import { Injectable, NgZone } from '@angular/core';
import { ConfigService } from './config.service';
import { Observable, ReplaySubject, Subject, Subscribable, Subscription, from, map, tap, timer } from 'rxjs';
import { Plan } from '../_models/plan';
import { MatDialog } from '@angular/material/dialog';
import { Resume, ResumeDialog } from '../plan-display/resume-dialog.component';
import { v4 as uuidv4 } from 'uuid';
import { invoke } from '@tauri-apps/api';
import { appWindow } from '@tauri-apps/api/window';


export enum EntryType {
  PlanForceNext = "PlanForceNext",
  PlanForcePrev = "PlanForcePrev",
  ZoneEnter = "ZoneEnter",
  CheckpointReached = "CheckpointReached",
}

export interface TrackEntry {
  type: EntryType;
  zone: string;
  current_elapsed_millis: number;
}

export interface RunHistoryMetadata {
  uuid: string;
  currentElapsedMillis: number;
  associatedName: string;
  last_updated: number;
}

interface RunHistoryInterface {
  uuid: string;
  current_elapsed_millis: number;
  associated_name: string;
  last_updated: number;

  entries: TrackEntry[];
}

export class RunHistory {

  uuid: string;
  currentElapsedMillis: number;
  entries: TrackEntry[];
  associatedName: string;
  last_updated: number;

  plan?: Plan;

  constructor(data: RunHistoryInterface) {
    this.uuid = data.uuid;
    this.currentElapsedMillis = data.current_elapsed_millis;
    this.entries = data.entries;
    this.last_updated = data.last_updated;
    this.associatedName = data.associated_name;
  }

  toInterface(): RunHistoryInterface {
    return {
      uuid: this.uuid,
      current_elapsed_millis: this.currentElapsedMillis,
      last_updated: this.last_updated,
      entries: this.entries,
      associated_name: this.associatedName,
    }
  }
}

@Injectable({
  providedIn: 'root'
})
export class TimeTrackerService {

  private currentRunHistory?: RunHistory;

  private timerSubscription?: Subscription;
  private debouncedSaveStopwatch?: Subscription;
  resumeOnNext: boolean = false;

  private start?: Date;
  private latest?: Date;

  private newRun: Subject<void> = new Subject<void>();

  private active: boolean = false;

  private storedHistoriesSubject: Subject<Map<string, RunHistoryMetadata>> = new ReplaySubject<Map<string, RunHistoryMetadata>>(1);

  private pushSubject: Subject<TrackEntry> = new ReplaySubject<TrackEntry>(1);
  private newCurrentRunHistorySubject: Subject<RunHistory> = new ReplaySubject<RunHistory>(1);

  constructor(private configService: ConfigService, public dialog: MatDialog, private zone: NgZone) {
    this.loadCache();
    appWindow.listen("entered", (entered) => {
      if (entered.payload && typeof entered.payload === 'string')
        this.onZoneEnter(entered.payload);
    });

    this.pushSubject.subscribe((entry) => {
      this.currentRunHistory?.entries.push(entry);
    });
  }

  public getCurrentRunHistory(): Observable<RunHistory> {
    return this.newCurrentRunHistorySubject.asObservable();
  }

  getLatestEntry() {
    return this.pushSubject.asObservable();
  }

  private setCurrentRunHistory(history: RunHistory) {
    this.currentRunHistory = history;
    this.newCurrentRunHistorySubject.next(history);
  }

  get elapsedTimeMillis() {
    this.latest = new Date();
    return this.latest!.valueOf() - this.start!.valueOf();
  }

  get isActive() {
    return this.active;
  }

  get hasRunLoaded() {
    return !!this.currentRunHistory;
  }

  public get storedHistories(): Observable<Map<string, RunHistoryMetadata>> {
    return this.storedHistoriesSubject;
  }
  public getNewRunSubject(): Observable<void>{
    return this.newRun.asObservable();
  }
  onNewRun(plan: Plan) {
    if (this.timerSubscription && !this.timerSubscription.closed) this.timerSubscription.unsubscribe();
    if (this.debouncedSaveStopwatch && !this.debouncedSaveStopwatch.closed) this.debouncedSaveStopwatch.unsubscribe();

    this.start = undefined;
    this.latest = undefined;
    this.active = false;

    if (plan.last_stored_time) {
      this.loadHistory(plan.last_stored_time).subscribe(history => {

        if (history) {
          this.setCurrentRunHistory(history);
        } else {
          //Legacy or missing history, attempt to preserve elapsed time
          this.setCurrentRunHistory(this.createNew(plan.name));
          plan.last_stored_time = this.currentRunHistory!.uuid;
          const old_time = parseInt(plan.last_stored_time, 10);
          if (!isNaN(old_time) && old_time > 0) {
            this.currentRunHistory!.currentElapsedMillis = old_time;
          }
          plan.requestSelfSave();
        }

        this.currentRunHistory!.plan = plan;
        this.askResume(plan);
      });
    } else {
      this.setCurrentRunHistory(this.createNew(plan.name));
      this.currentRunHistory!.plan = plan;
      this.resumeOnNext = true;
    }
  }

  ///Assumes currentPlan is set...
  private startStopwatch() {
    this.stop(); // Make sure we stop before starting again

    if (this.currentRunHistory?.currentElapsedMillis) {
      this.start = new Date(Date.now() - this.currentRunHistory.currentElapsedMillis);
    } else {
      this.start = new Date();
    }

    this.latest = new Date();
    this.active = true;

    //Make sure this is always cleared if e.g. force started! should be fine but just in case!!
    this.resumeOnNext = false;



    this.timerSubscription = timer(0, 1000).subscribe(() => {
      this.zone.run(() => {
        this.latest = new Date();
        this.currentRunHistory!.currentElapsedMillis = this.elapsedTimeMillis;
      });
    });

    this.debouncedSaveStopwatch = timer(0, 5000).subscribe(() => {
      this.underlyingSaveStopwatch();
    })
  }

  private underlyingSaveStopwatch() {
    if (this.currentRunHistory && this.active && this.start && this.latest) {
      this.currentRunHistory!.currentElapsedMillis = this.elapsedTimeMillis;
      this.currentRunHistory!.last_updated = Date.now();

      this.saveHistory(this.currentRunHistory!).subscribe(() => { });
      this.loadCache();


      if (this.currentRunHistory.plan) {
        this.currentRunHistory.plan.last_stored_time = this.currentRunHistory.uuid;
        this.currentRunHistory.plan.requestSelfSave();
      }
    }
  }

  public saveHistory(currentRunHistory: RunHistory) {
    return from(invoke('save_history', { currentRunHistory: currentRunHistory.toInterface() })).pipe(tap(() => this.loadCache()));
  }

  public loadHistory(uuid: string) {
    return from(invoke<RunHistoryInterface>('load_history_at_uuid', { uuid: uuid })).pipe(map(history => {
      if (history) {
        return new RunHistory(history);
      }
      return undefined;
    }));
  }

  public onForceNext(forced_area: string) {
    if (this.configService.config.enableStopwatch) {
      if (this.isActive) {
        this.pushSubject.next({
          type: EntryType.PlanForceNext,
          zone: forced_area,
          current_elapsed_millis: this.elapsedTimeMillis
        });
      }
    }
  }

  public onForcePrev(forced_area: string) {
    if (this.configService.config.enableStopwatch) {
      if (this.isActive) {
        this.pushSubject.next({
          type: EntryType.PlanForcePrev,
          zone: forced_area,
          current_elapsed_millis: this.elapsedTimeMillis
        });
      }
    }
  }

  //Not perfect but good enough..
  public reportCheckpoint(checkpoint: string) {
    this.pushSubject.next({
      type: EntryType.CheckpointReached,
      zone: checkpoint,
      current_elapsed_millis: this.elapsedTimeMillis
    })
  }

  public stop() {
    if (this.timerSubscription && !this.timerSubscription.closed) this.timerSubscription.unsubscribe();
    if (this.debouncedSaveStopwatch && !this.debouncedSaveStopwatch.closed) this.debouncedSaveStopwatch.unsubscribe();

    //Do a nice little save here as well!
    this.underlyingSaveStopwatch();

    this.start = undefined;
    this.latest = undefined;
    this.active = false;
  }

  public startLoaded() {
    if (this.currentRunHistory) {
      this.startStopwatch();
    }
  }

  public hmsTimestamp(elapsed?: number): string {
    return hmsTimestamp(elapsed);
  }

  public loadCache() {
    from(invoke<Map<string, RunHistoryMetadata>>('load_cache')).subscribe(data => {
      this.zone.run(() => {
        const cache = new Map<string, RunHistoryMetadata>();
        Object.values(data).forEach((value) => {
          cache.set(value.uuid, {
            uuid: value.uuid,
            currentElapsedMillis: value.current_elapsed_millis,
            associatedName: value.associated_name,
            last_updated: value.last_updated,
          });
        });
        console.log("sending new cache!");
        this.storedHistoriesSubject.next(cache);
      });
    });
  }

  private onZoneEnter(zone: string) {
    if (!this.currentRunHistory) return;

    if (this.configService.config.enableStopwatch) {
      if(!this.isActive && this.resumeOnNext) {
        this.resumeOnNext = false;
        this.startStopwatch();
      }

      if(!this.isActive && !this.resumeOnNext) {
        //Don't start timer if not meant to auto resumes on next.
        return;
      }

      this.pushSubject.next({
        type: EntryType.ZoneEnter,
        zone: zone,
        current_elapsed_millis: this.elapsedTimeMillis
      });
    }
  }


  private askResume(plan: Plan) {
    const dialogRef = this.dialog.open(ResumeDialog, { disableClose: true });

    dialogRef.afterClosed().subscribe(resume => {
      switch (resume) {
        case Resume.Instant:
          this.startStopwatch();
          this.loadReachedCheckpoints();
          break;
        case Resume.Next:
          this.resumeOnNext = true;
          this.loadReachedCheckpoints();
          break;
        case Resume.Discard:
          this.setCurrentRunHistory(this.createNew(plan.name));
          this.loadReachedCheckpoints();
          plan.last_stored_time = this.currentRunHistory!.uuid;
          this.resumeOnNext = true;
          plan.requestSelfSave();
          break;
        case Resume.NewRun:
          this.setCurrentRunHistory(this.createNew(plan.name));
          this.loadReachedCheckpoints();
          plan.last_stored_time = this.currentRunHistory!.uuid;
          this.resumeOnNext = true;
          plan.requestSelfSave();
          this.newRun.next();
          break;
      }
    })
  }

  
  loadReachedCheckpoints() {
    if (!this.currentRunHistory || !this.currentRunHistory.plan || !this.configService.config.runCompareHistory) return;

    this.loadHistory(this.configService.config.runCompareHistory).subscribe(history => {
      if (!history) return;
      const checkpoints = new Map(history.entries.filter(entry => entry.type === EntryType.CheckpointReached).map(entry => [entry.zone, entry.current_elapsed_millis]));
      const ourCheckpointValidZones = new Map(this.currentRunHistory?.plan?.plan.filter(entry => checkpoints.has(entry.uuid!)).map(entry => [entry.uuid!, entry]));
      this.currentRunHistory?.entries.filter(entry => entry.type === EntryType.CheckpointReached).forEach(entry => {
        if (ourCheckpointValidZones.has(entry.zone)) {
          ourCheckpointValidZones.get(entry.zone)!.checkpoint_your_millis = entry.current_elapsed_millis;
        }
      })
    });
  }

  private createNew(associatedName?: string) {
    const uuid = uuidv4();

    return new RunHistory({
      uuid,
      associated_name: associatedName || 'Unnamed',
      current_elapsed_millis: 0,
      last_updated: Date.now(),
      entries: [],
    });
  }
}

export function hmsTimestamp(elapsed?: number): string {
  if (elapsed == null || elapsed == undefined) return "N/A";

  const h = String(Math.floor(elapsed / 3600000)).padStart(2, '0');
  const m = String(Math.floor((elapsed % 3600000) / 60000)).padStart(2, '0');
  const s = String(Math.floor((elapsed % 60000) / 1000)).padStart(2, '0');

  return `${h}:${m}:${s}`;
}