import type { Result } from "../../result.ts";
import type { FileByteSource } from "../browser-file-storage/file.ts";
import type {
  BrowserDataFailure,
  BrowserDataResult,
  TransferProgress,
} from "../browser-file-storage/shared.ts";

export const RESUMABLE_UPLOAD_PROTOCOL =
  "PRESIGNED_MULTIPART_V1" as const;
export type ResumableUploadProtocol =
  typeof RESUMABLE_UPLOAD_PROTOCOL;

/**
 * Multipart uploads use a bounded part manifest instead of a whole-file
 * ArrayBuffer. The digest is SHA-256 over the canonical ordered part metadata
 * and SHA-256 part digests.
 */
export type UploadFileFingerprint = Readonly<{
  algorithm: "SHA-256-PARTS-V1";
  digestHex: string;
  byteLength: number;
  partSizeBytes: number;
  partCount: number;
}>;

export type UploadPartDescriptor = Readonly<{
  partNumber: number;
  offset: number;
  byteLength: number;
  checksumSha256: string;
}>;

/**
 * A non-authorizing server acknowledgement. It must be opaque, contain no PII,
 * URL or credential, and be accepted only with the exact descriptor binding.
 */
export type UploadPartReceipt = UploadPartDescriptor &
  Readonly<{
    receiptToken: string;
  }>;

export type PartitionDeleteOutcome =
  | Readonly<{ state: "DELETED"; effect: "APPLIED" }>
  | Readonly<{
      state: "PENDING";
      effect: "UNKNOWN";
      reason: "BLOCKED_DEADLINE";
    }>;

export interface UploadRangeReader {
  readonly byteLength: number;
  readRange(input: Readonly<{
    offset: number;
    length: number;
    signal: AbortSignal;
  }>): Promise<BrowserDataResult<Uint8Array>>;
}

/**
 * FILE_BYTE_SOURCE supports existing FileByteSource implementations. It must
 * be replayable for the fingerprint pass and transfer pass. RANGE_READER is
 * preferred for concurrent uploads and OPFS/file-vault range adapters.
 */
export type ResumableUploadSource =
  | Readonly<{
      kind: "FILE_BYTE_SOURCE";
      bytes: FileByteSource;
    }>
  | Readonly<{
      kind: "RANGE_READER";
      reader: UploadRangeReader;
    }>;

export type ResumableUploadRequest = Readonly<{
  /** Opaque, caller-stable operation key. It must not contain a file name. */
  uploadKey: string;
  /** Registry-approved backend purpose identifier, not user-provided text. */
  purpose: string;
  mediaType: string;
  source: ResumableUploadSource;
  signal: AbortSignal;
  onProgress?: (progress: TransferProgress) => void;
}>;

export type QuarantinedUpload = Readonly<{
  state: "QUARANTINED";
  resourceId: string;
  byteLength: number;
  replayed: boolean;
}>;

export type UploadAbortOutcome = Readonly<{
  state: "ABORTED" | "ORPHANED" | "ALREADY_COMPLETED" | "NOT_FOUND";
}>;

export interface ResumableUploadPort {
  upload(
    request: ResumableUploadRequest,
  ): Promise<BrowserDataResult<QuarantinedUpload>>;
  abort(request: Readonly<{
    uploadKey: string;
    signal: AbortSignal;
  }>): Promise<BrowserDataResult<UploadAbortOutcome>>;
}

/**
 * Retry-After is transport metadata used only by the runtime. It is bounded
 * before sleeping and is removed from the application-facing failure.
 */
export type UploadProviderFailure = BrowserDataFailure &
  Readonly<{
    retryAfterMs?: number;
  }>;

export type UploadProviderResult<Value> = Result<
  Value,
  UploadProviderFailure
>;

export type UploadSession = Readonly<{
  protocol: ResumableUploadProtocol;
  sessionId: string;
  requestBindingSha256: string;
  fingerprint: UploadFileFingerprint;
  partSizeBytes: number;
  partCount: number;
  maxConcurrency: number;
  expiresAtEpochMs: number;
}>;

export type ActiveUploadStatus = Readonly<{
  state: "ACTIVE";
  session: UploadSession;
  acceptedParts: readonly UploadPartReceipt[];
}>;

export type UploadSessionStatus =
  | ActiveUploadStatus
  | Readonly<{
      state: "QUARANTINED";
      session: UploadSession;
      resourceId: string;
    }>
  | Readonly<{
      state: "ABORTED" | "EXPIRED" | "NOT_FOUND";
      protocol: ResumableUploadProtocol;
      sessionId: string;
      requestBindingSha256: string;
    }>;

/**
 * The capability value is intentionally generic. The presigned-transfer
 * adapter owns its URL/method/header contract; this port neither duplicates
 * that type nor permits it to enter a durable checkpoint.
 */
export type UploadPartCapability<Capability> = Readonly<{
  capability: Capability;
  uploadBindingSha256: string;
  expiresAtEpochMs: number;
}>;

export interface ResumableUploadControlPlane<Capability> {
  createSession(input: Readonly<{
    protocol: ResumableUploadProtocol;
    uploadKey: string;
    purpose: string;
    mediaType: string;
    requestBindingSha256: string;
    fingerprint: UploadFileFingerprint;
    requestedPartSizeBytes: number;
    requestedMaxConcurrency: number;
    idempotencyKey: string;
    signal: AbortSignal;
  }>): Promise<UploadProviderResult<UploadSession>>;

  getStatus(input: Readonly<{
    protocol: ResumableUploadProtocol;
    sessionId: string;
    requestBindingSha256: string;
    fingerprint: UploadFileFingerprint;
    signal: AbortSignal;
  }>): Promise<UploadProviderResult<UploadSessionStatus>>;

  issuePartCapability(input: Readonly<{
    protocol: ResumableUploadProtocol;
    sessionId: string;
    requestBindingSha256: string;
    uploadBindingSha256: string;
    fingerprint: UploadFileFingerprint;
    mediaType: string;
    part: UploadPartDescriptor;
    idempotencyKey: string;
    signal: AbortSignal;
  }>): Promise<UploadProviderResult<UploadPartCapability<Capability>>>;

  complete(input: Readonly<{
    protocol: ResumableUploadProtocol;
    sessionId: string;
    requestBindingSha256: string;
    fingerprint: UploadFileFingerprint;
    orderedParts: readonly UploadPartReceipt[];
    idempotencyKey: string;
    signal: AbortSignal;
  }>): Promise<UploadProviderResult<Readonly<{
    state: "QUARANTINED";
    protocol: ResumableUploadProtocol;
    sessionId: string;
    requestBindingSha256: string;
    fingerprint: UploadFileFingerprint;
    resourceId: string;
  }>>>;

  abort(input: Readonly<{
    protocol: ResumableUploadProtocol;
    sessionId: string;
    requestBindingSha256: string;
    idempotencyKey: string;
    signal: AbortSignal;
  }>): Promise<UploadProviderResult<Readonly<{
    state: "ABORTED" | "NOT_FOUND" | "EXPIRED" | "ALREADY_COMPLETED";
  }>>>;
}

export interface UploadPartExecutor<Capability> {
  uploadPart(input: Readonly<{
    protocol: ResumableUploadProtocol;
    capability: Capability;
    sessionId: string;
    requestBindingSha256: string;
    uploadBindingSha256: string;
    fingerprint: UploadFileFingerprint;
    mediaType: string;
    part: UploadPartDescriptor;
    bytes: Uint8Array;
    idempotencyKey: string;
    signal: AbortSignal;
  }>): Promise<UploadProviderResult<UploadPartReceipt>>;
}

/**
 * Durable, non-secret recovery state. Implementations must reject any unknown
 * property so a signed URL, authorization header or user metadata cannot be
 * smuggled into persistence.
 */
export type ResumableUploadCheckpoint = Readonly<{
  schemaVersion: 1;
  protocol: ResumableUploadProtocol;
  revision: number;
  state: "ACTIVE" | "ABORT_PENDING";
  uploadKey: string;
  requestBindingSha256: string;
  fingerprint: UploadFileFingerprint;
  sessionId: string;
  sessionExpiresAtEpochMs: number;
  sessionMaxConcurrency: number;
  acceptedParts: readonly UploadPartReceipt[];
  updatedAtEpochMs: number;
}>;

export interface ResumableUploadCheckpointStore {
  read(
    uploadKey: string,
    signal?: AbortSignal,
  ): Promise<BrowserDataResult<ResumableUploadCheckpoint | null>>;
  compareAndSwap(input: Readonly<{
    expectedRevision: number | null;
    checkpoint: ResumableUploadCheckpoint;
    signal?: AbortSignal;
  }>): Promise<BrowserDataResult<ResumableUploadCheckpoint>>;
  remove(input: Readonly<{
    uploadKey: string;
    expectedRevision: number;
    signal?: AbortSignal;
  }>): Promise<BrowserDataResult<void>>;
  close(): void;
}

export interface ResumableUploadCheckpointAdmin {
  /**
   * Account/logout lifecycle operation for this already-bound opaque partition.
   * The adapter closes its connection before deletion and bounds blocked waits.
   */
  /**
   * BT-UP-03. An IndexedDB `deleteDatabase()` request cannot be cancelled once
   * dispatched, so a blocked deadline is not evidence that nothing happened.
   * `PENDING` reports the effect honestly as `UNKNOWN`; only pre-dispatch
   * problems are ordinary failures.
   */
  deletePartition(
    signal?: AbortSignal,
  ): Promise<BrowserDataResult<PartitionDeleteOutcome>>;
}