/*
  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.
*/

#include <QVarLengthArray>
#include <QMutexLocker>
#include <QDateTime>
#include <QDir>
#include <QSemaphore>

#include <sys/inotify.h>
#include <stropts.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <errno.h>

#include "smdirwatcher.h"
#include "smtreeitem.h"
#include "helper.h"

extern int errno;

SmDirWatcher::SmDirWatcher(QObject *parent) : QThread(parent), mFd(0), mDescr(0) {
    mBufLen = 1024 * (sizeof(struct inotify_event) + 16);
    mINdata = new char[mBufLen];
    mFd = inotify_init();

    mCollector = new SmDataColletor(8, this);
    mSemFree = new QSemaphore(1024);
    mSemUsed = new QSemaphore;
    mDataQueue = new QQueue<QPair<QString, DWEvent> >();
    mCollector->init(mSemFree, mSemUsed, mDataQueue);
    mCollector->start();
}

SmDirWatcher::~SmDirWatcher(){
    if(mFd && mDescr){
        inotify_rm_watch(mFd, mDescr);
    }
    delete mINdata;
}

void SmDirWatcher::setDir(const QString &dir){
    if(mDescr){
        inotify_rm_watch(mFd, mDescr); //generates IN_IGNORE ???
    }
    /* mask rationale:
     * IN_DELETE_SELF cannot happen since we're only
     * watching one directory at all time.
     * We don't care about the other events
     */
    mDescr = inotify_add_watch(mFd, qPrintable(dir), IN_CLOSE_WRITE | IN_CREATE | IN_DELETE | IN_MODIFY | IN_MOVED_FROM | IN_MOVED_TO);
    mCurrent = dir;
    mSemFree->acquire();
    QPair<QString, DWEvent> c = qMakePair(dir, Populate);
    mDataQueue->enqueue(c);
    mSemUsed->release();
}

void SmDirWatcher::run(){
    int r = read(mFd, mINdata, mBufLen);
    if(r <= 0){
        return;
    }
    int i = 0;
    while(i < r){
        inotify_event *e = reinterpret_cast<inotify_event*>(&mINdata[i]);
        if((!e->len) || (e->mask & IN_IGNORED)){
            i += sizeof(inotify_event) + e->len;
            continue;
        }
        mSemFree->acquire();
        quint32 mask = e->mask;
        QString name = QString("%1/%2").arg(mCurrent).arg(e->name);
        DWEvent curEvent = None;
        if(mask & IN_CREATE || mask & IN_MOVED_TO){
            curEvent = Added;
        }
        if(mask & IN_DELETE || mask & IN_MOVED_FROM){
            curEvent = Deleted;
        }
        if(mask & IN_CLOSE_WRITE || e->mask & IN_MODIFY){
            curEvent = Modified;
        }
        QPair<QString, DWEvent> c = qMakePair(name, curEvent);
        mDataQueue->enqueue(c);
        mSemUsed->release();
        i += sizeof(inotify_event) + e->len;
    }
}

SmDataColletor::SmDataColletor(const int numFields, QObject *parent) : QThread(parent), mSemFree(0), mSemUsed(0), mDataQueue(0), mNumFields(numFields) {}

void SmDataColletor::init(QSemaphore *set, QSemaphore *get, QQueue<QPair<QString, SmDirWatcher::DWEvent> > *data){
    mSemFree = set;
    mSemUsed = get;
    mDataQueue = data;
}

void SmDataColletor::run(){
    forever {
        mSemUsed->acquire();
        QPair<QString, SmDirWatcher::DWEvent> cur = mDataQueue->dequeue();
        if(cur.second == SmDirWatcher::Populate){
            SmTreeItem *i = populate(cur.first);
            emit population(i);
            mSemFree->release();
            continue;

        }
        QFileInfo fi(cur.first);
        QList<QVariant> fd = fileData(fi);
        emit newData(fd, cur.second);
        mSemFree->release();
    }
}

SmTreeItem * SmDataColletor::populate(const QString &dir){
    SmTreeItem *retval = new SmTreeItem(mNumFields);
    QDir d = QDir(dir);
    foreach(QFileInfo fi, d.entryInfoList()){
        if(fi.fileName() == "."){
            continue;
        }
        QList<QVariant> data = fileData(fi);
        SmTreeItem *newItem = new SmTreeItem(data, retval);
        retval->appendChild(newItem);
    }
    return retval;
}

const QList<QVariant> SmDataColletor::fileData(const QFileInfo &fi) const{
    QList<QVariant> data;
    data << fi.fileName() << fi.size();
    QString mime = Helper::mimeType(fi.absoluteFilePath());
    data << mime;
    data << fi.lastModified();
    QList<QVariant> si = QList<QVariant>() << QVariant() << QVariant();
    if(mime.startsWith("video")){
        si = Helper::duration(fi.absoluteFilePath());
    }
    data << Helper::md5Sum(fi.absoluteFilePath());
    data << si << fi.absoluteFilePath();
    return data;
}