#![no_std]

extern crate embedded_hal as hal;

use hal::blocking::spi;
use hal::blocking::delay::DelayMs;
use hal::spi::{Mode, Phase, Polarity};
use hal::digital::OutputPin;

use core::iter::IntoIterator;

/// SPI mode
pub const MODE: Mode = Mode {
    polarity: Polarity::IdleLow,
    phase: Phase::CaptureOnFirstTransition,
};

pub const WIDTH: u16 = 240;
pub const HEIGHT: u16 = 320;

#[derive(Debug)]
pub enum Error<E> {
    Spi(E),
}

pub struct Ili9341<SPI, CS, DC, RESET> {
    spi: SPI,
    cs: CS,
    dc: DC,
    reset: RESET,
    width: usize,
    height: usize,
}

impl<E, SPI, CS, DC, RESET> Ili9341<SPI, CS, DC, RESET>
where
    SPI: spi::Transfer<u8, Error = E> + spi::Write<u8, Error = E>,
    CS: OutputPin,
    DC: OutputPin,
    RESET: OutputPin, 
{
    pub fn new<DELAY: DelayMs<u16>>(spi: SPI, cs: CS, dc: DC, reset: RESET, delay: &mut DELAY) -> Result<Self, Error<E>> {
        let mut ili9341 = Ili9341 {
            spi,
            cs,
            dc,
            reset,
            width: 240,
            height: 320,
        };

        ili9341.hard_reset(delay);
        ili9341.command(Command::SoftwareReset, &[])?;
        delay.delay_ms(200);

        ili9341.command(Command::PowerControlA, &[0x39, 0x2c, 0x00, 0x34, 0x02])?;
        ili9341.command(Command::PowerControlB, &[0x00, 0xc1, 0x30])?;
        ili9341.command(Command::DriverTimingControlA, &[0x85, 0x00, 0x78])?;
        ili9341.command(Command::DriverTimingControlB, &[0x00, 0x00])?;
        ili9341.command(Command::PowerOnSequenceControl, &[0x64, 0x03, 0x12, 0x81])?;
        ili9341.command(Command::PumpRatioControl, &[0x20])?;
        ili9341.command(Command::PowerControl1, &[0x23])?;
        ili9341.command(Command::PowerControl2, &[0x10])?;
        ili9341.command(Command::VCOMControl1, &[0x3e, 0x28])?;
        ili9341.command(Command::VCOMControl2, &[0x86])?;
        ili9341.command(Command::MemoryAccessControl, &[0x48])?;
        ili9341.command(Command::PixelFormatSet, &[0x55])?;
        ili9341.command(Command::FrameControlNormal, &[0x00, 0x18])?;
        ili9341.command(Command::DisplayFunctionControl, &[0x08, 0x82, 0x27])?;
        ili9341.command(Command::Enable3G, &[0x00])?;
        ili9341.command(Command::GammaSet, &[0x01])?;
        ili9341.command(
            Command::PositiveGammaCorrection,
            &[
                0x0f, 0x31, 0x2b, 0x0c, 0x0e, 0x08, 0x4e, 0xf1, 0x37, 0x07, 0x10, 0x03, 0x0e, 0x09,
                0x00,
            ],
        )?;
        ili9341.command(
            Command::NegativeGammaCorrection,
            &[
                0x00, 0x0e, 0x14, 0x03, 0x11, 0x07, 0x31, 0xc1, 0x48, 0x08, 0x0f, 0x0c, 0x31, 0x36,
                0x0f,
            ],
        )?;
        ili9341.command(Command::SleepOut, &[])?;
        delay.delay_ms(120);
        ili9341.command(Command::DisplayOn, &[])?;

        Ok(ili9341)
    }

    fn hard_reset<DELAY: DelayMs<u16>>(&mut self, delay: &mut DELAY) {
        // set high if previously low
        self.reset.set_high();
        delay.delay_ms(200);
        // set low for reset
        self.reset.set_low();
        delay.delay_ms(200);
        // set high for normal operation
        self.reset.set_high();
        delay.delay_ms(200);
    }
    fn command(&mut self, cmd: Command, args: &[u8]) -> Result<(), Error<E>> {
        self.cs.set_low();

        self.dc.set_low();
        self.spi.write(&[cmd as u8]).map_err(Error::Spi)?;

        self.dc.set_high();
        self.spi.write(args).map_err(Error::Spi)?;

        self.cs.set_high();
        Ok(())
    }
    fn write_iter<I: IntoIterator<Item=u16>>(&mut self, data: I) -> Result<(), Error<E>> {
        self.cs.set_low();

        self.dc.set_low();
        self.spi.write(&[Command::MemoryWrite as u8]).map_err(Error::Spi)?;

        self.dc.set_high();
        for d in data.into_iter() {
            self.spi.write(&[(d>>8) as u8, (d&0xff) as u8]).map_err(Error::Spi)?;
        }

        self.cs.set_high();
        Ok(())
    }
    fn write_raw(&mut self, data: &[u8]) -> Result<(), Error<E>> {
        self.cs.set_low();

        self.dc.set_low();
        self.spi.write(&[Command::MemoryWrite as u8]).map_err(Error::Spi)?;

        self.dc.set_high();
        self.spi.write(data).map_err(Error::Spi)?;

        self.cs.set_high();
        Ok(())
    }
    fn set_window(&mut self, x0: u16, y0: u16, x1: u16, y1: u16) -> Result<(), Error<E>> {
        self.command(
            Command::ColumnAddressSet,
            &[
                (x0 >> 8) as u8,
                (x0 & 0xff) as u8,
                (x1 >> 8) as u8,
                (x1 & 0xff) as u8,
            ],
        )?;
        self.command(
            Command::PageAddressSet,
            &[
                (y0 >> 8) as u8,
                (y0 & 0xff) as u8,
                (y1 >> 8) as u8,
                (y1 & 0xff) as u8,
            ],
        )?;
        Ok(())
    }
    pub fn draw_iter<I: IntoIterator<Item=u16>>(&mut self, x0: u16, y0: u16, x1: u16, y1: u16, data: I) -> Result<(), Error<E>> {
        self.set_window(x0, y0, x1, y1)?;
        self.write_iter(data)
    }
    pub fn draw_raw(&mut self, x0: u16, y0: u16, x1: u16, y1: u16, data: &[u8]) -> Result<(), Error<E>> {
        self.set_window(x0, y0, x1, y1)?;
        self.write_raw(data)
    }
    pub fn set_rotation(&mut self, mode: u8) -> Result<(), Error<E>> {
        match mode%4 {
            0 => {
                self.width = 240;
                self.height = 320;
                self.command(Command::MemoryAccessControl, &[0x40|0x08])
            },
            1 => {
                self.width = 320;
                self.height = 240;
                self.command(Command::MemoryAccessControl, &[0x20|0x08])
            },
            2 => {
                self.width = 240;
                self.height = 320;
                self.command(Command::MemoryAccessControl, &[0x80|0x08])
            },
            3 => {
                self.width = 320;
                self.height = 240;
                self.command(Command::MemoryAccessControl, &[0x40|0x80|0x20|0x08])
            }
            _ => {
                unreachable!();
            }
        }
    }
    pub fn width(&self) -> usize {
        self.width
    }
    pub fn height(&self) -> usize {
        self.height
    }
}

#[derive(Clone, Copy)]
enum Command {
    SoftwareReset = 0x01,
    PowerControlA = 0xcb,
    PowerControlB = 0xcf,
    DriverTimingControlA = 0xe8,
    DriverTimingControlB = 0xea,
    PowerOnSequenceControl = 0xed,
    PumpRatioControl = 0xf7,
    PowerControl1 = 0xc0,
    PowerControl2 = 0xc1,
    VCOMControl1 = 0xc5,
    VCOMControl2 = 0xc7,
    MemoryAccessControl = 0x36,
    PixelFormatSet = 0x3a,
    FrameControlNormal = 0xb1,
    DisplayFunctionControl = 0xb6,
    Enable3G = 0xf2,
    GammaSet = 0x26,
    PositiveGammaCorrection = 0xe0,
    NegativeGammaCorrection = 0xe1,
    SleepOut = 0x11,
    DisplayOn = 0x29,
    ColumnAddressSet = 0x2a,
    PageAddressSet = 0x2b,
    MemoryWrite = 0x2c,
}