import { Injectable } from '@angular/core';
import { Platform } from 'ionic-angular';
import { AppConf } from '../app-conf/app-conf';
import { SQLite } from '@ionic-native/sqlite';
import { DB_CONFIG } from '../../app/app.constant';
import { SQLitePorter } from '@ionic-native/sqlite-porter';
const win: any = window;  

@Injectable()
export class DbSvc {

  private dbConfig = new DB_CONFIG();
  
  
  constructor(private sqlite: SQLite, public appConf: AppConf, public platform: Platform,
    public sqlitePorter: SQLitePorter) {

  }

  private dbInstance = null;

  private SQLError = {
    'UNKNOWN_ERR': 0,
    'DATABASE_ERR': 1,
    'VERSION_ERR': 2,
    'TOO_LARGE_ERR': 3,
    'QUOTA_ERR': 4,
    'SYNTAX_ERR': 5,
    'CONSTRAINT_ERR': 6,
    'TIMEOUT_ERR': 7
  };


  public errorHandler(res) {
    let msg = "";
    switch (res.code) {
      case this.SQLError.DATABASE_ERR:
        msg = "Database Error";
        break;
      case this.SQLError.VERSION_ERR:
        msg = "Version Error";
        break;
      case this.SQLError.TOO_LARGE_ERR:
        msg = "Too Large Error";
        break;
      case this.SQLError.QUOTA_ERR:
        msg = "Quota Error";
        break;
      case this.SQLError.SYNTAX_ERR:
        msg = "Syntax Error";
        break;
      case this.SQLError.CONSTRAINT_ERR:
        msg = "Constraint Error";
        break;
      default:
        msg = "Unknown Error";
        break;
    }
    return msg;
  }

  init() {
    if (this.platform.is('cordova')) {
      this.platform.ready().then(() => {
        this.dbInstance = this.sqlite.create({
          name: this.appConf.getDBName() + ".db",
          location: 'default'
        });
      });
    } else {
      this.dbInstance = win.openDatabase(this.appConf.getDBName(), "1.0", "database", 1);  //default db name :- DriverAPP
    }

    let promArray = [];

    this.dbConfig.tables.forEach(tablesql => {
      let promise = new Promise((resolve, reject) => {
        this.query(tablesql).then((res) => {
          resolve(res);
        }, (err) => {
          reject(err);
        });
      });
      promArray.push(promise);
    });

    return Promise.all(promArray);
  };


  public fetchAll(result) {
    let output = [];
    for (let i = 0; i < result.rows.length; i++) {
      output.push(result.rows.item(i));
    }
    return output;
  };

  public fetch(result) {
    return result.rows.item(0);
  };

  public query(query, bindings?) {
    if (this.dbInstance == null) {
      this.init();
    }

    bindings = typeof bindings !== 'undefined' ? bindings : [];

    let promise = new Promise((resolve, reject) => {
      this.dbInstance.transaction((transaction) => {
        transaction.executeSql(query, bindings, (transaction, result) => {
          resolve(result);
        }, (transaction, error) => {
          error.Error = this.errorHandler(error);
          reject(error);
        });
      });
    });

    return promise;
  };


  public isDataExist(tableName, value) {
    let promise = new Promise((resolve, reject) => {
      if (value) {
        let selectsql = "SELECT " + tableName + "_uu FROM " + tableName + " WHERE " + tableName + "_uu = ?";
        this.query(selectsql, [value]).then((rs) => {
          if (rs['rows'].length > 0)
            resolve(true);
          else
            resolve(false);
        });
      } else {
        resolve(false);
      }
    });

    return promise;
  };


  public removeRecordByTableID(tableName, value) {
    if (value) {
      let selectsql = "Delete * from " + tableName + " WHERE " + tableName + "_uu = ?";
      return this.query(selectsql, [value]);
    }
  };

  public addTableRow(tableName, row, isServerPull) {
    let initUpdateTime = Date.now();
    let params = [],
      paramStr = [],
      paramKeys = [];
    let keys = Object.keys(row);

    keys.forEach(key => {
      if (key === "$$hashKey" || key.toLowerCase() === "app_updated" || key.toLowerCase() === "app_synced") { } else {
        params.push(row[key]);
        paramStr.push("?");
        paramKeys.push(key);
      }
    });

    let sql = "Insert into " + tableName + " (" + paramKeys.join(',') + ") Values (" + paramStr.join(',') + ")";
    let exec = this.query(sql, params);

    if (arguments.length === 3 && isServerPull === true) {
      sql = "Update " + tableName + " SET app_updated = " + initUpdateTime + ", app_synced = "
        + initUpdateTime + " where " + tableName.toLowerCase() + "_uu = ?";
      var UU = row[tableName.toLowerCase() + "_uu"];
      this.query(sql, [UU]);
    } else {
      // Generic Logic for set Record Updated Time 
      sql = "Update " + tableName + " Set app_updated = " + initUpdateTime + " where " + tableName.toLowerCase() + "_uu = ?";
      let UU = row[tableName.toLowerCase() + "_uu"];
      this.query(sql, [UU]);
    }
    return exec;
  };


  public addTableRowByColumn(tableName, columns, row) {
    let initUpdateTime = Date.now();
    let params = [],
      paramStr = [],
      paramKeys = [];
    let keys = Object.keys(row);

    keys.forEach(key => {
      if (key === "$$hashKey" || columns.indexOf(key) < 0 || key.toLowerCase() === "app_updated" || key.toLowerCase() === "app_synced") {
        // Skip to add 
      } else {
        params.push(row[key]);
        paramStr.push("?");
        paramKeys.push(key);
      }
    });

    let sql = "Insert into " + tableName + " (" + paramKeys.join(',') + ") Values (" + paramStr.join(',') + ")";
    let exec = this.query(sql, params);

    // Generic Logic for set Record Updated Time 
    sql = "Update " + tableName + " Set app_updated = " + initUpdateTime + " where " + tableName.toLowerCase() + "_uu = ?";
    let UU = row[tableName.toLowerCase() + "_uu"];
    this.query(sql, [UU]);

    return exec;
  };

  public updateTableRow(tableName, row) {
    let initUpdateTime = Date.now();
    let paramStr = [];
    let idColumn = tableName + "_uu";
    let param = [];
    let keys = Object.keys(row);

    keys.forEach(key => {
      if (key === "$$hashKey" || key.toLowerCase() === "app_updated" || key.toLowerCase() === "app_synced") { } else {
        paramStr.push(key + "= ? ");
        param.push(row[key]);
      }
    });

    param.push(row[idColumn]);

    let sql = "Update " + tableName + " set " + paramStr.join(',') + " WHERE " + idColumn + " = ? ";
    let exec = this.query(sql, param);

    // Generic Logic for set Record Updated Time 
    sql = "Update " + tableName + " Set app_updated = " + initUpdateTime + " where " + tableName.toLowerCase() + "_uu = ?";
    let UU = row[tableName.toLowerCase() + "_uu"];
    this.query(sql, [UU]);

    return exec;
  };

  public getCount(tableName, whereClause) {
    let sql = "SELECT Count(" + tableName + "_uu) FROM " + tableName;
    if (whereClause !== 'undefined' || whereClause != null)
      sql = sql + " WHERE " + whereClause;
    return this.query(sql, 'undefined');
  }


  //need to test working or not
  exportDBToFile() {
    let promise = new Promise((resolve, reject) => {
      if (!this.dbInstance)
        this.init();

      var successFn = function (sql, count) {
        resolve(sql);
        alert("Exported SQL contains " + count + " statements");
      };
      if (this.platform.is('android')) {
        this.sqlitePorter.exportDbToSql(this.dbInstance).then(successFn => {
          resolve(successFn); //TO DO task: return what? and what send as promises 
        }).catch(err => {
          reject(err);
        })
        // window.cordova.plugins.sqlitePorter.exportDbToSql(this.dbInstance, {
        //   successFn: successFn
        // });
      }
    });
    return promise;
  }


}