discordBots/cmd/dealsbot/api/steam.go

package api

import (
	"encoding/json"
	"fmt"
	"golang.org/x/net/html"
	"io"
	"log/slog"
	"net/http"
	"regexp"
)

type SteamStruct struct {
	url      string
	baseUrl  string
	apiUrl   string
	idPrefix string
	headers  map[string]string
	deals    DealsMap
	logger   *slog.Logger
}

func NewSteamApi(logger *slog.Logger) SteamStruct {
	steam := SteamStruct{
		url:      "https://store.steampowered.com/search/results?force_infinite=1&maxprice=free&specials=1",
		baseUrl:  "https://store.steampowered.com/app/",
		apiUrl:   "https://store.steampowered.com/api/appdetails?appids=",
		idPrefix: "steam-",
		headers:  make(map[string]string),
		deals:    make(map[string]Deal),
		logger:   logger,
	}
	steam.headers["Accept-Language"] = "en"
	steam.headers["User-Agent"] = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:93.0) Gecko/20100101 Firefox/93.0"
	return steam
}

type steamApiBodyGame struct {
	Success bool `json:"success"`
	Data    struct {
		Type          string `json:"type"`
		Name          string `json:"name"`
		IsFree        bool   `json:"is_free"`
		PriceOverview struct {
			Currency         string `json:"currency"`
			Initial          int    `json:"initial"`
			Final            int    `json:"final"`
			DiscountPercent  int    `json:"discount_percent"`
			InitialFormatted string `json:"initial_formatted"`
			FinalFormatted   string `json:"final_formatted"`
		} `json:"price_overview"`
		Platforms struct {
			Windows bool `json:"windows"`
			Mac     bool `json:"mac"`
			Linux   bool `json:"linux"`
		} `json:"platforms"`
	} `json:"data"`
}

type steamApiBody map[string]steamApiBodyGame

func (e SteamStruct) Load() error {
	client := &http.Client{}
	reqStore, err := http.NewRequest("GET", e.url, nil)
	if err != nil {
		return err
	}

	for key, value := range e.headers {
		reqStore.Header.Set(key, value)
	}

	resStore, err := client.Do(reqStore)
	if err != nil {
		return err
	}
	bodyStore := html.NewTokenizer(resStore.Body)

	// could also search over each #search_resultsRows element instead of regex
	regexAppid, err := regexp.Compile(`https://store\.steampowered\.com/app/(\d+)`)
	if err != nil {
		return err
	}

	var appIDs []string
	func() {

		for {
			tt := bodyStore.Next()

			switch {
			case tt == html.ErrorToken:
				// file end or error
				return
			case tt == html.StartTagToken:
				t := bodyStore.Token()
				if t.Data != "a" {
					continue
				}
				for _, a := range t.Attr {
					if a.Key != "href" {
						continue
					}
					appID := regexAppid.FindStringSubmatch(a.Val)
					if len(appID) < 1 {
						continue
					}
					appIDs = append(appIDs, appID[1])
				}
			}
		}
	}()

	for _, appID := range appIDs {
		reqApi, err := http.NewRequest("GET", fmt.Sprintf("%v%v", e.apiUrl, appID), nil)
		if err != nil {
			return err
		}

		for key, value := range e.headers {
			reqApi.Header.Set(key, value)
		}

		resApi, err := client.Do(reqApi)
		if err != nil {
			return err
		}
		bodyApi, err := io.ReadAll(resApi.Body)
		if err != nil {
			return err
		}
		var data steamApiBody
		err = json.Unmarshal(bodyApi, &data)
		if err != nil {
			return err
		}
		if game, ok := data[appID]; ok {
			if game.Data.Type != "game" {
				continue
			}
			id := fmt.Sprintf("%v%v", e.idPrefix, appID)
			title := game.Data.Name
			url := fmt.Sprintf("%v%v", e.baseUrl, appID)

			e.deals[id] = Deal{
				Id:    id,
				Title: title,
				Url:   url,
			}
		}
	}

	return nil
}

func (e SteamStruct) Get() []Deal {
	var deals []Deal
	for _, deal := range e.deals {
		deals = append(deals, deal)
	}
	return deals
}