import { describe, test, expect, beforeEach, mock } from 'bun:test'
import { mockConfigModule } from './helpers/mock-config'

// Mock config before imports
mock.module('../config', () => mockConfigModule({ pollTimeout: 1 })) // Short timeout for tests

import {
  storeReset,
  storeCreateEnvironment,
  storeCreateSession,
  storeGetWorkItem,
  storeGetPendingWorkItem,
} from '../store'
import {
  createWorkItem,
  pollWork,
  ackWork,
  stopWork,
  heartbeatWork,
  reconnectWorkForEnvironment,
} from '../services/work-dispatch'

describe('Work Dispatch', () => {
  let envId: string
  let sessionId: string

  beforeEach(() => {
    storeReset()
    const env = storeCreateEnvironment({ secret: 's' })
    envId = env.id
    const session = storeCreateSession({ environmentId: envId })
    sessionId = session.id
  })

  describe('createWorkItem', () => {
    test('creates work item for active environment', async () => {
      const workId = await createWorkItem(envId, sessionId)
      expect(workId).toMatch(/^work_/)
      const item = storeGetWorkItem(workId)
      expect(item?.state).toBe('pending')
      expect(item?.sessionId).toBe(sessionId)
    })

    test('throws for non-existent environment', async () => {
      await expect(createWorkItem('env_no', sessionId)).rejects.toThrow(
        'not found',
      )
    })

    test('throws for inactive environment', async () => {
      const inactiveEnv = storeCreateEnvironment({ secret: 's2' })
      // Manually set status to deregistered
      const { storeUpdateEnvironment } = await import('../store')
      storeUpdateEnvironment(inactiveEnv.id, { status: 'deregistered' })
      await expect(createWorkItem(inactiveEnv.id, sessionId)).rejects.toThrow(
        'not active',
      )
    })

    test('encodes work secret as base64 JSON', async () => {
      const workId = await createWorkItem(envId, sessionId)
      const item = storeGetWorkItem(workId)
      const decoded = JSON.parse(
        Buffer.from(item!.secret, 'base64url').toString(),
      )
      expect(decoded.version).toBe(1)
      expect(decoded.session_ingress_token).toBe('test-api-key')
      expect(decoded.api_base_url).toBe('http://localhost:3000')
    })
  })

  describe('pollWork', () => {
    test('returns null when no work available (timeout)', async () => {
      const result = await pollWork(envId, 0.1)
      expect(result).toBeNull()
    })

    test('marks work as dispatched on poll (prevents immediate re-poll)', async () => {
      const workId = await createWorkItem(envId, sessionId)
      const result = await pollWork(envId, 1)
      expect(result).not.toBeNull()
      expect(result!.id).toBe(workId)
      // Atomically transitions to dispatched so the next poll doesn't re-return
      // the same item (prevents tight-loop re-polling when ackWork is slow/fails).
      expect(result!.state).toBe('dispatched')
      expect(result!.data.type).toBe('session')
      expect(result!.data.id).toBe(sessionId)
      // Dispatched items are not pending — next poll won't return them
      expect(storeGetPendingWorkItem(envId)).toBeUndefined()
      // After ack, it is no longer pending
      ackWork(workId)
      expect(storeGetPendingWorkItem(envId)).toBeUndefined()
    })

    test('does not return work for different environment', async () => {
      const env2 = storeCreateEnvironment({ secret: 's2' })
      await createWorkItem(envId, sessionId)
      const result = await pollWork(env2.id, 0.1)
      expect(result).toBeNull()
    })
  })

  describe('ackWork', () => {
    test('marks work as acked', async () => {
      const workId = await createWorkItem(envId, sessionId)
      ackWork(workId)
      expect(storeGetWorkItem(workId)?.state).toBe('acked')
    })
  })

  describe('stopWork', () => {
    test('marks work as completed', async () => {
      const workId = await createWorkItem(envId, sessionId)
      stopWork(workId)
      expect(storeGetWorkItem(workId)?.state).toBe('completed')
    })
  })

  describe('heartbeatWork', () => {
    test('extends lease and returns heartbeat info', async () => {
      const workId = await createWorkItem(envId, sessionId)
      const result = heartbeatWork(workId)
      expect(result.lease_extended).toBe(true)
      expect(result.ttl_seconds).toBe(40) // heartbeatInterval * 2
      expect(result.last_heartbeat).toBeTruthy()
    })

    test('returns default state for non-existent work', async () => {
      const result = heartbeatWork('work_no')
      expect(result.state).toBe('acked')
    })
  })

  describe('reconnectWorkForEnvironment', () => {
    test('creates work items for idle sessions in environment', async () => {
      // Create another idle session
      storeCreateSession({ environmentId: envId })
      const workIds = await reconnectWorkForEnvironment(envId)
      expect(workIds).toHaveLength(2)
      for (const id of workIds) {
        expect(storeGetWorkItem(id)?.state).toBe('pending')
      }
    })

    test('skips non-idle sessions', async () => {
      const activeSession = storeCreateSession({ environmentId: envId })
      const { storeUpdateSession } = await import('../store')
      storeUpdateSession(activeSession.id, { status: 'active' })
      const workIds = await reconnectWorkForEnvironment(envId)
      // Only the original idle session should get work
      expect(workIds).toHaveLength(1)
    })

    test('returns empty for environment with no sessions', async () => {
      const emptyEnv = storeCreateEnvironment({ secret: 's_empty' })
      const workIds = await reconnectWorkForEnvironment(emptyEnv.id)
      expect(workIds).toHaveLength(0)
    })
  })
})