package config

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestOmittingNormalizeSpeakersDoesNotRequireSpeakers(t *testing.T) {
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	_, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  "validate-raw",
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("expected speakers file to be optional when normalize-speakers is omitted, got %v", err)
	}
}

func TestDuplicateInputFilesFailValidation(t *testing.T) {
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	_, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input, input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err == nil {
		t.Fatal("expected duplicate input error")
	}
	if !strings.Contains(err.Error(), "duplicate --input-file") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestOverlapWordRunGapDefaultsTo075(t *testing.T) {
	t.Setenv(OverlapWordRunGapEnv, "")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.OverlapWordRunGap != DefaultOverlapWordRunGap {
		t.Fatalf("gap = %f, want %f", cfg.OverlapWordRunGap, DefaultOverlapWordRunGap)
	}
}

func TestOverlapWordRunGapUsesValidEnvOverride(t *testing.T) {
	t.Setenv(OverlapWordRunGapEnv, "1.25")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.OverlapWordRunGap != 1.25 {
		t.Fatalf("gap = %f, want 1.25", cfg.OverlapWordRunGap)
	}
}

func TestOverlapWordRunGapRejectsInvalidEnvOverride(t *testing.T) {
	tests := []struct {
		name  string
		value string
		want  string
	}{
		{name: "non-numeric", value: "fast", want: "must be a positive number"},
		{name: "zero", value: "0", want: "must be positive"},
		{name: "negative", value: "-0.1", want: "must be positive"},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			t.Setenv(OverlapWordRunGapEnv, test.value)
			dir := t.TempDir()
			input := writeTempFile(t, dir, "input.json")
			output := filepath.Join(dir, "merged.json")

			_, err := NewMergeConfig(MergeOptions{
				InputFiles:            []string{input},
				OutputFile:            output,
				InputReader:           DefaultInputReader,
				OutputModules:         DefaultOutputModules,
				PreprocessingModules:  DefaultPreprocessingModules,
				PostprocessingModules: DefaultPostprocessingModules,
			})
			if err == nil {
				t.Fatal("expected error")
			}
			if !strings.Contains(err.Error(), test.want) {
				t.Fatalf("expected error to contain %q, got %v", test.want, err)
			}
		})
	}
}

func TestWordRunReorderWindowDefaultsTo04(t *testing.T) {
	t.Setenv(WordRunReorderWindowEnv, "")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.WordRunReorderWindow != DefaultWordRunReorderWindow {
		t.Fatalf("window = %f, want %f", cfg.WordRunReorderWindow, DefaultWordRunReorderWindow)
	}
}

func TestWordRunReorderWindowUsesValidEnvOverride(t *testing.T) {
	t.Setenv(WordRunReorderWindowEnv, "0.2")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.WordRunReorderWindow != 0.2 {
		t.Fatalf("window = %f, want 0.2", cfg.WordRunReorderWindow)
	}
}

func TestWordRunReorderWindowRejectsInvalidEnvOverride(t *testing.T) {
	tests := []struct {
		name  string
		value string
		want  string
	}{
		{name: "non-numeric", value: "fast", want: "must be a positive number"},
		{name: "zero", value: "0", want: "must be positive"},
		{name: "negative", value: "-0.1", want: "must be positive"},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			t.Setenv(WordRunReorderWindowEnv, test.value)
			dir := t.TempDir()
			input := writeTempFile(t, dir, "input.json")
			output := filepath.Join(dir, "merged.json")

			_, err := NewMergeConfig(MergeOptions{
				InputFiles:            []string{input},
				OutputFile:            output,
				InputReader:           DefaultInputReader,
				OutputModules:         DefaultOutputModules,
				PreprocessingModules:  DefaultPreprocessingModules,
				PostprocessingModules: DefaultPostprocessingModules,
			})
			if err == nil {
				t.Fatal("expected error")
			}
			if !strings.Contains(err.Error(), test.want) {
				t.Fatalf("expected error to contain %q, got %v", test.want, err)
			}
		})
	}
}

func TestBackchannelMaxDurationDefaultsTo2(t *testing.T) {
	t.Setenv(BackchannelMaxDurationEnv, "")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.BackchannelMaxDuration != DefaultBackchannelMaxDuration {
		t.Fatalf("backchannel max duration = %f, want %f", cfg.BackchannelMaxDuration, DefaultBackchannelMaxDuration)
	}
}

func TestBackchannelMaxDurationUsesValidEnvOverride(t *testing.T) {
	t.Setenv(BackchannelMaxDurationEnv, "1.5")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.BackchannelMaxDuration != 1.5 {
		t.Fatalf("backchannel max duration = %f, want 1.5", cfg.BackchannelMaxDuration)
	}
}

func TestBackchannelMaxDurationRejectsInvalidEnvOverride(t *testing.T) {
	assertPositiveFloatEnvValidation(t, BackchannelMaxDurationEnv)
}

func TestFillerMaxDurationDefaultsTo125(t *testing.T) {
	t.Setenv(FillerMaxDurationEnv, "")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.FillerMaxDuration != DefaultFillerMaxDuration {
		t.Fatalf("filler max duration = %f, want %f", cfg.FillerMaxDuration, DefaultFillerMaxDuration)
	}
}

func TestFillerMaxDurationUsesValidEnvOverride(t *testing.T) {
	t.Setenv(FillerMaxDurationEnv, "1.75")
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.FillerMaxDuration != 1.75 {
		t.Fatalf("filler max duration = %f, want 1.75", cfg.FillerMaxDuration)
	}
}

func TestFillerMaxDurationRejectsInvalidEnvOverride(t *testing.T) {
	assertPositiveFloatEnvValidation(t, FillerMaxDurationEnv)
}

func TestCoalesceGapDefaultsTo3(t *testing.T) {
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.CoalesceGap != DefaultCoalesceGap {
		t.Fatalf("coalesce gap = %f, want %f", cfg.CoalesceGap, DefaultCoalesceGap)
	}
}

func TestCoalesceGapUsesValidOverride(t *testing.T) {
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
		CoalesceGap:           "1.5",
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.CoalesceGap != 1.5 {
		t.Fatalf("coalesce gap = %f, want 1.5", cfg.CoalesceGap)
	}
}

func TestCoalesceGapAllowsZero(t *testing.T) {
	dir := t.TempDir()
	input := writeTempFile(t, dir, "input.json")
	output := filepath.Join(dir, "merged.json")

	cfg, err := NewMergeConfig(MergeOptions{
		InputFiles:            []string{input},
		OutputFile:            output,
		InputReader:           DefaultInputReader,
		OutputModules:         DefaultOutputModules,
		PreprocessingModules:  DefaultPreprocessingModules,
		PostprocessingModules: DefaultPostprocessingModules,
		CoalesceGap:           "0",
	})
	if err != nil {
		t.Fatalf("config failed: %v", err)
	}
	if cfg.CoalesceGap != 0 {
		t.Fatalf("coalesce gap = %f, want 0", cfg.CoalesceGap)
	}
}

func TestCoalesceGapRejectsInvalidOverride(t *testing.T) {
	tests := []struct {
		name  string
		value string
		want  string
	}{
		{name: "non-numeric", value: "fast", want: "must be a non-negative number"},
		{name: "negative", value: "-0.1", want: "must be non-negative"},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			dir := t.TempDir()
			input := writeTempFile(t, dir, "input.json")
			output := filepath.Join(dir, "merged.json")

			_, err := NewMergeConfig(MergeOptions{
				InputFiles:            []string{input},
				OutputFile:            output,
				InputReader:           DefaultInputReader,
				OutputModules:         DefaultOutputModules,
				PreprocessingModules:  DefaultPreprocessingModules,
				PostprocessingModules: DefaultPostprocessingModules,
				CoalesceGap:           test.value,
			})
			if err == nil {
				t.Fatal("expected error")
			}
			if !strings.Contains(err.Error(), test.want) {
				t.Fatalf("expected error to contain %q, got %v", test.want, err)
			}
		})
	}
}

func assertPositiveFloatEnvValidation(t *testing.T, envName string) {
	t.Helper()

	tests := []struct {
		name  string
		value string
		want  string
	}{
		{name: "non-numeric", value: "fast", want: "must be a positive number"},
		{name: "zero", value: "0", want: "must be positive"},
		{name: "negative", value: "-0.1", want: "must be positive"},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			t.Setenv(envName, test.value)
			dir := t.TempDir()
			input := writeTempFile(t, dir, "input.json")
			output := filepath.Join(dir, "merged.json")

			_, err := NewMergeConfig(MergeOptions{
				InputFiles:            []string{input},
				OutputFile:            output,
				InputReader:           DefaultInputReader,
				OutputModules:         DefaultOutputModules,
				PreprocessingModules:  DefaultPreprocessingModules,
				PostprocessingModules: DefaultPostprocessingModules,
			})
			if err == nil {
				t.Fatal("expected error")
			}
			if !strings.Contains(err.Error(), test.want) {
				t.Fatalf("expected error to contain %q, got %v", test.want, err)
			}
		})
	}
}

func writeTempFile(t *testing.T, dir string, name string) string {
	t.Helper()

	path := filepath.Join(dir, name)
	if err := os.WriteFile(path, []byte("{}\n"), 0o600); err != nil {
		t.Fatalf("write temp file: %v", err)
	}
	return path
}