import { expect, tap } from '@git.zone/tstest/tapbundle';
import * as taskbuffer from '../ts/index.js';
import * as smartdelay from '@push.rocks/smartdelay';

// Test 1: Task data property — typed data accessible
tap.test('should have typed data property on task', async () => {
  const task = new taskbuffer.Task<undefined, [], { domain: string; priority: number }>({
    name: 'data-task',
    data: { domain: 'example.com', priority: 1 },
    taskFunction: async () => {},
  });

  expect(task.data.domain).toEqual('example.com');
  expect(task.data.priority).toEqual(1);
});

// Test 2: Task data defaults to empty object
tap.test('should default data to empty object when not provided', async () => {
  const task = new taskbuffer.Task({
    name: 'no-data-task',
    taskFunction: async () => {},
  });

  expect(task.data).toBeTruthy();
  expect(typeof task.data).toEqual('object');
});

// Test 3: No-constraint passthrough — behavior unchanged
tap.test('should run tasks directly when no constraints are configured', async () => {
  const manager = new taskbuffer.TaskManager();
  let executed = false;

  const task = new taskbuffer.Task({
    name: 'passthrough-task',
    taskFunction: async () => {
      executed = true;
      return 'done';
    },
  });

  manager.addTask(task);
  const result = await manager.triggerTaskByName('passthrough-task');
  expect(executed).toBeTrue();
  expect(result).toEqual('done');
  await manager.stop();
});

// Test 4: Group concurrency — 3 tasks, max 2 concurrent, 3rd queues
tap.test('should enforce group concurrency limit', async () => {
  const manager = new taskbuffer.TaskManager();
  let running = 0;
  let maxRunning = 0;

  const constraint = new taskbuffer.TaskConstraintGroup<{ group: string }>({
    name: 'concurrency-test',
    maxConcurrent: 2,
    constraintKeyForTask: (task) =>
      task.data.group === 'workers' ? 'workers' : null,
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (id: number) =>
    new taskbuffer.Task<undefined, [], { group: string }>({
      name: `worker-${id}`,
      data: { group: 'workers' },
      taskFunction: async () => {
        running++;
        maxRunning = Math.max(maxRunning, running);
        await smartdelay.delayFor(200);
        running--;
      },
    });

  const t1 = makeTask(1);
  const t2 = makeTask(2);
  const t3 = makeTask(3);

  manager.addTask(t1);
  manager.addTask(t2);
  manager.addTask(t3);

  await Promise.all([
    manager.triggerTaskConstrained(t1),
    manager.triggerTaskConstrained(t2),
    manager.triggerTaskConstrained(t3),
  ]);

  expect(maxRunning).toBeLessThanOrEqual(2);
  await manager.stop();
});

// Test 5: Key-based mutual exclusion — same key sequential, different keys parallel
tap.test('should enforce key-based mutual exclusion', async () => {
  const manager = new taskbuffer.TaskManager();
  const log: string[] = [];

  const constraint = new taskbuffer.TaskConstraintGroup<{ domain: string }>({
    name: 'domain-mutex',
    maxConcurrent: 1,
    constraintKeyForTask: (task) => task.data.domain,
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (name: string, domain: string, delayMs: number) =>
    new taskbuffer.Task<undefined, [], { domain: string }>({
      name,
      data: { domain },
      taskFunction: async () => {
        log.push(`${name}-start`);
        await smartdelay.delayFor(delayMs);
        log.push(`${name}-end`);
      },
    });

  const taskA1 = makeTask('a1', 'a.com', 100);
  const taskA2 = makeTask('a2', 'a.com', 100);
  const taskB1 = makeTask('b1', 'b.com', 100);

  manager.addTask(taskA1);
  manager.addTask(taskA2);
  manager.addTask(taskB1);

  await Promise.all([
    manager.triggerTaskConstrained(taskA1),
    manager.triggerTaskConstrained(taskA2),
    manager.triggerTaskConstrained(taskB1),
  ]);

  // a1 and a2 should be sequential (same key)
  const a1EndIdx = log.indexOf('a1-end');
  const a2StartIdx = log.indexOf('a2-start');
  expect(a2StartIdx).toBeGreaterThanOrEqual(a1EndIdx);

  // b1 should start concurrently with a1 (different key)
  const a1StartIdx = log.indexOf('a1-start');
  const b1StartIdx = log.indexOf('b1-start');
  // Both should start before a1 ends
  expect(b1StartIdx).toBeLessThan(a1EndIdx);

  await manager.stop();
});

// Test 6: Cooldown enforcement
tap.test('should enforce cooldown between task executions', async () => {
  const manager = new taskbuffer.TaskManager();
  const timestamps: number[] = [];

  const constraint = new taskbuffer.TaskConstraintGroup<{ key: string }>({
    name: 'cooldown-test',
    maxConcurrent: 1,
    cooldownMs: 300,
    constraintKeyForTask: (task) => task.data.key,
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (name: string) =>
    new taskbuffer.Task<undefined, [], { key: string }>({
      name,
      data: { key: 'shared' },
      taskFunction: async () => {
        timestamps.push(Date.now());
      },
    });

  const t1 = makeTask('cool-1');
  const t2 = makeTask('cool-2');
  const t3 = makeTask('cool-3');

  manager.addTask(t1);
  manager.addTask(t2);
  manager.addTask(t3);

  await Promise.all([
    manager.triggerTaskConstrained(t1),
    manager.triggerTaskConstrained(t2),
    manager.triggerTaskConstrained(t3),
  ]);

  // Each execution should be at least ~300ms apart (with 200ms tolerance)
  for (let i = 1; i < timestamps.length; i++) {
    const gap = timestamps[i] - timestamps[i - 1];
    expect(gap).toBeGreaterThanOrEqual(250); // 300ms cooldown minus 50ms tolerance
  }

  await manager.stop();
});

// Test 7: Multiple constraint groups on one task
tap.test('should apply multiple constraint groups to one task', async () => {
  const manager = new taskbuffer.TaskManager();
  let running = 0;
  let maxRunning = 0;

  const globalConstraint = new taskbuffer.TaskConstraintGroup({
    name: 'global',
    maxConcurrent: 3,
    constraintKeyForTask: () => 'all',
  });

  const groupConstraint = new taskbuffer.TaskConstraintGroup<{ group: string }>({
    name: 'group',
    maxConcurrent: 1,
    constraintKeyForTask: (task) => task.data.group,
  });

  manager.addConstraintGroup(globalConstraint);
  manager.addConstraintGroup(groupConstraint);

  const makeTask = (name: string, group: string) =>
    new taskbuffer.Task<undefined, [], { group: string }>({
      name,
      data: { group },
      taskFunction: async () => {
        running++;
        maxRunning = Math.max(maxRunning, running);
        await smartdelay.delayFor(100);
        running--;
      },
    });

  // Same group - should be serialized by group constraint
  const t1 = makeTask('multi-1', 'A');
  const t2 = makeTask('multi-2', 'A');

  manager.addTask(t1);
  manager.addTask(t2);

  await Promise.all([
    manager.triggerTaskConstrained(t1),
    manager.triggerTaskConstrained(t2),
  ]);

  // With group maxConcurrent: 1, only 1 should run at a time
  expect(maxRunning).toBeLessThanOrEqual(1);
  await manager.stop();
});

// Test 8: Matcher returns null — task runs unconstrained
tap.test('should run task unconstrained when matcher returns null', async () => {
  const manager = new taskbuffer.TaskManager();

  const constraint = new taskbuffer.TaskConstraintGroup<{ skip: boolean }>({
    name: 'selective',
    maxConcurrent: 1,
    constraintKeyForTask: (task) => (task.data.skip ? null : 'constrained'),
  });
  manager.addConstraintGroup(constraint);

  let unconstrained = false;
  const task = new taskbuffer.Task<undefined, [], { skip: boolean }>({
    name: 'skip-task',
    data: { skip: true },
    taskFunction: async () => {
      unconstrained = true;
    },
  });

  manager.addTask(task);
  await manager.triggerTaskConstrained(task);
  expect(unconstrained).toBeTrue();
  await manager.stop();
});

// Test 9: Error handling — failed task releases slot, queue drains
tap.test('should release slot and drain queue when task fails', async () => {
  const manager = new taskbuffer.TaskManager();
  const log: string[] = [];

  const constraint = new taskbuffer.TaskConstraintGroup<{ key: string }>({
    name: 'error-drain',
    maxConcurrent: 1,
    constraintKeyForTask: (task) => task.data.key,
  });
  manager.addConstraintGroup(constraint);

  const failTask = new taskbuffer.Task<undefined, [], { key: string }>({
    name: 'fail-task',
    data: { key: 'shared' },
    catchErrors: true,
    taskFunction: async () => {
      log.push('fail');
      throw new Error('intentional');
    },
  });

  const successTask = new taskbuffer.Task<undefined, [], { key: string }>({
    name: 'success-task',
    data: { key: 'shared' },
    taskFunction: async () => {
      log.push('success');
    },
  });

  manager.addTask(failTask);
  manager.addTask(successTask);

  await Promise.all([
    manager.triggerTaskConstrained(failTask),
    manager.triggerTaskConstrained(successTask),
  ]);

  expect(log).toContain('fail');
  expect(log).toContain('success');
  await manager.stop();
});

// Test 10: TaskManager integration — addConstraintGroup + triggerTaskByName
tap.test('should route triggerTaskByName through constraints', async () => {
  const manager = new taskbuffer.TaskManager();
  let running = 0;
  let maxRunning = 0;

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'manager-integration',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'all',
  });
  manager.addConstraintGroup(constraint);

  const t1 = new taskbuffer.Task({
    name: 'managed-1',
    taskFunction: async () => {
      running++;
      maxRunning = Math.max(maxRunning, running);
      await smartdelay.delayFor(100);
      running--;
    },
  });

  const t2 = new taskbuffer.Task({
    name: 'managed-2',
    taskFunction: async () => {
      running++;
      maxRunning = Math.max(maxRunning, running);
      await smartdelay.delayFor(100);
      running--;
    },
  });

  manager.addTask(t1);
  manager.addTask(t2);

  await Promise.all([
    manager.triggerTaskByName('managed-1'),
    manager.triggerTaskByName('managed-2'),
  ]);

  expect(maxRunning).toBeLessThanOrEqual(1);
  await manager.stop();
});

// Test 11: removeConstraintGroup removes by name
tap.test('should remove a constraint group by name', async () => {
  const manager = new taskbuffer.TaskManager();

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'removable',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'all',
  });

  manager.addConstraintGroup(constraint);
  expect(manager.constraintGroups.length).toEqual(1);

  manager.removeConstraintGroup('removable');
  expect(manager.constraintGroups.length).toEqual(0);
  await manager.stop();
});

// Test 12: TaskConstraintGroup reset clears state
tap.test('should reset constraint group state', async () => {
  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'resettable',
    maxConcurrent: 2,
    cooldownMs: 1000,
    constraintKeyForTask: () => 'key',
  });

  // Simulate usage
  constraint.acquireSlot('key');
  expect(constraint.getRunningCount('key')).toEqual(1);

  constraint.releaseSlot('key');
  expect(constraint.getCooldownRemaining('key')).toBeGreaterThan(0);

  constraint.reset();
  expect(constraint.getRunningCount('key')).toEqual(0);
  expect(constraint.getCooldownRemaining('key')).toEqual(0);
});

// Test 13: Queued task returns correct result
tap.test('should return correct result from queued tasks', async () => {
  const manager = new taskbuffer.TaskManager();

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'return-value-test',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'shared',
  });
  manager.addConstraintGroup(constraint);

  const t1 = new taskbuffer.Task({
    name: 'ret-1',
    taskFunction: async () => {
      await smartdelay.delayFor(100);
      return 'result-A';
    },
  });

  const t2 = new taskbuffer.Task({
    name: 'ret-2',
    taskFunction: async () => {
      return 'result-B';
    },
  });

  manager.addTask(t1);
  manager.addTask(t2);

  const [r1, r2] = await Promise.all([
    manager.triggerTaskConstrained(t1),
    manager.triggerTaskConstrained(t2),
  ]);

  expect(r1).toEqual('result-A');
  expect(r2).toEqual('result-B');
  await manager.stop();
});

// Test 14: Error propagation for queued tasks (catchErrors: false)
tap.test('should propagate errors from queued tasks (catchErrors: false)', async () => {
  const manager = new taskbuffer.TaskManager();

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'error-propagation',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'shared',
  });
  manager.addConstraintGroup(constraint);

  const t1 = new taskbuffer.Task({
    name: 'err-first',
    taskFunction: async () => {
      await smartdelay.delayFor(100);
      return 'ok';
    },
  });

  const t2 = new taskbuffer.Task({
    name: 'err-second',
    catchErrors: false,
    taskFunction: async () => {
      throw new Error('queued-error');
    },
  });

  manager.addTask(t1);
  manager.addTask(t2);

  const r1Promise = manager.triggerTaskConstrained(t1);
  const r2Promise = manager.triggerTaskConstrained(t2);

  const r1 = await r1Promise;
  expect(r1).toEqual('ok');

  let caughtError: Error | null = null;
  try {
    await r2Promise;
  } catch (err) {
    caughtError = err as Error;
  }

  expect(caughtError).toBeTruthy();
  expect(caughtError!.message).toEqual('queued-error');
  await manager.stop();
});

// Test 15: triggerTask() routes through constraints
tap.test('should route triggerTask() through constraints', async () => {
  const manager = new taskbuffer.TaskManager();
  let running = 0;
  let maxRunning = 0;

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'trigger-task-test',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'all',
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (id: number) =>
    new taskbuffer.Task({
      name: `tt-${id}`,
      taskFunction: async () => {
        running++;
        maxRunning = Math.max(maxRunning, running);
        await smartdelay.delayFor(100);
        running--;
      },
    });

  const t1 = makeTask(1);
  const t2 = makeTask(2);

  manager.addTask(t1);
  manager.addTask(t2);

  await Promise.all([
    manager.triggerTask(t1),
    manager.triggerTask(t2),
  ]);

  expect(maxRunning).toBeLessThanOrEqual(1);
  await manager.stop();
});

// Test 16: addExecuteRemoveTask() routes through constraints
tap.test('should route addExecuteRemoveTask() through constraints', async () => {
  const manager = new taskbuffer.TaskManager();
  let running = 0;
  let maxRunning = 0;

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'add-execute-remove-test',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'all',
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (id: number) =>
    new taskbuffer.Task({
      name: `aer-${id}`,
      taskFunction: async () => {
        running++;
        maxRunning = Math.max(maxRunning, running);
        await smartdelay.delayFor(100);
        running--;
        return `done-${id}`;
      },
    });

  const t1 = makeTask(1);
  const t2 = makeTask(2);

  const [report1, report2] = await Promise.all([
    manager.addExecuteRemoveTask(t1),
    manager.addExecuteRemoveTask(t2),
  ]);

  expect(maxRunning).toBeLessThanOrEqual(1);
  expect(report1.result).toEqual('done-1');
  expect(report2.result).toEqual('done-2');
  await manager.stop();
});

// Test 17: FIFO ordering of queued tasks
tap.test('should execute queued tasks in FIFO order', async () => {
  const manager = new taskbuffer.TaskManager();
  const executionOrder: string[] = [];

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'fifo-test',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'shared',
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (id: string) =>
    new taskbuffer.Task({
      name: `fifo-${id}`,
      taskFunction: async () => {
        executionOrder.push(id);
        await smartdelay.delayFor(50);
      },
    });

  const tA = makeTask('A');
  const tB = makeTask('B');
  const tC = makeTask('C');

  manager.addTask(tA);
  manager.addTask(tB);
  manager.addTask(tC);

  await Promise.all([
    manager.triggerTaskConstrained(tA),
    manager.triggerTaskConstrained(tB),
    manager.triggerTaskConstrained(tC),
  ]);

  expect(executionOrder).toEqual(['A', 'B', 'C']);
  await manager.stop();
});

// Test 18: Combined concurrency + cooldown
tap.test('should enforce both concurrency and cooldown together', async () => {
  const manager = new taskbuffer.TaskManager();
  let running = 0;
  let maxRunning = 0;
  const timestamps: number[] = [];

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'combined-test',
    maxConcurrent: 2,
    cooldownMs: 200,
    constraintKeyForTask: () => 'shared',
  });
  manager.addConstraintGroup(constraint);

  const makeTask = (id: number) =>
    new taskbuffer.Task({
      name: `combo-${id}`,
      taskFunction: async () => {
        running++;
        maxRunning = Math.max(maxRunning, running);
        timestamps.push(Date.now());
        await smartdelay.delayFor(100);
        running--;
      },
    });

  const tasks = [makeTask(1), makeTask(2), makeTask(3), makeTask(4)];
  for (const t of tasks) {
    manager.addTask(t);
  }

  await Promise.all(tasks.map((t) => manager.triggerTaskConstrained(t)));

  // Concurrency never exceeded 2
  expect(maxRunning).toBeLessThanOrEqual(2);

  // First 2 tasks start nearly together, 3rd task starts after first batch completes + cooldown
  // First batch completes ~100ms after start, then 200ms cooldown
  const gap = timestamps[2] - timestamps[0];
  expect(gap).toBeGreaterThanOrEqual(250); // 100ms task + 200ms cooldown - 50ms tolerance

  await manager.stop();
});

// Test 19: Constraint removal unblocks queued tasks
tap.test('should unblock queued tasks when constraint group is removed', async () => {
  const manager = new taskbuffer.TaskManager();
  const log: string[] = [];

  const constraint = new taskbuffer.TaskConstraintGroup({
    name: 'removable-constraint',
    maxConcurrent: 1,
    constraintKeyForTask: () => 'shared',
  });
  manager.addConstraintGroup(constraint);

  const t1 = new taskbuffer.Task({
    name: 'block-1',
    taskFunction: async () => {
      log.push('t1-start');
      // Remove constraint while t1 is running so t2 runs unconstrained after drain
      manager.removeConstraintGroup('removable-constraint');
      await smartdelay.delayFor(100);
      log.push('t1-end');
    },
  });

  const t2 = new taskbuffer.Task({
    name: 'block-2',
    taskFunction: async () => {
      log.push('t2-start');
      log.push('t2-end');
    },
  });

  manager.addTask(t1);
  manager.addTask(t2);

  await Promise.all([
    manager.triggerTaskConstrained(t1),
    manager.triggerTaskConstrained(t2),
  ]);

  // Both tasks completed (drain didn't deadlock after constraint removal)
  expect(log).toContain('t1-start');
  expect(log).toContain('t1-end');
  expect(log).toContain('t2-start');
  expect(log).toContain('t2-end');

  // t2 started after t1 completed (drain fires after t1 finishes)
  const t1EndIdx = log.indexOf('t1-end');
  const t2StartIdx = log.indexOf('t2-start');
  expect(t2StartIdx).toBeGreaterThanOrEqual(t1EndIdx);

  await manager.stop();
});

export default tap.start();