1#!/usr/local/bin/python3.8
2#
3# Electron Cash - lightweight Bitcoin client
4# Copyright (C) 2019 Axel Gembe <derago@gmail.com>
5#
6# Permission is hereby granted, free of charge, to any person
7# obtaining a copy of this software and associated documentation files
8# (the "Software"), to deal in the Software without restriction,
9# including without limitation the rights to use, copy, modify, merge,
10# publish, distribute, sublicense, and/or sell copies of the Software,
11# and to permit persons to whom the Software is furnished to do so,
12# subject to the following conditions:
13#
14# The above copyright notice and this permission notice shall be
15# included in all copies or substantial portions of the Software.
16#
17# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
21# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
22# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
23# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
24# SOFTWARE.
25
26from typing import List, Dict, Callable, Any
27from abc import ABC, abstractmethod
28
29from PyQt5.QtGui import QColor
30from PyQt5.QtCore import Qt
31
32from electrum.i18n import _
33from electrum.qrreader import QrCodeResult
34
35from electrum.gui.qt.util import ColorScheme, QColorLerp
36
37
38class QrReaderValidatorResult():
39    """
40    Result of a QR code validator
41    """
42
43    def __init__(self):
44        self.accepted: bool = False
45
46        self.message: str = None
47        self.message_color: QColor = None
48
49        self.simple_result : str = None
50
51        self.result_usable: Dict[QrCodeResult, bool] = {}
52        self.result_colors: Dict[QrCodeResult, QColor] = {}
53        self.result_messages: Dict[QrCodeResult, str] = {}
54
55        self.selected_results: List[QrCodeResult] = []
56
57
58class AbstractQrReaderValidator(ABC):
59    """
60    Abstract base class for QR code result validators.
61    """
62
63    @abstractmethod
64    def validate_results(self, results: List[QrCodeResult]) -> QrReaderValidatorResult:
65        """
66        Checks a list of QR code results for usable codes.
67        """
68
69class QrReaderValidatorCounting(AbstractQrReaderValidator):
70    """
71    This QR code result validator doesn't directly accept any results but maintains a dictionary
72    of detection counts in `result_counts`.
73    """
74
75    result_counts: Dict[QrCodeResult, int] = {}
76
77    def validate_results(self, results: List[QrCodeResult]) -> QrReaderValidatorResult:
78        res = QrReaderValidatorResult()
79
80        for result in results:
81            # Increment the detection count
82            if not result in self.result_counts:
83                self.result_counts[result] = 0
84            self.result_counts[result] += 1
85
86        # Search for missing results, iterate over a copy because the loop might modify the dict
87        for result in self.result_counts.copy():
88            # Count down missing results
89            if result in results:
90                continue
91            self.result_counts[result] -= 2
92            # When the count goes to zero, remove
93            if self.result_counts[result] < 1:
94                del self.result_counts[result]
95
96        return res
97
98class QrReaderValidatorColorizing(QrReaderValidatorCounting):
99    """
100    This QR code result validator doesn't directly accept any results but colorizes the results
101    based on the counts maintained by `QrReaderValidatorCounting`.
102    """
103
104    WEAK_COLOR: QColor = QColor(Qt.red)
105    STRONG_COLOR: QColor = QColor(Qt.green)
106
107    strong_count: int = 10
108
109    def validate_results(self, results: List[QrCodeResult]) -> QrReaderValidatorResult:
110        res = super().validate_results(results)
111
112        # Colorize the QR code results by their detection counts
113        for result in results:
114            # Enforce strong_count as upper limit
115            self.result_counts[result] = min(self.result_counts[result], self.strong_count)
116
117            # Interpolate between WEAK_COLOR and STRONG_COLOR based on count / strong_count
118            lerp_factor = (self.result_counts[result] - 1) / self.strong_count
119            lerped_color = QColorLerp(self.WEAK_COLOR, self.STRONG_COLOR, lerp_factor)
120            res.result_colors[result] = lerped_color
121
122        return res
123
124class QrReaderValidatorStrong(QrReaderValidatorColorizing):
125    """
126    This QR code result validator doesn't directly accept any results but passes every strong
127    detection in the return values `selected_results`.
128    """
129
130    def validate_results(self, results: List[QrCodeResult]) -> QrReaderValidatorResult:
131        res = super().validate_results(results)
132
133        for result in results:
134            if self.result_counts[result] >= self.strong_count:
135                res.selected_results.append(result)
136                break
137
138        return res
139
140class QrReaderValidatorCounted(QrReaderValidatorStrong):
141    """
142    This QR code result validator accepts a result as soon as there is at least `minimum` and at
143    most `maximum` QR code(s) with strong detection.
144    """
145
146    def __init__(self, minimum: int = 1, maximum: int = 1):
147        super().__init__()
148        self.minimum = minimum
149        self.maximum = maximum
150
151    def validate_results(self, results: List[QrCodeResult]) -> QrReaderValidatorResult:
152        res = super().validate_results(results)
153
154        num_results = len(res.selected_results)
155        if num_results < self.minimum:
156            if num_results > 0:
157                res.message = _('Too few QR codes detected.')
158                res.message_color = ColorScheme.RED.as_color()
159        elif num_results > self.maximum:
160            res.message = _('Too many QR codes detected.')
161            res.message_color = ColorScheme.RED.as_color()
162        else:
163            res.accepted = True
164            res.simple_result = (results and results[0].data) or ''  # hack added by calin just to take the first one
165
166        return res
167