package main

import (
	"flag"
	"github.com/stretchr/testify/assert"
	"os"
	"strings"
	"testing"
)

func TestFlags(t *testing.T) {
	// We manipulate the Args to set them up for the testcases
	// after this test we restore the initial args
	oldArgs := os.Args
	defer func() { os.Args = oldArgs }()

	cases := []struct {
		Name           string
		Args           []string
		ExpectedExit   int
		ExpectedOutput string
	}{
		{"No flags",
			[]string{"testdata/first"},
			0,
			"alabama barcelona\nbarcelona california\ncalifornia denver\ncalifornia denver\nамур брянск\nбелгород волгоград\nволгоград геленджик",
		},
		{"Reverse",
			[]string{"-r", "testdata/first"},
			0,
			"волгоград геленджик\nбелгород волгоград\nамур брянск\ncalifornia denver\ncalifornia denver\nbarcelona california\nalabama barcelona",
		},
		{"Unique",
			[]string{"-u", "testdata/first"},
			0,
			"alabama barcelona\nbarcelona california\ncalifornia denver\nамур брянск\nбелгород волгоград\nволгоград геленджик",
		},
		{"Column 2",
			[]string{"-k=2", "testdata/first"},
			0,
			"alabama barcelona\nbarcelona california\ncalifornia denver\ncalifornia denver\nамур брянск\nбелгород волгоград\nволгоград геленджик",
		},
	}

	for _, tc := range cases {
		tc := tc

		t.Run(tc.Name, func(t *testing.T) {
			// this call is required because otherwise flags panics, if args are set between flag.Parse calls
			flag.CommandLine = flag.NewFlagSet(tc.Name, flag.ExitOnError)
			// we need a value to set Args[0] to, cause flag begins parsing at Args[1]
			os.Args = append([]string{tc.Name}, tc.Args...)

			assert.Equal(t, tc.ExpectedOutput, strings.Trim(run(), "\n"))
		})
	}
}