import type { ExtensionContext } from "@earendil-works/pi-coding-agent";
import { defineMenu, runMenu } from "@narumitw/pi-tui-kit";
import { withBorderedCustomUi } from "@signalridge/pi-ui";
import { type PlanExportDestinationProvider, planExportInputScreen } from "./plan-export-screen.js";

interface MenuLifecycle {
  signal: AbortSignal;
  isCurrent(): boolean;
}

const IMPLEMENTATION_CONTEXT_LINES = [
  "Implement here keeps this planning conversation.",
  "Start fresh transfers only the approved plan to a new session.",
] as const;

interface PlanMenuOptions extends MenuLifecycle {
  statusText: string;
  hasReadyPlan: boolean;
  implementationOutcome(): string;
  getExportDestination: PlanExportDestinationProvider;
  show(): void;
  finalize(): void;
  implementHere(): void | Promise<void>;
  implementFresh(signal: AbortSignal): void | Promise<void>;
  exportPlan(path: string, signal: AbortSignal): Promise<boolean>;
  save(): void;
  stay(): void;
  exit(): void;
}

export async function showPlanModeMenu(ctx: ExtensionContext, options: PlanMenuOptions) {
  type Screen = "main" | "export";
  type Action = "show" | "finalize" | "implement-here" | "implement-fresh" | "export" | "save" | "stay" | "exit";
  const menu = defineMenu<undefined, Screen, Action, ExtensionContext>({
    start: "main",
    screens: {
      main: () => ({
        kind: "actions",
        title: "Plan mode",
        lines: [
          options.statusText,
          ...(options.hasReadyPlan ? [...IMPLEMENTATION_CONTEXT_LINES, options.implementationOutcome()] : []),
        ],
        items: options.hasReadyPlan
          ? [
              { id: "show", label: "Show latest proposed plan", action: "show" },
              {
                id: "implement-here",
                label: "Implement here",
                description: "Continue in this session with the planning conversation.",
                action: "implement-here",
              },
              {
                id: "implement-fresh",
                label: "Start fresh and implement",
                description: "Open a new linked session; transfer only the approved plan.",
                action: "implement-fresh",
                busyLabel: "Starting fresh implementation session…",
              },
              { id: "export", label: "Export plan…", to: "export" },
              { id: "save", label: "Save for later", action: "save" },
              { id: "stay", label: "Stay in Plan mode", action: "stay" },
              { id: "exit", label: "Discard plan and exit", action: "exit" },
            ]
          : [
              { id: "finalize", label: "Request final plan", action: "finalize" },
              { id: "stay", label: "Stay in Plan mode", action: "stay" },
              { id: "exit", label: "Exit Plan mode", action: "exit" },
            ],
        hint: "close",
      }),
      export: () => planExportInputScreen(options.getExportDestination),
    },
    actions: {
      show: async () => {
        options.show();
        return { kind: "close" };
      },
      finalize: async () => {
        options.finalize();
        return { kind: "close" };
      },
      "implement-here": async () => {
        await options.implementHere();
        return { kind: "close" };
      },
      "implement-fresh": async ({ signal }) => {
        await options.implementFresh(signal);
        return { kind: "close" };
      },
      export: async ({ value, signal }) =>
        (await options.exportPlan(value ?? "", signal)) ? { kind: "close" } : { kind: "rejected" },
      save: async () => {
        options.save();
        return { kind: "close" };
      },
      stay: async () => {
        options.stay();
        return { kind: "close" };
      },
      exit: async () => {
        options.exit();
        return { kind: "close" };
      },
    },
  });
  await runMenu(withBorderedCustomUi(ctx), menu, {
    getState: () => undefined,
    signal: options.signal,
    isCurrent: options.isCurrent,
  });
}

interface ReadyPlanMenuOptions extends MenuLifecycle {
  implementationOutcome(): string;
  getExportDestination: PlanExportDestinationProvider;
  implementHere(): void | Promise<void>;
  implementFresh(signal: AbortSignal): void | Promise<void>;
  exportPlan(path: string, signal: AbortSignal): Promise<boolean>;
  save(): void;
  stay(): void;
  exit(): void;
}

export async function showReadyPlanMenu(ctx: ExtensionContext, options: ReadyPlanMenuOptions) {
  type Screen = "ready" | "export";
  type Action = "implement-here" | "implement-fresh" | "export" | "save" | "stay" | "exit";
  const menu = defineMenu<undefined, Screen, Action, ExtensionContext>({
    start: "ready",
    screens: {
      ready: () => ({
        kind: "actions",
        title: "Proposed plan ready. What next?",
        lines: [...IMPLEMENTATION_CONTEXT_LINES, options.implementationOutcome()],
        items: [
          {
            id: "implement-here",
            label: "Implement here",
            description: "Continue in this session with the planning conversation.",
            action: "implement-here",
          },
          {
            id: "implement-fresh",
            label: "Start fresh and implement",
            description: "Open a new linked session; transfer only the approved plan.",
            action: "implement-fresh",
            busyLabel: "Starting fresh implementation session…",
          },
          { id: "export", label: "Export plan…", to: "export" },
          { id: "save", label: "Save for later", action: "save" },
          { id: "stay", label: "Stay in Plan mode", action: "stay" },
          { id: "exit", label: "Discard plan and exit", action: "exit" },
        ],
        hint: "close",
      }),
      export: () => planExportInputScreen(options.getExportDestination),
    },
    actions: {
      "implement-here": async () => {
        await options.implementHere();
        return { kind: "close" };
      },
      "implement-fresh": async ({ signal }) => {
        await options.implementFresh(signal);
        return { kind: "close" };
      },
      export: async ({ value, signal }) =>
        (await options.exportPlan(value ?? "", signal)) ? { kind: "close" } : { kind: "rejected" },
      save: async () => {
        options.save();
        return { kind: "close" };
      },
      stay: async () => {
        options.stay();
        return { kind: "close" };
      },
      exit: async () => {
        options.exit();
        return { kind: "close" };
      },
    },
  });
  await runMenu(withBorderedCustomUi(ctx), menu, {
    getState: () => undefined,
    signal: options.signal,
    isCurrent: options.isCurrent,
  });
}