import fs from 'fs'
import path from 'path'
import type { Library } from '@/types'
import { getDb } from './db'
import { resolveLibraryRoot } from './libraries'
import { parseMovieNfo } from './nfo'

/**
 * Import NFO metadata for Movie items in a library.
 * - Reads .nfo file matching each movie file
 * - If importMetadataOnly=false: skip items that already have metadata (title/year/plot/genres)
 * - If importMetadataOnly=true: update all items regardless of existing metadata
 */
export async function importMovieMetadata(
  library: Library,
  importMetadataOnly: boolean = false
): Promise<{ imported: number; skipped: number }> {
  const db = getDb()
  const libraryRoot = resolveLibraryRoot(library)

  let imported = 0
  let skipped = 0

  // Get all movies in the library
  const movies = db
    .prepare(
      `SELECT item_key, file_path, title, year, plot, genres FROM media_items
       WHERE library_id = ? AND item_type = 'movie' AND file_path IS NOT NULL`
    )
    .all(library.id) as Array<{ item_key: string; file_path: string; title: string | null; year: number | null; plot: string | null; genres: string | null }>

  const updateItem = db.prepare(`
    UPDATE media_items SET title = @title, year = @year, plot = @plot, genres = @genres
    WHERE item_key = @item_key
  `)

  const BATCH_SIZE = 50
  for (let i = 0; i < movies.length; i += BATCH_SIZE) {
    const batch = movies.slice(i, i + BATCH_SIZE)

    db.transaction(() => {
      for (const item of batch) {
        // Check if we should skip this item
        if (!importMetadataOnly && hasMetadata(item)) {
          skipped++
          continue
        }

        const videoPath = path.join(libraryRoot, item.file_path)
        const dir = path.dirname(videoPath)
        const baseNameWithoutExt = path.basename(videoPath, path.extname(videoPath))
        const nfoPath = path.join(dir, `${baseNameWithoutExt}.nfo`)

        try {
          if (fs.existsSync(nfoPath)) {
            const nfoData = parseMovieNfo(nfoPath)
            if (nfoData) {
              updateItem.run({
                item_key: item.item_key,
                title: nfoData.title ?? item.title,
                year: nfoData.year ?? item.year,
                plot: nfoData.plot ?? item.plot,
                genres: nfoData.genres.length > 0 ? JSON.stringify(nfoData.genres) : item.genres,
              })
              imported++
            } else {
              skipped++
            }
          } else {
            skipped++
          }
        } catch {
          skipped++
        }
      }
    })()

    await new Promise<void>((r) => setImmediate(r))
  }

  console.log(
    `[movie-metadata] Imported metadata for ${imported} movies in "${library.name}" (${importMetadataOnly ? 'full' : 'incremental'})`
  )

  return { imported, skipped }
}

/**
 * Check if a media item already has metadata populated.
 * Returns true if ANY of: title, year, plot, or genres are populated.
 */
function hasMetadata(item: {
  title: string | null
  year: number | null
  plot: string | null
  genres: string | null
}): boolean {
  if (item.title) return true
  if (item.year) return true
  if (item.plot) return true
  if (item.genres) return true
  return false
}