package scheduler

import (
	"path/filepath"
	"testing"

	"pete/internal/config"
	"pete/internal/poster"
	"pete/internal/storage"
)

type fakeQueue struct {
	items []poster.QueueItem
}

func (f *fakeQueue) Enqueue(item poster.QueueItem) {
	f.items = append(f.items, item)
}

func setupTestDB(t *testing.T) {
	t.Helper()
	dbPath := filepath.Join(t.TempDir(), "test.db")
	if err := storage.Init(dbPath); err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { storage.Close() })
}

func insertPostable(t *testing.T, guid, source, channel string, seenAt int64) {
	t.Helper()
	if err := storage.InsertStory(&storage.Story{
		GUID:       guid,
		Headline:   "Headline for " + guid,
		Lede:       "Lede for " + guid,
		ArticleURL: "https://example.com/" + guid,
		Source:     source,
		FeedHint:   "tech",
		SeenAt:     seenAt,
	}); err != nil {
		t.Fatalf("InsertStory(%s): %v", guid, err)
	}
	storage.MarkClassified(guid, channel, "[]")
}

func sources(names ...string) []config.SourceConfig {
	out := make([]config.SourceConfig, len(names))
	for i, n := range names {
		out[i] = config.SourceConfig{
			Name:                n,
			FeedURL:             "https://example.com/" + n,
			Tier:                1,
			PollIntervalMinutes: 20,
			Enabled:             true,
		}
	}
	return out
}

func TestNew_FiltersDisabledSources(t *testing.T) {
	srcs := []config.SourceConfig{
		{Name: "A", Enabled: true},
		{Name: "B", Enabled: false},
		{Name: "C", Enabled: true},
	}
	rr := New(srcs, 4, &fakeQueue{})
	if rr == nil {
		t.Fatal("expected non-nil RoundRobin")
	}
	if len(rr.sources) != 2 || rr.sources[0].Name != "A" || rr.sources[1].Name != "C" {
		t.Errorf("expected [A,C], got %v", rr.sources)
	}
}

func TestNew_NoEnabledSources_ReturnsNil(t *testing.T) {
	srcs := []config.SourceConfig{{Name: "A", Enabled: false}}
	if New(srcs, 4, &fakeQueue{}) != nil {
		t.Error("expected nil when no sources are enabled")
	}
}

func TestTick_PicksNewestPostableFromFirstSource(t *testing.T) {
	setupTestDB(t)
	insertPostable(t, "a-old", "A", "tech", 100)
	insertPostable(t, "a-new", "A", "tech", 200)
	insertPostable(t, "b-1", "B", "politics", 150)

	fq := &fakeQueue{}
	rr := New(sources("A", "B"), 4, fq)
	rr.tick()

	if len(fq.items) != 1 {
		t.Fatalf("expected 1 enqueued, got %d", len(fq.items))
	}
	if fq.items[0].GUID != "a-new" {
		t.Errorf("expected newest from A (a-new), got %s", fq.items[0].GUID)
	}
	lastSource, _, _ := storage.GetRoundRobinState()
	if lastSource != "A" {
		t.Errorf("expected last_source=A, got %s", lastSource)
	}
}

func TestTick_SkipsEmptyAndAdvancesPointer(t *testing.T) {
	setupTestDB(t)
	// Pretend we just posted from A; next tick should start at B, which is
	// empty, so it should skip to C.
	storage.SetRoundRobinState("A", 0)
	insertPostable(t, "c-1", "C", "tech", 100)

	fq := &fakeQueue{}
	rr := New(sources("A", "B", "C"), 4, fq)
	rr.tick()

	if len(fq.items) != 1 || fq.items[0].GUID != "c-1" {
		t.Fatalf("expected c-1 to be enqueued, got %+v", fq.items)
	}
	lastSource, _, _ := storage.GetRoundRobinState()
	if lastSource != "C" {
		t.Errorf("expected last_source=C after skipping B, got %s", lastSource)
	}
}

func TestTick_NothingPostable_LeavesPointerUnchanged(t *testing.T) {
	setupTestDB(t)
	storage.SetRoundRobinState("A", 1000)

	fq := &fakeQueue{}
	rr := New(sources("A", "B"), 4, fq)
	rr.tick()

	if len(fq.items) != 0 {
		t.Fatalf("expected 0 enqueued, got %d", len(fq.items))
	}
	lastSource, lastTickAt, _ := storage.GetRoundRobinState()
	if lastSource != "A" {
		t.Errorf("expected last_source unchanged=A, got %s", lastSource)
	}
	if lastTickAt <= 1000 {
		t.Errorf("expected last_tick_at to advance past 1000, got %d", lastTickAt)
	}
}

func TestTick_WrapsAroundFromLastSource(t *testing.T) {
	setupTestDB(t)
	// last_source = C means next tick starts at A (wraparound).
	storage.SetRoundRobinState("C", 0)
	insertPostable(t, "a-1", "A", "tech", 100)
	insertPostable(t, "c-1", "C", "tech", 200) // C is newer, but rotation must pick A

	fq := &fakeQueue{}
	rr := New(sources("A", "B", "C"), 4, fq)
	rr.tick()

	if len(fq.items) != 1 || fq.items[0].GUID != "a-1" {
		t.Fatalf("expected a-1 (wraparound), got %+v", fq.items)
	}
}

func TestTick_DiscardedAndDuplicateExcluded(t *testing.T) {
	setupTestDB(t)
	insertPostable(t, "a-discard", "A", "_discarded", 200) // sentinel
	insertPostable(t, "a-dup", "A", "_duplicate", 150)     // sentinel
	insertPostable(t, "a-real", "A", "tech", 100)          // older but only real one

	fq := &fakeQueue{}
	rr := New(sources("A"), 4, fq)
	rr.tick()

	if len(fq.items) != 1 || fq.items[0].GUID != "a-real" {
		t.Fatalf("expected a-real (sentinels excluded), got %+v", fq.items)
	}
}

func TestTick_AlreadyPostedExcluded(t *testing.T) {
	setupTestDB(t)
	insertPostable(t, "a-posted", "A", "tech", 200)
	insertPostable(t, "a-fresh", "A", "tech", 100)
	storage.InsertPostLog("a-posted", "tech", "$evt1", "https://example.com/a-posted")

	fq := &fakeQueue{}
	rr := New(sources("A"), 4, fq)
	rr.tick()

	if len(fq.items) != 1 || fq.items[0].GUID != "a-fresh" {
		t.Fatalf("expected a-fresh (a-posted already in post_log), got %+v", fq.items)
	}
}

func TestTick_UnknownLastSource_StartsAtIndexZero(t *testing.T) {
	setupTestDB(t)
	// Stale state pointing at a source no longer in config.
	storage.SetRoundRobinState("RetiredSource", 0)
	insertPostable(t, "a-1", "A", "tech", 100)
	insertPostable(t, "b-1", "B", "tech", 200)

	fq := &fakeQueue{}
	rr := New(sources("A", "B"), 4, fq)
	rr.tick()

	if len(fq.items) != 1 || fq.items[0].GUID != "a-1" {
		t.Fatalf("expected a-1 (start at idx 0 when last_source unknown), got %+v", fq.items)
	}
}