// Ported from filius-ipad (GPLv2/GPLv3):
//   ios/FiliusPad/TopologyEditor/Persistence/TopologyFLSArchive.swift
//     importFiliusArchiveDocument, exportFiliusArchiveWithReport (the archive part)
// Java counterpart: filius.rahmenprogramm.SzenarioVerwaltung (its save and load methods).
//
// A .fls holds the project in `projekt/konfiguration.xml` and the list of the
// user's own Java applications in `projekt/anwendungen/EigeneAnwendungen.txt`
// (plus their sources and classes). Everything besides the configuration is
// carried through unchanged: this port cannot run custom Java applications,
// but it must not destroy them either.

import { canonicalEntryKey, FlsArchiveError, readZipEntries, writeZipEntries } from './zip.js';

export const CONFIGURATION_ENTRY_PATH = 'projekt/konfiguration.xml';
export const APPLICATIONS_ENTRY_PATH = 'projekt/anwendungen/EigeneAnwendungen.txt';

export interface FlsArchiveContents {
  /** `projekt/konfiguration.xml`, as bytes. */
  readonly configurationXml: Uint8Array;
  /** Every other entry, carried through to the next save. */
  readonly supplementalEntries: ReadonlyMap<string, Uint8Array>;
  /** All entry paths of the archive, sorted. */
  readonly entryPaths: readonly string[];
}

/** Opens a .fls: checks the archive and separates the configuration from the rest. */
export function readFlsArchive(archive: Uint8Array): FlsArchiveContents {
  const entries = readZipEntries(archive);
  const configurationXml = entries.get(CONFIGURATION_ENTRY_PATH);
  if (configurationXml === undefined) {
    throw new FlsArchiveError('missingConfiguration', CONFIGURATION_ENTRY_PATH, 'The required configuration entry is missing.');
  }
  const supplementalEntries = new Map(entries);
  supplementalEntries.delete(CONFIGURATION_ENTRY_PATH);
  return {
    configurationXml,
    supplementalEntries,
    entryPaths: [...entries.keys()].sort(),
  };
}

/**
 * Writes a .fls from a configuration and the entries carried along. A
 * carried entry may not pose as one of the two FILIUS entries under another
 * spelling (`PROJEKT/Konfiguration.xml`); the application list is added
 * empty when missing, as Java always writes it.
 */
export function writeFlsArchive(
  configurationXml: Uint8Array,
  supplementalEntries: ReadonlyMap<string, Uint8Array> = new Map(),
): Uint8Array {
  const criticalConfigurationKey = canonicalEntryKey(CONFIGURATION_ENTRY_PATH);
  const criticalApplicationsKey = canonicalEntryKey(APPLICATIONS_ENTRY_PATH);
  for (const path of supplementalEntries.keys()) {
    const key = canonicalEntryKey(path);
    const isExactCriticalPath = path === CONFIGURATION_ENTRY_PATH || path === APPLICATIONS_ENTRY_PATH;
    if ((key === criticalConfigurationKey || key === criticalApplicationsKey) && !isExactCriticalPath) {
      throw new FlsArchiveError('duplicateEntry', path, 'Supplemental entry conflicts with a critical FILIUS archive path.');
    }
  }
  const entries = new Map(supplementalEntries);
  if (!entries.has(APPLICATIONS_ENTRY_PATH)) entries.set(APPLICATIONS_ENTRY_PATH, new Uint8Array());
  entries.set(CONFIGURATION_ENTRY_PATH, configurationXml);
  return writeZipEntries(entries);
}