package overlap

import (
	"testing"

	"gitea.maximumdirect.net/eric/seriatim/internal/model"
)

func TestDetectNoOverlaps(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 2),
			segment("b.json", 0, "Bob", 2, 3),
		},
	}

	got := Detect(merged)
	if len(got.OverlapGroups) != 0 {
		t.Fatalf("expected no overlap groups, got %d", len(got.OverlapGroups))
	}
	assertNoSegmentAnnotations(t, got)
}

func TestDetectSimpleTwoSpeakerOverlap(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 3),
			segment("b.json", 0, "Bob", 2, 4),
		},
	}

	got := Detect(merged)
	assertGroup(t, got, 0, 1, 1, 4, []string{"a.json#0", "b.json#0"}, []string{"Alice", "Bob"})
	assertSegmentGroupIDs(t, got, []int{1, 1})
}

func TestDetectTransitiveOverlap(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 10, 14),
			segment("b.json", 0, "Bob", 12, 13),
			segment("c.json", 0, "Carol", 13.5, 15),
		},
	}

	got := Detect(merged)
	assertGroup(t, got, 0, 1, 10, 15, []string{"a.json#0", "b.json#0", "c.json#0"}, []string{"Alice", "Bob", "Carol"})
	assertSegmentGroupIDs(t, got, []int{1, 1, 1})
}

func TestDetectBoundaryContactDoesNotOverlap(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 2),
			segment("b.json", 0, "Bob", 2, 3),
		},
	}

	got := Detect(merged)
	if len(got.OverlapGroups) != 0 {
		t.Fatalf("expected no overlap groups, got %d", len(got.OverlapGroups))
	}
	assertNoSegmentAnnotations(t, got)
}

func TestDetectSameSpeakerOnlyOverlapDoesNotCreateGroup(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 3),
			segment("a.json", 1, "Alice", 2, 4),
		},
	}

	got := Detect(merged)
	if len(got.OverlapGroups) != 0 {
		t.Fatalf("expected no overlap groups, got %d", len(got.OverlapGroups))
	}
	assertNoSegmentAnnotations(t, got)
}

func TestDetectIncludesSameSpeakerSegmentInsideMultiSpeakerOverlap(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 5),
			segment("a.json", 1, "Alice", 2, 3),
			segment("b.json", 0, "Bob", 4, 6),
		},
	}

	got := Detect(merged)
	assertGroup(t, got, 0, 1, 1, 6, []string{"a.json#0", "a.json#1", "b.json#0"}, []string{"Alice", "Bob"})
	assertSegmentGroupIDs(t, got, []int{1, 1, 1})
}

func TestDetectMultipleGroups(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 3),
			segment("b.json", 0, "Bob", 2, 4),
			segment("c.json", 0, "Carol", 5, 7),
			segment("d.json", 0, "Dan", 6, 8),
		},
	}

	got := Detect(merged)
	if len(got.OverlapGroups) != 2 {
		t.Fatalf("group count = %d, want 2", len(got.OverlapGroups))
	}
	assertGroup(t, got, 0, 1, 1, 4, []string{"a.json#0", "b.json#0"}, []string{"Alice", "Bob"})
	assertGroup(t, got, 1, 2, 5, 8, []string{"c.json#0", "d.json#0"}, []string{"Carol", "Dan"})
	assertSegmentGroupIDs(t, got, []int{1, 1, 2, 2})
}

func TestDetectIsIdempotent(t *testing.T) {
	merged := model.MergedTranscript{
		Segments: []model.Segment{
			segment("a.json", 0, "Alice", 1, 3),
			segment("b.json", 0, "Bob", 2, 4),
		},
		OverlapGroups: []model.OverlapGroup{
			{ID: 99},
		},
	}
	merged.Segments[0].OverlapGroupID = 99

	once := Detect(merged)
	twice := Detect(once)
	assertGroup(t, twice, 0, 1, 1, 4, []string{"a.json#0", "b.json#0"}, []string{"Alice", "Bob"})
	assertSegmentGroupIDs(t, twice, []int{1, 1})
}

func segment(source string, sourceIndex int, speaker string, start float64, end float64) model.Segment {
	return model.Segment{
		Source:             source,
		SourceSegmentIndex: sourceIndex,
		Speaker:            speaker,
		Start:              start,
		End:                end,
		Text:               speaker,
	}
}

func assertGroup(t *testing.T, merged model.MergedTranscript, groupIndex int, id int, start float64, end float64, refs []string, speakers []string) {
	t.Helper()
	if len(merged.OverlapGroups) <= groupIndex {
		t.Fatalf("missing overlap group index %d", groupIndex)
	}
	group := merged.OverlapGroups[groupIndex]
	if group.ID != id {
		t.Fatalf("group ID = %d, want %d", group.ID, id)
	}
	if group.Start != start {
		t.Fatalf("group start = %f, want %f", group.Start, start)
	}
	if group.End != end {
		t.Fatalf("group end = %f, want %f", group.End, end)
	}
	if group.Class != "unknown" {
		t.Fatalf("group class = %q, want unknown", group.Class)
	}
	if group.Resolution != "unresolved" {
		t.Fatalf("group resolution = %q, want unresolved", group.Resolution)
	}
	if !equalStrings(group.Segments, refs) {
		t.Fatalf("group refs = %v, want %v", group.Segments, refs)
	}
	if !equalStrings(group.Speakers, speakers) {
		t.Fatalf("group speakers = %v, want %v", group.Speakers, speakers)
	}
}

func assertSegmentGroupIDs(t *testing.T, merged model.MergedTranscript, ids []int) {
	t.Helper()
	if len(merged.Segments) != len(ids) {
		t.Fatalf("segment count = %d, want %d", len(merged.Segments), len(ids))
	}
	for index, id := range ids {
		if merged.Segments[index].OverlapGroupID != id {
			t.Fatalf("segment %d overlap group ID = %d, want %d", index, merged.Segments[index].OverlapGroupID, id)
		}
	}
}

func assertNoSegmentAnnotations(t *testing.T, merged model.MergedTranscript) {
	t.Helper()
	for index, segment := range merged.Segments {
		if segment.OverlapGroupID != 0 {
			t.Fatalf("segment %d overlap group ID = %d, want 0", index, segment.OverlapGroupID)
		}
	}
}

func equalStrings(left []string, right []string) bool {
	if len(left) != len(right) {
		return false
	}
	for index := range left {
		if left[index] != right[index] {
			return false
		}
	}
	return true
}