import { db, schema } from '../db/index.js'
import { logger } from '../lib/logger.js'
import { eq } from 'drizzle-orm'
import { runFightAsync, isInFight, getActiveFightId } from './orchestrator.js'
import { seedMockBots } from './mock.js'

interface QueueEntry {
  botId: string
  botName: string
  webhookUrl: string
  eloRating: number
  joinedAt: number
  resolve: (fightId: string) => void
  reject: (error: Error) => void
  timeoutHandle: ReturnType<typeof setTimeout>
}

const waitingQueue: QueueEntry[] = []

// How long a bot waits before getting matched against a mock bot
// In production, give real bots time to match (30s). In dev, fall back fast (3s).
const QUEUE_TIMEOUT_MS = Number(process.env.QUEUE_TIMEOUT_MS) || (process.env.NODE_ENV === 'production' ? 30_000 : 3_000)

// Post-fight cooldown tracking
const fightCooldowns = new Map<string, number>()
const COOLDOWN_MS = 15_000

export function setCooldown(botId: string): void {
  fightCooldowns.set(botId, Date.now() + COOLDOWN_MS)
}

export function getQueueSize(): number {
  return waitingQueue.length
}

export function getQueueSnapshot(): { botId: string; botName: string; eloRating: number; waitingSince: number }[] {
  return waitingQueue.map(e => ({
    botId: e.botId,
    botName: e.botName,
    eloRating: e.eloRating,
    waitingSince: e.joinedAt,
  }))
}

/**
 * Join the fight queue. Returns a fightId when matched.
 * If another bot is waiting, matches instantly.
 * If nobody is waiting, waits up to QUEUE_TIMEOUT_MS then fights a mock bot.
 */
export async function joinQueue(botId: string): Promise<string> {
  // Check cooldown
  const cooldownUntil = fightCooldowns.get(botId)
  if (cooldownUntil && Date.now() < cooldownUntil) {
    const waitSec = Math.ceil((cooldownUntil - Date.now()) / 1000)
    throw new Error(`Cooldown active. Wait ${waitSec}s.`)
  }

  // Check if already in a fight — return the fight ID so frontend can redirect
  if (isInFight(botId)) {
    const activeFightId = getActiveFightId(botId)
    const err = new Error('Bot is already in a fight.')
    ;(err as any).fightId = activeFightId
    throw err
  }

  // Load bot
  const botRows = await db.select().from(schema.bots).where(eq(schema.bots.id, botId)).limit(1)
  if (botRows.length === 0) throw new Error('Bot not found')
  const bot = botRows[0]

  // Check if bot is active
  if (!bot.isActive) {
    throw new Error('Bot is deactivated due to webhook errors. Re-test your webhook to reactivate.')
  }

  logger.info('queue', `joinQueue botId=${botId} name=${bot.name} webhook=${bot.webhookUrl}`)

  // Don't allow same bot twice in queue
  const existing = waitingQueue.findIndex(e => e.botId === botId)
  if (existing !== -1) {
    const old = waitingQueue.splice(existing, 1)[0]
    clearTimeout(old.timeoutHandle)
    old.reject(new Error('Rejoined queue'))
  }

  // Check if someone is already waiting -- instant match
  if (waitingQueue.length > 0) {
    // Find closest elo match
    waitingQueue.sort((a, b) => {
      const diffA = Math.abs(a.eloRating - bot.eloRating)
      const diffB = Math.abs(b.eloRating - bot.eloRating)
      return diffA - diffB
    })

    const opponent = waitingQueue.shift()!
    clearTimeout(opponent.timeoutHandle)

    // Start the fight — ensure human players are always botA (left side)
    const isHumanJoiner = bot.webhookUrl === 'http://human.local/'
    const fightId = isHumanJoiner
      ? await startFight(botId, opponent.botId)
      : await startFight(opponent.botId, botId)
    opponent.resolve(fightId)
    return fightId
  }

  // Nobody waiting -- join the queue and wait
  return new Promise<string>((resolve, reject) => {
    const timeoutHandle = setTimeout(async () => {
      const idx = waitingQueue.findIndex(e => e.botId === botId)
      if (idx !== -1) {
        waitingQueue.splice(idx, 1)
        try {
          const fightId = await matchAgainstMock(botId, bot.webhookUrl)
          resolve(fightId)
        } catch (err) {
          reject(err)
        }
      }
    }, QUEUE_TIMEOUT_MS)

    waitingQueue.push({
      botId,
      botName: bot.name,
      webhookUrl: bot.webhookUrl,
      eloRating: bot.eloRating,
      joinedAt: Date.now(),
      resolve,
      reject,
      timeoutHandle,
    })
  })
}

/**
 * Leave the queue without fighting.
 */
export function leaveQueue(botId: string): boolean {
  const idx = waitingQueue.findIndex(e => e.botId === botId)
  if (idx === -1) return false
  const entry = waitingQueue.splice(idx, 1)[0]
  clearTimeout(entry.timeoutHandle)
  entry.reject(new Error('Left queue'))
  return true
}

async function startFight(botAId: string, botBId: string): Promise<string> {
  return runFightAsync(botAId, botBId)
}

async function matchAgainstMock(botId: string, webhookUrl: string): Promise<string> {
  logger.info('queue', `matchAgainstMock botId=${botId} webhook=${webhookUrl}`)
  const allBots = await db.select({
    id: schema.bots.id,
    webhookUrl: schema.bots.webhookUrl,
    eloRating: schema.bots.eloRating,
  }).from(schema.bots)

  const mockBots = allBots.filter(b => b.id !== botId && b.webhookUrl.startsWith('http://mock.local'))

  if (mockBots.length === 0) {
    logger.info('queue', 'No mock bots found, seeding...')
    await seedMockBots()
    return matchAgainstMock(botId, webhookUrl)
  }

  // Pick closest elo mock bot
  const bot = allBots.find(b => b.id === botId)
  const botElo = bot?.eloRating || 1200
  mockBots.sort((a, b) => Math.abs(a.eloRating - botElo) - Math.abs(b.eloRating - botElo))
  const opponent = mockBots[0]

  logger.info('queue', `starting fight: ${botId} vs mock ${opponent.id}`)
  return runFightAsync(botId, opponent.id)
}