/* This file is part of the YAZ toolkit.
 * Copyright (C) Index Data
 * See the file LICENSE for details.
 */
/**
 * \file url.c
 * \brief URL fetch utility
 */
#if HAVE_CONFIG_H
#include <config.h>
#endif

#include <yaz/url.h>
#include <yaz/comstack.h>
#include <yaz/log.h>
#include <yaz/wrbuf.h>
#include <yaz/cookie.h>

struct yaz_url {
    ODR odr_in;
    ODR odr_out;
    char *proxy;
    int max_redirects;
    WRBUF w_error;
    int verbose;
    yaz_cookies_t cookies;
};

yaz_url_t yaz_url_create(void)
{
    yaz_url_t p = xmalloc(sizeof(*p));
    p->odr_in = odr_createmem(ODR_DECODE);
    p->odr_out = odr_createmem(ODR_ENCODE);
    p->proxy = 0;
    p->max_redirects = 10;
    p->w_error = wrbuf_alloc();
    p->verbose = 0;
    p->cookies = yaz_cookies_create();
    return p;
}

void yaz_url_destroy(yaz_url_t p)
{
    if (p)
    {
        odr_destroy(p->odr_in);
        odr_destroy(p->odr_out);
        xfree(p->proxy);
        wrbuf_destroy(p->w_error);
        yaz_cookies_destroy(p->cookies);
        xfree(p);
    }
}

void yaz_url_set_proxy(yaz_url_t p, const char *proxy)
{
    xfree(p->proxy);
    p->proxy = 0;
    if (proxy && *proxy)
        p->proxy = xstrdup(proxy);
}

void yaz_url_set_max_redirects(yaz_url_t p, int num)
{
    p->max_redirects = num;
}

void yaz_url_set_verbose(yaz_url_t p, int num)
{
    p->verbose = num;
}

static void extract_user_pass(NMEM nmem,
                              const char *uri,
                              char **uri_lean, char **http_user,
                              char **http_pass)
{
    const char *cp1 = strchr(uri, '/');
    *uri_lean = 0;
    *http_user = 0;
    *http_pass = 0;
    if (cp1 && cp1 > uri)
    {
        cp1--;

        if (!strncmp(cp1, "://", 3))
        {
            const char *cp3 = 0;
            const char *cp2 = cp1 + 3;
            while (*cp2 && *cp2 != '/' && *cp2 != '@')
            {
                if (*cp2 == ':')
                    cp3 = cp2;
                cp2++;
            }
            if (*cp2 == '@' && cp3)
            {
                *uri_lean = nmem_malloc(nmem, strlen(uri) + 1);
                memcpy(*uri_lean, uri, cp1 + 3 - uri);
                strcpy(*uri_lean + (cp1 + 3 - uri), cp2 + 1);

                *http_user = nmem_strdupn(nmem, cp1 + 3, cp3 - (cp1 + 3));
                *http_pass = nmem_strdupn(nmem, cp3 + 1, cp2 - (cp3 + 1));
            }
        }
    }
    if (*uri_lean == 0)
        *uri_lean = nmem_strdup(nmem, uri);
}

const char *yaz_url_get_error(yaz_url_t p)
{
    return wrbuf_cstr(p->w_error);
}

static void log_warn(yaz_url_t p)
{
    yaz_log(YLOG_WARN, "yaz_url: %s", wrbuf_cstr(p->w_error));
}

Z_HTTP_Response *yaz_url_exec(yaz_url_t p, const char *uri,
                              const char *method,
                              Z_HTTP_Header *user_headers,
                              const char *buf, size_t len)
{
    Z_HTTP_Response *res = 0;
    int number_of_redirects = 0;

    yaz_cookies_reset(p->cookies);
    wrbuf_rewind(p->w_error);
    while (1)
    {
        void *add;
        COMSTACK conn = 0;
        int code;
        const char *location = 0;
        char *http_user = 0;
        char *http_pass = 0;
        char *uri_lean = 0;
        Z_GDU *gdu;

        extract_user_pass(p->odr_out->mem, uri, &uri_lean,
                          &http_user, &http_pass);

        gdu = z_get_HTTP_Request_uri(p->odr_out, uri_lean, 0, p->proxy ? 1 : 0);
        gdu->u.HTTP_Request->method = odr_strdup(p->odr_out, method);

        yaz_cookies_request(p->cookies, p->odr_out, gdu->u.HTTP_Request);
        for ( ; user_headers; user_headers = user_headers->next)
        {
            /* prefer new Host over user-supplied Host */
            if (!strcmp(user_headers->name, "Host"))
                ;
            /* prefer user-supplied User-Agent over YAZ' own */
            else if (!strcmp(user_headers->name, "User-Agent"))
                z_HTTP_header_set(p->odr_out, &gdu->u.HTTP_Request->headers,
                                  user_headers->name, user_headers->value);
            else
                z_HTTP_header_add(p->odr_out, &gdu->u.HTTP_Request->headers,
                                  user_headers->name, user_headers->value);
        }
        if (http_user && http_pass)
            z_HTTP_header_add_basic_auth(p->odr_out,
                                         &gdu->u.HTTP_Request->headers,
                                         http_user, http_pass);

        res = 0;
        if (buf && len)
        {
            gdu->u.HTTP_Request->content_buf = (char *) buf;
            gdu->u.HTTP_Request->content_len = len;
        }
        if (!z_GDU(p->odr_out, &gdu, 0, 0))
        {
            wrbuf_printf(p->w_error, "Can not encode HTTP request for URL %s",
                         uri);
            log_warn(p);
            return 0;
        }
        conn = cs_create_host_proxy(uri_lean, 1, &add, p->proxy);
        if (!conn)
        {
            wrbuf_printf(p->w_error, "Can not resolve URL %s", uri);
            log_warn(p);
        }
        else if (cs_connect(conn, add) < 0)
        {
            wrbuf_printf(p->w_error, "Can not connect to URL %s", uri);
            log_warn(p);
        }
        else
        {
            int len;
            char *buf = odr_getbuf(p->odr_out, &len, 0);

            if (p->verbose)
                fwrite(buf, 1, len, stdout);

            if (cs_put(conn, buf, len) < 0)
            {
                wrbuf_printf(p->w_error, "cs_put fail for URL %s", uri);
                log_warn(p);
            }
            else
            {
                char *netbuffer = 0;
                int netlen = 0;
                int cs_res = cs_get(conn, &netbuffer, &netlen);
                if (cs_res <= 0)
                {
                    wrbuf_printf(p->w_error, "cs_get failed for URL %s", uri);
                    log_warn(p);
                }
                else
                {
                    Z_GDU *gdu;
                    if (p->verbose)
                        fwrite(netbuffer, 1, cs_res, stdout);
                    odr_setbuf(p->odr_in, netbuffer, cs_res, 0);
                    if (!z_GDU(p->odr_in, &gdu, 0, 0)
                        || gdu->which != Z_GDU_HTTP_Response)
                    {
                        wrbuf_printf(p->w_error, "HTTP decoding fail for "
                                     "URL %s", uri);
                        log_warn(p);
                    }
                    else
                    {
                        res = gdu->u.HTTP_Response;
                    }
                }
                xfree(netbuffer);
            }
        }
        if (conn)
            cs_close(conn);
        if (!res)
            break;
        code = res->code;
        location = z_HTTP_header_lookup(res->headers, "Location");
        if (++number_of_redirects <= p->max_redirects &&
            location && (code == 301 || code == 302 || code == 307))
        {
            int host_change = 0;
            const char *nlocation = yaz_check_location(p->odr_in, uri,
                                                       location, &host_change);

            odr_reset(p->odr_out);
            uri = odr_strdup(p->odr_out, nlocation);
        }
        else
            break;
        yaz_cookies_response(p->cookies, res);
        odr_reset(p->odr_in);
    }
    return res;
}

/*
 * Local variables:
 * c-basic-offset: 4
 * c-file-style: "Stroustrup"
 * indent-tabs-mode: nil
 * End:
 * vim: shiftwidth=4 tabstop=8 expandtab
 */