package glance

import (
	"math"
	"sort"
	"time"
)

const twitchGqlEndpoint = "https://gql.twitch.tv/gql"
const twitchGqlClientId = "kimne78kx3ncx6brgo4mv6wki5h1ko"

type forumPost struct {
	Title           string
	DiscussionUrl   string
	TargetUrl       string
	TargetUrlDomain string
	ThumbnailUrl    string
	CommentCount    int
	Score           int
	Engagement      float64
	TimePosted      time.Time
	Tags            []string
	IsCrosspost     bool
}

type forumPostList []forumPost

const depreciatePostsOlderThanHours = 7
const maxDepreciation = 0.9
const maxDepreciationAfterHours = 24

func (p forumPostList) calculateEngagement() {
	var totalComments int
	var totalScore int

	for i := range p {
		totalComments += p[i].CommentCount
		totalScore += p[i].Score
	}

	numberOfPosts := float64(len(p))
	averageComments := float64(totalComments) / numberOfPosts
	averageScore := float64(totalScore) / numberOfPosts

	for i := range p {
		p[i].Engagement = (float64(p[i].CommentCount)/averageComments + float64(p[i].Score)/averageScore) / 2

		elapsed := time.Since(p[i].TimePosted)

		if elapsed < time.Hour*depreciatePostsOlderThanHours {
			continue
		}

		p[i].Engagement *= 1.0 - (math.Max(elapsed.Hours()-depreciatePostsOlderThanHours, maxDepreciationAfterHours)/maxDepreciationAfterHours)*maxDepreciation
	}
}

func (p forumPostList) sortByEngagement() {
	sort.Slice(p, func(i, j int) bool {
		return p[i].Engagement > p[j].Engagement
	})
}