let actionsQueue = {};
let defaultMaxActionsProgressing = 50;
let lastActionId = 0;

export const getQueue = (key) => {
    if (!actionsQueue[key]) {
        actionsQueue[key] = {
            max: defaultMaxActionsProgressing,
            actions: []
        };
    }
    return actionsQueue[key];
};

export const setMax = (key, max) => {
    getQueue(key).max = max;
};

const removeFromQueue = (key, id) => {
    let q = getQueue(key);
    q.actions = q.actions.filter(a => a.id !== id);
};

const execute = (key, action) => {
    // setting action to progressing
    action.progressing = true;
    action.fn(() => {
        removeFromQueue(key, action.id);
        executeQueue(key);
    });
};

const executeQueue = (key) => {
    let q = getQueue(key);
    const actualProgressing = q.actions.filter(a => a.progressing).length;
    if (q.actions.length === 0 || actualProgressing >= q.max) {
        return;
    }
    q.actions
        .filter(a => !a.progressing)
        .slice(0, q.max - actualProgressing)
        .map(action => execute(key, action));
};

export const addToExecute = (key, fn) => {
    let q = getQueue(key);
    q.actions.push({
        id: lastActionId,
        key,
        fn,
        progressing: false
    });
    lastActionId++;
    executeQueue(key);
};

// WYWOŁANIE

setMax('test-key', 4);

console.time('1')
console.time('2')
console.time('3')
console.time('4')
console.time('5')

// PIERWSZE WYWOŁANIE
addToExecute('test-key', (end) => {
  setTimeout(() => {
    console.timeEnd('1');
    end()
  }, 200);
})

// DRUGIE WYWOŁANIE
addToExecute('test-key', (end) => {
  setTimeout(() => {
    console.timeEnd('2');
    end()
  }, 200);
})

// TRZECIE WYWOŁANIE
addToExecute('test-key', (end) => {
  setTimeout(() => {
    console.timeEnd('3');
    end()
  }, 200);
})

addToExecute('test-key', (end) => {
  setTimeout(() => {
    console.timeEnd('4');
    end()
  }, 200);
})

addToExecute('test-key', (end) => {
  setTimeout(() => {
    console.timeEnd('5');
    end()
  }, 200);
})