/**
 * Lightweight arg validation for PearData RPCs.
 */

export const SCHEMA_VERSION = 1

/**
 * @typedef {{ ok: true, args: object } | { ok: false, error: string }} ValidateResult
 */

/**
 * @param {string} method
 * @param {object} args
 * @returns {ValidateResult}
 */
export function validateMethodArgs(method, args = {}) {
  if (args == null || typeof args !== 'object' || Array.isArray(args)) {
    return { ok: false, error: 'Arguments must be a plain object' }
  }

  switch (method) {
    case 'handshake':
    case 'ping':
    case 'getServerInfo':
    case 'getAuthStatus':
    case 'getNodeInfo':
    case 'getHealth':
    case 'listContexts':
    case 'listCharts':
    case 'listAnomalies':
    case 'listAlerts':
    case 'listJobs':
    case 'listPeers':
    case 'getWeights':
    case 'getHostSnapshot':
    case 'investigateHost':
    case 'getDbInfo':
    case 'listPeerLinks':
    case 'listChildPeers':
    case 'getFleetHealth':
    case 'getStorageInfo':
    case 'getRetentionConfig':
      return { ok: true, args }

    case 'hotMetrics': {
      const limit = args.limit == null ? 15 : Number(args.limit)
      if (!Number.isFinite(limit) || limit < 1 || limit > 50) {
        return { ok: false, error: 'limit must be 1..50' }
      }
      const window = args.window == null ? 120 : Number(args.window)
      if (!Number.isFinite(window) || window < 20 || window > 600) {
        return { ok: false, error: 'window must be 20..600' }
      }
      return {
        ok: true,
        args: {
          ...args,
          limit,
          window,
          family: args.family != null ? String(args.family) : '',
        },
      }
    }

    case 'relatedCharts': {
      const chart = String(args.chart || args.id || '').trim()
      if (!chart) return { ok: false, error: 'chart or id is required' }
      const limit = args.limit == null ? 12 : Number(args.limit)
      if (!Number.isFinite(limit) || limit < 1 || limit > 40) {
        return { ok: false, error: 'limit must be 1..40' }
      }
      return { ok: true, args: { ...args, chart, id: chart, limit } }
    }

    case 'compareChartWindows': {
      const chart = String(args.chart || args.id || '').trim()
      if (!chart) return { ok: false, error: 'chart or id is required' }
      const points = args.points == null ? 60 : Number(args.points)
      if (!Number.isFinite(points) || points < 1 || points > 300) {
        return { ok: false, error: 'points must be 1..300' }
      }
      return { ok: true, args: { ...args, chart, id: chart, points } }
    }

    case 'summarizeCharts': {
      let charts = args.charts
      if (typeof charts === 'string') {
        charts = charts.split(/[\s,]+/).filter(Boolean)
      }
      if (!Array.isArray(charts) || !charts.length) {
        return { ok: false, error: 'charts array required' }
      }
      charts = charts.map(String).slice(0, 12)
      const points = args.points == null ? 60 : Number(args.points)
      if (!Number.isFinite(points) || points < 1 || points > 120) {
        return { ok: false, error: 'points must be 1..120' }
      }
      return {
        ok: true,
        args: {
          ...args,
          charts,
          points,
          after: args.after != null ? Number(args.after) : -120,
        },
      }
    }

    case 'searchCharts': {
      const limit = args.limit == null ? 30 : Number(args.limit)
      if (!Number.isFinite(limit) || limit < 1 || limit > 100) {
        return { ok: false, error: 'limit must be 1..100' }
      }
      return {
        ok: true,
        args: {
          ...args,
          q: args.q != null ? String(args.q) : '',
          limit,
        },
      }
    }

    case 'summarizeChart': {
      const chart = String(args.chart || args.id || '').trim()
      if (!chart) return { ok: false, error: 'chart or id is required' }
      const points = args.points == null ? 90 : Number(args.points)
      if (!Number.isFinite(points) || points < 1 || points > 600) {
        return { ok: false, error: 'points must be 1..600' }
      }
      return {
        ok: true,
        args: {
          ...args,
          chart,
          id: chart,
          points,
          after: args.after != null ? Number(args.after) : -Math.min(points, 300),
          group: String(args.group || 'average'),
        },
      }
    }

    case 'queryLogs': {
      const source = String(args.source || 'journal').toLowerCase()
      if (!['anomaly', 'audit', 'journal'].includes(source)) {
        return { ok: false, error: 'source must be anomaly|audit|journal' }
      }
      const limit = args.limit == null ? 200 : Number(args.limit)
      if (!Number.isFinite(limit) || limit < 1 || limit > 2000) {
        return { ok: false, error: 'limit must be 1..2000' }
      }
      return {
        ok: true,
        args: {
          ...args,
          source,
          limit,
          q: args.q != null ? String(args.q) : '',
          priority: args.priority != null ? String(args.priority) : '',
          unit: args.unit != null ? String(args.unit) : '',
          cursor: args.cursor != null ? Number(args.cursor) : 0,
        },
      }
    }

    case 'listProcesses': {
      const sort = String(args.sort || 'cpu').toLowerCase()
      const allowedSort = [
        'cpu',
        'rss',
        'pid',
        'name',
        'io',
        'threads',
        'age',
        'fds',
        'state',
      ]
      if (!allowedSort.includes(sort)) {
        return { ok: false, error: `sort must be ${allowedSort.join('|')}` }
      }
      const order = String(args.order || 'desc').toLowerCase() === 'asc' ? 'asc' : 'desc'
      const filter = String(args.filter || 'all').toLowerCase()
      const allowedFilter = [
        'all',
        'running',
        'sleeping',
        'zombie',
        'stopped',
        'highcpu',
        'highmem',
        'hasio',
        'kernel',
        'user',
      ]
      if (!allowedFilter.includes(filter)) {
        return { ok: false, error: `filter must be ${allowedFilter.join('|')}` }
      }
      const limit = args.limit == null ? 250 : Number(args.limit)
      if (!Number.isFinite(limit) || limit < 1 || limit > 2000) {
        return { ok: false, error: 'limit must be 1..2000' }
      }
      const offset = args.offset == null ? 0 : Number(args.offset)
      if (!Number.isFinite(offset) || offset < 0) {
        return { ok: false, error: 'offset must be ≥ 0' }
      }
      const pid =
        args.pid == null || args.pid === ''
          ? null
          : Number(args.pid)
      if (pid != null && (!Number.isFinite(pid) || pid < 1)) {
        return { ok: false, error: 'pid must be a positive number' }
      }
      return {
        ok: true,
        args: {
          ...args,
          sort,
          order,
          filter,
          limit: Math.floor(limit),
          offset: Math.floor(offset),
          q: args.q != null ? String(args.q) : '',
          pid,
        },
      }
    }

    case 'setDisplayName': {
      const name = String(args.name ?? '').trim()
      if (!name) return { ok: false, error: 'name is required' }
      if (name.length > 40) return { ok: false, error: 'name must be ≤ 40 characters' }
      return { ok: true, args: { ...args, name } }
    }

    case 'getContext':
    case 'getChart':
    case 'getAlert': {
      const id = String(args.id || args.chart || args.context || '').trim()
      if (!id) return { ok: false, error: 'id is required' }
      return { ok: true, args: { ...args, id } }
    }

    case 'queryData': {
      const chart = String(args.chart || args.context || '').trim()
      if (!chart) return { ok: false, error: 'chart or context is required' }
      const points = args.points == null ? 60 : Number(args.points)
      if (!Number.isFinite(points) || points < 1 || points > 10_000) {
        return { ok: false, error: 'points must be 1..10000' }
      }
      return {
        ok: true,
        args: {
          ...args,
          chart,
          points,
          after: args.after != null ? Number(args.after) : -points,
          before: args.before != null ? Number(args.before) : 0,
          group: String(args.group || 'average'),
          format: String(args.format || 'json'),
        },
      }
    }

    case 'subscribeMetrics': {
      const charts = Array.isArray(args.charts)
        ? args.charts.map(String)
        : args.chart
          ? [String(args.chart)]
          : ['*']
      const intervalMs = Math.max(500, Number(args.intervalMs) || 1000)
      return { ok: true, args: { ...args, charts, intervalMs } }
    }

    case 'unsubscribeMetrics':
    case 'unsubscribeAnomalies':
      return { ok: true, args }

    case 'subscribeAnomalies':
      return { ok: true, args }

    case 'setAlertConfig': {
      const id = String(args.id || '').trim()
      if (!id) return { ok: false, error: 'id is required' }
      return { ok: true, args: { ...args, id } }
    }

    case 'ackAlert':
    case 'silenceAlert': {
      const id = String(args.id || '').trim()
      if (!id) return { ok: false, error: 'id is required' }
      return { ok: true, args: { ...args, id } }
    }

    case 'runJob': {
      const name = String(args.name || args.job || '').trim()
      if (!name) return { ok: false, error: 'name is required' }
      return { ok: true, args: { ...args, name } }
    }

    case 'cancelJob': {
      const id = String(args.id || '').trim()
      if (!id) return { ok: false, error: 'id is required' }
      return { ok: true, args: { ...args, id } }
    }

    case 'mintInvite': {
      const role = String(args.role || 'operator').toLowerCase()
      if (!['viewer', 'operator', 'admin'].includes(role)) {
        return { ok: false, error: 'role must be viewer|operator|admin' }
      }
      return { ok: true, args: { ...args, role } }
    }

    case 'revokePeer': {
      const peerId = String(args.peerId || '').toLowerCase()
      if (!/^[0-9a-f]{64}$/.test(peerId)) {
        return { ok: false, error: 'peerId must be 64 hex characters' }
      }
      return { ok: true, args: { ...args, peerId } }
    }

    case 'getAllMetrics': {
      const format = String(args.format || 'json').toLowerCase()
      if (!['json', 'prometheus', 'shell'].includes(format)) {
        return { ok: false, error: 'format must be json|prometheus|shell' }
      }
      return { ok: true, args: { ...args, format } }
    }

    case 'exportSnapshot':
      return { ok: true, args }

    case 'setRetentionConfig': {
      const patch = args && typeof args === 'object' ? { ...args } : {}
      delete patch.success
      return { ok: true, args: patch }
    }

    case 'pruneHistory': {
      return {
        ok: true,
        args: {
          dryRun: Boolean(args?.dryRun),
          beforeMs: args?.beforeMs != null ? Number(args.beforeMs) : undefined,
          force: Boolean(args?.force),
          // undefined = default on; false disables clearUnlinked+compact
          gc: args?.gc === false ? false : args?.gc === true ? true : undefined,
        },
      }
    }

    case 'linkPeer': {
      const remotePublicKey = String(args.remotePublicKey || args.peerId || '').toLowerCase()
      if (!/^[0-9a-f]{64}$/.test(remotePublicKey)) {
        return { ok: false, error: 'remotePublicKey must be 64 hex characters' }
      }
      const syncMode = String(args.syncMode || 'both')
      if (!['push', 'pull', 'both'].includes(syncMode)) {
        return { ok: false, error: 'syncMode must be push|pull|both' }
      }
      return { ok: true, args: { ...args, remotePublicKey, syncMode } }
    }

    case 'unlinkPeer': {
      const remotePublicKey = String(args.remotePublicKey || args.peerId || '').toLowerCase()
      if (!/^[0-9a-f]{64}$/.test(remotePublicKey)) {
        return { ok: false, error: 'remotePublicKey must be 64 hex characters' }
      }
      return { ok: true, args: { ...args, remotePublicKey } }
    }

    default:
      return { ok: true, args }
  }
}