import { Type } from "@sinclair/typebox";
import type { ExtensionAPI } from "../_shared/pi-api.js";
import { errorResult, getCommandText, setTextWidget } from "../_shared/pi-api.js";
import { validateParams } from "../_shared/validation.js";

const PlanModeParams = Type.Object({
  action: Type.Union([Type.Literal("on"), Type.Literal("off"), Type.Literal("status"), Type.Literal("execute")], { description: "Plan mode action" }),
  planText: Type.Optional(Type.String({ description: "Plan text to extract todos from", maxLength: 20_000 })),
});

export default function plan(pi: ExtensionAPI): void {
  pi.registerTool({
    name: "planMode",
    description: "Legacy alias for local plan mode. Fails closed until OMP plan mode is ported.",
    parameters: PlanModeParams,
    async execute(_toolCallId, params) {
      const valid = validateParams(PlanModeParams, params);
      if (!valid.ok) return valid.result;
      return planModeNotPorted(valid.value.action, "planMode");
    },
  });

  pi.registerCommand("plan", {
    description: "Show fail-closed OMP plan mode status until the native runtime is ported.",
    handler: async (args, ctx) => {
      const [action = "status"] = getCommandText(args).trim().split(/\s+/);
      const result = planModeNotPorted(asPlanAction(action), "plan-command");
      setTextWidget(ctx, "plan", result.content[0]?.type === "text" ? result.content[0].text : "plan mode is not available");
    },
  });

  pi.registerCommand("todos", {
    description: "Show fail-closed OMP plan todo status until the native runtime is ported.",
    handler: async (_args, ctx) => {
      const result = planModeNotPorted("status", "todos-command");
      setTextWidget(ctx, "todos", result.content[0]?.type === "text" ? result.content[0].text : "plan todos are not available");
    },
  });
}

function asPlanAction(action: string): "on" | "off" | "status" | "execute" {
  if (action === "on" || action === "off" || action === "execute") return action;
  return "status";
}

function planModeNotPorted(action: "on" | "off" | "status" | "execute", requestedSurface: "planMode" | "plan-command" | "todos-command" = "planMode") {
  return errorResult(
    [
      "Plan mode is disabled in miloc-pi.",
      "OMP plan mode is the source truth for read-only planning, plan-file writes, hidden `resolve` approval, model/tool restoration, status-line state, and session resume.",
      "This extension does not block tools or inject hidden plan context until OMP plan mode is ported here.",
    ].join("\n"),
    {
      owner: "omp-plan-mode",
      ported: false,
      requestedSurface,
      action,
      ompSources: [
        "packages/coding-agent/src/modes/interactive-mode.ts",
        "packages/coding-agent/src/plan-mode/state.ts",
        "packages/coding-agent/src/plan-mode/approved-plan.ts",
        "packages/coding-agent/src/tools/plan-mode-guard.ts",
        "packages/coding-agent/src/prompts/system/plan-mode-active.md",
        "packages/coding-agent/src/prompts/system/plan-mode-approved.md",
        "packages/coding-agent/src/prompts/tools/resolve.md",
        "packages/coding-agent/src/slash-commands/builtin-registry.ts",
      ],
    },
  );
}