drilldownFieldNames = {
    'drilldown.norm.date.year':       {'en':'Year', 'nl':'Jaar'},
    'drilldown.norm.date.decennium':  {'en':'Decennium', 'nl':'Decennium'},
    'drilldown.norm.date.centennium': {'en':'Centennium', 'nl':'Centennium'},

    'drilldown.norm.name.oneinitial': {'en':'Name', 'nl':'Naam'},
    'drilldown.norm.name.lastname':   {'en':'Top 10 Names', 'nl':'Top 10 Namen'},

    'drilldown.meta.repository.id':   {'en':'Repository', 'nl':'Repository'},
    'drilldown.meta.repository.repositoryGroupId':   {'en':'Source', 'nl':'Bron'},

    'drilldown.mods.classification':   {'en':'Classification', 'nl':'Classificatie'},
    'drilldown.mods.genre':           {'en':'Genre', 'nl':'Genre'},
    'drilldown.mods.language.languageTerm': {'en':'Language', 'nl':'Taal'},
    'drilldown.mods.relatedItem.titleInfo.title': {'en':'Journal/series', 'nl':'Tijdschrift/reeks'},
    'drilldown.mods.subject.topic':   {'en':'Subject', 'nl':'Onderwerp'}
}

drilldownFields = [
#####(field, number, sorted)#####
##### number == 0: all items? don't understand how number works; nothing is done with number
    #('drilldown.mods.name.namePart', 20, False),
    #('drilldown.norm.name.oneinitial', 20, False),
    ('drilldown.meta.repository.id',                 10, False),
    ('drilldown.meta.repository.repositoryGroupId',  10, False),
    ('drilldown.mods.classification',                10, False),
    ('drilldown.mods.genre',                          0, False),
    ('drilldown.mods.language.languageTerm',         10, False),
    ('drilldown.mods.relatedItem.titleInfo.title',   10, False),
    ('drilldown.mods.subject.topic',                 10, False)
]

def fieldAndTermSplit(fieldAndTerm):
    return fieldAndTerm.split(':', 1)

def fieldAndTermJoin(field, term):
    return '%s:%s' % (field, term)

def shrink(aString, maxLength=160):
    if len(aString) > maxLength:
        return aString[:maxLength] + '...'
    return aString

def createDrilldownQuery(drilldownArgs, httpQuery):
    newArguments = [('query', httpQuery)]
    for existing in drilldownArgs:
        newArguments.append(('drilldown', existing))
    return urlencode(newArguments)

def main(hits, httpQuery, arguments, path='', *args, **kwargs):
    language = path.startswith('/en/') and 'en' or 'nl'
    yield '<div id="drilldownresults">'

    selectedFacets = arguments.get('drilldown', [])
    if selectedFacets:
        yield '<div id="drilldownselection">'
        yield '<p>%s</p>' % {'nl':'Geselecteerde facetten', 'en':'Selected Facets'}[language]
        yield '<ul class="selectedFacets">'
        for drilldownItem in selectedFacets:
            fieldName, value = fieldAndTermSplit(drilldownItem)
            drilldownArgs = set(selectedFacets)
            drilldownArgs.remove(drilldownItem)

            label = drilldownFieldNames.get(fieldName, {'en':fieldName, 'nl':fieldName})[language]

            query = createDrilldownQuery(drilldownArgs, httpQuery)
            yield '<li><a href="?%s" title="%s">[-] %s: %s</a></li>' % (query, escapeHtml(value), label, escapeHtml( shrink(value, 20)))
        yield '</ul>'
        yield '</div>'

    yield '<div id="drilldownfields">'
    drilldownResults = any.drilldown(hits.bitMatrixRow(), drilldownFields)
    drilldownResultsAsDict = dict(drilldownResults)
    for fieldName, number, sorted in drilldownFields:
        termCounts = drilldownResultsAsDict.get(fieldName,[])
        label = drilldownFieldNames.get(fieldName, {'en':fieldName, 'nl':fieldName})[language]
        if termCounts == []:
            continue
        yield '<p>%s</p>' % label
        yield '<ul>'
        for term, count in termCounts:
            drilldownArgs = set(arguments.get('drilldown', []) + [fieldAndTermJoin(fieldName, term)])
            query = createDrilldownQuery(drilldownArgs, httpQuery)
            yield '<li><a href="?%s" title="%s">%s</a>: %s</li>' % (query, escapeHtml(term), shrink(term, 20), count)
        yield '</ul>'

    multilevelResults = any.multiLevelDrilldown(hits.bitMatrixRow(), ['date', 'author'])
    for (fieldName, levelField), termCounts in multilevelResults:
        label = drilldownFieldNames.get(levelField, {'en':levelField, 'nl':levelField})[language]
        yield '<p>%s</p>' % label
        yield '<ul>'
        for term, count in termCounts:
            drilldownArgs = set(arguments.get('drilldown', []) + [fieldAndTermJoin(levelField, term)])
            query = createDrilldownQuery(drilldownArgs, httpQuery)
            yield '<li><a href="?%s" title="%s">%s</a>: %s</li>' % (query, escapeHtml(term), shrink(term, 20), count)
        yield '</ul>'
    yield '</div>'
    yield '</div>'