// Fenrir console screen reader.
// Copyright (c) 2026 Storm Dragon
// SPDX-License-Identifier: GPL-3.0-or-later
//
// 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 3 of the License, 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. If not, see <https://www.gnu.org/licenses/gpl-3.0.html>.

//go:build linux && cgo

package console

/*
#include <linux/kd.h>
#include <linux/keyboard.h>
#include <linux/input.h>
#include <sys/ioctl.h>
#include <errno.h>

static int ui_key_text(int fd, unsigned int code, int shift, int altgr) {
    if (code >= NR_KEYS) return 0;
    unsigned char leds = 0;
    if (ioctl(fd, KDGKBLED, &leds) < 0) return -errno;
    struct kbentry entry = {.kb_table = (shift ? 1 << KG_SHIFT : 0) |
        (altgr ? 1 << KG_ALTGR : 0), .kb_index = code};
    if (ioctl(fd, KDGKBENT, &entry) < 0) return -errno;
    if (KTYP(entry.kb_value) == KT_LETTER && (leds & LED_CAP)) {
        entry.kb_table ^= 1 << KG_SHIFT;
        if (ioctl(fd, KDGKBENT, &entry) < 0) return -errno;
    }
    unsigned int value = entry.kb_value;
    if (KTYP(value) == KT_LATIN || KTYP(value) == KT_LETTER) return KVAL(value);
    // The console encodes Unicode keysyms by inverting their high nibble.
    if (KTYP(value) >= 0x10) return value ^ 0xf000;
    return 0; // Compose/dead-key sequences are not text by themselves.
}
*/
import "C"

import (
	"os"
	"syscall"
	"unicode"

	"git.stormux.org/storm/fenrir/internal/input"
)

func (k *Keyboards) Capture(enabled bool) (result error) {
	if enabled {
		file, err := os.OpenFile("/dev/tty0", os.O_RDONLY|syscall.O_NOCTTY, 0)
		if err != nil {
			return err
		}
		defer func() {
			if result != nil {
				file.Close()
			}
		}()
		// Neutralize terminal-visible modifiers before taking modal ownership.
		for _, device := range k.devices {
			for _, code := range k.router.Forwarded(device.fd) {
				if err := device.forward(1, code, 0); err != nil {
					return err
				}
			}
			if err := device.forward(0, 0, 0); err != nil {
				return err
			}
		}
		if k.uiMap != nil {
			k.uiMap.Close()
		}
		k.uiMap = file
	} else if k.uiMap != nil {
		k.uiMap.Close()
		k.uiMap = nil
	}
	k.router.Capture(enabled)
	return nil
}

func (k *Keyboards) ui_text(code uint16, decision input.Decision) error {
	if decision.UI == nil || decision.UI.Name != "" || k.uiMap == nil {
		return nil
	}
	shift, altGr := C.int(0), C.int(0)
	if decision.UI.Shift {
		shift = 1
	}
	if decision.UI.AltGr {
		altGr = 1
	}
	value := int(C.ui_key_text(C.int(k.uiMap.Fd()), C.uint(code), shift, altGr))
	if value < 0 {
		return syscall.Errno(-value)
	}
	if value > 0 && unicode.IsPrint(rune(value)) {
		decision.UI.Text = string(rune(value))
	}
	return nil
}