/****************************************************************************/

/*  argv.h: a thread-safe argument vector parser and usage screen generator */

/*  Copyright (C) 2015  Z. Gilboa                                           */

/*  Released under GPLv2 and GPLv3; see COPYING.PERK.                       */

/*  This file is (also) part of sofort: portable software project template. */

/****************************************************************************/

#ifndef ARGV_H

#define ARGV_H

#include <stdbool.h>

#include <stdint.h>

#include <stddef.h>

#include <errno.h>

#include <string.h>

#include <stdlib.h>

#include <stdio.h>

#define ARGV_VERBOSITY_NONE		0x00

#define ARGV_VERBOSITY_ERRORS		0x01

#define ARGV_VERBOSITY_STATUS		0x02

#define ARGV_CLONE_VECTOR		0x80

enum argv_optarg {

	ARGV_OPTARG_NONE,

	ARGV_OPTARG_REQUIRED,

	ARGV_OPTARG_OPTIONAL,

};

enum argv_mode {

	ARGV_MODE_SCAN,

	ARGV_MODE_COPY,

};

enum argv_error {

	ARGV_ERROR_OK,

	ARGV_ERROR_INTERNAL,

	ARGV_ERROR_SHORT_OPTION,

	ARGV_ERROR_LONG_OPTION,

	ARGV_ERROR_OPTARG_NONE,

	ARGV_ERROR_OPTARG_REQUIRED,

	ARGV_ERROR_OPTARG_PARADIGM,

};

struct argv_option {

	const char *		long_name;

	const char		short_name;

	int			tag;

	enum argv_optarg	optarg;

	const char *		paradigm;

	const char *		argname;

	const char *		description;

};

struct argv_entry {

	const char *	arg;

	int		tag;

	bool		fopt;

	bool		fval;

	bool		fnoscan;

	enum argv_error errcode;

};

struct argv_meta {

	const char **		argv;

	struct argv_entry *	entries;

};

struct argv_meta_impl {

	const char **		argv;

	char *			strbuf;

	struct argv_meta	meta;

};

struct argv_ctx {

	int				flags;

	int				mode;

	int				nentries;

	enum argv_error 		errcode;

	const char *			errch;

	const struct argv_option *	erropt;

	const char *			program;

};

static const char * argv_program_name(const char *);

static void argv_usage(

	FILE *,

	const char *	header,

	const struct	argv_option[],

	const char *	mode);

static struct argv_meta * argv_get(

	const char **,

	const struct argv_option[],

	int flags);

static void argv_free(struct argv_meta *);

/*------------------------------------*/

/* implementation of static functions */

/*------------------------------------*/

#ifdef ARGV_DRIVER

static const struct argv_option * argv_short_option(

	const char *			ch,

	const struct argv_option	options[],

	struct argv_entry *		entry)

{

	const struct argv_option *	option;

	for (option=options; option->long_name || option->short_name; option++) {

		if (option->short_name == *ch) {

			entry->tag	= option->tag;

			entry->fopt	= true;

			return option;

		}

	}

	return 0;

}

static const struct argv_option * argv_long_option(

	const char *			ch,

	const struct argv_option	options[],

	struct argv_entry *		entry)

{

	const struct argv_option *	option;

	const char *			arg;

	size_t				len;

	for (option=options; option->long_name || option->short_name; option++) {

		len = option->long_name ? strlen(option->long_name) : 0;

		if (len && !(strncmp(option->long_name,ch,len))) {

			arg = ch + len;

			if (!*arg || (*arg == '=')) {

				entry->tag	= option->tag;

				entry->fopt	= true;

				return option;

			}

		}

	}

	return 0;

}

static inline bool is_short_option(const char * arg)

{

	return (arg[0]=='-') && arg[1] && (arg[1]!='-');

}

static inline bool is_long_option(const char * arg)

{

	return (arg[0]=='-') && (arg[1]=='-') && arg[2];

}

static inline bool is_last_option(const char * arg)

{

	return (arg[0]=='-') && (arg[1]=='-') && !arg[2];

}

static inline bool is_arg_in_paradigm(const char * arg, const char * paradigm)

{

	size_t		len;

	const char *	ch;

	for (ch=paradigm,len=strlen(arg); ch; ) {

		if (!strncmp(arg,ch,len)) {

			if (!*(ch += len))

				return true;

			else if (*ch == '|')

				return true;

		}

		if ((ch = strchr(ch,'|')))

			ch++;

	}

	return false;

}

static inline const struct argv_option * option_from_tag(

	const struct argv_option	options[],

	int				tag)

{

	const struct argv_option *	option;

	for (option=options; option->short_name || option->long_name; option++)

		if (option->tag == tag)

			return option;

	return 0;

}

static void argv_scan(

	const char **			argv,

	const struct argv_option	options[],

	struct argv_ctx *		ctx,

	struct argv_meta *		meta)

{

	const char **			parg;

	const char *			ch;

	const char *			val;

	const struct argv_option *	option;

	struct argv_entry		entry;

	struct argv_entry *		mentry;

	enum argv_error			ferror;

	bool				fval;

	bool				fnext;

	bool				fshort;

	bool				fnoscan;

	argv++;

	parg	= argv;

	ch	= *parg;

	ferror	= ARGV_ERROR_OK;

	fshort	= false;

	fnoscan	= false;

	fval	= false;

	mentry	= meta ? meta->entries : 0;

	while (ch && (ferror == ARGV_ERROR_OK)) {

		option = 0;

		if (fnoscan)

			fval = true;

		else if (is_last_option(ch))

			fnoscan = true;

		else if ((fshort || is_short_option(ch))) {

			if (!fshort)

				ch++;

			if ((option = argv_short_option(ch,options,&entry))) {

				if (ch[1]) {

					ch++;

					fnext	= false;

					fshort	= (option->optarg == ARGV_OPTARG_NONE);

				} else {

					parg++;

					ch	= *parg;

					fnext	= true;

					fshort	= false;

				}

				if (option->optarg == ARGV_OPTARG_NONE) {

					if (!fnext && ch && (*ch == '-'))

						ferror = ARGV_ERROR_OPTARG_NONE;

					else

						fval = false;

				} else if (!fnext)

					fval = true;

				else if (option->optarg == ARGV_OPTARG_REQUIRED) {

					if (ch && is_short_option(ch))

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else if (ch && is_long_option(ch))

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else if (ch && is_last_option(ch))

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else if (ch)

						fval = true;

					else

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

				} else {

					/* ARGV_OPTARG_OPTIONAL */

					if (ch && is_short_option(ch))

						fval = false;

					else if (ch && is_long_option(ch))

						fval = false;

					else if (ch && is_last_option(ch))

						fval = false;

					else

						fval = ch;

				}

			} else

				ferror = ARGV_ERROR_SHORT_OPTION;

		} else if ((is_long_option(ch))) {

			if ((option = argv_long_option(ch+=2,options,&entry))) {

				val = ch + strlen(option->long_name);

				/* val[0] is either '=' or '\0' */

				if (!val[0]) {

					parg++;

					ch = *parg;

				}

				if (option->optarg == ARGV_OPTARG_NONE) {

					if (val[0]) {

						ferror = ARGV_ERROR_OPTARG_NONE;

						ctx->errch = val + 1;

					} else

						fval = false;

				} else if (val[0] && !val[1])

					ferror = ARGV_ERROR_OPTARG_REQUIRED;

				else if (val[0] && val[1]) {

					fval = true;

					ch   = ++val;

				} else if (option->optarg == ARGV_OPTARG_REQUIRED) {

					if (!val[0] && !*parg)

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else if (*parg && is_short_option(*parg))

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else if (*parg && is_long_option(*parg))

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else if (*parg && is_last_option(*parg))

						ferror = ARGV_ERROR_OPTARG_REQUIRED;

					else

						fval = true;

				} else {

					/* ARGV_OPTARG_OPTIONAL */

					if (!val[0] && !*parg)

						fval = false;

					if (*parg && is_short_option(*parg))

						fval = false;

					else if (*parg && is_long_option(*parg))

						fval = false;

					else if (*parg && is_last_option(*parg))

						fval = false;

					else

						fval = *parg;

				}

			} else

				ferror = ARGV_ERROR_LONG_OPTION;

		}

		if (ferror == ARGV_ERROR_OK)

			if (option && fval && option->paradigm)

				if (!is_arg_in_paradigm(ch,option->paradigm))

					ferror = ARGV_ERROR_OPTARG_PARADIGM;

		if (ferror != ARGV_ERROR_OK) {

			ctx->errcode = ferror;

			ctx->errch   = ctx->errch ? ctx->errch : ch;

			ctx->erropt  = option;

			return;

		} else if (ctx->mode == ARGV_MODE_SCAN) {

			if (!fnoscan)

				ctx->nentries++;

			else if (fval)

				ctx->nentries++;

			if (fval || !option) {

				parg++;

				ch = *parg;

			}

		} else if (ctx->mode == ARGV_MODE_COPY) {

			if (fnoscan) {

				if (fval) {

					mentry->arg	= ch;

					mentry->fnoscan = true;

					mentry++;

				}

				parg++;

				ch = *parg;

			} else if (option) {

				mentry->arg	= fval ? ch : 0;

				mentry->tag	= option->tag;

				mentry->fopt	= true;

				mentry->fval	= fval;

				mentry++;

				if (fval) {

					parg++;

					ch = *parg;

				}

			} else {

				mentry->arg = ch;

				mentry++;

				parg++;

				ch = *parg;

			}

		}

	}

}

static const char * argv_program_name(const char * program_path)

{

	const char * ch;

	if (program_path) {

		if ((ch = strrchr(program_path,'/')))

			return *(++ch) ? ch : 0;

		if ((ch = strrchr(program_path,'\\')))

			return *(++ch) ? ch : 0;

	}

	return program_path;

}

static void argv_show_error(struct argv_ctx * ctx)

{

	fprintf(stderr,"%s: error: ",ctx->program);

	switch (ctx->errcode) {

		case ARGV_ERROR_SHORT_OPTION:

			fprintf(stderr,"'%c' is not a valid short option\n",*ctx->errch);

			break;

		case ARGV_ERROR_LONG_OPTION:

			fprintf(stderr,"'--%s' is not a valid long option\n",ctx->errch);

			break;

		case ARGV_ERROR_OPTARG_NONE:

			fprintf(stderr,"'%s' is not a valid option value for [%s%c%s%s%s] (option values may not be specified)\n",

				ctx->errch,

				ctx->erropt->short_name ? "-" : "",

				ctx->erropt->short_name,

				ctx->erropt->short_name ? "," : "",

				ctx->erropt->long_name ? "--" : "",

				ctx->erropt->long_name);

			break;

		case ARGV_ERROR_OPTARG_REQUIRED:

			fprintf(stderr,"option [%s%c%s%s%s] requires %s %s%s%s\n",

				ctx->erropt->short_name ? "-" : "",

				ctx->erropt->short_name,

				ctx->erropt->short_name ? "," : "",

				ctx->erropt->long_name ? "--" : "",

				ctx->erropt->long_name,

				ctx->erropt->paradigm ? "one of the following values:" : "a value",

				ctx->erropt->paradigm ? "{" : "",

				ctx->erropt->paradigm ? ctx->erropt->paradigm : "",

				ctx->erropt->paradigm ? "}" : "");

			break;

		case ARGV_ERROR_OPTARG_PARADIGM:

			fprintf(stderr,"'%s' is not a valid option value for [%s%c%s%s%s]={%s}\n",

				ctx->errch,

				ctx->erropt->short_name ? "-" : "",

				ctx->erropt->short_name,

				ctx->erropt->short_name ? "," : "",

				ctx->erropt->long_name ? "--" : "",

				ctx->erropt->long_name,

				ctx->erropt->paradigm);

			break;

		case ARGV_ERROR_INTERNAL:

			fputs("internal error",stderr);

			break;

		default:

			break;

	}

}

static void argv_show_status(

	const struct argv_option	options[],

	struct argv_ctx *		ctx,

	struct argv_meta *		meta)

{

	int				argc;

	const char **			argv;

	struct argv_entry *		entry;

	const struct argv_option *	option;

	char				short_name[2] = {0};

	const char *			space = "";

	fputs("\n\nconcatenated command line:\n",stderr);

	for (argv=meta->argv; *argv; argv++) {

		fprintf(stderr,"%s%s",space,*argv);

		space = " ";

	}

	fputs("\n\nargument vector:\n",stderr);

	for (argc=0,argv=meta->argv; *argv; argc++,argv++)

		fprintf(stderr,"argv[%d]: %s\n",argc,*argv);

	fputs("\n\nparsed entries:\n",stderr);

	for (entry=meta->entries; entry->arg || entry->fopt; entry++)

		if (entry->fopt) {

			option = option_from_tag(options,entry->tag);

			short_name[0] = option->short_name;

			if (entry->fval)

				fprintf(stderr,"[-%s,--%s] := %s\n",

					short_name,option->long_name,entry->arg);

			else

				fprintf(stderr,"[-%s,--%s]\n",

					short_name,option->long_name);

		} else

			fprintf(stderr,"<program arg> := %s\n",entry->arg);

	fputs("\n\n",stderr);

}

static struct argv_meta * argv_free_impl(struct argv_meta_impl * imeta)

{

	if (imeta->argv)

		free(imeta->argv);

	if (imeta->strbuf)

		free(imeta->strbuf);

	if (imeta->meta.entries)

		free(imeta->meta.entries);

	free(imeta);

	return 0;

}

static struct argv_meta * argv_alloc(const char ** argv, struct argv_ctx * ctx)

{

	struct argv_meta_impl * imeta;

	const char **		vector;

	char *			dst;

	size_t			size;

	int			argc;

	int			i;

	if (!(imeta = calloc(sizeof(*imeta),1)))

		return 0;

	if (ctx->flags & ARGV_CLONE_VECTOR) {

		for (vector=argv,argc=0,size=0; *vector; vector++) {

			size += strlen(*vector) + 1;

			argc++;

		}

		if (!(imeta->argv = calloc(sizeof(char *),argc+1)))

			return argv_free_impl(imeta);

		else if (!(imeta->strbuf = calloc(size+1,1)))

			return argv_free_impl(imeta);

		for (i=0,dst=imeta->strbuf; i

			strcpy(dst,argv[i]);

			imeta->argv[i] = dst;

			dst += strlen(dst)+1;

		}

		imeta->meta.argv = imeta->argv;

	} else

		imeta->meta.argv = argv;

	if (!(imeta->meta.entries = calloc(sizeof(struct argv_entry),ctx->nentries+1)))

		return argv_free_impl(imeta);

	else

		return &imeta->meta;

}

static struct argv_meta * argv_get(

	const char *			argv[],

	const struct argv_option	options[],

	int				flags)

{

	struct argv_meta *	meta;

	struct argv_ctx		ctx = {flags,ARGV_MODE_SCAN,0,0,0,0};

	argv_scan(argv,options,&ctx,0);

	if (ctx.errcode != ARGV_ERROR_OK) {

		if (!ctx.program)

			ctx.program = argv_program_name(argv[0]);

		if (ctx.flags & ARGV_VERBOSITY_ERRORS)

			argv_show_error(&ctx;;

		return 0;

	}

	if (!(meta = argv_alloc(argv,&ctx)))

		return 0;

	ctx.mode = ARGV_MODE_COPY;

	argv_scan(meta->argv,options,&ctx,meta);

	if (ctx.errcode != ARGV_ERROR_OK) {

		if (!ctx.program)

			ctx.program = argv[0];

		ctx.errcode = ARGV_ERROR_INTERNAL;

		argv_show_error(&ctx;;

		argv_free(meta);

		return 0;

	}

	if (ctx.flags & ARGV_VERBOSITY_STATUS)

		argv_show_status(options,&ctx,meta);

	return meta;

}

static void argv_free(struct argv_meta * xmeta)

{

	struct argv_meta_impl * imeta;

	uintptr_t		addr;

	if (xmeta) {

		addr  = (uintptr_t)xmeta - offsetof(struct argv_meta_impl,meta);

		imeta = (struct argv_meta_impl *)addr;

		argv_free_impl(imeta);

	}

}

static void argv_usage(

	FILE *				file,

	const char *    		header,

	const struct argv_option	options[],

	const char *			mode)

{

	const struct argv_option *	option;

	bool				fshort,flong;

	bool				fnewline;

	size_t				len,optlen;

	size_t				paralen,rparalen,mparalen;

	size_t				desclen,rdesclen;

	char *				para;

	char *				next_para;

	char *				desc;

	char *				next_desc;

	char *				paradigm;

	char *				buf;

	size_t				buflen;

	const char *			sdescription;

	const char *			sargname;

	const char			indent[] = "  ";

	const int			rblen  = sizeof("}") - sizeof(char);

	const int			rbblen = sizeof("{]") - sizeof(char);

	const int			brcklen= sizeof("[]") - sizeof(char);

	const int			solen  = sizeof("-") - sizeof(char);

	const int			lolen  = sizeof("--") - sizeof(char);

	const int			slolen = sizeof("-X,--") - sizeof(char);

	fshort = mode ? !strcmp(mode,"short") : 0;

	flong  = fshort ? 0 : mode && !strcmp(mode,"long");

	if (header)

		fprintf(stdout,"%s",header);

	for (option=options,optlen=0,paralen=0; option->short_name || option->long_name; option++) {

		if (fshort)

			len = option->short_name ? sizeof(char) + solen : 0;

		else if (flong)

			len = option->long_name ? strlen(option->long_name) + lolen : 0;

		else

			len = option->long_name ? strlen(option->long_name) + slolen : 0;

		if (len) {

			if (len > optlen)

				optlen = len;

			if (option->paradigm)

				len = strlen(option->paradigm) + strlen("{}");

			else if (option->argname)

				len = strlen(option->argname);

			else if (option->optarg != ARGV_OPTARG_NONE)

				len = strlen("<val>");

			if (option->optarg == ARGV_OPTARG_OPTIONAL)

				len += strlen("[]");

			if (len > paralen)

				paralen = len;

		}

	}

	optlen += 8;

	optlen &= (~7);

	if (paralen) {

		paralen += (8);

		paralen &= (~7);

		mparalen = paralen + 2*rbblen;

		if (optlen + paralen > 64)

			paralen = 32;

	}

	/* account for '  ','\t', try to fit in 80 or 96 columns */

	if (optlen+paralen+2+8 < 80-32)

		desclen = 80 - (optlen+paralen+2+8);

	else if (optlen+paralen+2+8 < 96-32)

		desclen = 96 - (optlen+paralen+2+8);

	else

		desclen = 32;

	paradigm = next_para = buf = 0;

	fnewline = false;

	rparalen = 0;

	mparalen = 0;

	for (option=options,buflen=0,rdesclen=1; option->short_name || option->long_name; option++) {

		if (option->paradigm) {

			if (option->optarg == ARGV_OPTARG_OPTIONAL)

				rparalen = strlen(option->paradigm) - 2*rbblen;

			else

				rparalen = strlen(option->paradigm) - 2*rblen;

		}

		sdescription 	= option->description ? option->description : "";

		sargname	= option->argname ? option->argname : "";

		if (option->paradigm)

			rdesclen = snprintf(buf,buflen,sdescription,option->paradigm);

		else

			rdesclen = snprintf(buf,buflen,sdescription,sargname);

		if (fnewline)

			(void)0;

		if ((rparalen > paralen) || (rdesclen > desclen)) {

			if (!fnewline) {

				(void)0;

				fnewline = true;

			}

		} else

			fnewline = false;