package trim

import (
	"strings"
	"testing"

	"gitea.maximumdirect.net/eric/seriatim/schema"
)

func TestApplyKeepModeRenumbersFromOne(t *testing.T) {
	input := fullTranscriptFixture()
	selector := mustParseSelector(t, "2,4")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if len(result.Transcript.Segments) != 2 {
		t.Fatalf("segment count = %d, want 2", len(result.Transcript.Segments))
	}
	assertSegmentIDs(t, result.Transcript.Segments, []int{1, 2})
	assertSegmentTexts(t, result.Transcript.Segments, []string{"beta", "delta"})
	assertIntMap(t, result.OldToNewID, map[int]int{2: 1, 4: 2})
	assertIntSlice(t, result.RemovedIDs, []int{1, 3})
}

func TestApplyRemoveModeRenumbersFromOne(t *testing.T) {
	input := fullTranscriptFixture()
	selector := mustParseSelector(t, "2,4")

	result, err := Apply(input, Options{
		Mode:     ModeRemove,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	assertSegmentIDs(t, result.Transcript.Segments, []int{1, 2})
	assertSegmentTexts(t, result.Transcript.Segments, []string{"alpha", "gamma"})
	assertIntMap(t, result.OldToNewID, map[int]int{1: 1, 3: 2})
	assertIntSlice(t, result.RemovedIDs, []int{2, 4})
}

func TestApplySelectorOrderDoesNotChangeTranscriptOrder(t *testing.T) {
	input := fullTranscriptFixture()
	selector := mustParseSelector(t, "4,1,3")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	assertSegmentIDs(t, result.Transcript.Segments, []int{1, 2, 3})
	assertSegmentTexts(t, result.Transcript.Segments, []string{"alpha", "gamma", "delta"})
}

func TestApplyFailsWhenSelectedIDDoesNotExist(t *testing.T) {
	input := fullTranscriptFixture()
	selector := mustParseSelector(t, "2,99")

	_, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err == nil {
		t.Fatal("expected missing selected ID error")
	}
	if !strings.Contains(err.Error(), "does not exist") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestApplyFailsOnDuplicateInputIDs(t *testing.T) {
	input := fullTranscriptFixture()
	input.Segments[2].ID = 2
	selector := mustParseSelector(t, "2")

	_, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err == nil {
		t.Fatal("expected duplicate input ID error")
	}
	if !strings.Contains(err.Error(), "duplicate segment ID") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestApplyFailsOnMissingOrNonSequentialInputIDs(t *testing.T) {
	input := fullTranscriptFixture()
	input.Segments[1].ID = 5
	selector := mustParseSelector(t, "1")

	_, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err == nil {
		t.Fatal("expected non-sequential input ID error")
	}
	if !strings.Contains(err.Error(), "must be sequential") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestApplyFailsOnNonPositiveInputIDs(t *testing.T) {
	input := fullTranscriptFixture()
	input.Segments[0].ID = 0
	selector := mustParseSelector(t, "1")

	_, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err == nil {
		t.Fatal("expected non-positive input ID error")
	}
	if !strings.Contains(err.Error(), "non-positive") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestApplyEmptyOutputFailsUnlessAllowEmpty(t *testing.T) {
	input := fullTranscriptFixture()
	selector := mustParseSelector(t, "1-4")

	_, err := Apply(input, Options{
		Mode:     ModeRemove,
		Selector: selector,
	})
	if err == nil {
		t.Fatal("expected empty-output error")
	}
	if !strings.Contains(err.Error(), "empty transcript") {
		t.Fatalf("unexpected error: %v", err)
	}

	allowed, err := Apply(input, Options{
		Mode:       ModeRemove,
		Selector:   selector,
		AllowEmpty: true,
	})
	if err != nil {
		t.Fatalf("apply with AllowEmpty failed: %v", err)
	}
	if len(allowed.Transcript.Segments) != 0 {
		t.Fatalf("segment count = %d, want 0", len(allowed.Transcript.Segments))
	}
	assertIntMap(t, allowed.OldToNewID, map[int]int{})
	assertIntSlice(t, allowed.RemovedIDs, []int{1, 2, 3, 4})
}

func TestApplyPreservesRetainedSegmentFieldsAndClearsOverlapIDs(t *testing.T) {
	input := fullTranscriptFixture()
	selector := mustParseSelector(t, "2")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if len(result.Transcript.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(result.Transcript.Segments))
	}
	segment := result.Transcript.Segments[0]
	if segment.ID != 1 {
		t.Fatalf("segment ID = %d, want 1", segment.ID)
	}
	if segment.Source != "b.json" {
		t.Fatalf("source = %q, want %q", segment.Source, "b.json")
	}
	if segment.SourceSegmentIndex == nil || *segment.SourceSegmentIndex != 20 {
		t.Fatalf("source_segment_index = %v, want 20", segment.SourceSegmentIndex)
	}
	if segment.SourceRef != "b.json#20" {
		t.Fatalf("source_ref = %q, want %q", segment.SourceRef, "b.json#20")
	}
	if !equalStringSlices(segment.DerivedFrom, []string{"b.json#19", "b.json#20"}) {
		t.Fatalf("derived_from = %v, want %v", segment.DerivedFrom, []string{"b.json#19", "b.json#20"})
	}
	if !equalStringSlices(segment.Categories, []string{"filler", "backchannel"}) {
		t.Fatalf("categories = %v, want %v", segment.Categories, []string{"filler", "backchannel"})
	}
	if segment.Speaker != "Bob" {
		t.Fatalf("speaker = %q, want Bob", segment.Speaker)
	}
	if segment.Start != 2 || segment.End != 3 {
		t.Fatalf("times = %.3f-%.3f, want 2.000-3.000", segment.Start, segment.End)
	}
	if segment.Text != "beta" {
		t.Fatalf("text = %q, want beta", segment.Text)
	}
	if segment.OverlapGroupID != 0 {
		t.Fatalf("overlap_group_id = %d, want 0", segment.OverlapGroupID)
	}
	if len(result.Transcript.OverlapGroups) != 0 {
		t.Fatalf("overlap_groups count = %d, want 0", len(result.Transcript.OverlapGroups))
	}
}

func TestApplyFullSchemaRemovesStaleOverlapGroups(t *testing.T) {
	input := overlapTranscriptFixture()
	selector := mustParseSelector(t, "1,3")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if len(result.Transcript.OverlapGroups) != 0 {
		t.Fatalf("overlap_groups count = %d, want 0", len(result.Transcript.OverlapGroups))
	}
	for index, segment := range result.Transcript.Segments {
		if segment.OverlapGroupID != 0 {
			t.Fatalf("segment %d overlap_group_id = %d, want 0", index, segment.OverlapGroupID)
		}
	}
}

func TestApplyFullSchemaRecomputesOverlapGroup(t *testing.T) {
	input := overlapTranscriptFixture()
	selector := mustParseSelector(t, "1,2")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	assertSegmentIDs(t, result.Transcript.Segments, []int{1, 2})
	assertIntSlice(t, []int{
		result.Transcript.Segments[0].OverlapGroupID,
		result.Transcript.Segments[1].OverlapGroupID,
	}, []int{1, 1})
	if len(result.Transcript.OverlapGroups) != 1 {
		t.Fatalf("overlap_groups count = %d, want 1", len(result.Transcript.OverlapGroups))
	}
	group := result.Transcript.OverlapGroups[0]
	if group.ID != 1 {
		t.Fatalf("group ID = %d, want 1", group.ID)
	}
	if group.Start != 1 || group.End != 4 {
		t.Fatalf("group times = %.3f-%.3f, want 1.000-4.000", group.Start, group.End)
	}
	if !equalStringSlices(group.Segments, []string{"a.json#10", "b.json#20"}) {
		t.Fatalf("group segments = %v, want %v", group.Segments, []string{"a.json#10", "b.json#20"})
	}
	if !equalStringSlices(group.Speakers, []string{"Alice", "Bob"}) {
		t.Fatalf("group speakers = %v, want %v", group.Speakers, []string{"Alice", "Bob"})
	}
}

func TestApplyFullSchemaDropsGroupWhenFewerThanTwoSpeakersRemain(t *testing.T) {
	input := overlapTranscriptFixture()
	selector := mustParseSelector(t, "1")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if len(result.Transcript.OverlapGroups) != 0 {
		t.Fatalf("overlap_groups count = %d, want 0", len(result.Transcript.OverlapGroups))
	}
	if len(result.Transcript.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(result.Transcript.Segments))
	}
	if result.Transcript.Segments[0].OverlapGroupID != 0 {
		t.Fatalf("segment overlap_group_id = %d, want 0", result.Transcript.Segments[0].OverlapGroupID)
	}
}

func TestApplyFullSchemaHandlesTransitiveOverlaps(t *testing.T) {
	input := transitiveOverlapFixture()
	selector := mustParseSelector(t, "1-3")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if len(result.Transcript.OverlapGroups) != 1 {
		t.Fatalf("overlap_groups count = %d, want 1", len(result.Transcript.OverlapGroups))
	}
	assertIntSlice(t, []int{
		result.Transcript.Segments[0].OverlapGroupID,
		result.Transcript.Segments[1].OverlapGroupID,
		result.Transcript.Segments[2].OverlapGroupID,
	}, []int{1, 1, 1})
	group := result.Transcript.OverlapGroups[0]
	if group.Start != 10 || group.End != 15 {
		t.Fatalf("group times = %.3f-%.3f, want 10.000-15.000", group.Start, group.End)
	}
}

func TestApplyFullSchemaBoundaryTouchingNotGrouped(t *testing.T) {
	input := boundaryFixture()
	selector := mustParseSelector(t, "1-2")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if len(result.Transcript.OverlapGroups) != 0 {
		t.Fatalf("overlap_groups count = %d, want 0", len(result.Transcript.OverlapGroups))
	}
	assertIntSlice(t, []int{
		result.Transcript.Segments[0].OverlapGroupID,
		result.Transcript.Segments[1].OverlapGroupID,
	}, []int{0, 0})
}

func TestApplyIntermediateDoesNotIncludeOverlapGroups(t *testing.T) {
	input := schema.IntermediateTranscript{
		Metadata: schema.IntermediateMetadata{
			Application:  "seriatim",
			Version:      "v-test",
			OutputSchema: "seriatim-intermediate",
		},
		Segments: []schema.IntermediateSegment{
			{ID: 1, Start: 1, End: 3, Speaker: "Alice", Text: "alpha", Categories: []string{"word-run"}},
			{ID: 2, Start: 2, End: 4, Speaker: "Bob", Text: "beta", Categories: []string{"filler"}},
		},
	}
	selector := mustParseSelector(t, "1")
	result, err := ApplyIntermediate(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply intermediate failed: %v", err)
	}
	if len(result.Transcript.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(result.Transcript.Segments))
	}
	if result.Transcript.Segments[0].ID != 1 {
		t.Fatalf("segment id = %d, want 1", result.Transcript.Segments[0].ID)
	}
	if err := schema.ValidateIntermediateTranscript(result.Transcript); err != nil {
		t.Fatalf("intermediate output should remain valid: %v", err)
	}
}

func TestApplyMinimalDoesNotIncludeOverlapGroups(t *testing.T) {
	input := schema.MinimalTranscript{
		Metadata: schema.MinimalMetadata{
			Application:  "seriatim",
			Version:      "v-test",
			OutputSchema: "seriatim-minimal",
		},
		Segments: []schema.MinimalSegment{
			{ID: 1, Start: 1, End: 3, Speaker: "Alice", Text: "alpha"},
			{ID: 2, Start: 2, End: 4, Speaker: "Bob", Text: "beta"},
		},
	}
	selector := mustParseSelector(t, "2")
	result, err := ApplyMinimal(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply minimal failed: %v", err)
	}
	if len(result.Transcript.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(result.Transcript.Segments))
	}
	if result.Transcript.Segments[0].ID != 1 {
		t.Fatalf("segment id = %d, want 1", result.Transcript.Segments[0].ID)
	}
	if err := schema.ValidateMinimalTranscript(result.Transcript); err != nil {
		t.Fatalf("minimal output should remain valid: %v", err)
	}
}

func TestApplyOutputInvariantsValidAfterRenumberAndOverlapRecompute(t *testing.T) {
	input := overlapTranscriptFixture()
	selector := mustParseSelector(t, "2,1")

	result, err := Apply(input, Options{
		Mode:     ModeKeep,
		Selector: selector,
	})
	if err != nil {
		t.Fatalf("apply failed: %v", err)
	}

	if err := schema.ValidateTranscript(result.Transcript); err != nil {
		t.Fatalf("trim output should remain valid: %v", err)
	}
}

func mustParseSelector(t *testing.T, value string) Selector {
	t.Helper()
	selector, err := ParseSelector(value)
	if err != nil {
		t.Fatalf("selector parse failed for %q: %v", value, err)
	}
	return selector
}

func fullTranscriptFixture() schema.Transcript {
	firstIndex := 10
	secondIndex := 20
	thirdIndex := 30
	fourthIndex := 40

	return schema.Transcript{
		Metadata: schema.Metadata{
			Application:           "seriatim",
			Version:               "v-test",
			InputReader:           "json-files",
			InputFiles:            []string{"a.json", "b.json"},
			PreprocessingModules:  []string{"validate-raw"},
			PostprocessingModules: []string{"detect-overlaps"},
			OutputModules:         []string{"json"},
		},
		Segments: []schema.Segment{
			{
				ID:                 1,
				Source:             "a.json",
				SourceSegmentIndex: &firstIndex,
				SourceRef:          "a.json#10",
				DerivedFrom:        []string{"a.json#10"},
				Speaker:            "Alice",
				Start:              1,
				End:                2,
				Text:               "alpha",
				Categories:         []string{"word-run"},
				OverlapGroupID:     7,
			},
			{
				ID:                 2,
				Source:             "b.json",
				SourceSegmentIndex: &secondIndex,
				SourceRef:          "b.json#20",
				DerivedFrom:        []string{"b.json#19", "b.json#20"},
				Speaker:            "Bob",
				Start:              2,
				End:                3,
				Text:               "beta",
				Categories:         []string{"filler", "backchannel"},
				OverlapGroupID:     7,
			},
			{
				ID:                 3,
				Source:             "c.json",
				SourceSegmentIndex: &thirdIndex,
				SourceRef:          "c.json#30",
				DerivedFrom:        []string{"c.json#30"},
				Speaker:            "Carol",
				Start:              3,
				End:                4,
				Text:               "gamma",
				Categories:         []string{"normal"},
				OverlapGroupID:     8,
			},
			{
				ID:                 4,
				Source:             "d.json",
				SourceSegmentIndex: &fourthIndex,
				SourceRef:          "d.json#40",
				DerivedFrom:        []string{"d.json#40"},
				Speaker:            "Dan",
				Start:              4,
				End:                5,
				Text:               "delta",
				Categories:         []string{"normal"},
				OverlapGroupID:     9,
			},
		},
		OverlapGroups: []schema.OverlapGroup{
			{
				ID:         7,
				Start:      1.5,
				End:        3.1,
				Segments:   []string{"a.json#10", "b.json#20"},
				Speakers:   []string{"Alice", "Bob"},
				Class:      "unknown",
				Resolution: "unresolved",
			},
		},
	}
}

func overlapTranscriptFixture() schema.Transcript {
	first := 10
	second := 20
	third := 30

	return schema.Transcript{
		Metadata: schema.Metadata{
			Application:           "seriatim",
			Version:               "v-test",
			InputReader:           "json-files",
			InputFiles:            []string{"a.json", "b.json", "c.json"},
			PreprocessingModules:  []string{"validate-raw"},
			PostprocessingModules: []string{"detect-overlaps"},
			OutputModules:         []string{"json"},
		},
		Segments: []schema.Segment{
			{
				ID:                 1,
				Source:             "a.json",
				SourceSegmentIndex: &first,
				SourceRef:          "a.json#10",
				Speaker:            "Alice",
				Start:              1,
				End:                4,
				Text:               "a",
				OverlapGroupID:     99,
			},
			{
				ID:                 2,
				Source:             "b.json",
				SourceSegmentIndex: &second,
				SourceRef:          "b.json#20",
				Speaker:            "Bob",
				Start:              2,
				End:                3,
				Text:               "b",
				OverlapGroupID:     99,
			},
			{
				ID:                 3,
				Source:             "c.json",
				SourceSegmentIndex: &third,
				SourceRef:          "c.json#30",
				Speaker:            "Carol",
				Start:              10,
				End:                11,
				Text:               "c",
				OverlapGroupID:     100,
			},
		},
		OverlapGroups: []schema.OverlapGroup{
			{
				ID:         99,
				Start:      0,
				End:        100,
				Segments:   []string{"stale#1", "stale#2"},
				Speakers:   []string{"stale"},
				Class:      "unknown",
				Resolution: "unresolved",
			},
		},
	}
}

func transitiveOverlapFixture() schema.Transcript {
	one := 1
	two := 2
	three := 3
	return schema.Transcript{
		Metadata: schema.Metadata{
			Application: "seriatim",
			Version:     "v-test",
		},
		Segments: []schema.Segment{
			{ID: 1, Source: "a.json", SourceSegmentIndex: &one, Speaker: "Alice", Start: 10, End: 14, Text: "a"},
			{ID: 2, Source: "b.json", SourceSegmentIndex: &two, Speaker: "Bob", Start: 12, End: 13, Text: "b"},
			{ID: 3, Source: "c.json", SourceSegmentIndex: &three, Speaker: "Carol", Start: 13.5, End: 15, Text: "c"},
		},
		OverlapGroups: []schema.OverlapGroup{{ID: 77}},
	}
}

func boundaryFixture() schema.Transcript {
	one := 1
	two := 2
	return schema.Transcript{
		Metadata: schema.Metadata{
			Application: "seriatim",
			Version:     "v-test",
		},
		Segments: []schema.Segment{
			{ID: 1, Source: "a.json", SourceSegmentIndex: &one, Speaker: "Alice", Start: 1, End: 2, Text: "a", OverlapGroupID: 7},
			{ID: 2, Source: "b.json", SourceSegmentIndex: &two, Speaker: "Bob", Start: 2, End: 3, Text: "b", OverlapGroupID: 7},
		},
		OverlapGroups: []schema.OverlapGroup{{ID: 7, Start: 1, End: 3}},
	}
}

func assertSegmentIDs(t *testing.T, segments []schema.Segment, want []int) {
	t.Helper()
	got := make([]int, len(segments))
	for index, segment := range segments {
		got[index] = segment.ID
	}
	assertIntSlice(t, got, want)
}

func assertSegmentTexts(t *testing.T, segments []schema.Segment, want []string) {
	t.Helper()
	got := make([]string, len(segments))
	for index, segment := range segments {
		got[index] = segment.Text
	}
	if !equalStringSlices(got, want) {
		t.Fatalf("segment texts = %v, want %v", got, want)
	}
}

func assertIntSlice(t *testing.T, got []int, want []int) {
	t.Helper()
	if len(got) != len(want) {
		t.Fatalf("slice length = %d, want %d", len(got), len(want))
	}
	for index := range got {
		if got[index] != want[index] {
			t.Fatalf("slice[%d] = %d, want %d (full got=%v, want=%v)", index, got[index], want[index], got, want)
		}
	}
}

func assertIntMap(t *testing.T, got map[int]int, want map[int]int) {
	t.Helper()
	if len(got) != len(want) {
		t.Fatalf("map length = %d, want %d", len(got), len(want))
	}
	for key, wantValue := range want {
		gotValue, exists := got[key]
		if !exists {
			t.Fatalf("missing map key %d", key)
		}
		if gotValue != wantValue {
			t.Fatalf("map[%d] = %d, want %d", key, gotValue, wantValue)
		}
	}
}

func equalStringSlices(got []string, want []string) bool {
	if len(got) != len(want) {
		return false
	}
	for index := range got {
		if got[index] != want[index] {
			return false
		}
	}
	return true
}