//! UART driver

use self::config::Config;
#[cfg(uart2)]
use crate::peripherals::UART2;
use crate::{
    clock::Clocks,
    peripheral::{Peripheral, PeripheralRef},
    peripherals::{
        uart0::{fifo::FIFO_SPEC, RegisterBlock},
        UART0,
        UART1,
    },
    types::{InputSignal, OutputSignal},
    InputPin,
    OutputPin,
};

const UART_FIFO_SIZE: u16 = 128;

/// Custom serial error type
#[derive(Debug)]
pub enum Error {}

/// UART configuration
pub mod config {
    /// Number of data bits
    #[derive(PartialEq, Eq, Copy, Clone, Debug)]
    pub enum DataBits {
        DataBits5 = 0,
        DataBits6 = 1,
        DataBits7 = 2,
        DataBits8 = 3,
    }

    /// Parity check
    #[derive(PartialEq, Eq, Copy, Clone, Debug)]
    pub enum Parity {
        ParityNone,
        ParityEven,
        ParityOdd,
    }

    /// Number of stop bits
    #[derive(PartialEq, Eq, Copy, Clone, Debug)]
    pub enum StopBits {
        /// 1 stop bit
        STOP1   = 1,
        /// 1.5 stop bits
        STOP1P5 = 2,
        /// 2 stop bits
        STOP2   = 3,
    }

    /// UART configuration
    #[derive(Debug, Copy, Clone)]
    pub struct Config {
        pub baudrate: u32,
        pub data_bits: DataBits,
        pub parity: Parity,
        pub stop_bits: StopBits,
    }

    impl Config {
        pub fn baudrate(mut self, baudrate: u32) -> Self {
            self.baudrate = baudrate;
            self
        }

        pub fn parity_none(mut self) -> Self {
            self.parity = Parity::ParityNone;
            self
        }

        pub fn parity_even(mut self) -> Self {
            self.parity = Parity::ParityEven;
            self
        }

        pub fn parity_odd(mut self) -> Self {
            self.parity = Parity::ParityOdd;
            self
        }

        pub fn data_bits(mut self, data_bits: DataBits) -> Self {
            self.data_bits = data_bits;
            self
        }

        pub fn stop_bits(mut self, stop_bits: StopBits) -> Self {
            self.stop_bits = stop_bits;
            self
        }
    }

    impl Default for Config {
        fn default() -> Config {
            Config {
                baudrate: 115_200,
                data_bits: DataBits::DataBits8,
                parity: Parity::ParityNone,
                stop_bits: StopBits::STOP1,
            }
        }
    }

    /// Configuration for the AT-CMD detection functionality
    pub struct AtCmdConfig {
        pub pre_idle_count: Option<u16>,
        pub post_idle_count: Option<u16>,
        pub gap_timeout: Option<u16>,
        pub cmd_char: u8,
        pub char_num: Option<u8>,
    }

    impl AtCmdConfig {
        pub fn new(
            pre_idle_count: Option<u16>,
            post_idle_count: Option<u16>,
            gap_timeout: Option<u16>,
            cmd_char: u8,
            char_num: Option<u8>,
        ) -> AtCmdConfig {
            Self {
                pre_idle_count,
                post_idle_count,
                gap_timeout,
                cmd_char,
                char_num,
            }
        }
    }
}

/// Pins used by the UART interface
pub trait UartPins {
    fn configure_pins(
        &mut self,
        tx_signal: OutputSignal,
        rx_signal: InputSignal,
        cts_signal: InputSignal,
        rts_signal: OutputSignal,
    );
}

/// All pins offered by UART
pub struct AllPins<TX: OutputPin, RX: InputPin, CTS: InputPin, RTS: OutputPin> {
    pub tx: Option<TX>,
    pub rx: Option<RX>,
    pub cts: Option<CTS>,
    pub rts: Option<RTS>,
}

/// Tx and Rx pins
impl<TX: OutputPin, RX: InputPin, CTS: InputPin, RTS: OutputPin> AllPins<TX, RX, CTS, RTS> {
    pub fn new(tx: TX, rx: RX, cts: CTS, rts: RTS) -> AllPins<TX, RX, CTS, RTS> {
        AllPins {
            tx: Some(tx),
            rx: Some(rx),
            cts: Some(cts),
            rts: Some(rts),
        }
    }
}

impl<TX: OutputPin, RX: InputPin, CTS: InputPin, RTS: OutputPin> UartPins
    for AllPins<TX, RX, CTS, RTS>
{
    fn configure_pins(
        &mut self,
        tx_signal: OutputSignal,
        rx_signal: InputSignal,
        cts_signal: InputSignal,
        rts_signal: OutputSignal,
    ) {
        if let Some(ref mut tx) = self.tx {
            tx.set_to_push_pull_output()
                .connect_peripheral_to_output(tx_signal);
        }

        if let Some(ref mut rx) = self.rx {
            rx.set_to_input().connect_input_to_peripheral(rx_signal);
        }

        if let Some(ref mut cts) = self.cts {
            cts.set_to_input().connect_input_to_peripheral(cts_signal);
        }

        if let Some(ref mut rts) = self.rts {
            rts.set_to_push_pull_output()
                .connect_peripheral_to_output(rts_signal);
        }
    }
}

pub struct TxRxPins<TX: OutputPin, RX: InputPin> {
    pub tx: Option<TX>,
    pub rx: Option<RX>,
}

impl<TX: OutputPin, RX: InputPin> TxRxPins<TX, RX> {
    pub fn new_tx_rx(tx: TX, rx: RX) -> TxRxPins<TX, RX> {
        TxRxPins {
            tx: Some(tx),
            rx: Some(rx),
        }
    }
}

impl<TX: OutputPin, RX: InputPin> UartPins for TxRxPins<TX, RX> {
    fn configure_pins(
        &mut self,
        tx_signal: OutputSignal,
        rx_signal: InputSignal,
        _cts_signal: InputSignal,
        _rts_signal: OutputSignal,
    ) {
        if let Some(ref mut tx) = self.tx {
            tx.set_to_push_pull_output()
                .connect_peripheral_to_output(tx_signal);
        }

        if let Some(ref mut rx) = self.rx {
            rx.set_to_input().connect_input_to_peripheral(rx_signal);
        }
    }
}

#[cfg(feature = "eh1")]
impl embedded_hal_1::serial::Error for Error {
    fn kind(&self) -> embedded_hal_1::serial::ErrorKind {
        embedded_hal_1::serial::ErrorKind::Other
    }
}

/// UART driver
pub struct Uart<'d, T> {
    uart: PeripheralRef<'d, T>,
}

impl<'d, T> Uart<'d, T>
where
    T: Instance,
{
    /// Create a new UART instance with defaults
    pub fn new_with_config<P>(
        uart: impl Peripheral<P = T> + 'd,
        config: Option<Config>,
        mut pins: Option<P>,
        clocks: &Clocks,
    ) -> Self
    where
        P: UartPins,
    {
        crate::into_ref!(uart);
        let mut serial = Uart { uart };
        serial.uart.disable_rx_interrupts();
        serial.uart.disable_tx_interrupts();

        if let Some(ref mut pins) = pins {
            pins.configure_pins(
                serial.uart.tx_signal(),
                serial.uart.rx_signal(),
                serial.uart.cts_signal(),
                serial.uart.rts_signal(),
            );
        }

        config.map(|config| {
            serial.change_data_bits(config.data_bits);
            serial.change_parity(config.parity);
            serial.change_stop_bits(config.stop_bits);
            serial.change_baud(config.baudrate, clocks);
        });

        serial
    }

    /// Create a new UART instance with defaults
    pub fn new(uart: impl Peripheral<P = T> + 'd) -> Self {
        crate::into_ref!(uart);
        let mut serial = Uart { uart };
        serial.uart.disable_rx_interrupts();
        serial.uart.disable_tx_interrupts();

        serial
    }

    /// Writes bytes
    pub fn write_bytes(&mut self, data: &[u8]) -> Result<(), Error> {
        data.iter()
            .try_for_each(|c| nb::block!(self.write_byte(*c)))
    }

    /// Configures the AT-CMD detection settings.
    pub fn set_at_cmd(&mut self, config: config::AtCmdConfig) {
        #[cfg(not(any(esp32, esp32s2)))]
        self.uart
            .register_block()
            .clk_conf
            .modify(|_, w| w.sclk_en().clear_bit());

        self.uart.register_block().at_cmd_char.write(|w| unsafe {
            w.at_cmd_char()
                .bits(config.cmd_char)
                .char_num()
                .bits(config.char_num.or(Some(1)).unwrap())
        });

        if let Some(pre_idle_count) = config.pre_idle_count {
            self.uart
                .register_block()
                .at_cmd_precnt
                .write(|w| unsafe { w.pre_idle_num().bits(pre_idle_count.into()) });
        }

        if let Some(post_idle_count) = config.post_idle_count {
            self.uart
                .register_block()
                .at_cmd_postcnt
                .write(|w| unsafe { w.post_idle_num().bits(post_idle_count.into()) });
        }

        if let Some(gap_timeout) = config.gap_timeout {
            self.uart
                .register_block()
                .at_cmd_gaptout
                .write(|w| unsafe { w.rx_gap_tout().bits(gap_timeout.into()) });
        }

        #[cfg(not(any(esp32, esp32s2)))]
        self.uart
            .register_block()
            .clk_conf
            .modify(|_, w| w.sclk_en().set_bit());
    }

    /// Configures the RX-FIFO threshold
    pub fn set_rx_fifo_full_threshold(&mut self, threshold: u16) {
        #[cfg(esp32)]
        let threshold: u8 = threshold as u8;

        self.uart
            .register_block()
            .conf1
            .modify(|_, w| unsafe { w.rxfifo_full_thrhd().bits(threshold) });
    }

    /// Listen for AT-CMD interrupts
    pub fn listen_at_cmd(&mut self) {
        self.uart
            .register_block()
            .int_ena
            .modify(|_, w| w.at_cmd_char_det_int_ena().set_bit());
    }

    /// Stop listening for AT-CMD interrupts
    pub fn unlisten_at_cmd(&mut self) {
        self.uart
            .register_block()
            .int_ena
            .modify(|_, w| w.at_cmd_char_det_int_ena().clear_bit());
    }

    /// Listen for TX-DONE interrupts
    pub fn listen_tx_done(&mut self) {
        self.uart
            .register_block()
            .int_ena
            .modify(|_, w| w.tx_done_int_ena().set_bit());
    }

    /// Stop listening for TX-DONE interrupts
    pub fn unlisten_tx_done(&mut self) {
        self.uart
            .register_block()
            .int_ena
            .modify(|_, w| w.tx_done_int_ena().clear_bit());
    }

    /// Listen for RX-FIFO-FULL interrupts
    pub fn listen_rx_fifo_full(&mut self) {
        self.uart
            .register_block()
            .int_ena
            .modify(|_, w| w.rxfifo_full_int_ena().set_bit());
    }

    /// Stop listening for RX-FIFO-FULL interrupts
    pub fn unlisten_rx_fifo_full(&mut self) {
        self.uart
            .register_block()
            .int_ena
            .modify(|_, w| w.rxfifo_full_int_ena().clear_bit());
    }

    /// Checks if AT-CMD interrupt is set
    pub fn at_cmd_interrupt_set(&self) -> bool {
        self.uart
            .register_block()
            .int_raw
            .read()
            .at_cmd_char_det_int_raw()
            .bit_is_set()
    }

    /// Checks if TX-DONE interrupt is set
    pub fn tx_done_interrupt_set(&self) -> bool {
        self.uart
            .register_block()
            .int_raw
            .read()
            .tx_done_int_raw()
            .bit_is_set()
    }

    /// Checks if RX-FIFO-FULL interrupt is set
    pub fn rx_fifo_full_interrupt_set(&self) -> bool {
        self.uart
            .register_block()
            .int_raw
            .read()
            .rxfifo_full_int_raw()
            .bit_is_set()
    }

    /// Reset AT-CMD interrupt
    pub fn reset_at_cmd_interrupt(&self) {
        self.uart
            .register_block()
            .int_clr
            .write(|w| w.at_cmd_char_det_int_clr().set_bit());
    }

    /// Reset TX-DONE interrupt
    pub fn reset_tx_done_interrupt(&self) {
        self.uart
            .register_block()
            .int_clr
            .write(|w| w.tx_done_int_clr().set_bit());
    }

    /// Reset RX-FIFO-FULL interrupt
    pub fn reset_rx_fifo_full_interrupt(&self) {
        self.uart
            .register_block()
            .int_clr
            .write(|w| w.rxfifo_full_int_clr().set_bit());
    }

    fn write_byte(&mut self, word: u8) -> nb::Result<(), Error> {
        if self.uart.get_tx_fifo_count() < UART_FIFO_SIZE {
            self.uart
                .register_block()
                .fifo
                .write(|w| unsafe { w.rxfifo_rd_byte().bits(word) });

            Ok(())
        } else {
            Err(nb::Error::WouldBlock)
        }
    }

    fn flush_tx(&self) -> nb::Result<(), Error> {
        if self.uart.is_tx_idle() {
            Ok(())
        } else {
            Err(nb::Error::WouldBlock)
        }
    }

    fn read_byte(&mut self) -> nb::Result<u8, Error> {
        #[allow(unused_variables)]
        let offset = 0;

        // on ESP32-S2 we need to use PeriBus2 to read the FIFO
        #[cfg(esp32s2)]
        let offset = 0x20c00000;

        if self.uart.get_rx_fifo_count() > 0 {
            let value = unsafe {
                let fifo = (self.uart.register_block().fifo.as_ptr() as *mut u8).offset(offset)
                    as *mut crate::peripherals::generic::Reg<FIFO_SPEC>;
                (*fifo).read().rxfifo_rd_byte().bits()
            };

            Ok(value)
        } else {
            Err(nb::Error::WouldBlock)
        }
    }

    /// Change the number of stop bits
    pub fn change_stop_bits(&mut self, stop_bits: config::StopBits) -> &mut Self {
        // workaround for hardware issue, when UART stop bit set as 2-bit mode.
        #[cfg(esp32)]
        if stop_bits == config::StopBits::STOP2 {
            self.uart
                .register_block()
                .rs485_conf
                .modify(|_, w| w.dl1_en().bit(true));

            self.uart
                .register_block()
                .conf0
                .modify(|_, w| unsafe { w.stop_bit_num().bits(1) });
        } else {
            self.uart
                .register_block()
                .rs485_conf
                .modify(|_, w| w.dl1_en().bit(false));

            self.uart
                .register_block()
                .conf0
                .modify(|_, w| unsafe { w.stop_bit_num().bits(stop_bits as u8) });
        }

        #[cfg(not(esp32))]
        self.uart
            .register_block()
            .conf0
            .modify(|_, w| unsafe { w.stop_bit_num().bits(stop_bits as u8) });

        self
    }

    /// Change the number of data bits
    fn change_data_bits(&mut self, data_bits: config::DataBits) -> &mut Self {
        self.uart
            .register_block()
            .conf0
            .modify(|_, w| unsafe { w.bit_num().bits(data_bits as u8) });

        self
    }

    /// Change the type of parity checking
    fn change_parity(&mut self, parity: config::Parity) -> &mut Self {
        self.uart
            .register_block()
            .conf0
            .modify(|_, w| match parity {
                config::Parity::ParityNone => w.parity_en().clear_bit(),
                config::Parity::ParityEven => w.parity_en().set_bit().parity().clear_bit(),
                config::Parity::ParityOdd => w.parity_en().set_bit().parity().set_bit(),
            });

        self
    }

    #[cfg(any(esp32c2, esp32c3, esp32s3))]
    fn change_baud(&self, baudrate: u32, clocks: &Clocks) {
        // we force the clock source to be APB and don't use the decimal part of the
        // divider
        let clk = clocks.apb_clock.to_Hz();
        let max_div = 0b1111_1111_1111 - 1;
        let clk_div = ((clk) + (max_div * baudrate) - 1) / (max_div * baudrate);

        self.uart.register_block().clk_conf.write(|w| unsafe {
            w.sclk_sel()
                .bits(1) // APB
                .sclk_div_a()
                .bits(0)
                .sclk_div_b()
                .bits(0)
                .sclk_div_num()
                .bits(clk_div as u8 - 1)
                .rx_sclk_en()
                .bit(true)
                .tx_sclk_en()
                .bit(true)
        });

        let clk = clk / clk_div;
        let divider = clk / baudrate;
        let divider = divider as u16;

        self.uart
            .register_block()
            .clkdiv
            .write(|w| unsafe { w.clkdiv().bits(divider).frag().bits(0) });
    }

    #[cfg(any(esp32, esp32s2))]
    fn change_baud(&self, baudrate: u32, clocks: &Clocks) {
        // we force the clock source to be APB and don't use the decimal part of the
        // divider
        let clk = clocks.apb_clock.to_Hz();

        self.uart
            .register_block()
            .conf0
            .modify(|_, w| w.tick_ref_always_on().bit(true));
        let divider = clk / baudrate;

        self.uart
            .register_block()
            .clkdiv
            .write(|w| unsafe { w.clkdiv().bits(divider).frag().bits(0) });
    }
}

/// UART peripheral instance
pub trait Instance {
    fn register_block(&self) -> &RegisterBlock;

    fn disable_tx_interrupts(&mut self) {
        self.register_block().int_clr.write(|w| {
            w.txfifo_empty_int_clr()
                .set_bit()
                .tx_brk_done_int_clr()
                .set_bit()
                .tx_brk_idle_done_int_clr()
                .set_bit()
                .tx_done_int_clr()
                .set_bit()
        });

        self.register_block().int_ena.write(|w| {
            w.txfifo_empty_int_ena()
                .clear_bit()
                .tx_brk_done_int_ena()
                .clear_bit()
                .tx_brk_idle_done_int_ena()
                .clear_bit()
                .tx_done_int_ena()
                .clear_bit()
        });
    }

    fn disable_rx_interrupts(&mut self) {
        self.register_block().int_clr.write(|w| {
            w.rxfifo_full_int_clr()
                .set_bit()
                .rxfifo_ovf_int_clr()
                .set_bit()
                .rxfifo_tout_int_clr()
                .set_bit()
        });

        self.register_block().int_ena.write(|w| {
            w.rxfifo_full_int_ena()
                .clear_bit()
                .rxfifo_ovf_int_ena()
                .clear_bit()
                .rxfifo_tout_int_ena()
                .clear_bit()
        });
    }

    fn get_tx_fifo_count(&mut self) -> u16 {
        self.register_block()
            .status
            .read()
            .txfifo_cnt()
            .bits()
            .into()
    }

    fn get_rx_fifo_count(&mut self) -> u16 {
        self.register_block()
            .status
            .read()
            .rxfifo_cnt()
            .bits()
            .into()
    }

    fn is_tx_idle(&self) -> bool {
        #[cfg(esp32)]
        let idle = self.register_block().status.read().st_utx_out().bits() == 0x0u8;
        #[cfg(not(esp32))]
        let idle = self.register_block().fsm_status.read().st_utx_out().bits() == 0x0u8;

        idle
    }

    fn is_rx_idle(&self) -> bool {
        #[cfg(esp32)]
        let idle = self.register_block().status.read().st_urx_out().bits() == 0x0u8;
        #[cfg(not(esp32))]
        let idle = self.register_block().fsm_status.read().st_urx_out().bits() == 0x0u8;

        idle
    }

    fn tx_signal(&self) -> OutputSignal;

    fn rx_signal(&self) -> InputSignal;

    fn cts_signal(&self) -> InputSignal;

    fn rts_signal(&self) -> OutputSignal;
}

impl Instance for UART0 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    fn tx_signal(&self) -> OutputSignal {
        OutputSignal::U0TXD
    }

    fn rx_signal(&self) -> InputSignal {
        InputSignal::U0RXD
    }

    fn cts_signal(&self) -> InputSignal {
        InputSignal::U0CTS
    }

    fn rts_signal(&self) -> OutputSignal {
        OutputSignal::U0RTS
    }
}

impl Instance for UART1 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    fn tx_signal(&self) -> OutputSignal {
        OutputSignal::U1TXD
    }

    fn rx_signal(&self) -> InputSignal {
        InputSignal::U1RXD
    }

    fn cts_signal(&self) -> InputSignal {
        InputSignal::U1CTS
    }

    fn rts_signal(&self) -> OutputSignal {
        OutputSignal::U1RTS
    }
}

#[cfg(uart2)]
impl Instance for UART2 {
    #[inline(always)]
    fn register_block(&self) -> &RegisterBlock {
        self
    }

    fn tx_signal(&self) -> OutputSignal {
        OutputSignal::U2TXD
    }

    fn rx_signal(&self) -> InputSignal {
        InputSignal::U2RXD
    }

    fn cts_signal(&self) -> InputSignal {
        InputSignal::U2CTS
    }

    fn rts_signal(&self) -> OutputSignal {
        OutputSignal::U2RTS
    }
}

#[cfg(feature = "ufmt")]
impl<T> ufmt_write::uWrite for Uart<'_, T>
where
    T: Instance,
{
    type Error = Error;

    #[inline]
    fn write_str(&mut self, s: &str) -> Result<(), Self::Error> {
        self.write_bytes(s.as_bytes())
    }

    #[inline]
    fn write_char(&mut self, ch: char) -> Result<(), Self::Error> {
        let mut buffer = [0u8; 4];
        self.write_bytes(ch.encode_utf8(&mut buffer).as_bytes())
    }
}

impl<T> core::fmt::Write for Uart<'_, T>
where
    T: Instance,
{
    #[inline]
    fn write_str(&mut self, s: &str) -> core::fmt::Result {
        self.write_bytes(s.as_bytes()).map_err(|_| core::fmt::Error)
    }
}

impl<T> embedded_hal::serial::Write<u8> for Uart<'_, T>
where
    T: Instance,
{
    type Error = Error;

    fn write(&mut self, word: u8) -> nb::Result<(), Self::Error> {
        self.write_byte(word)
    }

    fn flush(&mut self) -> nb::Result<(), Self::Error> {
        self.flush_tx()
    }
}

impl<T> embedded_hal::serial::Read<u8> for Uart<'_, T>
where
    T: Instance,
{
    type Error = Error;

    fn read(&mut self) -> nb::Result<u8, Self::Error> {
        self.read_byte()
    }
}

#[cfg(feature = "eh1")]
impl<T> embedded_hal_1::serial::ErrorType for Uart<'_, T> {
    type Error = Error;
}

#[cfg(feature = "eh1")]
impl<T> embedded_hal_nb::serial::Read for Uart<'_, T>
where
    T: Instance,
{
    fn read(&mut self) -> nb::Result<u8, Self::Error> {
        self.read_byte()
    }
}

#[cfg(feature = "eh1")]
impl<T> embedded_hal_nb::serial::Write for Uart<'_, T>
where
    T: Instance,
{
    fn write(&mut self, word: u8) -> nb::Result<(), Self::Error> {
        self.write_byte(word)
    }

    fn flush(&mut self) -> nb::Result<(), Self::Error> {
        self.flush_tx()
    }
}