/**************************************************************/
/*  treebnf: a tree oriented bnf library                      */
/*  Copyright (C) 2024  SysDeer Technologies, LLC             */
/*  Released under GPLv2 and GPLv3; see COPYING.TREEBNF.      */
/**************************************************************/

#include <stdint.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>

#include <treebnf/treebnf.h>
#include "treebnf_driver_impl.h"
#include "treebnf_errinfo_impl.h"
#include "treebnf_tmpfile_impl.h"

static int tbnf_free_unit_ctx_impl(struct tbnf_unit_ctx_impl * ctx, int ret)
{
	if (ctx) {
		tbnf_lib_unmap_raw_input(&ctx->map);
		free(ctx);
	}

	return ret;
}

static int tbnf_stdin_to_tmp(const struct tbnf_driver_ctx * dctx)
{
	struct tbnf_driver_ctx_impl *	ictx;
	int				fdtmp;

	ssize_t ret;
	ssize_t cnt;
	char *	ch;
	char	buf[4096];

	ictx = tbnf_get_driver_ictx(dctx);

	if (ictx->fdtmpin >= 0)
		return dup(ictx->fdtmpin);

	if ((fdtmp = tbnf_tmpfile()) < 0)
		return -1;

	if ((ictx->fdtmpin = dup(fdtmp)) < 0) {
		close(fdtmp);
		return -1;
	}

	for (;;) {
		ret = read(0,buf,sizeof(buf)-1);

		while ((ret < 0) && (errno == EINTR))
			ret = read(0,buf,sizeof(buf)-1);

		if (ret < 0) {
			close(fdtmp);
			return -1;

		} else if (ret == 0) {
			return fdtmp;

		} else {
			ch  = buf;
			cnt = ret;

			for (; cnt; ) {
				ret = write(fdtmp,ch,cnt);

				while ((ret < 0) && (errno == EINTR))
					ret = write(fdtmp,ch,cnt);

				if (ret < 0) {
					close(fdtmp);
					return -1;
				}

				ch  += ret;
				cnt -= ret;
			}
		}
	}
}

int tbnf_lib_get_unit_ctx(
	const struct tbnf_driver_ctx *	dctx,
	const char *			path,
	struct tbnf_unit_ctx **		pctx)
{
	struct tbnf_unit_ctx_impl *	ctx;
	int				prot;
	int                             fd;

	if (!dctx)
		return TBNF_CUSTOM_ERROR(
			dctx,TBNF_ERR_NULL_CONTEXT);

	else if (!(ctx = calloc(1,sizeof(*ctx))))
		return TBNF_BUFFER_ERROR(dctx);

	tbnf_driver_set_ectx(
		dctx,0,path);

	prot = PROT_READ;

	if (strcmp(path,"-"))
		fd = -1;

	else if ((fd = tbnf_stdin_to_tmp(dctx)) < 0)
		return tbnf_free_unit_ctx_impl(
			ctx,TBNF_FILE_ERROR(dctx));

	if (tbnf_lib_map_raw_input(dctx,fd,path,prot,&ctx->map))
		return tbnf_free_unit_ctx_impl(
			ctx,TBNF_NESTED_ERROR(dctx));

	if (fd >= 0)
		close(fd);

	ctx->path	= path;
	ctx->uctx.path	= &ctx->path;
	ctx->uctx.map	= &ctx->map;

	*pctx = &ctx->uctx;
	return 0;
}

void tbnf_lib_free_unit_ctx(struct tbnf_unit_ctx * ctx)
{
	struct tbnf_unit_ctx_impl *	ictx;
	uintptr_t			addr;

	if (ctx) {
		addr = (uintptr_t)ctx - offsetof(struct tbnf_unit_ctx_impl,uctx);
		ictx = (struct tbnf_unit_ctx_impl *)addr;
		tbnf_free_unit_ctx_impl(ictx,0);
	}
}