package model_test

import (
	"fmt"
	"sort"
	"sync"
	"time"

	"github.com/mudler/LocalAI/pkg/model"
	. "github.com/onsi/ginkgo/v2"
	. "github.com/onsi/gomega"
)

var _ = Describe("BackendLogStore", func() {
	var s *model.BackendLogStore

	BeforeEach(func() {
		s = model.NewBackendLogStore(100)
	})

	// Pins the multi-replica behavior added when the worker's process key
	// changed from `modelID` to `modelID#replicaIndex`. The frontend still
	// asks for logs of `qwen3-0.6b`, but the actual buffers live under
	// `qwen3-0.6b#0` and `qwen3-0.6b#1` — without aggregation, operators
	// see no logs in distributed mode.
	Describe("GetLines", func() {
		It("aggregates lines across replicas when called with a bare model ID", func() {
			// Two replicas of the same model, plus a different model that should
			// never leak in. AppendLine timestamps via time.Now(), so add small
			// sleeps so the merged order is deterministic.
			s.AppendLine("qwen3-0.6b#0", "stderr", "r0-line-1")
			time.Sleep(2 * time.Millisecond)
			s.AppendLine("qwen3-0.6b#1", "stderr", "r1-line-1")
			time.Sleep(2 * time.Millisecond)
			s.AppendLine("qwen3-0.6b#0", "stdout", "r0-line-2")
			time.Sleep(2 * time.Millisecond)
			s.AppendLine("other-model#0", "stderr", "should-not-appear")

			texts := []string{}
			for _, l := range s.GetLines("qwen3-0.6b") {
				texts = append(texts, l.Text)
			}
			Expect(texts).To(Equal([]string{"r0-line-1", "r1-line-1", "r0-line-2"}))
		})

		It("returns only the matching replica when called with a full process key", func() {
			s.AppendLine("qwen3-0.6b#0", "stderr", "r0-line-1")
			s.AppendLine("qwen3-0.6b#1", "stderr", "r1-line-1")
			s.AppendLine("qwen3-0.6b#0", "stdout", "r0-line-2")

			lines := s.GetLines("qwen3-0.6b#0")
			Expect(lines).To(HaveLen(2))
			for _, l := range lines {
				Expect(l.Text).NotTo(Equal("r1-line-1"), "replica 0 must not include replica 1's lines")
			}
		})

		It("returns an empty slice for an unknown model", func() {
			Expect(s.GetLines("never-loaded-model")).To(BeEmpty())
		})
	})

	// Confirms the /v1/backend-logs listing shows one entry per model, not
	// one per replica — operators don't think about replica indexes; they
	// pick a model.
	Describe("ListModels", func() {
		It("dedupes replicas and keeps non-replica suffixes intact", func() {
			s.AppendLine("model-a#0", "stderr", "x")
			s.AppendLine("model-a#1", "stderr", "y")
			s.AppendLine("model-b#0", "stderr", "z")
			s.AppendLine("model-c", "stderr", "no-replica-suffix") // back-compat for non-distributed

			got := s.ListModels()
			sort.Strings(got)
			Expect(got).To(Equal([]string{"model-a", "model-b", "model-c"}))
		})
	})

	Describe("Subscribe", func() {
		// Confirms the WebSocket streaming path (the live tail UI) receives
		// lines from every replica when the caller subscribes by bare modelID.
		It("aggregates live lines across replicas", func() {
			// Pre-create both replica buffers so Subscribe can find them.
			s.AppendLine("model-a#0", "stderr", "preload-r0")
			s.AppendLine("model-a#1", "stderr", "preload-r1")

			ch, unsubscribe := s.Subscribe("model-a")
			defer unsubscribe()

			// Emit one line per replica after subscribing.
			s.AppendLine("model-a#0", "stderr", "live-r0")
			s.AppendLine("model-a#1", "stderr", "live-r1")
			// Different model — must not appear.
			s.AppendLine("model-b#0", "stderr", "leak-check")

			seen := map[string]bool{}
			deadline := time.After(500 * time.Millisecond)
			for len(seen) < 2 {
				select {
				case line, ok := <-ch:
					Expect(ok).To(BeTrue(), "subscribe channel closed early; saw %v", seen)
					seen[line.Text] = true
					Expect(line.Text).NotTo(Equal("leak-check"), "subscribe leaked a line from a different model")
				case <-deadline:
					Fail(fmt.Sprintf("timed out waiting for fan-in lines; saw %v", seen))
				}
			}
			Expect(seen).To(HaveKey("live-r0"))
			Expect(seen).To(HaveKey("live-r1"))
		})

		// Pins that callers passing the full process key get only that
		// replica — useful for a future per-replica logs view.
		It("filters to a single replica when called with a full process key", func() {
			ch, unsubscribe := s.Subscribe("model-a#0")
			defer unsubscribe()

			s.AppendLine("model-a#0", "stderr", "wanted")
			s.AppendLine("model-a#1", "stderr", "unwanted")

			select {
			case line := <-ch:
				Expect(line.Text).To(Equal("wanted"))
			case <-time.After(500 * time.Millisecond):
				Fail("no line received from replica-scoped subscription")
			}

			// Drain quickly: confirm replica 1 didn't leak in.
			select {
			case line := <-ch:
				Fail(fmt.Sprintf("replica-scoped sub leaked line from replica 1: %q", line.Text))
			case <-time.After(50 * time.Millisecond):
			}
		})

		// Pins the panic CI hit: the aggregated fan-in goroutine sending
		// on the merged channel raced with unsubscribe closing it. Hammer
		// AppendLine concurrently with Subscribe + unsubscribe + Remove
		// to make sure neither "send on closed channel" nor "close of
		// closed channel" panics can resurface. The race detector should
		// catch any regression.
		It("survives concurrent unsubscribe and Remove without panicking", func() {
			// Pre-create replica buffers so Subscribe finds them.
			for r := 0; r < 3; r++ {
				s.AppendLine(fmt.Sprintf("model-x#%d", r), "stderr", "preload")
			}

			stop := make(chan struct{})
			var wg sync.WaitGroup

			// Writers — keep the per-buffer channels under constant pressure.
			for r := 0; r < 3; r++ {
				wg.Add(1)
				go func(r int) {
					defer wg.Done()
					id := fmt.Sprintf("model-x#%d", r)
					for {
						select {
						case <-stop:
							return
						default:
							s.AppendLine(id, "stderr", "burst")
						}
					}
				}(r)
			}

			// Subscribers — repeatedly Subscribe and unsubscribe while writers run.
			for w := 0; w < 4; w++ {
				wg.Add(1)
				go func() {
					defer wg.Done()
					for i := 0; i < 200; i++ {
						ch, unsubscribe := s.Subscribe("model-x")
						// Drain a couple of lines, then unsubscribe.
						select {
						case <-ch:
						case <-time.After(2 * time.Millisecond):
						}
						unsubscribe()
					}
				}()
			}

			// Buffer reaper — exercises the Remove path while subscribers are live.
			wg.Add(1)
			go func() {
				defer wg.Done()
				for i := 0; i < 50; i++ {
					s.Remove("model-x#0")
					s.AppendLine("model-x#0", "stderr", "respawn")
					time.Sleep(time.Millisecond)
				}
			}()

			time.Sleep(150 * time.Millisecond)
			close(stop)
			wg.Wait()
		})
	})
})