package cli

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"

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

func TestMergeWritesPlaceholderOutputAndReport(t *testing.T) {
	dir := t.TempDir()
	inputA := writeFile(t, dir, "a.json")
	inputB := writeFile(t, dir, "b.json")
	speakers := writeFile(t, dir, "speakers.yml")
	output := filepath.Join(dir, "merged.json")
	reportPath := filepath.Join(dir, "report.json")

	err := executeMerge(
		"--input-file", inputB,
		"--input-file", inputA,
		"--speakers", speakers,
		"--output-file", output,
		"--report-file", reportPath,
	)
	if err != nil {
		t.Fatalf("merge failed: %v", err)
	}

	var transcript model.FinalTranscript
	readJSON(t, output, &transcript)
	outputBytes, err := os.ReadFile(output)
	if err != nil {
		t.Fatalf("read output bytes: %v", err)
	}
	outputJSON := string(outputBytes)
	if !strings.Contains(outputJSON, `"segments": []`) {
		t.Fatalf("expected segments to serialize as an empty array, got:\n%s", outputJSON)
	}
	if !strings.Contains(outputJSON, `"overlap_groups": []`) {
		t.Fatalf("expected overlap_groups to serialize as an empty array, got:\n%s", outputJSON)
	}
	if transcript.Metadata.Application != "seriatim" {
		t.Fatalf("unexpected application metadata: %q", transcript.Metadata.Application)
	}
	if got, want := transcript.Metadata.InputFiles, []string{inputA, inputB}; !equalStrings(got, want) {
		t.Fatalf("input files not sorted deterministically: got %v want %v", got, want)
	}
	if len(transcript.Segments) != 0 {
		t.Fatalf("expected placeholder output to contain no segments, got %d", len(transcript.Segments))
	}
	if len(transcript.OverlapGroups) != 0 {
		t.Fatalf("expected placeholder output to contain no overlap groups, got %d", len(transcript.OverlapGroups))
	}

	var rpt report.Report
	readJSON(t, reportPath, &rpt)
	gotModules := make([]string, 0, len(rpt.Events))
	for _, event := range rpt.Events {
		gotModules = append(gotModules, event.Module)
	}
	wantModules := []string{
		"json-files",
		"validate-raw",
		"normalize-speakers",
		"trim-text",
		"placeholder-merger",
		"detect-overlaps",
		"resolve-overlaps",
		"assign-ids",
		"validate-output",
		"json",
	}
	if !equalStrings(gotModules, wantModules) {
		t.Fatalf("report event order mismatch:\ngot  %v\nwant %v", gotModules, wantModules)
	}
}

func TestUnknownModulesFailDuringValidation(t *testing.T) {
	dir := t.TempDir()
	input := writeFile(t, dir, "input.json")
	speakers := writeFile(t, dir, "speakers.yml")
	output := filepath.Join(dir, "merged.json")

	tests := []struct {
		name string
		args []string
		want string
	}{
		{
			name: "input reader",
			args: []string{"--input-reader", "missing-reader"},
			want: `unknown input reader "missing-reader"`,
		},
		{
			name: "preprocessing",
			args: []string{"--preprocessing-modules", "validate-raw,missing-module"},
			want: `unknown preprocessing module "missing-module"`,
		},
		{
			name: "postprocessing",
			args: []string{"--postprocessing-modules", "missing-module"},
			want: `unknown postprocessing module "missing-module"`,
		},
		{
			name: "output",
			args: []string{"--output-modules", "missing-module"},
			want: `unknown output module "missing-module"`,
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			args := []string{
				"--input-file", input,
				"--speakers", speakers,
				"--output-file", output,
			}
			args = append(args, test.args...)

			err := executeMerge(args...)
			if err == nil {
				t.Fatal("expected error")
			}
			if !strings.Contains(err.Error(), test.want) {
				t.Fatalf("expected error to contain %q, got %q", test.want, err.Error())
			}
		})
	}
}

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

	err := executeMerge(
		"--input-file", input,
		"--output-file", output,
		"--preprocessing-modules", "trim-text,validate-raw",
	)
	if err == nil {
		t.Fatal("expected error")
	}
	if !strings.Contains(err.Error(), `requires state "canonical"`) {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestMissingInputFileFailsBeforePipelineExecution(t *testing.T) {
	dir := t.TempDir()
	speakers := writeFile(t, dir, "speakers.yml")
	output := filepath.Join(dir, "merged.json")

	err := executeMerge(
		"--input-file", filepath.Join(dir, "missing.json"),
		"--speakers", speakers,
		"--output-file", output,
	)
	if err == nil {
		t.Fatal("expected error")
	}
	if !strings.Contains(err.Error(), "--input-file") {
		t.Fatalf("unexpected error: %v", err)
	}
}

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

	err := executeMerge(
		"--input-file", input,
		"--output-file", output,
	)
	if err == nil {
		t.Fatal("expected error")
	}
	if !strings.Contains(err.Error(), "--speakers is required") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestAutocorrectRequiresAutocorrectFile(t *testing.T) {
	dir := t.TempDir()
	input := writeFile(t, dir, "input.json")
	speakers := writeFile(t, dir, "speakers.yml")
	output := filepath.Join(dir, "merged.json")

	err := executeMerge(
		"--input-file", input,
		"--speakers", speakers,
		"--output-file", output,
		"--preprocessing-modules", "validate-raw,normalize-speakers,autocorrect",
	)
	if err == nil {
		t.Fatal("expected error")
	}
	if !strings.Contains(err.Error(), "--autocorrect is required") {
		t.Fatalf("unexpected error: %v", err)
	}
}

func TestOutputJSONIsByteStable(t *testing.T) {
	dir := t.TempDir()
	inputA := writeFile(t, dir, "a.json")
	inputB := writeFile(t, dir, "b.json")
	speakers := writeFile(t, dir, "speakers.yml")
	outputA := filepath.Join(dir, "merged-a.json")
	outputB := filepath.Join(dir, "merged-b.json")

	args := []string{
		"--input-file", inputB,
		"--input-file", inputA,
		"--speakers", speakers,
	}

	err := executeMerge(append(append([]string(nil), args...), "--output-file", outputA)...)
	if err != nil {
		t.Fatalf("first merge failed: %v", err)
	}
	err = executeMerge(append(append([]string(nil), args...), "--output-file", outputB)...)
	if err != nil {
		t.Fatalf("second merge failed: %v", err)
	}

	first, err := os.ReadFile(outputA)
	if err != nil {
		t.Fatalf("read first output: %v", err)
	}
	second, err := os.ReadFile(outputB)
	if err != nil {
		t.Fatalf("read second output: %v", err)
	}
	if string(first) != string(second) {
		t.Fatalf("expected byte-stable output\nfirst:\n%s\nsecond:\n%s", first, second)
	}
}

func executeMerge(args ...string) error {
	cmd := NewRootCommand()
	cmd.SetArgs(append([]string{"merge"}, args...))
	return cmd.Execute()
}

func writeFile(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 file: %v", err)
	}
	return path
}

func readJSON(t *testing.T, path string, target any) {
	t.Helper()

	data, err := os.ReadFile(path)
	if err != nil {
		t.Fatalf("read %s: %v", path, err)
	}
	if err := json.Unmarshal(data, target); err != nil {
		t.Fatalf("unmarshal %s: %v", path, err)
	}
}

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
}