"use strict";

var url = require( "url" );
var path = require( "path" );
var inline = require( "./util" );

module.exports = function( options, callback )
{
    var settings = Object.assign( {}, inline.defaults, options );

    var replaceUrl = function( callback )
    {
        var args = this;

        if( inline.isBase64Path( args.src ) )
        {
            return callback( null ); // Skip
        }

        inline.getFileReplacement( args.src, settings, function( err, datauriContent )
        {
            if( err )
            {
                return inline.handleReplaceErr( err, args.src, settings.strict, callback );
            }
            if( typeof( args.limit ) === "number" && datauriContent.length > args.limit * 1000 )
            {
                return callback( null ); // Skip
            }

            var css = "url(\"" + datauriContent + "\")";
            var re = new RegExp( "url\\(\\s?[\"']?(" + inline.escapeSpecialChars( args.src ) + ")[\"']?\\s?\\)", "g" );
            result = result.replace( re, () => css );

            return callback( null );
        } );
    };

    var rebase = function( src )
    {
        var css = "url(\"" + ( inline.isRemotePath( src ) || inline.isRemotePath( settings.rebaseRelativeTo ) ? url.resolve( settings.rebaseRelativeTo, src ) : path.join( settings.rebaseRelativeTo, src ).replace( /\\/g, "/" ) ) + "\")";
        var re = new RegExp( "url\\(\\s?[\"']?(" + inline.escapeSpecialChars( src ) + ")[\"']?\\s?\\)", "g" );
        result = result.replace( re, () => css );
    };

    var result = settings.fileContent;
    var tasks = [];
    var found = null;

    var urlRegex = /url\(\s?["']?([^)'"]+)["']?\s?\).*/i;
    var index = 0;

    if( settings.rebaseRelativeTo )
    {
        var matches = {};
        var src;

        while( ( found = urlRegex.exec( result.substring( index ) ) ) !== null )
        {
            src = found[ 1 ];
            matches[ src ] = true;
            index = found.index + index + 1;
        }

        for( src in matches )
        {
            if( !inline.isRemotePath( src ) && !inline.isBase64Path( src ) )
            {
                rebase( src );
            }
        }
    }

    var inlineAttributeCommentRegex = new RegExp( "\\/\\*\\s?" + settings.inlineAttribute + "\\s?\\*\\/", "i" );
    var inlineAttributeIgnoreCommentRegex = new RegExp( "\\/\\*\\s?" + settings.inlineAttribute + "-ignore\\s?\\*\\/", "i" );

    index = 0;
    while( ( found = urlRegex.exec( result.substring( index ) ) ) !== null )
    {
        if( !inlineAttributeIgnoreCommentRegex.test( found[ 0 ] ) &&
            ( settings.images || inlineAttributeCommentRegex.test( found[ 0 ] ) ) )
        {
            tasks.push( replaceUrl.bind(
            {
                src: found[ 1 ],
                limit: settings.images
            } ) );
        }
        index = found.index + index + 1;
    }

    var promises = tasks.map( function( fn )
    {
        return new Promise( function( resolve, reject )
        {
            fn( function( error )
            {
                if ( error ) {
                    reject ( error );
                } else {
                    resolve();
                }
            } );
        } );
    } );

    Promise.all( promises )
        .then( function()
        {
            callback( null, result );
        }, function( error )
        {
            callback( error, result );
        } );
};