import { promises as fs } from "fs";
import * as path from "path";

import { RJLog } from "../log/RJLog";
import { PathReference } from "./PathReference";
import { DOMShim } from "../DOMShim";
import { DateMath } from "../../browser/date/DateMath";

export class Files
{
  static parentPath( filePath:string )
  {
    return path.dirname( filePath );
  }

  static async forAllIn( filePath:string, filter:(p:PathReference)=>Promise<boolean> = null, action:(p:PathReference)=>Promise<void> = null ):Promise<PathReference[]>
  {
    let files = await fs.readdir( filePath );

    let root = new PathReference( filePath );
    let pathReferences = files.map( f => root.createRelative( f ) );

    if ( filter )
    { 
      let filteredPaths = [];

      for ( let p of pathReferences )
      {
        if ( await filter( p ) )
        {
          filteredPaths.push( p );
        }
      }

      pathReferences = filteredPaths;

    };

    for ( let p of pathReferences )
    {
      let isDirectory = await p.isDirectory();

      if ( isDirectory )
      {
        await this.forAllIn( p.absolutePath, filter, action );
      }
    }

    if ( action )
    {
      for ( let p of pathReferences )
      {
        await action( p );
      }
    }

    return Promise.resolve( pathReferences );
  }

  static async forDirectChildrenIn( filePath:string, filter:(p:PathReference)=>Promise<boolean> = null, action:(p:PathReference)=>Promise<void> = null ):Promise<PathReference[]>
  {
    let files = await fs.readdir( filePath );

    let root = new PathReference( filePath );
    let pathReferences = files.map( f => root.createRelative( f ) );

    if ( filter )
    { 
      let filteredPaths = [];

      for ( let p of pathReferences )
      {
        if ( await filter( p ) )
        {
          filteredPaths.push( p );
        }
      }

      pathReferences = filteredPaths;

    };

    if ( action )
    {
      for ( let p of pathReferences )
      {
        await action( p );
      }
    }

    return Promise.resolve( pathReferences );

  }
  
  static joinPaths( pathFragments:string[] )
  {
    return path.join.apply( path, pathFragments );
  }

  static async existsIn( directoryPath:string, fileName:string ):Promise<boolean>
  {
    let combinedPath = Files.joinPaths( [ directoryPath, fileName ] );
    let result = await Files.exists( combinedPath );

    return Promise.resolve( result );
  }

  static async getStatistics( filePath:string )
  {
    return fs.stat( filePath );
  }

  static async getModificationDate( filePath:string ):Promise<Date>
  {
    let stats = await this.getStatistics( filePath );

    if ( ! stats )
    {
      return Promise.resolve( null );
    }

    return new Date( stats.mtimeMs );
  }

  static async isNewerThan( filePath:string, date:Date ):Promise<boolean>
  {
    let mDate = await this.getModificationDate( filePath );

    return Promise.resolve( DateMath.isAfter( mDate, date ) );
  } 

  static async isDirectory( filePath:string ):Promise<boolean>
  {
    try
    {
      let stats = await fs.stat( filePath );  
      
      return Promise.resolve( stats !== null && stats !== undefined && stats.isDirectory() );
    }
    catch( e )
    {
      return false;
    }

    return Promise.resolve( false );    
  }

  static async isFile( filePath:string ):Promise<boolean>
  {
    try
    {
      let stats = await fs.stat( filePath );  
      
      return Promise.resolve( stats !== null && stats !== undefined && stats.isFile() );
    }
    catch( e )
    {
      return false;
    }

    return Promise.resolve( false );    
  }

  static async isSymbolicLink( filePath:string ):Promise<boolean>
  {
    try
    {
      let stats = await fs.stat( filePath );  
      
      return Promise.resolve( stats !== null && stats !== undefined && stats.isSymbolicLink() );
    }
    catch( e )
    {
      return false;
    }

    return Promise.resolve( false );    
  }

  static async exists( filePath:string ):Promise<boolean>
  {
    try
    {
      let stats = await fs.stat( filePath );  
      
      return Promise.resolve( stats !== null && stats !== undefined );
    }
    catch( e )
    {
      return false;
    }

    return Promise.resolve( false );    
  }

  static async ensureDirectoryExists( path:string ):Promise<void>
  {
    let exists = await Files.exists( path );

    if ( exists )
    {
      return Promise.resolve();
    }

    await fs.mkdir( path, { recursive: true } );

    return Promise.resolve();
  }

  static async ensureParentDirectoryExists( filePath:string ):Promise<void>
  {
    let path = Files.parentPath( filePath );
    let exists = await Files.exists( path );

    if ( exists )
    {
      return Promise.resolve();
    }

    await fs.mkdir( path );

    return Promise.resolve();
  }

  static async deleteFile( filePath:string ):Promise<boolean>
  {
    try
    {
      await fs.unlink( filePath );
    }
    catch( e ) 
    {
      return Promise.resolve( false );
    } 

    return Promise.resolve( true );
    
  }

  
  static async loadUTF8( filePath:string ):Promise<string>
  {
    try
    {
      let data = await fs.readFile( filePath );
      let stringData = data.toString();
      return Promise.resolve( stringData );
    }
    catch ( exception )
    { 
      RJLog.log( exception );
    }
    
    return Promise.resolve( null );

  }

  

  static async moveFile( oldPath:string, newPath:string )
  {
    try
    {
      await fs.rename( oldPath, newPath );
    }
    catch ( e )
    {
      await fs.copyFile( oldPath, newPath );
      await fs.unlink( oldPath );
    }
  }

  static async loadJSON<T>( filePath:string ):Promise<T>
  {
    let text = await Files.loadUTF8( filePath );

    if ( text === null )
    {
      return Promise.resolve( null );
    }
    
    try
    {
      let jsonObject = JSON.parse( text );

      return Promise.resolve( jsonObject as T );
    }
    catch ( exception )
    {
      RJLog.log( exception );
    }

    return Promise.resolve( null );
  }

  static async saveUTF8( filePath:string, text:string ):Promise<boolean>
  {
    try
    {
      await fs.writeFile( filePath, text );
      return Promise.resolve( true );
    }
    catch ( exception )
    { 
      RJLog.log( exception );
    }
    
    return Promise.resolve( false );

  }

  static async saveJSON<T>( filePath:string, data:T ):Promise<boolean>
  {
    try
    {
      let jsonData = JSON.stringify( data );
      let result = await Files.saveUTF8( filePath, jsonData );

      return Promise.resolve( result );
    }
    catch( e ) 
    {
      RJLog.log( e );
    }

    
    return Promise.resolve( false );
  }

  static async saveXML( filePath:string, rootElement:Element ):Promise<void>
  {
    let domShim = DOMShim.$;  

    let nodeName = rootElement.nodeName;
    let xmlHeader = `<?xml version="1.0" encoding="UTF-8" standalone="no"?>` + "\n";
    let serializedXML = `${xmlHeader}<${nodeName}>${rootElement.innerHTML}</${nodeName}>` ;

    //RJLog.log( rootElement, serializedXML );

    await Files.saveUTF8( filePath, serializedXML );

    return Promise.resolve();
  }

  static async loadXML( filePath:string ):Promise<Document>
  {
    let domShim = DOMShim.$; 

    let stringData = await Files.loadUTF8( filePath );
    let parser = new DOMParser();
    let xmlDoc = parser.parseFromString( stringData, "text/xml" );
    return xmlDoc;
  }

  static async loadHTML( filePath:string ):Promise<Document>
  {
    let domShim = DOMShim.$; 

    let stringData = await Files.loadUTF8( filePath );
    let parser = new DOMParser();
    let xmlDoc = parser.parseFromString( stringData, "text/html" );
    return xmlDoc;
  }

  static async saveHTML( filePath:string, rootElement:Element ):Promise<void>
  {
    let domShim = DOMShim.$;  

    await Files.saveUTF8( filePath, rootElement.outerHTML );

    return Promise.resolve();
  }
}