/* see copyright notice in squirrel.h */
#include <new>
#include <stdio.h>
#include <squirrel.h>
#include <sqstdio.h>
#include "sqstdstream.h"

#define SQSTD_FILE_TYPE_TAG ((SQUnsignedInteger)(SQSTD_STREAM_TYPE_TAG | 0x00000001))
//basic API
SQFILE sqstd_fopen(const SQChar *filename ,const SQChar *mode)
{
#ifndef SQUNICODE
    return (SQFILE)fopen(filename,mode);
#else
    return (SQFILE)_wfopen(filename,mode);
#endif
}

SQInteger sqstd_fread(void* buffer, SQInteger size, SQInteger count, SQFILE file)
{
    SQInteger ret = (SQInteger)fread(buffer,size,count,(FILE *)file);
    return ret;
}

SQInteger sqstd_fwrite(const SQUserPointer buffer, SQInteger size, SQInteger count, SQFILE file)
{
    return (SQInteger)fwrite(buffer,size,count,(FILE *)file);
}

SQInteger sqstd_fseek(SQFILE file, SQInteger offset, SQInteger origin)
{
    SQInteger realorigin;
    switch(origin) {
        case SQ_SEEK_CUR: realorigin = SEEK_CUR; break;
        case SQ_SEEK_END: realorigin = SEEK_END; break;
        case SQ_SEEK_SET: realorigin = SEEK_SET; break;
        default: return -1; //failed
    }
    return fseek((FILE *)file,(long)offset,(int)realorigin);
}

SQInteger sqstd_ftell(SQFILE file)
{
    return ftell((FILE *)file);
}

SQInteger sqstd_fflush(SQFILE file)
{
    return fflush((FILE *)file);
}

SQInteger sqstd_fclose(SQFILE file)
{
    return fclose((FILE *)file);
}

SQInteger sqstd_feof(SQFILE file)
{
    return feof((FILE *)file);
}

//File
struct SQFile : public SQStream {
    SQFile() { _handle = NULL; _owns = false;}
    SQFile(SQFILE file, bool owns) { _handle = file; _owns = owns;}
    virtual ~SQFile() { Close(); }
    bool Open(const SQChar *filename ,const SQChar *mode) {
        Close();
        if( (_handle = sqstd_fopen(filename,mode)) ) {
            _owns = true;
            return true;
        }
        return false;
    }
    void Close() {
        if(_handle && _owns) {
            sqstd_fclose(_handle);
            _handle = NULL;
            _owns = false;
        }
    }
    SQInteger Read(void *buffer,SQInteger size) {
        return sqstd_fread(buffer,1,size,_handle);
    }
    SQInteger Write(void *buffer,SQInteger size) {
        return sqstd_fwrite(buffer,1,size,_handle);
    }
    SQInteger Flush() {
        return sqstd_fflush(_handle);
    }
    SQInteger Tell() {
        return sqstd_ftell(_handle);
    }
    SQInteger Len() {
        SQInteger prevpos=Tell();
        Seek(0,SQ_SEEK_END);
        SQInteger size=Tell();
        Seek(prevpos,SQ_SEEK_SET);
        return size;
    }
    SQInteger Seek(SQInteger offset, SQInteger origin)  {
        return sqstd_fseek(_handle,offset,origin);
    }
    bool IsValid() { return _handle?true:false; }
    bool EOS() { return Tell()==Len()?true:false;}
    SQFILE GetHandle() {return _handle;}
private:
    SQFILE _handle;
    bool _owns;
};

static SQInteger _file__typeof(HSQUIRRELVM v)
{
    sq_pushstring(v,_SC("file"),-1);
    return 1;
}

static SQInteger _file_releasehook(SQUserPointer p, SQInteger SQ_UNUSED_ARG(size))
{
    SQFile *self = (SQFile*)p;
    self->~SQFile();
    sq_free(self,sizeof(SQFile));
    return 1;
}

static SQInteger _file_constructor(HSQUIRRELVM v)
{
    const SQChar *filename,*mode;
    bool owns = true;
    SQFile *f;
    SQFILE newf;
    if(sq_gettype(v,2) == OT_STRING && sq_gettype(v,3) == OT_STRING) {
        sq_getstring(v, 2, &filename);
        sq_getstring(v, 3, &mode);
        newf = sqstd_fopen(filename, mode);
        if(!newf) return sq_throwerror(v, _SC("cannot open file"));
    } else if(sq_gettype(v,2) == OT_USERPOINTER) {
        owns = !(sq_gettype(v,3) == OT_NULL);
        sq_getuserpointer(v,2,&newf);
    } else {
        return sq_throwerror(v,_SC("wrong parameter"));
    }

    f = new (sq_malloc(sizeof(SQFile)))SQFile(newf,owns);
    if(SQ_FAILED(sq_setinstanceup(v,1,f))) {
        f->~SQFile();
        sq_free(f,sizeof(SQFile));
        return sq_throwerror(v, _SC("cannot create blob with negative size"));
    }
    sq_setreleasehook(v,1,_file_releasehook);
    return 0;
}

static SQInteger _file_close(HSQUIRRELVM v)
{
    SQFile *self = NULL;
    if(SQ_SUCCEEDED(sq_getinstanceup(v,1,(SQUserPointer*)&self,(SQUserPointer)SQSTD_FILE_TYPE_TAG))
        && self != NULL)
    {
        self->Close();
    }
    return 0;
}

//bindings
#define _DECL_FILE_FUNC(name,nparams,typecheck) {_SC(#name),_file_##name,nparams,typecheck}
static const SQRegFunction _file_methods[] = {
    _DECL_FILE_FUNC(constructor,3,_SC("x")),
    _DECL_FILE_FUNC(_typeof,1,_SC("x")),
    _DECL_FILE_FUNC(close,1,_SC("x")),
    {NULL,(SQFUNCTION)0,0,NULL}
};



SQRESULT sqstd_createfile(HSQUIRRELVM v, SQFILE file,SQBool own)
{
    SQInteger top = sq_gettop(v);
    sq_pushregistrytable(v);
    sq_pushstring(v,_SC("std_file"),-1);
    if(SQ_SUCCEEDED(sq_get(v,-2))) {
        sq_remove(v,-2); //removes the registry
        sq_pushroottable(v); // push the this
        sq_pushuserpointer(v,file); //file
        if(own){
            sq_pushinteger(v,1); //true
        }
        else{
            sq_pushnull(v); //false
        }
        if(SQ_SUCCEEDED( sq_call(v,3,SQTrue,SQFalse) )) {
            sq_remove(v,-2);
            return SQ_OK;
        }
    }
    sq_settop(v,top);
    return SQ_ERROR;
}

SQRESULT sqstd_getfile(HSQUIRRELVM v, SQInteger idx, SQFILE *file)
{
    SQFile *fileobj = NULL;
    if(SQ_SUCCEEDED(sq_getinstanceup(v,idx,(SQUserPointer*)&fileobj,(SQUserPointer)SQSTD_FILE_TYPE_TAG))) {
        *file = fileobj->GetHandle();
        return SQ_OK;
    }
    return sq_throwerror(v,_SC("not a file"));
}



#define IO_BUFFER_SIZE 2048
struct IOBuffer {
    unsigned char buffer[IO_BUFFER_SIZE];
    SQInteger size;
    SQInteger ptr;
    SQFILE file;
};

SQInteger _read_byte(IOBuffer *iobuffer)
{
    if(iobuffer->ptr < iobuffer->size) {

        SQInteger ret = iobuffer->buffer[iobuffer->ptr];
        iobuffer->ptr++;
        return ret;
    }
    else {
        if( (iobuffer->size = sqstd_fread(iobuffer->buffer,1,IO_BUFFER_SIZE,iobuffer->file )) > 0 )
        {
            SQInteger ret = iobuffer->buffer[0];
            iobuffer->ptr = 1;
            return ret;
        }
    }

    return 0;
}

SQInteger _read_two_bytes(IOBuffer *iobuffer)
{
    if(iobuffer->ptr < iobuffer->size) {
        if(iobuffer->size < 2) return 0;
        SQInteger ret = *((const wchar_t*)&iobuffer->buffer[iobuffer->ptr]);
        iobuffer->ptr += 2;
        return ret;
    }
    else {
        if( (iobuffer->size = sqstd_fread(iobuffer->buffer,1,IO_BUFFER_SIZE,iobuffer->file )) > 0 )
        {
            if(iobuffer->size < 2) return 0;
            SQInteger ret = *((const wchar_t*)&iobuffer->buffer[0]);
            iobuffer->ptr = 2;
            return ret;
        }
    }

    return 0;
}

static SQInteger _io_file_lexfeed_PLAIN(SQUserPointer iobuf)
{
    IOBuffer *iobuffer = (IOBuffer *)iobuf;
    return _read_byte(iobuffer);

}

#ifdef SQUNICODE
static SQInteger _io_file_lexfeed_UTF8(SQUserPointer iobuf)
{
    IOBuffer *iobuffer = (IOBuffer *)iobuf;
#define READ(iobuf) \
    if((inchar = (unsigned char)_read_byte(iobuf)) == 0) \
        return 0;

    static const SQInteger utf8_lengths[16] =
    {
        1,1,1,1,1,1,1,1,        /* 0000 to 0111 : 1 byte (plain ASCII) */
        0,0,0,0,                /* 1000 to 1011 : not valid */
        2,2,                    /* 1100, 1101 : 2 bytes */
        3,                      /* 1110 : 3 bytes */
        4                       /* 1111 :4 bytes */
    };
    static const unsigned char byte_masks[5] = {0,0,0x1f,0x0f,0x07};
    unsigned char inchar;
    SQInteger c = 0;
    READ(iobuffer);
    c = inchar;
    //
    if(c >= 0x80) {
        SQInteger tmp;
        SQInteger codelen = utf8_lengths[c>>4];
        if(codelen == 0)
            return 0;
            //"invalid UTF-8 stream";
        tmp = c&byte_masks[codelen];
        for(SQInteger n = 0; n < codelen-1; n++) {
            tmp<<=6;
            READ(iobuffer);
            tmp |= inchar & 0x3F;
        }
        c = tmp;
    }
    return c;
}
#endif

static SQInteger _io_file_lexfeed_UCS2_LE(SQUserPointer iobuf)
{
    SQInteger ret;
    IOBuffer *iobuffer = (IOBuffer *)iobuf;
    if( (ret = _read_two_bytes(iobuffer)) > 0 )
        return ret;
    return 0;
}

static SQInteger _io_file_lexfeed_UCS2_BE(SQUserPointer iobuf)
{
    SQInteger c;
    IOBuffer *iobuffer = (IOBuffer *)iobuf;
    if( (c = _read_two_bytes(iobuffer)) > 0 ) {
        c = ((c>>8)&0x00FF)| ((c<<8)&0xFF00);
        return c;
    }
    return 0;
}

SQInteger file_read(SQUserPointer file,SQUserPointer buf,SQInteger size)
{
    SQInteger ret;
    if( ( ret = sqstd_fread(buf,1,size,(SQFILE)file ))!=0 )return ret;
    return -1;
}

SQInteger file_write(SQUserPointer file,SQUserPointer p,SQInteger size)
{
    return sqstd_fwrite(p,1,size,(SQFILE)file);
}

SQRESULT sqstd_loadfile(HSQUIRRELVM v,const SQChar *filename,SQBool printerror)
{
    SQFILE file = sqstd_fopen(filename,_SC("rb"));

    SQInteger ret;
    unsigned short us;
    unsigned char uc;
    SQLEXREADFUNC func = _io_file_lexfeed_PLAIN;
    if(file){
        ret = sqstd_fread(&us,1,2,file);
        if(ret != 2) {
            //probably an empty file
            us = 0;
        }
        if(us == SQ_BYTECODE_STREAM_TAG) { //BYTECODE
            sqstd_fseek(file,0,SQ_SEEK_SET);
            if(SQ_SUCCEEDED(sq_readclosure(v,file_read,file))) {
                sqstd_fclose(file);
                return SQ_OK;
            }
        }
        else { //SCRIPT

            switch(us)
            {
                //gotta swap the next 2 lines on BIG endian machines
                case 0xFFFE: func = _io_file_lexfeed_UCS2_BE; break;//UTF-16 little endian;
                case 0xFEFF: func = _io_file_lexfeed_UCS2_LE; break;//UTF-16 big endian;
                case 0xBBEF:
                    if(sqstd_fread(&uc,1,sizeof(uc),file) == 0) {
                        sqstd_fclose(file);
                        return sq_throwerror(v,_SC("io error"));
                    }
                    if(uc != 0xBF) {
                        sqstd_fclose(file);
                        return sq_throwerror(v,_SC("Unrecognized encoding"));
                    }
#ifdef SQUNICODE
                    func = _io_file_lexfeed_UTF8;
#else
                    func = _io_file_lexfeed_PLAIN;
#endif
                    break;//UTF-8 ;
                default: sqstd_fseek(file,0,SQ_SEEK_SET); break; // ascii
            }
            IOBuffer buffer;
            buffer.ptr = 0;
            buffer.size = 0;
            buffer.file = file;
            if(SQ_SUCCEEDED(sq_compile(v,func,&buffer,filename,printerror))){
                sqstd_fclose(file);
                return SQ_OK;
            }
        }
        sqstd_fclose(file);
        return SQ_ERROR;
    }
    return sq_throwerror(v,_SC("cannot open the file"));
}

SQRESULT sqstd_dofile(HSQUIRRELVM v,const SQChar *filename,SQBool retval,SQBool printerror)
{
    //at least one entry must exist in order for us to push it as the environment
    if(sq_gettop(v) == 0)
        return sq_throwerror(v,_SC("environment table expected"));

    if(SQ_SUCCEEDED(sqstd_loadfile(v,filename,printerror))) {
        sq_push(v,-2);
        if(SQ_SUCCEEDED(sq_call(v,1,retval,SQTrue))) {
            sq_remove(v,retval?-2:-1); //removes the closure
            return 1;
        }
        sq_pop(v,1); //removes the closure
    }
    return SQ_ERROR;
}

SQRESULT sqstd_writeclosuretofile(HSQUIRRELVM v,const SQChar *filename)
{
    SQFILE file = sqstd_fopen(filename,_SC("wb+"));
    if(!file) return sq_throwerror(v,_SC("cannot open the file"));
    if(SQ_SUCCEEDED(sq_writeclosure(v,file_write,file))) {
        sqstd_fclose(file);
        return SQ_OK;
    }
    sqstd_fclose(file);
    return SQ_ERROR; //forward the error
}

SQInteger _g_io_loadfile(HSQUIRRELVM v)
{
    const SQChar *filename;
    SQBool printerror = SQFalse;
    sq_getstring(v,2,&filename);
    if(sq_gettop(v) >= 3) {
        sq_getbool(v,3,&printerror);
    }
    if(SQ_SUCCEEDED(sqstd_loadfile(v,filename,printerror)))
        return 1;
    return SQ_ERROR; //propagates the error
}

SQInteger _g_io_writeclosuretofile(HSQUIRRELVM v)
{
    const SQChar *filename;
    sq_getstring(v,2,&filename);
    if(SQ_SUCCEEDED(sqstd_writeclosuretofile(v,filename)))
        return 1;
    return SQ_ERROR; //propagates the error
}

SQInteger _g_io_dofile(HSQUIRRELVM v)
{
    const SQChar *filename;
    SQBool printerror = SQFalse;
    sq_getstring(v,2,&filename);
    if(sq_gettop(v) >= 3) {
        sq_getbool(v,3,&printerror);
    }
    sq_push(v,1); //repush the this
    if(SQ_SUCCEEDED(sqstd_dofile(v,filename,SQTrue,printerror)))
        return 1;
    return SQ_ERROR; //propagates the error
}

#define _DECL_GLOBALIO_FUNC(name,nparams,typecheck) {_SC(#name),_g_io_##name,nparams,typecheck}
static const SQRegFunction iolib_funcs[]={
    _DECL_GLOBALIO_FUNC(loadfile,-2,_SC(".sb")),
    _DECL_GLOBALIO_FUNC(dofile,-2,_SC(".sb")),
    _DECL_GLOBALIO_FUNC(writeclosuretofile,3,_SC(".sc")),
    {NULL,(SQFUNCTION)0,0,NULL}
};

SQRESULT sqstd_register_iolib(HSQUIRRELVM v)
{
    SQInteger top = sq_gettop(v);
    //create delegate
    declare_stream(v,_SC("file"),(SQUserPointer)SQSTD_FILE_TYPE_TAG,_SC("std_file"),_file_methods,iolib_funcs);
    sq_pushstring(v,_SC("stdout"),-1);
    sqstd_createfile(v,stdout,SQFalse);
    sq_newslot(v,-3,SQFalse);
    sq_pushstring(v,_SC("stdin"),-1);
    sqstd_createfile(v,stdin,SQFalse);
    sq_newslot(v,-3,SQFalse);
    sq_pushstring(v,_SC("stderr"),-1);
    sqstd_createfile(v,stderr,SQFalse);
    sq_newslot(v,-3,SQFalse);
    sq_settop(v,top);
    return SQ_OK;
}