package api

import (
	"io"
	"net/http"
	"net/url"
	"strings"

	"github.com/patrickmn/go-cache"
	"github.com/tidwall/gjson"
)

type Tag struct {
	Tag          string
	Display      string
	Sort         string
	PostCount    int64
	Posts        []Submission
	Background   string
	BackgroundId string
}

func (client *Client) FetchTag(tag string, sort string, page string) (Tag, error) {
	// Dots are automatically removed on Imgur, so more cache hits
	tag = strings.ReplaceAll(tag, ".", "")

	cacheData, found := client.Cache.Get(tag + sort + page + "-tag")
	if found {
		return cacheData.(Tag), nil
	}

	req, err := http.NewRequest("GET", "https://api.imgur.com/post/v1/posts/t/"+tag, nil)
	if err != nil {
		return Tag{}, err
	}

	q := req.URL.Query()
	q.Add("client_id", client.ClientID)
	q.Add("include", "cover")
	q.Add("page", page)

	switch sort {
	case "newest":
		q.Add("filter[window]", "week")
		q.Add("sort", "-time")
	case "best":
		q.Add("filter[window]", "all")
		q.Add("sort", "-top")
	case "popular":
	default:
		q.Add("filter[window]", "week")
		q.Add("sort", "-viral")
		sort = "popular"
	}

	req.URL.RawQuery = q.Encode()

	res, err := http.DefaultClient.Do(req)
	if err != nil {
		return Tag{}, err
	}

	body, err := io.ReadAll(res.Body)
	if err != nil {
		return Tag{}, err
	}

	data := gjson.Parse(string(body))

	posts := make([]Submission, 0)
	data.Get("posts").ForEach(
		func(key, value gjson.Result) bool {
			url, _ := url.Parse(strings.ReplaceAll(value.Get("url").String(), "https://imgur.com", ""))
			q := url.Query()
			q.Add("tag", tag+"."+sort+"."+page+"."+key.String())
			url.RawQuery = q.Encode()

			posts = append(posts, Submission{
				Id:    value.Get("id").String(),
				Title: value.Get("title").String(),
				Link:  url.String(),
				Cover: Media{
					Id:   value.Get("cover_id").String(),
					Type: value.Get("cover.type").String(),
					Url:  strings.ReplaceAll(value.Get("cover.url").String(), "https://i.imgur.com", ""),
				},
				Points:    value.Get("point_count").Int(),
				Upvotes:   value.Get("upvote_count").Int(),
				Downvotes: value.Get("downvote_count").Int(),
				Comments:  value.Get("comment_count").Int(),
				Views:     value.Get("view_count").Int(),
				IsAlbum:   value.Get("is_album").Bool(),
			})

			return true
		},
	)

	tagData := Tag{
		Tag:        tag,
		Display:    data.Get("display").String(),
		Sort:       sort,
		PostCount:  data.Get("post_count").Int(),
		Posts:      posts,
		Background: "/" + data.Get("background_id").String() + ".webp",
	}

	client.Cache.Set(tag+sort+page+"-tag", tagData, 4*cache.DefaultExpiration)
	return tagData, nil
}