/**
 * Logical FD registry, sigaction, and snapshot-handle methods on kernel `ctx`.
 */
import {
  bareOsIsPosixSignalName,
  bareOsNormalizeSignalName
} from './bare-os-posix-signals.js'

export function createBareOsLogicalFdMethods() {
  return {
    /**
     * @param {number} fd
     * @param {string} target
     */
    bareOsRegisterLogicalFd(fd, target) {
      const n = Number(fd)
      if (!Number.isFinite(n) || n < 0 || n > 65535) return
      const k = String(n >>> 0)
      if (k === '0' || k === '1' || k === '2') return
      this.bareOsLogicalFds[k] = String(target || '')
    },
    /** @param {number} fd */
    bareOsUnregisterLogicalFd(fd) {
      const k = String(Number(fd) >>> 0)
      if (this.bareOsLogicalFds && typeof this.bareOsLogicalFds === 'object') {
        delete this.bareOsLogicalFds[k]
      }
      if (
        this.bareOsLogicalFdFlags &&
        typeof this.bareOsLogicalFdFlags === 'object'
      ) {
        delete this.bareOsLogicalFdFlags[k]
      }
    },
    /**
     * Logical `sigaction`: `IGNORE` suppresses synthetic delivery for this signal.
     * @param {string} signal
     * @param {'IGNORE' | 'DEFAULT' | 'IGN' | 'DEF'} mode
     */
    bareOsSigaction(signal, mode) {
      const s = bareOsNormalizeSignalName(signal)
      if (!bareOsIsPosixSignalName(signal) || s === '0') {
        throw new Error('bareOsSigaction: unsupported signal')
      }
      const m = String(mode || 'DEFAULT')
        .toUpperCase()
        .replace(/^SIG/i, '')
      if (m === 'DEFAULT' || m === 'DEF') {
        if (this.bareOsLogicalSigaction) delete this.bareOsLogicalSigaction[s]
        return { ok: true, signal: s, mode: 'DEFAULT' }
      }
      if (m === 'IGNORE' || m === 'IGN') {
        if (!this.bareOsLogicalSigaction) {
          throw new Error('bareOsSigaction: internal state missing')
        }
        this.bareOsLogicalSigaction[s] = 'IGNORE'
        return { ok: true, signal: s, mode: 'IGNORE' }
      }
      throw new Error('bareOsSigaction: mode must be IGNORE or DEFAULT')
    },
    /** @param {Record<string, unknown>} desc */
    bareOsRegisterSnapshotHandle(desc) {
      if (!desc || typeof desc !== 'object') return
      if (!Array.isArray(this.bareOsSnapshotHandles)) {
        this.bareOsSnapshotHandles = []
      }
      const id =
        typeof desc.id === 'string' && desc.id.trim()
          ? desc.id.trim().slice(0, 128)
          : `snap-${this.bareOsSnapshotHandles.length}`
      this.bareOsSnapshotHandles.push({ ...desc, id, atMs: Date.now() })
    }
  }
}