// Bot authentication helper.
// Verifies bot identity via bot_id + secret (SHA256 hash comparison).
// Supports: Authorization header or query params.

import { createHash, timingSafeEqual } from 'crypto'
import { db, schema } from '../db/index.js'
import { eq } from 'drizzle-orm'
import type { Context } from 'hono'
import { extractPubkeyFromAuth } from './jwt.js'

export interface BotAuthContext {
  botId: string
  botName: string
  webhookUrl: string
}

/** Extract and verify bot credentials from request. Returns bot context or error response. */
export async function authenticateBot(c: Context): Promise<BotAuthContext | Response> {
  let botId: string | undefined
  let secret: string | undefined

  // 1. Authorization: Bot <bot_id>:<secret>
  const auth = c.req.header('Authorization')
  if (auth?.startsWith('Bot ')) {
    const parts = auth.slice(4).split(':')
    if (parts.length === 2 && parts[0] && parts[1]) {
      botId = parts[0]
      secret = parts[1]
    }
  }

  // 2. Query params: ?bot_id=xxx&secret=yyy
  if (!botId || !secret) {
    const qBotId = c.req.query('bot_id')
    const qSecret = c.req.query('secret')
    if (qBotId && qSecret) {
      botId = qBotId
      secret = qSecret
    }
  }

  if (!botId || !secret) {
    return c.json({ error: 'Authentication required. Use Authorization: Bot <bot_id>:<secret> or query params ?bot_id=...&secret=...' }, 401)
  }

  const hash = createHash('sha256').update(secret).digest('hex')

  const rows = await db.select({
    id: schema.bots.id,
    name: schema.bots.name,
    secretHash: schema.bots.secretHash,
    webhookUrl: schema.bots.webhookUrl,
  }).from(schema.bots).where(eq(schema.bots.id, botId)).limit(1)

  if (rows.length === 0) {
    return c.json({ error: 'Invalid bot_id or secret.' }, 401)
  }

  // Constant-time comparison using Node's native timingSafeEqual
  const expected = rows[0].secretHash
  if (hash.length !== expected.length ||
      !timingSafeEqual(Buffer.from(hash), Buffer.from(expected))) {
    return c.json({ error: 'Invalid bot_id or secret.' }, 401)
  }

  return {
    botId: rows[0].id,
    botName: rows[0].name,
    webhookUrl: rows[0].webhookUrl,
  }
}

/**
 * Verify the caller owns `botId`, for routes that must accept BOTH audiences:
 * nostr-signed-in owners (web UI's JWT session) and anonymous poll-mode bots
 * (Authorization: Bot <id>:<secret>, which never have a publicKey — see
 * BOTFIGHTS.md). This is the ONLY correct way to check the nostr side: it
 * derives pubkey from a verified JWT (extractPubkeyFromAuth), never from a
 * client-supplied `pubkey` field. A bare `body.pubkey === bot.publicKey`
 * comparison is not an ownership check at all — pubkeys are public by
 * design in nostr (shown on every bot's own profile page), so anyone who's
 * viewed a bot's page could pass that same auth-check with zero secret
 * material. (This exact bug, at POST /api/auth/update, was found and fixed
 * in 09-06 — see auth.ts. Same class, same fix, applied everywhere ownership
 * is checked by pubkey.)
 */
export async function verifyBotOwner(c: Context, botId: string): Promise<true | Response> {
  const auth = c.req.header('Authorization')
  if (auth?.startsWith('Bearer ')) {
    const pubkey = extractPubkeyFromAuth(auth)
    if (!pubkey) {
      return c.json({ error: 'Invalid or expired session.' }, 401)
    }
    const rows = await db.select({ publicKey: schema.bots.publicKey })
      .from(schema.bots).where(eq(schema.bots.id, botId)).limit(1)
    if (rows.length === 0 || rows[0].publicKey !== pubkey) {
      return c.json({ error: 'Unauthorized' }, 403)
    }
    return true
  }

  const botOrRes = await authenticateBot(c)
  if (botOrRes instanceof Response) return botOrRes
  if (botOrRes.botId !== botId) {
    return c.json({ error: 'Unauthorized' }, 403)
  }
  return true
}