import ThemeConfig, { MinimalThemeInformation } from "../../Models/ThemeConfig/ThemeConfig"
import { Store } from "../UIEventSource"
import UserRelatedState from "../State/UserRelatedState"
import { Utils } from "../../Utils"
import Locale from "../../UI/i18n/Locale"
import themeOverview from "../../assets/generated/theme_overview.json"
import LayerSearch from "./LayerSearch"
import SearchUtils from "./SearchUtils"
import { OsmConnection } from "../Osm/OsmConnection"

type ThemeSearchScore = {
    theme: MinimalThemeInformation
    lowest: number
    perLayer?: Record<string, number>
    other: number
}

export default class ThemeSearch {
    public static readonly officialThemes: {
        themes: MinimalThemeInformation[]
        layers: Record<string, Record<string, string[]>>
    } = <any>themeOverview
    public static readonly officialThemesById: Map<string, MinimalThemeInformation> = new Map<
        string,
        MinimalThemeInformation
    >()
    static {
        for (const th of ThemeSearch.officialThemes.themes ?? []) {
            ThemeSearch.officialThemesById.set(th.id, th)
        }
    }

    private readonly _knownHiddenThemes: Store<Set<string>>
    private readonly _layersToIgnore: string[]
    private readonly _otherThemes: MinimalThemeInformation[]

    constructor(state: { osmConnection: OsmConnection; theme: ThemeConfig }) {
        this._layersToIgnore = state.theme.layers.filter((l) => l.isNormal()).map((l) => l.id)
        this._knownHiddenThemes = UserRelatedState.initDiscoveredHiddenThemes(
            state.osmConnection
        ).map((list) => new Set(list))
        this._otherThemes = ThemeSearch.officialThemes.themes.filter(
            (th) => th.id !== state.theme.id
        )
    }

    public search(query: string, limit: number, threshold: number = 3): MinimalThemeInformation[] {
        if (query.length < 1) {
            return []
        }
        const sorted = ThemeSearch.sortedByLowestScores(
            query,
            this._otherThemes,
            this._layersToIgnore
        )
        return sorted
            .filter((sorted) => sorted.lowest < threshold)
            .map((th) => th.theme)
            .filter((th) => !th.hideFromOverview || this._knownHiddenThemes.data.has(th.id))
            .slice(0, limit)
    }

    public static createUrlFor(layout: { id: string }, state?: { layoutToUse?: { id } }): string {
        if (layout === undefined) {
            return undefined
        }
        if (layout.id === undefined) {
            console.error("ID is undefined for layout", layout)
            return undefined
        }

        if (layout.id === state?.layoutToUse?.id) {
            return undefined
        }

        let path = window.location.pathname
        // Path starts with a '/' and contains everything, e.g. '/dir/dir/page.html'
        path = path.substr(0, path.lastIndexOf("/"))
        // Path will now contain '/dir/dir', or empty string in case of nothing
        if (path === "") {
            path = "."
        }

        let linkPrefix = `${path}/${layout.id.toLowerCase()}.html?`
        if (location.hostname === "localhost" || location.hostname === "127.0.0.1") {
            linkPrefix = `${path}/theme.html?layout=${layout.id}&`
        }

        if (layout.id.startsWith("http://") || layout.id.startsWith("https://")) {
            linkPrefix = `${path}/theme.html?userlayout=${layout.id}&`
        }

        return `${linkPrefix}`
    }

    /**
     * Returns a score based on textual search
     *
     * Note that, if `query.length < 3`, layers are _not_ searched because this takes too much time
     * @param query
     * @param themes
     * @param ignoreLayers
     * @private
     */
    private static scoreThemes(
        query: string,
        themes: MinimalThemeInformation[],
        ignoreLayers: string[] = undefined
    ): Record<string, ThemeSearchScore> {
        if (query?.length < 1) {
            return undefined
        }
        themes = Utils.NoNullInplace(themes)

        let options: { blacklist: Set<string> } = undefined
        if (ignoreLayers?.length > 0) {
            options = { blacklist: new Set(ignoreLayers) }
        }
        const layerScores = query.length < 3 ? {} : LayerSearch.scoreLayers(query, options)
        const results: Record<string, ThemeSearchScore> = {}
        for (const layoutInfo of themes) {
            const theme = layoutInfo.id
            if (theme === "personal") {
                continue
            }
            if (Utils.simplifyStringForSearch(theme) === query) {
                results[theme] = {
                    theme: layoutInfo,
                    lowest: -1,
                    other: 0,
                }
                continue
            }
            const perLayer = Utils.asRecord(layoutInfo.layers ?? [], (layer) => layerScores[layer])
            const language = Locale.language.data

            const keywords = Utils.NoNullInplace([
                layoutInfo.shortDescription,
                layoutInfo.title,
            ]).map((item) => (typeof item === "string" ? item : item[language] ?? item["*"]))

            const other = Math.min(
                SearchUtils.scoreKeywords(query, keywords),
                SearchUtils.scoreKeywords(query, layoutInfo.keywords)
            )
            const lowest = Math.min(other, ...Object.values(perLayer))
            results[theme] = {
                theme: layoutInfo,
                perLayer,
                other,
                lowest,
            }
        }
        return results
    }

    public static sortedByLowestScores(
        search: string,
        themes: MinimalThemeInformation[],
        ignoreLayers: string[] = []
    ): ThemeSearchScore[] {
        const scored = Object.values(this.scoreThemes(search, themes, ignoreLayers))
        scored.sort((a, b) => a.lowest - b.lowest)
        return scored
    }

    public static sortedByLowest(
        search: string,
        themes: MinimalThemeInformation[],
        ignoreLayers: string[] = []
    ): MinimalThemeInformation[] {
        return this.sortedByLowestScores(search, themes, ignoreLayers).map((th) => th.theme)
    }
}