package level_test

import (
	"bytes"
	"errors"
	"io"
	"strings"
	"testing"

	"github.com/go-kit/log"
	"github.com/go-kit/log/level"
)

func TestVariousLevels(t *testing.T) {
	testCases := []struct {
		name    string
		allowed level.Option
		want    string
	}{
		{
			"AllowAll",
			level.AllowAll(),
			strings.Join([]string{
				`{"level":"debug","this is":"debug log"}`,
				`{"level":"info","this is":"info log"}`,
				`{"level":"warn","this is":"warn log"}`,
				`{"level":"error","this is":"error log"}`,
			}, "\n"),
		},
		{
			"AllowDebug",
			level.AllowDebug(),
			strings.Join([]string{
				`{"level":"debug","this is":"debug log"}`,
				`{"level":"info","this is":"info log"}`,
				`{"level":"warn","this is":"warn log"}`,
				`{"level":"error","this is":"error log"}`,
			}, "\n"),
		},
		{
			"AllowInfo",
			level.AllowInfo(),
			strings.Join([]string{
				`{"level":"info","this is":"info log"}`,
				`{"level":"warn","this is":"warn log"}`,
				`{"level":"error","this is":"error log"}`,
			}, "\n"),
		},
		{
			"AllowWarn",
			level.AllowWarn(),
			strings.Join([]string{
				`{"level":"warn","this is":"warn log"}`,
				`{"level":"error","this is":"error log"}`,
			}, "\n"),
		},
		{
			"AllowError",
			level.AllowError(),
			strings.Join([]string{
				`{"level":"error","this is":"error log"}`,
			}, "\n"),
		},
		{
			"AllowNone",
			level.AllowNone(),
			``,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			var buf bytes.Buffer
			logger := level.NewFilter(log.NewJSONLogger(&buf), tc.allowed)

			level.Debug(logger).Log("this is", "debug log")
			level.Info(logger).Log("this is", "info log")
			level.Warn(logger).Log("this is", "warn log")
			level.Error(logger).Log("this is", "error log")

			if want, have := tc.want, strings.TrimSpace(buf.String()); want != have {
				t.Errorf("\nwant:\n%s\nhave:\n%s", want, have)
			}
		})
	}
}

func TestErrNotAllowed(t *testing.T) {
	myError := errors.New("squelched!")
	opts := []level.Option{
		level.AllowWarn(),
		level.ErrNotAllowed(myError),
	}
	logger := level.NewFilter(log.NewNopLogger(), opts...)

	if want, have := myError, level.Info(logger).Log("foo", "bar"); want != have {
		t.Errorf("want %#+v, have %#+v", want, have)
	}

	if want, have := error(nil), level.Warn(logger).Log("foo", "bar"); want != have {
		t.Errorf("want %#+v, have %#+v", want, have)
	}
}

func TestErrNoLevel(t *testing.T) {
	myError := errors.New("no level specified")

	var buf bytes.Buffer
	opts := []level.Option{
		level.SquelchNoLevel(true),
		level.ErrNoLevel(myError),
	}
	logger := level.NewFilter(log.NewJSONLogger(&buf), opts...)

	if want, have := myError, logger.Log("foo", "bar"); want != have {
		t.Errorf("want %v, have %v", want, have)
	}
	if want, have := ``, strings.TrimSpace(buf.String()); want != have {
		t.Errorf("\nwant '%s'\nhave '%s'", want, have)
	}
}

func TestAllowNoLevel(t *testing.T) {
	var buf bytes.Buffer
	opts := []level.Option{
		level.SquelchNoLevel(false),
		level.ErrNoLevel(errors.New("I should never be returned!")),
	}
	logger := level.NewFilter(log.NewJSONLogger(&buf), opts...)

	if want, have := error(nil), logger.Log("foo", "bar"); want != have {
		t.Errorf("want %v, have %v", want, have)
	}
	if want, have := `{"foo":"bar"}`, strings.TrimSpace(buf.String()); want != have {
		t.Errorf("\nwant '%s'\nhave '%s'", want, have)
	}
}

func TestLevelContext(t *testing.T) {
	var buf bytes.Buffer

	// Wrapping the level logger with a context allows users to use
	// log.DefaultCaller as per normal.
	var logger log.Logger
	logger = log.NewLogfmtLogger(&buf)
	logger = level.NewFilter(logger, level.AllowAll())
	logger = log.With(logger, "caller", log.DefaultCaller)

	level.Info(logger).Log("foo", "bar")
	if want, have := `level=info caller=level_test.go:149 foo=bar`, strings.TrimSpace(buf.String()); want != have {
		t.Errorf("\nwant '%s'\nhave '%s'", want, have)
	}
}

func TestContextLevel(t *testing.T) {
	var buf bytes.Buffer

	// Wrapping a context with the level logger still works, but requires users
	// to specify a higher callstack depth value.
	var logger log.Logger
	logger = log.NewLogfmtLogger(&buf)
	logger = log.With(logger, "caller", log.Caller(5))
	logger = level.NewFilter(logger, level.AllowAll())

	level.Info(logger).Log("foo", "bar")
	if want, have := `caller=level_test.go:165 level=info foo=bar`, strings.TrimSpace(buf.String()); want != have {
		t.Errorf("\nwant '%s'\nhave '%s'", want, have)
	}
}

func TestLevelFormatting(t *testing.T) {
	testCases := []struct {
		name   string
		format func(io.Writer) log.Logger
		output string
	}{
		{
			name:   "logfmt",
			format: log.NewLogfmtLogger,
			output: `level=info foo=bar`,
		},
		{
			name:   "JSON",
			format: log.NewJSONLogger,
			output: `{"foo":"bar","level":"info"}`,
		},
	}

	for _, tc := range testCases {
		t.Run(tc.name, func(t *testing.T) {
			var buf bytes.Buffer

			logger := tc.format(&buf)
			level.Info(logger).Log("foo", "bar")
			if want, have := tc.output, strings.TrimSpace(buf.String()); want != have {
				t.Errorf("\nwant: '%s'\nhave '%s'", want, have)
			}
		})
	}
}

func TestInjector(t *testing.T) {
	var (
		output []interface{}
		logger log.Logger
	)

	logger = log.LoggerFunc(func(keyvals ...interface{}) error {
		output = keyvals
		return nil
	})
	logger = level.NewInjector(logger, level.InfoValue())

	logger.Log("foo", "bar")
	if got, want := len(output), 4; got != want {
		t.Errorf("missing level not injected: got len==%d, want len==%d", got, want)
	}
	if got, want := output[0], level.Key(); got != want {
		t.Errorf("wrong level key: got %#v, want %#v", got, want)
	}
	if got, want := output[1], level.InfoValue(); got != want {
		t.Errorf("wrong level value: got %#v, want %#v", got, want)
	}

	level.Error(logger).Log("foo", "bar")
	if got, want := len(output), 4; got != want {
		t.Errorf("leveled record modified: got len==%d, want len==%d", got, want)
	}
	if got, want := output[0], level.Key(); got != want {
		t.Errorf("wrong level key: got %#v, want %#v", got, want)
	}
	if got, want := output[1], level.ErrorValue(); got != want {
		t.Errorf("wrong level value: got %#v, want %#v", got, want)
	}
}
