summary refs log tree commit diff
path: root/src/CompletionProxyModel.h
blob: e0f00788b6d0e04e5b9198821c95573e668803f3 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
// SPDX-FileCopyrightText: Nheko Contributors
//
// SPDX-License-Identifier: GPL-3.0-or-later

#pragma once

// Class for showing a limited amount of completions at a time

#include <QAbstractProxyModel>

enum class ElementRank
{
    first,
    second
};

template<typename Key, typename Value>
struct trie
{
    std::vector<Value> values;
    std::map<Key, trie> next;

    template<ElementRank r>
    void insert(const QVector<Key> &keys, const Value &v)
    {
        auto t = this;
        for (const auto k : keys) {
            t = &t->next[k];
        }

        if constexpr (r == ElementRank::first) {
            t->values.insert(t->values.begin(), v);
        } else if constexpr (r == ElementRank::second) {
            t->values.push_back(v);
        }
    }

    std::vector<Value> valuesAndSubvalues(size_t limit = -1) const
    {
        std::vector<Value> ret;
        if (limit < 200)
            ret.reserve(limit);

        for (const auto &v : values) {
            if (ret.size() >= limit)
                return ret;
            else
                ret.push_back(v);
        }

        for (const auto &[k, t] : next) {
            (void)k;
            if (ret.size() >= limit)
                return ret;
            else {
                auto temp = t.valuesAndSubvalues(limit - ret.size());
                for (auto &&v : temp) {
                    if (ret.size() >= limit)
                        return ret;

                    if (std::find(ret.begin(), ret.end(), v) == ret.end()) {
                        ret.push_back(std::move(v));
                    }
                }
            }
        }

        return ret;
    }

    std::vector<Value> search(const QVector<Key> &keys, //< TODO(Nico): replace this with a span
                              size_t result_count_limit,
                              size_t max_edit_distance_ = 2) const
    {
        std::vector<Value> ret;
        if (!result_count_limit)
            return ret;

        if (keys.isEmpty())
            return valuesAndSubvalues(result_count_limit);

        auto append = [&ret, result_count_limit](std::vector<Value> &&in) {
            for (auto &&v : in) {
                if (ret.size() >= result_count_limit)
                    return;

                if (std::find(ret.begin(), ret.end(), v) == ret.end()) {
                    ret.push_back(std::move(v));
                }
            }
        };

        auto limit = [&ret, result_count_limit] {
            return std::min(result_count_limit, (result_count_limit - ret.size()) * 2);
        };

        // Try first exact matches, then with maximum errors
        for (size_t max_edit_distance = 0;
             max_edit_distance <= max_edit_distance_ && ret.size() < result_count_limit;
             max_edit_distance += 1) {
            if (max_edit_distance && ret.size() < result_count_limit) {
                max_edit_distance -= 1;

                // swap chars case
                if (keys.size() >= 2) {
                    auto t = this;
                    for (int i = 1; i >= 0; i--) {
                        if (auto e = t->next.find(keys[i]); e != t->next.end()) {
                            t = &e->second;
                        } else {
                            t = nullptr;
                            break;
                        }
                    }

                    if (t) {
                        append(t->search(keys.mid(2), limit(), max_edit_distance));
                    }
                }

                // insert case
                for (const auto &[k, t] : this->next) {
                    if (k == keys[0])
                        continue;
                    if (ret.size() >= limit())
                        break;

                    // insert
                    append(t.search(keys, limit(), max_edit_distance));
                }

                // delete character case
                append(this->search(keys.mid(1), limit(), max_edit_distance));

                // substitute case
                for (const auto &[k, t] : this->next) {
                    if (k == keys[0])
                        continue;
                    if (ret.size() >= limit())
                        break;

                    // substitute
                    append(t.search(keys.mid(1), limit(), max_edit_distance));
                }

                max_edit_distance += 1;
            }

            if (auto e = this->next.find(keys[0]); e != this->next.end()) {
                append(e->second.search(keys.mid(1), limit(), max_edit_distance));
            }
        }

        return ret;
    }
};

class CompletionProxyModel final : public QAbstractProxyModel
{
    Q_OBJECT
    Q_PROPERTY(QString searchString READ searchString WRITE setSearchString NOTIFY newSearchString)
public:
    CompletionProxyModel(QAbstractItemModel *model,
                         int max_mistakes       = 2,
                         size_t max_completions = 30,
                         QObject *parent        = nullptr);

    void invalidate();

    QHash<int, QByteArray> roleNames() const override;
    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
    int columnCount(const QModelIndex &) const override;

    QModelIndex mapFromSource(const QModelIndex &sourceIndex) const override;
    QModelIndex mapToSource(const QModelIndex &proxyIndex) const override;

    QModelIndex
    index(int row, int column, const QModelIndex &parent = QModelIndex()) const override;
    QModelIndex parent(const QModelIndex &) const override;

public slots:
    QVariant completionAt(int i) const;

    void setSearchString(const QString &s);
    QString searchString() const { return searchString_; }

signals:
    void newSearchString(QString);

private:
    QString searchString_;
    trie<uint, int> trie_;
    std::vector<int> mapping;
    int maxMistakes_;
    size_t max_completions_;
};