/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#define LOG_TAG "incidentd"

#include "Reporter.h"
#include "protobuf.h"

#include "report_directory.h"
#include "section_list.h"

#include <private/android_filesystem_config.h>
#include <android/os/DropBoxManager.h>
#include <utils/SystemClock.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <errno.h>

/**
 * The directory where the incident reports are stored.
 */
static const String8 INCIDENT_DIRECTORY("/data/incidents");

static status_t
write_all(int fd, uint8_t const* buf, size_t size)
{
    while (size > 0) {
        ssize_t amt = ::write(fd, buf, size);
        if (amt < 0) {
            return -errno;
        }
        size -= amt;
        buf += amt;
    }
    return NO_ERROR;
}

// ================================================================================
ReportRequest::ReportRequest(const IncidentReportArgs& a,
            const sp<IIncidentReportStatusListener> &l, int f)
    :args(a),
     listener(l),
     fd(f),
     err(NO_ERROR)
{
}

ReportRequest::~ReportRequest()
{
}

// ================================================================================
ReportRequestSet::ReportRequestSet()
    :mRequests(),
     mWritableCount(0),
     mMainFd(-1)
{
}

ReportRequestSet::~ReportRequestSet()
{
}

void
ReportRequestSet::add(const sp<ReportRequest>& request)
{
    mRequests.push_back(request);
    mWritableCount++;
}

void
ReportRequestSet::setMainFd(int fd)
{
    mMainFd = fd;
    mWritableCount++;
}

status_t
ReportRequestSet::write(uint8_t const* buf, size_t size)
{
    status_t err = EBADF;

    // The streaming ones
    int const N = mRequests.size();
    for (int i=N-1; i>=0; i--) {
        sp<ReportRequest> request = mRequests[i];
        if (request->fd >= 0 && request->err == NO_ERROR) {
            err = write_all(request->fd, buf, size);
            if (err != NO_ERROR) {
                request->err = err;
                mWritableCount--;
            }
        }
    }

    // The dropbox file
    if (mMainFd >= 0) {
        err = write_all(mMainFd, buf, size);
        if (err != NO_ERROR) {
            mMainFd = -1;
            mWritableCount--;
        }
    }

    // Return an error only when there are no FDs to write.
    return mWritableCount > 0 ? NO_ERROR : err;
}


// ================================================================================
Reporter::Reporter()
    :args(),
     batch()
{
    char buf[100];

    // TODO: Make the max size smaller for user builds.
    mMaxSize = 100 * 1024 * 1024;
    mMaxCount = 100;

    // There can't be two at the same time because it's on one thread.
    mStartTime = time(NULL);
    strftime(buf, sizeof(buf), "/incident-%Y%m%d-%H%M%S", localtime(&mStartTime));
    mFilename = INCIDENT_DIRECTORY + buf;
}

Reporter::~Reporter()
{
}

Reporter::run_report_status_t
Reporter::runReport()
{

    status_t err = NO_ERROR;
    bool needMainFd = false;
    int mainFd = -1;

    // See if we need the main file
    for (ReportRequestSet::iterator it=batch.begin(); it!=batch.end(); it++) {
        if ((*it)->fd < 0 && mainFd < 0) {
            needMainFd = true;
            break;
        }
    }
    if (needMainFd) {
        // Create the directory
        err = create_directory(INCIDENT_DIRECTORY);
        if (err != NO_ERROR) {
            goto done;
        }

        // If there are too many files in the directory (for whatever reason),
        // delete the oldest ones until it's under the limit. Doing this first
        // does mean that we can go over, so the max size is not a hard limit.
        clean_directory(INCIDENT_DIRECTORY, mMaxSize, mMaxCount);

        // Open the file.
        err = create_file(&mainFd);
        if (err != NO_ERROR) {
            goto done;
        }

        // Add to the set
        batch.setMainFd(mainFd);
    }

    // Tell everyone that we're starting.
    for (ReportRequestSet::iterator it=batch.begin(); it!=batch.end(); it++) {
        if ((*it)->listener != NULL) {
            (*it)->listener->onReportStarted();
        }
    }

    // Write the incident headers
    for (ReportRequestSet::iterator it=batch.begin(); it!=batch.end(); it++) {
        const sp<ReportRequest> request = (*it);
        const vector<vector<int8_t>>& headers = request->args.headers();

        for (vector<vector<int8_t>>::const_iterator buf=headers.begin(); buf!=headers.end();
                buf++) {
            int fd = request->fd >= 0 ? request->fd : mainFd;

            uint8_t buffer[20];
            uint8_t* p = write_length_delimited_tag_header(buffer, FIELD_ID_INCIDENT_HEADER,
                    buf->size());
            write_all(fd, buffer, p-buffer);

            write_all(fd, (uint8_t const*)buf->data(), buf->size());
            // If there was an error now, there will be an error later and we will remove
            // it from the list then.
        }
    }

    // For each of the report fields, see if we need it, and if so, execute the command
    // and report to those that care that we're doing it.
    for (const Section** section=SECTION_LIST; *section; section++) {
        const int id = (*section)->id;
        ALOGD("Taking incident report section %d '%s'", id, (*section)->name.string());

        if (this->args.containsSection(id)) {
            // Notify listener of starting
            for (ReportRequestSet::iterator it=batch.begin(); it!=batch.end(); it++) {
                if ((*it)->listener != NULL && (*it)->args.containsSection(id)) {
                    (*it)->listener->onReportSectionStatus(id,
                            IIncidentReportStatusListener::STATUS_STARTING);
                }
            }

            // Execute - go get the data and write it into the file descriptors.
            err = (*section)->Execute(&batch);
            if (err != NO_ERROR) {
                ALOGW("Incident section %s (%d) failed. Stopping report.",
                        (*section)->name.string(), id);
                goto done;
            }

            // Notify listener of starting
            for (ReportRequestSet::iterator it=batch.begin(); it!=batch.end(); it++) {
                if ((*it)->listener != NULL && (*it)->args.containsSection(id)) {
                    (*it)->listener->onReportSectionStatus(id,
                            IIncidentReportStatusListener::STATUS_FINISHED);
                }
            }
        }
    }

done:
    // Close the file.
    if (mainFd >= 0) {
        close(mainFd);
    }

    // Tell everyone that we're done.
    for (ReportRequestSet::iterator it=batch.begin(); it!=batch.end(); it++) {
        if ((*it)->listener != NULL) {
            if (err == NO_ERROR) {
                (*it)->listener->onReportFinished();
            } else {
                (*it)->listener->onReportFailed();
            }
        }
    }

    // Put the report into dropbox.
    if (needMainFd && err == NO_ERROR) {
        sp<DropBoxManager> dropbox = new DropBoxManager();
        Status status = dropbox->addFile(String16("incident"), mFilename, 0);
        ALOGD("Incident report done. dropbox status=%s\n", status.toString8().string());
        if (!status.isOk()) {
            return REPORT_NEEDS_DROPBOX;
        }

        // If the status was ok, delete the file. If not, leave it around until the next
        // boot or the next checkin. If the directory gets too big older files will
        // be rotated out.
        unlink(mFilename.c_str());
    }

    return REPORT_FINISHED;
}

/**
 * Create our output file and set the access permissions to -rw-rw----
 */
status_t
Reporter::create_file(int* fd)
{
    const char* filename = mFilename.c_str();

    *fd = open(filename, O_CREAT | O_TRUNC | O_RDWR, 0660);
    if (*fd < 0) {
        ALOGE("Couldn't open incident file: %s (%s)", filename, strerror(errno));
        return -errno;
    }

    // Override umask. Not super critical. If it fails go on with life.
    chmod(filename, 0660);

    if (chown(filename, AID_SYSTEM, AID_SYSTEM)) {
        ALOGE("Unable to change ownership of incident file %s: %s\n", filename, strerror(errno));
        status_t err = -errno;
        unlink(mFilename.c_str());
        return err;
    }

    return NO_ERROR;
}

// ================================================================================
Reporter::run_report_status_t
Reporter::upload_backlog()
{
    DIR* dir;
    struct dirent* entry;
    struct stat st;

    if ((dir = opendir(INCIDENT_DIRECTORY.string())) == NULL) {
        ALOGE("Couldn't open incident directory: %s", INCIDENT_DIRECTORY.string());
        return REPORT_NEEDS_DROPBOX;
    }

    String8 dirbase(INCIDENT_DIRECTORY + "/");
    sp<DropBoxManager> dropbox = new DropBoxManager();

    // Enumerate, count and add up size
    while ((entry = readdir(dir)) != NULL) {
        if (entry->d_name[0] == '.') {
            continue;
        }
        String8 filename = dirbase + entry->d_name;
        if (stat(filename.string(), &st) != 0) {
            ALOGE("Unable to stat file %s", filename.string());
            continue;
        }
        if (!S_ISREG(st.st_mode)) {
            continue;
        }

        Status status = dropbox->addFile(String16("incident"), filename.string(), 0);
        ALOGD("Incident report done. dropbox status=%s\n", status.toString8().string());
        if (!status.isOk()) {
            return REPORT_NEEDS_DROPBOX;
        }

        // If the status was ok, delete the file. If not, leave it around until the next
        // boot or the next checkin. If the directory gets too big older files will
        // be rotated out.
        unlink(filename.string());
    }

    closedir(dir);

    return REPORT_FINISHED;
}