//
//  fileprovider.cpp
//  AdPlug
//
//  Created by Christopher Snowhill on 1/27/18.
//  Copyright © 2021 Christopher Snowhill. All rights reserved.
//

#include "fileprovider.h"

class binistream_cog : public binistream
{
    id<CogSource> m_file;
    
    Byte m_buffer[4096];
    int m_buffer_filled, m_buffer_position;
    
public:
    binistream_cog( id<CogSource> p_file )
    : m_file( p_file ), m_buffer_filled( 0 ), m_buffer_position( 0 ) { }
    
    void seek( long pos, Offset offs )
    {
        switch (offs)
        {
            case Set: break;
            
            case Add:
                if ( ( pos < 0 && m_buffer_position + pos >= 0 ) ||
                    ( pos >= 0 && m_buffer_position + pos < m_buffer_filled + m_buffer_position ) )
                {
                    m_buffer_filled -= pos;
                    m_buffer_position += pos;
                    err &= ~Eof;
                    return;
                }
                else
                    pos += [m_file tell] - m_buffer_filled;
                break;
                
            case End:
                [m_file seek:0 whence:SEEK_END];
                pos += [m_file tell];
                break;
        }
        [m_file seek:0 whence:SEEK_END];
        if (pos < [m_file tell])
        {
            err &= ~Eof;
            [m_file seek:pos whence:SEEK_SET];
        }
        
        m_buffer_filled = 0;
        m_buffer_position = 0;
    }
    
    long pos()
    {
        return [m_file tell] - m_buffer_filled;
    }
    
    Byte getByte()
    {
        if ( err & Eof ) return -1;
        
        if ( ! m_buffer_filled )
        {
            m_buffer_filled = (int) [m_file read:m_buffer amount:4096];
            if ( ! m_buffer_filled )
            {
                err |= Eof;
                return -1;
            }
            m_buffer_position = 0;
        }
        
        Byte value = m_buffer[ m_buffer_position ];
        ++m_buffer_position;
        --m_buffer_filled;
        return value;
    }
};

binistream * CProvider_cog::open(std::string filename) const
{
    id<CogSource> p_file;
    
    if ( filename == m_file_path )
    {
        p_file = m_file_hint;
        [p_file seek:0 whence:SEEK_SET];
    }
    
    if ( p_file == nil )
    {
        NSString * urlString = [NSString stringWithUTF8String:filename.c_str()];
        NSString * fragmentString = @"";
        NSRange fragmentRange = [urlString rangeOfString:@"#" options:NSBackwardsSearch];
        if (fragmentRange.location != NSNotFound) {
            fragmentString = [urlString substringFromIndex:fragmentRange.location];
            urlString = [urlString substringToIndex:fragmentRange.location];
        }
        NSURL * url = [NSURL URLWithString:[[urlString stringByAddingPercentEncodingWithAllowedCharacters:NSCharacterSet.URLFragmentAllowedCharacterSet] stringByAppendingString:fragmentString]];
        id audioSourceClass = NSClassFromString(@"AudioSource");
        p_file = [audioSourceClass audioSourceForURL:url];
        
        if (![p_file open:url])
            return 0;
    }
    
    binistream_cog * f = new binistream_cog( p_file );
    if ( f->error() ) { delete f; return 0; }
    
    f->setFlag(binio::BigEndian, false); f->setFlag(binio::FloatIEEE);
    
    return f;
}

void CProvider_cog::close(binistream *f) const
{
    binistream_cog * ff = ( binistream_cog * ) f;
    if ( f )
        delete ff;
}