BUILDSTATS_BASE = "${TMPDIR}/buildstats/"

################################################################################
# Build statistics gathering.
#
# The CPU and Time gathering/tracking functions and bbevent inspiration
# were written by Christopher Larson.
#
################################################################################

def get_buildprocess_cputime(pid):
    with open("/proc/%d/stat" % pid, "r") as f:
        fields = f.readline().rstrip().split()
    # 13: utime, 14: stime, 15: cutime, 16: cstime
    return sum(int(field) for field in fields[13:16])

def get_process_cputime(pid):
    import resource
    with open("/proc/%d/stat" % pid, "r") as f:
        fields = f.readline().rstrip().split()
    stats = { 
        'utime'  : fields[13],
        'stime'  : fields[14], 
        'cutime' : fields[15], 
        'cstime' : fields[16],  
    }
    iostats = {}
    if os.path.isfile("/proc/%d/io" % pid):
        with open("/proc/%d/io" % pid, "r") as f:
            while True:
                i = f.readline().strip()
                if not i:
                    break
                i = i.split(": ")
                iostats[i[0]] = i[1]
    resources = resource.getrusage(resource.RUSAGE_SELF)
    childres = resource.getrusage(resource.RUSAGE_CHILDREN)
    return stats, iostats, resources, childres

def get_cputime():
    with open("/proc/stat", "r") as f:
        fields = f.readline().rstrip().split()[1:]
    return sum(int(field) for field in fields)

def set_timedata(var, d, server_time):
    d.setVar(var, server_time)

def get_timedata(var, d, end_time):
    oldtime = d.getVar(var, False)
    if oldtime is None:
        return
    return end_time - oldtime

def set_buildtimedata(var, d):
    import time
    time = time.time()
    cputime = get_cputime()
    proctime = get_buildprocess_cputime(os.getpid())
    d.setVar(var, (time, cputime, proctime))

def get_buildtimedata(var, d):
    import time
    timedata = d.getVar(var, False)
    if timedata is None:
        return
    oldtime, oldcpu, oldproc = timedata
    procdiff = get_buildprocess_cputime(os.getpid()) - oldproc
    cpudiff = get_cputime() - oldcpu
    end_time = time.time()
    timediff = end_time - oldtime
    if cpudiff > 0:
        cpuperc = float(procdiff) * 100 / cpudiff
    else:
        cpuperc = None
    return timediff, cpuperc

def write_task_data(status, logfile, e, d):
    bn = d.getVar('BUILDNAME', True)
    bsdir = os.path.join(d.getVar('BUILDSTATS_BASE', True), bn)
    with open(os.path.join(logfile), "a") as f:
        elapsedtime = get_timedata("__timedata_task", d, e.time)
        if elapsedtime:
            f.write(d.expand("${PF}: %s\n" % e.task))
            f.write(d.expand("Elapsed time: %0.2f seconds\n" % elapsedtime))
            cpu, iostats, resources, childres = get_process_cputime(os.getpid())
            if cpu:
                f.write("utime: %s\n" % cpu['utime'])
                f.write("stime: %s\n" % cpu['stime'])
                f.write("cutime: %s\n" % cpu['cutime'])
                f.write("cstime: %s\n" % cpu['cstime'])
            for i in iostats:
                f.write("IO %s: %s\n" % (i, iostats[i]))
            rusages = ["ru_utime", "ru_stime", "ru_maxrss", "ru_minflt", "ru_majflt", "ru_inblock", "ru_oublock", "ru_nvcsw", "ru_nivcsw"]
            for i in rusages:
                f.write("rusage %s: %s\n" % (i, getattr(resources, i)))
            for i in rusages:
                f.write("Child rusage %s: %s\n" % (i, getattr(childres, i)))
        if status is "passed":
            f.write("Status: PASSED \n")
        else:
            f.write("Status: FAILED \n")
        f.write("Ended: %0.2f \n" % e.time)

python run_buildstats () {
    import bb.build
    import bb.event
    import time, subprocess, platform

    bn = d.getVar('BUILDNAME', True)
    bsdir = os.path.join(d.getVar('BUILDSTATS_BASE', True), bn)
    taskdir = os.path.join(bsdir, d.getVar('PF', True))

    if isinstance(e, bb.event.BuildStarted):
        ########################################################################
        # If the kernel was not configured to provide I/O statistics, issue
        # a one time warning.
        ########################################################################
        if not os.path.isfile("/proc/%d/io" % os.getpid()):
            bb.warn("The Linux kernel on your build host was not configured to provide process I/O statistics. (CONFIG_TASK_IO_ACCOUNTING is not set)")

        ########################################################################
        # at first pass make the buildstats hierarchy and then
        # set the buildname
        ########################################################################
        bb.utils.mkdirhier(bsdir)
        set_buildtimedata("__timedata_build", d)
        build_time = os.path.join(bsdir, "build_stats")
        # write start of build into build_time
        with open(build_time, "a") as f:
            host_info = platform.uname()
            f.write("Host Info: ")
            for x in host_info:
                if x:
                    f.write(x + " ")
            f.write("\n")
            f.write("Build Started: %0.2f \n" % time.time())

    elif isinstance(e, bb.event.BuildCompleted):
        build_time = os.path.join(bsdir, "build_stats")
        with open(build_time, "a") as f:
            ########################################################################
            # Write build statistics for the build
            ########################################################################
            timedata = get_buildtimedata("__timedata_build", d)
            if timedata:
                time, cpu = timedata
                # write end of build and cpu used into build_time
                f.write("Elapsed time: %0.2f seconds \n" % (time))
                if cpu:
                    f.write("CPU usage: %0.1f%% \n" % cpu)

    if isinstance(e, bb.build.TaskStarted):
        set_timedata("__timedata_task", d, e.time)
        bb.utils.mkdirhier(taskdir)
        # write into the task event file the name and start time
        with open(os.path.join(taskdir, e.task), "a") as f:
            f.write("Event: %s \n" % bb.event.getName(e))
            f.write("Started: %0.2f \n" % e.time)

    elif isinstance(e, bb.build.TaskSucceeded):
        write_task_data("passed", os.path.join(taskdir, e.task), e, d)
        if e.task == "do_rootfs":
            bs = os.path.join(bsdir, "build_stats")
            with open(bs, "a") as f:
                rootfs = d.getVar('IMAGE_ROOTFS', True)
                if os.path.isdir(rootfs):
                    try:
                        rootfs_size = subprocess.check_output(["du", "-sh", rootfs],
                                stderr=subprocess.STDOUT).decode('utf-8')
                        f.write("Uncompressed Rootfs size: %s" % rootfs_size)
                    except subprocess.CalledProcessError as err:
                        bb.warn("Failed to get rootfs size: %s" % err.output.decode('utf-8'))

    elif isinstance(e, bb.build.TaskFailed):
        # Can have a failure before TaskStarted so need to mkdir here too
        bb.utils.mkdirhier(taskdir)
        write_task_data("failed", os.path.join(taskdir, e.task), e, d)
        ########################################################################
        # Lets make things easier and tell people where the build failed in
        # build_status. We do this here because BuildCompleted triggers no
        # matter what the status of the build actually is
        ########################################################################
        build_status = os.path.join(bsdir, "build_stats")
        with open(build_status, "a") as f:
            f.write(d.expand("Failed at: ${PF} at task: %s \n" % e.task))
}

addhandler run_buildstats
run_buildstats[eventmask] = "bb.event.BuildStarted bb.event.BuildCompleted bb.build.TaskStarted bb.build.TaskSucceeded bb.build.TaskFailed"