// Copyright 2022 - 2024 Gnuxie <Gnuxie@protonmail.com>
// Copyright 2021 The Matrix.org Foundation C.I.C.
//
// SPDX-License-Identifier: AFL-3.0 AND Apache-2.0
//
// SPDX-FileAttributionText: <text>
// This modified file incorporates work from mjolnir
// https://github.com/matrix-org/mjolnir
// </text>

import { MatrixClient } from "matrix-bot-sdk";
import { strict as assert } from "assert";
import * as crypto from "crypto";
import {
  MatrixEmitter,
  MatrixSendClient,
} from "matrix-protection-suite-for-matrix-bot-sdk";
import {
  NoticeMessageContent,
  ReactionEvent,
  RoomEvent,
  TextMessageContent,
  Value,
  StringEventIDSchema,
} from "matrix-protection-suite";
import { Type } from "@sinclair/typebox";
import { Draupnir } from "../../../src/Draupnir";
import {
  StringEventID,
  StringRoomID,
} from "@the-draupnir-project/matrix-basic-types";

export const ReplyContent = Type.Intersect([
  Type.Object({
    "m.relates_to": Type.Object({
      "m.in_reply_to": Type.Object({
        event_id: StringEventIDSchema,
      }),
    }),
  }),
  Type.Union([NoticeMessageContent, TextMessageContent]),
]);
export type ReplyContent = typeof ReplyContent;

/**
 * Returns a promise that resolves to the first event replying to the event produced by targetEventThunk.
 * @param matrix A MatrixEmitter from a MatrixClient that is already in the targetRoom. We will use it to listen for the event produced by targetEventThunk.
 * This function assumes that the start() has already been called on the client.
 * @param targetRoom The room to listen for the reply in.
 * @param targetEventThunk A function that produces an event ID when called. This event ID is then used to listen for a reply.
 * @returns The replying event.
 */
export async function getFirstReply(
  matrix: MatrixEmitter,
  targetRoom: string,
  targetEventThunk: () => Promise<string>
): Promise<RoomEvent<ReplyContent>> {
  return getNthReply(matrix, targetRoom, 1, targetEventThunk);
}

/**
 * Returns a promise that resolves to the nth event replying to the event produced by targetEventThunk.
 * @param matrix A MatrixEmitter from a MatrixClient that is already in the targetRoom. We will use it to listen for the event produced by targetEventThunk.
 * This function assumes that the start() has already been called on the client.
 * @param targetRoom The room to listen for the reply in.
 * @param n The number of events to wait for. Must be >= 1.
 * @param targetEventThunk A function that produces an event ID when called. This event ID is then used to listen for a reply.
 * @returns The replying event.
 */
export async function getNthReply(
  matrix: MatrixEmitter,
  targetRoom: string,
  n: number,
  targetEventThunk: () => Promise<string>
): Promise<RoomEvent<ReplyContent>> {
  if (Number.isNaN(n) || !Number.isInteger(n) || n <= 0) {
    throw new TypeError(`Invalid number of events ${n}`);
  }
  const reactionEvents: RoomEvent[] = [];
  const addEvent = function (roomId: string, event: RoomEvent) {
    if (roomId !== targetRoom) return;
    if (event.type !== "m.room.message") return;
    reactionEvents.push(event);
  };
  let targetCb;
  try {
    matrix.on("room.event", addEvent);
    const targetEventId = await targetEventThunk();
    if (typeof targetEventId !== "string") {
      throw new TypeError();
    }
    for (const event of reactionEvents) {
      if (Value.Check(ReplyContent, event.content)) {
        const in_reply_to = event.content["m.relates_to"]["m.in_reply_to"];
        if (in_reply_to.event_id === targetEventId) {
          n -= 1;
          if (n === 0) {
            return event as RoomEvent<ReplyContent>;
          }
        }
      }
    }
    return await new Promise((resolve) => {
      targetCb = function (roomId: string, event: RoomEvent) {
        if (roomId !== targetRoom) return;
        if (event.type !== "m.room.message") return;
        if (Value.Check(ReplyContent, event.content)) {
          const in_reply_to = event.content["m.relates_to"]["m.in_reply_to"];
          if (in_reply_to.event_id === targetEventId) {
            n -= 1;
            if (n === 0) {
              resolve(event as RoomEvent<ReplyContent>);
            }
          }
        }
      };
      matrix.on("room.event", targetCb);
    });
  } finally {
    matrix.removeListener("room.event", addEvent);
    // the type feedback for eslitn has to be wrong here i don't get it.
    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
    if (targetCb) {
      matrix.removeListener("room.event", targetCb);
    }
  }
}

/**
 * Returns a promise that resolves to an event that is reacting to the event produced by targetEventThunk.
 * @param matrix A MatrixEmitter for a MatrixClient that is already in the targetRoom that can be started to listen for the event produced by targetEventThunk.
 * This function assumes that the start() has already been called on the client.
 * @param targetRoom The room to listen for the reaction in.
 * @param reactionKey The reaction key to wait for.
 * @param targetEventThunk A function that produces an event ID when called. This event ID is then used to listen for a reaction.
 * @returns The reaction event.
 */
export async function getFirstReaction(
  matrix: MatrixEmitter,
  targetRoom: string,
  reactionKey: string,
  targetEventThunk: () => Promise<string>
): Promise<ReactionEvent> {
  const reactionEvents: ReactionEvent[] = [];
  const addEvent = function (roomId: string, event: RoomEvent) {
    if (roomId !== targetRoom) return;
    if (!Value.Check(ReactionEvent, event)) return;
    reactionEvents.push(event);
  };
  let targetCb;
  try {
    matrix.on("room.event", addEvent);
    const targetEventId = await targetEventThunk();
    for (const event of reactionEvents) {
      const relates_to = event.content?.["m.relates_to"];
      if (
        relates_to?.event_id === targetEventId &&
        relates_to.key === reactionKey
      ) {
        return event;
      }
    }
    return await new Promise((resolve) => {
      targetCb = function (roomId: string, event: RoomEvent) {
        if (roomId !== targetRoom) return;
        if (!Value.Check(ReactionEvent, event)) return;
        const relates_to = event.content["m.relates_to"];
        if (
          relates_to?.event_id === targetEventId &&
          relates_to.key === reactionKey
        ) {
          resolve(event);
        }
      };
      matrix.on("room.event", targetCb);
    });
  } finally {
    matrix.off("room.event", addEvent);
    // idk why the type checker can't detect that this condition is necessary.
    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
    if (targetCb) {
      matrix.off("room.event", targetCb);
    }
  }
}

/**
 * Get and wait for the first event that matches a predicate.
 * @param details.lookAfterEvent A function that returns an event id to look for
 * in the sync timeline before matching. Or a function that returns undefined if
 * `getFirstEventMatching` should start matching events right away.
 * @returns The event matching the predicate provided.
 */
export async function getFirstEventMatching(details: {
  matrix: MatrixEmitter;
  targetRoom: string;
  lookAfterEvent: () => Promise</*event id*/ string | undefined>;
  predicate: (event: RoomEvent) => boolean;
}): Promise<RoomEvent> {
  let targetCb;
  try {
    return await new Promise((resolve) => {
      void details.lookAfterEvent().then((afterEventId: string | undefined) => {
        // if the event has returned an event id, then we will wait for that in the timeline,
        // otherwise the "event" isn't a matrix event and we just have to start looking right away.
        let isAfterEventId = afterEventId === undefined;
        targetCb = (roomId: string, event: RoomEvent) => {
          if (event["event_id"] === afterEventId) {
            isAfterEventId = true;
            return;
          }
          if (isAfterEventId && details.predicate(event)) {
            resolve(event);
          }
        };
        details.matrix.on("room.event", targetCb);
      });
    });
  } finally {
    // unless i'm dumb, the type inference for this is wrong, and i don't know why.
    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
    if (targetCb) {
      details.matrix.off("room.event", targetCb);
    }
  }
}

/**
 * Create a new banlist for draupnir to watch and return the shortcode that can be used to refer to the list in future commands.
 * @param managementRoom The room to send the create command to.
 * @param mjolnir A syncing matrix client.
 * @param client A client that isn't draupnir to send the message with, as you will be invited to the room.
 * @returns The shortcode for the list that can be used to refer to the list in future commands.
 */
export async function createBanList(
  managementRoom: string,
  mjolnir: MatrixEmitter,
  client: MatrixClient
): Promise<string> {
  const listName = crypto.randomUUID();
  const listCreationResponse = await getFirstReply(
    mjolnir,
    managementRoom,
    async () => {
      return await client.sendMessage(managementRoom, {
        msgtype: "m.text",
        body: `!draupnir list create ${listName} ${listName}`,
      });
    }
  );
  assert.equal(
    listCreationResponse.content.body.includes(
      "This list is now being watched."
    ),
    true,
    "could not create a list to test with."
  );
  return listName;
}

export async function sendCommand(
  draupnir: Draupnir,
  command: string
): Promise<{ eventID: StringEventID }> {
  const eventID = (await draupnir.client.sendMessage(
    draupnir.managementRoomID,
    {
      msgtype: "m.text",
      body: command,
    }
  )) as StringEventID;
  return { eventID };
}

export async function acceptPropmt(
  client: MatrixSendClient,
  roomID: StringRoomID,
  eventID: StringEventID,
  promptKey: string
): Promise<void> {
  // i suspect that adding a reaction using the unstable API doesn't work because it uses the usntable prefix
  // whereas our schema doesn't have the unstable event type.
  // we don't test for this anywhere and we should really unify the situation between draupnir, draupnir safe mode,
  // and any new bots that just need all the same things.
  await client.unstableApis.addReactionToEvent(roomID, eventID, promptKey);
}