import shortid from 'shortid';
import * as actions from './actions';
import { now } from '../modules/dates';

const defaultQueryEditor = {
  id: shortid.generate(),
  title: 'Untitled Query',
  sql: 'SELECT *\nFROM\nWHERE',
  latestQueryId: null,
  autorun: false,
  dbId: null,
};

// TODO(bkyryliuk): document the object schemas
export const initialState = {
  alerts: [],
  queries: {},
  databases: {},
  queryEditors: [defaultQueryEditor],
  tabHistory: [defaultQueryEditor.id],
  tables: [],
  workspaceQueries: [],
  queriesLastUpdate: 0,
};

function addToObject(state, arrKey, obj) {
  const newObject = Object.assign({}, state[arrKey]);
  const copiedObject = Object.assign({}, obj);

  if (!copiedObject.id) {
    copiedObject.id = shortid.generate();
  }
  newObject[copiedObject.id] = copiedObject;
  return Object.assign({}, state, { [arrKey]: newObject });
}

function alterInObject(state, arrKey, obj, alterations) {
  const newObject = Object.assign({}, state[arrKey]);
  newObject[obj.id] = (Object.assign({}, newObject[obj.id], alterations));
  return Object.assign({}, state, { [arrKey]: newObject });
}

function alterInArr(state, arrKey, obj, alterations) {
  // Finds an item in an array in the state and replaces it with a
  // new object with an altered property
  const idKey = 'id';
  const newArr = [];
  state[arrKey].forEach((arrItem) => {
    if (obj[idKey] === arrItem[idKey]) {
      newArr.push(Object.assign({}, arrItem, alterations));
    } else {
      newArr.push(arrItem);
    }
  });
  return Object.assign({}, state, { [arrKey]: newArr });
}

function removeFromArr(state, arrKey, obj, idKey = 'id') {
  const newArr = [];
  state[arrKey].forEach((arrItem) => {
    if (!(obj[idKey] === arrItem[idKey])) {
      newArr.push(arrItem);
    }
  });
  return Object.assign({}, state, { [arrKey]: newArr });
}

function addToArr(state, arrKey, obj) {
  const newObj = Object.assign({}, obj);
  if (!newObj.id) {
    newObj.id = shortid.generate();
  }
  const newState = {};
  newState[arrKey] = [...state[arrKey], newObj];
  return Object.assign({}, state, newState);
}

export const sqlLabReducer = function (state, action) {
  const actionHandlers = {
    [actions.ADD_QUERY_EDITOR]() {
      const tabHistory = state.tabHistory.slice();
      tabHistory.push(action.queryEditor.id);
      const newState = Object.assign({}, state, { tabHistory });
      return addToArr(newState, 'queryEditors', action.queryEditor);
    },
    [actions.REMOVE_QUERY_EDITOR]() {
      let newState = removeFromArr(state, 'queryEditors', action.queryEditor);
      // List of remaining queryEditor ids
      const qeIds = newState.queryEditors.map((qe) => qe.id);
      let th = state.tabHistory.slice();
      th = th.filter((id) => qeIds.includes(id));
      newState = Object.assign({}, newState, { tabHistory: th });
      return newState;
    },
    [actions.REMOVE_QUERY]() {
      const newQueries = Object.assign({}, state.queries);
      delete newQueries[action.query.id];
      return Object.assign({}, state, { queries: newQueries });
    },
    [actions.RESET_STATE]() {
      return Object.assign({}, initialState);
    },
    [actions.ADD_TABLE]() {
      return addToArr(state, 'tables', action.table);
    },
    [actions.EXPAND_TABLE]() {
      return alterInArr(state, 'tables', action.table, { expanded: true });
    },
    [actions.COLLAPSE_TABLE]() {
      return alterInArr(state, 'tables', action.table, { expanded: false });
    },
    [actions.REMOVE_TABLE]() {
      return removeFromArr(state, 'tables', action.table);
    },
    [actions.START_QUERY]() {
      const newState = addToObject(state, 'queries', action.query);
      const sqlEditor = { id: action.query.sqlEditorId };
      return alterInArr(newState, 'queryEditors', sqlEditor, { latestQueryId: action.query.id });
    },
    [actions.STOP_QUERY]() {
      return alterInObject(state, 'queries', action.query, { state: 'stopped' });
    },
    [actions.QUERY_SUCCESS]() {
      const alts = {
        state: 'success',
        results: action.results,
        rows: action.results.data.length,
        progress: 100,
        endDttm: now(),
      };
      return alterInObject(state, 'queries', action.query, alts);
    },
    [actions.QUERY_FAILED]() {
      const alts = { state: 'failed', msg: action.msg, endDttm: now() };
      return alterInObject(state, 'queries', action.query, alts);
    },
    [actions.SET_ACTIVE_QUERY_EDITOR]() {
      const qeIds = state.queryEditors.map((qe) => qe.id);
      if (qeIds.includes(action.queryEditor.id)) {
        const tabHistory = state.tabHistory.slice();
        tabHistory.push(action.queryEditor.id);
        return Object.assign({}, state, { tabHistory });
      }
      return state;
    },
    [actions.QUERY_EDITOR_SETDB]() {
      return alterInArr(state, 'queryEditors', action.queryEditor, { dbId: action.dbId });
    },
    [actions.QUERY_EDITOR_SET_SCHEMA]() {
      return alterInArr(state, 'queryEditors', action.queryEditor, { schema: action.schema });
    },
    [actions.QUERY_EDITOR_SET_TITLE]() {
      return alterInArr(state, 'queryEditors', action.queryEditor, { title: action.title });
    },
    [actions.QUERY_EDITOR_SET_SQL]() {
      return alterInArr(state, 'queryEditors', action.queryEditor, { sql: action.sql });
    },
    [actions.QUERY_EDITOR_SET_AUTORUN]() {
      return alterInArr(state, 'queryEditors', action.queryEditor, { autorun: action.autorun });
    },
    [actions.ADD_WORKSPACE_QUERY]() {
      return addToArr(state, 'workspaceQueries', action.query);
    },
    [actions.REMOVE_WORKSPACE_QUERY]() {
      return removeFromArr(state, 'workspaceQueries', action.query);
    },
    [actions.ADD_ALERT]() {
      return addToArr(state, 'alerts', action.alert);
    },
    [actions.SET_DATABASES]() {
      const databases = {};
      action.databases.forEach((db) => {
        databases[db.id] = db;
      });
      return Object.assign({}, state, { databases });
    },
    [actions.REMOVE_ALERT]() {
      return removeFromArr(state, 'alerts', action.alert);
    },
    [actions.REFRESH_QUERIES]() {
      const newQueries = Object.assign({}, state.queries);
      // Fetch the updates to the queries present in the store.
      for (const queryId in state.queries) {
        newQueries[queryId] = Object.assign(newQueries[queryId], action.alteredQueries[queryId]);
      }
      const queriesLastUpdate = now();
      return Object.assign({}, state, { queries: newQueries, queriesLastUpdate });
    },
  };
  if (action.type in actionHandlers) {
    return actionHandlers[action.type]();
  }
  return state;
};