/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 *
 * Copyright (C) 2005 Dave Chapman
 *
 * 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 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <inttypes.h>
#include "platform.h"
#include "metadata.h"
#include "metadata_common.h"

/* Define LOGF_ENABLE to enable logf output in this file */
/*#define LOGF_ENABLE*/
#include "logf.h"

/* Read an Ogg page header. file->packet_remaining is set to the size of the
 * first packet on the page; file->packet_ended is set to true if the packet
 * ended on the current page. Returns true if the page header was
 * successfully read.
 */
static bool file_read_page_header(struct ogg_file* file)
{
    unsigned char buffer[64];
    ssize_t table_left;

    /* Size of page header without segment table */
    if (read(file->fd, buffer, 27) != 27)
    {
        return false;
    }
        
    if (memcmp("OggS", buffer, 4))
    {
        return false;
    }

    /* Skip pattern (4), version (1), flags (1), granule position (8),
     * serial (4), pageno (4), checksum (4)
     */
    table_left = buffer[26];
    file->packet_remaining = 0;

    /* Read segment table for the first packet */
    do
    {
        ssize_t count = MIN(sizeof(buffer), (size_t) table_left);
        int i;

        if (read(file->fd, buffer, count) < count)
        {
            return false;
        }
        
        table_left -= count;
        
        for (i = 0; i < count; i++)
        {
            file->packet_remaining += buffer[i];
            
            if (buffer[i] < 255)
            {
                file->packet_ended = true;
                
                /* Skip remainder of the table */
                if (lseek(file->fd, table_left, SEEK_CUR) < 0)
                {
                    return false;
                }
                
                table_left = 0;
                break;
            }
        }
    }
    while (table_left > 0);
    
    return true;
}


/* Read (up to) buffer_size of data from the file. If buffer is NULL, just
 * skip ahead buffer_size bytes (like lseek). Returns number of bytes read,
 * 0 if there is no more data to read (in the packet or the file), < 0 if a
 * read error occurred.
 */
ssize_t ogg_file_read(struct ogg_file* file, void* buffer, size_t buffer_size)
{
    ssize_t done = 0;
    ssize_t count = -1;
    
    do
    {
        if (file->packet_remaining <= 0)
        {
            if (file->packet_ended)
            {
                break;
            }

            if (!file_read_page_header(file))
            {
                count = -1;
                break;
            }
        }

        count = MIN(buffer_size, (size_t) file->packet_remaining);

        if (buffer)
        {
            count = read(file->fd, buffer, count);
        }
        else
        {
            if (lseek(file->fd, count, SEEK_CUR) < 0)
            {
                count = -1;
            }
        }
        
        if (count <= 0)
        {
            break;
        }

        if (buffer)
        {
            buffer += count;
        }

        buffer_size -= count;
        done += count;
        file->packet_remaining -= count;
    }
    while (buffer_size > 0);

    return (count < 0 ? count : done);
}


/* Read an int32 from file. Returns false if a read error occurred.
 */
static bool file_read_int32(struct ogg_file* file, int32_t* value)
{
    char buf[sizeof(int32_t)];

    if (ogg_file_read(file, buf, sizeof(buf)) < (ssize_t) sizeof(buf))
    {
        return false;
    }
    
    *value = get_long_le(buf);
    return true;
}


/* Read a string from the file. Read up to buffer_size bytes, or, if eos
 * != -1, until the eos character is found (eos is not stored in buf,
 * unless it is nil). Writes up to buffer_size chars to buf, always
 * terminating with a nil. Returns number of chars read or < 0 if a read
 * error occurred.
 *
 * Unfortunately this is a slightly modified copy of read_string() in
 * metadata_common.c...
 */
static long file_read_string(struct ogg_file* file, char* buffer,
    long buffer_size, int eos, long size)
{
    long read_bytes = 0;
    
    while (size > 0)
    {
        char c;

        if (ogg_file_read(file, &c, 1) != 1)
        {
            read_bytes = -1;
            break;
        }
        
        read_bytes++;
        size--;
        
        if ((eos != -1) && (eos == (unsigned char) c))
        {
            break;
        }
        
        if (buffer_size > 1)
        {
            *buffer++ = c;
            buffer_size--;
        }
        else if (eos == -1)
        {
            /* No point in reading any more, skip remaining data */
            if (ogg_file_read(file, NULL, size) < 0)
            {
                read_bytes = -1;
            }
            else
            {
                read_bytes += size;
            }
            
            break;
        }
    }
    
    *buffer = 0;
    return read_bytes;
}


/* Init struct file for reading from fd. type is the AFMT_* codec type of
 * the file, and determines if Ogg pages are to be read. remaining is the
 * max amount to read if codec type is FLAC; it is ignored otherwise.
 * Returns true if the file was successfully initialized.
 */
bool ogg_file_init(struct ogg_file* file, int fd, int type, int remaining)
{
    memset(file, 0, sizeof(*file));
    file->fd = fd;
    
    if (type == AFMT_OGG_VORBIS || type == AFMT_SPEEX || type == AFMT_OPUS)
    {
        if (!file_read_page_header(file))
        {
            return false;
        }
    }

    if (type == AFMT_OGG_VORBIS)
    {
        char buffer[7];

        /* Read packet header (type and id string) */
        if (ogg_file_read(file, buffer, sizeof(buffer)) < (ssize_t) sizeof(buffer))
        {
            return false;
        }

        /* The first byte of a packet is the packet type; comment packets
         * are type 3.
         */
        if (buffer[0] != 3)
        {
            return false;
        }
    }
    else if (type == AFMT_OPUS)
    {
        char buffer[8];

        /* Read comment header */
        if (ogg_file_read(file, buffer, sizeof(buffer)) < (ssize_t) sizeof(buffer))
        {
            return false;
        }

        /* Should be equal to "OpusTags" */
        if (memcmp(buffer, "OpusTags", 8) != 0)
        {
            return false;
        }
    }
    else if (type == AFMT_FLAC)
    {
        file->packet_remaining = remaining;
        file->packet_ended = true;
    }
    
    return true;
}

#define B64_START_CHAR '+'
/* maps char codes to BASE64 codes ('A': 0, 'B': 1,... '+': 62, '-': 63 */
const signed char b64_codes[] =
{   /* Starts from first valid base 64 char '+' with char code 43 (B64_START_CHAR)
     * For valid base64 chars: index in 0..63; for invalid: -1, for =: -2 */
    62, -1, -1, -1, 63, /* 43-47 (+ /) */
    52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -2, -1, -1, /* 48-63 (0-9 and =) */
    -1,  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, /* 64-79 (A-O) */
    15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, /* 80-95 (P-Z) */
    -1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, /* 96-111 (a-o) */
    41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 /* 112-127 (p-z) */
};

size_t base64_decode(const char *in, size_t in_len, unsigned char *out)
{
    size_t i = 0;
    int val = 0;
    size_t len = 0;

    while (i < in_len)
    {
        if (in[i] == '=') //is it padding?
        {
            switch (i & 3)
            {
                case 2:
                    out[len++] = (val >> 4) & 0xFF;
                break;
                case 3:
                    out[len++] = (val >> 10) & 0xFF;
                out[len++] = (val >>  2) & 0xFF;
                break;
            }
            break;
        }
        int index = in[i] - B64_START_CHAR;
#ifdef SIMULATOR
        if (index < 0 || index >= (int)ARRAYLEN(b64_codes) || b64_codes[index] < 0)
        {
            DEBUGF("Invalid base64 char: '%c', char code: %i.\n", in[i], in[i]);
            break;
        }
#endif
        val = (val << 6) | b64_codes[index];

        if ((++i & 3) == 0)
        {
            out[len++] = (val >> 16) & 0xFF;
            out[len++] = (val >> 8) & 0xFF;
            out[len++] = val & 0xFF;
        }
    }
    return len;
}

size_t base64_encoded_size(size_t inlen)
{
    size_t ret = inlen;
    if (inlen % 3 != 0)
        ret += 3 - (inlen % 3);
    ret /= 3;
    ret *= 4;

    return ret;
}

/* Read the items in a Vorbis comment packet. For Ogg files, the file must
 * be located on a page start, for other files, the beginning of the comment
 * data (i.e., the vendor string length). Returns total size of the
 * comments, or 0 if there was a read error.
 */
long read_vorbis_tags(int fd, struct mp3entry *id3, 
    long tag_remaining)
{
    struct ogg_file file;
    char *buf = id3->id3v2buf;
    int32_t comment_count;
    int32_t len;
    long comment_size = 0;
    int buf_remaining = sizeof(id3->id3v2buf) + sizeof(id3->id3v1buf);
    int i;
    
    if (!ogg_file_init(&file, fd, id3->codectype, tag_remaining))
    {
        return 0;
    }
    
    /* Skip vendor string */

    if (!file_read_int32(&file, &len) || (ogg_file_read(&file, NULL, len) < 0))
    {
        return 0;
    }

    if (!file_read_int32(&file, &comment_count))
    {
        return 0;
    }
    
    comment_size += 4 + len + 4;

    for (i = 0; i < comment_count && file.packet_remaining > 0; i++)
    {
        char name[TAG_NAME_LENGTH];
        int32_t read_len;

        if (!file_read_int32(&file, &len))
        {
            return 0;
        }
        
        comment_size += 4 + len;
        read_len = file_read_string(&file, name, sizeof(name), '=', len);
        
        if (read_len < 0)
        {
            return 0;
        }

        len -= read_len;
#ifdef HAVE_ALBUMART
        int before_block_pos = lseek(fd, 0, SEEK_CUR);
#endif
        read_len = file_read_string(&file, id3->path, sizeof(id3->path), -1, len);

        if (read_len < 0)
        {
            return 0;
        }

        logf("Vorbis comment %d: %s=%s", i, name, id3->path);
#ifdef HAVE_ALBUMART
        if (!id3->has_embedded_albumart /* only use the first PICTURE */
            && !strcasecmp(name, "METADATA_BLOCK_PICTURE"))
        {
            int after_block_pos = lseek(fd, 0, SEEK_CUR);

            char* buf = id3->path;
            size_t outlen = base64_decode(buf, MIN(read_len, (int32_t) sizeof(id3->path) - 1), buf);

            int picframe_pos;
            parse_flac_album_art(buf, outlen, &id3->albumart.type, &picframe_pos);
            if(id3->albumart.type != AA_TYPE_UNKNOWN)
            {
                //NOTE: This is not exact location due to padding in base64 (up to 3 chars)!!
                // But it's OK with our jpeg decoder if we add or miss few bytes in jpeg header
                const int picframe_pos_b64 = base64_encoded_size(picframe_pos + 4);

                id3->has_embedded_albumart = true;
                id3->albumart.type |= AA_FLAG_VORBIS_BASE64;
                id3->albumart.pos = picframe_pos_b64 + before_block_pos;
                id3->albumart.size = after_block_pos - id3->albumart.pos;
            }
            continue;
        }
#endif
        /* Is it an embedded cuesheet? */
        if (!strcasecmp(name, "CUESHEET"))
        {
            id3->has_embedded_cuesheet = true;
            id3->embedded_cuesheet.pos = lseek(file.fd, 0, SEEK_CUR) - read_len;
            id3->embedded_cuesheet.size = len;
            id3->embedded_cuesheet.encoding = CHAR_ENC_UTF_8;
            continue;
        }

        len = parse_tag(name, id3->path, id3, buf, buf_remaining, TAGTYPE_VORBIS);

        buf += len;
        buf_remaining -= len;
    }

    /* Skip to the end of the block (needed by FLAC) */
    if (file.packet_remaining)
    {
        if (ogg_file_read(&file, NULL, file.packet_remaining) < 0)
        {
            return 0;
        }
    }

    return comment_size;
}