/*
 * Copyright 2014 Google Inc. All rights reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package natsort

import "testing"

func TestLess(t *testing.T) {
	tests := []struct {
		s, t string
		want cmp
	}{
		{"", "", eq},
		{"a", "", gt},
		{"a", "a", eq},
		{"1", "10", lt},
		{"20", "3", gt},
		{"a1", "a10", lt},
		{"a2", "a10", lt},
		{"a5b2", "a5b7", lt},
		{"a50b2", "a6b7", gt},
		{"世20", "世界3", lt},
		{"50a", "50b", lt},
		{"a50", "a050", gt},
		{"a01b3", "a1b2", lt},
		{"thx1138", "thx1138", eq},
		{"thx1138a", "thx1138b", lt},
		{"thx1138a", "thx1138", gt},

		// a < a0 < a1 < a1a < a1b < a2 < a10 < a20
		{"a", "a0", lt},
		{"a0", "a1", lt},
		{"a1", "a1a", lt},
		{"a1a", "a1b", lt},
		{"a2", "a10", lt},
		{"a10", "a20", lt},

		// 1.001 < 1.002 < 1.010 < 1.02 < 1.1 < 1.3
		{"1.001", "1.002", lt},
		{"1.002", "1.010", lt},
		{"1.010", "1.02", gt}, // TODO(light): should this be lt?
		{"1.02", "1.1", gt},   // TODO(light): should this be lt?
		{"1.1", "1.3", lt},
	}
	for _, test := range tests {
		v := bit(Less(test.s, test.t))
		v |= bit(Less(test.t, test.s)) << 1
		if cmp(v) != test.want {
			t.Errorf("%[1]q %[3]v %[2]q, want %[1]q %[4]v %[2]q", test.s, test.t, cmp(v), test.want)
		}
	}
}

func bit(b bool) int {
	if b {
		return 1
	} else {
		return 0
	}
}

type cmp int

const (
	eq cmp = iota
	lt
	gt
)

func (c cmp) String() string {
	switch c {
	case lt:
		return "<"
	case gt:
		return ">"
	case eq:
		return "=="
	default:
		return "<>"
	}
}