import {
  ActivityReadModel,
  CommentReadModel,
  IssueLinkReadModel,
  IssueReadModel,
  IssueTimelineEntry,
  ProjectReadModel,
  ReleaseReadModel,
} from '@task-stream/api/tracker/domain';
import { Schema } from 'mongoose';

/* Read model (MongoDB): denormalised documents shaped for the GraphQL queries. */

type Doc<T extends { id: string }> = Omit<T, 'id'> & { _id: string };

export type ProjectDoc = Doc<ProjectReadModel> & { memberIds: string[] };
/** Links are split: outward ones come from the issue itself, inward ones from other issues' events. */
export type IssueDoc = Doc<Omit<IssueReadModel, 'links'>> & {
  outwardLinks: IssueLinkReadModel[];
  inwardLinks: IssueLinkReadModel[];
};
export type CommentDoc = Doc<CommentReadModel>;
export type ReleaseDoc = Doc<ReleaseReadModel>;
export type ActivityDoc = Doc<ActivityReadModel>;
export type TimelineDoc = Doc<IssueTimelineEntry>;

export const ReadModels = {
  Project: 'ProjectReadModel',
  Issue: 'IssueReadModel',
  Comment: 'CommentReadModel',
  Release: 'ReleaseReadModel',
  Activity: 'ActivityReadModel',
  Timeline: 'IssueTimelineReadModel',
} as const;

const userRef = { _id: false, id: String, name: String };
// `type` must be wrapped: a bare `type` key would declare the whole subdocument a String.
const link = {
  _id: false,
  type: { type: String },
  direction: String,
  issueId: String,
  issueKey: String,
};
const loose = { strict: false, versionKey: false, _id: false } as const;

export const ProjectSchema = new Schema<ProjectDoc>(
  {
    _id: String,
    key: { type: String, unique: true },
    isPublic: { type: Boolean, index: true },
    memberIds: { type: [String], index: true },
    owner: userRef,
    members: [{ _id: false, user: userRef, role: String }],
    version: Number,
  },
  { ...loose, collection: 'projects_view' },
);

export const IssueSchema = new Schema<IssueDoc>(
  {
    _id: String,
    projectId: { type: String, index: true },
    key: { type: String, unique: true },
    status: String,
    statusCategory: String,
    reporter: userRef,
    assignee: userRef,
    release: { _id: false, id: String, name: String },
    outwardLinks: [link],
    inwardLinks: [link],
    attachments: [
      {
        _id: false,
        id: String,
        fileName: String,
        mimeType: String,
        size: Number,
        uploadedBy: userRef,
        uploadedAt: String,
        commentId: String,
      },
    ],
    labels: [String],
    version: Number,
  },
  { ...loose, collection: 'issues_view' },
);
IssueSchema.index({ projectId: 1, status: 1, updatedAt: -1 });
IssueSchema.index({ projectId: 1, statusCategory: 1 });
IssueSchema.index({ 'assignee.id': 1 });
IssueSchema.index({ 'release.id': 1 });
IssueSchema.index({ title: 'text', description: 'text', key: 'text' });

export const CommentSchema = new Schema<CommentDoc>(
  {
    _id: String,
    issueId: { type: String, index: true },
    author: userRef,
    version: Number,
  },
  { ...loose, collection: 'comments_view' },
);
CommentSchema.index({ issueId: 1, createdAt: 1 });

export const ReleaseSchema = new Schema<ReleaseDoc>(
  { _id: String, projectId: { type: String, index: true }, version: Number },
  { ...loose, collection: 'releases_view' },
);

export const ActivitySchema = new Schema<ActivityDoc>(
  {
    _id: String,
    projectId: String,
    issueId: String,
    actor: userRef,
  },
  { ...loose, collection: 'activity' },
);
ActivitySchema.index({ projectId: 1, occurredAt: -1 });
ActivitySchema.index({ issueId: 1, occurredAt: -1 });

/** Every status and release step of every ticket (statistics). */
export const TimelineSchema = new Schema<TimelineDoc>(
  { _id: String, projectId: String, issueId: String, at: String },
  { ...loose, collection: 'issue_timeline' },
);
TimelineSchema.index({ projectId: 1, at: 1 });

export const READ_MODEL_SCHEMAS = [
  { name: ReadModels.Project, schema: ProjectSchema },
  { name: ReadModels.Issue, schema: IssueSchema },
  { name: ReadModels.Comment, schema: CommentSchema },
  { name: ReadModels.Release, schema: ReleaseSchema },
  { name: ReadModels.Activity, schema: ActivitySchema },
  { name: ReadModels.Timeline, schema: TimelineSchema },
];

export function fromDoc<T extends { _id: string }>(
  doc: T,
): Omit<T, '_id'> & { id: string } {
  const { _id, ...rest } = doc;
  return { id: _id, ...rest };
}

export function issueFromDoc(doc: IssueDoc): IssueReadModel {
  const { _id, outwardLinks, inwardLinks, ...rest } = doc;
  return {
    id: _id,
    ...rest,
    links: [...(outwardLinks ?? []), ...(inwardLinks ?? [])],
    // Tickets projected before attachments existed have none.
    attachments: rest.attachments ?? [],
  };
}