import { http, HttpResponse, delay } from 'msw'
import type { JobStatus } from '../types'

const API_BASE = import.meta.env.VITE_API_URL || 'http://localhost:7860'

// In-memory job store for mocking
interface MockJob {
  id: string
  caseId: string
  status: JobStatus
  progress: number
  progressMessage: string
  elapsedSeconds: number
  fastMode: boolean
  createdAt: number
}

const mockJobs = new Map<string, MockJob>()
let jobCounter = 0

// Configurable job duration for tests (ms)
// Default: 500ms for fast tests
let mockJobDurationMs = 500

/**
 * Set the mock job duration for tests.
 * Jobs will complete after this many milliseconds.
 */
export function setMockJobDuration(durationMs: number): void {
  mockJobDurationMs = durationMs
}

// Simulate job progression over time
function getJobProgress(job: MockJob): MockJob {
  const elapsed = (Date.now() - job.createdAt) / 1000
  const duration = mockJobDurationMs / 1000 // Convert to seconds

  if (job.status === 'completed' || job.status === 'failed') {
    return job
  }

  // Progress through stages based on elapsed time relative to configured duration
  // Stages: 20% loading, 40% inference, 30% processing, 10% finalizing
  const progress20 = duration * 0.2
  const progress60 = duration * 0.6
  const progress90 = duration * 0.9

  if (elapsed < progress20) {
    return { ...job, status: 'running', progress: 10, progressMessage: 'Loading case data...', elapsedSeconds: elapsed }
  } else if (elapsed < progress60) {
    return { ...job, status: 'running', progress: 30, progressMessage: 'Running DeepISLES inference...', elapsedSeconds: elapsed }
  } else if (elapsed < progress90) {
    return { ...job, status: 'running', progress: 70, progressMessage: 'Processing results...', elapsedSeconds: elapsed }
  } else if (elapsed < duration) {
    return { ...job, status: 'running', progress: 90, progressMessage: 'Computing metrics...', elapsedSeconds: elapsed }
  } else {
    // Job complete
    return { ...job, status: 'completed', progress: 100, progressMessage: 'Segmentation complete', elapsedSeconds: elapsed }
  }
}

export const handlers = [
  // GET /api/cases - List available cases
  http.get(`${API_BASE}/api/cases`, async () => {
    await delay(100)
    return HttpResponse.json({
      cases: ['sub-stroke0001', 'sub-stroke0002', 'sub-stroke0003'],
    })
  }),

  // POST /api/segment - Create segmentation job (returns immediately)
  http.post(`${API_BASE}/api/segment`, async ({ request }) => {
    const body = (await request.json()) as { case_id: string; fast_mode?: boolean }
    await delay(50) // Small delay to simulate network

    // Create a new job
    const jobId = `mock-${++jobCounter}`
    const job: MockJob = {
      id: jobId,
      caseId: body.case_id,
      status: 'pending',
      progress: 0,
      progressMessage: 'Job queued',
      elapsedSeconds: 0,
      fastMode: body.fast_mode !== false,
      createdAt: Date.now(),
    }
    mockJobs.set(jobId, job)

    // Return 202 Accepted with job ID
    return HttpResponse.json(
      {
        jobId: jobId,
        status: 'pending',
        message: `Segmentation job queued for ${body.case_id}`,
      },
      { status: 202 }
    )
  }),

  // GET /api/jobs/:jobId - Get job status
  http.get(`${API_BASE}/api/jobs/:jobId`, async ({ params }) => {
    const jobId = params.jobId as string
    await delay(50) // Small delay to simulate network

    const job = mockJobs.get(jobId)
    if (!job) {
      return HttpResponse.json(
        { detail: `Job not found: ${jobId}. Jobs expire after 1 hour.` },
        { status: 404 }
      )
    }

    // Update job progress based on elapsed time
    const updatedJob = getJobProgress(job)
    mockJobs.set(jobId, updatedJob)

    // Build response
    const response: Record<string, unknown> = {
      jobId: updatedJob.id,
      status: updatedJob.status,
      progress: updatedJob.progress,
      progressMessage: updatedJob.progressMessage,
      elapsedSeconds: Math.round(updatedJob.elapsedSeconds * 100) / 100,
    }

    // Include result if completed
    if (updatedJob.status === 'completed') {
      response.result = {
        caseId: updatedJob.caseId,
        diceScore: 0.847,
        volumeMl: 15.32,
        elapsedSeconds: updatedJob.fastMode ? 12.5 : 45.0,
        dwiUrl: `${API_BASE}/files/${jobId}/${updatedJob.caseId}/dwi.nii.gz`,
        predictionUrl: `${API_BASE}/files/${jobId}/${updatedJob.caseId}/prediction.nii.gz`,
      }
    }

    return HttpResponse.json(response)
  }),
]

// Error handlers for testing error states
export const errorHandlers = {
  casesServerError: http.get(`${API_BASE}/api/cases`, () => {
    return HttpResponse.json(
      { detail: 'Internal server error' },
      { status: 500 }
    )
  }),

  casesNetworkError: http.get(`${API_BASE}/api/cases`, () => {
    return HttpResponse.error()
  }),

  segmentCreateError: http.post(`${API_BASE}/api/segment`, () => {
    return HttpResponse.json(
      { detail: 'Failed to create job: case not found' },
      { status: 400 }
    )
  }),

  jobNotFound: http.get(`${API_BASE}/api/jobs/:jobId`, () => {
    return HttpResponse.json(
      { detail: 'Job not found or expired' },
      { status: 404 }
    )
  }),

  // Simulate a job that fails during processing
  jobFailed: [
    http.post(`${API_BASE}/api/segment`, async ({ request }) => {
      const body = (await request.json()) as { case_id: string }
      const jobId = `fail-${++jobCounter}`
      mockJobs.set(jobId, {
        id: jobId,
        caseId: body.case_id,
        status: 'failed',
        progress: 30,
        progressMessage: 'Error occurred',
        elapsedSeconds: 5.2,
        fastMode: true,
        createdAt: Date.now(),
      })
      return HttpResponse.json(
        { jobId, status: 'pending', message: 'Job queued' },
        { status: 202 }
      )
    }),
    http.get(`${API_BASE}/api/jobs/:jobId`, ({ params }) => {
      const jobId = params.jobId as string
      const job = mockJobs.get(jobId)
      if (!job) {
        return HttpResponse.json({ detail: 'Not found' }, { status: 404 })
      }
      return HttpResponse.json({
        jobId: job.id,
        status: 'failed',
        progress: 30,
        progressMessage: 'Error occurred',
        elapsedSeconds: 5.2,
        error: 'Segmentation failed: out of memory',
      })
    }),
  ],
}