/*
 *  server.c
 * 
 *  Copyright (c) 2006 by Miklos Vajna <vmiklos@frugalware.org>
 * 
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 
 *  USA.
 */

#include "config.h"

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
#include <errno.h>
#include <download.h>

/* libalpm */
#include "server.h"
#include "alpm_list.h"
#include "error.h"
#include "log.h"
#include "alpm.h"
#include "util.h"
#include "handle.h"
#include "package.h"

/** Fetch a remote pkg.
 * @param url
 * @return the downloaded filename on success, NULL on error
 * @addtogroup alpm_misc
 */
char SYMEXPORT *alpm_fetch_pkgurl(const char *url)
{
	ALPM_LOG_FUNC;

	ASSERT(strstr(url, "://"), return(NULL));

	return(_alpm_fetch_pkgurl(url));
}

pmserver_t *_alpm_server_new(const char *url)
{
	struct url *u;
	pmserver_t *server;

	ALPM_LOG_FUNC;

	server = malloc(sizeof(pmserver_t));
	if(server == NULL) {
		_alpm_log(PM_LOG_ERROR, _("malloc failure: could not allocate %d bytes"), sizeof(pmserver_t));
		RET_ERR(PM_ERR_MEMORY, NULL);
	}

	memset(server, 0, sizeof(pmserver_t));
	u = downloadParseURL(url);
	if(!u) {
		_alpm_log(PM_LOG_ERROR, _("url '%s' is invalid, ignoring"), url);
		RET_ERR(PM_ERR_SERVER_BAD_URL, NULL);
	}
	if(strlen(u->scheme) == 0) {
		_alpm_log(PM_LOG_WARNING, _("url scheme not specified, assuming http"));
		strcpy(u->scheme, "http");
	}

	if(strcmp(u->scheme,"ftp") == 0 && strlen(u->user) == 0) {
		strcpy(u->user, "anonymous");
		strcpy(u->pwd, "libalpm@guest");
	}

	/* remove trailing slashes, just to clean up the rest of the code */
	for(int i = strlen(u->doc) - 1; u->doc[i] == '/'; --i)
		u->doc[i] = '\0';

  server->s_url = u;

	return server;
}

void _alpm_server_free(pmserver_t *server)
{
	ALPM_LOG_FUNC;

	if(server == NULL) {
		return;
	}

	/* free memory */
	downloadFreeURL(server->s_url);
	FREE(server);
}

/* remove filename info from "s_url->doc" and return it */
static char *strip_filename(pmserver_t *server)
{
	char *p = NULL, *fname = NULL;
	if(!server) {
		return(NULL);
	}

	p = strrchr(server->s_url->doc, '/');
	if(p && *(++p)) {
		fname = strdup(p);
		_alpm_log(PM_LOG_DEBUG, "stripping '%s' from '%s'",
				fname, server->s_url->doc);
		*p = 0;
	}

	/* s_url->doc now contains ONLY path information.  return value
	 * if the file information from the original URL */
	return(fname);
}

/* Return a 'struct url' for this server, for downloading 'filename'. */
static struct url *url_for_file(pmserver_t *server, const char *filename)
{
	struct url *ret = NULL;
	char *doc = NULL;
	int doclen = 0;

	doclen = strlen(server->s_url->doc) + strlen(filename) + 2;
	doc = calloc(doclen, sizeof(char));
	if(!doc) {
		RET_ERR(PM_ERR_MEMORY, NULL);
	}

	snprintf(doc, doclen, "%s/%s", server->s_url->doc, filename);
	ret = downloadMakeURL(server->s_url->scheme,
												server->s_url->host,
												server->s_url->port,
												doc,
												server->s_url->user,
												server->s_url->pwd);
	free(doc);
	return(ret);
}

/*
 * Download a list of files from a list of servers
 *   - if one server fails, we try the next one in the list
 *
 * RETURN:  0 for successful download, 1 on error
 */
int _alpm_downloadfiles(alpm_list_t *servers, const char *localpath, alpm_list_t *files)
{
	ALPM_LOG_FUNC;
	return(_alpm_downloadfiles_forreal(servers, localpath, files, NULL, NULL));
}

/*
 * This is the real downloadfiles, used directly by sync_synctree() to check
 * modtimes on remote files.
 *   - if *mtime1 is non-NULL, then only download files
 *     if they are different than *mtime1.  String should be in the form
 *     "YYYYMMDDHHMMSS" to match the form of ftplib's FtpModDate() function.
 *   - if *mtime2 is non-NULL, then it will be filled with the mtime
 *     of the remote file (from MDTM FTP cmd or Last-Modified HTTP header).
 * 
 * RETURN:  0 for successful download
 *          1 if the mtimes are identical
 *         -1 on error
 */
int _alpm_downloadfiles_forreal(alpm_list_t *servers, const char *localpath,
	alpm_list_t *files, const char *mtime1, char *mtime2)
{
	int dltotal_bytes = 0;
	alpm_list_t *lp;
	int done = 0;
	alpm_list_t *complete = NULL;
	alpm_list_t *i;

	ALPM_LOG_FUNC;

	if(files == NULL) {
		return(0);
	}

	for(i = servers; i && !done; i = i->next) {
		pmserver_t *server = i->data;

		/* get each file in the list */
		for(lp = files; lp; lp = lp->next) {
			struct url *fileurl = NULL;
			char realfile[PATH_MAX];
			char output[PATH_MAX];
			char *fn = (char *)lp->data;
			char pkgname[PKG_NAME_LEN];
			char *p;

			fileurl = url_for_file(server, fn);
			if(!fileurl) {
				return(-1);
			}

			/* Try to get JUST the name of the package from the filename */
			memset(pkgname, 0, PKG_NAME_LEN);
			if((p = strstr(fn, PKGEXT))) {
				_alpm_pkg_splitname(fn, pkgname, NULL, 1);
			}
			if(!strlen(pkgname)) {
				/* just use the raw filename if we can't find crap */
				strncpy(pkgname, fn, PKG_NAME_LEN);
			}
			_alpm_log(PM_LOG_DEBUG, "using '%s' for download progress", pkgname);

			snprintf(realfile, PATH_MAX, "%s%s", localpath, fn);
			snprintf(output, PATH_MAX, "%s%s.part", localpath, fn);

			if(alpm_list_find_str(complete, fn)) {
				continue;
			}

			if(!handle->xfercommand || !strcmp(fileurl->scheme, "file")) {
				FILE *dlf, *localf = NULL;
				struct url_stat ust;
				struct stat st;
				int chk_resume = 0;

				if(stat(output, &st) == 0 && st.st_size > 0) {
					_alpm_log(PM_LOG_DEBUG, "existing file found, using it");
					fileurl->offset = (off_t)st.st_size;
					dltotal_bytes = st.st_size;
					localf = fopen(output, "a");
					chk_resume = 1;
				} else {
					fileurl->offset = (off_t)0;
					dltotal_bytes = 0;
				}
				
				/* libdownload does not reset the error code, reset it in the case of previous errors */
				downloadLastErrCode = 0;

				/* 10s timeout - TODO make a config option */
				downloadTimeout = 10000;

				dlf = downloadXGet(fileurl, &ust, (handle->nopassiveftp ? "" : "p"));

				if(downloadLastErrCode != 0 || dlf == NULL) {
					_alpm_log(PM_LOG_ERROR, _("failed retrieving file '%s' from %s : %s"),
										fn, fileurl->host, downloadLastErrString);
					if(localf != NULL) {
						fclose(localf);
					}
					/* try the next server */
					continue;
				} else {
						_alpm_log(PM_LOG_DEBUG, "connected to %s successfully", fileurl->host);
				}
				
				if(ust.mtime && mtime1) {
					char strtime[15];
					_alpm_time2string(ust.mtime, strtime);
					if(strcmp(mtime1, strtime) == 0) {
						_alpm_log(PM_LOG_DEBUG, "mtimes are identical, skipping %s", fn);
						complete = alpm_list_add(complete, fn);
						if(localf != NULL) {
							fclose(localf);
						}
						if(dlf != NULL) {
							fclose(dlf);
						}
						return(1);
					}
				}
				
				if(ust.mtime && mtime2) {
					_alpm_time2string(ust.mtime, mtime2);
				}

				if(chk_resume && fileurl->offset == 0) {
					_alpm_log(PM_LOG_WARNING, _("cannot resume download, starting over"));
					if(localf != NULL) {
						fclose(localf);
						localf = NULL;
					}
				}

				if(localf == NULL) {
					_alpm_rmrf(output);
					fileurl->offset = (off_t)0;
					dltotal_bytes = 0;
					localf = fopen(output, "w");
					if(localf == NULL) { /* still null? */
						_alpm_log(PM_LOG_ERROR, _("cannot write to file '%s'"), output);
						if(dlf != NULL) {
							fclose(dlf);
						}
						return -1;
					}
				}

				/* Progress 0 - initialize */
				if(handle->dlcb) handle->dlcb(pkgname, 0, ust.size);

				int nread = 0;
				char buffer[PM_DLBUF_LEN];
				while((nread = fread(buffer, 1, PM_DLBUF_LEN, dlf)) > 0) {
					if(ferror(dlf)) {
						_alpm_log(PM_LOG_ERROR, _("error downloading '%s': %s"),
											fn, downloadLastErrString);
						fclose(localf);
						fclose(dlf);
						return(-1);
					}
					
					int nwritten = 0;
					while(nwritten < nread) {
						nwritten += fwrite(buffer, 1, (nread - nwritten), localf);
						if(ferror(localf)) {
							_alpm_log(PM_LOG_ERROR, _("error writing to file '%s': %s"),
												realfile, strerror(errno));
							fclose(localf);
							fclose(dlf);
							return(-1);
						}
					}

					if(nwritten != nread) {
						
					}
					dltotal_bytes += nread;

					if(handle->dlcb) handle->dlcb(pkgname, dltotal_bytes, ust.size);
				}

				fclose(localf);
				fclose(dlf);
				rename(output, realfile);
				complete = alpm_list_add(complete, fn);
			} else {
				int ret;
				int usepart = 0;
				char *ptr1, *ptr2;
				char origCmd[PATH_MAX];
				char parsedCmd[PATH_MAX] = "";
				char url[PATH_MAX];
				char cwd[PATH_MAX];

				/* build the full download url */
				snprintf(url, PATH_MAX, "%s://%s%s", fileurl->scheme, fileurl->host, fileurl->doc);

				/* replace all occurrences of %o with fn.part */
				strncpy(origCmd, handle->xfercommand, sizeof(origCmd));
				ptr1 = origCmd;
				while((ptr2 = strstr(ptr1, "%o"))) {
					usepart = 1;
					ptr2[0] = '\0';
					strcat(parsedCmd, ptr1);
					strcat(parsedCmd, output);
					ptr1 = ptr2 + 2;
				}
				strcat(parsedCmd, ptr1);
				/* replace all occurrences of %u with the download URL */
				strncpy(origCmd, parsedCmd, sizeof(origCmd));
				parsedCmd[0] = '\0';
				ptr1 = origCmd;
				while((ptr2 = strstr(ptr1, "%u"))) {
					ptr2[0] = '\0';
					strcat(parsedCmd, ptr1);
					strcat(parsedCmd, url);
					ptr1 = ptr2 + 2;
				}
				strcat(parsedCmd, ptr1);
				/* cwd to the download directory */
				getcwd(cwd, PATH_MAX);
				if(chdir(localpath)) {
					_alpm_log(PM_LOG_WARNING, _("could not chdir to %s"), localpath);
					return(PM_ERR_CONNECT_FAILED);
				}
				/* execute the parsed command via /bin/sh -c */
				_alpm_log(PM_LOG_DEBUG, "running command: %s", parsedCmd);
				ret = system(parsedCmd);
				if(ret == -1) {
					_alpm_log(PM_LOG_WARNING, _("running XferCommand: fork failed!"));
					return(PM_ERR_FORK_FAILED);
				} else if(ret != 0) {
					/* download failed */
					_alpm_log(PM_LOG_DEBUG, "XferCommand command returned non-zero status code (%d)", ret);
				} else {
					/* download was successful */
					complete = alpm_list_add(complete, fn);
					if(usepart) {
						rename(output, realfile);
					}
				}
				chdir(cwd);
			}
			downloadFreeURL(fileurl);
		}

		if(alpm_list_count(complete) == alpm_list_count(files)) {
			done = 1;
		}
	}

	return(done ? 0 : -1);
}

char *_alpm_fetch_pkgurl(const char *target)
{
	pmserver_t *server;
	char *filename;
	struct stat st;

	ALPM_LOG_FUNC;

	server = _alpm_server_new(target);
	if(!server) {
		return(NULL);
	}

	/* strip path information from the filename */
	filename = strip_filename(server);
	if(!filename) {
		_alpm_log(PM_LOG_ERROR, _("URL does not contain a file for download"));
		return(NULL);
	}

	/* do not download the file if it exists in the current dir */
	if(stat(filename, &st) == 0) {
		_alpm_log(PM_LOG_DEBUG, "%s has already been downloaded", filename);
	} else {
		alpm_list_t *servers = alpm_list_add(NULL, server);
		alpm_list_t *files = alpm_list_add(NULL, filename);

		if(_alpm_downloadfiles(servers, "./", files)) {
			_alpm_log(PM_LOG_WARNING, _("failed to download %s"), target);
			return(NULL);
		}
		_alpm_log(PM_LOG_DEBUG, "successfully downloaded %s", filename);
		alpm_list_free(files);
		alpm_list_free(servers);
	}

	_alpm_server_free(server);

	/* return the target with the raw filename, no URL */
	return(filename);
}

/* vim: set ts=2 sw=2 noet: */