//
// Utilities related to background operations while other operations are working
//

import {ShardingTest} from "jstests/libs/shardingtest.js";

/**
 * Allows synchronization between background ops and the test operations
 */
export var waitForLock = function (mongo, name) {
    let ts = new ObjectId();
    let lockColl = mongo.getCollection("config.testLocks");

    lockColl.update({_id: name, state: 0}, {$set: {state: 0}}, true);

    //
    // Wait until we can set the state to 1 with our id
    //

    let startTime = new Date().getTime();

    assert.soon(
        function () {
            let res = lockColl.update({_id: name, state: 0}, {$set: {ts: ts, state: 1}});

            if (new Date().getTime() - startTime > 20 * 1000) {
                jsTest.log.info("Waiting for...");
                jsTest.log.info({res});
                jsTest.log.info({lockColl: lockColl.findOne()});
                jsTest.log.info({ts});
            }

            return res.nModified == 1;
        },
        "could not acquire lock",
        30 * 1000,
        100,
    );

    jsTest.log.info("Acquired lock", {lock: {_id: name, ts: ts}, curr: lockColl.findOne({_id: name})});

    // Set the state back to 0
    let unlock = function () {
        jsTest.log.info("Releasing lock", {lock: {_id: name, ts: ts}, curr: lockColl.findOne({_id: name})});
        lockColl.update({_id: name, ts: ts}, {$set: {state: 0}});
    };

    // Return an object we can invoke unlock on
    return {unlock: unlock};
};

/**
 * Allows a test or background op to say it's finished
 */
export var setFinished = function (mongo, name, finished) {
    if (finished || finished == undefined)
        mongo.getCollection("config.testFinished").update({_id: name}, {_id: name}, true);
    else mongo.getCollection("config.testFinished").remove({_id: name});
};

/**
 * Checks whether a test or background op is finished
 */
export var isFinished = function (mongo, name) {
    return mongo.getCollection("config.testFinished").findOne({_id: name}) != null;
};

/**
 * Sets the result of a background op
 */
export var setResult = function (mongo, name, result, err) {
    mongo.getCollection("config.testResult").update({_id: name}, {_id: name, result: result, err: err}, true);
};

/**
 * Gets the result for a background op
 */
export var getResult = function (mongo, name) {
    return mongo.getCollection("config.testResult").findOne({_id: name});
};

export var startParallelOps = function (mongo, proc, args, context) {
    let procName = proc.name + "-" + new ObjectId();
    let seed = new ObjectId(new ObjectId().valueOf().split("").reverse().join("")).getTimestamp().getTime();

    // Make sure we aren't finished before we start
    setFinished(mongo, procName, false);
    setResult(mongo, procName, undefined, undefined);

    // TODO: Make this a context of its own
    let procContext = {
        procName: procName,
        seed: seed,
        waitForLock: waitForLock,
        setFinished: setFinished,
        isFinished: isFinished,
        setResult: setResult,

        setup: function (context, stored) {
            globalThis.waitForLock = function () {
                return context.waitForLock(db.getMongo(), context.procName);
            };
            globalThis.setFinished = function (finished) {
                return context.setFinished(db.getMongo(), context.procName, finished);
            };
            globalThis.isFinished = function () {
                return context.isFinished(db.getMongo(), context.procName);
            };
            globalThis.setResult = function (result, err) {
                return context.setResult(db.getMongo(), context.procName, result, err);
            };
        },
    };

    let bootstrapper = function (stored) {
        let procContext = stored.procContext;
        eval("procContext = " + procContext);
        procContext.setup(procContext, stored);

        let contexts = stored.contexts;
        eval("contexts = " + contexts);

        for (let i = 0; i < contexts.length; i++) {
            if (typeof contexts[i] != "undefined") {
                // Evaluate all contexts
                contexts[i](procContext);
            }
        }

        let operation = stored.operation;
        eval("operation = " + operation);

        let args = stored.args;
        eval("args = " + args);

        let result = undefined;
        let err = undefined;

        try {
            result = operation.apply(null, args);
        } catch (e) {
            err = e;
        }

        setResult(result, err);
    };

    let contexts = [RandomFunctionContext, context];

    let testDataColl = mongo.getCollection("config.parallelTest");

    assert.commandWorked(
        testDataColl.insert({
            _id: procName,
            bootstrapper: tojson(bootstrapper),
            operation: tojson(proc),
            args: tojson(args),
            procContext: tojson(procContext),
            contexts: tojson(contexts),
        }),
    );

    let bootstrapStartup =
        "{ var procName = '" +
        procName +
        "'; " +
        "var stored = db.getMongo().getCollection( '" +
        testDataColl +
        "' )" +
        ".findOne({ _id : procName }); " +
        "var bootstrapper = stored.bootstrapper; " +
        "eval( 'bootstrapper = ' + bootstrapper ); " +
        "bootstrapper( stored ); " +
        "}";

    // Save the global db object if it exists, so that we can restore it after starting the parallel
    // shell.
    let oldDB = undefined;
    if (typeof db !== "undefined") {
        oldDB = db;
    }
    globalThis.db = mongo.getDB("test");

    jsTest.log("Starting " + proc.name + " operations...");

    let rawJoin = startParallelShell(bootstrapStartup);

    globalThis.db = oldDB;

    let join = function (options = {}) {
        const {checkExitSuccess = true} = options;
        delete options.checkExitSuccess;
        setFinished(mongo, procName, true);

        rawJoin(options);

        let result = getResult(mongo, procName);

        assert.neq(result, null);

        if (!checkExitSuccess) {
            return result;
        } else if (checkExitSuccess && result.err) {
            throw Error("Error in parallel ops " + procName + " : " + tojson(result.err));
        } else {
            return result.result;
        }
    };

    return join;
};

export var RandomFunctionContext = function (context) {
    Random.srand(context.seed);

    Random.randBool = function () {
        return Random.rand() > 0.5;
    };

    Random.randInt = function (min, max) {
        if (max == undefined) {
            max = min;
            min = 0;
        }

        return min + Math.floor(Random.rand() * max);
    };

    Random.randShardKey = function () {
        let numFields = 2; // Random.randInt(1, 3)

        let key = {};
        for (let i = 0; i < numFields; i++) {
            let field = String.fromCharCode("a".charCodeAt() + i);
            key[field] = 1;
        }

        return key;
    };

    Random.randShardKeyValue = function (shardKey) {
        let keyValue = {};
        for (let field in shardKey) {
            keyValue[field] = Random.randInt(1, 100);
        }

        return keyValue;
    };

    Random.randCluster = function () {
        let numShards = 2; // Random.randInt( 1, 10 )
        const rs = false; // Random.randBool()
        let st = new ShardingTest({shards: numShards, mongos: 4, other: {rs: rs}});

        return st;
    };
};

//
// Some utility operations
//

export function moveOps(collName, options) {
    options = options || {};

    let admin = db.getMongo().getDB("admin");
    let config = db.getMongo().getDB("config");
    let shards = config.shards.find().toArray();
    let shardKey = config.collections.findOne({_id: collName}).key;

    while (!isFinished()) {
        let findKey = Random.randShardKeyValue(shardKey);
        let toShard = shards[Random.randInt(shards.length)]._id;

        try {
            jsTest.log.info({res: admin.runCommand({moveChunk: collName, find: findKey, to: toShard})});
        } catch (e) {
            jsTest.log.info({error: e});
        }

        sleep(1000);
    }

    jsTest.log("Stopping moveOps...");
}

export function splitOps(collName, options) {
    options = options || {};

    let admin = db.getMongo().getDB("admin");
    let config = db.getMongo().getDB("config");
    let shards = config.shards.find().toArray();
    let shardKey = config.collections.findOne({_id: collName}).key;

    while (!isFinished()) {
        let middleKey = Random.randShardKeyValue(shardKey);

        try {
            jsTest.log.info({res: admin.runCommand({split: collName, middle: middleKey})});
        } catch (e) {
            jsTest.log.info({error: e});
        }

        sleep(1000);
    }

    jsTest.log("Stopping splitOps...");
}