import { afterEach, beforeAll, beforeEach, describe, expect, it, vi } from "bun:test";
import * as path from "node:path";
import { type } from "@oh-my-pi/omptype";
import { Agent, type AgentTool } from "@oh-my-pi/pi-agent-core";
import { type Api, Effort, type Model } from "@oh-my-pi/pi-ai";
import { resetSettingsForTest, Settings } from "@oh-my-pi/pi-coding-agent/config/settings";
import { initTheme } from "@oh-my-pi/pi-coding-agent/modes/theme/theme";
import { AgentSession } from "@oh-my-pi/pi-coding-agent/session/agent-session";
import { AuthStorage } from "@oh-my-pi/pi-coding-agent/session/auth-storage";
import { SessionManager } from "@oh-my-pi/pi-coding-agent/session/session-manager";
import { TempDir } from "@oh-my-pi/pi-utils";
import { ModelRegistry } from "../src/config/model-registry";
import type { CustomTool } from "../src/extensibility/custom-tools/types";
import { InteractiveMode } from "../src/modes/interactive-mode";
import { resolveXdevTool, type XdevState } from "../src/tools/xdev";

function makeTool(name: string): AgentTool {
	return {
		name,
		label: name,
		description: `Fake ${name}`,
		parameters: type({}),
		async execute() {
			return { content: [{ type: "text" as const, text: "ok" }] };
		},
	};
}

interface HarnessOptions {
	extraRegistryTools?: readonly AgentTool[];
	builtInToolNames?: Iterable<string>;
	rebuildGate?: { fail: boolean; calls?: number };
	xdev?: XdevState;
}

describe("InteractiveMode plan.defaultOnStartup", () => {
	let tempDir: TempDir;
	let authStorage: AuthStorage;
	let mode: InteractiveMode | undefined;
	let session: AgentSession | undefined;

	beforeAll(() => {
		initTheme();
	});

	beforeEach(async () => {
		resetSettingsForTest();
		tempDir = TempDir.createSync("@pi-default-plan-");
		await Settings.init({ inMemory: true, cwd: tempDir.path() });
		Settings.instance.set("startup.quiet", true);
		authStorage = await AuthStorage.create(path.join(tempDir.path(), "testauth.db"));
		authStorage.setRuntimeApiKey("anthropic", "test-key");
	});

	afterEach(async () => {
		vi.restoreAllMocks();
		mode?.stop();
		await session?.dispose();
		authStorage?.close();
		tempDir?.removeSync();
		mode = undefined;
		session = undefined;
		authStorage = undefined as unknown as AuthStorage;
		tempDir = undefined as unknown as TempDir;
		resetSettingsForTest();
	});

	function modelOrThrow(registry: ModelRegistry, id: string): Model<Api> {
		const model = registry.find("anthropic", id);
		if (!model) throw new Error(`Expected anthropic model ${id} to exist`);
		return model;
	}

	/** Build an InteractiveMode over a brand-new (never-persisted) session.
	 *  `extraRegistryTools` registers additional tools that are NOT initially
	 *  active — modeling tools hidden by `tools.discoveryMode === "all"` that
	 *  modes may force-activate on entry. `builtInToolNames` marks which registry
	 *  entries still have built-in provenance after extension shadowing. */
	function createHarness(settings: Settings, options: HarnessOptions = {}): InteractiveMode {
		const registry = new ModelRegistry(authStorage, path.join(tempDir.path(), `models-${Bun.nanoseconds()}.yml`));
		const initialModel = modelOrThrow(registry, "claude-sonnet-4-5");
		const readTool = makeTool("read");
		// AgentSession requires a Map-typed tool registry; `read` is the initial
		// active tool. Plan approval is a `write` to xd://propose, so plan-mode
		// entry only augments the built-in `write` tool when present.
		const xdev = options.xdev;
		const toolRegistry = xdev?.tools ?? new Map<string, AgentTool>();
		toolRegistry.set(readTool.name, readTool);
		for (const tool of options.extraRegistryTools ?? []) {
			toolRegistry.set(tool.name, tool);
		}
		const manager = SessionManager.create(tempDir.path(), path.join(tempDir.path(), `active-${Bun.nanoseconds()}`));
		const createdSession = new AgentSession({
			agent: new Agent({
				initialState: {
					model: initialModel,
					systemPrompt: ["Test"],
					tools: [readTool],
					messages: [],
					thinkingLevel: Effort.Medium,
				},
			}),
			sessionManager: manager,
			settings,
			modelRegistry: registry,
			toolRegistry,
			builtInToolNames: options.builtInToolNames ?? ["read"],
			rebuildSystemPrompt: options.rebuildGate
				? async () => {
						if (options.rebuildGate) options.rebuildGate.calls = (options.rebuildGate.calls ?? 0) + 1;
						if (options.rebuildGate?.fail) throw new Error("rebuild failed");
						return { systemPrompt: ["Test"] };
					}
				: undefined,
			xdev,
		});
		session = createdSession;
		mode = new InteractiveMode(createdSession, "test");
		return mode;
	}

	it("enters plan mode at startup when the setting is enabled", async () => {
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }));

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(true);
		expect(session?.getPlanModeState()).toMatchObject({ enabled: true, planFilePath: "local://PLAN.md" });
		expect(session?.getActiveToolNames()).toContain("read");
	});

	it("activates write when entering plan mode even if it was hidden by discoveryMode (issue #3165)", async () => {
		// `plan-mode-active.md` instructs the agent to draft the plan file with
		// `write` and refine it with `edit`. Under `tools.discoveryMode === "all"`
		// `write` is hidden behind `search_tool_bm25` so it's in the registry but
		// not the initial active set. Plan-mode entry must force-activate it or
		// the agent only has `edit`, which fails on a non-existent file.
		const writeTool = makeTool("write");
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }), {
			extraRegistryTools: [writeTool],
			builtInToolNames: ["read", "write"],
		});

		expect(session?.getActiveToolNames()).not.toContain("write");

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(true);
		expect(session?.getActiveToolNames()).toContain("write");
	});

	it("does not activate an extension-shadowed write tool in plan mode", async () => {
		const shadowWriteTool = makeTool("write");
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }), {
			extraRegistryTools: [shadowWriteTool],
		});

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(true);
		expect(session?.getActiveToolNames()).not.toContain("write");
	});

	it("removes plan-only write when exiting to the previous read-only tool set", async () => {
		const writeTool = makeTool("write");
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }), {
			extraRegistryTools: [writeTool],
			builtInToolNames: ["read", "write"],
		});
		await created.init({ suppressWelcomeIntro: true });
		expect(session?.getActiveToolNames()).toContain("write");

		await created.handlePlanModeCommand();

		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
		expect(session?.getActiveToolNames()).toEqual(["read"]);
	});

	it("keeps plan mode retryable when prior-tool restoration fails", async () => {
		const writeTool = makeTool("write");
		const rebuildGate = { fail: false };
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }), {
			extraRegistryTools: [writeTool],
			builtInToolNames: ["read", "write"],
			rebuildGate,
		});
		await created.init({ suppressWelcomeIntro: true });
		const activeBefore = session?.getActiveToolNames();
		rebuildGate.fail = true;

		await expect(created.handlePlanModeCommand()).rejects.toThrow("rebuild failed");
		expect(created.planModeEnabled).toBe(true);
		expect(session?.getPlanModeState()?.enabled).toBe(true);
		expect(session?.getActiveToolNames()).toEqual(activeBefore);

		rebuildGate.fail = false;
		await created.handlePlanModeCommand();
		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
		expect(session?.getActiveToolNames()).toEqual(["read"]);
	});

	it("restores plan tool presentation when prior-model restoration fails", async () => {
		const settings = Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false });
		settings.setModelRole("plan", "anthropic/claude-haiku-4-5:high");
		const writeTool = makeTool("write");
		const planSelectedTool = makeTool("plan_selected");
		const mountedTool: CustomTool = {
			name: "mcp__ambient_search",
			label: "ambient/search",
			description: "Search ambient data",
			parameters: type({}),
			loadMode: "discoverable",
			mcpServerName: "ambient",
			mcpToolName: "search",
			async execute() {
				return { content: [{ type: "text", text: "ok" }] };
			},
		};
		const xdev: XdevState = {
			tools: new Map(),
			mountedNames: new Set(),
			builtInNames: new Set(["read", "write"]),
			isActive: name => session?.getActiveToolNames().includes(name) === true,
		};
		const created = createHarness(settings, {
			extraRegistryTools: [writeTool, planSelectedTool],
			builtInToolNames: ["read", "write"],
			xdev,
		});
		const previousModel = session?.model;
		await created.init({ suppressWelcomeIntro: true });
		const planModel = session?.model;
		await session!.refreshMCPTools([mountedTool]);
		await session!.setActiveToolsByName([...session!.getEnabledToolNames(), planSelectedTool.name]);
		const planTools = session!.getEnabledToolNames();
		const planActiveTools = session!.getActiveToolNames();
		const planMountedTools = session!.getMountedXdevToolNames();
		expect(planModel?.id).toBe("claude-haiku-4-5");
		expect(session?.configuredThinkingLevel()).toBe(Effort.High);
		expect(planActiveTools).toEqual(["read", "write", planSelectedTool.name]);
		expect(planMountedTools).toEqual([mountedTool.name]);
		expect(xdev.mountedNames.has(mountedTool.name)).toBe(true);

		const setModelTemporary = session!.setModelTemporary.bind(session);
		const restoreModel = vi.spyOn(session!, "setModelTemporary").mockImplementationOnce(async (...args) => {
			await setModelTemporary(...args);
			throw new Error("model restore failed after switch");
		});
		await expect(created.handlePlanModeCommand()).rejects.toThrow("model restore failed after switch");

		expect(created.planModeEnabled).toBe(true);
		expect(created.planModePaused).toBe(false);
		expect(session?.getPlanModeState()?.enabled).toBe(true);
		expect(session?.peekPlanProposalHandler()).toBeDefined();
		expect(session?.model?.id).toBe(planModel?.id);
		expect(session?.configuredThinkingLevel()).toBe(Effort.High);
		expect(session?.getEnabledToolNames()).toEqual(planTools);
		expect(session?.getActiveToolNames()).toEqual(planActiveTools);
		expect(session?.getMountedXdevToolNames()).toEqual(planMountedTools);
		expect(xdev.mountedNames.has(mountedTool.name)).toBe(true);

		restoreModel.mockRestore();
		await created.handlePlanModeCommand();
		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
		expect(session?.model?.id).toBe(previousModel?.id);
		// Pre-existing successful-exit behavior (unchanged by this fix): restoring the
		// pre-plan tool set drops the MCP device and plan-only selections entirely.
		expect(session?.getActiveToolNames()).toEqual(["read"]);
		expect(session?.getMountedXdevToolNames()).toEqual([]);
		expect(xdev.tools.has(mountedTool.name)).toBe(true);
		expect(resolveXdevTool(xdev, mountedTool.name)).toBeUndefined();
	});

	it("clears old plan UI state when target-session reconciliation restore fails", async () => {
		const writeTool = makeTool("write");
		const rebuildGate = { fail: false, calls: 0 };
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }), {
			extraRegistryTools: [writeTool],
			builtInToolNames: ["read", "write"],
			rebuildGate,
		});
		await created.init({ suppressWelcomeIntro: true });
		expect(created.planModeEnabled).toBe(true);
		expect(session?.peekPlanProposalHandler()).toBeDefined();

		const targetManager = SessionManager.create(tempDir.path(), path.join(tempDir.path(), "target-sessions"));
		await targetManager.flush();
		const targetSessionFile = targetManager.getSessionFile();
		expect(targetSessionFile).toBeString();
		await targetManager.close();
		const callsBeforeSwitch = rebuildGate.calls;
		rebuildGate.fail = true;

		await expect(session!.switchSession(targetSessionFile!)).resolves.toBe(true);
		expect(session?.sessionFile).toBe(targetSessionFile);
		expect(created.planModeEnabled).toBe(false);
		expect(rebuildGate.calls).toBeGreaterThan(callsBeforeSwitch);
		expect(created.planModePaused).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
		expect(session?.peekPlanProposalHandler()).toBeUndefined();
	});

	it("does not enter plan mode at startup by default", async () => {
		const created = createHarness(Settings.isolated({ "compaction.enabled": false }));

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
	});

	it("does not enter plan mode when the session has restored conversation", async () => {
		// A genuinely resumed session has prior conversation messages. Gating on
		// message entries (not the CLI resume flag) means a `--continue` that
		// created a *fresh* session still gets the startup default (above), while
		// one with restored conversation is left in its reconciled mode.
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }));
		created.sessionManager.appendMessage({ role: "user", content: "prior turn", timestamp: Date.now() });

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
	});

	it("preserves the restored model when resuming an active plan session", async () => {
		const created = createHarness(
			Settings.isolated({
				"compaction.enabled": false,
				modelRoles: { plan: "anthropic/claude-sonnet-4-6" },
			}),
		);
		created.sessionManager.appendModelChange("anthropic/claude-sonnet-4-5");
		created.sessionManager.appendModeChange("plan", { planFilePath: "local://PLAN.md" });
		created.sessionManager.appendMessage({ role: "user", content: "prior plan turn", timestamp: Date.now() });

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(true);
		expect(session?.model?.id).toBe("claude-sonnet-4-5");
	});

	it("enters plan mode for a fresh session that carries only startup metadata", async () => {
		// createAgentSession appends model_change / thinking_level_change for a
		// brand-new session before init(); those are not conversation history, so
		// the startup default must still apply (regression: gating on entry count
		// instead of message entries skipped plan mode for every real new session).
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }));
		created.sessionManager.appendModelChange("anthropic/claude-sonnet-4-5");
		created.sessionManager.appendThinkingLevelChange("medium");

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(true);
		expect(session?.getPlanModeState()).toMatchObject({ enabled: true });
	});

	it("enters plan mode for a fresh session that carries an extension custom entry", async () => {
		// An extension can persist a custom entry during session_start; that is not
		// conversation or a mode change, so the startup default must still apply
		// (regression: an allowlist of SDK metadata types skipped plan mode here).
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }));
		created.sessionManager.appendModelChange("anthropic/claude-sonnet-4-5");
		created.sessionManager.appendCustomEntry("my-extension-state", { foo: "bar" });

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(true);
		expect(session?.getPlanModeState()).toMatchObject({ enabled: true });
	});

	it("does not enter plan mode for a compacted session with no trailing message", async () => {
		// A compacted branch carries summary context (buildSessionContext emits the
		// compaction summary as a message), so it is not fresh even without a literal
		// `message` entry; the startup default must not override its restored mode.
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }));
		created.sessionManager.appendModelChange("anthropic/claude-sonnet-4-5");
		created.sessionManager.appendCompaction("prior conversation summary", undefined, "first-kept", 1000);

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
	});

	it("does not re-enter plan mode when a restored mode_change turned it off (no message yet)", async () => {
		// User enabled plan, toggled it off (mode_change "none"), then quit before
		// sending a turn. On --continue the reconciler restores that off state; the
		// startup default must not override it just because there is no message entry.
		const created = createHarness(Settings.isolated({ "plan.defaultOnStartup": true, "compaction.enabled": false }));
		created.sessionManager.appendModeChange("plan", { planFilePath: "local://PLAN.md" });
		created.sessionManager.appendModeChange("none");

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
	});

	it("does not enter plan mode when plan mode is globally disabled", async () => {
		const created = createHarness(
			Settings.isolated({ "plan.defaultOnStartup": true, "plan.enabled": false, "compaction.enabled": false }),
		);

		await created.init({ suppressWelcomeIntro: true });

		expect(created.planModeEnabled).toBe(false);
		expect(session?.getPlanModeState()).toBeUndefined();
	});
});