module.exports = client => {
    const constant = require('./constant'),
        schedule = require('node-schedule'),
        { pick } = require('stream-json/filters/Pick'),
        { parser } = require('stream-json'),
        { streamArray } = require('stream-json/streamers/StreamArray'),
        { chain } = require('stream-chain'),
        size = 500,
        deleteDup = async () => {
            const count = { deleted: 0, total: 0, current: 0 }
            let lastsort = undefined, last = undefined
            await searchDup(count, lastsort, last)
        },
        searchDup = async (count, lastsort, last) => {
            count.current = 0
            const result = await client.search({
                index: constant.index,
                size: size,
                body: {
                    query: {
                        match_all: {}
                    },
                    sort: [{
                        "instance": {
                            "order": "asc"
                        },
                        "last": {
                            "order": "desc",
                            "numeric_type": "date_nanos",
                            "format": "strict_date_optional_time_nanos"
                        }
                    }],
                    search_after: lastsort
                }
            }, { asStream: true, meta: false }),
                pipeline = chain([
                    parser(),
                    pick({ filter: 'hits.hits' }),
                    streamArray(),
                    data => data.value
                ])
            pipeline.on('data', async data => {
                count.current++
                if (last && last.instance === data._source.instance) {
                    await client.delete({ index: constant.index, id: data._id })
                    count.deleted++
                    console.log('deleted ' + data._id + ': ' + data._source.instance)
                }
                else {
                    last = data._source
                }
                if (count.current === size) {
                    lastsort = data.sort
                }
            })
            pipeline.on('end', async () => {
                count.total += count.current
                if (count.current === size) {
                    await searchDup(count, lastsort, last)
                } else {
                    console.log('Index: ' + constant.index + ' - Total: ' + count.total + ' - Deleted: ' + count.deleted)
                }
            })
            result.pipe(pipeline)
        },
        job = schedule.scheduleJob('0 ' + constant.taskdeletedup + ' * * *', async () => {
            await deleteDup()
        })
}