# -*- coding: utf8 -*-

"""
This module contains functions which implements functionality necessary to run
general `fio`_ workloads as `k8s Jobs`_ in OCP/OCS cluster via workload
fixtures (see :py:mod:`ocs_ci.utility.workloadfixture`).

.. moduleauthor:: <NAME>

.. _`fio`: https://fio.readthedocs.io/en/latest/fio_doc.html
.. _`k8s Jobs`: https://kubernetes.io/docs/concepts/workloads/controllers/jobs-run-to-completion/
"""


import logging
import os
import textwrap
import time

import pytest
import yaml

from ocs_ci.framework import config
from ocs_ci.ocs import constants, ocp
from ocs_ci.ocs.exceptions import TimeoutExpiredError
from ocs_ci.ocs.exceptions import UnexpectedVolumeType
from ocs_ci.ocs.resources import pod
from ocs_ci.ocs.resources.objectconfigfile import ObjectConfFile
from ocs_ci.utility.utils import TimeoutSampler
from ocs_ci.utility.workloadfixture import measure_operation


logger = logging.getLogger(__name__)


def get_ceph_storage_stats(ceph_pool_name):
    """
    Get ceph storage utilization values from ``ceph df``: total STORED value
    and MAX AVAIL of given ceph pool, which are important for understanding
    how much space is already consumed and how much is still available.

    Args:
        ceph_pool_name (str): name of ceph pool where you want to write data

    Returns:
        tuple:
            int: sum of all ceph pool STORED values (Bytes)
            int: value of MAX AVAIL value of given ceph pool (Bytes)

    """
    ct_pod = pod.get_ceph_tools_pod()
    ceph_df_dict = ct_pod.exec_ceph_cmd(ceph_cmd="ceph df")
    ceph_pool = None
    ceph_total_stored = 0
    for pool in ceph_df_dict["pools"]:
        ceph_total_stored += pool["stats"]["stored"]
        if pool["name"] == ceph_pool_name:
            ceph_pool = pool
    if ceph_pool is None:
        logger.error(
            f"pool {ceph_pool_name} was not found "
            f"in output of `ceph df`: {ceph_df_dict}"
        )
    # If the following assert fail, the problem is either:
    #  - name of the pool has changed (when this happens before GA, it's
    #    likely ocs-ci bug, after the release it's a product bug),
    #  - pool is missing (likely a product bug)
    # either way, the fixture can't continue ...
    assert ceph_pool is not None, f"Pool: {ceph_pool_name} doesn't exist!"
    return ceph_total_stored, ceph_pool["stats"]["max_avail"]


def get_storageutilization_size(target_percentage, ceph_pool_name):
    """
    For the purpose of the workload storage utilization fixtures, get expected
    pvc_size based on STORED and MAX AVAIL values (as reported by `ceph df`)
    for given ceph pool and target utilization percentage.

    This is only approximate, and it won't work eg. if each pool has different
    configuration of replication.

    Args:
        target_percentage (float): target total utilization, eg. 0.5 for 50%
        ceph_pool_name (str): name of ceph pool where you want to write data

    Returns:
        int: pvc_size for storage utilization job (in GiB, rounded)

    """
    ceph_total_stored, max_avail = get_ceph_storage_stats(ceph_pool_name)
    # ... to compute PVC size (values in bytes)
    total = max_avail + ceph_total_stored  # Bytes
    max_avail_gi = max_avail / 2**30  # GiB
    logger.info(f"MAX AVAIL of {ceph_pool_name} is {max_avail_gi} Gi")
    target = total * target_percentage
    to_utilize = target - ceph_total_stored
    pvc_size = round(to_utilize / 2**30)  # GiB
    logger.info(
        f"to reach {target/2**30} Gi of total cluster utilization, "
        f"which is {target_percentage*100}% of the total capacity, "
        f"utilization job should request and fill {pvc_size} Gi volume"
    )
    return pvc_size


def fio_to_dict(fio_output):
    """ "
    Parse fio output and provide parsed dict it as a result.
    """
    fio_output_lines = fio_output.splitlines()
    line_num = 0
    for line_num, line in enumerate(fio_output_lines):
        if line == "{":
            break
        else:
            logger.info(line)
    fio_parseable_output = "\n".join(fio_output_lines[line_num:])
    try:
        fio_report = yaml.safe_load(fio_parseable_output)
    except yaml.parser.ParserError as ex:
        logger.error("json output from fio can't be parsed: %s", ex)
        raise ex
    return fio_report


def get_timeout(fio_min_mbps, pvc_size):
    """
    Compute how long we will let the job running while writing data to the
    volume.

    Args:
      fio_min_mbps (int): minimal write speed in MiB/s
      pvc_size (int): size of PVC in GiB, which will be used to writing

    Returns:
        int: write_timeout in seconds

    """
    # based on min. fio write speed of the enviroment ...
    logger.info("Assuming %.2f MB/s is a minimal write speed of fio.", fio_min_mbps)
    # ... we compute max. time we are going to wait for fio to write all data
    min_time_to_write_gb = 1 / (fio_min_mbps / 2**10)
    write_timeout = pvc_size * min_time_to_write_gb  # seconds
    logger.info(
        f"fixture will wait {write_timeout} seconds for the Job "
        f"to write {pvc_size} Gi data on OCS backed volume"
    )
    return write_timeout


def wait_for_job_completion(namespace, timeout, error_msg):
    """
    This is a WORKAROUND of particular ocsci design choices: I just wait
    for one pod in the namespace, and then ask for the pod again to get
    it's name (but it would be much better to just wait for the job to
    finish instead, then ask for a name of the successful pod and use it
    to get logs ...)

    Returns:
        str: name of Pod resource of the finished job

    """
    ocp_pod = ocp.OCP(kind="Pod", namespace=namespace)
    try:
        ocp_pod.wait_for_resource(
            resource_count=1,
            condition=constants.STATUS_COMPLETED,
            error_condition=constants.STATUS_ERROR,
            timeout=timeout,
            sleep=30,
        )
    except Exception as ex:
        # report some high level error as well in case of a timeout error
        if type(ex) == TimeoutExpiredError:
            logger.error(error_msg)
            ex.message = error_msg
        # fetch log(s) of any fio pod(s) in the job namespace
        pod_data = ocp_pod.get()
        for pod_dict in pod_data.get("items", []):
            try:
                pod_name = pod_dict["metadata"]["name"]
                output = ocp_pod.get_logs(pod_name)
                if len(output) == 0:
                    logger.error("Container log from pod '%s' is empty.", pod_name)
                else:
                    logger.error(
                        "Container log from pod '%s' follows:\n%s", pod_name, output
                    )
            except Exception:
                logger.exception(
                    "Container log from pod '%s' failed to be fetched.", pod_name
                )
        # reraise the exception
        raise (ex)

    # indentify pod of the completed job
    pod_data = ocp_pod.get()
    # explicit list of assumptions, if these assumptions are not met, the
    # code won't work and it either means that something went terrible
    # wrong or that the code needs to be changed
    assert pod_data["kind"] == "List"
    pod_dict = pod_data["items"][0]
    assert pod_dict["kind"] == "Pod"
    pod_name = pod_dict["metadata"]["name"]
    logger.info(f"Identified pod name of the finished Job: {pod_name}")

    return pod_name


def write_data_via_fio(fio_job_file, write_timeout, pvc_size, target_percentage):
    """
    Write data via fio Job (specified in ``tf`` tmp file) to reach desired
    utilization level, and keep this level for ``minimal_time`` seconds.
    """
    # unix timestamp before starting the job so that one can check status
    # prior the fio job run
    fio_job_start_ts = time.time()

    # deploy the fio Job to the cluster
    fio_job_file.create()

    # high level description of the problem, reported in case of a job failure
    # or timeout
    error_msg = (
        f"Job fio failed to write {pvc_size} Gi data on OCS backed "
        f"volume in expected time {write_timeout} seconds."
        " If the fio pod were still runing"
        " (see 'last actual status was' in some previous log message),"
        " this is caused either by"
        " severe product performance regression"
        " or by a misconfiguration of the clusterr, ping infra team."
    )
    pod_name = wait_for_job_completion(
        fio_job_file.project.namespace, write_timeout, error_msg
    )

    ocp_pod = ocp.OCP(kind="Pod", namespace=fio_job_file.project.namespace)
    fio_output = ocp_pod.get_logs(pod_name)

    # parse fio output
    fio_report = fio_to_dict(fio_output)

    logger.debug(fio_report)
    if fio_report is not None:
        disk_util = fio_report.get("disk_util")
        logger.info("fio disk_util stats: %s", disk_util)
    else:
        logger.warning("fio report is empty")

    # data which will be available to the test via:
    # fixture_name['result']
    result = {
        "fio_job_start": fio_job_start_ts,
        "fio": fio_report,
        "pvc_size": pvc_size,
        "target_p": target_percentage,
        "namespace": fio_job_file.project.namespace,
    }

    return result


def delete_fio_data(fio_job_file, delete_check_func):
    """
    Delete fio data by removing the fio job resource, with a wait to
    make sure date were reclaimed on the ceph level.
    """
    # make sure we communicate what is going to happen
    logger.info(f"going to delete {fio_job_file.name} Job")
    fio_job_file.delete()
    logger.info(
        f"going to wait a bit to make sure that "
        f"data written by {fio_job_file.name} Job are really deleted"
    )

    check_timeout = 660  # seconds
    check_sampler = TimeoutSampler(
        timeout=check_timeout, sleep=30, func=delete_check_func
    )
    finished_in_time = check_sampler.wait_for_func_status(result=True)
    if not finished_in_time:
        error_msg = (
            "it seems that the storage space was not reclaimed "
            f"within {check_timeout} seconds, "
            "this is most likely a product bug or misconfiguration"
        )
        logger.error(error_msg)
        raise Exception(error_msg)


def workload_fio_storageutilization(
    fixture_name,
    project,
    fio_pvc_dict,
    fio_job_dict,
    fio_configmap_dict,
    measurement_dir,
    tmp_path,
    target_percentage=None,
    target_size=None,
    with_checksum=False,
    keep_fio_data=False,
    minimal_time=480,
):
    """
    This function implements core functionality of fio storage utilization
    workload fixtures. This is necessary because we can't parametrize single
    general fixture over multiple parameters (it would mess with test case id
    and polarion test case tracking).

    It works as a workload fixture, as understood by
    :py:mod:`ocs_ci.utility.workloadfixture` module.

    When ``target_percentage`` is specified, the goal of the fixture is to fill
    whatever is left so that total cluster utilization reaches the target
    percentage. This means that in this mode, number of data written depends
    on both total capacity and current utilization. If the current storage
    utilization already exceeds the target, the test is skipped.

    On the other hand with ``target_size``, you can specify the size of data
    written by fio directly.

    Args:
        fixture_name (str): name of the fixture using this function (for
            logging and k8s object labeling purposes)
        project (ocs_ci.ocs.ocp.OCP): OCP object of project in which the Job is
            deployed, as created by ``project_factory`` or ``project`` fixture
        fio_pvc_dict (dict): PVC k8s struct for fio target volume
        fio_job_dict (dict): Job k8s struct for fio job
        fio_configmap_dict (dict): configmap k8s struct with fio config file
        measurement_dir (str): reference to a fixture which represents a
            directory where measurement results are stored, see also
            :py:func:`ocs_ci.utility.workloadfixture.measure_operation()`
        tmp_path (pathlib.PosixPath): reference to pytest ``tmp_path`` fixture
        target_percentage (float): target utilization as percentage wrt all
            usable OCS space, eg. 0.50 means a request to reach 50% of total
            OCS storage utilization (wrt usable space)
        target_size (int): target size of the PVC for fio to use, eg. 10 means
            a request for fio to write 10GiB of data
        with_checksum (bool): if true, sha1 checksum of the data written by
            fio is stored on the volume, and reclaim policy of the volume is
            changed to ``Retain`` so that the volume is not removed during test
            teardown for later verification runs
        keep_fio_data (bool): If true, keep the fio data after the fio
            storage utilization is completed. Else if false, deletes the fio data.
        minimal_time (int): Minimal number of seconds to monitor a system.
            (See more details in the function 'measure_operation')

    Returns:
        dict: measurement results with timestamps and other medatada from
            :py:func:`ocs_ci.utility.workloadfixture.measure_operation()`

    """
    val_err_msg = "Specify either target_size or target_percentage"
    if target_size is None and target_percentage is None:
        raise ValueError(
            val_err_msg + ", it's not clear how much storage space should be used."
        )
    if target_size is not None and target_percentage is not None:
        raise ValueError(val_err_msg + ", not both.")

    # TODO: move out storage class names
    if fixture_name.endswith("rbd"):
        storage_class_name = "ocs-storagecluster-ceph-rbd"
        ceph_pool_name = "ocs-storagecluster-cephblockpool"
    elif fixture_name.endswith("cephfs"):
        storage_class_name = "ocs-storagecluster-cephfs"
        ceph_pool_name = "ocs-storagecluster-cephfilesystem-data0"
    else:
        raise UnexpectedVolumeType("unexpected volume type, ocs-ci code is wrong")

    # make sure we communicate what is going to happen
    logger.info(
        (
            f"starting {fixture_name} fixture, "
            f"using {storage_class_name} storage class "
            f"backed by {ceph_pool_name} ceph pool"
        )
    )

    # log ceph mon_osd_*_ratio values for QE team to understand behaviour of
    # ceph cluster during high utilization levels (for expected values, consult
    # BZ 1775432 and check that there is no more recent BZ or JIRA in this
    # area)
    ceph_full_ratios = [
        "full_ratio",
        "backfillfull_ratio",
        "nearfull_ratio",
    ]
    ct_pod = pod.get_ceph_tools_pod()
    # As noted in ceph docs:
    # https://docs.ceph.com/docs/nautilus/rados/configuration/mon-config-ref/
    # we need to look for full ratio values in OSDMap of the cluster:
    # > These settings only apply during cluster creation. Afterwards they need
    # > to be changed in the OSDMap using ceph osd set-nearfull-ratio and ceph
    # > osd set-full-ratio
    logger.info("inspecting values of ceph *full ratios in osd map")
    osd_dump_dict = ct_pod.exec_ceph_cmd("ceph osd dump")
    for ceph_ratio in ceph_full_ratios:
        ratio_value = osd_dump_dict.get(ceph_ratio)
        if ratio_value is not None:
            logger.info(f"{ceph_ratio} is {ratio_value}")
        else:
            logger.warning(f"{ceph_ratio} not found in osd map")

    if target_size is not None:
        pvc_size = target_size
    else:
        pvc_size = get_storageutilization_size(target_percentage, ceph_pool_name)

    # If we are trying to utilize particular percentage of total OCS capacity
    # and current usage is already higher, the test will be skipped, because
    # the idea of tests reaching a particular total utilization is to do just
    # that, and the fixture can't provide expected assumptions to the test.
    # This skip is also easier to read in the test report than the actual
    # failure with negative pvc size.
    if pvc_size <= 0 and target_percentage is not None:
        skip_msg = (
            "current total storage utilization is too high, "
            f"the target utilization {target_percentage*100}% is already met"
        )
        logger.warning(skip_msg)
        pytest.skip(skip_msg)

    fio_conf = textwrap.dedent(
        """
        [simple-write]
        readwrite=write
        buffered=1
        blocksize=4k
        ioengine=libaio
        directory=/mnt/target
        nrfiles=8
        """
    )

    # When we ask for checksum to be generated for all files written in the
    # /mnt/target directory, we need to keep some space free so that the
    # checksum file would fit there. We overestimate this free space so that
    # it works both with CephFS and RBD volumes, as with RBD volumes actuall
    # usable capacity is smaller because of filesystem overhead (pvc size
    # defines size of a block device, on which local ext4 filesystem is
    # formatted).
    if with_checksum:
        # assume 4% fs overhead, and double to it make it safe
        fs_overhead = 0.08
        # size of file created by fio in MiB
        fio_size = int((pvc_size * (1 - fs_overhead)) * 2**10)
        fio_conf += f"size={fio_size}M\n"
    # Otherwise, we are tryting to write as much data as possible and fill the
    # persistent volume entirely.
    # For cephfs we can't use fill_fs because of BZ 1763808 (the process
    # will get *Disk quota exceeded* error instead of *No space left on
    # device* error).
    # On the other hand, we can't use size={pvc_size} for rbd, as we can't
    # write pvc_size bytes to a filesystem on a block device of {pvc_size}
    # size (obviously, some space is used by filesystem metadata).
    elif fixture_name.endswith("rbd"):
        fio_conf += "fill_fs=1\n"
    else:
        fio_conf += f"size={pvc_size}G\n"

    # When we ask for checksum to be generated for all files written in the
    # /mnt/target directory, we change the command of the container to run
    # both fio and sha1 checksum tool in the target directory. To do that,
    # we use '/bin/sh -c' hack.
    if with_checksum:
        container = fio_job_dict["spec"]["template"]["spec"]["containers"][0]
        fio_command = " ".join(container["command"])
        sha_command = (
            "sha1sum /mnt/target/simple-write.*"
            " > /mnt/target/fio.sha1sum"
            " 2> /mnt/target/fio.stderr"
        )
        shell_command = fio_command + " && " + sha_command
        container["command"] = ["/bin/bash", "-c", shell_command]

    # put the dicts together into yaml file of the Job
    fio_configmap_dict["data"]["workload.fio"] = fio_conf
    fio_pvc_dict["spec"]["storageClassName"] = storage_class_name
    fio_pvc_dict["spec"]["resources"]["requests"]["storage"] = f"{pvc_size}Gi"
    fio_objs = [fio_pvc_dict, fio_configmap_dict, fio_job_dict]
    fio_job_file = ObjectConfFile(fixture_name, fio_objs, project, tmp_path)

    fio_min_mbps = config.ENV_DATA["fio_storageutilization_min_mbps"]
    write_timeout = get_timeout(fio_min_mbps, pvc_size)

    test_file = os.path.join(measurement_dir, f"{fixture_name}.json")

    measured_op = measure_operation(
        lambda: write_data_via_fio(
            fio_job_file, write_timeout, pvc_size, target_percentage
        ),
        test_file,
        measure_after=True,
        minimal_time=minimal_time,
    )

    # we don't need to delete anything if this fixture has been already
    # executed
    if not measured_op["first_run"]:
        return measured_op

    # measure MAX AVAIL value just before reclamaion of data written by fio
    _, max_avail_before_delete = get_ceph_storage_stats(ceph_pool_name)

    def is_storage_reclaimed():
        """
        Check whether data created by the Job were actually deleted.
        """
        _, max_avail = get_ceph_storage_stats(ceph_pool_name)
        reclaimed_size = round((max_avail - max_avail_before_delete) / 2**30)
        logger.info(
            "%d Gi of %d Gi (PVC size) seems already reclaimed",
            reclaimed_size,
            pvc_size,
        )
        result = reclaimed_size >= pvc_size * 0.9
        if result:
            logger.info("Storage for the PVC was at least 90% reclaimed.")
        else:
            logger.info("Storage for the PVC was not yet reclaimed enough.")
        return result

    if with_checksum:
        # Let's get the name of the PV via the PVC.
        ocp_pvc = ocp.OCP(kind=constants.PVC, namespace=project.namespace)
        pvc_data = ocp_pvc.get()
        # Explicit list of assumptions, if these assumptions are not met, the
        # code won't work and it either means that something went terrible
        # wrong or that the code needs to be changed.
        assert pvc_data["kind"] == "List"
        assert len(pvc_data["items"]) == 1
        pvc_dict = pvc_data["items"][0]
        assert pvc_dict["kind"] == constants.PVC
        pv_name = pvc_dict["spec"]["volumeName"]
        logger.info("Identified PV of the finished fio Job: %s", pv_name)
        # We change reclaim policy of the volume, so that we can reuse it
        # later, while everyting but the volume will be deleted during project
        # teardown. Note that while a standard way of doing this would be via
        # custom storage class with redefined reclaim policy, we need to do
        # this on this single volume only here, so editing volume directly is
        # more straightforward.
        logger.info("Changing persistentVolumeReclaimPolicy of %s", pv_name)
        ocp_pv = ocp.OCP(kind=constants.PV)
        patch_success = ocp_pv.patch(
            resource_name=pv_name,
            params='{"spec":{"persistentVolumeReclaimPolicy":"Retain"}}',
        )
        if patch_success:
            logger.info("Reclaim policy of %s was changed.", pv_name)
        else:
            logger.error("Reclaim policy of %s failed to be changed.", pv_name)
        label = f"fixture={fixture_name}"
        ocp_pv.add_label(pv_name, label)
    else:
        # Without checksum, we just need to make sure that data were deleted
        # and wait for this to happen to avoid conflicts with tests executed
        # right after this one.
        if not keep_fio_data:
            delete_fio_data(fio_job_file, is_storage_reclaimed)
        else:
            logger.info("The fio data will be deleted during project teardown")

    return measured_op
