/** Same-origin client controls for durable managed-editor recovery. */

import { editorControlUrl, type EditorLocale } from './editor-bridge.js'

export interface EditorRecoverySummary {
  id: string
  capturedAt: number
  bytes: number
  sourceName: string
  sourceChangedSinceCapture: boolean
  cacheLabel: string
}

export interface EditorRecoveryLaunch {
  sessionId: string
  recoveryUrl?: string
  recovery?: EditorRecoverySummary
}

function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === 'object' && value !== null && !Array.isArray(value)
}

export function editorRecoverySummaryOf(value: unknown): EditorRecoverySummary | undefined {
  if (!isRecord(value)) return undefined
  if (
    typeof value.id !== 'string' || !/^[A-Za-z0-9_-]{43}$/.test(value.id)
    || typeof value.capturedAt !== 'number' || !Number.isSafeInteger(value.capturedAt) || value.capturedAt <= 0
    || typeof value.bytes !== 'number' || !Number.isSafeInteger(value.bytes) || value.bytes <= 0
    || typeof value.sourceName !== 'string' || value.sourceName.length <= 0 || value.sourceName.length > 512
    || typeof value.sourceChangedSinceCapture !== 'boolean'
    || typeof value.cacheLabel !== 'string' || !value.cacheLabel.startsWith('dsh-openpencil/recovery/')
  ) return undefined
  return value as unknown as EditorRecoverySummary
}

export function editorRecoveryItemUrl(launch: EditorRecoveryLaunch, recoveryId: string): string {
  if (launch.recoveryUrl === undefined) throw new Error('OpenPencil recovery control is unavailable')
  if (!/^[A-Za-z0-9_-]{43}$/.test(recoveryId)) throw new Error('OpenPencil recovery id is invalid')
  return `${editorControlUrl(launch.recoveryUrl)}/${recoveryId}`
}

async function checkedJson(response: Response, action: string): Promise<unknown> {
  if (!response.ok) throw new Error(`${action} failed (${response.status})`)
  return response.json()
}

/** Capture the authoritative daemon document; never serializes the iframe from React. */
export async function captureManagedEditorRecovery(
  launch: EditorRecoveryLaunch,
  fetcher: typeof fetch = fetch,
): Promise<EditorRecoverySummary | undefined> {
  if (launch.recoveryUrl === undefined) return undefined
  const value = await checkedJson(await fetcher(editorControlUrl(launch.recoveryUrl), {
    method: 'POST',
    credentials: 'same-origin',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ sessionId: launch.sessionId }),
    keepalive: true,
  }), 'OpenPencil recovery capture')
  if (!isRecord(value) || value.ok !== true) throw new Error('OpenPencil recovery capture returned an invalid result')
  if (value.recovery === null) return undefined
  const recovery = editorRecoverySummaryOf(value.recovery)
  if (recovery === undefined) throw new Error('OpenPencil recovery capture omitted recovery metadata')
  return recovery
}

/** Explicitly restore into the live daemon. The user must still press Save to update `.op`. */
export async function restoreManagedEditorRecovery(
  launch: EditorRecoveryLaunch,
  recovery: EditorRecoverySummary,
  fetcher: typeof fetch = fetch,
): Promise<string> {
  const value = await checkedJson(await fetcher(editorRecoveryItemUrl(launch, recovery.id), {
    method: 'POST', credentials: 'same-origin',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ sessionId: launch.sessionId }),
  }), 'OpenPencil recovery restore')
  if (!isRecord(value) || value.ok !== true || typeof value.docJson !== 'string') {
    throw new Error('OpenPencil recovery restore returned an invalid result')
  }
  return value.docJson
}

export async function discardManagedEditorRecovery(
  launch: EditorRecoveryLaunch,
  recovery: EditorRecoverySummary,
  fetcher: typeof fetch = fetch,
): Promise<void> {
  const value = await checkedJson(await fetcher(editorRecoveryItemUrl(launch, recovery.id), {
    method: 'DELETE', credentials: 'same-origin',
    headers: { 'content-type': 'application/json' },
    body: JSON.stringify({ sessionId: launch.sessionId }),
  }), 'OpenPencil recovery discard')
  if (!isRecord(value) || value.ok !== true) throw new Error('OpenPencil recovery discard returned an invalid result')
}

export interface EditorRecoveryCopy {
  available: (sourceName: string) => string
  conflict: (sourceName: string) => string
}

const COPY: Record<EditorLocale, EditorRecoveryCopy> = {
  'zh-CN': {
    available: sourceName => `发现 ${sourceName} 的未保存恢复稿。是否恢复？恢复后仍需点击“保存”才会写入源文件。`,
    conflict: sourceName => `发现 ${sourceName} 的未保存恢复稿，但源文件之后已被修改。仍要将恢复稿载入画布吗？恢复不会自动覆盖源文件。`,
  },
  'en-US': {
    available: sourceName => `An unsaved recovery draft for ${sourceName} is available. Restore it? You must still select Save to write the source file.`,
    conflict: sourceName => `An unsaved recovery draft for ${sourceName} is available, but the source changed later. Load the draft into the canvas anyway? Recovery will not overwrite the source automatically.`,
  },
}

export function editorRecoveryCopy(locale: EditorLocale): EditorRecoveryCopy {
  return COPY[locale]
}