import { appendFileSync, mkdirSync, renameSync, rmSync, statSync } from 'node:fs'
import { join } from 'node:path'

type Event =
  | 'app-start'
  | 'app-stop'
  | 'startup-error'
  | 'settings-error'
  | 'invalid-report'
  | 'output-open'
  | 'output-close'
  | 'media-error'
  | 'connection'
  | 'package'
const fields: Partial<Record<Event, Record<string, readonly string[]>>> = {
  'output-close': {
    reason: [
      'operator',
      'display',
      'power',
      'fullscreen',
      'renderer',
      'document',
      'geometry',
      'unresponsive',
    ],
  },
  'media-error': { channel: ['main', 'music', 'scene'] },
  connection: { status: ['disabled', 'waiting', 'connected', 'offline', 'expired'] },
  package: { action: ['download', 'check', 'remove'], status: ['success', 'failed'] },
}
const events: readonly string[] = [
  'app-start',
  'app-stop',
  'startup-error',
  'settings-error',
  'invalid-report',
  'output-open',
  'output-close',
  'media-error',
  'connection',
  'package',
]
export class DiagnosticLog {
  private disabled = false
  constructor(
    private directory: string,
    private limit = 1024 * 1024,
  ) {}
  record(event: Event, data: Record<string, unknown> = {}) {
    if (this.disabled || !events.includes(event)) return
    const entry: Record<string, string> = { time: new Date().toISOString(), event }
    // Только разрешённые значения: никаких Error.message, URL, токенов или состояния игры.
    for (const [key, allowed] of Object.entries(fields[event] ?? {})) {
      if (typeof data[key] !== 'string' || !allowed.includes(data[key])) return
      entry[key] = data[key]
    }
    if (event === 'app-start') {
      for (const key of ['version', 'electron'] as const) {
        if (typeof data[key] !== 'string' || !/^\d+\.\d+\.\d+(?:-[a-zA-Z0-9.-]+)?$/.test(data[key]))
          return
        entry[key] = data[key]
      }
      if (
        !['linux', 'darwin', 'win32'].includes(String(data.platform)) ||
        !['x64', 'arm64', 'ia32'].includes(String(data.arch))
      )
        return
      entry.platform = String(data.platform)
      entry.arch = String(data.arch)
    }
    try {
      mkdirSync(this.directory, { recursive: true, mode: 0o700 })
      const path = join(this.directory, 'diagnostic.jsonl')
      const line = JSON.stringify(entry) + '\n'
      let size = 0
      try {
        size = statSync(path).size
      } catch (error) {
        if ((error as NodeJS.ErrnoException).code !== 'ENOENT') throw error
      }
      if (size + Buffer.byteLength(line) > this.limit) {
        rmSync(join(this.directory, 'diagnostic.2.jsonl'), { force: true })
        const previous = join(this.directory, 'diagnostic.1.jsonl')
        try {
          renameSync(previous, join(this.directory, 'diagnostic.2.jsonl'))
        } catch (error) {
          if ((error as NodeJS.ErrnoException).code !== 'ENOENT') throw error
        }
        renameSync(path, previous)
      }
      appendFileSync(path, line, { mode: 0o600 })
    } catch {
      this.disabled = true
      console.error('SCREEN_LOG_UNAVAILABLE')
    }
  }
}