/*
 * Copyright (C) 2014 Jared Boone, ShareBrained Technology, Inc.
 *
 * This file is part of PortaPack.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street,
 * Boston, MA 02110-1301, USA.
 */

#ifndef __PORTAPACK_IO_H__
#define __PORTAPACK_IO_H__

#include <cstdint>
#include <cstddef>
#include <array>

#include "platform.hpp"
#include "gpio.hpp"
#include "ui.hpp"

namespace portapack {

class IO {
   public:
    enum class TouchPinsConfig : uint8_t {
        XN_BIT = (1 << 0),
        XP_BIT = (1 << 1),
        YN_BIT = (1 << 2),
        YP_BIT = (1 << 3),

        XN_OE = (1 << 4),
        XP_OE = (1 << 5),
        YN_OE = (1 << 6),
        YP_OE = (1 << 7),

        XN_IN = XN_BIT,
        XN_OUT_1 = XN_OE | XN_BIT,
        XN_OUT_0 = XN_OE,

        XP_IN = XP_BIT,
        XP_OUT_1 = XP_OE | XP_BIT,
        XP_OUT_0 = XP_OE,

        YN_IN = YN_BIT,
        YN_OUT_1 = YN_OE | YN_BIT,
        YN_OUT_0 = YN_OE,

        YP_IN = YP_BIT,
        YP_OUT_1 = YP_OE | YP_BIT,
        YP_OUT_0 = YP_OE,

        /* Allow pins to be pulled up by CPLD pull-ups. */
        Float = XP_IN | XN_IN | YP_IN | YN_IN,

        /* Drive one plane to 0V, other plane is pulled up. Watch for when pulled-up
         * plane falls to ~0V.
         */
        WaitTouch = XP_OUT_0 | XN_OUT_0 | YP_IN | YN_IN,

        /* Create a voltage divider between X plane, touch resistance, Y plane. */
        SensePressure = XP_IN | XN_OUT_0 | YP_OUT_1 | YN_IN,

        /* Create a voltage divider across X plane, read voltage from Y plane. */
        SenseX = XP_OUT_1 | XN_OUT_0 | YP_IN | YN_IN,

        /* Create a voltage divider across Y plane, read voltage from X plane. */
        SenseY = XP_IN | XN_IN | YP_OUT_1 | YN_OUT_0,
    };

    constexpr IO(
        GPIO gpio_dir,
        GPIO gpio_lcd_rdx,
        GPIO gpio_lcd_wrx,
        GPIO gpio_io_stbx,
        GPIO gpio_addr,
        GPIO gpio_rot_a,
        GPIO gpio_rot_b)
        : gpio_dir{gpio_dir},
          gpio_lcd_rdx{gpio_lcd_rdx},
          gpio_lcd_wrx{gpio_lcd_wrx},
          gpio_io_stbx{gpio_io_stbx},
          gpio_addr{gpio_addr},
          gpio_rot_a{gpio_rot_a},
          gpio_rot_b{gpio_rot_b} {};

    void init();

    void lcd_backlight(const bool value);
    void lcd_reset_state(const bool active);
    void audio_reset_state(const bool active);
    void reference_oscillator(const bool enable);

    void lcd_data_write_command_and_data(
        const uint_fast8_t command,
        const uint8_t* data,
        const size_t data_count) {
        lcd_command(command);
        for (size_t i = 0; i < data_count; i++) {
            lcd_write_data(data[i]);
        }
    }

    void lcd_data_write_command_and_data(
        const uint_fast8_t command,
        const std::initializer_list<uint8_t>& data) {
        lcd_command(command);
        for (const auto d : data) {
            lcd_write_data(d);
        }
    }

    void lcd_data_read_command_and_data(
        const uint_fast8_t command,
        uint16_t* const data,
        const size_t data_count) {
        lcd_command(command);
        for (size_t i = 0; i < data_count; i++) {
            data[i] = lcd_read_data();
        }
    }

    void lcd_write_word(const uint32_t w) {
        lcd_write_data(w);
    }

    void lcd_write_words(const uint16_t* const w, size_t n) {
        for (size_t i = 0; i < n; i++) {
            lcd_write_data(w[i]);
        }
    }

    void lcd_write_pixel(const ui::Color pixel) {
        lcd_write_data(pixel.v);
    }

    uint32_t lcd_read_word() {
        return lcd_read_data();
    }

    void lcd_write_pixels(const ui::Color pixel, size_t n) {
        while (n--) {
            lcd_write_data(pixel.v);
        }
    }

    void lcd_write_pixels_unrolled8(const ui::Color pixel, size_t n) {
        auto v = pixel.v;
        n >>= 3;
        while (n--) {
            lcd_write_data(v);
            lcd_write_data(v);
            lcd_write_data(v);
            lcd_write_data(v);
            lcd_write_data(v);
            lcd_write_data(v);
            lcd_write_data(v);
            lcd_write_data(v);
        }
    }

    void lcd_write_pixels(const ui::Color* const pixels, size_t n) {
        for (size_t i = 0; i < n; i++) {
            lcd_write_pixel(pixels[i]);
        }
    }

    void lcd_read_bytes(uint8_t* byte, size_t byte_count) {
        size_t word_count = byte_count / 2;
        while (word_count) {
            const auto word = lcd_read_data();
            *(byte++) = word >> 8;
            *(byte++) = word >> 0;
            word_count--;
        }
        if (byte_count & 1) {
            const auto word = lcd_read_data();
            *(byte++) = word >> 8;
        }
    }

    uint32_t io_read() {
        io_stb_assert();
        dir_read();
        addr_0();
        __asm__("nop");
        __asm__("nop");
        __asm__("nop");
        const auto switches_raw = data_read();
        io_stb_deassert();

        return switches_raw;
    }

    uint32_t io_update(const TouchPinsConfig write_value);

    uint32_t lcd_te() {
        return gpio_rot_a.read();
    }

    uint32_t dfu_read() {
        return gpio_rot_b.read();
    }

   private:
    const GPIO gpio_dir;
    const GPIO gpio_lcd_rdx;
    const GPIO gpio_lcd_wrx;
    const GPIO gpio_io_stbx;
    const GPIO gpio_addr;
    const GPIO gpio_rot_a;
    const GPIO gpio_rot_b;

    static constexpr ioportid_t gpio_data_port_id = 3;
    static constexpr size_t gpio_data_shift = 8;
    static constexpr ioportmask_t gpio_data_mask = 0xffU << gpio_data_shift;

    uint8_t io_reg{0x03};

    void lcd_rd_assert() {
        gpio_lcd_rdx.clear();
    }

    void lcd_rd_deassert() {
        gpio_lcd_rdx.set();
    }

    void lcd_wr_assert() {
        gpio_lcd_wrx.clear();
    }

    void lcd_wr_deassert() {
        gpio_lcd_wrx.set();
    }

    void io_stb_assert() {
        gpio_io_stbx.clear();
    }

    void io_stb_deassert() {
        gpio_io_stbx.set();
    }

    void addr(const bool value) {
        gpio_addr.write(value);
    }

    void addr_1() {
        gpio_addr.set();
    }

    void addr_0() {
        gpio_addr.clear();
    }

    void data_mask_set() {
        LPC_GPIO->MASK[gpio_data_port_id] = ~gpio_data_mask;
    }

    void dir_write() {
        gpio_dir.clear();
        LPC_GPIO->DIR[gpio_data_port_id] |= gpio_data_mask;
        /* TODO: Manipulating DIR[3] makes me queasy. The RFFC5072 DATA pin
         * is also on port 3, and switches direction periodically...
         * Time to resort to bit-banding to enforce atomicity? But then, how
         * to change direction on eight bits efficiently? Or do I care, since
         * the PortaPack data bus shouldn't change direction too frequently?
         */
    }

    void dir_read() {
        LPC_GPIO->DIR[gpio_data_port_id] &= ~gpio_data_mask;
        gpio_dir.set();
    }

    void data_write_low(const uint32_t value) {
        LPC_GPIO->MPIN[gpio_data_port_id] = (value << gpio_data_shift);
    }

    void data_write_high(const uint32_t value) {
        LPC_GPIO->MPIN[gpio_data_port_id] = value;
    }

    uint32_t data_read() {
        return (LPC_GPIO->MPIN[gpio_data_port_id] >> gpio_data_shift) & 0xffU;
    }

    void lcd_command(const uint32_t value) {
        data_write_high(0); /* Drive high byte (with zero -- don't care) */
        dir_write();        /* Turn around data bus, MCU->CPLD */
        addr(0);            /* Indicate command */
        __asm__("nop");
        __asm__("nop");
        __asm__("nop");
        lcd_wr_assert(); /* Latch high byte */

        data_write_low(value); /* Drive low byte (pass-through) */
        __asm__("nop");
        __asm__("nop");
        __asm__("nop");
        lcd_wr_deassert(); /* Complete write operation */

        addr(1); /* Set up for data phase (most likely after a command) */
    }

    void lcd_write_data(const uint32_t value) __attribute__((always_inline)) {
        // NOTE: Assumes and DIR=0 and ADDR=1 from command phase.
        data_write_high(value); /* Drive high byte */
        __asm__("nop");
        lcd_wr_assert(); /* Latch high byte */

        data_write_low(value); /* Drive low byte (pass-through) */
        __asm__("nop");
        __asm__("nop");
        __asm__("nop");
        lcd_wr_deassert(); /* Complete write operation */
    }

    uint32_t lcd_read_data() {
        // NOTE: Assumes ADDR=1 from command phase.
        dir_read();

        /* Start read operation */
        lcd_rd_assert();
        /* Wait for passthrough data(15:8) to settle -- ~16ns (3 cycles) typical */
        /* Wait for read control L duration (355ns) */
        halPolledDelay(71);  // 355ns
        const auto value_high = data_read();

        /* Latch data[7:0] */
        lcd_rd_deassert();
        /* Wait for latched data[7:0] to settle -- ~26ns (5 cycles) typical */
        /* Wait for read control H duration (90ns) */
        halPolledDelay(18);  // 90ns

        const auto value_low = data_read();
        return (value_high << 8) | value_low;
    }

    void io_write(const bool address, const uint_fast16_t value) {
        data_write_low(value);
        dir_write();
        addr(address);
        __asm__("nop");
        __asm__("nop");
        __asm__("nop");
        io_stb_assert();
        __asm__("nop");
        __asm__("nop");
        __asm__("nop");
        io_stb_deassert();
    }
    /*
        void lcd_data_write_command_and_data(
                const uint_fast16_t command,
                const uint8_t* const data,
                const size_t count
        ) {
                lcd_data_write_command(command);
                for(size_t i=0; i<count; i++) {
                        lcd_data_write_data(data[i]);
                }
        }
*/
};

extern IO io;

} /* namespace portapack */

#endif /*__PORTAPACK_IO_H__*/