package normalize

import (
	"strings"
	"testing"
)

func TestParseReaderObjectWithSegmentsParses(t *testing.T) {
	input := `{
		"segments": [
			{"start": 1.0, "end": 2.0, "speaker": " Alice ", "text": "hello", "id": 100}
		]
	}`

	parsed, err := ParseReader(strings.NewReader(input))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Shape != ShapeObjectWithSegments {
		t.Fatalf("shape = %q, want %q", parsed.Shape, ShapeObjectWithSegments)
	}
	if len(parsed.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(parsed.Segments))
	}
	segment := parsed.Segments[0]
	if segment.Speaker != "Alice" {
		t.Fatalf("speaker = %q, want %q", segment.Speaker, "Alice")
	}
	if segment.OriginalID == nil || *segment.OriginalID != 100 {
		t.Fatalf("original id = %v, want 100", segment.OriginalID)
	}
}

func TestParseReaderBareSegmentArrayParses(t *testing.T) {
	input := `[
		{"start": 1.0, "end": 2.0, "speaker": "Alice", "text": "hello"},
		{"start": 3.0, "end": 4.0, "speaker": "Bob", "text": "world"}
	]`

	parsed, err := ParseReader(strings.NewReader(input))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Shape != ShapeBareSegmentsArray {
		t.Fatalf("shape = %q, want %q", parsed.Shape, ShapeBareSegmentsArray)
	}
	if len(parsed.Segments) != 2 {
		t.Fatalf("segment count = %d, want 2", len(parsed.Segments))
	}
}

func TestParseReaderInvalidJSONFails(t *testing.T) {
	_, err := ParseReader(strings.NewReader(`{"segments":`))
	if err == nil {
		t.Fatal("expected parse error")
	}
	if !strings.Contains(err.Error(), "decode normalize input JSON") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestParseReaderObjectMissingSegmentsFails(t *testing.T) {
	_, err := ParseReader(strings.NewReader(`{"items":[]}`))
	if err == nil {
		t.Fatal("expected missing segments error")
	}
	if !strings.Contains(err.Error(), "must contain a \"segments\" field") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestParseReaderSegmentsNotArrayFails(t *testing.T) {
	_, err := ParseReader(strings.NewReader(`{"segments": {}}`))
	if err == nil {
		t.Fatal("expected segments not array error")
	}
	if !strings.Contains(err.Error(), "\"segments\" must be an array") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestParseReaderTopLevelScalarShapesFail(t *testing.T) {
	tests := []string{`"text"`, `42`, `null`, `true`}
	for _, input := range tests {
		_, err := ParseReader(strings.NewReader(input))
		if err == nil {
			t.Fatalf("expected top-level shape error for %s", input)
		}
		if !strings.Contains(err.Error(), "top-level object") {
			t.Fatalf("unexpected error for %s: %v", input, err)
		}
	}
}

func TestParseReaderMissingStartUsesEndValue(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"end":2,"speaker":"A","text":"t"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if len(parsed.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(parsed.Segments))
	}
	if parsed.Segments[0].Start != 2 || parsed.Segments[0].End != 2 {
		t.Fatalf("segment timing = %v..%v, want 2..2", parsed.Segments[0].Start, parsed.Segments[0].End)
	}
}

func TestParseReaderMissingEndUsesStartValue(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"start":1,"speaker":"A","text":"t"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if len(parsed.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(parsed.Segments))
	}
	if parsed.Segments[0].Start != 1 || parsed.Segments[0].End != 1 {
		t.Fatalf("segment timing = %v..%v, want 1..1", parsed.Segments[0].Start, parsed.Segments[0].End)
	}
}

func TestParseReaderMissingSpeakerUsesUnknownPlaceholder(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"start":1,"end":2,"text":"t"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Segments[0].Speaker != "Unknown_Speaker" {
		t.Fatalf("speaker = %q, want Unknown_Speaker", parsed.Segments[0].Speaker)
	}
}

func TestParseReaderEmptySpeakerUsesUnknownPlaceholder(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"start":1,"end":2,"speaker":"   ","text":"t"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Segments[0].Speaker != "Unknown_Speaker" {
		t.Fatalf("speaker = %q, want Unknown_Speaker", parsed.Segments[0].Speaker)
	}
}

func TestParseReaderMissingTextDropsSegment(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"start":1,"end":2,"speaker":"A"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if len(parsed.Segments) != 0 {
		t.Fatalf("segment count = %d, want 0", len(parsed.Segments))
	}
}

func TestParseReaderEndBeforeStartSwapsValues(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"start":3,"end":2,"speaker":"A","text":"t"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Segments[0].Start != 2 || parsed.Segments[0].End != 3 {
		t.Fatalf("segment timing = %v..%v, want 2..3", parsed.Segments[0].Start, parsed.Segments[0].End)
	}
}

func TestParseReaderNegativeStartFails(t *testing.T) {
	_, err := ParseReader(strings.NewReader(`[{"start":-1,"end":2,"speaker":"A","text":"t"}]`))
	assertContains(t, err, "start must be >= 0")
}

func TestParseReaderEmptySegmentsArrayAccepted(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`{"segments":[]}`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if len(parsed.Segments) != 0 {
		t.Fatalf("segment count = %d, want 0", len(parsed.Segments))
	}
}

func TestParseReaderCategoriesPreservedWhenValid(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"start":1,"end":2,"speaker":"A","text":"t","categories":["filler","backchannel"]}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if len(parsed.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(parsed.Segments))
	}
	if len(parsed.Segments[0].Categories) != 2 {
		t.Fatalf("categories length = %d, want 2", len(parsed.Segments[0].Categories))
	}
	if parsed.Segments[0].Categories[0] != "filler" || parsed.Segments[0].Categories[1] != "backchannel" {
		t.Fatalf("categories = %v", parsed.Segments[0].Categories)
	}
}

func TestParseReaderMissingBothTimesMiddleUsesNeighborMidpoint(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[
		{"start":1,"end":2,"speaker":"A","text":"left"},
		{"speaker":"B","text":"middle"},
		{"start":6,"end":7,"speaker":"C","text":"right"}
	]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Segments[1].Start != 4 || parsed.Segments[1].End != 4 {
		t.Fatalf("middle timing = %v..%v, want 4..4", parsed.Segments[1].Start, parsed.Segments[1].End)
	}
}

func TestParseReaderMissingBothTimesEdgeFallbacks(t *testing.T) {
	parsedFirst, err := ParseReader(strings.NewReader(`[
		{"speaker":"A","text":"first"},
		{"start":5,"end":6,"speaker":"B","text":"second"}
	]`))
	if err != nil {
		t.Fatalf("parse first failed: %v", err)
	}
	if parsedFirst.Segments[0].Start != 5 || parsedFirst.Segments[0].End != 5 {
		t.Fatalf("first timing = %v..%v, want 5..5", parsedFirst.Segments[0].Start, parsedFirst.Segments[0].End)
	}

	parsedLast, err := ParseReader(strings.NewReader(`[
		{"start":1,"end":2,"speaker":"A","text":"first"},
		{"speaker":"B","text":"last"}
	]`))
	if err != nil {
		t.Fatalf("parse last failed: %v", err)
	}
	if parsedLast.Segments[1].Start != 2 || parsedLast.Segments[1].End != 2 {
		t.Fatalf("last timing = %v..%v, want 2..2", parsedLast.Segments[1].Start, parsedLast.Segments[1].End)
	}
}

func TestParseReaderMissingBothTimesSingleSegmentUsesZero(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[{"speaker":"A","text":"only"}]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if parsed.Segments[0].Start != 0 || parsed.Segments[0].End != 0 {
		t.Fatalf("timing = %v..%v, want 0..0", parsed.Segments[0].Start, parsed.Segments[0].End)
	}
}

func TestParseReaderEmptyOrWhitespaceTextDropped(t *testing.T) {
	parsed, err := ParseReader(strings.NewReader(`[
		{"start":1,"end":2,"speaker":"A","text":"ok"},
		{"start":2,"end":3,"speaker":"A","text":""},
		{"start":3,"end":4,"speaker":"A","text":"   "}
	]`))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	if len(parsed.Segments) != 1 {
		t.Fatalf("segment count = %d, want 1", len(parsed.Segments))
	}
}

func TestParseReaderOriginalInputIndexPreserved(t *testing.T) {
	input := `[
		{"start":1,"end":2,"speaker":"A","text":"one"},
		{"start":2,"end":3,"speaker":"B","text":"two"},
		{"start":3,"end":4,"speaker":"C","text":"three"}
	]`
	parsed, err := ParseReader(strings.NewReader(input))
	if err != nil {
		t.Fatalf("parse failed: %v", err)
	}
	for index, segment := range parsed.Segments {
		if segment.InputIndex != index {
			t.Fatalf("segment %d input index = %d, want %d", index, segment.InputIndex, index)
		}
	}
}

func assertContains(t *testing.T, err error, fragment string) {
	t.Helper()
	if err == nil {
		t.Fatalf("expected error containing %q", fragment)
	}
	if !strings.Contains(err.Error(), fragment) {
		t.Fatalf("error = %q, want substring %q", err.Error(), fragment)
	}
}