// Copyright 2020 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 zoekt

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

	"github.com/google/zoekt/query"
)

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 substrMT(pattern string) matchTree {
	d := &indexData{}
	mt, _ := d.newSubstringMatchTree(&query.Substring{
		Pattern: pattern,
	})
	return mt
}

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

	cases := []testcase{
		{"(foo|)bar", substrMT("bar"), false},
		{"(foo|)", &bruteForceMatchTree{}, false},
		{"(foo|bar)baz.*bla", &andMatchTree{[]matchTree{
			&orMatchTree{[]matchTree{
				substrMT("foo"),
				substrMT("bar"),
			}},
			substrMT("baz"),
			substrMT("bla"),
		}}, false},
		{
			"^[a-z](People)+barrabas$",
			&andMatchTree{[]matchTree{
				substrMT("People"),
				substrMT("barrabas"),
			}}, false,
		},
		{"foo", substrMT("foo"), true},
		{"^foo", substrMT("foo"), false},
		{"(foo) (bar)", &andMatchTree{[]matchTree{substrMT("foo"), substrMT("bar")}}, false},
		{"(thread|needle|haystack)", &orMatchTree{[]matchTree{
			substrMT("thread"),
			substrMT("needle"),
			substrMT("haystack"),
		}}, true},
		{"(foo)(?-s:.)*?(bar)", &andLineMatchTree{andMatchTree{[]matchTree{
			substrMT("foo"),
			substrMT("bar"),
		}}}, false},
		{"(foo)(?-s:.)*?[[:space:]](?-s:.)*?(bar)", &andMatchTree{[]matchTree{
			substrMT("foo"),
			substrMT("bar"),
		}}, false},
		{"(foo){2,}", substrMT("foo"), false},
		{"(...)(...)", &bruteForceMatchTree{}, false},
	}

	for _, c := range cases {
		r, err := syntax.Parse(c.in, syntax.Perl)
		if err != nil {
			t.Errorf("Parse(%q): %v", c.in, err)
			continue
		}
		d := indexData{}
		q := query.Regexp{
			Regexp: r,
		}
		gotQuery, isEq, _, _ := d.regexpToMatchTreeRecursive(q.Regexp, 3, q.FileName, q.CaseSensitive)
		if !reflect.DeepEqual(c.query, gotQuery) {
			printRegexp(t, r, 0)
			t.Errorf("regexpToQuery(%q): got %v, want %v", c.in, gotQuery, c.query)
		}
		if isEq != c.isEquivalent {
			printRegexp(t, r, 0)
			t.Errorf("regexpToQuery(%q): got %v, want %v", c.in, isEq, c.isEquivalent)
		}
	}
}