refactor: moved components to separate modules

`content.ts` is now half less than the size, exported functions can be unit tested

src/content/priceService.ts

@@ -0,0 +1,81 @@
+import { defindex_key, storage_priceprefix } from "./config"
+import { priceUsingPricesTF } from "./pricing/pricestf"
+import { getStorageValue, setStorageValue } from "./storage"
+import { logDebug, log } from "./utils/log"
+
+/** Pricing data for a given TF2 item. */
+export class ItemPriceData {
+	/** Item SKU. */
+	sku: string
+	/** Date updated. */
+	update: Date
+	/** TTL in milliseconds. */
+	ttl: number
+	/** Price in keys. */
+	keys: number
+	/** Price in refined metal. */
+	metal: number
+	/** Steam Community Market price. */
+	scmPrice: number
+
+	toString(): string {
+		return `Price for ${this.sku}, fetched ${this.update} (expires ${this.update.getTime() + this.ttl})\n` + 
+			JSON.stringify({
+				keys: this.keys,
+				metal: this.metal,
+				scmPrice: this.scmPrice
+			})
+	}
+}
+
+
+export async function fetchKeyPrice(token: string) {
+	return fetchPrice(token, defindex_key, 6, new Date(), 86400000)
+}
+
+/**
+ * Fetch a price for a given SKU, using cached values if available.
+ * @param token prices.tf access token.
+ * @param update Date retrieved.
+ * @param ttl Time to cache results in milliseconds. 30 minutes by default.
+ */
+export async function fetchPrice(token: string, defIndex: number, quality: number, update: Date = new Date(), ttl: number = 30 * 60 * 1000): Promise<ItemPriceData> {
+	return new Promise(async (resolve, reject) => {
+		const sku = defIndex.toString() + ";" + quality.toString();
+		var data: ItemPriceData | null
+
+		const cached = await getStorageValue(storage_priceprefix + sku, null)
+		if (cached != null && 'keys' in cached && 'metal' in cached) {
+			data = cached
+		}
+
+		if (!data || data.sku != sku || 'update' in data && 'ttl' in data && Date.now() > (new Date(data.update).getTime() + data.ttl)) {
+			logDebug(`Fetching price data for ${sku}`)
+			if(!token) {
+				reject(401)
+			}
+			data = new ItemPriceData()
+			data.sku = sku
+			data.update = update
+			data.ttl = ttl
+
+			try {
+				const response = await priceUsingPricesTF(token, defIndex, quality)
+				if (response) {
+					data.keys = response.keys
+					data.metal = response.metal
+				}
+			} catch (error) {
+				log(`Received ${error} error while pricing ${sku} using prices.tf`)
+				reject(error)
+			}
+
+			if ('metal' in data && 'keys' in data) {
+				await setStorageValue(storage_priceprefix + sku, data)
+			}
+		} else {
+			logDebug(`Using cached price data for ${sku}`)
+		}
+		resolve(data)
+	})
+}