import { Client } from '@open-rpc/client-js'
import { ObservableV2 } from 'lib0/observable'
import { uuidv4 } from 'lib0/random'
import { SHA3 } from 'sha3'
import type {
  Checksum,
  ContextId,
  ExecutionEnvironment,
  ExpressionId,
  FileEdit,
  FileSystemObject,
  Notifications,
  Path,
  RegisterOptions,
  StackItem,
  TextFileContents,
  VisualizationConfiguration,
  response,
} from './languageServerTypes'
import type { Uuid } from './yjsModel'

const DEBUG_LOG_RPC = false
const RPC_TIMEOUT_MS = 10000

class RpcError extends Error {
  cause: Error
  request: string
  params: object
  constructor(inner: Error, request: string, params: object) {
    super(`Language server request failed.`)
    this.cause = inner
    this.request = request
    this.params = params
  }
}

/** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md) */
export class LanguageServer extends ObservableV2<Notifications> {
  client: Client
  handlers: Map<string, Set<(...params: any[]) => void>>

  constructor(client: Client) {
    super()
    this.client = client
    this.handlers = new Map()

    client.onNotification((notification) => {
      this.emit(notification.method as keyof Notifications, [notification.params])
    })
  }

  // The "magic bag of holding" generic that is only present in the return type is UNSOUND.
  // However, it is SAFE, as the return type of the API is statically known.
  private async request<T>(method: string, params: object): Promise<T> {
    const uuid = uuidv4()
    const now = performance.now()
    try {
      if (DEBUG_LOG_RPC) {
        console.log(`LS [${uuid}] ${method}:`)
        console.dir(params)
      }
      return await this.client.request({ method, params }, RPC_TIMEOUT_MS)
    } catch (e) {
      if (e instanceof Error) {
        throw new RpcError(e, method, params)
      }
      throw e
    } finally {
      if (DEBUG_LOG_RPC) {
        console.log(`LS [${uuid}] ${method} took ${performance.now() - now}ms`)
      }
    }
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#capabilityacquire) */
  acquireCapability(method: string, registerOptions: RegisterOptions): Promise<void> {
    return this.request('capability/acquire', { method, registerOptions })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filereceivestreeupdates) */
  acquireReceivesTreeUpdates(path: Path): Promise<void> {
    return this.acquireCapability('file/receivesTreeUpdates', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#sessioninitprotocolconnection) */
  initProtocolConnection(clientId: Uuid): Promise<response.InitProtocolConnection> {
    return this.request('session/initProtocolConnection', { clientId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#textopenfile) */
  openTextFile(path: Path): Promise<response.OpenTextFile> {
    return this.request('text/openFile', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#textclosefile) */
  closeTextFile(path: Path): Promise<void> {
    return this.request('text/closeFile', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#textsave) */
  saveTextFile(path: Path, currentVersion: Checksum): Promise<void> {
    return this.request('text/save', { path, currentVersion })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#textapplyedit) */
  applyEdit(edit: FileEdit, execute: boolean): Promise<void> {
    return this.request('text/applyEdit', { edit, execute })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filewrite) */
  writeFile(path: Path, contents: TextFileContents): Promise<void> {
    return this.request('file/write', { path, contents })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#fileread) */
  readFile(path: Path): Promise<response.FileContents> {
    return this.request('file/read', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filecreate) */
  createFile(object: FileSystemObject): Promise<void> {
    return this.request('file/create', { object })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filedelete) */
  deleteFile(path: Path): Promise<void> {
    return this.request('file/delete', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filecopy) */
  copyFile(from: Path, to: Path): Promise<void> {
    return this.request('file/copy', { from, to })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filemove) */
  moveFile(from: Path, to: Path): Promise<void> {
    return this.request('file/move', { from, to })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#fileexists) */
  fileExists(path: Path): Promise<response.FileExists> {
    return this.request('file/exists', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filetree) */
  fileTree(path: Path, depth?: number): Promise<response.FileTree> {
    return this.request('file/tree', { path, depth })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filelist) */
  listFiles(path: Path): Promise<response.FileList> {
    return this.request('file/list', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#fileinfo) */
  fileInfo(path: Path): Promise<response.FileInfo> {
    return this.request('file/info', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filechecksum) */
  fileChecksum(path: Path): Promise<response.FileChecksum> {
    return this.request('file/checksum', { path })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#vcsinit) */
  vcsInit(root: Path): Promise<void> {
    return this.request('vcs/init', { root })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#vcssave) */
  vcsSave(root: Path, name?: string): Promise<response.VCSCommit> {
    return this.request('vcs/save', { root, name })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#vcsstatus) */
  vcsStatus(root: Path): Promise<response.VCSStatus> {
    return this.request('vcs/status', { root })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#vcsrestore) */
  vcsRestore(root: Path, commitId?: string): Promise<response.VCSChanges> {
    return this.request('vcs/restore', { root, commitId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#vcslist) */
  vcsList(root: Path, limit?: number): Promise<response.VCSSaves> {
    return this.request('vcs/list', { root, limit })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextcreate) */
  createExecutionContext(contextId?: ContextId): Promise<response.ExecutionContext> {
    return this.request('executionContext/create', { contextId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextdestroy) */
  destroyExecutionContext(contextId: ContextId): Promise<void> {
    return this.request('executionContext/destroy', { contextId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextfork) */
  forkExecutionContext(contextId: ContextId): Promise<response.ExecutionContext> {
    return this.request('executionContext/fork', { contextId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextpush) */
  pushExecutionContextItem(contextId: ContextId, stackItem: StackItem): Promise<void> {
    return this.request('executionContext/push', { contextId, stackItem })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextpop) */
  popExecutionContextItem(contextId: ContextId): Promise<void> {
    return this.request('executionContext/pop', { contextId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextrecompute) */
  recomputeExecutionContext(
    contextId: ContextId,
    invalidatedExpressions?: 'all' | string[],
    executionEnvironment?: ExecutionEnvironment,
  ): Promise<void> {
    return this.request('executionContext/recompute', {
      contextId,
      invalidatedExpressions,
      executionEnvironment,
    })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextinterrupt) */
  interruptExecutionContext(contextId: ContextId): Promise<void> {
    return this.request('executionContext/interrupt', { contextId })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextsetexecutionenvironment) */
  setExecutionEnvironment(
    contextId: ContextId,
    executionEnvironment?: ExecutionEnvironment,
  ): Promise<void> {
    return this.request('executionContext/setExecutionEnvironment', {
      contextId,
      executionEnvironment,
    })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextexecuteexpression) */
  executeExpression(
    visualizationId: Uuid,
    expressionId: ExpressionId,
    visualizationConfig: VisualizationConfiguration,
  ): Promise<void> {
    return this.request('executionContext/interrupt', {
      visualizationId,
      expressionId,
      visualizationConfig,
    })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextattachvisualization) */
  attachVisualization(
    visualizationId: Uuid,
    expressionId: ExpressionId,
    visualizationConfig: VisualizationConfiguration,
  ): Promise<void> {
    return this.request('executionContext/attachVisualization', {
      visualizationId,
      expressionId,
      visualizationConfig,
    })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextdetachvisualization) */
  detachVisualization(
    visualizationId: Uuid,
    expressionId: ExpressionId,
    executionContextId: ContextId,
  ): Promise<void> {
    return this.request('executionContext/detachVisualization', {
      visualizationId,
      expressionId,
      executionContextId,
    })
  }

  /** [Documentation](https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#executioncontextmodifyvisualization) */
  modifyVisualization(
    visualizationId: Uuid,
    visualizationConfig: VisualizationConfiguration,
  ): Promise<void> {
    return this.request('executionContext/modifyVisualization', {
      visualizationId,
      visualizationConfig,
    })
  }

  dispose() {
    this.client.close()
  }
}

export function computeTextChecksum(text: string): Checksum {
  return new SHA3(224).update(text).digest('hex') as Checksum
}