import itertools
import logging
import sys
from time import sleep

import os
import re
import shutil
from sqlalchemy import func

import ckan.plugins as p
from ckan.plugins.toolkit import config

try:
    from collections import OrderedDict  # from python 2.7
except ImportError:
    from sqlalchemy.util import OrderedDict


log = logging.getLogger(__name__)


def update(identifiers, queue):
    from ckanext.archiver import lib
    for pkg_or_res, is_pkg, num_resources_for_pkg, pkg_for_res in \
            _get_packages_and_resources_in_args(identifiers, queue):
        if is_pkg:
            package = pkg_or_res
            log.info('Queuing dataset %s (%s resources) Q:%s', package.name, num_resources_for_pkg, queue)
            lib.create_archiver_package_task(package, queue)
            sleep(0.1)  # to try to avoid Redis getting overloaded
        else:
            resource = pkg_or_res
            package = pkg_for_res
            log.info('Queuing resource %s/%s', package.name, resource.id)
            lib.create_archiver_resource_task(resource, queue)
            sleep(0.05)  # to try to avoid Redis getting overloaded


def _get_packages_and_resources_in_args(identifiers, queue):
    '''Given identifies that specify one or more datasets or
    resources, it generates a list of those packages & resources with some
    basic properties.

    Returns a tuple:
       (pkg_or_res, is_pkg, num_resources_for_pkg, pkg_for_res)
       When is_pkg=True:
           pkg_or_res - package object
           num_resources_for_pkg - number of resources it has
           pkg_for_res - None
       When is_pkg=False:
           pkg_or_res - resource object
           num_resources_for_pkg - None
           pkg_for_res - package object relating to the given resource
    '''
    from ckan import model
    packages = []
    resources = []
    if identifiers:
        for identifier in identifiers:
            # try arg as a group id/name
            group = model.Group.get(identifier)
            if group:
                if group.is_organization:
                    packages.extend(
                        model.Session.query(model.Package)
                            .filter_by(owner_org=group.id))
                else:
                    packages.extend(group.packages(with_private=True))
                if not queue:
                    queue = 'bulk'
                continue
            # try arg as a package id/name
            pkg = model.Package.get(identifier)
            if pkg:
                packages.append(pkg)
                if not queue:
                    queue = 'priority'
                continue
            # try arg as a resource id
            res = model.Resource.get(identifier)
            if res:
                resources.append(res)
                if not queue:
                    queue = 'priority'
                continue
            else:
                log.error('Could not recognize as a group, package or resource: %r', identifier)
                sys.exit(1)
    else:
        # all packages
        pkgs = model.Session.query(model.Package) \
            .filter_by(state='active') \
            .order_by('name').all()
        packages.extend(pkgs)
        if not queue:
            queue = 'bulk'

        log.info('Datasets to archive: %d', len(packages))
    if resources:
        log.info('Resources to archive: %d', len(resources))
    if not (packages or resources):
        log.error('No datasets or resources to process')
        sys.exit(1)

    log.info('Queue: %s', queue)
    for package in packages:
        if p.toolkit.check_ckan_version(max_version='2.2.99'):
            # earlier CKANs had ResourceGroup
            pkg_resources = \
                [resource for resource in
                 itertools.chain.from_iterable(
                     (rg.resources_all
                      for rg in package.resource_groups_all)
                 )
                 if res.state == 'active']
        else:
            pkg_resources = \
                [resource for resource in package.resources_all
                 if resource.state == 'active']
        yield package, True, len(pkg_resources), None

    for resource in resources:
        if p.toolkit.check_ckan_version(max_version='2.2.99'):
            package = resource.resource_group.package
        else:
            package = resource.package
        yield resource, False, None, package


def update_test(identifiers, queue):
    from ckanext.archiver import tasks
    # Prevent it loading config again
    tasks.load_config = lambda x: None
    for pkg_or_res, is_pkg, num_resources_for_pkg, pkg_for_res in \
            _get_packages_and_resources_in_args(identifiers):
        if is_pkg:
            package = pkg_or_res
            log.info('Archiving dataset %s (%s resources)', package.name, num_resources_for_pkg)
            tasks._update_package(package.id, queue, log)
        else:
            resource = pkg_or_res
            package = pkg_for_res
            log.info('Queuing resource %s/%s', package.name, resource.id)
            tasks._update_resource(resource.id, queue, log)


def init():
    import ckan.model as model
    from ckanext.archiver.model import init_tables
    init_tables(model.meta.engine)


def view(package_ref=None):
    from ckan import model
    from ckanext.archiver.model import Archival

    r_q = model.Session.query(model.Resource).filter_by(state='active')
    print('Resources: %i total' % r_q.count())
    a_q = model.Session.query(Archival)
    print('Archived resources: %i total' % a_q.count())
    num_with_cache_url = a_q.filter(Archival.cache_url != '').count()
    print('                    %i with cache_url' % num_with_cache_url)
    last_updated_res = a_q.order_by(Archival.updated.desc()).first()
    print('Latest archival: %s' % (last_updated_res.updated.strftime('%Y-%m-%d %H:%M') if last_updated_res else '(no)'))

    if package_ref:
        pkg = model.Package.get(package_ref)
        print('Package %s %s' % (pkg.name, pkg.id))
        for res in pkg.resources:
            print('Resource %s' % res.id)
            for archival in a_q.filter_by(resource_id=res.id):
                print('* %r' % archival)


def clean_status():
    from ckan import model
    from ckanext.archiver.model import Archival

    print('Before:')
    view()

    q = model.Session.query(Archival)
    q.delete()
    model.Session.commit()

    print('After:')
    view()


def clean_cached_resources():
    from ckan import model
    from ckanext.archiver.model import Archival

    print('Before:')
    view()

    q = model.Session.query(Archival).filter(Archival.cache_url != '')
    archivals = q.all()
    num_archivals = len(archivals)
    progress = 0
    for archival in archivals:
        archival.cache_url = None
        archival.cache_filepath = None
        archival.size = None
        archival.mimetype = None
        archival.hash = None
        progress += 1
        if progress % 1000 == 0:
            print('Done %i/%i' % (progress, num_archivals))
            model.Session.commit()
    model.Session.commit()
    model.Session.remove()

    print('After:')
    view()


def report(output_file, delete=False):
    """
        Generates a report containing orphans (either files or resources)
        """
    import csv
    from ckan import model

    archive_root = config.get('ckanext-archiver.archive_dir')
    if not archive_root:
        log.error("Could not find archiver root")
        return

    # We'll use this to match the UUID part of the path
    uuid_re = re.compile(".*([0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}).*")

    not_cached_active = 0
    not_cached_deleted = 0
    file_not_found_active = 0
    file_not_found_deleted = 0
    perm_error = 0
    file_no_resource = 0

    with open(output_file, "w") as f:
        writer = csv.writer(f)
        writer.writerow(["Resource ID", "Filepath", "Problem"])
        resources = {}
        for resource in model.Session.query(model.Resource).all():
            resources[resource.id] = True

            # Check the resource's cached_filepath
            fp = resource.extras.get('cache_filepath')
            if fp is None:
                if resource.state == 'active':
                    not_cached_active += 1
                else:
                    not_cached_deleted += 1
                writer.writerow([resource.id, str(resource.extras), "Resource not cached: {0}".format(resource.state)])
                continue

            # Check that the cached file is there and readable
            if not os.path.exists(fp):
                if resource.state == 'active':
                    file_not_found_active += 1
                else:
                    file_not_found_deleted += 1

                writer.writerow([resource.id, fp.encode('utf-8'), "File not found: {0}".format(resource.state)])
                continue

            try:
                os.stat(fp)
            except OSError:
                perm_error += 1
                writer.writerow([resource.id, fp.encode('utf-8'), "File not readable"])
                continue

        # Iterate over the archive root and check each file by matching the
        # resource_id part of the path to the resources dict
        for root, _, files in os.walk(archive_root):
            for filename in files:
                archived_path = os.path.join(root, filename)
                m = uuid_re.match(archived_path)
                if not m:
                    writer.writerow([resource.id, archived_path, "Malformed path (no UUID)"])
                    continue

                if not resources.get(m.groups(0)[0].strip(), False):
                    file_no_resource += 1

                    if delete:
                        try:
                            os.unlink(archived_path)
                            log.info("Unlinked {0}".format(archived_path))
                            os.rmdir(root)
                            log.info("Unlinked {0}".format(root))
                            writer.writerow([m.groups(0)[0], archived_path, "Resource not found, file deleted"])
                        except Exception as e:
                            log.error("Failed to unlink {0}: {1}".format(archived_path, e))
                    else:
                        writer.writerow([m.groups(0)[0], archived_path, "Resource not found"])

                    continue

    print("General info:")
    print("  Permission error reading file: {0}".format(perm_error))
    print("  file on disk but no resource: {0}".format(file_no_resource))
    print("  Total resources: {0}".format(model.Session.query(model.Resource).count()))
    print("Active resource info:")
    print("  No cache_filepath: {0}".format(not_cached_active))
    print("  cache_filepath not on disk: {0}".format(file_not_found_active))
    print("Deleted resource info:")
    print("  No cache_filepath: {0}".format(not_cached_deleted))
    print("  cache_filepath not on disk: {0}".format(file_not_found_deleted))


def migrate():
    """ Adds any missing columns to the database table for Archival by
        checking the schema and adding those that are missing.

        If you wish to add a column, add the column name and sql
        statement to MIGRATIONS_ADD which will check that the column is
        not present before running the query.

        If you wish to modify or delete a column, add the column name and
        query to the MIGRATIONS_MODIFY which only runs if the column
        does exist.
        """
    from ckan import model

    MIGRATIONS_ADD = OrderedDict({
        "etag": "ALTER TABLE archival ADD COLUMN etag character varying",
        "last_modified": "ALTER TABLE archival ADD COLUMN last_modified character varying"
    })

    MIGRATIONS_MODIFY = OrderedDict({
    })

    q = "select column_name from INFORMATION_SCHEMA.COLUMNS where table_name = 'archival';"
    current_cols = list([m[0] for m in model.Session.execute(q)])
    for k, v in MIGRATIONS_ADD.items():
        if k not in current_cols:
            log.info(u"Adding column '{0}'".format(k))
            log.info(u"Executing '{0}'".format(v))
            model.Session.execute(v)
            model.Session.commit()

    for k, v in MIGRATIONS_MODIFY.items():
        if k in current_cols:
            log.info(u"Removing column '{0}'".format(k))
            log.info(u"Executing '{0}'".format(v))
            model.Session.execute(v)
            model.Session.commit()
    log.info("Migrations complete")


def migrate_archiver_dirs():
    from ckan import model
    from ckan.logic import get_action

    site_user = get_action('get_site_user')(
        {'model': model, 'ignore_auth': True, 'defer_commit': True}, {}
    )

    site_url_base = config['ckanext-archiver.cache_url_root'].rstrip('/')
    old_dir_regex = re.compile(r'(.*)/([a-f0-9\-]+)/([^/]*)$')
    new_dir_regex = re.compile(r'(.*)/[a-f0-9]{2}/[a-f0-9\-]{36}/[^/]*$')
    for resource in model.Session.query(model.Resource). \
            filter(model.Resource.state != model.State.DELETED):
        if not resource.cache_url or resource.cache_url == 'None':
            continue
        if new_dir_regex.match(resource.cache_url):
            print('Resource with new url already: %s' % resource.cache_url)
            continue
        match = old_dir_regex.match(resource.cache_url)
        if not match:
            print('ERROR Could not match url: %s' % resource.cache_url)
            continue
        url_base, res_id, filename = match.groups()
        # check the package isn't deleted
        # Need to refresh the resource's session
        resource = model.Session.query(model.Resource).get(resource.id)
        if p.toolkit.check_ckan_version(max_version='2.2.99'):
            package = None
            if resource.resource_group:
                package = resource.resource_group.package
        else:
            package = resource.package

        if package and package.state == model.State.DELETED:
            print('Package is deleted')
            continue

        if url_base != site_url_base:
            print('ERROR Base URL is incorrect: %r != %r' % (url_base, site_url_base))
            continue

        # move the file
        filepath_base = config['ckanext-archiver.archive_dir']
        old_path = os.path.join(filepath_base, resource.id)
        new_dir = os.path.join(filepath_base, resource.id[:2])
        new_path = os.path.join(filepath_base, resource.id[:2], resource.id)
        new_filepath = os.path.join(new_path, filename)
        if not os.path.exists(new_dir):
            os.mkdir(new_dir)
        if os.path.exists(new_path) and not os.path.exists(old_path):
            print('File already moved: %s' % new_path)
        else:
            print('File: "%s" -> "%s"' % (old_path, new_path))
            try:
                shutil.move(old_path, new_path)
            except IOError as e:
                print('ERROR moving resource: %s' % e)
                continue

        # change the cache_url and cache_filepath
        new_cache_url = '/'.join((url_base, res_id[:2], res_id, filename))
        print('cache_filepath: "%s" -> "%s"' % (resource.extras.get('cache_filepath'), new_filepath))
        print('cache_url: "%s" -> "%s"' % (resource.cache_url, new_cache_url))
        context = {'model': model, 'user': site_user['name'], 'ignore_auth': True, 'session': model.Session}
        data_dict = {'id': resource.id}
        res_dict = get_action('resource_show')(context, data_dict)
        res_dict['cache_filepath'] = new_filepath
        res_dict['cache_url'] = new_cache_url
        data_dict = res_dict
        result = get_action('resource_update')(context, data_dict)
        if result.get('id') == res_id:
            print('Successfully updated resource')
        else:
            print('ERROR updating resource: %r' % result)


def size_report():
    from ckan import model
    from ckanext.archiver.model import Archival
    kb = 1024
    mb = 1024*1024
    gb = pow(1024, 3)
    size_bins = [
        (kb, '<1 KB'), (10*kb, '1-10 KB'), (100*kb, '10-100 KB'),
        (mb, '100 KB - 1 MB'), (10*mb, '1-10 MB'), (100*mb, '10-100 MB'),
        (gb, '100 MB - 1 GB'), (10*gb, '1-10 GB'), (100*gb, '10-100 GB'),
        (gb*gb, '>100 GB'),
    ]
    previous_bin = (0, '')
    counts = []
    total_sizes = []
    print('{:>15}{:>10}{:>20}'.format(
        'file size', 'no. files', 'files size (bytes)'))
    for size_bin in size_bins:
        q = model.Session.query(Archival) \
            .filter(Archival.size > previous_bin[0]) \
            .filter(Archival.size <= size_bin[0]) \
            .filter(Archival.cache_filepath != '') \
            .join(model.Resource,
                  Archival.resource_id == model.Resource.id) \
            .filter(model.Resource.state != 'deleted') \
            .join(model.Package,
                  Archival.package_id == model.Package.id) \
            .filter(model.Package.state != 'deleted')
        count = q.count()
        counts.append(count)
        total_size = model.Session.query(func.sum(Archival.size)) \
            .filter(Archival.size > previous_bin[0]) \
            .filter(Archival.size <= size_bin[0]) \
            .filter(Archival.cache_filepath != '') \
            .join(model.Resource,
                  Archival.resource_id == model.Resource.id) \
            .filter(model.Resource.state != 'deleted') \
            .join(model.Package,
                  Archival.package_id == model.Package.id) \
            .filter(model.Package.state != 'deleted') \
            .all()[0][0]
        total_size = int(total_size or 0)
        total_sizes.append(total_size)
        print('{:>15}{:>10,}{:>20,}'.format(size_bin[1], count, total_size))
        previous_bin = size_bin
    print('Totals: {:,} {:,}'.format(sum(counts), sum(total_sizes)))


def delete_files_larger_than_max_content_length():
    from ckan import model
    from ckanext.archiver.model import Archival
    from ckanext.archiver import default_settings as settings
    max_size = settings.MAX_CONTENT_LENGTH
    archivals = model.Session.query(Archival) \
        .filter(Archival.size > max_size) \
        .filter(Archival.cache_filepath != '') \
        .all()
    total_size = int(model.Session.query(func.sum(Archival.size))
                     .filter(Archival.size > max_size)
                     .all()[0][0] or 0)
    print('{} archivals above the {:,} threshold with total size {:,}'.format(
        len(archivals), max_size, total_size))
    input('Press Enter to DELETE them')
    for archival in archivals:
        print('Deleting %r' % archival)
        resource = model.Resource.get(archival.resource_id)
        if resource.state == 'deleted':
            print('Nothing to delete - Resource is deleted - deleting archival')
            model.Session.delete(archival)
            model.Session.commit()
            model.Session.flush()
            continue
        pkg = model.Package.get(archival.package_id)
        if pkg.state == 'deleted':
            print('Nothing to delete - Dataset is deleted - deleting archival')
            model.Session.delete(archival)
            model.Session.commit()
            model.Session.flush()
            continue
        filepath = archival.cache_filepath
        if not os.path.exists(filepath):
            print('Skipping - file not on disk')
            continue
        try:
            os.unlink(filepath)
        except OSError:
            print('ERROR deleting %s' % filepath.decode('utf8'))
        else:
            archival.cache_filepath = None
            model.Session.commit()
            model.Session.flush()
            print('..deleted %s' % filepath.decode('utf8'))