import type { ComponentType, ReactNode } from "react";

export interface ActivateContext {
  pluginId: string;
  logger: PluginLogger;
  subscriptions: CommandDisposable[];
  commands?: CommandRegistry;
  layouts?: LayoutRegistry;
  storage?: PluginStorage;
  /**
   * Stable public service facade for plugins that need workspace, background
   * task, or terminal operations. This intentionally does not expose IdeA's
   * internal runtime/gateway objects.
   */
  services?: PluginServices;
}

export interface IdeAPluginModule {
  activate(ctx: ActivateContext): void | Promise<void>;
  deactivate?(): void | Promise<void>;
}

export interface PluginLogger {
  debug(message: string, ...args: unknown[]): void;
  info(message: string, ...args: unknown[]): void;
  warn(message: string, ...args: unknown[]): void;
  error(message: string, ...args: unknown[]): void;
}

export type CommandHandler = (...args: unknown[]) => unknown | Promise<unknown>;

export interface CommandRegistry {
  registerCommand(commandId: string, handler: CommandHandler): CommandDisposable;
}

export interface CommandDisposable {
  dispose(): void;
}

export interface PluginStorage {
  /**
   * Plugin-owned persistent state. Use this for internal counters, flags,
   * preferences and caches that should not be written into the user's project.
   */
  get<T = unknown>(key: string): Promise<T | undefined>;
  set<T = unknown>(key: string, value: T): Promise<void>;
  delete(key: string): Promise<void>;
}

export type PluginLayoutState = JsonValue | undefined;
export type PluginLayoutAvailability = "available";
export type PluginLayoutRenderResult = ReactNode;

export interface PluginLayoutProps<TState extends PluginLayoutState = PluginLayoutState> {
  /** Project currently hosting this layout cell. */
  projectId: string;
  /** Stable layout node id for this cell instance. */
  nodeId: string;
  /** Layout contribution type declared in `idea-plugin.json`. */
  layoutType: string;
  /** Opaque JSON-serializable state persisted by the host for this cell. */
  state: TState;
  /** Replaces the opaque state for this cell. Values must be JSON-serializable. */
  setState(next: TState): void;
  /** Present layouts are only mounted when available; fallback UI is host-owned. */
  availability: PluginLayoutAvailability;
}

export type PluginLayoutComponent<TState extends PluginLayoutState = PluginLayoutState> =
  ComponentType<PluginLayoutProps<TState>>;

export interface PluginLayoutDefinition<TState extends PluginLayoutState = PluginLayoutState> {
  /** Must match a layout `type` declared in this plugin's manifest. */
  type: string;
  component: PluginLayoutComponent<TState>;
}

export interface LayoutRegistry {
  register<TState extends PluginLayoutState = PluginLayoutState>(
    definition: PluginLayoutDefinition<TState>,
  ): CommandDisposable;
}

export interface PluginServices {
  workspace: WorkspaceService;
  tasks: BackgroundTaskService;
  tooling: ToolingService;
  events: EventService;
  config: ConfigDocumentService;
  terminal: TerminalService;
  windows: WindowService;
}

export interface WorkspaceProject {
  id: string;
  name: string;
  root: string;
}

export interface WorkspaceService {
  /** Returns the currently focused project, or null when no project is active. */
  getCurrentProject(): Promise<WorkspaceProject | null>;
  /** Returns the root path for the given project or for the current project. */
  getProjectRoot(projectId?: string): Promise<string>;
  /** Reads IdeA's shared project context for the given or current project. */
  readProjectContext(projectId?: string): Promise<string>;
  /** Updates IdeA's shared project context for the given or current project. */
  updateProjectContext(content: string, projectId?: string): Promise<void>;
  /**
   * Resolves and normalizes a plugin-visible path under the project root.
   * Rejects absolute paths, `..`, empty segments and other paths the host
   * considers outside the workspace sandbox.
   */
  resolvePath(path: string, projectId?: string): Promise<WorkspaceResolvedPath>;
  /** Reads a UTF-8 text file under the project root. */
  readTextFile(path: string, projectId?: string): Promise<WorkspaceTextFile>;
  /** Reads raw bytes from a file under the project root. */
  readBinaryFile(path: string, projectId?: string): Promise<WorkspaceBinaryFile>;
  /** Writes UTF-8 text under the project root using the host's controlled write path. */
  writeTextFile(path: string, content: string, projectId?: string): Promise<void>;
  /** Writes raw bytes under the project root using the host's controlled write path. */
  writeBinaryFile(path: string, bytes: Uint8Array, projectId?: string): Promise<void>;
  /** Lists one directory under the project root. Defaults to the workspace root. */
  listDirectory(path?: string, projectId?: string): Promise<WorkspaceDirectoryListing>;
  /**
   * Returns basic metadata. Missing paths resolve to `{ exists: false }`; invalid
   * paths and permission errors reject.
   */
  stat(path: string, projectId?: string): Promise<WorkspaceStat>;
  /**
   * Extension point for host file watching. The MVP SDK reserves the public
   * shape; hosts may reject with a clear not-implemented error until #127 lands.
   * Plugins must treat watch setup as best-effort and non-fatal.
   */
  watch(path: string, handler: WorkspaceWatchHandler, projectId?: string): Promise<WorkspaceWatch>;
  /** Queries a bounded, generic project structure read model. */
  queryStructure(query?: WorkspaceStructureQuery): Promise<ProjectStructure>;
}

export interface WorkspaceResolvedPath {
  projectId: string;
  root: string;
  path: string;
}

export interface WorkspaceTextFile {
  path: string;
  content: string;
}

export interface WorkspaceBinaryFile {
  path: string;
  bytes: Uint8Array;
}

export interface WorkspaceDirEntry {
  name: string;
  path: string;
  isDir: boolean;
}

export interface WorkspaceDirectoryListing {
  path: string;
  entries: WorkspaceDirEntry[];
}

export interface WorkspaceStat {
  path: string;
  exists: boolean;
  isFile: boolean;
  isDir: boolean;
  len: number | null;
}

export interface WorkspaceWatchEvent {
  path: string;
  kind: "created" | "modified" | "deleted" | "renamed" | "unknown";
  operation: string;
  projectId: string;
}

export type WorkspaceWatchHandler = (event: WorkspaceWatchEvent) => void;

export interface WorkspaceWatch {
  dispose(): void;
}

export interface WorkspaceStructureQuery {
  projectId?: string;
  path?: string;
  maxDepth?: number;
  maxEntries?: number;
}

export type ProjectStructureEntryKind = "file" | "directory";

export interface ProjectStructureEntry {
  path: string;
  name: string;
  kind: ProjectStructureEntryKind;
}

export interface ProjectConvention {
  id: string;
  markerPath: string;
}

export interface ProjectModule {
  path: string;
  markerPath: string;
  conventionId: string;
}

export interface ProjectStructure {
  projectId: string;
  rootPath: string;
  entries: ProjectStructureEntry[];
  conventions: ProjectConvention[];
  modules: ProjectModule[];
  truncated: boolean;
}

export interface BackgroundTaskStatus {
  taskId: string;
  /**
   * Agent that owns completion delivery and Work attribution for this task.
   * This is host-assigned for existing tasks and should be treated as an opaque
   * agent id by plugins.
   */
  ownerAgentId: string;
  projectId: string;
  kind: string;
  /**
   * Work read-model status. A skipped plugin command is not a background task
   * and therefore never appears here; skipped commands should be reported by
   * the command handler return value and plugin logs.
   */
  status: "pending" | "running" | "completed" | "failed" | "cancelled" | "delivered";
  exitCode: number | null;
  summary: string | null;
  stdoutTail: string | null;
  stderrTail: string | null;
  updatedAtMs: number;
}

export interface BackgroundTaskOutputAttachment {
  taskId: string;
  scrollback: Uint8Array;
  live: boolean;
  detach(): void;
}

export interface BackgroundTaskRetryResult {
  /** Present when the host reports the replacement task id. */
  taskId?: string;
}

export interface RunCommandTaskOptions {
  /** Project that owns the command workspace. Defaults to the focused project. */
  projectId?: string;
  /**
   * Real agent id used by IdeA Work for ownership, cancellation and completion
   * delivery. Plugins must obtain this from host/plugin state for the workflow
   * they are serving; placeholder ids are only acceptable in isolated examples.
   */
  ownerAgentId: string;
  /** Human-facing label shown in Work. Defaults to the command line. */
  label?: string;
  /** Executable to run. Arguments are passed separately, without shell parsing. */
  command: string;
  /** Arguments passed to the executable. */
  args?: string[];
  /** Relative working directory under the project root. Defaults to the root. */
  cwd?: string;
  /** Extra environment variables for the command. */
  env?: Record<string, string> | Array<[string, string]>;
  /**
   * When true, completion is recorded without waking the owner agent. This does
   * not hide the task from Work/background-task surfaces and does not represent
   * a skipped command. If preconditions fail, return readable command feedback
   * instead of launching a record-only task.
   */
  recordOnly?: boolean;
  /** Optional absolute deadline, epoch milliseconds. */
  deadlineMs?: number;
}

export interface CommandTaskStatus {
  taskId: string;
  /**
   * Agent that owns this command task. The host uses it for correlation,
   * cancellation and completion delivery.
   */
  ownerAgentId: string;
  projectId: string;
  kind: string;
  /**
   * Lifecycle state of a command task that was actually launched. There is no
   * `skipped` state: skipped commands are command-handler feedback, not tasks.
   */
  state: "queued" | "running" | "waiting" | "completed" | "failed" | "cancelled" | "expired";
  exitCode: number | null;
  summary: string | null;
  stdoutTail: string | null;
  stderrTail: string | null;
  createdAtMs: number;
  updatedAtMs: number;
}

export interface ToolRequirement {
  /** Stable id chosen by the plugin for this executable prerequisite. */
  id: string;
  /** Executable name or path to probe. */
  executable: string;
  /** Version/diagnostic arguments. Defaults host-side to `--version`. */
  versionArgs?: string[];
  /** Whether this tool must pass for the whole diagnostic to be ok. */
  required?: boolean;
  /** Extra environment variables for this probe. */
  env?: Record<string, string> | Array<[string, string]>;
}

export interface EnvRequirement {
  /** Environment variable name. */
  name: string;
  /** Whether the variable must be present and match. */
  required?: boolean;
  /** Optional exact expected value. */
  equals?: string;
}

export interface FileRequirement {
  /** Relative workspace path. */
  path: string;
  /** Whether the path must exist and match `kind`. */
  required?: boolean;
  /** Expected workspace path kind. */
  kind?: "file" | "directory" | "any";
}

export interface ToolchainDiagnosticRequest {
  /** Project to inspect. Defaults to the focused project. */
  projectId?: string;
  /** Relative working directory under the project root. Defaults to the root. */
  cwd?: string;
  /** Executable probes to run. */
  tools?: ToolRequirement[];
  /** Environment variable prerequisites to inspect. */
  env?: EnvRequirement[];
  /** Workspace file prerequisites to validate. */
  files?: FileRequirement[];
}

export interface ToolchainDiagnostic {
  projectId: string;
  cwd: string;
  ok: boolean;
  tools: ToolDiagnostic[];
  env: EnvDiagnostic[];
  files: FileDiagnostic[];
  messages: DiagnosticMessage[];
}

export interface ToolDiagnostic {
  id: string;
  executable: string;
  present: boolean;
  ok: boolean;
  status: "ok" | "failed" | "missing";
  required: boolean;
  exitCode: number | null;
  version: string | null;
  stdout: string | null;
  stderr: string | null;
  error: string | null;
}

export interface EnvDiagnostic {
  name: string;
  present: boolean;
  ok: boolean;
  required: boolean;
  value: string | null;
  status: "ok" | "missing" | "mismatch";
}

export interface FileDiagnostic {
  path: string;
  exists: boolean;
  ok: boolean;
  required: boolean;
  kind: "file" | "directory" | "other" | "missing";
  expectedKind: "file" | "directory" | "any" | null;
  len: number | null;
}

export interface DiagnosticMessage {
  level: "info" | "warning" | "error";
  message: string;
}

export interface ToolingService {
  /** Runs generic external-toolchain diagnostics for executables, env and files. */
  diagnose(request: ToolchainDiagnosticRequest): Promise<ToolchainDiagnostic>;
}

export type PublicEventType = "workspaceFileChanged" | "backgroundTaskChanged";

export type PublicEvent = WorkspaceFileChangedEvent | BackgroundTaskChangedEvent;

export interface WorkspaceFileChangedEvent {
  type: "workspaceFileChanged";
  sequence: number;
  occurredAtMs: number;
  projectId: string;
  path: string;
  operation: string;
}

export interface BackgroundTaskChangedEvent {
  type: "backgroundTaskChanged";
  sequence: number;
  occurredAtMs: number;
  projectId: string;
  taskId: string;
  ownerAgentId: string;
  state: string;
}

export interface EventSubscribeOptions {
  /** Project to observe. Defaults to the focused project. */
  projectId?: string;
  /** Public event types to retain. Empty/omitted means every supported event. */
  eventTypes?: PublicEventType[];
  /** Per-subscription retained capacity. Host clamps to its supported bounds. */
  capacity?: number;
  /** Polling cadence used by the runtime facade. Defaults to 1000 ms. */
  pollIntervalMs?: number;
  /** Maximum events drained per poll. Host clamps to its supported bounds. */
  maxEventsPerPoll?: number;
  /** Called when the host reports dropped retained events for this subscription. */
  onDropped?: (count: number) => void;
}

export interface EventSubscription {
  readonly subscriptionId: string;
  readonly projectId: string;
  readonly eventTypes: PublicEventType[];
  readonly retention: string;
  dispose(): void;
}

export type EventHandler = (event: PublicEvent) => void;

export interface EventService {
  /** Subscribes to stable, best-effort bounded public host/project events. */
  subscribe(options: EventSubscribeOptions, handler: EventHandler): Promise<EventSubscription>;
}

export type JsonValue =
  | null
  | boolean
  | number
  | string
  | JsonValue[]
  | { [key: string]: JsonValue };

export type ConfigDocumentFormat = "json";
export type ConfigUpdateMode = "mergePatch" | "replace";

export interface ConfigDocumentReadOptions {
  /** Project that owns the config document. Defaults to the focused project. */
  projectId?: string;
  /** Relative path under the project root. */
  path: string;
  /** Explicit format. Omit to infer from extension. First lot supports only `json`. */
  format?: ConfigDocumentFormat;
}

export interface ConfigDocumentUpdateOptions extends ConfigDocumentReadOptions {
  /** Update mode. Defaults host-side to `mergePatch`. */
  mode?: ConfigUpdateMode;
  /** Replacement value or JSON merge patch. */
  value: JsonValue;
}

export interface ConfigDocument<T extends JsonValue = JsonValue> {
  projectId: string;
  path: string;
  format: ConfigDocumentFormat;
  value: T;
}

export interface ConfigDocumentWriteResult {
  projectId: string;
  path: string;
  format: ConfigDocumentFormat;
  mode: ConfigUpdateMode;
  bytesWritten: number;
}

export interface ConfigDocumentService {
  /** Reads and parses a structured config document. First lot supports JSON only. */
  readDocument<T extends JsonValue = JsonValue>(
    options: ConfigDocumentReadOptions,
  ): Promise<ConfigDocument<T>>;
  /** Writes a full replacement or JSON merge patch. First lot supports JSON only. */
  updateDocument(options: ConfigDocumentUpdateOptions): Promise<ConfigDocumentWriteResult>;
}

export interface BackgroundTaskService {
  /**
   * Launches a non-interactive command as a first-class IdeA background task.
   *
   * Call this only after command preconditions are satisfied. The returned
   * `CommandTaskStatus` means a task exists and can be inspected through command
   * status APIs and Work/background-task surfaces. A plugin command that decides
   * not to launch work should return readable command feedback, for example
   * `{ status: "skipped", reason, message }`, and should not call `runCommand()`.
   */
  runCommand(options: RunCommandTaskOptions): Promise<CommandTaskStatus>;
  /** Reads one command task directly from the host task store. */
  getCommandStatus(taskId: string): Promise<CommandTaskStatus | null>;
  /** Lists background tasks visible in the project work-state read model. */
  list(projectId?: string): Promise<BackgroundTaskStatus[]>;
  /** Reads one task status from the project work-state read model. */
  getStatus(taskId: string, projectId?: string): Promise<BackgroundTaskStatus | null>;
  /** Attaches to retained/live output for a task. */
  attachOutput(
    taskId: string,
    onData: (bytes: Uint8Array) => void,
  ): Promise<BackgroundTaskOutputAttachment>;
  /** Cancels a pending/running task. */
  cancel(taskId: string): Promise<void>;
  /** Retries a failed/cancelled task; future hosts may return the new task id. */
  retry(taskId: string): Promise<BackgroundTaskRetryResult>;
}

export interface TerminalOpenOptions {
  cwd?: string;
  rows?: number;
  cols?: number;
  onData?: (bytes: Uint8Array) => void;
}

export interface TerminalReattachOptions {
  onData?: (bytes: Uint8Array) => void;
}

export interface TerminalSession {
  readonly sessionId: string;
  write(data: Uint8Array): Promise<void>;
  resize(rows: number, cols: number): Promise<void>;
  detach(): void;
  close(): Promise<void>;
}

export interface TerminalReattachResult {
  session: TerminalSession;
  scrollback: Uint8Array;
}

export interface TerminalService {
  /**
   * Opens a shell PTY in the requested/current project directory. This MVP is a
   * terminal control surface, not a command runner; use tasks for build/test
   * commands that should be tracked in the Work panel.
   */
  open(options?: TerminalOpenOptions): Promise<TerminalSession>;
  /** Reattaches to an already-running PTY and returns retained scrollback. */
  reattach(sessionId: string, options?: TerminalReattachOptions): Promise<TerminalReattachResult>;
  /** Kills a PTY by id. */
  close(sessionId: string): Promise<void>;
}

export interface OpenPluginWindowOptions {
  /** Layout `type` declared by this plugin in `contributes.layouts`. */
  layoutType: string;
  /** Initial opaque state copied into the detached window surface. */
  state?: JsonValue;
}

export interface PluginWindow {
  label: string;
  url: string;
  alreadyOpen: boolean;
  providerPluginDisplayName: string;
  layoutLabel: string;
  surface: {
    pluginId: string;
    layoutType: string;
    state: JsonValue;
  };
}

export interface WindowService {
  /**
   * Opens or focuses a detached IdeA OS window hosting one of this plugin's
   * declared layout contributions. The host rejects layout ids absent from this
   * plugin's manifest.
   */
  open(options: OpenPluginWindowOptions): Promise<PluginWindow>;
}