mapcomplete/Models/ThemeConfig/FilterConfig.ts

import {Translation} from "../../UI/i18n/Translation";
import {TagsFilter} from "../../Logic/Tags/TagsFilter";
import FilterConfigJson from "./Json/FilterConfigJson";
import Translations from "../../UI/i18n/Translations";
import {TagUtils} from "../../Logic/Tags/TagUtils";
import ValidatedTextField from "../../UI/Input/ValidatedTextField";
import {AndOrTagConfigJson} from "./Json/TagConfigJson";
import {UIEventSource} from "../../Logic/UIEventSource";
import {FilterState} from "../FilteredLayer";
import {QueryParameters} from "../../Logic/Web/QueryParameters";
import {Utils} from "../../Utils";

export default class FilterConfig {
    public readonly id: string
    public readonly options: {
        question: Translation;
        osmTags: TagsFilter | undefined;
        originalTagsSpec: string | AndOrTagConfigJson
        fields: { name: string, type: string }[]
    }[];
    public readonly defaultSelection? : number

    constructor(json: FilterConfigJson, context: string) {
        if (json.options === undefined) {
            throw `A filter without options was given at ${context}`
        }
        if (json.id === undefined) {
            throw `A filter without id was found at ${context}`
        }
        if (json.id.match(/^[a-zA-Z0-9_-]*$/) === null) {
            throw `A filter with invalid id was found at ${context}. Ids should only contain letters, numbers or - _`

        }

        if (json.options.map === undefined) {
            throw `A filter was given where the options aren't a list at ${context}`
        }
        this.id = json.id;
        let defaultSelection : number = undefined
        this.options = json.options.map((option, i) => {
            const ctx = `${context}.options[${i}]`;
            const question = Translations.T(
                option.question,
                `${ctx}.question`
            );
            let osmTags = undefined;
            if ((option.fields?.length ?? 0) == 0 && option.osmTags !== undefined) {
                osmTags = TagUtils.Tag(
                    option.osmTags,
                    `${ctx}.osmTags`
                );
            }
            if (question === undefined) {
                throw `Invalid filter: no question given at ${ctx}`
            }

            const fields: { name: string, type: string }[] = ((option.fields) ?? []).map((f, i) => {
                const type = f.type ?? "string"
                if (!ValidatedTextField.ForType(type) === undefined) {
                      throw `Invalid filter: ${type} is not a valid validated textfield type (at ${ctx}.fields[${i}])\n\tTry one of ${Array.from(ValidatedTextField.AvailableTypes()).join(",")}`
                }
                if (f.name === undefined || f.name === "" || f.name.match(/[a-z0-9_-]+/) == null) {
                    throw `Invalid filter: a variable name should match [a-z0-9_-]+ at ${ctx}.fields[${i}]`
                }
                return {
                    name: f.name,
                    type
                }
            })

            if(option.default){
                if(defaultSelection === undefined){
                    defaultSelection = i;
                }else{
                    throw `Invalid filter: multiple filters are set as default, namely ${i} and ${defaultSelection} at ${context}`
                }
            }

            return {question: question, osmTags: osmTags, fields, originalTagsSpec: option.osmTags};
        });
        
        this.defaultSelection = defaultSelection 

        if (this.options.some(o => o.fields.length > 0) && this.options.length > 1) {
            throw `Invalid filter at ${context}: a filter with textfields should only offer a single option.`
        }

        if (this.options.length > 1 && this.options[0].osmTags !== undefined) {
            throw "Error in " + context + "." + this.id + ": the first option of a multi-filter should always be the 'reset' option and not have any filters"
        }
        
        
    }

    public initState(): UIEventSource<FilterState> {

        function reset(state: FilterState): string {
            if (state === undefined) {
                return ""
            }
            return "" + state.state
        }

        let defaultValue = ""
        if(this.options.length > 1){
            defaultValue = ""+(this.defaultSelection ?? 0)
        }else{
            // Only a single option
            if(this.defaultSelection === 0){
                defaultValue = "true"
            }
        }
        const qp = QueryParameters.GetQueryParameter("filter-" + this.id, defaultValue, "State of filter " + this.id)

        if (this.options.length > 1) {
            // This is a multi-option filter; state should be a number which selects the correct entry
            const possibleStates: FilterState [] = this.options.map((opt, i) => ({
                currentFilter: opt.osmTags,
                state: i
            }))

            // We map the query parameter for this case
            return qp.map(str => {
                const parsed = Number(str)
                if (isNaN(parsed)) {
                    // Nope, not a correct number!
                    return undefined
                }
                return possibleStates[parsed]
            }, [], reset)
        }


        const option = this.options[0]

        if (option.fields.length > 0) {
            return qp.map(str => {
                // There are variables in play!
                // str should encode a json-hash
                try {
                    const props = JSON.parse(str)

                    const origTags = option.originalTagsSpec
                    const rewrittenTags = Utils.WalkJson(origTags,
                        v => {
                            if (typeof v !== "string") {
                                return v
                            }
                            for (const key in props) {
                                v = (<string>v).replace("{" + key + "}", props[key])
                            }
                            return v
                        }
                    )
                    const parsed = TagUtils.Tag(rewrittenTags)
                    return <FilterState>{
                        currentFilter: parsed,
                        state: str
                    }
                } catch (e) {
                    return undefined
                }

            }, [], reset)
        }

        // The last case is pretty boring: it is checked or it isn't
        const filterState: FilterState = {
            currentFilter: option.osmTags,
            state: "true"
        }
        return qp.map(
            str => {
                // Only a single option exists here
                if (str === "true") {
                    return filterState
                }
                return undefined
            }, [],
            reset
        )
    }
}