import { BaseCommand, args, flags } from '@adonisjs/core/ace'
import { CommandOptions } from '@adonisjs/core/types/ace'
import Group from '#models/group'
import NntpService from '#services/NntpService'
import { parseGroupResponse } from '#lib/nntp/group'

/**
 * Adds newsgroups to index (or reactivates them). The scheduler picks them
 * up on its next tick, starting INDEX_INITIAL_BACKFILL articles back.
 */
export default class GroupAdd extends BaseCommand {
  public static commandName = 'group:add'
  public static description = 'Adds newsgroups to index.'

  public static options: CommandOptions = {
    startApp: true,
  }

  @args.spread({ description: 'Group names, e.g. alt.binaries.hdtv' })
  declare names: string[]

  @flags.boolean({ description: 'Deactivate the groups instead' })
  declare disable: boolean

  @flags.boolean({
    description: 'Also download bodies to identify obfuscated posts (one body per article; bandwidth-heavy)',
  })
  declare bodies: boolean

  @flags.number({ description: 'Start this many articles back instead of INDEX_INITIAL_BACKFILL (new groups only)' })
  declare backfill?: number

  @flags.boolean({ description: 'With --backfill: also for groups indexed before, skipping what was missed since' })
  declare reset: boolean

  @flags.boolean({ description: "Start at the server's oldest article: the group's full history (also for groups indexed before)" })
  declare fromStart: boolean

  public async run() {
    for (const name of this.names) {
      if (!/^[a-z0-9][a-z0-9.+_-]*$/i.test(name)) {
        this.logger.error(`Not a valid group name: ${name}`)
        continue
      }
      const group = await Group.firstOrCreate({ name }, { name, active: !this.disable, fetchBodies: this.bodies })
      group.active = !this.disable
      if (this.bodies) group.fetchBodies = true
      if (this.fromStart) {
        // The scheduler continues after last_queued_id; 0 would mean "new group" to it.
        const { first } = await this.groupInfo(name)
        group.lastQueuedId = first > 1n ? first - 1n : 1n
        group.lastIndexedId = group.lastQueuedId
      } else if (this.backfill !== undefined && (this.reset || BigInt(group.lastQueuedId ?? 0) === 0n)) {
        const { last } = await this.groupInfo(name)
        group.lastQueuedId = (last > BigInt(this.backfill) ? last - BigInt(this.backfill) : 0n)
        group.lastIndexedId = group.lastQueuedId
      }
      await group.save()
      this.logger.info(
        `${name}: ${group.active ? 'active' : 'inactive'}, bodies ${group.fetchBodies ? 'on' : 'off'}` +
          (this.backfill !== undefined || this.fromStart ? `, starting after article ${group.lastQueuedId}` : '')
      )
    }
    if (this.backfill !== undefined || this.fromStart) await NntpService.shutdown()
  }

  private async groupInfo(name: string) {
    const conn = await NntpService.acquire()
    let failed = false
    try {
      return parseGroupResponse((await conn.group(name)).resp)
    } catch (error) {
      failed = true
      throw error
    } finally {
      NntpService.release(conn, failed)
    }
  }
}