import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
import { setActivePinia, createPinia } from 'pinia'
import { useSystemActivityStore } from '../src/stores/systemActivity.js'

// Milestone 422 step 4. Covers the store half of the worker-lane dial — the
// part that decides what the card can tell the operator.
//
// The distinction being protected: a change that was STORED but not pushed
// (`applied: false`, because the lane is restarting) is not a failure, and a
// REFUSED value (400) is. Collapsing those two into one message is how a
// control stops being trustworthy — one invites waiting, the other invites
// changing what you asked for.

function stubFetch(handler) {
  globalThis.fetch = vi.fn(async (url, init) => {
    const { status, body } = handler(url, init)
    return {
      ok: status >= 200 && status < 300,
      status,
      statusText: String(status),
      text: async () => (body == null ? '' : JSON.stringify(body)),
    }
  })
}

const LANES_BODY = {
  lanes: [
    {
      name: 'worker', display_name: 'Worker',
      queues: ['default', 'import', 'thumbnail', 'download'],
      slots: 1, slots_cap: 4, ceiling: 8, enabled: true, memory_bound: false,
      live: { present: true, replicas: 1, pool: 1, active: 0, reserved: 3 },
      queue_depth: 5, pending: 8,
    },
    {
      name: 'ml', display_name: 'ML tagging', queues: ['ml'],
      slots: 0, slots_cap: 1, ceiling: 2, enabled: false, memory_bound: true,
      live: { present: false, replicas: 0, pool: null, active: 0, reserved: 0 },
      queue_depth: null, pending: null,
    },
  ],
  fetched_at: '2026-09-22T12:00:00Z',
}

describe('worker lanes store', () => {
  beforeEach(() => setActivePinia(createPinia()))
  afterEach(() => vi.restoreAllMocks())

  it('loads the lanes', async () => {
    stubFetch(() => ({ status: 200, body: LANES_BODY }))
    const s = useSystemActivityStore()
    await s.loadLanes()
    expect(s.lanes.lanes.map((l) => l.name)).toEqual(['worker', 'ml'])
  })

  it('a load failure records the error rather than throwing at the caller', async () => {
    // The card polls this every 3s. An unhandled rejection per tick would
    // drown the console and stop the other pollers in the same function.
    stubFetch(() => ({ status: 500, body: { error: 'boom' } }))
    const s = useSystemActivityStore()
    await expect(s.loadLanes()).resolves.toBeUndefined()
    expect(s.lastError).toBeTruthy()
  })

  it('setLane posts only the fields it was given', async () => {
    // Partial update: the stepper sends slots without restating a cap it did
    // not touch. Sending the whole row back would make two operators editing
    // different fields clobber each other.
    const calls = []
    stubFetch((url, init) => {
      calls.push({ url, init })
      if (init?.method === 'POST') {
        return { status: 200, body: { name: 'worker', slots: 2, applied: true } }
      }
      return { status: 200, body: LANES_BODY }
    })
    const s = useSystemActivityStore()
    await s.setLane('worker', { slots: 2 })

    const post = calls.find((c) => c.init?.method === 'POST')
    expect(post.url).toContain('/api/system/workers/worker')
    expect(JSON.parse(post.init.body)).toEqual({ slots: 2 })
  })

  it('setLane refetches so the card shows the server truth, not the guess', async () => {
    // The reply is one lane; the card renders all of them plus live pool and
    // pending. Patching the local row from the reply would leave every other
    // column stale and eventually wrong.
    let gets = 0
    stubFetch((url, init) => {
      if (init?.method === 'POST') return { status: 200, body: { applied: true } }
      gets += 1
      return { status: 200, body: LANES_BODY }
    })
    const s = useSystemActivityStore()
    await s.setLane('worker', { slots: 2 })
    expect(gets).toBe(1)
  })

  it('a stored-but-unapplied change comes back as applied:false, not an error', async () => {
    // The lane is restarting. The value IS saved and the reconcile will carry
    // it — so this must reach the card as information, not as a failure that
    // invites the operator to set it again.
    stubFetch((url, init) => {
      if (init?.method === 'POST') {
        return {
          status: 200,
          body: { applied: false, apply_error: 'lane is not running', slots: 2 },
        }
      }
      return { status: 200, body: LANES_BODY }
    })
    const s = useSystemActivityStore()
    const reply = await s.setLane('worker', { slots: 2 })
    expect(reply.applied).toBe(false)
    expect(reply.apply_error).toContain('not running')
  })

  it('a refused value throws so the card can show the reason', async () => {
    // Deliberately NOT swallowed. The detail is written to be read by a person
    // ("above what this container can hold"), and a control that silently does
    // nothing is worse than one that refuses out loud.
    stubFetch((url, init) => {
      if (init?.method === 'POST') {
        return {
          status: 400,
          body: { error: 'refused', detail: 'cap 10000 is above what this container can hold (2 for ML tagging)' },
        }
      }
      return { status: 200, body: LANES_BODY }
    })
    const s = useSystemActivityStore()
    // Assert the REASON is reachable, not merely that it threw. `toThrow()`
    // alone passes whether the card can read the sentence or not — which is
    // how the first version of the card shipped reading `e.detail` (always
    // undefined) and would have shown the operator the bare word "refused".
    const err = await s.setLane('ml', { slots_cap: 10000 }).catch((e) => e)
    expect(err.status).toBe(400)
    expect(err.body.detail).toContain('container can hold')
  })
})