import { createExecutionContext, runInDurableObject } from "cloudflare:test";
import { env } from "cloudflare:workers";
import { describe, it, vi } from "vitest";
import { InstanceEvent, InstanceStatus } from "../src";
import { WorkflowBinding } from "../src/binding";
import { setTestWorkflowCallback } from "./test-entry";
import type { WorkflowHandle } from "../src/binding";
import type { Engine, EngineLogs } from "../src/engine";
import type { WorkflowEvent } from "cloudflare:workers";

let instanceCounter = 0;
function uniqueId(prefix = "instance"): string {
	return `${prefix}-${++instanceCounter}`;
}

function createBinding(): WorkflowBinding {
	const ctx = createExecutionContext();
	return new WorkflowBinding(ctx, {
		ENGINE: env.ENGINE,
		BINDING_NAME: "TEST_WORKFLOW",
		WORKFLOW_NAME: "test-workflow",
	});
}

async function waitUntilLogEvent(
	engineStub: DurableObjectStub<Engine>,
	event: InstanceEvent,
	timeout = 5000
): Promise<void> {
	await vi.waitUntil(
		async () => {
			const logs = (await engineStub.readLogs()) as EngineLogs;
			const hasEvent = logs.logs.some((log) => log.event === event);
			return hasEvent;
		},
		{ timeout }
	);
}

describe("WorkflowBinding", () => {
	describe("create()", () => {
		it("should create an instance with provided id and params", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (event) => {
				return (event as WorkflowEvent<{ key: string }>).payload;
			});

			const params = { key: "test-value" };
			const result = await binding.create({ id, params });

			expect(result.id).toBe(id);

			await waitUntilLogEvent(engineStub, InstanceEvent.WORKFLOW_SUCCESS);

			const instance = await binding.get(id);
			const status = await instance.status();
			expect(status.output).toEqual(params);
		});

		it("should pass the workflow name in the event", async ({ expect }) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (event) => {
				return (event as WorkflowEvent<unknown>).workflowName;
			});

			await binding.create({ id });

			await waitUntilLogEvent(engineStub, InstanceEvent.WORKFLOW_SUCCESS);

			const instance = await binding.get(id);
			const status = await instance.status();
			expect(status.output).toBe("test-workflow");
		});

		it("should auto-generate id when not provided", async ({ expect }) => {
			const binding = createBinding();
			setTestWorkflowCallback(async () => "done");
			const result = await binding.create();

			expect(result.id).toBeDefined();
			expect(result.id.length).toBeGreaterThan(0);

			// Wait for the workflow to complete before the test ends so
			// the fire-and-forget init() RPC settles before teardown.
			const instance = await binding.get(result.id);
			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "complete";
				},
				{ timeout: 5000 }
			);
		});

		it("should throw WorkflowError for invalid instance id", async ({
			expect,
		}) => {
			const binding = createBinding();
			await expect(binding.create({ id: "#invalid!" })).rejects.toThrow(
				"Workflow instance has invalid id"
			);
		});
	});

	describe("get()", () => {
		it("should return a WorkflowHandle for an existing instance", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async () => "done");
			await binding.create({ id });

			const instance = await binding.get(id);

			expect(instance).toMatchObject({
				id,
				status: expect.any(Function),
				pause: expect.any(Function),
				resume: expect.any(Function),
				terminate: expect.any(Function),
				restart: expect.any(Function),
			});

			// Wait for the workflow to complete before the test ends so
			// the fire-and-forget init() RPC settles before teardown.
			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "complete";
				},
				{ timeout: 5000 }
			);
		});
	});

	describe("createBatch()", () => {
		it("should create multiple instances in a batch", async ({ expect }) => {
			const binding = createBinding();
			const ids = ["batch-1", "batch-2", "batch-3"];
			setTestWorkflowCallback(async () => "done");

			const results = await binding.createBatch(ids.map((id) => ({ id })));

			expect(results).toHaveLength(3);
			expect(results.map((r) => r.id)).toEqual(ids);

			for (const id of ids) {
				const instance = await binding.get(id);
				expect(instance.id).toBe(id);
			}

			// Wait for all batch workflows to complete before the test ends
			// so the fire-and-forget init() RPCs settle before teardown.
			for (const id of ids) {
				const instance = await binding.get(id);
				await vi.waitUntil(
					async () => {
						const s = await instance.status();
						return s.status === "complete";
					},
					{ timeout: 5000 }
				);
			}
		});

		it("should throw error for empty batch", async ({ expect }) => {
			const binding = createBinding();

			await expect(binding.createBatch([])).rejects.toThrow(
				"WorkflowError: batchCreate should have at least 1 instance"
			);
		});
	});
});

describe("WorkflowBinding", () => {
	it("should not call dispose when sending an event to an instance", async ({
		expect,
	}) => {
		const id = uniqueId();
		const binding = createBinding();
		const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

		setTestWorkflowCallback(async (_event, step) => {
			const receivedEvent = await step.waitForEvent("wait-for-test-event", {
				type: "test-event",
				timeout: "10 seconds",
			});
			return receivedEvent;
		});

		const createdInstance = await binding.create({ id });
		expect(createdInstance.id).toBe(id);

		const instance = await binding.get(id);
		expect(instance.id).toBe(id);

		const disposeSpy = vi.fn();

		await runInDurableObject<Engine, void>(engineStub, (engine) => {
			const originalReceiveEvent = engine.receiveEvent.bind(engine);
			engine.receiveEvent = (event) => {
				const result = originalReceiveEvent(event);
				return Object.assign(result, {
					[Symbol.dispose]: disposeSpy,
				});
			};
		});

		using _ = (await instance.sendEvent({
			type: "test-event",
			payload: { test: "data" },
		})) as unknown as Disposable;

		await vi.waitUntil(
			async () => {
				const status = await instance.status();
				return status.status === "complete";
			},
			{ timeout: 5000 }
		);

		expect(disposeSpy).not.toHaveBeenCalled();
	});
});

describe("WorkflowHandle", () => {
	describe("status()", () => {
		it("should return running status for a workflow waiting for an event", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.waitForEvent("wait-for-event", {
					type: "some-event",
					timeout: "2 seconds",
				});
				return "completed";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WAIT_START);

			const instance = await binding.get(id);
			const status = await instance.status();

			expect(status.status).toBe("running");
			expect(status.output).toBeNull();
			expect(status.error).toBeUndefined();

			// Terminate the waiting workflow so the init() RPC settles
			// before teardown (the 2-second waitForEvent timeout would
			// otherwise leave the workflow running past test end).
			await instance.terminate();
		});

		it("should return complete status and output for a successful workflow", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));
			const expectedOutput = { result: "success", value: 42 };

			setTestWorkflowCallback(async () => expectedOutput);
			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WORKFLOW_SUCCESS);

			const instance = await binding.get(id);
			const status = await instance.status();

			expect(status.status).toBe("complete");
			expect(status.output).toEqual(expectedOutput);
			expect(status.error).toBeUndefined();
		});

		it("should return errored status and error for a failed workflow", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async () => {
				throw new Error("Workflow failed intentionally");
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WORKFLOW_FAILURE);

			const instance = await binding.get(id);
			const status = await instance.status();

			expect(status.status).toBe("errored");
			expect(status.error).toBeDefined();
			expect(status.error?.message).toBe("Workflow failed intentionally");
			expect(status.output).toBeNull();
		});

		it("should return step outputs in __LOCAL_DEV_STEP_OUTPUTS", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				const step1Result = await step.do(
					"step-1",
					async () => "result-from-step-1"
				);
				const step2Result = await step.do("step-2", async () => ({
					data: "result-from-step-2",
				}));
				const step3Result = await step.do("step-3", async () => 123);
				return { step1Result, step2Result, step3Result };
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WORKFLOW_SUCCESS);

			const instance = (await binding.get(id)) as WorkflowHandle;
			const status = await instance.status();

			expect(status.status).toBe("complete");
			expect(status.__LOCAL_DEV_STEP_OUTPUTS).toHaveLength(3);
			expect(status.__LOCAL_DEV_STEP_OUTPUTS[0]).toBe("result-from-step-1");
			expect(status.__LOCAL_DEV_STEP_OUTPUTS[1]).toEqual({
				data: "result-from-step-2",
			});
			expect(status.__LOCAL_DEV_STEP_OUTPUTS[2]).toBe(123);
		});

		it("should return terminated status for a terminated instance", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.waitForEvent("wait-for-event", {
					type: "some-event",
					timeout: "1 second",
				});
				return "completed";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WAIT_START);

			const instance = await binding.get(id);
			await instance.terminate();

			const newInstance = await binding.get(id);
			const status = await newInstance.status();

			expect(status.status).toBe("terminated");
		});
	});

	describe("sendEvent()", () => {
		it("should deliver event payload to a waiting workflow", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				const receivedEvent = await step.waitForEvent("wait-for-event", {
					type: "my-event-type",
					timeout: "2 seconds",
				});
				return receivedEvent;
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WAIT_START);

			const instance = await binding.get(id);
			const eventPayload = { message: "hello", count: 42 };

			await instance.sendEvent({
				type: "my-event-type",
				payload: eventPayload,
			});

			await vi.waitUntil(
				async () => {
					const status = await instance.status();
					return status.status === "complete";
				},
				{ timeout: 5000 }
			);

			const status = await instance.status();
			expect(status.output).toMatchObject({
				payload: eventPayload,
				type: "my-event-type",
			});
		});

		it("should handle multiple sequential events", async ({ expect }) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				const event1 = await step.waitForEvent("wait-1", {
					type: "event-type-1",
					timeout: "10 seconds",
				});
				const event2 = await step.waitForEvent("wait-2", {
					type: "event-type-2",
					timeout: "10 seconds",
				});
				return { first: event1.payload, second: event2.payload };
			});

			await binding.create({ id });
			const instance = await binding.get(id);

			await waitUntilLogEvent(engineStub, InstanceEvent.WAIT_START);
			await instance.sendEvent({
				type: "event-type-1",
				payload: { value: "first" },
			});

			// Wait for the second waitForEvent
			await vi.waitUntil(
				async () => {
					const logs = (await engineStub.readLogs()) as EngineLogs;
					const waitStarts = logs.logs.filter(
						(log) => log.event === InstanceEvent.WAIT_START
					);
					return waitStarts.length === 2;
				},
				{ timeout: 5000 }
			);

			await instance.sendEvent({
				type: "event-type-2",
				payload: { value: "second" },
			});

			await vi.waitUntil(
				async () => {
					const status = await instance.status();
					return status.status === "complete";
				},
				{ timeout: 5000 }
			);

			const status = await instance.status();
			expect(status.output).toEqual({
				first: { value: "first" },
				second: { value: "second" },
			});
		});
	});

	describe("terminate()", () => {
		it("should terminate a running workflow instance", async ({ expect }) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.waitForEvent("wait-for-event", {
					type: "some-event",
					timeout: "1 second",
				});
				await step.do("should not be called", async () => {
					return "should not be called";
				});
				return "should never complete";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WAIT_START);

			const instance = await binding.get(id);
			await instance.terminate();

			// Get a new stub since the engine was aborted
			const newEngineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			const status = await runInDurableObject(newEngineStub, (engine) => {
				return engine.getStatus();
			});
			expect(status).toBe(InstanceStatus.Terminated);

			const logs = (await newEngineStub.readLogs()) as EngineLogs;
			const hasTerminatedEvent = logs.logs.some(
				(log) => log.event === InstanceEvent.WORKFLOW_TERMINATED
			);
			expect(hasTerminatedEvent).toBe(true);

			// assert that step.do never started
			const hasStepStart = logs.logs.some(
				(log) => log.event === InstanceEvent.STEP_START
			);
			expect(hasStepStart).toBe(false);
		});
	});

	describe("restart()", () => {
		it("should restart a workflow instance", async ({ expect }) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.sleep("sleep", 250);
				return "complete";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.WORKFLOW_SUCCESS);

			let instance = await binding.get(id);
			let status = await instance.status();
			expect(status.status).toBe("complete");

			// restart() aborts the old DO, gets a fresh stub, and calls attemptRestart()
			// The service binding (USER_WORKFLOW) survives the abort, so no re-setup needed
			await instance.restart();

			const statusAfterRestart = await instance.status();
			expect(statusAfterRestart.status).toBe("running");

			// Wait for the restarted workflow to complete via status polling
			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "complete";
				},
				{ timeout: 5000 }
			);

			// Verify second run completed
			instance = await binding.get(id);
			status = await instance.status();
			expect(status.status).toBe("complete");
		});
	});

	describe("pause()", () => {
		it("should pause a running workflow", async ({ expect }) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.do("long-step", async () => {
					await scheduler.wait(500);
					return "result-1";
				});
				// step-2 should never run because pause takes effect after long-step
				await step.do("step-2", async () => "result-2");
				return "done";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.STEP_START);

			const instance = await binding.get(id);

			// Pause while long-step is in flight
			await instance.pause();

			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "paused";
				},
				{ timeout: 5000 }
			);

			const finalStatus = await instance.status();
			expect(finalStatus.status).toBe("paused");
		});
	});

	describe("resume()", () => {
		it("should resume a paused workflow and complete it", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.do("long-step", async () => {
					await scheduler.wait(500);
					return "result-1";
				});
				await step.do("step-2", async () => "result-2");
				return "all-done";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.STEP_START);

			const instance = await binding.get(id);

			// Pause while long-step is in flight
			await instance.pause();

			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "paused";
				},
				{ timeout: 5000 }
			);

			await instance.resume();

			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "complete";
				},
				{ timeout: 5000 }
			);

			const finalStatus = await instance.status();
			expect(finalStatus.status).toBe("complete");
			expect(finalStatus.output).toBe("all-done");
		});

		it("should cancel a pending pause when resume is called before step finishes", async ({
			expect,
		}) => {
			const id = uniqueId();
			const binding = createBinding();
			const engineStub = env.ENGINE.get(env.ENGINE.idFromName(id));

			setTestWorkflowCallback(async (_event, step) => {
				await step.do("long-step", async () => {
					await scheduler.wait(1000);
					return "long-result";
				});
				await step.do("step-after", async () => "final-result");
				return "completed";
			});

			await binding.create({ id });
			await waitUntilLogEvent(engineStub, InstanceEvent.STEP_START);

			const instance = await binding.get(id);

			// Pause while long-step is in flight — sets WaitingForPause
			await instance.pause();

			const statusAfterPause = await instance.status();
			expect(statusAfterPause.status).toBe("waitingForPause");

			// resume before the step finishes — this should cancel the pending pause
			await instance.resume();

			// status should go back to Running
			const statusAfterResume = await instance.status();
			expect(statusAfterResume.status).toBe("running");

			await vi.waitUntil(
				async () => {
					const s = await instance.status();
					return s.status === "complete";
				},
				{ timeout: 5000 }
			);

			const finalStatus = await instance.status();
			expect(finalStatus.status).toBe("complete");
			expect(finalStatus.output).toBe("completed");
		});
	});
});