import type { HttpContext } from '@adonisjs/core/http'
import env from '#start/env'
import NzbService from '#services/nzb_service'
import SearchService from '#services/search_service'
import { capsXml, errorXml, expandCategories, resultsXml, type NewznabServer } from '#lib/newznab/index'

const LIMITS = { max: 100, default: 50 }

/** Search functions and the category each defaults to when `cat` is absent. */
const SEARCH_FUNCTIONS: Record<string, number | undefined> = {
  'search': undefined,
  'tvsearch': 5000,
  'tv-search': 5000,
  'movie': 2000,
  'movie-search': 2000,
  'music': 3000,
  'audio': 3000,
  'book': 7000,
}

/** The configured key, if any. */
function configuredApiKey(): string | undefined {
  const value: any = env.get('NEWZNAB_API_KEY')
  const key = typeof value === 'string' ? value : value?.release()
  return key || undefined
}

function int(value: unknown): number | undefined {
  return typeof value === 'string' && /^\d+$/.test(value) ? Number(value) : undefined
}

/**
 * Newznab API for Prowlarr, Sonarr, Radarr and the like (from voyager 1):
 * GET /api?t=caps|search|tvsearch|movie|music|book|get&apikey=…
 * Releases with readable names that aren't known to miss files.
 */
export default class NewznabController {
  async handle({ request, response }: HttpContext) {
    const qs = request.qs()
    const t = String(qs.t ?? '')
    const server = this.server(request)
    const xml = (body: string, type = 'application/xml') => {
      response.header('Content-Type', `${type}; charset=utf-8`)
      return response.send(body)
    }

    const apiKey = configuredApiKey()
    if (apiKey && qs.apikey !== apiKey) return xml(errorXml(100, 'Incorrect user credentials'))
    if (t === 'caps') return xml(capsXml(server, LIMITS))

    if (t === 'get') {
      const id = int(qs.id)
      if (id === undefined) return xml(errorXml(200, 'Missing parameter (id)'))
      const nzb = await NzbService.build(id)
      if (!nzb) return xml(errorXml(300, 'No such item'))
      const filename = `${nzb.name.replace(/[^\w.\-()[\] ]+/g, '_').slice(0, 180) || 'release'}.nzb`
      response.header('Content-Disposition', `attachment; filename="${filename}"`)
      return xml(nzb.xml, 'application/x-nzb')
    }

    if (!(t in SEARCH_FUNCTIONS)) return xml(errorXml(202, `No such function (${t || 'none'})`))

    const requested = String(qs.cat ?? '')
      .split(',')
      .map((c) => int(c.trim()))
      .filter((c): c is number => c !== undefined)
    const fallback = SEARCH_FUNCTIONS[t]
    const categories = expandCategories(requested.length ? requested : fallback ? [fallback] : [])
    const limit = Math.min(int(qs.limit) ?? LIMITS.default, LIMITS.max)
    const offset = int(qs.offset) ?? 0

    // ID-only lookups (tvdbid, imdbid, …) aren't supported: an empty result rather than everything.
    const q = typeof qs.q === 'string' ? qs.q.trim() : ''
    const idOnly = !q && ['tvdbid', 'tvmazeid', 'rid', 'imdbid', 'tmdbid'].some((p) => qs[p])
    const result = idOnly
      ? null
      : await SearchService.search({
          q,
          categories,
          readable: true,
          notIncomplete: true,
          maxAgeDays: int(qs.maxage),
          season: int(qs.season),
          episode: int(qs.season) !== undefined ? int(qs.ep) : undefined,
          sort: 'newest',
          perPage: limit,
          offset,
        })

    const items = (result?.releases ?? []).map((r) => {
      const tv = /(?:^|[._ -])S(\d{1,2})E(\d{1,3})/i.exec(r.name)
      return {
        id: r.id,
        title: r.name,
        category: r.category ?? 8010,
        size: r.size,
        files: r.fileCount,
        postedAt: r.postedAt ? new Date(r.postedAt) : null,
        poster: r.poster,
        groups: r.groups ?? [],
        // Passwords come with phase 2 (archive inspection).
        password: false,
        season: tv ? `S${tv[1].padStart(2, '0')}` : undefined,
        episode: tv ? `E${tv[2].padStart(2, '0')}` : undefined,
      }
    })
    return xml(resultsXml(server, items, offset, result?.total ?? 0), 'application/rss+xml')
  }

  private server(request: HttpContext['request']): NewznabServer {
    const proto = request.header('x-forwarded-proto') ?? 'http'
    const host = request.header('x-forwarded-host') ?? request.header('host') ?? 'localhost'
    return { title: 'Voyager 2', baseUrl: `${proto}://${host}`, apiKey: configuredApiKey() }
  }
}