// Project persistence in localStorage, plus migrations from older data shapes.
import {
  makeId,
  indexKey,
  projectKey,
  loadProjectIndex,
} from './bibleUtils.jsx';

// ---------------------------------------------------------------------------
// Migration helpers (exported for testing)
// ---------------------------------------------------------------------------

export function migrateChunk(chunk) {
  if (chunk.observation !== undefined) {
    return {
      ...chunk,
      spilloverEndVerse: Number.isInteger(chunk.spilloverEndVerse) ? chunk.spilloverEndVerse : null,
      generalNotes: chunk.generalNotes ?? '',
      episodeNumber: chunk.episodeNumber ?? '',
      episodeTitle: chunk.episodeTitle ?? '',
      finalScript: chunk.finalScript ?? '',
      tags: chunk.tags ?? [],
    }; // already new format
  }
  return {
    ...chunk,
    observation: chunk.notes ?? '',
    interpretation: '',
    application: '',
    crossReferences: [],
    tags: [],
    spilloverEndVerse: null,
    generalNotes: '',
    episodeNumber: '',
    episodeTitle: '',
    finalScript: '',
    notes: undefined,
  };
}

export function migrateProject(raw) {
  if (!raw) return null;
  // Already new format
  if (Array.isArray(raw.chapters)) {
    return {
      ...raw,
      chapters: raw.chapters.map((ch) => ({
        ...ch,
        chunks: ch.chunks.map(migrateChunk),
      })),
    };
  }
  // Old flat format → wrap in chapters array
  const id = raw.id ?? makeId();
  return {
    id,
    title: raw.title ?? '',
    translation: raw.translation ?? 'BSB',
    lastEdited: raw.lastEdited ?? Date.now(),
    selectedChunkId: raw.selectedChunkId ?? null,
    chapters: [
      {
        book: raw.book ?? '',
        bookAbbrev: raw.bookAbbrev ?? '',
        chapter: raw.chapter ?? '1',
        verses: raw.verses ?? [],
        chunks: (raw.chunks ?? []).map(migrateChunk),
      },
    ],
  };
}

// ---------------------------------------------------------------------------
// Storage helpers
// ---------------------------------------------------------------------------

export function saveProjectToStorage(project) {
  // Honour an already-stamped lastEdited (e.g. from autosave) so localStorage
  // and the server always receive the identical timestamp.
  const updated = { ...project, lastEdited: project.lastEdited ?? Date.now() };
  window.localStorage.setItem(projectKey(updated.id), JSON.stringify(updated));
  const index = loadProjectIndex();
  const existing = index.findIndex((e) => e.id === updated.id);
  const tags = Array.from(
    new Set(
      (updated.chapters ?? [])
        .flatMap((ch) => ch.chunks ?? [])
        .flatMap((chunk) => chunk.tags ?? []),
    ),
  );
  const summary = {
    id: updated.id,
    title: updated.title,
    lastEdited: updated.lastEdited,
    chapterSummary: buildChapterSummary(updated),
    series: (updated.series ?? '').trim(),
    tags,
  };
  if (existing >= 0) {
    index[existing] = summary;
  } else {
    index.push(summary);
  }
  window.localStorage.setItem(indexKey(), JSON.stringify(index));
  return updated; // caller can use this exact object for the server PUT
}

export function deleteProjectFromStorage(id) {
  window.localStorage.removeItem(projectKey(id));
  const index = loadProjectIndex().filter((e) => e.id !== id);
  window.localStorage.setItem(indexKey(), JSON.stringify(index));
}

export function loadProjectById(id) {
  try {
    const raw = window.localStorage.getItem(projectKey(id));
    return raw ? migrateProject(JSON.parse(raw)) : null;
  } catch {
    return null;
  }
}

export function migrateOldStorageKeys() {
  const keys = Object.keys(window.localStorage);
  keys.forEach((key) => {
    if (!key.startsWith('bible-study-') || key.startsWith('bible-study-index') || key.startsWith('bible-study-project')) return;
    try {
      const raw = JSON.parse(window.localStorage.getItem(key));
      if (!raw || !raw.book) return;
      const migrated = migrateProject(raw);
      if (!migrated) return;
      saveProjectToStorage(migrated);
      window.localStorage.removeItem(key);
    } catch {
      // skip corrupt entries
    }
  });
}

export function buildChapterSummary(project) {
  if (!Array.isArray(project.chapters)) return '';
  return project.chapters
    .map((ch) => `${ch.book} ${ch.chapter}`)
    .join(', ');
}