/*
Copyright 2020 Bruno Windels <bruno@windels.cloud>
Copyright 2020 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import {HomeServerError, ConnectionError} from "../error.js";
import {encodeQueryParams} from "./common.js";

class RequestWrapper {
    constructor(method, url, requestResult) {
        this._requestResult = requestResult;
        this._promise = requestResult.response().then(response => {
            // ok?
            if (response.status >= 200 && response.status < 300) {
                return response.body;
            } else {
                if (response.status >= 400 && !response.body?.errcode) {
                    throw new ConnectionError(`HTTP error status ${response.status} without errcode in body, assume this is a load balancer complaining the server is offline.`);
                } else {
                    throw new HomeServerError(method, url, response.body, response.status);
                }
            }
        }, err => {
            // if this._requestResult is still set, the abort error came not from calling abort here
            if (err.name === "AbortError" && this._requestResult) {
                throw new Error(`Request ${method} ${url} was unexpectedly aborted, see #187.`);
            } else {
                throw err;
            }
        });
    }

    abort() {
        if (this._requestResult) {
            this._requestResult.abort();
            // to mark that it was on purpose in above rejection handler
            this._requestResult = null;
        }
    }

    response() {
        return this._promise;
    }
}

function encodeBody(body) {
    if (body.nativeBlob && body.mimeType) {
        const blob = body;
        return {
            mimeType: blob.mimeType,
            body: blob, // will be unwrapped in request fn
            length: blob.size
        };
    } else if (typeof body === "object") {
        const json = JSON.stringify(body);
        return {
            mimeType: "application/json",
            body: json,
            length: body.length
        };
    } else {
        throw new Error("Unknown body type: " + body);
    }
}

export class HomeServerApi {
    constructor({homeServer, accessToken, request, createTimeout, reconnector}) {
        // store these both in a closure somehow so it's harder to get at in case of XSS?
        // one could change the homeserver as well so the token gets sent there, so both must be protected from read/write
        this._homeserver = homeServer;
        this._accessToken = accessToken;
        this._requestFn = request;
        this._createTimeout = createTimeout;
        this._reconnector = reconnector;
    }

    _url(csPath) {
        return `${this._homeserver}/_matrix/client/r0${csPath}`;
    }

    _baseRequest(method, url, queryParams, body, options, accessToken) {
        const queryString = encodeQueryParams(queryParams);
        url = `${url}?${queryString}`;
        let encodedBody;
        const headers = new Map();
        if (accessToken) {
            headers.set("Authorization", `Bearer ${accessToken}`);
        }
        headers.set("Accept", "application/json");
        if (body) {
            const encoded = encodeBody(body);
            headers.set("Content-Type", encoded.mimeType);
            headers.set("Content-Length", encoded.length);
            encodedBody = encoded.body;
        }
        const requestResult = this._requestFn(url, {
            method,
            headers,
            body: encodedBody,
            timeout: options?.timeout,
            format: "json"  // response format
        });

        const wrapper = new RequestWrapper(method, url, requestResult);
        
        if (this._reconnector) {
            wrapper.response().catch(err => {
                // Some endpoints such as /sync legitimately time-out
                // (which is also reported as a ConnectionError) and will re-attempt,
                // but spinning up the reconnector in this case is ok,
                // as all code ran on session and sync start should be reentrant
                if (err.name === "ConnectionError") {
                    this._reconnector.onRequestFailed(this);
                }
            });
        }

        return wrapper;
    }

    _unauthedRequest(method, url, queryParams, body, options) {
        return this._baseRequest(method, url, queryParams, body, options, null);
    }

    _authedRequest(method, url, queryParams, body, options) {
        return this._baseRequest(method, url, queryParams, body, options, this._accessToken);
    }

    _post(csPath, queryParams, body, options) {
        return this._authedRequest("POST", this._url(csPath), queryParams, body, options);
    }

    _put(csPath, queryParams, body, options) {
        return this._authedRequest("PUT", this._url(csPath), queryParams, body, options);
    }

    _get(csPath, queryParams, body, options) {
        return this._authedRequest("GET", this._url(csPath), queryParams, body, options);
    }

    sync(since, filter, timeout, options = null) {
        return this._get("/sync", {since, timeout, filter}, null, options);
    }

    // params is from, dir and optionally to, limit, filter.
    messages(roomId, params, options = null) {
        return this._get(`/rooms/${encodeURIComponent(roomId)}/messages`, params, null, options);
    }

    // params is at, membership and not_membership
    members(roomId, params, options = null) {
        return this._get(`/rooms/${encodeURIComponent(roomId)}/members`, params, null, options);
    }

    send(roomId, eventType, txnId, content, options = null) {
        return this._put(`/rooms/${encodeURIComponent(roomId)}/send/${encodeURIComponent(eventType)}/${encodeURIComponent(txnId)}`, {}, content, options);
    }

    receipt(roomId, receiptType, eventId, options = null) {
        return this._post(`/rooms/${encodeURIComponent(roomId)}/receipt/${encodeURIComponent(receiptType)}/${encodeURIComponent(eventId)}`,
            {}, {}, options);
    }

    passwordLogin(username, password, initialDeviceDisplayName, options = null) {
        return this._unauthedRequest("POST", this._url("/login"), null, {
          "type": "m.login.password",
          "identifier": {
            "type": "m.id.user",
            "user": username
          },
          "password": password,
          "initial_device_display_name": initialDeviceDisplayName
        }, options);
    }

    createFilter(userId, filter, options = null) {
        return this._post(`/user/${encodeURIComponent(userId)}/filter`, null, filter, options);
    }

    versions(options = null) {
        return this._unauthedRequest("GET", `${this._homeserver}/_matrix/client/versions`, null, null, options);
    }

    uploadKeys(payload, options = null) {
        return this._post("/keys/upload", null, payload, options);
    }

    queryKeys(queryRequest, options = null) {
        return this._post("/keys/query", null, queryRequest, options);
    }

    claimKeys(payload, options = null) {
        return this._post("/keys/claim", null, payload, options);
    }

    sendToDevice(type, payload, txnId, options = null) {
        return this._put(`/sendToDevice/${encodeURIComponent(type)}/${encodeURIComponent(txnId)}`, null, payload, options);
    }
    
    roomKeysVersion(version = null, options = null) {
        let versionPart = "";
        if (version) {
            versionPart = `/${encodeURIComponent(version)}`;
        }
        return this._get(`/room_keys/version${versionPart}`, null, null, options);
    }

    roomKeyForRoomAndSession(version, roomId, sessionId, options = null) {
        return this._get(`/room_keys/keys/${encodeURIComponent(roomId)}/${encodeURIComponent(sessionId)}`, {version}, null, options);
    }
}

export function tests() {
    function createRequestMock(result) {
        return function() {
            return {
                abort() {},
                response() {
                    return Promise.resolve(result);
                }
            }
        }
    }

    return {
        "superficial happy path for GET": async assert => {
            const hsApi = new HomeServerApi({
                request: createRequestMock({body: 42, status: 200}),
                homeServer: "https://hs.tld"
            });
            const result = await hsApi._get("foo", null, null, null).response();
            assert.strictEqual(result, 42);
        }
    }
}