package logging

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

func TestNew_TextFormat(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "text.log")
	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("unexpected error opening file: %v", err)
	}
	defer func() { _ = file.Close() }()

	logger := New(InfoLevel, file)
	logger.Info("hello world")

	data, err := os.ReadFile(path) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read log file: %v", err)
	}
	out := string(data)

	if !strings.Contains(out, "hello world") {
		t.Fatalf("expected output to contain message, got: %q", out)
	}
	if !strings.Contains(out, "level=INFO") {
		t.Fatalf("expected text output to contain level=INFO, got: %q", out)
	}
	if json.Valid(data) {
		t.Fatalf("expected non-JSON text output, got JSON: %q", out)
	}
}

func TestNewFromConfig_JSONOutput(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "json.log")

	logger, err := NewFromConfig("info", path)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	logger.Info("structured message")

	data, err := os.ReadFile(path) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read log file: %v", err)
	}

	var payload map[string]interface{}
	if err := json.Unmarshal(data, &payload); err != nil {
		t.Fatalf("expected valid JSON output, got error %v; output: %q", err, string(data))
	}

	if payload["msg"] != "structured message" {
		t.Fatalf("expected msg field to equal message, got: %v", payload["msg"])
	}
	if payload["level"] != "INFO" {
		t.Fatalf("expected level field INFO, got: %v", payload["level"])
	}
	timeVal, ok := payload["time"].(string)
	if !ok {
		t.Fatalf("expected time field to be a string, got: %v", payload["time"])
	}
	if _, err := time.Parse(time.RFC3339, timeVal); err != nil {
		t.Fatalf("expected time field to be RFC3339, got %q: %v", timeVal, err)
	}
}

func TestLevelFiltering_DebugSuppressedAtInfo(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "level.log")
	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("unexpected error opening file: %v", err)
	}
	defer func() { _ = file.Close() }()

	logger := New(InfoLevel, file)
	logger.Debug("should not appear")
	logger.Info("should appear")

	data, err := os.ReadFile(path) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read log file: %v", err)
	}
	out := string(data)

	if strings.Contains(out, "should not appear") {
		t.Fatalf("expected debug message to be suppressed, got: %q", out)
	}
	if !strings.Contains(out, "should appear") {
		t.Fatalf("expected info message to be present, got: %q", out)
	}
}

func TestNewFromOptions_FileOutput(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "out.log")

	logger, err := NewFromOptions("info", "json", path)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}

	logger.Info("file message")

	data, err := os.ReadFile(path) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read log file: %v", err)
	}

	var payload map[string]interface{}
	if err := json.Unmarshal(data, &payload); err != nil {
		t.Fatalf("expected valid JSON in file, got error %v; contents: %q", err, string(data))
	}
	if payload["msg"] != "file message" {
		t.Fatalf("expected msg field, got: %v", payload["msg"])
	}
}

func TestNewFromOptions_FormatSelection(t *testing.T) {
	dir := t.TempDir()

	jsonPath := filepath.Join(dir, "json.log")
	jsonLogger, err := NewFromOptions("info", "json", jsonPath)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	jsonLogger.Info("json message")

	jsonData, err := os.ReadFile(jsonPath) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read json log file: %v", err)
	}
	if !json.Valid(jsonData) {
		t.Fatalf("expected valid JSON, got: %q", string(jsonData))
	}

	textPath := filepath.Join(dir, "text.log")
	textLogger, err := NewFromOptions("info", "text", textPath)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	textLogger.Info("text message")

	textData, err := os.ReadFile(textPath) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read text log file: %v", err)
	}
	if json.Valid(textData) {
		t.Fatalf("expected non-JSON text output, got: %q", string(textData))
	}
	if !strings.Contains(string(textData), `msg="text message"`) {
		t.Fatalf("expected text output to contain msg attribute, got: %q", string(textData))
	}

	// Default format ("" -> json) via NewFromOptions.
	defaultPath := filepath.Join(dir, "default.log")
	defaultLogger, err := NewFromOptions("info", "", defaultPath)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	defaultLogger.Info("default message")

	defaultData, err := os.ReadFile(defaultPath) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read default log file: %v", err)
	}
	if !json.Valid(defaultData) {
		t.Fatalf("expected empty format to default to JSON, got: %q", string(defaultData))
	}

	// NewFromConfig should also default to JSON.
	configPath := filepath.Join(dir, "config.log")
	configLogger, err := NewFromConfig("info", configPath)
	if err != nil {
		t.Fatalf("unexpected error: %v", err)
	}
	configLogger.Info("config message")

	configData, err := os.ReadFile(configPath) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read config log file: %v", err)
	}
	if !json.Valid(configData) {
		t.Fatalf("expected NewFromConfig to default to JSON format, got: %q", string(configData))
	}
}

func TestSlogAccessor(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "slog.log")
	file, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("unexpected error opening file: %v", err)
	}
	defer func() { _ = file.Close() }()

	logger := New(InfoLevel, file)
	if logger.Slog() == nil {
		t.Fatal("expected Slog() to return a non-nil *slog.Logger")
	}

	logger.Slog().Info("via slog accessor")

	data, err := os.ReadFile(path) //nolint:gosec // path is from t.TempDir()
	if err != nil {
		t.Fatalf("failed to read log file: %v", err)
	}
	if !strings.Contains(string(data), "via slog accessor") {
		t.Fatalf("expected message logged via Slog() accessor, got: %q", string(data))
	}
}