import { SchedulingRun } from './scheduling-status';
import { inject, Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, tap } from 'rxjs';
import {
  Coach,
  DanceGroup,
  Dancer,
  DancerRequest,
  GroupRequest,
  ResourceKind,
  School,
  SchoolData,
  SchoolRequest,
  Show,
  ShowRequest,
} from './api-models';

@Injectable({ providedIn: 'root' })
export class SchoolApi {
  private readonly http = inject(HttpClient);
  private readonly base = '/api/dance-schools';
  private readonly revisions = new Map<number, number>();

  schools(): Observable<School[]> {
    return this.http.get<School[]>(this.base).pipe(
      tap((schools) => {
        for (const school of schools) this.revisions.set(school.id, school.revision);
      }),
    );
  }
  schoolData(schoolId: number): Observable<SchoolData> {
    return this.http
      .get<SchoolData>(`${this.base}/${schoolId}/data`)
      .pipe(tap((data) => this.revisions.set(schoolId, data.school.revision)));
  }
  private options(schoolId: number, expected?: number): { headers: Record<string, string> } {
    const revision = expected ?? this.revisions.get(schoolId);
    return { headers: revision === undefined ? {} : { 'X-School-Revision': String(revision) } };
  }
  saveSchool(body: SchoolRequest, id?: number, revision?: number): Observable<School> {
    return id === undefined
      ? this.http.post<School>(this.base, body)
      : this.http.put<School>(`${this.base}/${id}`, body, this.options(id, revision));
  }
  saveDancer(
    schoolId: number,
    body: DancerRequest,
    id?: number,
    revision?: number,
  ): Observable<Dancer> {
    return this.save(`${this.base}/${schoolId}/dancers`, body, schoolId, id, revision);
  }
  saveGroup(
    schoolId: number,
    body: GroupRequest,
    id?: number,
    revision?: number,
  ): Observable<DanceGroup> {
    return this.save(`${this.base}/${schoolId}/dance-groups`, body, schoolId, id, revision);
  }
  saveShow(schoolId: number, body: ShowRequest, id?: number, revision?: number): Observable<Show> {
    return this.save(`${this.base}/${schoolId}/shows`, body, schoolId, id, revision);
  }
  schedule(schoolId: number, showId: number): Observable<SchedulingRun> {
    return this.http.post<SchedulingRun>(
      `${this.base}/${schoolId}/shows/${showId}/schedule`,
      null,
      this.options(schoolId),
    );
  }
  saveAssignments(
    schoolId: number,
    showId: number,
    assignments: number[][],
    revision?: number,
  ): Observable<Show> {
    return this.http.put<Show>(
      `${this.base}/${schoolId}/shows/${showId}/assignments`,
      {
        assignments,
      },
      this.options(schoolId, revision),
    );
  }
  finalize(schoolId: number, showId: number, revision?: number): Observable<Show> {
    return this.http.post<Show>(
      `${this.base}/${schoolId}/shows/${showId}/finalize`,
      null,
      this.options(schoolId, revision),
    );
  }
  linkCoach(schoolId: number, dancerId: number, coachId?: number): Observable<Coach> {
    return this.save<Coach>(`${this.base}/${schoolId}/coaches`, { dancerId }, schoolId, coachId);
  }
  unlinkCoach(schoolId: number, coachId: number): Observable<void> {
    return this.http.delete<void>(
      `${this.base}/${schoolId}/coaches/${coachId}/dancer`,
      this.options(schoolId),
    );
  }
  delete(kind: ResourceKind, schoolId: number, id: number, revision?: number): Observable<void> {
    const collection = { school: '', dancer: '/dancers', group: '/dance-groups', show: '/shows' }[
      kind
    ];
    const url =
      kind === 'school' ? `${this.base}/${id}` : `${this.base}/${schoolId}${collection}/${id}`;
    return this.http.delete<void>(url, this.options(schoolId, revision));
  }
  membership(
    schoolId: number,
    groupId: number,
    dancerId: number,
    add: boolean,
    revision?: number,
  ): Observable<void> {
    const url = `${this.base}/${schoolId}/dance-groups/${groupId}/dancers/${dancerId}`;
    return add
      ? this.http.put<void>(url, null, this.options(schoolId, revision))
      : this.http.delete<void>(url, this.options(schoolId, revision));
  }
  private save<T>(
    url: string,
    body: unknown,
    schoolId: number,
    id?: number,
    revision?: number,
  ): Observable<T> {
    return id === undefined
      ? this.http.post<T>(url, body, this.options(schoolId, revision))
      : this.http.put<T>(`${url}/${id}`, body, this.options(schoolId, revision));
  }
}