// ── uo-link sidecar REST client ────────────────────────────────────────────
//
// Server-side HTTP client for the uo-link sidecar (the bridge to the ServUO
// shard). Same shape as botInternalClient: never throws — every call returns
// { ok, data, status, error } so an admin poll or a public page never 500s just
// because the sidecar/shard is down or restarting.
//
// The base URL + shared-secret token come from the DB-backed uoLinkConfig
// (admin-managed, encrypted at rest) — NOT env vars, and the token is NEVER sent
// to the browser. Every request carries `Authorization: Bearer <token>` and
// `X-UOLink-Version: <protocol>` so a protocol mismatch is caught (409) rather
// than mis-parsed. Config is cached for a few seconds to avoid decrypting the
// token on every call.

const uoLinkConfig = require('../model/uoLinkConfig/uoLinkConfig.model')
const log = require('./logger')('uo-link-client')

const TIMEOUT_MS = 12000 // sidecar waits up to 10s on the shard before 504
const CONFIG_TTL_MS = 5000

let cachedConfig = null
let cachedAt = 0

// Read (and briefly cache) the connection config incl. decrypted token.
async function resolveConfig() {
  const now = Date.now()
  if (cachedConfig && now - cachedAt < CONFIG_TTL_MS) return cachedConfig
  cachedConfig = await uoLinkConfig.getWithToken()
  cachedAt = now
  return cachedConfig
}

// Drop the cache after a save so the next call picks up new URL/token immediately.
function invalidateConfig() {
  cachedConfig = null
  cachedAt = 0
}

// Core request. Returns { ok, data, status, error }. `ok` is true only on a 2xx
// with a parseable JSON body. Non-2xx responses still return their status + body
// so callers can distinguish 503 (shard restarting — transient) from 404.
async function call(path, { method = 'GET', body } = {}) {
  const config = await resolveConfig()
  if (!config || !config.baseUrl) {
    return { ok: false, status: 0, error: 'uo-link is not configured' }
  }

  const controller = new AbortController()
  const timeout = setTimeout(() => controller.abort(), TIMEOUT_MS)
  try {
    const headers = {
      'Content-Type': 'application/json',
      'X-UOLink-Version': String(config.protocol || 1),
    }
    if (config.token) headers.Authorization = `Bearer ${config.token}`

    const res = await fetch(`${config.baseUrl}${path}`, {
      method,
      headers,
      body: body ? JSON.stringify(body) : undefined,
      signal: controller.signal,
    })

    let data = null
    try {
      data = await res.json()
    } catch {
      // Non-JSON (or empty) body — leave data null; status still reported.
    }

    if (!res.ok) {
      if (res.status === 401) log.warn('uo-link rejected auth token (401)', { path })
      if (res.status === 409) log.error('uo-link protocol mismatch (409)', { path, body: data })
      return { ok: false, status: res.status, data, error: `sidecar responded ${res.status}` }
    }
    return { ok: true, status: res.status, data }
  } catch (err) {
    log.warn('uo-link call failed', { path, message: err.message })
    return { ok: false, status: 0, error: err.message }
  } finally {
    clearTimeout(timeout)
  }
}

// ── Read queries ───────────────────────────────────────────────────────────
// Liveness (no auth required by the sidecar, but we send it anyway).
const health = () => call('/health')
const getCharBySerial = (serial) => call(`/char/serial/${encodeURIComponent(serial)}`)
const getCharBySlot = (account, slot) =>
  call(`/char/${encodeURIComponent(account)}/${encodeURIComponent(slot)}`)
const getRoster = (account) => call(`/roster/${encodeURIComponent(account)}`)
const getVendors = (account) => call(`/vendors/${encodeURIComponent(account)}`)

// History / economy series — used for WS-reconnect backfill and public feeds.
function getHistory({ kind, limit = 100 } = {}) {
  const params = new URLSearchParams()
  if (kind) params.set('kind', kind)
  if (limit) params.set('limit', String(limit))
  const qs = params.toString()
  return call(`/history${qs ? `?${qs}` : ''}`)
}
const getEconomy = (limit = 100) => call(`/economy?limit=${encodeURIComponent(limit)}`)

// ── Commands ──────────────────────────────────────────────────────────────
const confirmLink = (code, websiteUserId) =>
  call('/link/confirm', { method: 'POST', body: { code, websiteUserId: String(websiteUserId) } })
const linkLookup = (account) => call(`/link/${encodeURIComponent(account)}`)
const postTownCrier = ({ id, lines, durationSec }) =>
  call('/towncrier', { method: 'POST', body: { id, lines, durationSec } })
const deleteTownCrier = (id) => call(`/towncrier/${encodeURIComponent(id)}`, { method: 'DELETE' })

module.exports = {
  invalidateConfig,
  health,
  getCharBySerial,
  getCharBySlot,
  getRoster,
  getVendors,
  getHistory,
  getEconomy,
  confirmLink,
  linkLookup,
  postTownCrier,
  deleteTownCrier,
}