package main

import (
    "github.com/mmcdole/gofeed"
)

func (ctx* ServerContext) FeedFilter_published(feed PodcastConfig, doc gofeed.Feed) ([]*gofeed.Item, error) {
    merge := func(left []*gofeed.Item, right []*gofeed.Item) []*gofeed.Item {
        buffer := []*gofeed.Item{}
        idxl := 0
        idxr := 0
        for idxl < len(left) && idxr < len(right) {
            if (left[idxl].PublishedParsed.After(*right[idxr].PublishedParsed) && !feed.FilterDirAsc) ||
               (left[idxl].PublishedParsed.Before(*right[idxr].PublishedParsed) && feed.FilterDirAsc) {
                buffer = append(buffer, left[idxl])
                idxl++
            } else {
                buffer = append(buffer, right[idxr])
                idxr++
            }
        }
        for idxl < len(left) {
            buffer = append(buffer, left[idxl])
            idxl++
        }
        for idxr < len(right) {
            buffer = append(buffer, right[idxr])
            idxr++
        }
        return buffer
    }
    var sort func(items []*gofeed.Item) []*gofeed.Item
    sort = func(items []*gofeed.Item) []*gofeed.Item {
        if len(items) < 2 {
            return items
        } else {
            left := sort(items[:len(items)/2])
            right := sort(items[len(items)/2:])
            return merge(left, right)
        }
    }
    doc.Items = sort(doc.Items)[:feed.FilterLimit]
    return doc.Items, nil
}