package starlog

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"io"
	"os"
	"regexp"
	"strings"
	"testing"
)

var ansiRegex = regexp.MustCompile(`\x1b\[[0-9;]*m`)

func newStructuredTestLogger(output io.Writer) *StarLogger {
	logger := NewStarlog(output)
	logger.SetShowStd(false)
	logger.SetShowColor(false)
	logger.SetShowOriginFile(false)
	logger.SetShowFuncName(false)
	logger.SetShowFlag(false)
	return logger
}

func TestWithFieldAndWithFields(t *testing.T) {
	var buf bytes.Buffer
	logger := newStructuredTestLogger(&buf)

	logger.WithField("user_id", 42).WithFields(Fields{
		"module": "auth",
		"ip":     "127.0.0.1",
	}).Info("login ok")

	logStr := buf.String()
	if !strings.Contains(logStr, "login ok") {
		t.Fatalf("expected message in log, got %q", logStr)
	}
	if !strings.Contains(logStr, "user_id=42") || !strings.Contains(logStr, "module=auth") || !strings.Contains(logStr, "ip=127.0.0.1") {
		t.Fatalf("expected structured fields in log, got %q", logStr)
	}
}

func TestWithFieldIsolation(t *testing.T) {
	var buf bytes.Buffer
	logger := newStructuredTestLogger(&buf)

	logger.Info("base")
	baseLog := buf.String()
	if strings.Contains(baseLog, "req_id=") {
		t.Fatalf("base logger should not include req_id field, got %q", baseLog)
	}

	buf.Reset()
	logger.WithField("req_id", "r-1").Info("child")
	childLog := buf.String()
	if !strings.Contains(childLog, "req_id=r-1") {
		t.Fatalf("child logger should include req_id field, got %q", childLog)
	}

	buf.Reset()
	logger.Info("base-again")
	baseAgain := buf.String()
	if strings.Contains(baseAgain, "req_id=r-1") {
		t.Fatalf("base logger should remain clean after WithField, got %q", baseAgain)
	}
}

func TestWithError(t *testing.T) {
	var buf bytes.Buffer
	logger := newStructuredTestLogger(&buf)

	logger.WithError(errors.New("boom")).Error("request failed")
	logStr := buf.String()
	if !strings.Contains(logStr, "request failed") || !strings.Contains(logStr, "error=boom") {
		t.Fatalf("expected error details in log, got %q", logStr)
	}
}

func TestWithContextExtractor(t *testing.T) {
	var buf bytes.Buffer
	logger := newStructuredTestLogger(&buf)
	logger.SetContextFieldExtractor(func(ctx context.Context) Fields {
		traceID, _ := ctx.Value("trace_id").(string)
		if traceID == "" {
			return nil
		}
		return Fields{"trace_id": traceID}
	})

	ctx := context.WithValue(context.Background(), "trace_id", "trace-001")
	logger.WithContext(ctx).Info("context log")

	logStr := buf.String()
	if !strings.Contains(logStr, "context log") || !strings.Contains(logStr, "trace_id=trace-001") {
		t.Fatalf("expected context extracted fields in log, got %q", logStr)
	}
}

func TestJSONFormatterWithStructuredFields(t *testing.T) {
	var buf bytes.Buffer
	logger := newStructuredTestLogger(&buf)
	logger.SetFormatter(NewJSONFormatter())
	logger.SetShowColor(false)

	logger.WithField("user_id", 7).WithError(errors.New("db down")).Error("save failed")

	payload := make(map[string]interface{})
	if err := json.Unmarshal(buf.Bytes(), &payload); err != nil {
		t.Fatalf("json unmarshal failed: %v, raw=%q", err, buf.String())
	}
	if payload["msg"] != "save failed" {
		t.Fatalf("unexpected msg: %v", payload["msg"])
	}
	if payload["error"] != "db down" {
		t.Fatalf("unexpected error field: %v", payload["error"])
	}
	fieldsObj, ok := payload["fields"].(map[string]interface{})
	if !ok {
		t.Fatalf("fields should be object, got %T", payload["fields"])
	}
	if fieldsObj["user_id"] != float64(7) {
		t.Fatalf("unexpected user_id value: %v", fieldsObj["user_id"])
	}
}

func TestLevelOnlyFieldColorRender(t *testing.T) {
	oldNoColor := NoColor
	NoColor = false
	defer func() {
		NoColor = oldNoColor
	}()

	logger := NewStarlog(nil)
	logger.SetShowStd(true)
	logger.SetShowColor(true)
	logger.SetColorMode(ColorModeLevelOnly)
	logger.SetShowOriginFile(false)
	logger.SetShowFuncName(false)
	logger.SetShowFlag(false)
	logger.SetShowFieldColor(true)

	var out bytes.Buffer
	oldStd := stdScreen
	oldErr := errScreen
	stdScreen = &out
	errScreen = io.Discard
	defer func() {
		stdScreen = oldStd
		errScreen = oldErr
	}()

	logger.WithFields(Fields{
		"user": "alice",
		"ok":   true,
		"cnt":  3,
	}).Info("login")

	rendered := out.String()
	if !strings.Contains(rendered, "\x1b[") {
		t.Fatalf("expected ansi colors in rendered log, got %q", rendered)
	}
	clean := ansiRegex.ReplaceAllString(rendered, "")
	if !strings.Contains(clean, "user=alice") || !strings.Contains(clean, "ok=true") || !strings.Contains(clean, "cnt=3") {
		t.Fatalf("expected fields in rendered log, got %q", clean)
	}
}

func TestDisableFieldColorRender(t *testing.T) {
	oldNoColor := NoColor
	NoColor = false
	defer func() {
		NoColor = oldNoColor
	}()

	logger := NewStarlog(nil)
	logger.SetShowStd(true)
	logger.SetShowColor(true)
	logger.SetColorMode(ColorModeLevelOnly)
	logger.SetShowOriginFile(false)
	logger.SetShowFuncName(false)
	logger.SetShowFlag(false)
	logger.SetShowFieldColor(false)

	var out bytes.Buffer
	oldStd := stdScreen
	oldErr := errScreen
	stdScreen = &out
	errScreen = os.Stderr
	defer func() {
		stdScreen = oldStd
		errScreen = oldErr
	}()

	logger.WithField("user", "alice").Info("login")
	rendered := out.String()
	if strings.Count(rendered, "\x1b[") > 2 {
		t.Fatalf("field color should be disabled, got %q", rendered)
	}
}