// SPDX-License-Identifier: GPL-2.0+
/* speakup_keyhelp.c
 * help module for speakup
 *
 *written by David Borowski.
 *
 *  Copyright (C) 2003  David Borowski.
 */

#include <linux/keyboard.h>
#include "spk_priv.h"
#include "speakup.h"

#define MAXFUNCS 130
#define MAXKEYS 256
static const int num_key_names = MSG_KEYNAMES_END - MSG_KEYNAMES_START + 1;
static u_short key_offsets[MAXFUNCS], key_data[MAXKEYS];
static u_short masks[] = { 32, 16, 8, 4, 2, 1 };

static short letter_offsets[26] = {
        -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1, -1, -1, -1, -1, -1, -1,
        -1, -1 };

static u_char funcvals[] = {
        ATTRIB_BLEEP_DEC, ATTRIB_BLEEP_INC, BLEEPS_DEC, BLEEPS_INC,
        SAY_FIRST_CHAR, SAY_LAST_CHAR, SAY_CHAR, SAY_CHAR_NUM,
        SAY_NEXT_CHAR, SAY_PHONETIC_CHAR, SAY_PREV_CHAR, SPEAKUP_PARKED,
        SPEAKUP_CUT, EDIT_DELIM, EDIT_EXNUM, EDIT_MOST,
        EDIT_REPEAT, EDIT_SOME, SPEAKUP_GOTO, BOTTOM_EDGE,
        LEFT_EDGE, RIGHT_EDGE, TOP_EDGE, SPEAKUP_HELP,
        SAY_LINE, SAY_NEXT_LINE, SAY_PREV_LINE, SAY_LINE_INDENT,
        SPEAKUP_PASTE, PITCH_DEC, PITCH_INC, PUNCT_DEC,
        PUNCT_INC, PUNC_LEVEL_DEC, PUNC_LEVEL_INC, SPEAKUP_QUIET,
        RATE_DEC, RATE_INC, READING_PUNC_DEC, READING_PUNC_INC,
        SAY_ATTRIBUTES, SAY_FROM_LEFT, SAY_FROM_TOP, SAY_POSITION,
        SAY_SCREEN, SAY_TO_BOTTOM, SAY_TO_RIGHT, SPK_KEY,
        SPK_LOCK, SPEAKUP_OFF, SPEECH_KILL, SPELL_DELAY_DEC,
        SPELL_DELAY_INC, SPELL_WORD, SPELL_PHONETIC, TONE_DEC,
        TONE_INC, VOICE_DEC, VOICE_INC, VOL_DEC,
        VOL_INC, CLEAR_WIN, SAY_WIN, SET_WIN,
        ENABLE_WIN, SAY_WORD, SAY_NEXT_WORD, SAY_PREV_WORD, 0
};

static u_char *state_tbl;
static int cur_item, nstates;

static void build_key_data(void)
{
        u_char *kp, counters[MAXFUNCS], ch, ch1;
        u_short *p_key, key;
        int i, offset = 1;

        nstates = (int)(state_tbl[-1]);
        memset(counters, 0, sizeof(counters));
        memset(key_offsets, 0, sizeof(key_offsets));
        kp = state_tbl + nstates + 1;
        while (*kp++) {
                /* count occurrences of each function */
                for (i = 0; i < nstates; i++, kp++) {
                        if (!*kp)
                                continue;
                        if ((state_tbl[i] & 16) != 0 && *kp == SPK_KEY)
                                continue;
                        counters[*kp]++;
                }
        }
        for (i = 0; i < MAXFUNCS; i++) {
                if (counters[i] == 0)
                        continue;
                key_offsets[i] = offset;
                offset += (counters[i] + 1);
                if (offset >= MAXKEYS)
                        break;
        }
/* leave counters set so high keycodes come first.
 * this is done so num pad and other extended keys maps are spoken before
 * the alpha with speakup type mapping.
 */
        kp = state_tbl + nstates + 1;
        while ((ch = *kp++)) {
                for (i = 0; i < nstates; i++) {
                        ch1 = *kp++;
                        if (!ch1)
                                continue;
                        if ((state_tbl[i] & 16) != 0 && ch1 == SPK_KEY)
                                continue;
                        key = (state_tbl[i] << 8) + ch;
                        counters[ch1]--;
                        offset = key_offsets[ch1];
                        if (!offset)
                                continue;
                        p_key = key_data + offset + counters[ch1];
                        *p_key = key;
                }
        }
}

static void say_key(int key)
{
        int i, state = key >> 8;

        key &= 0xff;
        for (i = 0; i < 6; i++) {
                if (state & masks[i])
                        synth_printf(" %s", spk_msg_get(MSG_STATES_START + i));
        }
        if ((key > 0) && (key <= num_key_names))
                synth_printf(" %s\n",
                             spk_msg_get(MSG_KEYNAMES_START + (key - 1)));
}

static int help_init(void)
{
        char start = SPACE;
        int i;
        int num_funcs = MSG_FUNCNAMES_END - MSG_FUNCNAMES_START + 1;

        state_tbl = spk_our_keys[0] + SHIFT_TBL_SIZE + 2;
        for (i = 0; i < num_funcs; i++) {
                char *cur_funcname = spk_msg_get(MSG_FUNCNAMES_START + i);

                if (start == *cur_funcname)
                        continue;
                start = *cur_funcname;
                letter_offsets[(start & 31) - 1] = i;
        }
        return 0;
}

int spk_handle_help(struct vc_data *vc, u_char type, u_char ch, u_short key)
{
        int i, n;
        char *name;
        u_char func, *kp;
        u_short *p_keys, val;

        if (letter_offsets[0] == -1)
                help_init();
        if (type == KT_LATIN) {
                if (ch == SPACE) {
                        spk_special_handler = NULL;
                        synth_printf("%s\n", spk_msg_get(MSG_LEAVING_HELP));
                        return 1;
                }
                ch |= 32; /* lower case */
                if (ch < 'a' || ch > 'z')
                        return -1;
                if (letter_offsets[ch - 'a'] == -1) {
                        synth_printf(spk_msg_get(MSG_NO_COMMAND), ch);
                        synth_printf("\n");
                        return 1;
                }
                cur_item = letter_offsets[ch - 'a'];
        } else if (type == KT_CUR) {
                if (ch == 0 &&
                    (MSG_FUNCNAMES_START + cur_item + 1) <= MSG_FUNCNAMES_END)
                        cur_item++;
                else if (ch == 3 && cur_item > 0)
                        cur_item--;
                else
                        return -1;
        } else if (type == KT_SPKUP && ch == SPEAKUP_HELP &&
                   !spk_special_handler) {
                spk_special_handler = spk_handle_help;
                synth_printf("%s\n", spk_msg_get(MSG_HELP_INFO));
                build_key_data(); /* rebuild each time in case new mapping */
                return 1;
        } else {
                name = NULL;
                if ((type != KT_SPKUP) && (key > 0) && (key <= num_key_names)) {
                        synth_printf("%s\n",
                                     spk_msg_get(MSG_KEYNAMES_START + key - 1));
                        return 1;
                }
                for (i = 0; funcvals[i] != 0 && !name; i++) {
                        if (ch == funcvals[i])
                                name = spk_msg_get(MSG_FUNCNAMES_START + i);
                }
                if (!name)
                        return -1;
                kp = spk_our_keys[key] + 1;
                for (i = 0; i < nstates; i++) {
                        if (ch == kp[i])
                                break;
                }
                key += (state_tbl[i] << 8);
                say_key(key);
                synth_printf(spk_msg_get(MSG_KEYDESC), name);
                synth_printf("\n");
                return 1;
        }
        name = spk_msg_get(MSG_FUNCNAMES_START + cur_item);
        func = funcvals[cur_item];
        synth_printf("%s", name);
        if (key_offsets[func] == 0) {
                synth_printf(" %s\n", spk_msg_get(MSG_IS_UNASSIGNED));
                return 1;
        }
        p_keys = key_data + key_offsets[func];
        for (n = 0; p_keys[n]; n++) {
                val = p_keys[n];
                if (n > 0)
                        synth_printf("%s ", spk_msg_get(MSG_DISJUNCTION));
                say_key(val);
        }
        return 1;
}