#include "httpd.h"

#include <u.h>
#include <libc.h>
#include <bio.h>
#include "httpd.h"
#include "httpsrv.h"

typedef struct Point Point;
typedef struct OkPoint OkPoint;
typedef struct Strings Strings;

struct Point
{
int x;
int y;
};

struct OkPoint
{
Point p;
int ok;
};

struct Strings
{
char *s1;
char *s2;
};

static char *me;

int polytest(int, Point, Point, Point);
Strings getfield(char*);
OkPoint pt(char*);
char* translate(HConnect*, char*, char*);
Point sub(Point, Point);
float dist(Point, Point);

void
main(int argc, char **argv)
{
HConnect *c;
Hio *hout;
char *dest;

me = "imagemap";
c = init(argc, argv);
hout = &c->hout;
if(hparseheaders(c, HSTIMEOUT) < 0)
exits("failed");
anonymous(c);

if(strcmp(c->req.meth, "GET") != 0 && strcmp(c->req.meth, "HEAD") != 0){
hunallowed(c, "GET, HEAD");
exits("unallowed");
}
if(c->head.expectother || c->head.expectcont){
hfail(c, HExpectFail, nil);
exits("failed");
}
dest = translate(c, c->req.uri, c->req.search);

if(dest == nil){
if(c->req.vermaj){
hokheaders(c);
hprint(hout, "Content-type: text/html\r\n");
hprint(hout, "\r\n");
}
hprint(hout, "<head><title>Nothing Found</title></head><body>\n");
hprint(hout, "Nothing satisfying your search request could be found.\n</body>\n");
hflush(hout);
writelog(c, "Reply: 200 imagemap %ld %ld\n", hout->seek, hout->seek);
exits(nil);
}

if(http11(c) && strcmp(c->req.meth, "POST") == 0)
hredirected(c, "303 See Other", dest);
else
hredirected(c, "302 Found", dest);
exits(nil);
}

char*
translate(HConnect *c, char *uri, char *search)
{
Biobuf *b;
Strings ss;
OkPoint okp;
Point p, cen, q, start;
float close, d;
char *line, *to, *def, *s, *dst;
int n, inside, r, ncsa;

if(search == nil){
hfail(c, HNoData, me);
exits("failed");
}
okp = pt(search);
if(!okp.ok){
hfail(c, HBadSearch, me);
exits("failed");
}
p = okp.p;

b = Bopen(uri, OREAD);
if(b == nil){
hfail(c, HNotFound, uri);
exits("failed");
}

to = nil;
def = nil;
dst = nil;
close = 0.;
ncsa = 1;
while(line = Brdline(b, '\n')){
line[Blinelen(b)-1] = 0;

ss = getfield(line);
s = ss.s1;
line = ss.s2;
if(ncsa){
ss = getfield(line);
dst = ss.s1;
line = ss.s2;
}
if(strcmp(s, "#cern") == 0){
ncsa = 0;
continue;
}
if(strcmp(s, "rect") == 0){
ss = getfield(line);
s = ss.s1;
line = ss.s2;
okp = pt(s);
q = okp.p;
if(!okp.ok || q.x > p.x || q.y > p.y)
continue;
ss = getfield(line);
s = ss.s1;
line = ss.s2;
okp = pt(s);
q = okp.p;
if(!okp.ok || q.x < p.x || q.y < p.y)
continue;
if(!ncsa){
ss = getfield(line);
dst = ss.s1;
}
return dst;
}else if(strcmp(s, "circle") == 0){
ss = getfield(line);
s = ss.s1;
line = ss.s2;
okp = pt(s);
cen = okp.p;
if(!okp.ok)
continue;
ss = getfield(line);
s = ss.s1;
line = ss.s2;
if(ncsa){
okp = pt(s);
if(!okp.ok)
continue;
if(dist(okp.p, cen) >= dist(p, cen))
return dst;
}else{
r = strtol(s, nil, 10);
ss = getfield(line);
dst = ss.s1;
d = (float)r * r;
if(d >= dist(p, cen))
return dst;
}
}else if(strcmp(s, "poly") == 0){
ss = getfield(line);
s = ss.s1;
line = ss.s2;
okp = pt(s);
start = okp.p;
if(!okp.ok)
continue;
inside = 0;
cen = start;
for(n = 1; ; n++){
ss = getfield(line);
s = ss.s1;
line = ss.s2;
okp = pt(s);
q = okp.p;
if(!okp.ok)
break;
inside = polytest(inside, p, cen, q);
cen = q;
}
inside = polytest(inside, p, cen, start);
if(!ncsa)
dst = s;
if(n >= 3 && inside)
return dst;
}else if(strcmp(s, "point") == 0){
ss = getfield(line);
s = ss.s1;
line = ss.s2;
okp = pt(s);
q = okp.p;
if(!okp.ok)
continue;
d = dist(p, q);
if(!ncsa){
ss = getfield(line);
dst = ss.s1;
}
if(d == 0.)
return dst;
if(close == 0. || d < close){
close = d;
to = dst;
}
}else if(strcmp(s, "default") == 0){
if(!ncsa){
ss = getfield(line);
dst = ss.s1;
}
def = dst;
}
}
if(to == nil)
to = def;
return to;
}

int
polytest(int inside, Point p, Point b, Point a)
{
Point pa, ba;

if(b.y>a.y){
pa=sub(p, a);
ba=sub(b, a);
}else{
pa=sub(p, b);
ba=sub(a, b);
}
if(0<=pa.y && pa.y<ba.y && pa.y*ba.x<=pa.x*ba.y)
inside = !inside;
return inside;
}

Point
sub(Point p, Point q)
{
p.x -= q.x;
p.y -= q.y;
return p;
}

float
dist(Point p, Point q)
{
p.x -= q.x;
p.y -= q.y;
return (float)p.x * p.x + (float)p.y * p.y;
}

OkPoint
pt(char *s)
{
OkPoint okp;
Point p;
char *t, *e;

if(*s == '(')
s++;
t = strchr(s, ')');
if(t != nil)
*t = 0;
p.x = 0;
p.y = 0;
t = strchr(s, ',');
if(t == nil){
okp.p = p;
okp.ok = 0;
return okp;
}
e = nil;
p.x = strtol(s, &e, 10);
if(e != t){
okp.p = p;
okp.ok = 0;
return okp;
}
p.y = strtol(t+1, &e, 10);
if(e == nil || *e != 0){
okp.p = p;
okp.ok = 0;
return okp;
}
okp.p = p;
okp.ok = 1;
return okp;
}

Strings
getfield(char *s)
{
Strings ss;
char *f;

while(*s == '\t' || *s == ' ')
s++;
f = s;
while(*s && *s != '\t' && *s != ' ')
s++;
if(*s)
*s++ = 0;
ss.s1 = f;
ss.s2 = s;
return ss;
}