import { IQueryHandler, Query, QueryHandler } from '@nestjs/cqrs';
import { NotFoundError } from '@task-stream/api/shared/domain';
import { ReleaseStatus, StatusCategory } from '@task-stream/api/tracker/domain';
import { FindIssuesRepository } from '../ports/find-issues.repository';
import { FindProjectsRepository } from '../ports/find-projects.repository';
import { FindReleasesRepository } from '../ports/find-releases.repository';
import { FindSprintsRepository } from '../ports/find-sprints.repository';

import { PROPOSAL_LABEL } from '../proposals';

/** Tickets with this label are offered to newcomers on public pages. */
export const GOOD_FIRST_LABEL = 'good-first-issue';

/**
 * What a public project shows to the world in one call: where it is going
 * (epics with dates, releases), what it is doing (the sprint under way) and
 * where someone new could help. Paths are relative to the web app.
 */
export interface Showcase {
  project: {
    id: string;
    key: string;
    name: string;
    description: string | null;
  };
  activeSprint: {
    name: string;
    goal: string | null;
    startDate: string;
    endDate: string;
    percent: number;
  } | null;
  roadmap: {
    key: string;
    title: string;
    startDate: string | null;
    dueDate: string | null;
    percent: number;
    done: boolean;
    /** How many want it. */
    votes: number;
    path: string;
  }[];
  releases: {
    name: string;
    status: ReleaseStatus;
    targetDate: string | null;
    releasedAt: string | null;
    percent: number;
    notes: string | null;
  }[];
  goodFirst: { key: string; title: string; type: string; path: string }[];
  /** Bug reports and ideas from the public: whether it takes them, where, and the open ones. */
  proposals: {
    open: boolean;
    /** The form in the web app, while it takes them. */
    path: string | null;
    /** Open proposals, most voted first. */
    top: {
      key: string;
      title: string;
      type: string;
      votes: number;
      path: string;
    }[];
  };
}

export class GetShowcaseQuery extends Query<Showcase> {
  constructor(public readonly project: string) {
    super();
  }
}

const FINISHED = [StatusCategory.DONE, StatusCategory.CANCELLED];
const OPEN = [
  StatusCategory.TODO,
  StatusCategory.IN_PROGRESS,
  StatusCategory.QA,
];

@QueryHandler(GetShowcaseQuery)
export class GetShowcaseQueryHandler
  implements IQueryHandler<GetShowcaseQuery, Showcase>
{
  constructor(
    private readonly findProjects: FindProjectsRepository,
    private readonly findIssues: FindIssuesRepository,
    private readonly findReleases: FindReleasesRepository,
    private readonly findSprints: FindSprintsRepository,
  ) {}

  /** Public projects only: anything else is not there. */
  async execute(query: GetShowcaseQuery): Promise<Showcase> {
    const project =
      (await this.findProjects.findById(query.project)) ??
      (await this.findProjects.findByKey(query.project.toUpperCase()));
    if (!project?.isPublic) throw new NotFoundError('Project', query.project);
    const path = (key: string) => `/p/${project.key}/issues/${key}`;
    const [epics, releases, sprint, goodFirst, proposals] = await Promise.all([
      this.findIssues.epics(project.id),
      this.findReleases.findByProject(project.id),
      this.findSprints.findActive(project.id),
      this.findIssues.search({
        projectId: project.id,
        labels: [GOOD_FIRST_LABEL],
        categories: [StatusCategory.TODO],
        limit: 20,
        offset: 0,
      }),
      this.findIssues.search({
        projectId: project.id,
        labels: [PROPOSAL_LABEL],
        categories: OPEN,
        limit: 100,
        offset: 0,
      }),
    ]);
    const visible = releases
      .filter((r) => r.status !== ReleaseStatus.ARCHIVED)
      .sort((a, b) =>
        (b.releasedAt ?? b.targetDate ?? '').localeCompare(
          a.releasedAt ?? a.targetDate ?? '',
        ),
      )
      .slice(0, 6);
    const progress = await Promise.all(
      visible.map((r) => this.findIssues.releaseProgress(r.id)),
    );
    return {
      project: {
        id: project.id,
        key: project.key,
        name: project.name,
        description: project.description,
      },
      activeSprint: sprint
        ? {
            name: sprint.name,
            goal: sprint.goal,
            startDate: sprint.startDate,
            endDate: sprint.endDate,
            percent: (await this.findIssues.sprintProgress(sprint.id)).percent,
          }
        : null,
      roadmap: epics.map(({ issue, progress: p }) => ({
        key: issue.key,
        title: issue.title,
        startDate: issue.startDate,
        dueDate: issue.dueDate,
        percent: p.percent,
        done: FINISHED.includes(issue.statusCategory),
        votes: issue.votes,
        path: path(issue.key),
      })),
      releases: visible.map((r, i) => ({
        name: r.name,
        status: r.status,
        targetDate: r.targetDate,
        releasedAt: r.releasedAt,
        percent: progress[i].percent,
        notes: r.status === ReleaseStatus.RELEASED ? r.notes : null,
      })),
      goodFirst: goodFirst.items.map((i) => ({
        key: i.key,
        title: i.title,
        type: i.type,
        path: path(i.key),
      })),
      proposals: {
        open: project.acceptsProposals,
        path: project.acceptsProposals ? `/p/${project.key}/propose` : null,
        top: [...proposals.items]
          .sort((a, b) => b.votes - a.votes)
          .slice(0, 10)
          .map((i) => ({
            key: i.key,
            title: i.title,
            type: i.type,
            votes: i.votes,
            path: path(i.key),
          })),
      },
    };
  }
}