import { Mapillary } from "./Mapillary"
import { WikimediaImageProvider } from "./WikimediaImageProvider"
import { Imgur } from "./Imgur"
import GenericImageProvider from "./GenericImageProvider"
import { ImmutableStore, Store, UIEventSource } from "../UIEventSource"
import ImageProvider, { ProvidedImage } from "./ImageProvider"
import { WikidataImageProvider } from "./WikidataImageProvider"
import Panoramax from "./Panoramax"
import { Utils } from "../../Utils"

/**
 * A generic 'from the interwebz' image picker, without attribution
 */
export default class AllImageProviders {
    private static dontLoadFromPrefixes = ["https://photos.app.goo.gl/"]

    /**
     * The 'genericImageProvider' is a fallback that scans various other tags for tags, unless the URL starts with one of the given prefixes
     */
    public static genericImageProvider = new GenericImageProvider([
        ...Imgur.defaultValuePrefix,
        ...WikimediaImageProvider.commonsPrefixes,
        ...Mapillary.valuePrefixes,
        ...AllImageProviders.dontLoadFromPrefixes,
        "Category:",
    ])

    private static imageAttributionSources: ImageProvider[] = [
        Imgur.singleton,
        Mapillary.singleton,
        WikidataImageProvider.singleton,
        WikimediaImageProvider.singleton,
        Panoramax.singleton,
        AllImageProviders.genericImageProvider,
    ]
    public static apiUrls: string[] = [].concat(
        ...AllImageProviders.imageAttributionSources.map((src) => src.apiUrls())
    )
    public static defaultKeys = [].concat(
        AllImageProviders.imageAttributionSources.map((provider) => provider.defaultKeyPrefixes)
    )
    private static providersByName = {
        imgur: Imgur.singleton,
        mapillary: Mapillary.singleton,
        wikidata: WikidataImageProvider.singleton,
        wikimedia: WikimediaImageProvider.singleton,
        panoramax: Panoramax.singleton,
    }

    public static byName(name: string) {
        return AllImageProviders.providersByName[name.toLowerCase()]
    }

    public static async selectBestProvider(key: string, value: string): Promise<ImageProvider> {
        for (const imageProvider of AllImageProviders.imageAttributionSources) {
            try {
                const extracted = await Promise.all(await imageProvider.ExtractUrls(key, value))
                if (extracted?.length > 0) {
                    return imageProvider
                }
            } catch (e) {
                console.warn("Provider gave an error while trying to determine a match:", e)
            }
        }

        return AllImageProviders.genericImageProvider
    }

    private static readonly _cachedImageStores: Record<string, Store<ProvidedImage[]>> = {}

    /**
     * Does a guess on the number of images that are probably there.
     * Will simply count all image tags
     *
     * AllImageProviders.estimateNumberOfImages({image:"abc", "mapillary": "123", "panoramax:0": "xyz"}) // => 3
     * AllImageProviders.estimateNumberOfImages({wikidata:"Q123", "wikipedia": "nl:xyz"}) // => 0
     *
     *
     */
    public static estimateNumberOfImages(
        tags: Record<string, string>,
        prefixes: string[] = undefined
    ): number {
        let count = 0

        const sources = [
            Imgur.singleton,
            Mapillary.singleton,
            Panoramax.singleton,
            AllImageProviders.genericImageProvider,
        ]
        const allPrefixes = Utils.Dedup(
            prefixes ?? [].concat(...sources.map((s) => s.defaultKeyPrefixes))
        )
        for (const prefix of allPrefixes) {
            for (const k in tags) {
                if (!tags[k]) {
                    continue
                }
                if (k === prefix || k.startsWith(prefix + ":")) {
                    count++
                    continue
                }
            }
        }
        return count
    }

    /**
     * Tries to extract all image data for this image. Cached on tags?.data?.id
     */
    public static loadImagesFor(
        tags: Store<Record<string, string>>,
        tagKey?: string[]
    ): Store<ProvidedImage[]> {
        if (tags?.data?.id === undefined) {
            return undefined
        }
        const id = tags?.data?.id
        const cachekey = id + (tagKey?.join(";") ?? "")
        if (this._cachedImageStores[cachekey]) {
            return this._cachedImageStores[cachekey]
        }

        const source = new UIEventSource([])
        const allSources: Store<ProvidedImage[]>[] = []
        for (const imageProvider of AllImageProviders.imageAttributionSources) {
            /*
                By default, 'GetRelevantUrls' uses the defaultKeyPrefixes.
                However, we override them if a custom image tag is set, e.g. 'image:menu'
               */
            const prefixes = tagKey ?? imageProvider.defaultKeyPrefixes
            const singleSource = tags.bindD((tags) => imageProvider.getRelevantUrls(tags, prefixes))
            allSources.push(singleSource)
            singleSource.addCallbackAndRunD((_) => {
                const all: ProvidedImage[] = [].concat(...allSources.map((source) => source.data))
                const dedup = Utils.DedupOnId(all, (i) => i?.id ?? i?.url)
                source.set(dedup)
            })
        }
        this._cachedImageStores[cachekey] = source
        return source
    }

    /**
     * Given a list of URLs, tries to detect the images. Used in e.g. the comments
     */
    public static loadImagesFrom(urls: string[]): Store<ProvidedImage[]> {
        const tags = {
            id: urls.join(";"),
        }
        for (let i = 0; i < urls.length; i++) {
            tags["image:" + i] = urls[i]
        }
        return this.loadImagesFor(new ImmutableStore(tags))
    }
}