// ── Economics, as the site sees it (PLAN_REDESIGNS §11.2.2, D199, D335, D336) ─
//
// Wulf's Economics is optional (D199): a server reports it in hello's
// `integrations.economics`, and every surface that needs it refuses with a
// reason where it is absent, never quietly. Three readers share this file:
//
//   • the step (`rust.coins.pay`, in eventRewards.js), which asks whether the
//     server has Economics before it pays anybody;
//   • the player's own page and the app, which read each linked account's
//     balance live and fall back to the last one the tally carried;
//   • staff, who deposit, withdraw or set one player's balance.
//
// The starting balance matters to D336: the richest column and the Magnate
// title rank only balances above it, because Economics answers it for an
// account it has never seen (§11.2.1). The plugin reads it from Economics'
// config; when that file cannot be read the site assumes Economics' default,
// 1000, and says so (`startingKnown: false`).

const core = require('../../core')

const client = require('../../sidecarClient')
const db = require('./economics.db')
const eventsDb = require('../events/events.db')
const servers = require('../servers/servers.model')
const { pluginError, transportError } = require('../../eventLeases')

const log = core.logger('economics')

/** Economics' own default starting balance, assumed when its config cannot be read. */
const DEFAULT_STARTING_BALANCE = 1000

/** The sentence every surface says where a server has no Economics (D199). */
const MISSING = 'Economics is not installed on this server'

const OPS = ['deposit', 'withdraw', 'set']

/** The plugin's bounds (PROTOCOL.md §20.3), refused here first so a form says why. */
const AMOUNT_MIN = 0.01
const AMOUNT_MAX = 1000000

/** JSON_EXTRACT comes back as text from the driver; an object passes through. */
function parse(value) {
  if (value === null || value === undefined) return null
  if (typeof value === 'object') return value
  try {
    return JSON.parse(value)
  } catch {
    return null
  }
}

/**
 * A server's Economics as its last hello said: `{ loaded: false }`, or loaded
 * with its version, its starting balance (assumed where unread) and whether
 * balances wipe with the map.
 */
function shape(raw) {
  const e = parse(raw)
  if (!e || e.loaded !== true) return { loaded: false }

  const start = Number(e.startingBalance)
  const known = e.startingBalance !== undefined && e.startingBalance !== null && Number.isFinite(start)

  return {
    loaded: true,
    version: typeof e.version === 'string' ? e.version : null,
    startingBalance: known ? start : DEFAULT_STARTING_BALANCE,
    startingKnown: known,
    wipesWithMap: typeof e.wipesWithMap === 'boolean' ? e.wipesWithMap : null,
  }
}

/** One server's report, with the wipe it is on. `{ loaded: false }` for a server never heard from. */
async function forServer(serverId) {
  const row = await db.reportFor(serverId)
  if (!row) return { loaded: false, wipeId: null }
  return { ...shape(row.economics), wipeId: row.wipeId || null }
}

/** Every server's report, keyed by id. */
async function byServer() {
  const rows = await db.reports()
  return new Map(rows.map((r) => [r.serverId, { ...shape(r.economics), wipeId: r.wipeId || null }]))
}

/** An amount as a sentence says it: thousands separated, at most two places. */
function coins(n) {
  return Number(n).toLocaleString('en-US', { maximumFractionDigits: 2 })
}

/**
 * The balances of some Steam accounts on every enabled server: live where the
 * server answers, the last balance the tally carried where it does not, and
 * null where neither knows. A server without Economics is listed with the reason,
 * so a page can say why there is nothing rather than show nothing.
 *
 * @param {Array<{steamId, name}>} accounts  the accounts to read, a user's links
 */
async function balancesOf(accounts) {
  const ids = [...new Set(accounts.map((a) => String(a.steamId)).filter(Boolean))]
  const [list, reports] = await Promise.all([servers.listForPolling(), byServer()])

  return Promise.all(
    list.map(async (server) => {
      const econ = reports.get(server.id) || { loaded: false }
      const base = { serverId: server.id, server: server.name || server.id }

      if (!econ.loaded) return { ...base, economics: false, reason: MISSING, accounts: [] }

      const known = await eventsDb.balancesFor(server.id, econ.wipeId, ids)
      const live = new Map()
      let answered = false

      if (ids.length) {
        const result = await client.economicsBalances(server, ids)
        const data = (result.ok && result.data) || {}
        if (data.kind === 'economics.balances') {
          answered = true
          for (const row of data.balances || []) {
            if (row && row.steamId && Number.isFinite(Number(row.balance))) live.set(String(row.steamId), Number(row.balance))
          }
        }
      }

      return {
        ...base,
        economics: true,
        startingBalance: econ.startingBalance,
        startingKnown: econ.startingKnown,
        live: answered,
        accounts: accounts.map((a) => {
          const id = String(a.steamId)
          const source = live.has(id) ? 'live' : known.has(id) ? 'last-known' : null
          return {
            steamId: id,
            name: a.name || null,
            balance: source === 'live' ? live.get(id) : source ? known.get(id) : null,
            source,
          }
        }),
      }
    }),
  )
}

/** Checks a staff adjustment's op and amount. `{ ok }` or `{ ok: false, message }`. */
function checkAdjustment(op, amount) {
  if (!OPS.includes(op)) return { ok: false, message: `op is one of ${OPS.join(', ')}` }
  const value = Number(amount)
  const min = op === 'set' ? 0 : AMOUNT_MIN
  if (!Number.isFinite(value) || value < min || value > AMOUNT_MAX) {
    return { ok: false, message: `an amount is ${op === 'set' ? '0' : coins(AMOUNT_MIN)} to ${coins(AMOUNT_MAX)} coins` }
  }
  return { ok: true, value: Math.round(value * 100) / 100 }
}

/**
 * Staff deposit, withdraw or set one player's balance on one server.
 *
 * Resolves `{ ok: true, before, after, repeat, server }` or `{ ok: false,
 * status, message, reason? }`. The key makes a resent form harmless: the plugin
 * answers a key it has seen from the first reply, and moves nothing.
 */
async function adjust({ serverId, steamId, op, amount, key }) {
  const checked = checkAdjustment(op, amount)
  if (!checked.ok) return { ok: false, status: 400, message: checked.message }

  const server = await servers.getForCalling(serverId)
  if (!server) return { ok: false, status: 404, message: 'No such server' }

  const econ = await forServer(server.id)
  if (!econ.loaded) return { ok: false, status: 409, reason: 'economics-missing', message: MISSING }

  const result = await client.economicsAdjust(server, { key, steamId, op, amount: checked.value })
  if (!result.ok) return { ok: false, status: 503, message: transportError(server, result, 'Economics') }

  const data = result.data || {}
  const name = server.name || server.id

  if (data.kind === 'economics.adjusted') {
    return { ok: true, before: Number(data.before), after: Number(data.after), repeat: Boolean(data.repeat), server: name, amount: checked.value }
  }

  if (data.reason === 'insufficient') {
    // Economics takes all or nothing (§11.2.1), so the sentence is the balance.
    return { ok: false, status: 409, reason: 'insufficient', message: `They have only ${coins(data.balance)} coins on ${name}` }
  }

  log.warn('Economics refused an adjustment', { server: server.id, op, reason: data.reason })
  return {
    ok: false,
    status: data.reason === 'economics-missing' ? 409 : 400,
    reason: data.reason || null,
    message: pluginError(data, `${name} refused the adjustment`),
  }
}

/** The activity row's sentence: "Deposited 500 coins to Wanderer on Main: 1,000 → 1,500". */
function adjustmentSummary({ op, amount, name, server, before, after }) {
  const verb = { deposit: `Deposited ${coins(amount)} coins to`, withdraw: `Withdrew ${coins(amount)} coins from`, set: `Set the balance of` }[op]
  return `${verb} ${name} on ${server}${op === 'set' ? ` to ${coins(amount)}` : ''}: ${coins(before)} → ${coins(after)}`
}

module.exports = {
  DEFAULT_STARTING_BALANCE,
  MISSING,
  OPS,
  AMOUNT_MIN,
  AMOUNT_MAX,
  shape,
  forServer,
  byServer,
  coins,
  balancesOf,
  checkAdjustment,
  adjust,
  adjustmentSummary,
}