redux-devtools/packages/redux-devtools-instrument/src/instrument.ts

import difference from 'lodash/difference';
import union from 'lodash/union';
import isPlainObject from 'lodash/isPlainObject';
import {
  Action,
  Observer,
  PreloadedState,
  Reducer,
  Store,
  StoreEnhancer,
  StoreEnhancerStoreCreator,
} from 'redux';
import getSymbolObservable from './getSymbolObservable';

export const ActionTypes = {
  PERFORM_ACTION: 'PERFORM_ACTION',
  RESET: 'RESET',
  ROLLBACK: 'ROLLBACK',
  COMMIT: 'COMMIT',
  SWEEP: 'SWEEP',
  TOGGLE_ACTION: 'TOGGLE_ACTION',
  SET_ACTIONS_ACTIVE: 'SET_ACTIONS_ACTIVE',
  JUMP_TO_STATE: 'JUMP_TO_STATE',
  JUMP_TO_ACTION: 'JUMP_TO_ACTION',
  REORDER_ACTION: 'REORDER_ACTION',
  IMPORT_STATE: 'IMPORT_STATE',
  LOCK_CHANGES: 'LOCK_CHANGES',
  PAUSE_RECORDING: 'PAUSE_RECORDING',
} as const;

const isChrome =
  typeof window === 'object' &&
  (typeof (window as typeof window & { chrome: unknown }).chrome !==
    'undefined' ||
    (typeof window.process !== 'undefined' &&
      (window.process as typeof window.process & { type: unknown }).type ===
        'renderer'));

const isChromeOrNode =
  isChrome ||
  (typeof process !== 'undefined' &&
    process.release &&
    process.release.name === 'node');

export interface PerformAction<A extends Action<string>> {
  type: typeof ActionTypes.PERFORM_ACTION;
  action: A;
  timestamp: number;
  stack: string | undefined;
}

interface ResetAction {
  type: typeof ActionTypes.RESET;
  timestamp: number;
}

interface RollbackAction {
  type: typeof ActionTypes.ROLLBACK;
  timestamp: number;
}

interface CommitAction {
  type: typeof ActionTypes.COMMIT;
  timestamp: number;
}

interface SweepAction {
  type: typeof ActionTypes.SWEEP;
}

interface ToggleAction {
  type: typeof ActionTypes.TOGGLE_ACTION;
  id: number;
}

interface SetActionsActiveAction {
  type: typeof ActionTypes.SET_ACTIONS_ACTIVE;
  start: number;
  end: number;
  active: boolean;
}

interface ReorderAction {
  type: typeof ActionTypes.REORDER_ACTION;
  actionId: number;
  beforeActionId: number;
}

interface JumpToStateAction {
  type: typeof ActionTypes.JUMP_TO_STATE;
  index: number;
}

interface JumpToActionAction {
  type: typeof ActionTypes.JUMP_TO_ACTION;
  actionId: number;
}

interface ImportStateAction<S, A extends Action<string>, MonitorState> {
  type: typeof ActionTypes.IMPORT_STATE;
  nextLiftedState: LiftedState<S, A, MonitorState> | readonly A[];
  preloadedState?: S;
  noRecompute?: boolean | undefined;
}

interface LockChangesAction {
  type: typeof ActionTypes.LOCK_CHANGES;
  status: boolean;
}

interface PauseRecordingAction {
  type: typeof ActionTypes.PAUSE_RECORDING;
  status: boolean;
}

export type LiftedAction<S, A extends Action<string>, MonitorState> =
  | PerformAction<A>
  | ResetAction
  | RollbackAction
  | CommitAction
  | SweepAction
  | ToggleAction
  | SetActionsActiveAction
  | ReorderAction
  | JumpToStateAction
  | JumpToActionAction
  | ImportStateAction<S, A, MonitorState>
  | LockChangesAction
  | PauseRecordingAction;

/**
 * Action creators to change the History state.
 */
export const ActionCreators = {
  performAction<A extends Action<string>>(
    this: void,
    action: A,
    trace?: ((action: A) => string | undefined) | boolean,
    traceLimit?: number,
    // eslint-disable-next-line @typescript-eslint/ban-types
    toExcludeFromTrace?: Function,
  ) {
    if (!isPlainObject(action)) {
      throw new Error(
        'Actions must be plain objects. ' +
          'Use custom middleware for async actions.',
      );
    }

    if (typeof action.type === 'undefined') {
      throw new Error(
        'Actions may not have an undefined "type" property. ' +
          'Have you misspelled a constant?',
      );
    }

    let stack;
    if (trace) {
      let extraFrames = 0;
      if (typeof trace === 'function') {
        stack = trace(action);
      } else {
        const error = Error();
        let prevStackTraceLimit;
        if (Error.captureStackTrace && isChromeOrNode) {
          // avoid error-polyfill
          if (traceLimit && Error.stackTraceLimit < traceLimit) {
            prevStackTraceLimit = Error.stackTraceLimit;
            Error.stackTraceLimit = traceLimit;
          }
          Error.captureStackTrace(error, toExcludeFromTrace);
        } else {
          extraFrames = 3;
        }
        stack = error.stack;
        if (prevStackTraceLimit) Error.stackTraceLimit = prevStackTraceLimit;
        if (
          extraFrames ||
          typeof Error.stackTraceLimit !== 'number' ||
          (traceLimit && Error.stackTraceLimit > traceLimit)
        ) {
          if (stack != null) {
            const frames = stack.split('\n');
            if (traceLimit && frames.length > traceLimit) {
              stack = frames
                .slice(
                  0,
                  traceLimit +
                    extraFrames +
                    (frames[0].startsWith('Error') ? 1 : 0),
                )
                .join('\n');
            }
          }
        }
      }
    }

    return {
      type: ActionTypes.PERFORM_ACTION,
      action,
      timestamp: Date.now(),
      stack,
    };
  },

  reset(this: void): ResetAction {
    return { type: ActionTypes.RESET, timestamp: Date.now() };
  },

  rollback(this: void): RollbackAction {
    return { type: ActionTypes.ROLLBACK, timestamp: Date.now() };
  },

  commit(this: void): CommitAction {
    return { type: ActionTypes.COMMIT, timestamp: Date.now() };
  },

  sweep(this: void): SweepAction {
    return { type: ActionTypes.SWEEP };
  },

  toggleAction(this: void, id: number): ToggleAction {
    return { type: ActionTypes.TOGGLE_ACTION, id };
  },

  setActionsActive(
    this: void,
    start: number,
    end: number,
    active = true,
  ): SetActionsActiveAction {
    return { type: ActionTypes.SET_ACTIONS_ACTIVE, start, end, active };
  },

  reorderAction(
    this: void,
    actionId: number,
    beforeActionId: number,
  ): ReorderAction {
    return { type: ActionTypes.REORDER_ACTION, actionId, beforeActionId };
  },

  jumpToState(this: void, index: number): JumpToStateAction {
    return { type: ActionTypes.JUMP_TO_STATE, index };
  },

  jumpToAction(this: void, actionId: number): JumpToActionAction {
    return { type: ActionTypes.JUMP_TO_ACTION, actionId };
  },

  importState<S, A extends Action<string>, MonitorState = null>(
    this: void,
    nextLiftedState: LiftedState<S, A, MonitorState> | readonly A[],
    noRecompute?: boolean,
  ): ImportStateAction<S, A, MonitorState> {
    return { type: ActionTypes.IMPORT_STATE, nextLiftedState, noRecompute };
  },

  lockChanges(this: void, status: boolean): LockChangesAction {
    return { type: ActionTypes.LOCK_CHANGES, status };
  },

  pauseRecording(this: void, status: boolean): PauseRecordingAction {
    return { type: ActionTypes.PAUSE_RECORDING, status };
  },
};

export const INIT_ACTION = { type: '@@INIT' };

/**
 * Computes the next entry with exceptions catching.
 */
function computeWithTryCatch<S, A extends Action<string>>(
  reducer: Reducer<S, A>,
  action: A,
  state: S,
) {
  let nextState = state;
  let nextError;
  try {
    nextState = reducer(state, action);
  } catch (err) {
    // eslint-disable-next-line @typescript-eslint/ban-types
    nextError = (err as object).toString();
    if (isChrome) {
      // In Chrome, rethrowing provides better source map support
      setTimeout(() => {
        throw err;
      });
    } else {
      console.error(err); // eslint-disable-line no-console
    }
  }

  return {
    state: nextState,
    error: nextError,
  };
}

/**
 * Computes the next entry in the log by applying an action.
 */
function computeNextEntry<S, A extends Action<string>>(
  reducer: Reducer<S, A>,
  action: A,
  state: S,
  shouldCatchErrors: boolean | undefined,
) {
  if (!shouldCatchErrors) {
    return { state: reducer(state, action) };
  }
  return computeWithTryCatch(reducer, action, state);
}

/**
 * Runs the reducer on invalidated actions to get a fresh computation log.
 */
function recomputeStates<S, A extends Action<string>>(
  computedStates: { state: S; error?: string }[],
  minInvalidatedStateIndex: number,
  reducer: Reducer<S, A>,
  committedState: S,
  actionsById: { [actionId: number]: PerformAction<A> },
  stagedActionIds: number[],
  skippedActionIds: number[],
  shouldCatchErrors: boolean | undefined,
) {
  // Optimization: exit early and return the same reference
  // if we know nothing could have changed.
  if (
    !computedStates ||
    minInvalidatedStateIndex === -1 ||
    (minInvalidatedStateIndex >= computedStates.length &&
      computedStates.length === stagedActionIds.length)
  ) {
    return computedStates;
  }

  const nextComputedStates = computedStates.slice(0, minInvalidatedStateIndex);
  for (let i = minInvalidatedStateIndex; i < stagedActionIds.length; i++) {
    const actionId = stagedActionIds[i];
    const action = actionsById[actionId].action;

    const previousEntry = nextComputedStates[i - 1];
    const previousState = previousEntry ? previousEntry.state : committedState;

    const shouldSkip = skippedActionIds.indexOf(actionId) > -1;
    let entry;
    if (shouldSkip) {
      entry = previousEntry;
    } else {
      if (shouldCatchErrors && previousEntry && previousEntry.error) {
        entry = {
          state: previousState,
          error: 'Interrupted by an error up the chain',
        };
      } else {
        entry = computeNextEntry(
          reducer,
          action,
          previousState,
          shouldCatchErrors,
        );
      }
    }
    nextComputedStates.push(entry);
  }

  return nextComputedStates;
}

/**
 * Lifts an app's action into an action on the lifted store.
 */
function liftAction<A extends Action<string>>(
  action: A,
  trace?: ((action: A) => string | undefined) | boolean,
  traceLimit?: number,
  // eslint-disable-next-line @typescript-eslint/ban-types
  toExcludeFromTrace?: Function,
) {
  return ActionCreators.performAction(
    action,
    trace,
    traceLimit,
    toExcludeFromTrace,
  );
}

function isArray<S, A extends Action<string>, MonitorState>(
  nextLiftedState: LiftedState<S, A, MonitorState> | readonly A[],
): nextLiftedState is readonly A[] {
  return Array.isArray(nextLiftedState);
}

export interface LiftedState<S, A extends Action<string>, MonitorState> {
  monitorState: MonitorState;
  nextActionId: number;
  actionsById: { [actionId: number]: PerformAction<A> };
  stagedActionIds: number[];
  skippedActionIds: number[];
  committedState: S;
  currentStateIndex: number;
  computedStates: { state: S; error?: string }[];
  isLocked: boolean;
  isPaused: boolean;
}

/**
 * Creates a history state reducer from an app's reducer.
 */
function liftReducerWith<
  S,
  A extends Action<string>,
  MonitorState,
  MonitorAction extends Action<string>,
>(
  reducer: Reducer<S, A>,
  initialCommittedState: PreloadedState<S> | undefined,
  monitorReducer: Reducer<MonitorState, MonitorAction>,
  options: Options<S, A, MonitorState, MonitorAction>,
): Reducer<LiftedState<S, A, MonitorState>, LiftedAction<S, A, MonitorState>> {
  const initialLiftedState: LiftedState<S, A, MonitorState> = {
    monitorState: monitorReducer(undefined, {} as MonitorAction),
    nextActionId: 1,
    actionsById: { 0: liftAction(INIT_ACTION as A) },
    stagedActionIds: [0],
    skippedActionIds: [],
    committedState: initialCommittedState as S,
    currentStateIndex: 0,
    computedStates: [],
    isLocked: options.shouldStartLocked === true,
    isPaused: options.shouldRecordChanges === false,
  };

  /**
   * Manages how the history actions modify the history state.
   */
  return (
    liftedState: LiftedState<S, A, MonitorState> | undefined,
    liftedAction: LiftedAction<S, A, MonitorState>,
  ): LiftedState<S, A, MonitorState> => {
    let {
      monitorState,
      actionsById,
      nextActionId,
      stagedActionIds,
      skippedActionIds,
      committedState,
      currentStateIndex,
      computedStates,
      isLocked,
      isPaused,
    } = liftedState || initialLiftedState;

    if (!liftedState) {
      // Prevent mutating initialLiftedState
      actionsById = { ...actionsById };
    }

    function commitExcessActions(n: number) {
      // Auto-commits n-number of excess actions.
      let excess = n;
      let idsToDelete = stagedActionIds.slice(1, excess + 1);

      for (let i = 0; i < idsToDelete.length; i++) {
        if (computedStates[i + 1].error) {
          // Stop if error is found. Commit actions up to error.
          excess = i;
          idsToDelete = stagedActionIds.slice(1, excess + 1);
          break;
        } else {
          delete actionsById[idsToDelete[i]];
        }
      }

      skippedActionIds = skippedActionIds.filter(
        (id) => idsToDelete.indexOf(id) === -1,
      );
      stagedActionIds = [0, ...stagedActionIds.slice(excess + 1)];
      committedState = computedStates[excess].state;
      computedStates = computedStates.slice(excess);
      currentStateIndex =
        currentStateIndex > excess ? currentStateIndex - excess : 0;
    }

    function computePausedAction(
      shouldInit?: boolean,
    ): LiftedState<S, A, MonitorState> {
      let computedState;
      if (shouldInit) {
        computedState = computedStates[currentStateIndex];
        monitorState = monitorReducer(
          monitorState,
          liftedAction as MonitorAction,
        );
      } else {
        computedState = computeNextEntry(
          reducer,
          (liftedAction as PerformAction<A>).action,
          computedStates[currentStateIndex].state,
          false,
        );
      }
      if (!options.pauseActionType || nextActionId === 1) {
        return {
          monitorState,
          actionsById: { 0: liftAction(INIT_ACTION as A) },
          nextActionId: 1,
          stagedActionIds: [0],
          skippedActionIds: [],
          committedState: computedState.state,
          currentStateIndex: 0,
          computedStates: [computedState],
          isLocked,
          isPaused: true,
        };
      }
      if (shouldInit) {
        if (currentStateIndex === stagedActionIds.length - 1) {
          currentStateIndex++;
        }
        stagedActionIds = [...stagedActionIds, nextActionId];
        nextActionId++;
      }
      return {
        monitorState,
        actionsById: {
          ...actionsById,
          [nextActionId - 1]: liftAction({
            type: options.pauseActionType,
          } as A),
        },
        nextActionId,
        stagedActionIds,
        skippedActionIds,
        committedState,
        currentStateIndex,
        computedStates: [
          ...computedStates.slice(0, stagedActionIds.length - 1),
          computedState,
        ],
        isLocked,
        isPaused: true,
      };
    }

    // By default, aggressively recompute every state whatever happens.
    // This has O(n) performance, so we'll override this to a sensible
    // value whenever we feel like we don't have to recompute the states.
    let minInvalidatedStateIndex = 0;

    // maxAge number can be changed dynamically
    let maxAge = options.maxAge;
    if (typeof maxAge === 'function')
      maxAge = maxAge(liftedAction, liftedState);

    if (/^@@redux\/(INIT|REPLACE)/.test(liftedAction.type)) {
      if (options.shouldHotReload === false) {
        actionsById = { 0: liftAction(INIT_ACTION as A) };
        nextActionId = 1;
        stagedActionIds = [0];
        skippedActionIds = [];
        committedState =
          computedStates.length === 0
            ? (initialCommittedState as S)
            : computedStates[currentStateIndex].state;
        currentStateIndex = 0;
        computedStates = [];
      }

      // Recompute states on hot reload and init.
      minInvalidatedStateIndex = 0;

      if (maxAge && stagedActionIds.length > maxAge) {
        // States must be recomputed before committing excess.
        computedStates = recomputeStates<S, A>(
          computedStates,
          minInvalidatedStateIndex,
          reducer,
          committedState,
          actionsById,
          stagedActionIds,
          skippedActionIds,
          options.shouldCatchErrors,
        );

        commitExcessActions(stagedActionIds.length - maxAge);

        // Avoid double computation.
        minInvalidatedStateIndex = Infinity;
      }
    } else {
      switch (liftedAction.type) {
        case ActionTypes.PERFORM_ACTION: {
          if (isLocked) return liftedState || initialLiftedState;
          if (isPaused) return computePausedAction();

          // Auto-commit as new actions come in.
          if (maxAge && stagedActionIds.length >= maxAge) {
            commitExcessActions(stagedActionIds.length - maxAge + 1);
          }

          if (currentStateIndex === stagedActionIds.length - 1) {
            currentStateIndex++;
          }
          const actionId = nextActionId++;
          // Mutation! This is the hottest path, and we optimize on purpose.
          // It is safe because we set a new key in a cache dictionary.
          actionsById[actionId] = liftedAction;
          stagedActionIds = [...stagedActionIds, actionId];
          // Optimization: we know that only the new action needs computing.
          minInvalidatedStateIndex = stagedActionIds.length - 1;
          break;
        }
        case ActionTypes.RESET: {
          // Get back to the state the store was created with.
          actionsById = { 0: liftAction(INIT_ACTION as A) };
          nextActionId = 1;
          stagedActionIds = [0];
          skippedActionIds = [];
          committedState = initialCommittedState as S;
          currentStateIndex = 0;
          computedStates = [];
          break;
        }
        case ActionTypes.COMMIT: {
          // Consider the last committed state the new starting point.
          // Squash any staged actions into a single committed state.
          actionsById = { 0: liftAction(INIT_ACTION as A) };
          nextActionId = 1;
          stagedActionIds = [0];
          skippedActionIds = [];
          committedState = computedStates[currentStateIndex].state;
          currentStateIndex = 0;
          computedStates = [];
          break;
        }
        case ActionTypes.ROLLBACK: {
          // Forget about any staged actions.
          // Start again from the last committed state.
          actionsById = { 0: liftAction(INIT_ACTION as A) };
          nextActionId = 1;
          stagedActionIds = [0];
          skippedActionIds = [];
          currentStateIndex = 0;
          computedStates = [];
          break;
        }
        case ActionTypes.TOGGLE_ACTION: {
          // Toggle whether an action with given ID is skipped.
          // Being skipped means it is a no-op during the computation.
          const { id: actionId } = liftedAction;
          const index = skippedActionIds.indexOf(actionId);
          if (index === -1) {
            skippedActionIds = [actionId, ...skippedActionIds];
          } else {
            skippedActionIds = skippedActionIds.filter((id) => id !== actionId);
          }
          // Optimization: we know history before this action hasn't changed
          minInvalidatedStateIndex = stagedActionIds.indexOf(actionId);
          break;
        }
        case ActionTypes.SET_ACTIONS_ACTIVE: {
          // Toggle whether an action with given ID is skipped.
          // Being skipped means it is a no-op during the computation.
          const { start, end, active } = liftedAction;
          const actionIds = [];
          for (let i = start; i < end; i++) actionIds.push(i);
          if (active) {
            skippedActionIds = difference(skippedActionIds, actionIds);
          } else {
            skippedActionIds = union(skippedActionIds, actionIds);
          }

          // Optimization: we know history before this action hasn't changed
          minInvalidatedStateIndex = stagedActionIds.indexOf(start);
          break;
        }
        case ActionTypes.JUMP_TO_STATE: {
          // Without recomputing anything, move the pointer that tell us
          // which state is considered the current one. Useful for sliders.
          currentStateIndex = liftedAction.index;
          // Optimization: we know the history has not changed.
          minInvalidatedStateIndex = Infinity;
          break;
        }
        case ActionTypes.JUMP_TO_ACTION: {
          // Jumps to a corresponding state to a specific action.
          // Useful when filtering actions.
          const index = stagedActionIds.indexOf(liftedAction.actionId);
          if (index !== -1) currentStateIndex = index;
          minInvalidatedStateIndex = Infinity;
          break;
        }
        case ActionTypes.SWEEP: {
          // Forget any actions that are currently being skipped.
          stagedActionIds = difference(stagedActionIds, skippedActionIds);
          skippedActionIds = [];
          currentStateIndex = Math.min(
            currentStateIndex,
            stagedActionIds.length - 1,
          );
          break;
        }
        case ActionTypes.REORDER_ACTION: {
          // Recompute actions in a new order.
          const actionId = liftedAction.actionId;
          const idx = stagedActionIds.indexOf(actionId);
          // do nothing in case the action is already removed or trying to move the first action
          if (idx < 1) break;
          const beforeActionId = liftedAction.beforeActionId;
          let newIdx = stagedActionIds.indexOf(beforeActionId);
          if (newIdx < 1) {
            // move to the beginning or to the end
            const count = stagedActionIds.length;
            newIdx = beforeActionId > stagedActionIds[count - 1] ? count : 1;
          }
          const diff = idx - newIdx;

          if (diff > 0) {
            // move left
            stagedActionIds = [
              ...stagedActionIds.slice(0, newIdx),
              actionId,
              ...stagedActionIds.slice(newIdx, idx),
              ...stagedActionIds.slice(idx + 1),
            ];
            minInvalidatedStateIndex = newIdx;
          } else if (diff < 0) {
            // move right
            stagedActionIds = [
              ...stagedActionIds.slice(0, idx),
              ...stagedActionIds.slice(idx + 1, newIdx),
              actionId,
              ...stagedActionIds.slice(newIdx),
            ];
            minInvalidatedStateIndex = idx;
          }
          break;
        }
        case ActionTypes.IMPORT_STATE: {
          if (isArray(liftedAction.nextLiftedState)) {
            // recompute array of actions
            actionsById = { 0: liftAction(INIT_ACTION as A) };
            nextActionId = 1;
            stagedActionIds = [0];
            skippedActionIds = [];
            currentStateIndex = liftedAction.nextLiftedState.length;
            computedStates = [];
            committedState = liftedAction.preloadedState as S;
            minInvalidatedStateIndex = 0;
            // iterate through actions
            liftedAction.nextLiftedState.forEach((action) => {
              actionsById[nextActionId] = liftAction(
                action,
                options.trace || options.shouldIncludeCallstack,
              );
              stagedActionIds.push(nextActionId);
              nextActionId++;
            });
          } else {
            // Completely replace everything.
            ({
              monitorState,
              actionsById,
              nextActionId,
              stagedActionIds,
              skippedActionIds,
              committedState,
              currentStateIndex,
              computedStates,
            } = liftedAction.nextLiftedState);

            if (liftedAction.noRecompute) {
              minInvalidatedStateIndex = Infinity;
            }
          }

          break;
        }
        case ActionTypes.LOCK_CHANGES: {
          isLocked = liftedAction.status;
          minInvalidatedStateIndex = Infinity;
          break;
        }
        case ActionTypes.PAUSE_RECORDING: {
          isPaused = liftedAction.status;
          if (isPaused) {
            return computePausedAction(true);
          }
          // Commit when unpausing
          actionsById = { 0: liftAction(INIT_ACTION as A) };
          nextActionId = 1;
          stagedActionIds = [0];
          skippedActionIds = [];
          committedState = computedStates[currentStateIndex].state;
          currentStateIndex = 0;
          computedStates = [];
          break;
        }
        default: {
          // If the action is not recognized, it's a monitor action.
          // Optimization: a monitor action can't change history.
          minInvalidatedStateIndex = Infinity;
          break;
        }
      }
    }

    computedStates = recomputeStates(
      computedStates,
      minInvalidatedStateIndex,
      reducer,
      committedState,
      actionsById,
      stagedActionIds,
      skippedActionIds,
      options.shouldCatchErrors,
    );
    monitorState = monitorReducer(monitorState, liftedAction as MonitorAction);
    return {
      monitorState,
      actionsById,
      nextActionId,
      stagedActionIds,
      skippedActionIds,
      committedState,
      currentStateIndex,
      computedStates,
      isLocked,
      isPaused,
    };
  };
}

/**
 * Provides an app's view into the state of the lifted store.
 */
function unliftState<S, A extends Action<string>, MonitorState, NextStateExt>(
  liftedState: LiftedState<S, A, MonitorState> & NextStateExt,
): S & NextStateExt {
  const { computedStates, currentStateIndex } = liftedState;
  const { state } = computedStates[currentStateIndex];
  return state as S & NextStateExt;
}

export type LiftedReducer<S, A extends Action<string>, MonitorState> = Reducer<
  LiftedState<S, A, MonitorState>,
  LiftedAction<S, A, MonitorState>
>;

export type LiftedStore<S, A extends Action<string>, MonitorState> = Store<
  LiftedState<S, A, MonitorState>,
  LiftedAction<S, A, MonitorState>
>;

export type InstrumentExt<S, A extends Action<string>, MonitorState> = {
  liftedStore: LiftedStore<S, A, MonitorState>;
};

export type EnhancedStore<S, A extends Action<string>, MonitorState> = Store<
  S,
  A
> &
  InstrumentExt<S, A, MonitorState>;

/**
 * Provides an app's view into the lifted store.
 */
function unliftStore<
  S,
  A extends Action<string>,
  MonitorState,
  MonitorAction extends Action<string>,
  NextExt,
  NextStateExt,
>(
  liftedStore: Store<
    LiftedState<S, A, MonitorState> & NextStateExt,
    LiftedAction<S, A, MonitorState>
  > &
    NextExt,
  liftReducer: (r: Reducer<S, A>) => LiftedReducer<S, A, MonitorState>,
  options: Options<S, A, MonitorState, MonitorAction>,
) {
  let lastDefinedState: S & NextStateExt;
  const trace = options.trace || options.shouldIncludeCallstack;
  const traceLimit = options.traceLimit || 10;

  function getState(): S & NextStateExt {
    const state = unliftState<S, A, MonitorState, NextStateExt>(
      liftedStore.getState(),
    );
    if (state !== undefined) {
      lastDefinedState = state;
    }
    return lastDefinedState;
  }

  function dispatch<T extends A>(action: T): T {
    liftedStore.dispatch(liftAction<A>(action, trace, traceLimit, dispatch));
    return action;
  }

  const $$observable = getSymbolObservable();
  if (!($$observable in liftedStore)) {
    console.warn(
      'Symbol.observable as defined by Redux and Redux DevTools do not match. This could cause your app to behave differently if the DevTools are not loaded. Consider polyfilling Symbol.observable before Redux is imported or avoid polyfilling Symbol.observable altogether.',
    );
  }

  return {
    liftedStore,

    dispatch,

    // eslint-disable-next-line @typescript-eslint/unbound-method
    subscribe: liftedStore.subscribe,

    getState,

    replaceReducer(nextReducer: Reducer<S & NextStateExt, A>) {
      liftedStore.replaceReducer(
        liftReducer(
          nextReducer as unknown as Reducer<S, A>,
        ) as unknown as Reducer<
          LiftedState<S, A, MonitorState> & NextStateExt,
          LiftedAction<S, A, MonitorState>
        >,
      );
    },

    [$$observable]() {
      return {
        subscribe(observer: Observer<S>) {
          if (typeof observer !== 'object') {
            throw new TypeError('Expected the observer to be an object.');
          }

          function observeState() {
            if (observer.next) {
              observer.next(getState());
            }
          }

          observeState();
          const unsubscribe = liftedStore.subscribe(observeState);
          return { unsubscribe };
        },

        [$$observable]() {
          return this;
        },
      };
    },
  } as unknown as Store<S & NextStateExt, A> &
    NextExt & {
      liftedStore: Store<
        LiftedState<S, A, MonitorState> & NextStateExt,
        LiftedAction<S, A, MonitorState>
      >;
    };
}

export interface Options<
  S,
  A extends Action<string>,
  MonitorState,
  MonitorAction extends Action<string>,
> {
  maxAge?:
    | number
    | ((
        currentLiftedAction: LiftedAction<S, A, MonitorState>,
        previousLiftedState: LiftedState<S, A, MonitorState> | undefined,
      ) => number);
  shouldCatchErrors?: boolean;
  shouldRecordChanges?: boolean;
  pauseActionType?: unknown;
  shouldStartLocked?: boolean;
  shouldHotReload?: boolean;
  trace?: boolean | ((action: A) => string | undefined);
  traceLimit?: number;
  shouldIncludeCallstack?: boolean;
}

/**
 * Redux instrumentation store enhancer.
 */
export function instrument<
  OptionsS,
  OptionsA extends Action<string>,
  MonitorState = null,
  MonitorAction extends Action<string> = never,
>(
  monitorReducer: Reducer<MonitorState, MonitorAction> = (() =>
    null) as unknown as Reducer<MonitorState, MonitorAction>,
  options: Options<OptionsS, OptionsA, MonitorState, MonitorAction> = {},
): StoreEnhancer<InstrumentExt<any, any, MonitorState>> {
  if (typeof options.maxAge === 'number' && options.maxAge < 2) {
    throw new Error(
      'DevTools.instrument({ maxAge }) option, if specified, ' +
        'may not be less than 2.',
    );
  }

  return <NextExt, NextStateExt>(
      createStore: StoreEnhancerStoreCreator<NextExt, NextStateExt>,
    ) =>
    <S, A extends Action<string>>(
      reducer: Reducer<S, A>,
      initialState?: PreloadedState<S>,
    ) => {
      function liftReducer(r: Reducer<S, A>) {
        if (typeof r !== 'function') {
          if (r && typeof (r as { default: unknown }).default === 'function') {
            throw new Error(
              'Expected the reducer to be a function. ' +
                'Instead got an object with a "default" field. ' +
                'Did you pass a module instead of the default export? ' +
                'Try passing require(...).default instead.',
            );
          }
          throw new Error('Expected the reducer to be a function.');
        }
        return liftReducerWith<S, A, MonitorState, MonitorAction>(
          r,
          initialState,
          monitorReducer,
          options as unknown as Options<S, A, MonitorState, MonitorAction>,
        );
      }

      const liftedStore = createStore(liftReducer(reducer));
      if (
        (
          liftedStore as Store<
            LiftedState<S, A, MonitorState> & NextStateExt,
            LiftedAction<S, A, MonitorState>
          > &
            NextExt & {
              liftedStore: Store<
                LiftedState<S, A, MonitorState>,
                LiftedAction<S, A, MonitorState>
              >;
            }
        ).liftedStore
      ) {
        throw new Error(
          'DevTools instrumentation should not be applied more than once. ' +
            'Check your store configuration.',
        );
      }

      return unliftStore<
        S,
        A,
        MonitorState,
        MonitorAction,
        NextExt,
        NextStateExt
      >(
        liftedStore,
        liftReducer,
        options as unknown as Options<S, A, MonitorState, MonitorAction>,
      );
    };
}