import { resolve } from "path";
import { Observable, of, Subject } from "rxjs";
import { BaseMessage } from "../dependencies/fisappmessagejsutilty/dependencies/dependencies";
import { LoggingService } from "../dependencies/fisloggingservice/services/logging-service";
import { MessageLog } from "../dependencies/fisloggingservice/type/datatype";
import { MessageSynchronisationServiceInterface, MessageSynchronisationServiceSetting } from "../type/datatype";

export class MessageSyncrhonizationService implements MessageSynchronisationServiceInterface {

    settings: MessageSynchronisationServiceSetting
    sourceSrc: LoggingService = new LoggingService()
    targetSrc: LoggingService = new LoggingService()

    public async init(settings: MessageSynchronisationServiceSetting): Promise<void> {
        this.settings = settings;
        // Wrap promise so that init must be instantiated with resolve before proceeding with subscribe method
        let promiseInit: Promise<void> = new Promise((resolve, reject) => {
            try {
                this.sourceSrc.init(settings.incomingSource).then((data) => {
                    if (!data) reject()
                }).then(() => {
                    this.targetSrc.init(settings.target).then((data) => {
                        if (!data) reject()
                        resolve()
                    })
                })
            }
            catch (e) {
                console.error(e)
            }
        })
        return promiseInit
    }

    // Incoming obstriger serves as a trigger point to perform another synchronization
    public subscribe(obsTrigger: Observable<string>): Observable<any> {
        let subjectOutput = this.syncrhonize()
        this.targetSrc.subscribe(subjectOutput)
        subjectOutput.subscribe({
            next: missingMsg => console.log(`Synchronizing ${missingMsg.appData.msgId}`)
        })
        
        // obs.subscribe({
        //     next: element => {
        //         subjectOutput = this.syncrhonize()
        //     }
        // })

        return subjectOutput.asObservable()
    }

    private syncrhonize(): Subject<any> {
        let subjectOutput = new Subject()
        this.acquireData().then((data: { arr1: MessageLog[], arr2: MessageLog[] }) => {
            if (data.arr1.length === data.arr2.length) {
                console.log(`No synchronization needed`)
            } else {
                this.checkArrayDifferences(data).then((data: MessageLog[]) => {
                    data.forEach(msgElement => {
                        subjectOutput.next(msgElement)
                    })
                })
            }
        }).catch((e) => console.error(e))
        return subjectOutput
    }

    // Acquires the available data from designated storage
    private async acquireData(): Promise<any> {
        const promiseQuery: Promise<any> = new Promise((resolve, reject) => {
            let allSets: {
                arr1: MessageLog[],
                arr2: MessageLog[]
            } = {
                arr1: [],
                arr2: []
            }
            let set1
            let set2
            this.sourceSrc.filter({ msgTag: this.settings.incomingSource.tags[0] }).then((data: MessageLog[]) => {
                set1 = data
            }).then(() => {
                this.targetSrc.filter({ msgTag: this.settings.target.tags[0] }).then((data: MessageLog[]) => {
                    set2 = data
                    allSets.arr1 = set1
                    allSets.arr2 = set2
                    resolve(allSets)
                })
            })
        })
        return promiseQuery
    }
    // compare results and return differences`
    private async checkArrayDifferences(args: { arr1?: any[], arr2?: any[] }): Promise<any[]> {
        return new Promise((resolve, reject) => {
            let missingMsg: MessageLog[] = []
            args.arr1.forEach((msgElement: MessageLog) => {
                if (args.arr2.some(obj => obj.appData.msgId === msgElement.appData.msgId)) {
                    console.log(`Item Found!`)
                } else {
                    console.log(`This ${msgElement.appData.msgId} is not found`)
                    missingMsg.push(msgElement)
                    resolve(missingMsg)
                }
            })
        })
    }


}