import type { BackendEvent, BackendTurnResult, CommandRecord, RunRecord } from "../common/types.js";
import { CodexStdioBackendSession, runCodexStdioTurn, type CodexStdioTurnOptions } from "./codex-stdio.js";
import { backendProfileSpec } from "../common/backend-profiles.js";

export interface BackendAdapterOptions {
  codexCommand?: string;
  codexArgs?: string[];
  codexHome?: string;
  workspacePath?: string;
  abortSignal?: AbortSignal;
  onEvent?: (event: BackendEvent) => void | Promise<void>;
  env?: NodeJS.ProcessEnv;
}

export interface BackendSession {
  runTurn(run: RunRecord, command: CommandRecord, options?: BackendAdapterOptions): Promise<BackendTurnResult>;
  close(): Promise<BackendTurnResult["events"]>;
}

export async function runBackendTurn(run: RunRecord, command: CommandRecord, options: BackendAdapterOptions = {}): Promise<BackendTurnResult> {
  const spec = backendProfileSpec(run.backendProfile);
  if (!spec || spec.backendKind !== "codex-app-server-stdio") {
    return { terminalStatus: "failed", failureKind: "backend-failed", failureMessage: `unsupported backendProfile ${run.backendProfile}`, events: [{ type: "error", payload: { failureKind: "backend-failed", backendProfile: run.backendProfile } }] };
  }
  return runCodexStdioTurn(backendTurnOptions(run, command, options));
}

export function createBackendSession(run: RunRecord, options: BackendAdapterOptions = {}): BackendSession | null {
  const spec = backendProfileSpec(run.backendProfile);
  if (!spec || spec.backendKind !== "codex-app-server-stdio") return null;
  const session = new CodexStdioBackendSession();
  return {
    runTurn: async (nextRun, command, turnOptions = {}) => session.runTurn(backendTurnOptions(nextRun, command, { ...options, ...turnOptions })),
    close: async () => session.close(),
  };
}

export function backendTurnOptions(run: RunRecord, command: CommandRecord, options: BackendAdapterOptions = {}): CodexStdioTurnOptions {
  const prompt = typeof command.payload.prompt === "string" ? command.payload.prompt : JSON.stringify(command.payload);
  const turnOptions: CodexStdioTurnOptions = {
    backendProfile: run.backendProfile,
    prompt,
    cwd: options.workspacePath ?? (typeof run.workspaceRef.path === "string" ? run.workspaceRef.path : process.cwd()),
    approvalPolicy: run.executionPolicy.approval,
    sandbox: run.executionPolicy.sandbox,
    timeoutMs: run.executionPolicy.timeoutMs,
  };
  if (typeof command.payload.model === "string") turnOptions.model = command.payload.model;
  if (typeof command.payload.threadId === "string") turnOptions.threadId = command.payload.threadId;
  else if (typeof run.sessionRef?.threadId === "string") turnOptions.threadId = run.sessionRef.threadId;
  if (options.codexCommand) turnOptions.command = options.codexCommand;
  if (options.codexArgs) turnOptions.args = options.codexArgs;
  if (options.env) turnOptions.env = options.env;
  if (options.codexHome) turnOptions.codexHome = options.codexHome;
  if (options.abortSignal) turnOptions.abortSignal = options.abortSignal;
  if (options.onEvent) turnOptions.onEvent = options.onEvent;
  return turnOptions;
}