 0,
            AttachedSrc_DFP = 1,
            AttachedSnk_UFP = 2,
            AttachedAccessory = 3,
        ],
    ],
    // General control register
    Control [
        // Disable CC pin termination
        DISABLE_TERM OFFSET(0) NUMBITS(1) [],
        // Control behavior when configured as DRP
        SOURCE_PERF OFFSET(1) NUMBITS(2) [
            StandardDrp = 0,
            DrpTrySnk = 1,
            Reserved = 2,
            DrpTrySrc = 3,
        ],
        // Soft reset internal logic (self-clearing)
        I2C_SOFT_RESET OFFSET(3) NUMBITS(1) [],
        // Configure device operation mode
        MODE_SELECT OFFSET(4) NUMBITS(2) [
            Drp = 0,
            Ufp = 1,
            Dfp = 2,
        ],
        // Debounce time on CC pins
        DEBOUNCE OFFSET(6) NUMBITS(2) [
            ms168 = 0,
            ms118 = 1,
            ms134 = 2,
            ms152 = 3,
        ],
    ],
];

register_structs! {
    Tusb322Registers {
        (0x00 => id:    [u8; 8]),
        (0x08 => stat1: InMemoryRegister<u8, ConnStatus1::Register>),
        (0x09 => stat2: InMemoryRegister<u8, ConnStatus2::Register>),
        (0x0A => ctrl:  InMemoryRegister<u8, Control::Register>),
        (0x0B => @END),
    }
}

impl Tusb322Registers {
    const fn default() -> Self {
        Self {
            id: [0; 8],
            stat1: InMemoryRegister::new(0x00),
            stat2: InMemoryRegister::new(0x00),
            ctrl: InMemoryRegister::new(0x00),
        }
    }
    // Program control registers
    fn i2c_write_regs(&self, address: u8, i2c: &mut impl _embedded_hal_blocking_i2c_Write) {
        let mut buffer: [u8; 4] = [0; 4];
        buffer[0] = offset_of!(Tusb322Registers => stat1).get_byte_offset() as u8;
        buffer[1] = self.stat1.get();
        buffer[2] = self.stat2.get();
        buffer[3] = self.ctrl.get();

        match i2c.write(address, &buffer) {
            Ok(_) => (),
            Err(_) => panic!(),
        }
    }
}

pub fn init(i2c: &mut impl _embedded_hal_blocking_i2c_Write) {
    let reg: Tusb322Registers = Tusb322Registers::default();

    // Disable UFP accessory support (otherwise IC stays in DRP mode)
    reg.stat2.modify(ConnStatus2::DISABLE_UFP_ACCESSORY::SET);

    // Disable CC termination to change to UFP mode
    reg.ctrl.modify(Control::DISABLE_TERM::SET);

    // For operation in UFP mode
    reg.ctrl.modify(Control::MODE_SELECT::Ufp);

    reg.i2c_write_regs(TUSB322_ADDR, i2c);

    // Re-enable CC termination
    reg.ctrl.modify(Control::DISABLE_TERM::CLEAR);

    reg.i2c_write_regs(TUSB322_ADDR, i2c);
}