// 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 shards

import (
	"bytes"
	"context"
	"fmt"
	"log"
	"os"
	"runtime"
	"testing"
	"time"

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

type crashSearcher struct{}

func (s *crashSearcher) Search(ctx context.Context, q query.Q, opts *zoekt.SearchOptions) (*zoekt.SearchResult, error) {
	panic("search")
}

func (s *crashSearcher) List(ctx context.Context, q query.Q) (*zoekt.RepoList, error) {
	panic("list")
}

func (s *crashSearcher) Stats() (*zoekt.RepoStats, error) {
	return &zoekt.RepoStats{}, nil
}

func (s *crashSearcher) Close() {}

func (s *crashSearcher) String() string { return "crashSearcher" }

func TestCrashResilience(t *testing.T) {
	out := &bytes.Buffer{}
	log.SetOutput(out)
	defer log.SetOutput(os.Stderr)
	ss := newShardedSearcher(2)
	ss.shards = map[string]rankedShard{
		"x": rankedShard{Searcher: &crashSearcher{}},
	}

	q := &query.Substring{Pattern: "hoi"}
	opts := &zoekt.SearchOptions{}
	if res, err := ss.Search(context.Background(), q, opts); err != nil {
		t.Fatalf("Search: %v", err)
	} else if res.Stats.Crashes != 1 {
		t.Errorf("got stats %#v, want crashes = 1", res.Stats)
	}

	if res, err := ss.List(context.Background(), q); err != nil {
		t.Fatalf("List: %v", err)
	} else if res.Crashes != 1 {
		t.Errorf("got result %#v, want crashes = 1", res)
	}
}

type rankSearcher struct {
	rank uint16
}

func (s *rankSearcher) Close() {
}

func (s *rankSearcher) String() string {
	return ""
}

func (s *rankSearcher) Search(ctx context.Context, q query.Q, opts *zoekt.SearchOptions) (*zoekt.SearchResult, error) {
	select {
	case <-ctx.Done():
		return &zoekt.SearchResult{}, nil
	default:
	}

	// Ugly, but without sleep it's too fast, and we can't
	// simulate the cutoff.
	time.Sleep(time.Millisecond)
	return &zoekt.SearchResult{
		Files: []zoekt.FileMatch{
			{
				FileName: fmt.Sprintf("f%d", s.rank),
				Score:    float64(s.rank),
			},
		},
		Stats: zoekt.Stats{
			MatchCount: 1,
		},
	}, nil
}

func (s *rankSearcher) List(ctx context.Context, q query.Q) (*zoekt.RepoList, error) {
	return &zoekt.RepoList{
		Repos: []*zoekt.RepoListEntry{
			{Repository: zoekt.Repository{Rank: s.rank}},
		},
	}, nil
}

func TestOrderByShard(t *testing.T) {
	ss := newShardedSearcher(1)

	n := 10 * runtime.GOMAXPROCS(0)
	for i := 0; i < n; i++ {
		ss.replace(fmt.Sprintf("shard%d", i),
			&rankSearcher{
				rank: uint16(i),
			})
	}

	if res, err := ss.Search(context.Background(), &query.Substring{Pattern: "bla"}, &zoekt.SearchOptions{}); err != nil {
		t.Errorf("Search: %v", err)
	} else if len(res.Files) != n {
		t.Fatalf("empty options: got %d results, want %d", len(res.Files), n)
	}

	opts := zoekt.SearchOptions{
		TotalMaxMatchCount: 3,
	}
	res, err := ss.Search(context.Background(), &query.Substring{Pattern: "bla"}, &opts)
	if err != nil {
		t.Errorf("Search: %v", err)
	}

	if len(res.Files) < opts.TotalMaxMatchCount {
		t.Errorf("got %d results, want %d", len(res.Files), opts.TotalMaxMatchCount)
	}
	if len(res.Files) == n {
		t.Errorf("got %d results, want < %d", len(res.Files), n)
	}
	for i, f := range res.Files {
		rev := n - 1 - i
		want := fmt.Sprintf("f%d", rev)
		got := f.FileName

		if got != want {
			t.Logf("%d: got %q, want %q", i, got, want)
		}
	}
}

type memSeeker struct {
	data []byte
}

func (s *memSeeker) Name() string {
	return "memseeker"
}

func (s *memSeeker) Close() {}
func (s *memSeeker) Read(off, sz uint32) ([]byte, error) {
	return s.data[off : off+sz], nil
}

func (s *memSeeker) Size() (uint32, error) {
	return uint32(len(s.data)), nil
}

func TestUnloadIndex(t *testing.T) {
	b, err := zoekt.NewIndexBuilder(nil)
	if err != nil {
		t.Fatalf("NewIndexBuilder: %v", err)
	}

	for i, d := range []zoekt.Document{{
		Name:    "filename",
		Content: []byte("needle needle needle"),
	}} {
		if err := b.Add(d); err != nil {
			t.Fatalf("Add %d: %v", i, err)
		}
	}

	var buf bytes.Buffer
	b.Write(&buf)
	indexBytes := buf.Bytes()
	indexFile := &memSeeker{indexBytes}
	searcher, err := zoekt.NewSearcher(indexFile)
	if err != nil {
		t.Fatalf("NewSearcher: %v", err)
	}

	ss := newShardedSearcher(2)
	ss.replace("key", searcher)

	var opts zoekt.SearchOptions
	q := &query.Substring{Pattern: "needle"}
	res, err := ss.Search(context.Background(), q, &opts)
	if err != nil {
		t.Fatalf("Search(%s): %v", q, err)
	}

	forbidden := byte(29)
	for i := range indexBytes {
		// non-ASCII
		indexBytes[i] = forbidden
	}

	for _, f := range res.Files {
		if bytes.Contains(f.Content, []byte{forbidden}) {
			t.Errorf("found %d in content %q", forbidden, f.Content)
		}
		if bytes.Contains(f.Checksum, []byte{forbidden}) {
			t.Errorf("found %d in checksum %q", forbidden, f.Checksum)
		}

		for _, l := range f.LineMatches {
			if bytes.Contains(l.Line, []byte{forbidden}) {
				t.Errorf("found %d in line %q", forbidden, l.Line)
			}
		}
	}
}