//
// Created by rick on 23-03-20.
//
#include "keyboard.h"

#include <kprint.h>
#include <drivers/ports.h>
#include <cpu/isr.h>
#include <libc/libc.h>
#include <libc/stdbool.h>
#include <libc/ringqueue.h>
#include <mem/mem.h>


const char scancode_map_lowercase[] = {
        0, 0, '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', 0, 0, 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i',
        'o', 'p', '[', ']', 0, 0, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`', 0, '\\', 'z', 'x', 'c',
        'v', 'b', 'n', 'm', ',', '.', '/', 0, 0, 0, ' ', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0, 0
};

const char scancode_map_uppercase[] = {
        0, 0, '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '_', '+', 0, 0, 'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I',
        'O', 'P', '{', '}', 0, 0, 'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', '"', '~', 0, '|', 'Z', 'X', 'C',
        'V', 'B', 'N', 'M', '<', '>', '?', 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0
};

//
//char scancodes_ascii[] = {
//        0, 0,
//        '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', 0,
//        0, 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']', 0,
//        0, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`',
//        0, '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/', 0,
//        '*',
//        0, ' ',
//        0,
//        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // F1-F10
//        0, 0,
//        '7', '8', '9', '-',
//        '4', '5', '6', '+',
//        '1', '2', '3',
//        '0', 0,
//        0, // sysrq
//        0, 0, // weird
//        0, 0, // F11 F12
//        // weid
//};

struct {
    u8 shift: 1;
    u8 ctrl: 1;
    u8 alt: 1;
    u8 extended: 1;
} keyboard_state;

void *keyboard_event_buffer = NULL;

char *MSG_KEY = "Clicked on key 'x'\n";

char getc() {
    while (true) {
        KeyEvent* event = get_next_event();
        char retval = 0;
        if (event == NULL) {
            goto _getc_end;
        }
        if (event->is_release) {
            goto _getc_end;
        }
        if (event->scancode == 0x1C) {
            retval = '\n';
            goto _getc_end;
        }
        if (event->ascii_code != 0) {
            retval = event->ascii_code;
            goto _getc_end;
        }
        _getc_end:
        free_event(event);
        if (retval != 0) {
            return retval;
        }
    }
}

KeyEvent *get_next_event() {
    KeyEvent *target = malloc(sizeof(KeyEvent));
    if (!ring_buffer_get(keyboard_event_buffer, target)) {
        asm("hlt");
        free(target);
        return NULL;
    }
    return target;
};

void free_event(KeyEvent *event) {
    free(event);
}

//void print_scancode(unsigned char scancode);

void handle_modifier_keys(unsigned char scancode, bool is_release) {
    switch (scancode) {
        case 42:
        case 54:
            keyboard_state.shift = !is_release;
            break;
        case 29:
            keyboard_state.ctrl = !is_release;
            break;
        case 56:
            keyboard_state.alt = !is_release;
            break;
        default:
            // not an modifier key
            break;
    }
}

void publish_key_event(unsigned char scan_code) {
    bool is_release = false;
    if (scan_code > 0x80) {
        is_release = true;
        scan_code -= 0x80;
    }
    handle_modifier_keys(scan_code, is_release);

    char ascii_char = scancode_map_lowercase[scan_code];
    if (keyboard_state.shift) {
        if (scancode_map_uppercase[scan_code] != 0) {
            ascii_char = scancode_map_uppercase[scan_code];
        }
    }

    KeyEvent event = {
            .scancode = scan_code,
            .ascii_code = ascii_char,
            .is_release = !is_release,
            .shift = keyboard_state.shift,
            .alt = keyboard_state.alt,
            .ctrl = keyboard_state.ctrl,
    };
    ring_buffer_put(keyboard_event_buffer, &event);
}

static void keyboard_callback(registers_t regs) {
    unsigned char status = port_byte_in(PORT_PS2_STATUS);
    // check if data available
    if ((status & 0b00000001) == 0) {
        return;
    }
    unsigned char scancode = port_byte_in(PORT_PS2_DATA);
    publish_key_event(scancode);
//    print_scancode(scancode);
}

void init_keyboard() {
    register_interrupt_handler(IRQ1, keyboard_callback);
    keyboard_state.shift = 0;
    keyboard_state.ctrl = 0;
    keyboard_state.alt = 0;
    keyboard_state.extended = 0;
    keyboard_event_buffer = create_buffer(256, sizeof(KeyEvent));
}

//void print_scancode(unsigned char scancode) {
//    char msg[256];
//    char release = 0;
//    if (scancode > 0x80) {
//        // release
//        release = 1;
//        scancode -= 0x80;
//    }
//    char code = scancodes_ascii[scancode];
//    if (code == 0) {
//        // special
//    } else {
//        if (release && code > 0x60 && code < 0x7B) {
//            code -= 0x20; // to lowercase
//        }
//
//        strcpy(msg, MSG_KEY);
//        msg[strlen(msg) - 3] = code;
//        kprint(msg);
//    }
//}