#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <ctype.h>
#include <sys/socket.h>
#include "http.h"
#include "memory.h"
#include "util.h"


static void free_list(char **list,int nitems){
	for(int i=0;i<nitems;i++){
		free(list[i]);
	}
	free(list);
}

// -2: error; -1: socket closed; >=0: length of string
static int sock_get_line(char **dst,int sock){
	int linesz=128,linelen=0;
	char *line=malloc(linesz,char);
	bool haveCR=false,alsoCR=false;
	while(true){
		char c;
		ssize_t ret=recv(sock,&c,1,0);
		if(ret<=0){
			free(line);
			*dst=NULL;
			return ret-1;
		}
		if(c=='\r'){
			haveCR=true;
			continue;
		} else if(c=='\n'){
			break;
		} else if(haveCR){
			haveCR=false;
			alsoCR=true;
		}
		if(linelen+1+alsoCR==linesz){
			linesz*=2;
			if(linesz==0){
				exit(255); // Integer overflow!
			}
			line=realloc(line,linesz,char);
		}
		if(alsoCR){
			line[linelen++]='\r';
			alsoCR=false;
		}
		line[linelen++]=c;
	}
	line[linelen]='\0';
	*dst=line;
	return linelen;
}

// Returns number of lines, or -1 if error
static int get_header_lines(char ***dst,int sock){
	int arrsz=16,arrlen=0;
	char **arr=malloc(arrsz,char*);
	while(true){
		char *line;
		int linelen=sock_get_line(&line,sock);
		if(linelen<0){
			free_list(arr,arrlen);
			*dst=NULL;
			return -1;
		}
		if(linelen==0){
			break;
		}
		if(arrlen+1==arrsz){
			arrsz*=2;
			if(arrsz==0){
				exit(255); // Integer overflow!
			}
			arr=realloc(arr,arrsz,char*);
		}
		arr[arrlen++]=line;
	}
	arr[arrlen]=NULL;
	*dst=arr;
	return arrlen;
}

static Headers* alloc_headers(void){
	Headers *headers=malloc(1,Headers);
	headers->method=NULL;
	headers->url=NULL;
	headers->version=NULL;
	headers->nheaders=0;
	headers->headers=NULL;
	return headers;
}

void free_headers(Headers *headers){
	if(headers==NULL){
		return;
	}

	if(headers->method)free(headers->method);
	if(headers->url)free(headers->url);
	if(headers->version)free(headers->version);

	if(headers->headers){
		for(int i=0;i<headers->nheaders;i++){
			free(headers->headers[i][0]);
			free(headers->headers[i][1]);
		}
		free(headers->headers);
	}

	free(headers);
}

Headers* http_get_headers(int sock){
	char **lines;
	int nlines=get_header_lines(&lines,sock);
	if(nlines<0){
		return NULL;
	}
	if(nlines==0){
		free_list(lines,nlines);
		return NULL;
	}

	char *spacep=strchr(lines[0],' ');
	char *space2p=strrchr(lines[0],' ');
	if(spacep==NULL||space2p==NULL){
		free_list(lines,nlines);
		return NULL;
	}
	char *urlstart=spacep+1;
	while(isspace(*urlstart)){
		urlstart++;
	}
	if(urlstart>space2p){ // No url?
		free_list(lines,nlines);
		return NULL;
	}

	Headers *headers=alloc_headers();

	headers->method=copy_buf(lines[0],spacep-lines[0]);
	str_toupper(headers->method);
	headers->url=copy_buf(urlstart,space2p-urlstart);
	headers->version=copy_str(space2p);
	str_toupper(headers->version);

	int hsz=16;
	headers->nheaders=0;
	headers->headers=malloc(hsz,Header);

	for(int i=1;i<nlines;i++){
		char *colonp=strchr(lines[i],':');
		if(colonp==NULL){
			free_list(lines,nlines);
			free_headers(headers);
			return NULL;
		}
		char *valuep=colonp+1;
		while(isspace(*valuep)){
			valuep++;
		}

		if(headers->nheaders+1==hsz){
			hsz*=2;
			// Don't need to check overflow, because nlines would have
			// overflowed already
			headers->headers=realloc(headers->headers,hsz,Header);
		}
		headers->headers[headers->nheaders][0]=copy_buf(lines[i],colonp-lines[i]);
		headers->headers[headers->nheaders][1]=copy_str(valuep);
		headers->nheaders++;
	}
	headers->headers[headers->nheaders][0]=NULL;
	headers->headers[headers->nheaders][1]=NULL;

	free_list(lines,nlines);
	return headers;
}