package gelf

import (
	"bytes"
	"log"
	"os"
	"os/exec"
	"testing"

	. "github.com/smartystreets/goconvey/convey"
	golf "gopkg.in/aphistic/golf.v0"
)

func TestSetDefaultConfig(t *testing.T) {
	Convey("SetDefaultConfig with empty host keeps GELF client disabled", t, func() {
		originalClient := c
		defer func() { c = originalClient }()

		c = nil
		SetDefaultConfig("", 12201, map[string]interface{}{"service": "test"})

		So(c, ShouldBeNil)
	})

	Convey("SetDefaultConfig with host initializes GELF client", t, func() {
		originalClient := c
		defer func() {
			if c != nil {
				c.Close()
			}
			c = originalClient
		}()

		c = nil
		SetDefaultConfig("127.0.0.1", 12201, map[string]interface{}{"service": "test"})

		So(c, ShouldNotBeNil)
	})
}

func TestLoggingWithoutGelfClient(t *testing.T) {
	Convey("Logging functions write to standard logger when GELF client is nil", t, func() {
		originalClient := c
		defer func() { c = originalClient }()
		c = nil

		buffer, restore := captureStandardLogger()
		defer restore()

		Debug("debug message")
		Debugf("debugf %d", 42)
		Info("info message")
		Infof("infof %s", "ok")
		Alert("alert message")
		Alertf("alertf %d", 7)

		output := buffer.String()
		So(output, ShouldContainSubstring, "debug message")
		So(output, ShouldContainSubstring, "debugf 42")
		So(output, ShouldContainSubstring, "info message")
		So(output, ShouldContainSubstring, "infof ok")
		So(output, ShouldContainSubstring, "Alert: alert message")
		So(output, ShouldContainSubstring, "Alert: alertf 7")
	})
}

func TestLoggingWithGelfClient(t *testing.T) {
	Convey("Logging functions execute without panic when GELF client is configured", t, func() {
		originalClient := c
		defer func() {
			if c != nil {
				c.Close()
			}
			c = originalClient
		}()

		client, err := golf.NewClient()
		So(err, ShouldBeNil)
		c = client
		So(c.Dial("udp://127.0.0.1:12201"), ShouldBeNil)

		logger, err := c.NewLogger()
		So(err, ShouldBeNil)
		golf.DefaultLogger(logger)

		buffer, restore := captureStandardLogger()
		defer restore()

		So(func() { Debug("debug with gelf") }, ShouldNotPanic)
		So(func() { Debugf("debugf %d", 1) }, ShouldNotPanic)
		So(func() { Info("info with gelf") }, ShouldNotPanic)
		So(func() { Infof("infof %d", 2) }, ShouldNotPanic)
		So(func() { Alert("alert with gelf") }, ShouldNotPanic)
		So(func() { Alertf("alertf %d", 3) }, ShouldNotPanic)

		output := buffer.String()
		So(output, ShouldContainSubstring, "debug with gelf")
		So(output, ShouldContainSubstring, "Alert: alert with gelf")
	})
}

func TestFatalExits(t *testing.T) {
	Convey("Fatal exits with non-zero status and logs message", t, func() {
		cmd := exec.Command(os.Args[0], "-test.run=TestFatalHelperProcess")
		cmd.Env = append(os.Environ(), "GO_WANT_FATAL_HELPER=1", "FATAL_MODE=plain", "FATAL_WITH_GELF=1")

		output, err := cmd.CombinedOutput()
		So(err, ShouldNotBeNil)
		So(string(output), ShouldContainSubstring, "Fatal: fatal message")
	})
}

func TestFatalfExits(t *testing.T) {
	Convey("Fatalf exits with non-zero status and logs formatted message", t, func() {
		cmd := exec.Command(os.Args[0], "-test.run=TestFatalHelperProcess")
		cmd.Env = append(os.Environ(), "GO_WANT_FATAL_HELPER=1", "FATAL_MODE=format", "FATAL_WITH_GELF=1")

		output, err := cmd.CombinedOutput()
		So(err, ShouldNotBeNil)
		So(string(output), ShouldContainSubstring, "Fatal: formatted 9")
	})
}

func TestFatalHelperProcess(t *testing.T) {
	if os.Getenv("GO_WANT_FATAL_HELPER") != "1" {
		return
	}

	log.SetFlags(0)
	mode := os.Getenv("FATAL_MODE")

	if os.Getenv("FATAL_WITH_GELF") == "1" {
		SetDefaultConfig("127.0.0.1", 12201, map[string]interface{}{"service": "test"})
	}

	if mode == "format" {
		Fatalf("formatted %d", 9)
	}

	Fatal("fatal message")
}

func captureStandardLogger() (*bytes.Buffer, func()) {
	var buffer bytes.Buffer
	originalWriter := log.Writer()
	originalFlags := log.Flags()
	originalPrefix := log.Prefix()

	log.SetOutput(&buffer)
	log.SetFlags(0)
	log.SetPrefix("")

	return &buffer, func() {
		log.SetOutput(originalWriter)
		log.SetFlags(originalFlags)
		log.SetPrefix(originalPrefix)
	}
}