package pflag

import (
	"bytes"
	"io"
	"strings"
	"testing"
)

const expectedOutput = `      --long-form[=true|false]    Some description
      --long-form2[=true|false]   Some description
                                    with multiline
  -s, --long-name[=true|false]    Some description
  -t, --long-name2[=true|false]   Some description with
                                    multiline
`

func setUpPFlagSet(buf io.Writer) *FlagSet {
	f := NewFlagSet("test", ExitOnError)
	f.Bool("long-form", false, "Some description")
	f.Bool("long-form2", false, "Some description\n  with multiline")
	f.BoolP("long-name", "s", false, "Some description")
	f.BoolP("long-name2", "t", false, "Some description with\n  multiline")
	f.SetOutput(buf)
	return f
}

func TestPrintUsage(t *testing.T) {
	buf := bytes.Buffer{}
	f := setUpPFlagSet(&buf)
	f.PrintDefaults()
	res := buf.String()
	if res != expectedOutput {
		t.Errorf("Expected \n%s \nActual \n%s", expectedOutput, res)
	}
}

func setUpPFlagSet2(buf io.Writer) *FlagSet {
	f := NewFlagSet("test", ExitOnError)
	f.Bool("long-form", false, "Some description")
	f.Bool("long-form2", false, "Some description\n  with multiline")
	f.BoolP("long-name", "s", false, "Some description")
	f.BoolP("long-name2", "t", false, "Some description with\n  multiline")
	f.StringP("some-very-long-arg", "l", "test", "Some very long description having break the limit")
	f.StringP("other-very-long-arg", "o", "long-default-value", "Some very long description having break the limit")
	f.String("some-very-long-arg2", "very long default value", "Some very long description\nwith line break\nmultiple")
	f.SetOutput(buf)
	return f
}

const expectedOutput2 = `      --long-form[=true|false]       Some description
      --long-form2[=true|false]      Some description
                                       with multiline
  -s, --long-name[=true|false]       Some description
  -t, --long-name2[=true|false]      Some description with
                                       multiline
  -o, --other-very-long-arg string   Some very long description having
                                     break the limit (default
                                     "long-default-value")
  -l, --some-very-long-arg string    Some very long description having
                                     break the limit (default "test")
      --some-very-long-arg2 string   Some very long description
                                     with line break
                                     multiple (default "very long default
                                     value")
`

func TestPrintUsage_2(t *testing.T) {
	buf := bytes.Buffer{}
	f := setUpPFlagSet2(&buf)
	res := f.FlagUsagesWrapped(80)
	if res != expectedOutput2 {
		t.Errorf("Expected \n%s \nActual \n%s", expectedOutput2, res)
	}
}

const expectedOutput3 = `      --mount string   a mount specification e.g.
                       'type=bind,source=/opt,destination=/hostopt'.
                       The rest of this description is
                       wrapped.
`

// A word wider than the description column has to overflow, but only that
// word: wrapping resumes on the next one.
func TestPrintUsage_WrapsAfterUnbreakableWord(t *testing.T) {
	f := NewFlagSet("test", ExitOnError)
	f.String("mount", "", "a mount specification e.g. 'type=bind,source=/opt,destination=/hostopt'. The rest of this description is wrapped.")

	res := f.FlagUsagesWrapped(60)
	if res != expectedOutput3 {
		t.Errorf("Expected \n%s \nActual \n%s", expectedOutput3, res)
	}
}

// No line may be longer than the requested width unless it is a single word
// that cannot be broken at all.
func TestPrintUsage_OnlyUnbreakableWordsOverflow(t *testing.T) {
	usages := []string{
		"a mount specification e.g. 'type=bind,source=/opt,destination=/hostopt'. The rest of this description is wrapped.",
		"https://example.com/a/very/long/url/that/will/not/fit/in/the/column and some words after it to wrap",
		"averyveryverylongwordrightatthestart followed by several shorter words",
		"short words then averyveryverylongwordinthemiddle and more words after that one",
		"trailing text ending in anextremelylongunbreakabletokenattheveryend",
	}

	for _, width := range []int{40, 60, 80} {
		for _, usage := range usages {
			f := NewFlagSet("test", ExitOnError)
			f.String("mount", "", usage)

			lines := strings.Split(strings.TrimRight(f.FlagUsagesWrapped(width), "\n"), "\n")
			if len(lines) < 2 {
				t.Errorf("width %d, usage %q: expected the description to wrap", width, usage)
				continue
			}

			// Continuation lines are padded to the description column, so
			// their indent says where the description starts on every line.
			indent := len(lines[1]) - len(strings.TrimLeft(lines[1], " "))

			for _, line := range lines {
				if len(line) <= width || indent >= len(line) {
					continue
				}
				if strings.Contains(strings.TrimSpace(line[indent:]), " ") {
					t.Errorf("width %d, usage %q: line is %d wide and still has a break point:\n%s",
						width, usage, len(line), line)
				}
			}
		}
	}
}