'use strict';

const Promise = require("bluebird");
const memoizee = require("memoizee");
const debug = require("debug")("iso9660:object:directory");

const parseDirectoryRecord = require("../parse/directory-record");

module.exports = function(image) {
    const createFile = require("./file")(image);

    return function createDirectory(directoryRecord, parent) {
        debug(`Creating new directory object for ${directoryRecord.identifier.filename}`);

        return {
            type: "directory",
            filename: directoryRecord.identifier.filename,
            version: directoryRecord.identifier.version,
            parent: parent,
            recordingDate: directoryRecord.recordingDate,

            getChildren: memoizee(function getChildren() {
                return Promise.try(() => {
                    function getDirectoryContents() {
                        return Promise.try(() => {
                            return image.getSectorOffset(directoryRecord.extentLocation);
                        }).then((sectorOffset) => {
                            return image.readRange(sectorOffset, sectorOffset + directoryRecord.extentSize - 1);
                        });
                    }

                    return Promise.all([
                        image.getPrimaryVolumeDescriptor(),
                        getDirectoryContents()
                    ]);
                }).spread((primaryVolumeDescriptor, directoryContents) => {
                    const roundToNextSector = require("../round-to-next-sector")(primaryVolumeDescriptor.data.sectorSize);

                    let pos = 0;
                    let records = [];

                    while (pos < directoryContents.length) {
                        let recordLength = directoryContents.readUInt8(pos);

                        if (recordLength === 0) {
                            /* We ran out of records for this sector, skip to the next. */
                            pos = roundToNextSector(pos);
                        } else {
                            let directoryRecord = parseDirectoryRecord(directoryContents.slice(pos, pos + recordLength));
                            records.push(directoryRecord);
                            pos += recordLength;
                        }
                    }

                    return records.slice(2).map((record) => {
                        if (record.fileFlags.directory) {
                            debug(`Found directory: ${record.identifier.filename}`);

                            return createDirectory(record, this);
                        } else {
                            debug(`Found file: ${record.identifier.filename}`);

                            return createFile(record, this);
                        }
                    });
                });
            }),
            getTree: function getTree() {
                return Promise.try(() => {
                    return this.getChildren();
                }).map((child) => {
                    if (child.type === "directory") {
                        return Promise.try(() => {
                            return child.getTree();
                        }).then((tree) => {
                            return Object.assign({
                                children: tree
                            }, child);
                        });
                    } else {
                        return child;
                    }
                });
            }
        }
    }
}