/* jslint node: true */
'use strict';

//  ENiGMA½
const stringFormat = require('./string_format.js');
const FileEntry = require('./file_entry.js');
const FileArea = require('./file_base_area.js');
const Config = require('./config.js').get;
const { Errors } = require('./enig_error.js');
const { splitTextAtTerms, isAnsi } = require('./string_util.js');
const AnsiPrep = require('./ansi_prep.js');
const Log = require('./logger.js').log;

//  deps
const _ = require('lodash');
const async = require('async');
const fs = require('graceful-fs');
const paths = require('path');
const iconv = require('iconv-lite');
const moment = require('moment');

exports.exportFileList = exportFileList;
exports.updateFileBaseDescFilesScheduledEvent = updateFileBaseDescFilesScheduledEvent;

function exportFileList(filterCriteria, options, cb) {
    options.templateEncoding = options.templateEncoding || 'utf8';
    options.entryTemplate =
        options.entryTemplate || 'descript_ion_export_entry_template.asc';
    options.tsFormat = options.tsFormat || 'YYYY-MM-DD';
    options.descWidth = options.descWidth || 45; //  FILE_ID.DIZ spec
    options.escapeDesc = _.get(options, 'escapeDesc', false); //  escape \r and \n in desc?

    if (true === options.escapeDesc) {
        options.escapeDesc = '\\n';
    }

    const state = {
        total: 0,
        current: 0,
        step: 'preparing',
        status: 'Preparing',
    };

    const updateProgress = _.isFunction(options.progress)
        ? progCb => {
              return options.progress(state, progCb);
          }
        : progCb => {
              return progCb(null);
          };
    async.waterfall(
        [
            function readTemplateFiles(callback) {
                updateProgress(err => {
                    if (err) {
                        return callback(err);
                    }

                    const templateFiles = [
                        { name: options.headerTemplate, req: false },
                        { name: options.entryTemplate, req: true },
                    ];

                    const config = Config();
                    async.map(
                        templateFiles,
                        (template, nextTemplate) => {
                            if (!template.name && !template.req) {
                                return nextTemplate(null, Buffer.from([]));
                            }

                            template.name = paths.isAbsolute(template.name)
                                ? template.name
                                : paths.join(config.paths.misc, template.name);
                            fs.readFile(template.name, (err, data) => {
                                return nextTemplate(err, data);
                            });
                        },
                        (err, templates) => {
                            if (err) {
                                return callback(Errors.General(err.message));
                            }

                            //  decode + ensure DOS style CRLF
                            templates = templates.map(tmp =>
                                iconv
                                    .decode(tmp, options.templateEncoding)
                                    .replace(/\r?\n/g, '\r\n')
                            );

                            //  Look for the first {fileDesc} (if any) in 'entry' template & find indentation requirements
                            let descIndent = 0;
                            if (!options.escapeDesc) {
                                splitTextAtTerms(templates[1]).some(line => {
                                    const pos = line.indexOf('{fileDesc}');
                                    if (pos > -1) {
                                        descIndent = pos;
                                        return true; //  found it!
                                    }
                                    return false; //  keep looking
                                });
                            }

                            return callback(null, templates[0], templates[1], descIndent);
                        }
                    );
                });
            },
            function findFiles(headerTemplate, entryTemplate, descIndent, callback) {
                state.step = 'gathering';
                state.status = 'Gathering files for supplied criteria';
                updateProgress(err => {
                    if (err) {
                        return callback(err);
                    }

                    FileEntry.findFiles(filterCriteria, (err, fileIds) => {
                        if (0 === fileIds.length) {
                            return callback(
                                Errors.General('No results for criteria', 'NORESULTS')
                            );
                        }

                        return callback(
                            err,
                            headerTemplate,
                            entryTemplate,
                            descIndent,
                            fileIds
                        );
                    });
                });
            },
            function buildListEntries(
                headerTemplate,
                entryTemplate,
                descIndent,
                fileIds,
                callback
            ) {
                const formatObj = {
                    totalFileCount: fileIds.length,
                };

                let current = 0;
                let listBody = '';
                const totals = { fileCount: fileIds.length, bytes: 0 };
                state.total = fileIds.length;

                state.step = 'file';

                async.eachSeries(
                    fileIds,
                    (fileId, nextFileId) => {
                        const fileInfo = new FileEntry();
                        current += 1;

                        fileInfo.load(fileId, err => {
                            if (err) {
                                return nextFileId(null); //  failed, but try the next
                            }

                            totals.bytes += fileInfo.meta.byte_size;

                            const appendFileInfo = () => {
                                if (options.escapeDesc) {
                                    formatObj.fileDesc = formatObj.fileDesc.replace(
                                        /\r?\n/g,
                                        options.escapeDesc
                                    );
                                }

                                if (options.maxDescLen) {
                                    formatObj.fileDesc = formatObj.fileDesc.slice(
                                        0,
                                        options.maxDescLen
                                    );
                                }

                                listBody += stringFormat(entryTemplate, formatObj);

                                state.current = current;
                                state.status = `Processing ${fileInfo.fileName}`;
                                state.fileInfo = formatObj;

                                updateProgress(err => {
                                    return nextFileId(err);
                                });
                            };

                            const area = FileArea.getFileAreaByTag(fileInfo.areaTag);

                            formatObj.fileId = fileId;
                            formatObj.areaName = _.get(area, 'name') || 'N/A';
                            formatObj.areaDesc = _.get(area, 'desc') || 'N/A';
                            formatObj.userRating = fileInfo.userRating || 0;
                            formatObj.fileName = fileInfo.fileName;
                            formatObj.fileSize = fileInfo.meta.byte_size;
                            formatObj.fileDesc = fileInfo.desc || '';
                            formatObj.fileDescShort = formatObj.fileDesc.slice(
                                0,
                                options.descWidth
                            );
                            formatObj.fileSha256 = fileInfo.fileSha256;
                            formatObj.fileCrc32 = fileInfo.meta.file_crc32;
                            formatObj.fileMd5 = fileInfo.meta.file_md5;
                            formatObj.fileSha1 = fileInfo.meta.file_sha1;
                            formatObj.uploadBy =
                                fileInfo.meta.upload_by_username || 'N/A';
                            formatObj.fileUploadTs = moment(
                                fileInfo.uploadTimestamp
                            ).format(options.tsFormat);
                            formatObj.fileHashTags =
                                fileInfo.hashTags.size > 0
                                    ? Array.from(fileInfo.hashTags).join(', ')
                                    : 'N/A';
                            formatObj.currentFile = current;
                            formatObj.progress = Math.floor(
                                (current / fileIds.length) * 100
                            );

                            if (isAnsi(fileInfo.desc)) {
                                AnsiPrep(
                                    fileInfo.desc,
                                    {
                                        cols: Math.min(
                                            options.descWidth,
                                            79 - descIndent
                                        ),
                                        forceLineTerm: true, //  ensure each line is term'd
                                        asciiMode: true, //  export to ASCII
                                        fillLines: false, //  don't fill up to |cols|
                                        indent: descIndent,
                                    },
                                    (err, desc) => {
                                        if (desc) {
                                            formatObj.fileDesc = desc;
                                        }
                                        return appendFileInfo();
                                    }
                                );
                            } else {
                                const indentSpc =
                                    descIndent > 0 ? ' '.repeat(descIndent) : '';
                                formatObj.fileDesc =
                                    splitTextAtTerms(formatObj.fileDesc).join(
                                        `\r\n${indentSpc}`
                                    ) + '\r\n';
                                return appendFileInfo();
                            }
                        });
                    },
                    err => {
                        return callback(err, listBody, headerTemplate, totals);
                    }
                );
            },
            function buildHeader(listBody, headerTemplate, totals, callback) {
                //  header is built last such that we can have totals/etc.

                let filterAreaName;
                let filterAreaDesc;
                if (filterCriteria.areaTag) {
                    const area = FileArea.getFileAreaByTag(filterCriteria.areaTag);
                    filterAreaName = _.get(area, 'name') || 'N/A';
                    filterAreaDesc = _.get(area, 'desc') || 'N/A';
                } else {
                    filterAreaName = '-ALL-';
                    filterAreaDesc = 'All areas';
                }

                const headerFormatObj = {
                    nowTs: moment().format(options.tsFormat),
                    boardName: Config().general.boardName,
                    totalFileCount: totals.fileCount,
                    totalFileSize: totals.bytes,
                    filterAreaTag: filterCriteria.areaTag || '-ALL-',
                    filterAreaName: filterAreaName,
                    filterAreaDesc: filterAreaDesc,
                    filterTerms: filterCriteria.terms || '(none)',
                    filterHashTags: filterCriteria.tags || '(none)',
                };

                listBody = stringFormat(headerTemplate, headerFormatObj) + listBody;
                return callback(null, listBody);
            },
            function done(listBody, callback) {
                delete state.fileInfo;
                state.step = 'finished';
                state.status = 'Finished processing';
                updateProgress(() => {
                    return callback(null, listBody);
                });
            },
        ],
        (err, listBody) => {
            return cb(err, listBody);
        }
    );
}

function updateFileBaseDescFilesScheduledEvent(args, cb) {
    //
    //  For each area, loop over storage locations and build
    //  DESCRIPT.ION file to store in the same directory.
    //
    //  Standard-ish 4DOS spec is as such:
    //  * Entry: <QUOTED_LFN> <DESC>[0x04<AppData>]\r\n
    //  * Multi line descriptions are stored with *escaped* \r\n pairs
    //  * Default template uses 0x2c for <AppData> as per https://stackoverflow.com/questions/1810398/descript-ion-file-spec
    //
    const entryTemplate = args[0];
    const headerTemplate = args[1];

    const areas = FileArea.getAvailableFileAreas(null, { skipAcsCheck: true });
    async.each(
        areas,
        (area, nextArea) => {
            const storageLocations = FileArea.getAreaStorageLocations(area);

            async.each(
                storageLocations,
                (storageLoc, nextStorageLoc) => {
                    const filterCriteria = {
                        areaTag: area.areaTag,
                        storageTag: storageLoc.storageTag,
                    };

                    const exportOpts = {
                        headerTemplate: headerTemplate,
                        entryTemplate: entryTemplate,
                        escapeDesc: true, //  escape CRLF's
                        maxDescLen: 4096, //  DESCRIPT.ION: "The line length limit is 4096 bytes"
                    };

                    exportFileList(filterCriteria, exportOpts, (err, listBody) => {
                        const descIonPath = paths.join(storageLoc.dir, 'DESCRIPT.ION');
                        fs.writeFile(
                            descIonPath,
                            iconv.encode(listBody, 'cp437'),
                            err => {
                                if (err) {
                                    Log.warn(
                                        { error: err.message, path: descIonPath },
                                        'Failed (re)creating DESCRIPT.ION'
                                    );
                                } else {
                                    Log.debug(
                                        { path: descIonPath },
                                        '(Re)generated DESCRIPT.ION'
                                    );
                                }
                                return nextStorageLoc(null);
                            }
                        );
                    });
                },
                () => {
                    return nextArea(null);
                }
            );
        },
        () => {
            return cb(null);
        }
    );
}