// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2012 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC.  If not, see <http://www.gnu.org/licenses/>.

// scheduler component for data archival.
// Called on each scheduler request.

#ifdef _USING_FCGI_
#include "boinc_fcgi.h"
#else
#include <cstdio>
#endif

#include <map>
#include <string>

#include "filesys.h"

#include "backend_lib.h"

#include "sched_config.h"
#include "sched_msgs.h"
#include "sched_types.h"
#include "sched_util.h"

#include "vda_lib.h"

#include "sched_vda.h"

using std::map;
using std::string;
using std::pair;

// mark a vda_file for update by vdad
//
static int mark_for_update(int vda_file_id) {
    DB_VDA_FILE f;
    f.id = vda_file_id;
    return f.update_field("need_update=1");
}

typedef map<string, DB_VDA_CHUNK_HOST> CHUNK_LIST;

// get the path to the chunk's directory
//
static void get_chunk_dir(DB_VDA_FILE& vf, const char* chunk_name, char* dir) {
    char chunk_dirs[256];
    strcpy(chunk_dirs, chunk_name);
    while (1) {
        char* p = strchr(chunk_dirs, '.');
        if (!p) break;
        *p = '/';
    }
    sprintf(dir, "%s/%s", vf.dir, chunk_dirs);
}

static void get_chunk_url(DB_VDA_FILE& vf, const char* chunk_name, char* url) {
    char chunk_dirs[256], buf[1024];
    strcpy(chunk_dirs, chunk_name);
    while (1) {
        char* p = strchr(chunk_dirs, '.');
        if (!p) break;
        *p = '/';
    }
    dir_hier_url(vf.name, config.download_url, config.uldl_dir_fanout, buf);
    sprintf(url, "%s/%s/data.vda", buf, chunk_dirs);
}

// read the chunk's MD5 file into a buffer
//
static int get_chunk_md5(char* chunk_dir, char* md5_buf) {
    char md5_path[1024];
    sprintf(md5_path, "%s/md5.txt", chunk_dir);
#ifndef _USING_FCGI_
    FILE* f = fopen(md5_path, "r");
#else
    FCGI_FILE* f = FCGI::fopen(md5_path, "r");
#endif
    if (!f) return ERR_FOPEN;
    char* p = fgets(md5_buf, 64, f);
    fclose(f);
    if (p == NULL) return ERR_GETS;
    strip_whitespace(md5_buf);
    return 0;
}

// process a completed upload:
// if vda_chunk_host found
//      verify md5 of upload
//      move it from upload dir to vda_file dir
//      mark vda_file for update
//      clear transfer_in_progress flag in vda_chunk_host
// else
//      delete from upload dir
//
static int process_completed_upload(char* chunk_name, CHUNK_LIST& chunks) {
    char path[1024], client_filename[1024], dir[1024];
    int retval;

    sprintf(client_filename, "%d_%s", g_reply->host.id, chunk_name);
    dir_hier_path(
        client_filename, config.upload_dir, config.uldl_dir_fanout, dir, false
    );
    sprintf(path, "%s/%s", dir, client_filename);
    CHUNK_LIST::iterator i2 = chunks.find(string(chunk_name));
    if (i2 == chunks.end()) {
        if (config.debug_vda) {
            log_messages.printf(MSG_NORMAL,
                "[vda] chunk_host not found for %s\n", chunk_name
            );
        }
        boinc_delete_file(path);
    } else {
        char client_md5[64], server_md5[64];
        char chunk_dir[1024];
        DB_VDA_CHUNK_HOST& ch = i2->second;
        DB_VDA_FILE vf;
        double size;

        retval = vf.lookup_id(ch.vda_file_id);
        get_chunk_dir(vf, chunk_name, chunk_dir);
        retval = get_chunk_md5(chunk_dir, server_md5);
        if (retval) return retval;
        retval = md5_file(path, client_md5, size);
        if (retval) return retval;
        if (strcmp(client_md5, server_md5)) {
            if (config.debug_vda) {
                log_messages.printf(MSG_NORMAL,
                    "[vda] MD5 mismatch %s %s\n", client_md5, server_md5
                );
            }
            boinc_delete_file(path);
        } else {
            retval = vf.update_field("need_update=1");
            if (retval) return retval;
            retval = ch.update_field("transfer_in_progress=0");
            if (retval) return retval;
        }
    }
    return 0;
}

// process a present file
// - create a vda_chunk_host record if needed
// - set present_on_host flag in vda_chunk_host
// - mark our in-memory vda_chunk_host record as "found"
// - mark vda_file for update
//
static int process_present_file(FILE_INFO& fi, CHUNK_LIST& chunks) {
    return 0;
}

// for each vda_chunk_host not in file list:
// - delete from DB
// - mark vda_file for update
//
static int process_missing_chunks(CHUNK_LIST& chunks) {
    CHUNK_LIST::iterator it;
    for (it = chunks.begin(); it != chunks.end(); it++) {
        DB_VDA_CHUNK_HOST& ch = it->second;
        if (!ch.present_on_host && ch.transfer_in_progress) continue;
        if (!ch.found) {
            if (config.debug_vda) {
                log_messages.printf(MSG_NORMAL,
                    "[vda] in DB but not on client: %s\n", ch.name
                );
            }
            ch.delete_from_db();
            ch.transfer_in_progress = false;
            mark_for_update(ch.vda_file_id);
        }
    }
    return 0;
}

// if process is using more than its share of disk space,
// remove some chunks and mark vda_files for update
//
static int enforce_quota(CHUNK_LIST& chunks) {
    if (!g_request->host.d_project_share) return 0;

    double x = g_request->host.d_boinc_used_project;
    if (config.debug_vda) {
        log_messages.printf(MSG_NORMAL,
            "[vda] share: %f used: %f\n",
            g_request->host.d_project_share, x
        );
    }
    CHUNK_LIST::iterator it = chunks.begin();
    while (x > g_request->host.d_project_share && it != chunks.end()) {
        DB_VDA_CHUNK_HOST& ch = it->second;
        if (!ch.found) continue;
        FILE_INFO fi;
        strcpy(fi.name, ch.name);
        if (config.debug_vda) {
            log_messages.printf(MSG_NORMAL,
                "[vda] deleting: %s\n", ch.name
            );
        }
        x -= ch.size;
        g_reply->file_deletes.push_back(fi);
        it++;
    }
    return 0;
}

// issue upload and download commands
//
static int issue_transfer_commands(CHUNK_LIST& chunks) {
    char xml_buf[8192], file_name[1024];
    int retval;
    char url[1024];

    CHUNK_LIST::iterator it;
    for (it = chunks.begin(); it != chunks.end(); it++) {
        vector<const char*> urls;
        DB_VDA_CHUNK_HOST& ch = it->second;
        if (!ch.transfer_in_progress) continue;
        if (!ch.transfer_wait) continue;
        DB_VDA_FILE vf;
        retval = vf.lookup_id(ch.vda_file_id);
        if (retval) return retval;
        if (ch.present_on_host) {
            if (config.debug_vda) {
                log_messages.printf(MSG_NORMAL,
                    "[vda] sending upload command: %s\n", ch.name
                );
            }
            // upload
            //
            sprintf(file_name, "%d_%s__%s", g_reply->host.id, ch.name, vf.name);
            urls.push_back(config.upload_url);
            R_RSA_PRIVATE_KEY key;
            retval = get_file_xml(
                file_name,
                urls,
                ch.size,
                dtime() + VDA_HOST_TIMEOUT,
                false,
                key,
                xml_buf
            );
        } else {
            if (config.debug_vda) {
                log_messages.printf(MSG_NORMAL,
                    "[vda] sending download command: %s\n", ch.name
                );
            }
            // download
            //
            char md5[64], chunk_dir[1024];
            sprintf(file_name, "%s__%s", ch.name, vf.name);
            get_chunk_url(vf, ch.name, url);
            urls.push_back(url);
            get_chunk_dir(vf, ch.name, chunk_dir);
            retval = get_chunk_md5(chunk_dir, md5);
            if (retval) return retval;
            retval = put_file_xml(
                file_name,
                urls,
                md5,
                ch.size,
                dtime() + VDA_HOST_TIMEOUT,
                xml_buf
            );
        }
        g_reply->file_transfer_requests.push_back(string(xml_buf));
    }
    return 0;
}

// handle a scheduler request:
//
// - handle completed uploads
// - handle set of files present on client
//   (update or create VDA_CHUNK_HOST record)
// - handle files expected but not present
// - issue delete commands if needed to enforce share
// - issue upload or download commands to client
//
// relevant fields of SCHEDULER_REQUEST
// file_infos: list of sticky files
// file_xfer_results: list of completed file xfers
//
void handle_vda() {
    int retval;
    unsigned int i;
    CHUNK_LIST chunks;
        // chunks that are supposed to be on this host

    // enumerate the vda_chunk_host records for this host from DB
    //
    DB_VDA_CHUNK_HOST ch;
    char buf[256];
    sprintf(buf, "where host_id=%d", g_reply->host.id);
    while (1) {
        retval = ch.enumerate(buf);
        if (retval == ERR_DB_NOT_FOUND) break;
        if (retval) {
            // if we didn't get a complete enumeration,
            // give up rather than continuing with partial info
            //
            log_messages.printf(MSG_NORMAL,
                "[vda]: ch.enumerate() failed %d\n", retval
            );
            return;
        }
        if (config.debug_vda) {
            log_messages.printf(MSG_NORMAL,
                "[vda] DB: has chunk %s\n", ch.name
            );
        }
        chunks.insert(pair<string, DB_VDA_CHUNK_HOST>(string(ch.name), ch));
    }

    // process completed uploads
    //
    for (i=0; i<g_request->file_xfer_results.size(); i++) {
        RESULT& r = g_request->file_xfer_results[i];
        if (!starts_with(r.name, "vda_upload_")) continue;
        char* chunk_name = r.name + strlen("vda_upload_");
        if (config.debug_vda) {
            log_messages.printf(MSG_NORMAL,
                "[vda] DB: completed upload %s\n", chunk_name
            );
        }
        retval = process_completed_upload(chunk_name, chunks);
        if (retval) {
            log_messages.printf(MSG_CRITICAL,
                "[vda] process_completed_upload(): %d\n", retval
            );
            return;
        }
    }

    // process files present on host
    //
    for (i=0; i<g_request->file_infos.size(); i++) {
        FILE_INFO& fi = g_request->file_infos[i];
        if (!starts_with(fi.name, "vda_")) {
            continue;
        }
        if (config.debug_vda) {
            log_messages.printf(MSG_NORMAL,
                "[vda] request: client has file %s\n", fi.name
            );
        }
        process_present_file(fi, chunks);
    }

    process_missing_chunks(chunks);

    enforce_quota(chunks);

    issue_transfer_commands(chunks);
}