#include <kernel/interrupts/interrupts.h>
#include <kernel/io/io.h>
#include <kernel/graphics/vesa.h>

int shift_pressed = 0;

char keymap[128] = {
        0 /*E*/, 27, '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', '-', '=', '\b',
        '\t', 'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']', '\n',
        0 /*C*/, 'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`', 14 /*LS*/,
        '\\', 'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/', 14 /*RS*/, '*',
        0, // Alt key
        ' ', // Space bar
        15, // Caps lock
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // F keys
        0, // Num lock
        0, // Scroll lock
        0, // Home key
        0, // Up arrow
        0, // Page up
        '-',
        0, // Left arrow
        0,
        0, // Right arrow
        '+',
        0, // End key
        0, // Down arrow
        0, // Page down
        0, // Insert key
        0, // Delete key
        0, 0, 0,
        0, // F11
        0, // F12
        0, // Other keys
};

char shift_keymap[128] = {
        0 /*E*/, 27, '!', '@', '#', '$', '%', '^', '&', '*', '(', ')', '_', '+', '\b',
        '\t', 'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I', 'O', 'P', '{', '}', '\n',
        0 /*C*/, 'A', 'S', 'D', 'F', 'G', 'H', 'J', 'K', 'L', ':', '"', '~', 14 /*LS*/,
        '|', 'Z', 'X', 'C', 'V', 'B', 'N', 'M', '<', '>', '?', 14 /*RS*/, '*',
        0, // Alt key
        ' ', // Space bar
        15, // Caps lock
        0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // F keys
        0, // Num lock
        0, // Scroll lock
        0, // Home key
        0, // Up arrow
        0, // Page up
        '-',
        0, // Left arrow
        0,
        0, // Right arrow
        '+',
        0, // End key
        0, // Down arrow
        0, // Page down
        0, // Insert key
        0, // Delete key
        0, 0, 0,
        0, // F11
        0, // F12
        0, // Other keys
};

void keyboard_handler(struct regs *r) {
    unsigned char scan_code;
    char *current_keymap = keymap;
    if (shift_pressed) current_keymap = shift_keymap;

    scan_code = receive_b(0x60);

    if ((scan_code & 0x80) == 0) { // PRESS
        // TODO: Fix caps lock deactivation when pressing shift while shifted
        if (current_keymap[scan_code] == 14 || (current_keymap[scan_code] == 15 && !shift_pressed)) {
            shift_pressed = 1;
            return;
        } else if (current_keymap[scan_code] == 15 && shift_pressed) {
            shift_pressed = 0;
            return;
        }
        vesa_keyboard_char(current_keymap[scan_code]);
    } else { // RELEASE
        char key = current_keymap[scan_code];
        if (key == 14) shift_pressed = 0;
    }
}

void keyboard_acknowledge() {
    while (receive_b(0x60) != 0xfa);
}

void keyboard_rate() {
    send_b(0x60, 0xF3);
    keyboard_acknowledge();
    send_b(0x60, 0x0); // Rate{00000} Delay{00} 0
}

// Installs the keyboard handler into IRQ1
void keyboard_install() {
    keyboard_rate();
    irq_install_handler(1, keyboard_handler);
    vga_log("Installed keyboard handler", 5);
}