import { performance } from 'node:perf_hooks'
import type { Command, State } from '../src/types/screen.js'

export function parseCommand(value: unknown): Command {
  if (!value || typeof value !== 'object') throw new Error('Некорректная команда')
  const c = value as Record<string, unknown>
  if (
    typeof c.id !== 'string' ||
    !/^[a-zA-Z0-9-]{1,80}$/.test(c.id) ||
    typeof c.action !== 'string' ||
    !['play', 'pause', 'stop', 'seek'].includes(c.action) ||
    typeof c.media !== 'string' ||
    !['audio', 'video'].includes(c.media) ||
    typeof c.position !== 'number' ||
    !Number.isFinite(c.position) ||
    c.position < 0 ||
    c.position > 60
  ) {
    throw new Error('Некорректная команда')
  }
  return {
    id: c.id,
    action: c.action as Command['action'],
    media: c.media as Command['media'],
    position: c.position,
  }
}

export class Controller {
  state: State = { revision: 0, command: null, status: 'idle', error: '', samples: [] }
  private seen = new Set<string>()
  private startedAt = 0
  constructor(private publish: (state: State) => void) {}
  command(input: unknown) {
    const command = parseCommand(input)
    if (this.seen.has(command.id)) return
    this.seen.add(command.id)
    // shortcut: помним 4096 команд стенда; долговременная дедупликация — SCREEN-004.
    if (this.seen.size > 4096) this.seen.delete(this.seen.values().next().value!)
    this.startedAt = performance.now()
    this.state = {
      ...this.state,
      revision: this.state.revision + 1,
      command,
      status: 'pending',
      error: '',
    }
    this.publish(this.state)
  }
  report(input: unknown) {
    if (!input || typeof input !== 'object') throw new Error('Некорректный отчёт')
    const r = input as Record<string, unknown>
    if (
      typeof r.status !== 'string' ||
      !['playing', 'paused', 'stopped', 'ended', 'error'].includes(r.status) ||
      typeof r.id !== 'string' ||
      (r.error !== undefined && typeof r.error !== 'string')
    )
      throw new Error('Некорректный отчёт')
    if (
      r.id !== this.state.command?.id ||
      (this.state.status !== 'pending' && r.status !== 'ended' && r.status !== 'error')
    )
      return
    const samples =
      r.status === 'playing' && this.state.command.action === 'play'
        ? [
            ...this.state.samples.slice(-399),
            {
              media: this.state.command.media,
              milliseconds: performance.now() - this.startedAt,
            },
          ]
        : this.state.samples
    this.state = {
      ...this.state,
      revision: this.state.revision + 1,
      status: r.status as State['status'],
      error: String(r.error ?? '').slice(0, 500),
      samples,
    }
    this.publish(this.state)
  }
}