#include <socks/tty.h>
#include <socks/input.h>
#include <socks/libc/ctype.h>

static void process_events(struct device *tty);

static char keycode_chars[] = {
	[KEY_UNKNOWN]                = ' ',
	[KEY_A]                      = 'a',
	[KEY_B]                      = 'b',
	[KEY_C]                      = 'c',
	[KEY_D]                      = 'd',
	[KEY_E]                      = 'e',
	[KEY_F]                      = 'f',
	[KEY_G]                      = 'g',
	[KEY_H]                      = 'h',
	[KEY_I]                      = 'i',
	[KEY_J]                      = 'j',
	[KEY_K]                      = 'k',
	[KEY_L]                      = 'l',
	[KEY_M]                      = 'm',
	[KEY_N]                      = 'n',
	[KEY_O]                      = 'o',
	[KEY_P]                      = 'p',
	[KEY_Q]                      = 'q',
	[KEY_R]                      = 'r',
	[KEY_S]                      = 's',
	[KEY_T]                      = 't',
	[KEY_U]                      = 'u',
	[KEY_V]                      = 'v',
	[KEY_W]                      = 'w',
	[KEY_X]                      = 'x',
	[KEY_Y]                      = 'y',
	[KEY_Z]                      = 'z',
	[KEY_KEY_1]                  = '1',
	[KEY_KEY_2]                  = '2',
	[KEY_KEY_3]                  = '3',
	[KEY_KEY_4]                  = '4',
	[KEY_KEY_5]                  = '5',
	[KEY_KEY_6]                  = '6',
	[KEY_KEY_7]                  = '7',
	[KEY_KEY_8]                  = '8',
	[KEY_KEY_9]                  = '9',
	[KEY_KEY_0]                  = '0',
	[KEY_ENTER]                  = '\n',
	[KEY_ESCAPE]                 = 0,
	[KEY_BACKSPACE]              = '\b',
	[KEY_TAB]                    = ' ',
	[KEY_SPACE]                  = ' ',
	[KEY_MINUS]                  = '-',
	[KEY_EQUALS]                 = '=',
	[KEY_LEFT_BRACE]             = '[',
	[KEY_RIGHT_BRACE]            = ']',
	[KEY_BACKSLASH]              = '\\',
	[KEY_NON_US_HASH]            = 0,
	[KEY_SEMICOLON]              = ';',
	[KEY_APOSTROPHE]             = '\'',
	[KEY_GRAVE_ACCENT]           = 0,
	[KEY_COMMA]                  = ',',
	[KEY_DOT]                    = '.',
	[KEY_SLASH]                  = '/',
	[KEY_CAPS_LOCK]              = 0,
	[KEY_F1]                     = 0,
	[KEY_F2]                     = 0,
	[KEY_F3]                     = 0,
	[KEY_F4]                     = 0,
	[KEY_F5]                     = 0,
	[KEY_F6]                     = 0,
	[KEY_F7]                     = 0,
	[KEY_F8]                     = 0,
	[KEY_F9]                     = 0,
	[KEY_F10]                    = 0,
	[KEY_F11]                    = 0,
	[KEY_F12]                    = 0,
	[KEY_PRINT_SCREEN]           = 0,
	[KEY_SCROLL_LOCK]            = 0,
	[KEY_PAUSE]                  = 0,
	[KEY_INSERT]                 = 0,
	[KEY_HOME]                   = 0,
	[KEY_PAGE_UP]                = 0,
	[KEY_DELETE]                 = 0,
	[KEY_END]                    = 0,
	[KEY_PAGE_DOWN]              = 0,
	[KEY_RIGHT]                  = 0,
	[KEY_LEFT]                   = 0,
	[KEY_DOWN]                   = 0,
	[KEY_UP]                     = 0,
	[KEY_NUM_LOCK]               = 0,
	[KEY_KEYPAD_SLASH]           = '/',
	[KEY_KEYPAD_ASTERISK]        = '*',
	[KEY_KEYPAD_MINUS]           = '-',
	[KEY_KEYPAD_PLUS]            = '+',
	[KEY_KEYPAD_ENTER]           = '\n',
	[KEY_KEYPAD_1]               = '1',
	[KEY_KEYPAD_2]               = '2',
	[KEY_KEYPAD_3]               = '3',
	[KEY_KEYPAD_4]               = '4',
	[KEY_KEYPAD_5]               = '5',
	[KEY_KEYPAD_6]               = '6',
	[KEY_KEYPAD_7]               = '7',
	[KEY_KEYPAD_8]               = '8',
	[KEY_KEYPAD_9]               = '9',
	[KEY_KEYPAD_0]               = '0',
	[KEY_KEYPAD_DOT]             = '.',
	[KEY_NON_US_BACKSLASH]       = 0,
	[KEY_KEYPAD_EQUALS]          = '=',
	[KEY_MENU]                   = 0,
	[KEY_LEFT_CTRL]              = 0,
	[KEY_LEFT_SHIFT]             = 0,
	[KEY_LEFT_ALT]               = 0,
	[KEY_LEFT_META]              = 0,
	[KEY_RIGHT_CTRL]             = 0,
	[KEY_RIGHT_SHIFT]            = 0,
	[KEY_RIGHT_ALT]              = 0,
	[KEY_RIGHT_META]             = 0,
	[KEY_MEDIA_MUTE]             = 0,
	[KEY_MEDIA_VOLUME_INCREMENT] = 0,
	[KEY_MEDIA_VOLUME_DECREMENT] = 0,
};

static char keycode_chars_shift[] = {
	[KEY_UNKNOWN]                = ' ',
	[KEY_A]                      = 'A',
	[KEY_B]                      = 'B',
	[KEY_C]                      = 'C',
	[KEY_D]                      = 'D',
	[KEY_E]                      = 'E',
	[KEY_F]                      = 'F',
	[KEY_G]                      = 'G',
	[KEY_H]                      = 'H',
	[KEY_I]                      = 'I',
	[KEY_J]                      = 'J',
	[KEY_K]                      = 'K',
	[KEY_L]                      = 'L',
	[KEY_M]                      = 'M',
	[KEY_N]                      = 'N',
	[KEY_O]                      = 'O',
	[KEY_P]                      = 'P',
	[KEY_Q]                      = 'Q',
	[KEY_R]                      = 'R',
	[KEY_S]                      = 'S',
	[KEY_T]                      = 'T',
	[KEY_U]                      = 'U',
	[KEY_V]                      = 'V',
	[KEY_W]                      = 'W',
	[KEY_X]                      = 'X',
	[KEY_Y]                      = 'Y',
	[KEY_Z]                      = 'Z',
	[KEY_KEY_1]                  = '!',
	[KEY_KEY_2]                  = '"',
	[KEY_KEY_3]                  = 0,
	[KEY_KEY_4]                  = '$',
	[KEY_KEY_5]                  = '%',
	[KEY_KEY_6]                  = '^',
	[KEY_KEY_7]                  = '&',
	[KEY_KEY_8]                  = '*',
	[KEY_KEY_9]                  = '(',
	[KEY_KEY_0]                  = ')',
	[KEY_ENTER]                  = '\n',
	[KEY_ESCAPE]                 = 0,
	[KEY_BACKSPACE]              = '\b',
	[KEY_TAB]                    = ' ',
	[KEY_SPACE]                  = ' ',
	[KEY_MINUS]                  = '_',
	[KEY_EQUALS]                 = '+',
	[KEY_LEFT_BRACE]             = '{',
	[KEY_RIGHT_BRACE]            = '}',
	[KEY_BACKSLASH]              = '|',
	[KEY_NON_US_HASH]            = 0,
	[KEY_SEMICOLON]              = ':',
	[KEY_APOSTROPHE]             = '@',
	[KEY_GRAVE_ACCENT]           = 0,
	[KEY_COMMA]                  = '<',
	[KEY_DOT]                    = '>',
	[KEY_SLASH]                  = '?',
	[KEY_CAPS_LOCK]              = 0,
	[KEY_F1]                     = 0,
	[KEY_F2]                     = 0,
	[KEY_F3]                     = 0,
	[KEY_F4]                     = 0,
	[KEY_F5]                     = 0,
	[KEY_F6]                     = 0,
	[KEY_F7]                     = 0,
	[KEY_F8]                     = 0,
	[KEY_F9]                     = 0,
	[KEY_F10]                    = 0,
	[KEY_F11]                    = 0,
	[KEY_F12]                    = 0,
	[KEY_PRINT_SCREEN]           = 0,
	[KEY_SCROLL_LOCK]            = 0,
	[KEY_PAUSE]                  = 0,
	[KEY_INSERT]                 = 0,
	[KEY_HOME]                   = 0,
	[KEY_PAGE_UP]                = 0,
	[KEY_DELETE]                 = 0,
	[KEY_END]                    = 0,
	[KEY_PAGE_DOWN]              = 0,
	[KEY_RIGHT]                  = 0,
	[KEY_LEFT]                   = 0,
	[KEY_DOWN]                   = 0,
	[KEY_UP]                     = 0,
	[KEY_NUM_LOCK]               = 0,
	[KEY_KEYPAD_SLASH]           = '/',
	[KEY_KEYPAD_ASTERISK]        = '*',
	[KEY_KEYPAD_MINUS]           = '-',
	[KEY_KEYPAD_PLUS]            = '+',
	[KEY_KEYPAD_ENTER]           = '\n',
	[KEY_KEYPAD_1]               = '1',
	[KEY_KEYPAD_2]               = '2',
	[KEY_KEYPAD_3]               = '3',
	[KEY_KEYPAD_4]               = '4',
	[KEY_KEYPAD_5]               = '5',
	[KEY_KEYPAD_6]               = '6',
	[KEY_KEYPAD_7]               = '7',
	[KEY_KEYPAD_8]               = '8',
	[KEY_KEYPAD_9]               = '9',
	[KEY_KEYPAD_0]               = '0',
	[KEY_KEYPAD_DOT]             = '.',
	[KEY_NON_US_BACKSLASH]       = 0,
	[KEY_KEYPAD_EQUALS]          = '=',
	[KEY_MENU]                   = 0,
	[KEY_LEFT_CTRL]              = 0,
	[KEY_LEFT_SHIFT]             = 0,
	[KEY_LEFT_ALT]               = 0,
	[KEY_LEFT_META]              = 0,
	[KEY_RIGHT_CTRL]             = 0,
	[KEY_RIGHT_SHIFT]            = 0,
	[KEY_RIGHT_ALT]              = 0,
	[KEY_RIGHT_META]             = 0,
	[KEY_MEDIA_MUTE]             = 0,
	[KEY_MEDIA_VOLUME_INCREMENT] = 0,
	[KEY_MEDIA_VOLUME_DECREMENT] = 0,
};

static struct tty_ldisc default_ldisc = {
	.name = "n_tty",
	.process_events = process_events,
};

static enum tty_modifier_key get_modifier_key(struct input_event *ev)
{
	switch (ev->ev_key.key) {
	case KEY_LEFT_CTRL:
	case KEY_RIGHT_CTRL:
		return TTY_KEY_CTRL;
	case KEY_LEFT_ALT:
	case KEY_RIGHT_ALT:
		return TTY_KEY_ALT;
	case KEY_LEFT_SHIFT:
	case KEY_RIGHT_SHIFT:
		return TTY_KEY_SHIFT;
	default:
		return TTY_KEY_OTHER;
	}
}

static void handle_modifier_keys(struct device *tty, enum tty_modifier_key modkey, struct input_event *ev)
{
	struct tty_device *ttydev = TTY_DEVICE(tty);

	if (ev->ev_key.state == INPUT_KEYSTATE_DOWN) {
		ttydev->tty_modstate |= modkey;
	} else {
		ttydev->tty_modstate &= ~modkey;
	}
}

static void convert_ev_to_chars(struct device *tty, struct input_event *ev)
{
	if (ev->ev_key.state == INPUT_KEYSTATE_UP) {
		return;
	}

	struct tty_device *ttydev = TTY_DEVICE(tty);

	char echo[2];
	int echo_len = 0;

	char c = keycode_chars[ev->ev_key.key];
	if (c == 0) {
		return;
	}

	if (ttydev->tty_modstate & TTY_KEY_CTRL) {
		if (!isalpha(c)) {
			return;
		}

		echo[0] = '^';
		echo[1] = toupper(c);
		echo_len = 2;

		c = tolower(c);
		c -= 97;
		c++;
	} else if (ttydev->tty_modstate & TTY_KEY_SHIFT) {
		c = keycode_chars_shift[ev->ev_key.key];
		echo[0] = c;
		echo_len = 1;
	} else {
		echo[0] = c;
		echo_len = 1;
	}

	if (c == 0) {
		return;
	}

	ringbuffer_write(&ttydev->tty_input, sizeof c, &c, S_NOBLOCK);
	size_t nr_written;
	tty_write(tty, echo, echo_len, &nr_written, S_NOBLOCK);
}

void process_events(struct device *tty)
{
	struct tty_device *ttydev = TTY_DEVICE(tty);
	struct ringbuffer *events = &ttydev->tty_events;

	struct input_event ev;

	size_t w = ringbuffer_read(events, sizeof ev, &ev, S_NOBLOCK);

	if (w != sizeof ev || ev.ev_type != INPUT_TYPE_KEY) {
		return;
	}

	enum tty_modifier_key modkeys = get_modifier_key(&ev);

	if (modkeys != TTY_KEY_OTHER) {
		handle_modifier_keys(tty, modkeys, &ev);
	} else {
		convert_ev_to_chars(tty, &ev);
	}
}

struct tty_ldisc *tty_default_line_discipline(void)
{
	return &default_ldisc;
}