/*
 * AUTHOR
 * N. Nielsen
 *
 * LICENSE
 * This software is in the public domain.
 *
 * The software is provided "as is", without warranty of any kind,
 * express or implied, including but not limited to the warranties
 * of merchantability, fitness for a particular purpose, and
 * noninfringement. In no event shall the author(s) be liable for any
 * claim, damages, or other liability, whether in an action of
 * contract, tort, or otherwise, arising from, out of, or in connection
 * with the software or the use or other dealings in the software.
 *
 * SUPPORT
 * Send bug reports to: <nielsen@memberwebs.com>
 */

/* =========================================================================
 *  Main RLIB
 *  2000-2001 Copyright, Nate Nielsen
 */

#include <stdarg.h>
#include "common/usuals.h"
#include "common/compat.h"
#include "lib/rlib.h"
#include "priv.h"
#include "rep.h"
#include "common/binfile.h"
#include "common/repfile.h"

/* rlibInit: --------------------------------------------------------------
 *  Initialize a stream. We already expect stream to be zero'd
 */

int rlibInit(r_stream* stream, long options)
{
	byte* op = NULL;
	int i, j;
	struct internal_state* state;

	if(stream->state != NULL)
		return R_INVARG;

	/*  Allocate a state */
	state = stream->state =
		(struct internal_state*)malloc(sizeof(struct internal_state));

	if(!state)
		return R_NOMEM;

	zero(*state);

	/* Init the stream for the current session */
	if(!vmInit(stream))
		return R_NOMEM;

	state->options = options;

	/*  Init our case table */
	/*  we only do this once for the whole bunch */
	for (i = 0; i < 256; i++)
	   stream->state->caseTranslate[i] = i;
	for (j = 'a'; j <= 'z'; j++)
	   stream->state->caseTranslate[j] = j - ('a' - 'A');

	return R_OK;
}


/* rlibCompile: ----------------------------------------------------
 *  Compile a script
 */
int rlibCompile(r_script* script, const char* data)
{
	return compilerRun(script, data);
}


/* rlibClear: -------------------------------------------------------------
 *  Prepare stream for a new file
 */
void rlibClear(r_stream* stream)
{
	if(stream)
	{
		if(stream->state)
			vmClean(stream);
	}
}



/* rLibRun: ---------------------------------------------------------------
 *  The replacement coordinator, output etc...
*/
int rlibRun(r_stream* stream, r_script* script, int done)
{
	#define RETURN(r) do { retv = r; goto finally; } while(0)

	struct internal_state* state = stream->state;
	size_t backup, curOffset;
	int retv = R_OK;

	if(!stream->state)
		return R_INVARG;

	/* Usually have to have an output function, unless just a matcher */
	if(!stream->fWrite && !(state->options & RLIB_MODE_MATCHER))
		return R_INVARG;
	/* And if we are a matcher we have to have a match function */
	if(state->options & RLIB_MODE_MATCHER && !stream->fMatch)
		return R_INVARG;


	/*
	 * Keep at least 1/2 amount of backup
	 * Backup is only kept if no matches occur in backup area
	 */
	backup = done ? 0 : stream->availIn / 2;

	/*
	 * Since there are conversions (between absolute and relative offsets)
	 * below, we need to keep inOffset the same for this session. So copy
	 * it and update it again at the end of the function.
	 */
	curOffset = 0;

	/*  Need some data to work with */
	if(!stream->nextIn || !stream->availIn)
		RETURN(R_IN);


	stream->total = 0;

	/* Execute the script */
	retv = vmExecute(stream, script);

	/* Error? */
	if(retv < 0)
		RETURN(retv);

	/* Fall through to commit code */
	if(retv == R_DONE)
		backup = 0;

	if(!(state->options & RLIB_MODE_MATCHER))
	{
		/*
		 * Here we write out what we've found so far and advance the
		 * pointers
		 *
		 * On the first round we look something like this
		 *
		 *               <- state->searched ->
		 *   |---------------------------------------------|    <-  stream->nextIn
		 *   |----------------------------------------|		   <-  stream->nextOut
		 *                replacements found             ^- leftovers
		 */

		/* toWrite is the size of the current block we need to transfer */
		size_t toWrite;
		/* block is the amount we can actually transfer (depending on output buffer) */
		size_t block = stream->availIn;

#ifdef VERBOSE
		dumpRelpacements(stream);
#endif

		while(state->replaces)
		{
			/* Get the amount of data till the current replace */
			toWrite = block = ABS_TO_REL(state->replaces->beg, state) - curOffset;

			if(!(state->options & RLIB_MODE_PARSER))
			{
				/* ... write out up to current replacement... */
				if(!(stream->fWrite)(stream, stream->nextIn, block))
					RETURN(R_IOERR);
			}

			stream->nextIn += block;
			stream->availIn -= block;
			curOffset += block;


			/* ... check space for replacement ... */
			block = strlen(state->replaces->text);

			/* ...write out replacement... */
			if(!(stream->fWrite)(stream, (byte*)state->replaces->text, block))
				RETURN(R_IOERR);

			/* ... and skip (!) the text that we replaced */
			block = state->replaces->end - state->replaces->beg;
			stream->nextIn += block;
			stream->availIn -= block;
			curOffset += block;

#ifdef _DEBUG
			/* Check if things are in the right order */
			if(state->replaces->next)
				ASSERT(state->replaces->end <= state->replaces->next->end);
#endif
			/* Go to the next replacement */
			state->replaces = replacementPop(state->replaces);
		}

		/*
		 * Now we check how much data we have left and copy
		 * up to backup if we have more
		 */

		/* Copy out till backup marker */
		if((stream->availIn) >= backup)
		{
			/* Get block size ... */
			toWrite = block = stream->availIn - backup;

			if(!(state->options & RLIB_MODE_PARSER))
			{
				if(!(stream->fWrite)(stream, stream->nextIn, block))
					RETURN(R_IOERR);
			}

			stream->nextIn += block;
			stream->availIn -= block;
			curOffset += block;
		}
	}

	/*
	 * After this the search could start anew
	 * unless in flush mode or done
	 */
	if(done == true)
		RETURN(R_DONE);
	else
		RETURN(R_IN);

finally:
	state->offset += curOffset;

	return retv;
}


/* rlibSetVar: -----------------------------------------------------------
 *  Set a variable for the script to use
 */
int rlibSetVar(r_stream* stream, const char* var, const char* val)
{
	if(!stream || !stream->state || !var || !val)
		return R_INVARG;

	variablesClear(&(stream->state->vars), var);
	return variablesAdd(&(stream->state->vars), var, val) ? R_OK : R_NOMEM;
}


/* rlibDump: --------------------------------------------------------------
 *  Dump the rep script opts for debugging
 */
void rlibDump(r_script* script, FILE* f)
{
	opsDump(script->ops, f);
}


/* rlibFree: --------------------------------------------------------------
 *  Free associated structures data etc...
 */
void rlibFree(r_stream* stream, r_script* script)
{
	struct internal_state* state;

	if(stream)
	{
		if(state = stream->state)
		{
			/* Let execution free it's stuff */
			vmFree(stream);

			/* And free the state */
			free(state);
			stream->state = NULL;
		}

		zero(*stream);
	}

	if(script)
	{
		if(script->ops)
			free(script->ops);

		if(script->error)
			free(script->error);

		zero(*script);
	}

}


/* scriptSetError: -------------------------------------------------
 *  Set the stream error text to whatever
 */
void scriptSetError(r_script* script, const char* format, ...)
{
	char* msg;

	va_list vl;
	va_start(vl, format);

	if(script->error)
		free(script->error);

	if(vasprintf(&msg, format, vl) != -1)
		script->error = msg;
	else
		script->error = NULL;

	va_end(vl);
}

/* compileAlready: ------------------------------------------------------
 *  See if the file has already been compiled and load if so
 */
int compileAlready(r_context* ctx, FILE* file)
{
	/* Should have already read header */
	bfval val;
	BFILE h = NULL;
	int retv = R_OK;
	r_uint temp;

	if(!(h = bfStartFile(file)))
		RETURN(R_INVARG);

	if(!repfReadHeader(h))
		RETURN(R_IN);

	while(bfReadValueInfo(h, &val))
	{
		if(ferror(file))
			RETURN(R_IOERR);

		if(feof(file))
			RETURN(R_INVARG);

		switch(val.id)
		{
		case REPVAL_BUFSIZE:
			if(ctx->block == 0)
				bfReadValueData(h, &val, &(ctx->block));
			continue;

		case REPVAL_PARSEMODE:
			if(bfReadValueData(h, &val, &temp))
				ctx->options |= (temp != 0) ? RLIB_MODE_PARSER : 0;
			continue;

		case REPVAL_SCRIPT:
			{
				ctx->script.ops = (r_byte*)malloc(val.len);
				if(!ctx->script.ops)
					RETURN(R_NOMEM);

				bfReadValueData(h, &val, ctx->script.ops);
				ctx->script.len = val.len;
				continue;
			}
			break;
		}

		bfSkipValueData(h, &val);
	}

finally:
	if(h)
		bfClose(h);

	return retv;
}


int repLoad(r_context* ctx, FILE* f)
{
	int retv = R_OK;
	char* buff = NULL;
	size_t len;
	int r;

	rlibFree(NULL, &(ctx->script));

	/* Okay now try and read header, and possibly process
	   an already executable file. */
	switch(r = compileAlready(ctx, f))
	{
	/* It's already compiled */
	case R_OK:
		RETURN(R_OK);
		break;

	/* It's not compiled so compile */
	case R_IN:
		break;

	/* Failed processing */
	default:
		if(r < 0)
			RETURN(r);
		break;
	};

	/* Get file size */
	len = 0;

	if(fseek(f, 0, SEEK_END) || !(len = ftell(f)) ||
	   fseek(f, 0, SEEK_SET))
		RETURN(R_IOERR);

	buff = (char*)malloc(len + 1);
	if(!buff)
		RETURN(R_NOMEM);

	if(fread(buff, 1, len, f) != len)
		RETURN(R_IOERR);

	/* Needs compiling */
	buff[len] = '\0';

	/* Init the stream */
	r = rlibCompile(&(ctx->script), buff);
	if(r < 0)
		RETURN(r);

finally:
	if(buff)
		free(buff);

	return retv;
}

int repInit(r_context* ctx)
{
	rlibInit(&(ctx->stream), ctx->options);
	return R_OK;
}

int repFile(r_context* ctx, FILE* fIn)
{
	r_uint batch;				/*  Current batch size */
	r_uint block = ctx->block;	/*  Block size */
	r_byte* buff = NULL;		/*  Input buffer */
	int retv = R_OK;
	int r = R_IN;
	int total = 0;

	if(!block)
	{
		if(!fseek(fIn, 0, SEEK_END) && (block = ftell(fIn)) != ~0)
			block++;

		else
			block = 0;

		fseek(fIn, 0, SEEK_SET);
	}

	else
	{
		block *= 2;
	}

	/* Okay now if it's a sane value just allocate it */
	if(block)
	{
		if(block > 0x0F00000)
			RETURN(R_NOMEM);

		/* Allocate buffers */
		buff = (r_byte*)malloc(block);
		if(!buff)
			RETURN(R_NOMEM);
	}

	/*  Hook buffers to the stream */
	ctx->stream.nextIn = buff;
	ctx->stream.availIn = 0;

	/*  While we either have more data to put in or more output... */
	while(!feof(fIn) || r == R_DONE)
	{
		/*  If rlib wants data then give it */
		if(r == R_IN)
		{
			/* This is a normal standard read */
			if(buff)
			{
				/*  Move data to front */
				memmove(buff, ctx->stream.nextIn, ctx->stream.availIn);

				/*  Set pointer to data */
				ctx->stream.nextIn = buff;

				/*  Read rest of block */
				batch = fread(ctx->stream.nextIn + ctx->stream.availIn,
						      sizeof(r_byte), block - ctx->stream.availIn, fIn);

				ctx->stream.availIn += batch;

				if(ferror(fIn))
					RETURN(R_IOERR);
			}

			/* Here we read as much as possible in one shot allocating as we go*/
			else
			{
				batch = 0;
				block = 0;

				while(!feof(fIn))
				{
					if(ferror(fIn))
						RETURN(R_IOERR);

					block += 0x4000;

					if(block > MAX_BUFF ||
					   !(buff = reallocf(buff, block)))
						RETURN(R_NOMEM);

					batch += fread(buff + batch, sizeof(r_byte),
						           0x4000, fIn);
				}

				ctx->stream.nextIn = buff;
				ctx->stream.availIn += batch;
			}
		}

		/*  call rlib */
		r = rlibRun(&(ctx->stream), &(ctx->script), feof(fIn));

		// Oops!
		if(r < 0)
			RETURN(r);

		total += ctx->stream.total;
	}

finally:
	if(buff)
		free(buff);

	ctx->stream.total = total;

	return retv;
}

int fileOutput(struct r_stream* stream, byte* data, size_t len)
{
	FILE* f = (FILE*)stream->arg;
	return (fwrite(data, 1, len, f) == len) && (!ferror(f));
}

int repFiles(r_context* ctx, FILE* fIn, FILE* fOut)
{
	void* arg = ctx->stream.arg;
	r_write func = ctx->stream.fWrite;
	int ret;

	ctx->stream.fWrite = fileOutput;
	ctx->stream.arg = fOut;

	ret = repFile(ctx, fIn);

	ctx->stream.fWrite = func;
	ctx->stream.arg = arg;

	return ret;
}

void repFree(r_context* ctx)
{
	rlibFree(&(ctx->stream), &(ctx->script));
}