import { inject, Injectable, Provider } from '@angular/core';
import { injectDispatch } from '@ngrx/signals/events';
import {
  Attachment,
  AttachmentsGateway,
  IssueLink,
  IssuesGateway,
  IssueLinkType,
  UpdateIssueInput,
} from '@task-stream/web/tracker/domain';
import { map, Observable } from 'rxjs';
import { issuePageEvents } from '../events/issue.events';
import { IssueStore } from '../stores/issue.store';

/**
 * One ticket for presenters: details, comments and history, live. Commands act
 * on the open ticket, so pages don't pass its id.
 */
@Injectable()
export class IssueFacade {
  private readonly store = inject(IssueStore);
  private readonly dispatch = injectDispatch(issuePageEvents);
  private readonly files = inject(AttachmentsGateway);
  private readonly issues = inject(IssuesGateway);

  readonly issue = this.store.issue;
  readonly comments = this.store.comments;
  readonly history = this.store.history;
  readonly outwardLinks = this.store.outwardLinks;
  readonly inwardLinks = this.store.inwardLinks;
  /** Tickets hanging from the open one, and how far they have got. */
  readonly children = this.store.children;
  readonly childProgress = this.store.childProgress;
  /** Ticked steps of the open ticket's checklist. */
  readonly checklistProgress = this.store.checklistProgress;
  readonly loading = this.store.loading;
  readonly error = this.store.error;
  /** Signed-in user's id (authors can edit their comments). */
  readonly me = this.store.me;
  /** Whether the signed-in person follows the open ticket. */
  readonly watching = this.store.watching;

  /** Loads the ticket (by id or key, e.g. BE-3) and follows its changes. */
  open(idOrKey: string): void {
    this.dispatch.opened({ idOrKey });
  }

  /** QA_FAILED and CANCELLED need a reason. */
  changeStatus(status: string, reason?: string | null): void {
    this.withIssue((issueId) =>
      this.dispatch.statusChangeRequested({ issueId, status, reason }),
    );
  }

  assign(assigneeId: string | null): void {
    this.withIssue((issueId) =>
      this.dispatch.assignRequested({ issueId, assigneeId }),
    );
  }

  update(changes: Omit<UpdateIssueInput, 'issueId'>): void {
    this.withIssue((issueId) =>
      this.dispatch.updateRequested({ issueId, ...changes }),
    );
  }

  /** Relates this ticket with another one by its key (e.g. BE-3). */
  link(type: IssueLinkType, targetKey: string): void {
    this.withIssue((issueId) =>
      this.dispatch.linkByKeyRequested({ issueId, type, targetKey }),
    );
  }

  unlink(link: IssueLink): void {
    this.withIssue((issueId) =>
      this.dispatch.unlinkRequested({
        issueId,
        type: link.type,
        targetIssueId: link.issueId,
      }),
    );
  }

  /** null: back to the backlog. */
  setSprint(sprintId: string | null): void {
    this.withIssue((issueId) =>
      this.dispatch.sprintChangeRequested({ issueId, sprintId }),
    );
  }

  setRelease(releaseId: string | null): void {
    this.withIssue((issueId) =>
      this.dispatch.releaseChangeRequested({ issueId, releaseId }),
    );
  }

  /** `files` are attached under the new comment; `replyTo` answers one. */
  addComment(
    body: string,
    files: File[] = [],
    replyTo: string | null = null,
  ): void {
    this.withIssue((issueId) =>
      this.dispatch.commentAddRequested({ issueId, body, files, replyTo }),
    );
  }

  /** To the trash (true) or back from it (false). */
  setTrashed(trashed: boolean): void {
    this.withIssue((issueId) =>
      this.dispatch.trashRequested({ issueId, trashed }),
    );
  }

  /** Follow the ticket (or stop): be told when it moves or gets a comment. */
  setWatching(watching: boolean): void {
    this.withIssue((issueId) =>
      this.dispatch.watchRequested({ issueId, watching }),
    );
  }

  /** Places the open ticket under another one by its key; null: back to the top. */
  setParent(parentKey: string | null): void {
    this.withIssue((issueId) =>
      this.dispatch.parentRequested({ issueId, parentKey }),
    );
  }

  /** Creates a ticket under the open one. */
  addSubtask(title: string, type: string): void {
    const issue = this.store.issue();
    if (!issue || !title.trim()) return;
    this.dispatch.subtaskCreateRequested({
      projectId: issue.projectId,
      parentId: issue.id,
      type,
      title: title.trim(),
    });
  }

  addChecklistItem(text: string): void {
    if (!text.trim()) return;
    this.withIssue((issueId) =>
      this.dispatch.checklistAddRequested({ issueId, text: text.trim() }),
    );
  }

  updateChecklistItem(
    itemId: string,
    changes: { text?: string; done?: boolean },
  ): void {
    this.withIssue((issueId) =>
      this.dispatch.checklistUpdateRequested({ issueId, itemId, changes }),
    );
  }

  removeChecklistItem(itemId: string): void {
    this.withIssue((issueId) =>
      this.dispatch.checklistRemoveRequested({ issueId, itemId }),
    );
  }

  /** Attaches files to the ticket (or under one of its comments). */
  attach(files: File[], commentId: string | null = null): void {
    if (!files.length) return;
    this.withIssue((issueId) =>
      this.dispatch.attachRequested({ issueId, files, commentId }),
    );
  }

  removeAttachment(attachmentId: string): void {
    this.withIssue((issueId) =>
      this.dispatch.attachmentRemoveRequested({ issueId, attachmentId }),
    );
  }

  /** The file's bytes, to show an image or save the file. */
  fileOf(attachment: Attachment): Observable<Blob> {
    const issueId = this.store.issue()?.id ?? '';
    return this.files.download(issueId, attachment);
  }

  /** A file's bytes by id alone (an image inside a description or comment). */
  fileById(attachmentId: string): Observable<Blob> {
    return this.fileOf({ id: attachmentId } as Attachment);
  }

  /**
   * Uploads an image pasted into a text and answers its id, to write
   * `![name](attachment:<id>)`. It also shows among the ticket's files.
   */
  uploadImage(file: File): Observable<string> {
    const issueId = this.store.issue()?.id ?? '';
    return this.files.upload(issueId, file).pipe(
      map((uploaded) => {
        this.dispatch.imagePasted({ issueId });
        return uploaded.attachmentId;
      }),
    );
  }

  /** Votes for the open ticket (`on`) or takes the vote back. */
  vote(on: boolean): void {
    this.withIssue((issueId) => this.dispatch.voteRequested({ issueId, on }));
  }

  /** Adds (`on`) or takes back the signed-in person's reaction. */
  react(commentId: string, emoji: string, on: boolean): void {
    this.dispatch.reactRequested({ commentId, emoji, on });
  }

  /** A copy of what the open ticket says; answers its key. */
  duplicate(): Observable<string | null> {
    const issueId = this.store.issue()?.id ?? '';
    return this.issues
      .duplicate(issueId)
      .pipe(map((result) => result.key ?? null));
  }

  editComment(commentId: string, body: string): void {
    this.dispatch.commentEditRequested({ commentId, body });
  }

  deleteComment(commentId: string): void {
    this.dispatch.commentDeleteRequested({ commentId });
  }

  private withIssue(command: (issueId: string) => void): void {
    const issueId = this.store.issue()?.id;
    if (issueId) command(issueId);
  }
}

/** Store + facade of a ticket, for the issue route's component. */
export function provideIssueFacade(): Provider[] {
  return [IssueStore, IssueFacade];
}