/*
 * Translate key codes into ASCII
 *
 * Copyright (c) 2011 The Chromium OS Authors.
 * (C) Copyright 2004 DENX Software Engineering, Wolfgang Denk, wd@denx.de
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <common.h>
#include <stdio_dev.h>
#include <input.h>
#include <linux/input.h>

enum {
        /* These correspond to the lights on the keyboard */
        FLAG_NUM_LOCK           = 1 << 0,
        FLAG_CAPS_LOCK          = 1 << 1,
        FLAG_SCROLL_LOCK        = 1 << 2,

        /* Special flag ORed with key code to indicate release */
        KEY_RELEASE             = 1 << 15,
        KEY_MASK                = 0xfff,
};

/*
 * These takes map key codes to ASCII. 0xff means no key, or special key.
 * Three tables are provided - one for plain keys, one for when the shift
 * 'modifier' key is pressed and one for when the ctrl modifier key is
 * pressed.
 */
static const uchar kbd_plain_xlate[] = {
        0xff, 0x1b, '1',  '2',  '3',  '4',  '5',  '6',
        '7',  '8',  '9',  '0',  '-',  '=', '\b', '\t',  /* 0x00 - 0x0f */
        'q',  'w',  'e',  'r',  't',  'y',  'u',  'i',
        'o',  'p',  '[',  ']', '\r', 0xff,  'a',  's',  /* 0x10 - 0x1f */
        'd',  'f',  'g',  'h',  'j',  'k',  'l',  ';',
        '\'',  '`', 0xff, '\\', 'z',  'x',  'c',  'v',  /* 0x20 - 0x2f */
        'b',  'n',  'm',  ',' ,  '.', '/', 0xff, 0xff, 0xff,
        ' ', 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,        /* 0x30 - 0x3f */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,  '7',
        '8',  '9',  '-',  '4',  '5',  '6',  '+',  '1',  /* 0x40 - 0x4f */
        '2',  '3',  '0',  '.', 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x50 - 0x5F */
        '\r', 0xff, 0xff
};

static unsigned char kbd_shift_xlate[] = {
        0xff, 0x1b, '!', '@', '#', '$', '%', '^',
        '&', '*', '(', ')', '_', '+', '\b', '\t',       /* 0x00 - 0x0f */
        'Q', 'W', 'E', 'R', 'T', 'Y', 'U', 'I',
        'O', 'P', '{', '}', '\r', 0xff, 'A', 'S',       /* 0x10 - 0x1f */
        'D', 'F', 'G', 'H', 'J', 'K', 'L', ':',
        '"', '~', 0xff, '|', 'Z', 'X', 'C', 'V',        /* 0x20 - 0x2f */
        'B', 'N', 'M', '<', '>', '?', 0xff, 0xff, 0xff,
        ' ', 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,        /* 0x30 - 0x3f */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, '7',
        '8', '9', '-', '4', '5', '6', '+', '1', /* 0x40 - 0x4f */
        '2', '3', '0', '.', 0xff, 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,       /* 0x50 - 0x5F */
        '\r', 0xff, 0xff
};

static unsigned char kbd_ctrl_xlate[] = {
        0xff, 0x1b, '1', 0x00, '3', '4', '5', 0x1E,
        '7', '8', '9', '0', 0x1F, '=', '\b', '\t',      /* 0x00 - 0x0f */
        0x11, 0x17, 0x05, 0x12, 0x14, 0x18, 0x15, 0x09,
        0x0f, 0x10, 0x1b, 0x1d, '\n', 0xff, 0x01, 0x13, /* 0x10 - 0x1f */
        0x04, 0x06, 0x08, 0x09, 0x0a, 0x0b, 0x0c, ';',
        '\'', '~', 0x00, 0x1c, 0x1a, 0x18, 0x03, 0x16,  /* 0x20 - 0x2f */
        0x02, 0x0e, 0x0d, '<', '>', '?', 0xff, 0xff,
        0xff, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x30 - 0x3f */
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, '7',
        '8', '9', '-', '4', '5', '6', '+', '1',         /* 0x40 - 0x4f */
        '2', '3', '0', '.', 0xff, 0xff, 0xff, 0xff,
        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0x50 - 0x5F */
        '\r', 0xff, 0xff
};

/*
 * Scan key code to ANSI 3.64 escape sequence table.  This table is
 * incomplete in that it does not include all possible extra keys.
 */
static struct {
        int kbd_scan_code;
        char *escape;
} kbd_to_ansi364[] = {
        { KEY_UP, "\033[A"},
        { KEY_DOWN, "\033[B"},
        { KEY_RIGHT, "\033[C"},
        { KEY_LEFT, "\033[D"},
};

/* Maximum number of output characters that an ANSI sequence expands to */
#define ANSI_CHAR_MAX   3

static int input_queue_ascii(struct input_config *config, int ch)
{
        if (config->fifo_in + 1 == INPUT_BUFFER_LEN) {
                if (!config->fifo_out)
                        return -1; /* buffer full */
                else
                        config->fifo_in = 0;
        } else {
                if (config->fifo_in + 1 == config->fifo_out)
                        return -1; /* buffer full */
                config->fifo_in++;
        }
        config->fifo[config->fifo_in] = (uchar)ch;

        return 0;
}

int input_tstc(struct input_config *config)
{
        if (config->fifo_in == config->fifo_out && config->read_keys) {
                if (!(*config->read_keys)(config))
                        return 0;
        }
        return config->fifo_in != config->fifo_out;
}

int input_getc(struct input_config *config)
{
        int err = 0;

        while (config->fifo_in == config->fifo_out) {
                if (config->read_keys)
                        err = (*config->read_keys)(config);
                if (err)
                        return -1;
        }

        if (++config->fifo_out == INPUT_BUFFER_LEN)
                config->fifo_out = 0;

        return config->fifo[config->fifo_out];
}

/**
 * Process a modifier/special key press or release and decide which key
 * translation array should be used as a result.
 *
 * TODO: Should keep track of modifier press/release
 *
 * @param config        Input state
 * @param key           Key code to process
 * @param release       0 if a press, 1 if a release
 * @return pointer to keycode->ascii translation table that should be used
 */
static struct input_key_xlate *process_modifier(struct input_config *config,
                                                int key, int release)
{
        struct input_key_xlate *table;
        int flip = -1;
        int i;

        /* Start with the main table, and see what modifiers change it */
        assert(config->num_tables > 0);
        table = &config->table[0];
        for (i = 1; i < config->num_tables; i++) {
                struct input_key_xlate *tab = &config->table[i];

                if (key == tab->left_keycode || key == tab->right_keycode)
                        table = tab;
        }

        /* Handle the lighted keys */
        if (!release) {
                switch (key) {
                case KEY_SCROLLLOCK:
                        flip = FLAG_SCROLL_LOCK;
                        break;
                case KEY_NUMLOCK:
                        flip = FLAG_NUM_LOCK;
                        break;
                case KEY_CAPSLOCK:
                        flip = FLAG_CAPS_LOCK;
                        break;
                }
        }

        if (flip != -1) {
                int leds = 0;

                config->leds ^= flip;
                if (config->flags & FLAG_NUM_LOCK)
                        leds |= INPUT_LED_NUM;
                if (config->flags & FLAG_CAPS_LOCK)
                        leds |= INPUT_LED_CAPS;
                if (config->flags & FLAG_SCROLL_LOCK)
                        leds |= INPUT_LED_SCROLL;
                config->leds = leds;
        }

        return table;
}

/**
 * Search an int array for a key value
 *
 * @param array Array to search
 * @param count Number of elements in array
 * @param key   Key value to find
 * @return element where value was first found, -1 if none
 */
static int array_search(int *array, int count, int key)
{
        int i;

        for (i = 0; i < count; i++) {
                if (array[i] == key)
                        return i;
        }

        return -1;
}

/**
 * Sort an array so that those elements that exist in the ordering are
 * first in the array, and in the same order as the ordering. The algorithm
 * is O(count * ocount) and designed for small arrays.
 *
 * TODO: Move this to common / lib?
 *
 * @param dest          Array with elements to sort, also destination array
 * @param count         Number of elements to sort
 * @param order         Array containing ordering elements
 * @param ocount        Number of ordering elements
 * @return number of elements in dest that are in order (these will be at the
 *      start of dest).
 */
static int sort_array_by_ordering(int *dest, int count, int *order,
                                   int ocount)
{
        int temp[count];
        int dest_count;
        int same;       /* number of elements which are the same */
        int i;

        /* setup output items, copy items to be sorted into our temp area */
        memcpy(temp, dest, count * sizeof(*dest));
        dest_count = 0;

        /* work through the ordering, move over the elements we agree on */
        for (i = 0; i < ocount; i++) {
                if (array_search(temp, count, order[i]) != -1)
                        dest[dest_count++] = order[i];
        }
        same = dest_count;

        /* now move over the elements that are not in the ordering */
        for (i = 0; i < count; i++) {
                if (array_search(order, ocount, temp[i]) == -1)
                        dest[dest_count++] = temp[i];
        }
        assert(dest_count == count);
        return same;
}

/**
 * Check a list of key codes against the previous key scan
 *
 * Given a list of new key codes, we check how many of these are the same
 * as last time.
 *
 * @param config        Input state
 * @param keycode       List of key codes to examine
 * @param num_keycodes  Number of key codes
 * @param same          Returns number of key codes which are the same
 */
static int input_check_keycodes(struct input_config *config,
                           int keycode[], int num_keycodes, int *same)
{
        /* Select the 'plain' xlate table to start with */
        if (!config->num_tables) {
                debug("%s: No xlate tables: cannot decode keys\n", __func__);
                return -1;
        }

        /* sort the keycodes into the same order as the previous ones */
        *same = sort_array_by_ordering(keycode, num_keycodes,
                        config->prev_keycodes, config->num_prev_keycodes);

        memcpy(config->prev_keycodes, keycode, num_keycodes * sizeof(int));
        config->num_prev_keycodes = num_keycodes;

        return *same != num_keycodes;
}

/**
 * Checks and converts a special key code into ANSI 3.64 escape sequence.
 *
 * @param config        Input state
 * @param keycode       Key code to examine
 * @param output_ch     Buffer to place output characters into. It should
 *                      be at least ANSI_CHAR_MAX bytes long, to allow for
 *                      an ANSI sequence.
 * @param max_chars     Maximum number of characters to add to output_ch
 * @return number of characters output, if the key was converted, otherwise 0.
 *      This may be larger than max_chars, in which case the overflow
 *      characters are not output.
 */
static int input_keycode_to_ansi364(struct input_config *config,
                int keycode, char output_ch[], int max_chars)
{
        const char *escape;
        int ch_count;
        int i;

        for (i = ch_count = 0; i < ARRAY_SIZE(kbd_to_ansi364); i++) {
                if (keycode != kbd_to_ansi364[i].kbd_scan_code)
                        continue;
                for (escape = kbd_to_ansi364[i].escape; *escape; escape++) {
                        if (ch_count < max_chars)
                                output_ch[ch_count] = *escape;
                        ch_count++;
                }
                return ch_count;
        }

        return 0;
}

/**
 * Converts and queues a list of key codes in escaped ASCII string form
 * Convert a list of key codes into ASCII
 *
 * You must call input_check_keycodes() before this. It turns the keycode
 * list into a list of ASCII characters and sends them to the input layer.
 *
 * Characters which were seen last time do not generate fresh ASCII output.
 * The output (calls to queue_ascii) may be longer than num_keycodes, if the
 * keycode contains special keys that was encoded to longer escaped sequence.
 *
 * @param config        Input state
 * @param keycode       List of key codes to examine
 * @param num_keycodes  Number of key codes
 * @param output_ch     Buffer to place output characters into. It should
 *                      be at last ANSI_CHAR_MAX * num_keycodes, to allow for
 *                      ANSI sequences.
 * @param max_chars     Maximum number of characters to add to output_ch
 * @param same          Number of key codes which are the same
 * @return number of characters written into output_ch, or -1 if we would
 *      exceed max_chars chars.
 */
static int input_keycodes_to_ascii(struct input_config *config,
                int keycode[], int num_keycodes, char output_ch[],
                int max_chars, int same)
{
        struct input_key_xlate *table;
        int ch_count = 0;
        int i;

        table = &config->table[0];

        /* deal with modifiers first */
        for (i = 0; i < num_keycodes; i++) {
                int key = keycode[i] & KEY_MASK;

                if (key >= table->num_entries || table->xlate[key] == 0xff) {
                        table = process_modifier(config, key,
                                        keycode[i] & KEY_RELEASE);
                }
        }

        /* Start conversion by looking for the first new keycode (by same). */
        for (i = same; i < num_keycodes; i++) {
                int key = keycode[i];
                int ch = (key < table->num_entries) ? table->xlate[key] : 0xff;

                /*
                 * For a normal key (with an ASCII value), add it; otherwise
                 * translate special key to escape sequence if possible.
                 */
                if (ch != 0xff) {
                        if (ch_count < max_chars)
                                output_ch[ch_count] = (uchar)ch;
                        ch_count++;
                } else {
                        ch_count += input_keycode_to_ansi364(config, key,
                                                output_ch, max_chars);
                }
        }

        if (ch_count > max_chars) {
                debug("%s: Output char buffer overflow size=%d, need=%d\n",
                      __func__, max_chars, ch_count);
                return -1;
        }

        /* ok, so return keys */
        return ch_count;
}

int input_send_keycodes(struct input_config *config,
                        int keycode[], int num_keycodes)
{
        char ch[num_keycodes * ANSI_CHAR_MAX];
        int count, i, same = 0;
        int is_repeat = 0;
        unsigned delay_ms;

        config->modifiers = 0;
        if (!input_check_keycodes(config, keycode, num_keycodes, &same)) {
                /*
                 * Same as last time - is it time for another repeat?
                 * TODO(sjg@chromium.org) We drop repeats here and since
                 * the caller may not call in again for a while, our
                 * auto-repeat speed is not quite correct. We should
                 * insert another character if we later realise that we
                 * have missed a repeat slot.
                 */
                is_repeat = config->repeat_rate_ms &&
                        (int)get_timer(config->next_repeat_ms) >= 0;
                if (!is_repeat)
                        return 0;
        }

        count = input_keycodes_to_ascii(config, keycode, num_keycodes,
                                        ch, sizeof(ch), is_repeat ? 0 : same);
        for (i = 0; i < count; i++)
                input_queue_ascii(config, ch[i]);
        delay_ms = is_repeat ?
                        config->repeat_rate_ms :
                        config->repeat_delay_ms;

        config->next_repeat_ms = get_timer(0) + delay_ms;

        return count;
}

int input_add_table(struct input_config *config, int left_keycode,
                    int right_keycode, const uchar *xlate, int num_entries)
{
        struct input_key_xlate *table;

        if (config->num_tables == INPUT_MAX_MODIFIERS) {
                debug("%s: Too many modifier tables\n", __func__);
                return -1;
        }

        table = &config->table[config->num_tables++];
        table->left_keycode = left_keycode;
        table->right_keycode = right_keycode;
        table->xlate = xlate;
        table->num_entries = num_entries;

        return 0;
}

void input_set_delays(struct input_config *config, int repeat_delay_ms,
               int repeat_rate_ms)
{
        config->repeat_delay_ms = repeat_delay_ms;
        config->repeat_rate_ms = repeat_rate_ms;
}

int input_init(struct input_config *config, int leds)
{
        memset(config, '\0', sizeof(*config));
        config->leds = leds;
        if (input_add_table(config, -1, -1,
                        kbd_plain_xlate, ARRAY_SIZE(kbd_plain_xlate)) ||
                input_add_table(config, KEY_LEFTSHIFT, KEY_RIGHTSHIFT,
                        kbd_shift_xlate, ARRAY_SIZE(kbd_shift_xlate)) ||
                input_add_table(config, KEY_LEFTCTRL, KEY_RIGHTCTRL,
                        kbd_ctrl_xlate, ARRAY_SIZE(kbd_ctrl_xlate))) {
                debug("%s: Could not add modifier tables\n", __func__);
                return -1;
        }

        return 0;
}

int input_stdio_register(struct stdio_dev *dev)
{
        int error;

        error = stdio_register(dev);

        /* check if this is the standard input device */
        if (!error && strcmp(getenv("stdin"), dev->name) == 0) {
                /* reassign the console */
                if (OVERWRITE_CONSOLE ||
                                console_assign(stdin, dev->name))
                        return -1;
        }

        return 0;
}