import { z } from "zod";
import type { JsonObject } from "../core/json.js";

export const X_ACTIVITY_SOURCE_EVENT_TYPE = "stream.thought.source.x.activity";
export const X_ACTIVITY_SOURCE_SCHEMA_VERSION = 1;
export const X_WEBHOOK_REVISION = "x-activity-v2-webhook-v2";
export const X_PUBLIC_POST_EVENT_TYPES = ["post.create", "post.delete"] as const;
export const X_PRIVATE_ACTIVITY_EVENT_TYPES = ["like.create"] as const;
export const X_ACTIVITY_EVENT_TYPES = [...X_PUBLIC_POST_EVENT_TYPES, ...X_PRIVATE_ACTIVITY_EVENT_TYPES] as const;
export const X_ACTIVITY_DIRECTIONS = ["inbound", "outbound"] as const;
export const X_SOURCE_LANES = ["personal-public", "personal-private", "public-watchlist"] as const;

export const xPublicPostEventTypeSchema = z.enum(X_PUBLIC_POST_EVENT_TYPES);
export const xActivityEventTypeSchema = z.enum(X_ACTIVITY_EVENT_TYPES);
export const xActivityDirectionSchema = z.enum(X_ACTIVITY_DIRECTIONS);
export const xSourceLaneSchema = z.enum(X_SOURCE_LANES);
export const xNumericIdSchema = z.string().regex(/^[0-9]{1,19}$/);
export const xUsernameSchema = z.string().regex(/^[A-Za-z0-9_]{1,50}$/);

const xReferenceSchema = z.object({
  type: z.enum(["replied_to", "quoted", "retweeted"]),
  postId: xNumericIdSchema,
}).strict();

const xPositionedTagSchema = z.object({
  start: z.number().int().nonnegative(),
  end: z.number().int().positive(),
  tag: z.string().min(1).max(200),
}).strict();

const xMentionSchema = z.object({
  start: z.number().int().nonnegative(),
  end: z.number().int().positive(),
  username: z.string().min(1).max(100),
  userId: xNumericIdSchema.optional(),
}).strict();

const xUrlEntitySchema = z.object({
  start: z.number().int().nonnegative(),
  end: z.number().int().positive(),
  url: z.string().min(1).max(2_048),
  expandedUrl: z.string().min(1).max(8_192).optional(),
  displayUrl: z.string().min(1).max(2_048).optional(),
  unwoundUrl: z.string().min(1).max(8_192).optional(),
}).strict();

const xEntitiesSchema = z.object({
  hashtags: z.array(xPositionedTagSchema).max(100).optional(),
  cashtags: z.array(xPositionedTagSchema).max(100).optional(),
  mentions: z.array(xMentionSchema).max(100).optional(),
  urls: z.array(xUrlEntitySchema).max(100).optional(),
}).strict();

const xAttachmentsSchema = z.object({
  mediaKeys: z.array(z.string().min(1).max(200)).max(50).optional(),
  pollIds: z.array(z.string().min(1).max(200)).max(10).optional(),
}).strict();

const xTransportSchema = z.object({
  revision: z.literal(X_WEBHOOK_REVISION),
  signatureVerified: z.literal(true),
  kind: z.literal("x-v2-webhook"),
}).strict();

const xActivityEnvelopeFields = {
  eventUuid: z.string().min(1).max(200),
  matchedUserId: xNumericIdSchema,
  subscriptionTag: z.string().min(1).max(200),
  lane: xSourceLaneSchema,
  transport: xTransportSchema,
};

const xPostCreatePayloadSchema = z.object({
  ...xActivityEnvelopeFields,
  eventType: z.literal("post.create"),
  post: z.object({
    postId: xNumericIdSchema,
    authorId: xNumericIdSchema,
    text: z.string().max(100_000),
    createdAt: z.iso.datetime(),
    conversationId: xNumericIdSchema.optional(),
    inReplyToUserId: xNumericIdSchema.optional(),
    editHistoryPostIds: z.array(xNumericIdSchema).min(1).max(100).optional(),
    referencedPosts: z.array(xReferenceSchema).max(100).optional(),
    language: z.string().min(1).max(32).optional(),
    replySettings: z.string().min(1).max(100).optional(),
    possiblySensitive: z.boolean().optional(),
    entities: xEntitiesSchema.optional(),
    attachments: xAttachmentsSchema.optional(),
  }).strict(),
}).strict();

const xPostDeletePayloadSchema = z.object({
  ...xActivityEnvelopeFields,
  eventType: z.literal("post.delete"),
  post: z.object({
    postId: xNumericIdSchema,
    authorId: xNumericIdSchema,
  }).strict(),
}).strict();

const xLikeCreatePayloadSchema = z.object({
  ...xActivityEnvelopeFields,
  eventType: z.literal("like.create"),
  direction: z.literal("outbound"),
  like: z.object({
    likeId: z.string().min(1).max(200),
    actorId: xNumericIdSchema,
    postId: xNumericIdSchema,
    postAuthorId: xNumericIdSchema,
    likedPostCreatedAt: z.iso.datetime().optional(),
    eventTimestampMs: z.string().regex(/^[0-9]{1,16}$/).optional(),
    eventAt: z.iso.datetime().optional(),
  }).strict(),
}).strict();

export const xActivityPayloadSchema = z.discriminatedUnion("eventType", [
  xPostCreatePayloadSchema,
  xPostDeletePayloadSchema,
  xLikeCreatePayloadSchema,
]) as unknown as z.ZodType<JsonObject>;

export type XActivityEventType = z.infer<typeof xActivityEventTypeSchema>;
export type XActivityDirection = z.infer<typeof xActivityDirectionSchema>;
export type XSourceLane = z.infer<typeof xSourceLaneSchema>;
export type XActivityPayload = z.infer<typeof xPostCreatePayloadSchema>
  | z.infer<typeof xPostDeletePayloadSchema>
  | z.infer<typeof xLikeCreatePayloadSchema>;