import type { ExtensionAPI, ExtensionCommandContext } from "@earendil-works/pi-coding-agent";
import type { AutocompleteItem } from "@earendil-works/pi-tui";
import type { CorridorRuntime } from "../application/corridor-runtime.ts";
import {
  ensureHub,
  readHubMeta,
  sessionViewerUrl,
  shouldAutoOpenBrowser,
} from "../application/hub-client.ts";

const SUBCOMMANDS = ["status", "doctor", "viewer"] as const;

function emit(
  ctx: ExtensionCommandContext,
  message: string,
  type: "info" | "warning" | "error" = "info",
): void {
  if (ctx.mode === "print") {
    console.log(message);
    return;
  }
  if (ctx.mode === "json") {
    process.stderr.write(`${message}\n`);
    return;
  }
  ctx.ui.notify(message, type);
}

function statusText(runtime: CorridorRuntime): string {
  const view = runtime.getView();
  return [
    `North Star: ${view.rootIntent}`,
    `Revision: ${view.revision}`,
    `Stack depth: ${view.stack.length}`,
    `Current action: ${view.now}`,
    `Position: ${view.position.mode}`,
    `Snapshot: ${view.snapshotHash}`,
  ].join("\n");
}

function viewerGuidance(runtime: CorridorRuntime, hub?: ReturnType<typeof ensureHub>): string {
  const sessionId = runtime.getSessionId();
  const meta = readHubMeta();
  const baseUrl = hub?.baseUrl ?? meta?.baseUrl;
  const url = baseUrl ? sessionViewerUrl(baseUrl, sessionId) : undefined;
  return [
    "Intent Petri visualization lives in the local web hub (multi-session).",
    url ? `Open: ${url}` : "Start hub: intent-petri-hub ensure --open",
    "List all sessions: open the hub root URL (default http://127.0.0.1:7731/)",
    `Projection: ${runtime.getProjectionPath() ?? "not initialized"}`,
    "Herdr terminal graph plugin is deprecated and no longer the primary UI.",
  ].join("\n");
}

function hubOptions(runtime: CorridorRuntime, extra: { open?: boolean } = {}) {
  const sessionId = runtime.getSessionId();
  return {
    ...(sessionId ? { sessionId } : {}),
    ...(extra.open ? { open: true as const } : extra.open === false ? { open: false as const } : {}),
  };
}

export function registerCommands(pi: ExtensionAPI, runtime: CorridorRuntime): void {
  pi.registerCommand("intent-petri", {
    description: "Inspect Intent Petri state or open the local web hub viewer",
    getArgumentCompletions(prefix): AutocompleteItem[] | null {
      const options = SUBCOMMANDS.filter((item) => item.startsWith(prefix)).map((item) => ({ value: item, label: item }));
      return options.length > 0 ? options : null;
    },
    handler: async (args, ctx) => {
      const command = args.trim().toLowerCase();
      if (command === "status") {
        emit(ctx, statusText(runtime));
        return;
      }
      if (command === "doctor") {
        const report = runtime.doctor(ctx);
        const hub = ensureHub(hubOptions(runtime));
        emit(
          ctx,
          [
            `Extension: intent-petri v${report.version}`,
            `Source: ${report.sourceKind} · ${report.sourcePath}`,
            ...(report.installedUserVersion ? [`Installed user npm version: ${report.installedUserVersion}`] : []),
            `Revision: ${report.revision}`,
            `Snapshot: ${report.snapshotHash}`,
            `Branch checkpoints: ${report.branchCheckpoints}`,
            `Migrated schema-1 checkpoints: ${report.migratedBranchCheckpoints}`,
            `Invalid checkpoints skipped: ${report.invalidBranchCheckpoints}`,
            `Stale rollback checkpoints ignored: ${report.ignoredDivergentCheckpoints}`,
            ...report.branchIssues.slice(0, 3).map(
              (issue) => `Checkpoint ${issue.entryId}${issue.revision !== undefined ? ` r${issue.revision}` : ""}: ${issue.reason}`,
            ),
            `Branch hashes: ${report.branchHashVerified ? "verified" : "mismatch"}`,
            `Projection: ${report.projectionPath ?? "not initialized"}`,
            `Projection renderer: ${report.projectionError ? `fallback · ${report.projectionError}` : "healthy"}`,
            `Activity projection: ${report.activityProjectionError ?? "healthy"}`,
            `Web hub: ${hub.ok ? hub.baseUrl ?? "ok" : hub.error ?? "unavailable"}`,
            `SQLite audit: ${report.sqlite ? `${report.sqlite.checkpoints} checkpoint(s) · ${report.sqlite.path}` : "closed"}`,
          ].join("\n"),
          report.branchHashVerified ? "info" : "warning",
        );
        return;
      }
      if (command === "viewer") {
        const hub = ensureHub(hubOptions(runtime, { open: true }));
        emit(
          ctx,
          viewerGuidance(runtime, hub),
          hub.ok ? "info" : "warning",
        );
        return;
      }
      if (command) {
        emit(ctx, "Usage: /intent-petri [status|doctor|viewer]", "error");
        return;
      }
      const hub = ensureHub(hubOptions(runtime, { open: shouldAutoOpenBrowser() }));
      emit(ctx, viewerGuidance(runtime, hub), hub.ok ? "info" : "warning");
    },
  });
}