// Copyright 2016 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 query

import (
	"reflect"
	"regexp/syntax"
	"strings"
	"testing"
)

var opnames = map[syntax.Op]string{
	syntax.OpNoMatch:        "OpNoMatch",
	syntax.OpEmptyMatch:     "OpEmptyMatch",
	syntax.OpLiteral:        "OpLiteral",
	syntax.OpCharClass:      "OpCharClass",
	syntax.OpAnyCharNotNL:   "OpAnyCharNotNL",
	syntax.OpAnyChar:        "OpAnyChar",
	syntax.OpBeginLine:      "OpBeginLine",
	syntax.OpEndLine:        "OpEndLine",
	syntax.OpBeginText:      "OpBeginText",
	syntax.OpEndText:        "OpEndText",
	syntax.OpWordBoundary:   "OpWordBoundary",
	syntax.OpNoWordBoundary: "OpNoWordBoundary",
	syntax.OpCapture:        "OpCapture",
	syntax.OpStar:           "OpStar",
	syntax.OpPlus:           "OpPlus",
	syntax.OpQuest:          "OpQuest",
	syntax.OpRepeat:         "OpRepeat",
	syntax.OpConcat:         "OpConcat",
	syntax.OpAlternate:      "OpAlternate",
}

func printRegexp(t *testing.T, r *syntax.Regexp, lvl int) {
	t.Logf("%s%s ch: %d", strings.Repeat(" ", lvl), opnames[r.Op], len(r.Sub))
	for _, s := range r.Sub {
		printRegexp(t, s, lvl+1)
	}
}

func TestRegexpParse(t *testing.T) {
	type testcase struct {
		in           string
		query        Q
		isEquivalent bool
	}

	cases := []testcase{
		{"(foo|)bar", &Substring{Pattern: "bar"}, false},
		{"(foo|)", &Const{true}, false},
		{"(foo|bar)baz.*bla", &And{[]Q{
			&Or{[]Q{
				&Substring{Pattern: "foo"},
				&Substring{Pattern: "bar"},
			}},
			&Substring{Pattern: "baz"},
			&Substring{Pattern: "bla"},
		}}, false},
		{"^[a-z](People)+barrabas$",
			&And{[]Q{
				&Substring{Pattern: "People"},
				&Substring{Pattern: "barrabas"},
			}}, false},
		{"foo", &Substring{Pattern: "foo"}, true},
		{"^foo", &Substring{Pattern: "foo"}, false},
		{"(foo) (bar)", &And{[]Q{&Substring{Pattern: "foo"}, &Substring{Pattern: "bar"}}}, false},
		{"(thread|needle|haystack)", &Or{[]Q{
			&Substring{Pattern: "thread"},
			&Substring{Pattern: "needle"},
			&Substring{Pattern: "haystack"},
		}}, true},
	}

	for _, c := range cases {
		r, err := syntax.Parse(c.in, syntax.Perl)
		if err != nil {
			t.Errorf("Parse(%q): %v", c.in, err)
			continue
		}

		query, isEq := RegexpToQuery(r, 3)
		if !reflect.DeepEqual(c.query, query) {
			printRegexp(t, r, 0)
			t.Errorf("regexpToQuery(%q): got %v, want %v", c.in, query, c.query)
		}
		if isEq != c.isEquivalent {
			printRegexp(t, r, 0)
			t.Errorf("regexpToQuery(%q): got %v, want %v", c.in, isEq, c.isEquivalent)
		}
	}
}

func TestLowerRegexp(t *testing.T) {
	in := "[a-zA-Z]fooBAR"
	re := mustParseRE(in)
	in = re.String()
	got := LowerRegexp(re)
	want := "[a-za-z]foobar"
	if got.String() != want {
		printRegexp(t, re, 0)
		printRegexp(t, got, 0)
		t.Errorf("got %s, want %s", got, want)
	}

	if re.String() != in {
		t.Errorf("got mutated original %s want %s", re.String(), in)
	}
}