/*********************************************************************
 *   Copyright 2010, UCAR/Unidata
 *   See netcdf/COPYRIGHT file for copying and redistribution conditions.
 *   $Header$
 *********************************************************************/

#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "nc_uri.h"

#define NC_URIDEBUG

#define LBRACKET '['
#define RBRACKET ']'

#ifndef FIX
#define FIX(s) ((s)==NULL?"":(s))
#endif

#ifndef NILLEN
#define NILLEN(s) ((s)==NULL?0:strlen(s))
#endif


static char* legalprotocols[] = {
"file:",
"http:",
"https:",
"ftp:",
NULL /* NULL terminate*/
};

static void nc_paramfree(char** params);
static int nc_find(char** params, const char* key);

/* Do a simple uri parse: return 0 if fail, 1 otherwise*/
int
nc_uriparse(const char* uri0, NC_URI** nc_urip)
{
    NC_URI* nc_uri = NULL;
    char* uri;
    char** pp;
    char* p;
    char* p1;
    int c;

    /* accumulate parse points*/
    char* protocol = NULL;
    char* params = NULL;
    char* host = NULL;
    char* port = NULL;
    char* constraint = NULL;
    char* user = NULL;
    char* pwd = NULL;
    char* file = NULL;

    nc_uri = (NC_URI*)calloc(1,sizeof(NC_URI));
    if(nc_uri == NULL) return 0;    

    /* Temporary hack to remove escape characters inserted by Windows or MinGW */
    if(strchr(uri0,'\\') != NULL) {    
	char* u = strdup(uri0);
	if(u == NULL) return 0;
        p = u;
	p1 = u;
        while((c=*p1++)) {if(c != '\\') *p++ = c;}
	uri0 = (const char*)u;
    }

    /* make local copy of uri */
    uri = strdup(uri0);

    /* remove all whitespace*/
    p = uri;
    p1 = uri;
    while((c=*p1++)) {if(c != ' ' && c != '\t') *p++ = c;}

    p = uri;

    /* break up the uri string into pieces*/

    /* 1. leading bracketed parameters */
    if(*p == LBRACKET) {
	params = p+1;
	/* find end of the clientparams*/
        for(;*p;p++) {if(p[0] == RBRACKET && p[1] != LBRACKET) break;}
	if(*p == 0) goto fail; /* malformed client params*/
	*p = '\0'; /* leave off the trailing rbracket for now */
	p++; /* move past the params*/
    }

    /* verify that the uri starts with an acceptable protocol*/
    for(pp=legalprotocols;*pp;pp++) {
        if(strncmp(p,*pp,strlen(*pp))==0) break;
    }
    if(*pp == NULL) goto fail; /* illegal protocol*/
    /* save the protocol */
    protocol = *pp;

    /* 4. skip protocol */
    p += strlen(protocol);

    /* 5. skip // */
    if(*p != '/' && *(p+1) != '/')
	goto fail;
    p += 2;

    /* 6. Mark the end of the host section */
    file = strchr(p,'/');
    if(file) {
	*file++ = '\0'; /* warning: we just overwrote the leading / */
    } else
	goto fail; /* url only has host part, no path */

    /* 7. extract any user:pwd */
    p1 = strchr(p,'@');
    if(p1) {/* Assume we have user:pwd@ */
	*p1 = '\0';
	user = p;
	pwd = strchr(p,':');
	if(!pwd) goto fail; /* malformed */
	*pwd++ = '\0';
	p = pwd+strlen(pwd)+1;
    }

    /* 8. extract host and port */
    host = p;
    port = strchr(p,':');
    if(port) {
	*port++ = '\0';
    }

    /* 9. Look for '?' */
    constraint = strchr(file,'?');
    if(constraint) {
	*constraint++ = '\0';
    }

    /* assemble the component pieces*/
    if(uri0 && strlen(uri0) > 0)
        nc_uri->uri = strdup(uri0);
    if(protocol && strlen(protocol) > 0) {
        nc_uri->protocol = strdup(protocol);
        /* remove trailing ':' */
        nc_uri->protocol[strlen(protocol)-1] = '\0';
    }
    if(user && strlen(user) > 0)
        nc_uri->user = strdup(user);
    if(pwd && strlen(pwd) > 0)
        nc_uri->password = strdup(pwd);
    if(host && strlen(host) > 0)
        nc_uri->host = strdup(host);
    if(port && strlen(port) > 0)
        nc_uri->port = strdup(port);
    if(file && strlen(file) > 0) {
	/* Add back the leading / */
        nc_uri->file = malloc(strlen(file)+2);
	strcpy(nc_uri->file,"/");
        strcat(nc_uri->file,file);
    }
    if(constraint && strlen(constraint) > 0)
        nc_uri->constraint = strdup(constraint);
    nc_urisetconstraints(nc_uri,constraint);
    if(params != NULL && strlen(params) > 0) {
        nc_uri->params = (char*)malloc(1+2+strlen(params));
        strcpy(nc_uri->params,"[");
        strcat(nc_uri->params,params);
        strcat(nc_uri->params,"]");
    }

#ifdef NC_XDEBUG
	{
        fprintf(stderr,"nc_uri:");
        fprintf(stderr," params=|%s|",FIX(nc_uri->params));
        fprintf(stderr," protocol=|%s|",FIX(nc_uri->protocol));
        fprintf(stderr," host=|%s|",FIX(nc_uri->host));
        fprintf(stderr," port=|%s|",FIX(nc_uri->port));
        fprintf(stderr," file=|%s|",FIX(nc_uri->file));
        fprintf(stderr," constraint=|%s|",FIX(nc_uri->constraint));
        fprintf(stderr,"\n");
    }
#endif
    free(uri);
    if(nc_urip != NULL) *nc_urip = nc_uri;
    return 1;

fail:
    if(nc_uri) nc_urifree(nc_uri);
    if(uri != NULL) free(uri);
    return 0;
}

void
nc_urifree(NC_URI* nc_uri)
{
    if(nc_uri == NULL) return;
    if(nc_uri->uri != NULL) {free(nc_uri->uri);}
    if(nc_uri->protocol != NULL) {free(nc_uri->protocol);}
    if(nc_uri->user != NULL) {free(nc_uri->user);}
    if(nc_uri->password != NULL) {free(nc_uri->password);}
    if(nc_uri->host != NULL) {free(nc_uri->host);}
    if(nc_uri->port != NULL) {free(nc_uri->port);}
    if(nc_uri->file != NULL) {free(nc_uri->file);}
    if(nc_uri->constraint != NULL) {free(nc_uri->constraint);}
    if(nc_uri->projection != NULL) {free(nc_uri->projection);}
    if(nc_uri->selection != NULL) {free(nc_uri->selection);}
    if(nc_uri->params != NULL) {free(nc_uri->params);}
    if(nc_uri->paramlist != NULL) nc_paramfree(nc_uri->paramlist);
    free(nc_uri);
}

/* Replace the constraints */
void
nc_urisetconstraints(NC_URI* duri,const char* constraints)
{
    char* proj = NULL;
    char* select = NULL;
    const char* p;

    if(duri->constraint == NULL) free(duri->constraint);
    if(duri->projection != NULL) free(duri->projection);
    if(duri->selection != NULL) free(duri->selection);
    duri->constraint = NULL;	
    duri->projection = NULL;	
    duri->selection = NULL;

    if(constraints == NULL || strlen(constraints)==0) return;

    duri->constraint = strdup(constraints);
    if(*duri->constraint == '?')
	strcpy(duri->constraint,duri->constraint+1);

    p = duri->constraint;
    proj = (char*) p;
    select = strchr(proj,'&');
    if(select != NULL) {
        size_t plen = (select - proj);
	if(plen == 0) {
	    proj = NULL;
	} else {
	    proj = (char*)malloc(plen+1);
	    memcpy((void*)proj,p,plen);
	    proj[plen] = '\0';
	}
	select = nulldup(select);
    } else {
	proj = nulldup(proj);
	select = NULL;
    }
    duri->projection = proj;
    duri->selection = select;
}


/* Construct a complete NC_ URI without the client params
   and optionally with the constraints;
   caller frees returned string
*/

char*
nc_uribuild(NC_URI* duri, const char* prefix, const char* suffix, int pieces)
{
    size_t len = 0;
    char* newuri;
    int withparams = ((pieces&NC_URIPARAMS)
			&& duri->params != NULL);
    int withuserpwd = ((pieces&NC_URIUSERPWD)
	               && duri->user != NULL && duri->password != NULL);
    int withconstraints = ((pieces&NC_URICONSTRAINTS)
	                   && duri->constraint != NULL);

    if(prefix != NULL) len += NILLEN(prefix);
    if(withparams) {
	len += NILLEN(duri->params);
    }
    len += (NILLEN(duri->protocol)+NILLEN("://"));
    if(withuserpwd) {
	len += (NILLEN(duri->user)+NILLEN(duri->password)+NILLEN(":@"));
    }
    len += (NILLEN(duri->host));
    if(duri->port != NULL) {
	len += (NILLEN(":")+NILLEN(duri->port));
    }
    len += (NILLEN(duri->file));
    if(suffix != NULL) len += NILLEN(suffix);
    if(withconstraints) {
	len += (NILLEN("?")+NILLEN(duri->constraint));
    }
    len += 1; /* null terminator */
    
    newuri = (char*)malloc(len);
    if(!newuri) return NULL;

    newuri[0] = '\0';
    if(prefix != NULL) strcat(newuri,prefix);
    if(withparams) {
	strcat(newuri,duri->params);
    }
    strcat(newuri,duri->protocol);
    strcat(newuri,"://");
    if(withuserpwd) {
        strcat(newuri,duri->user);
        strcat(newuri,":");
        strcat(newuri,duri->password);	
        strcat(newuri,"@");
    }
    if(duri->host != NULL) { /* may be null if using file: protocol */
        strcat(newuri,duri->host);	
    }
    if(duri->port != NULL) {
        strcat(newuri,":");
        strcat(newuri,duri->port);
    }
    strcat(newuri,duri->file);
    if(suffix != NULL) strcat(newuri,suffix);
    if(withconstraints) {
	strcat(newuri,"?");
	strcat(newuri,duri->constraint);
    }
    return newuri;
}

/**************************************************/
/* Parameter support */

/*
Client parameters are assumed to be
one or more instances of bracketed pairs:
e.g "[...][...]...".
The bracket content in turn is assumed to be a
comma separated list of <name>=<value> pairs.
e.g. x=y,z=,a=b.
If the same parameter is specifed more than once,
then the first occurrence is used; this is so that
is possible to forcibly override user specified
parameters by prefixing.
IMPORTANT: client parameter string is assumed to
have blanks compress out.
Returns 1 if parse suceeded, 0 otherwise;
*/

int
nc_uridecodeparams(NC_URI* nc_uri)
{
    char* cp;
    char* cq;
    int c;
    int i;
    int nparams;
    char* params0;
    char* params;
    char* params1;
    char** plist;

    if(nc_uri == NULL) return 0;
    if(nc_uri->params == NULL) return 1;

    params0 = nc_uri->params;

    /* Pass 1 to replace beginning '[' and ending ']' */
    if(params0[0] == '[') 
	params = strdup(params0+1);
    else
	params = strdup(params0);	

    if(params[strlen(params)-1] == ']')
	params[strlen(params)-1] = '\0';

    /* Pass 2 to replace "][" pairs with ','*/
    params1 = strdup(params);
    cp=params; cq = params1;
    while((c=*cp++)) {
	if(c == RBRACKET && *cp == LBRACKET) {cp++; c = ',';}
	*cq++ = c;
    }
    *cq = '\0';
    free(params);
    params = params1;

    /* Pass 3 to break string into pieces and count # of pairs */
    nparams=0;
    for(cp=params;(c=*cp);cp++) {
	if(c == ',') {*cp = '\0'; nparams++;}
    }
    nparams++; /* for last one */

    /* plist is an env style list */
    plist = (char**)calloc(1,sizeof(char*)*(2*nparams+1)); /* +1 for null termination */

    /* Pass 4 to break up each pass into a (name,value) pair*/
    /* and insert into the param list */
    /* parameters of the form name name= are converted to name=""*/
    cp = params;
    for(i=0;i<nparams;i++) {
	char* next = cp+strlen(cp)+1; /* save ptr to next pair*/
	char* vp;
	/*break up the ith param*/
	vp = strchr(cp,'=');
	if(vp != NULL) {*vp = '\0'; vp++;} else {vp = "";}
	plist[2*i] = strdup(cp);	
	plist[2*i+1] = strdup(vp);
	cp = next;
    }
    plist[2*nparams] = NULL;
    free(params);
    if(nc_uri->paramlist != NULL)
	nc_paramfree(nc_uri->paramlist);
    nc_uri->paramlist = plist;
    return 1;
}

int
nc_urilookup(NC_URI* uri, const char* key, const char** resultp)
{
    int i;
    char* value = NULL;
    if(uri == NULL || key == NULL || uri->params == NULL) return 0;
    if(uri->paramlist == NULL) {
	i = nc_uridecodeparams(uri);
	if(!i) return 0;
    }
    i = nc_find(uri->paramlist,key);
    if(i < 0) return 0;
    value = uri->paramlist[(2*i)+1];
    if(resultp) *resultp = value;
    return 1;
}

int
nc_urisetparams(NC_URI* uri, const char* newparams)
{
    if(uri == NULL) return 0;
    if(uri->paramlist != NULL) nc_paramfree(uri->paramlist);
    uri->paramlist = NULL;
    if(uri->params != NULL) free(uri->params);
    uri->params = nulldup(newparams);
    return 1;
}

/* Internal version of lookup; returns the paired index of the key */
static int
nc_find(char** params, const char* key)
{
    int i;
    char** p;
    for(i=0,p=params;*p;p+=2,i++) {
	if(strcmp(key,*p)==0) return i;
    }
    return -1;
}

static void
nc_paramfree(char** params)
{
    char** p;
    if(params == NULL) return;
    for(p=params;*p;p+=2) {
	free(*p);
	if(p[1] != NULL) free(p[1]);
    }
    free(params);
}