1<?php
2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
16
17/**
18 * This file contains the code to analyse all the responses to a particular
19 * question.
20 *
21 * @package    core_question
22 * @copyright  2013 Open University
23 * @author     Jamie Pratt <me@jamiep.org>
24 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
25 */
26
27namespace core_question\statistics\responses;
28defined('MOODLE_INTERNAL') || die();
29
30/**
31 * Analysis for possible responses for parts of a question. It is up to a question type designer to decide on how many parts their
32 * question has. See {@link \question_type::get_possible_responses()} and sub classes where the sub parts and response classes are
33 * defined.
34 *
35 * A sub part might represent a sub question embedded in the question for example in a matching question there are
36 * several sub parts. A numeric question with a unit might be divided into two sub parts for the purposes of response analysis
37 * or the question type designer might decide to treat the answer, both the numeric and unit part,
38 * as a whole for the purposes of response analysis.
39 *
40 * - There is a separate data structure for each question or sub question's analysis
41 * {@link \core_question\statistics\responses\analysis_for_question}
42 * or {@link \core_question\statistics\responses\analysis_for_question_all_tries}.
43 * - There are separate analysis for each variant in this top level instance.
44 * - Then there are class instances representing the analysis of each of the sub parts of each variant of the question.
45 * {@link \core_question\statistics\responses\analysis_for_subpart}.
46 * - Then within the sub part analysis there are response class analysis
47 * {@link \core_question\statistics\responses\analysis_for_class}.
48 * - Then within each class analysis there are analysis for each actual response
49 * {@link \core_question\statistics\responses\analysis_for_actual_response}.
50 *
51 * @package    core_question
52 * @copyright  2014 The Open University
53 * @author     James Pratt me@jamiep.org
54 * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
55 */
56class analysis_for_question {
57
58    /**
59     * Constructor method.
60     *
61     * @param array[] Two index array, first index is unique string for each sub question part,
62     *                    the second string index is the 'class' that sub-question part can be classified into.
63     *                    Value in array is instance of {@link \question_possible_response}
64     *                    This is the return value from {@link \question_type::get_possible_responses()}
65     *                    see that method for fuller documentation.
66     */
67    public function __construct(array $possiblereponses = null) {
68        if ($possiblereponses !== null) {
69            $this->possibleresponses = $possiblereponses;
70        }
71    }
72
73    /**
74     * @var array[] See description above in constructor method.
75     */
76    protected $possibleresponses = array();
77
78    /**
79     * A multidimensional array whose first index is variant no and second index is subpart id, array contents are of type
80     * {@link analysis_for_subpart}.
81     *
82     * @var array[]
83     */
84    protected $subparts = array();
85
86    /**
87     * Initialise data structure for response analysis of one variant.
88     *
89     * @param int $variantno
90     */
91    protected function initialise_stats_for_variant($variantno) {
92        $this->subparts[$variantno] = array();
93        foreach ($this->possibleresponses as $subpartid => $classes) {
94            $this->subparts[$variantno][$subpartid] = new analysis_for_subpart($classes);
95        }
96    }
97
98    /**
99     * Variant nos found in this question's attempt data.
100     *
101     * @return int[]
102     */
103    public function get_variant_nos() {
104        return array_keys($this->subparts);
105    }
106
107    /**
108     * Unique ids for sub parts.
109     *
110     * @param int $variantno
111     * @return string[]
112     */
113    public function get_subpart_ids($variantno) {
114        return array_keys($this->subparts[$variantno]);
115    }
116
117    /**
118     * Get the response counts etc. for variant $variantno, question sub part $subpartid.
119     *
120     * Or if there is no recorded analysis yet then initialise the data structure for that part of the analysis and return the
121     * initialised analysis objects.
122     *
123     * @param int    $variantno
124     * @param string $subpartid id for sub part.
125     * @return analysis_for_subpart
126     */
127    public function get_analysis_for_subpart($variantno, $subpartid) {
128        if (!isset($this->subparts[$variantno])) {
129            $this->initialise_stats_for_variant($variantno);
130        }
131        if (!isset($this->subparts[$variantno][$subpartid])) {
132            debugging('Unexpected sub-part id ' . $subpartid .
133                    ' encountered.');
134            $this->subparts[$variantno][$subpartid] = new analysis_for_subpart();
135        }
136        return $this->subparts[$variantno][$subpartid];
137    }
138
139    /**
140     * Used to work out what kind of table is needed to display stats.
141     *
142     * @return bool whether this question has (a subpart with) more than one response class.
143     */
144    public function has_multiple_response_classes() {
145        foreach ($this->get_variant_nos() as $variantno) {
146            foreach ($this->get_subpart_ids($variantno) as $subpartid) {
147                if ($this->get_analysis_for_subpart($variantno, $subpartid)->has_multiple_response_classes()) {
148                    return true;
149                }
150            }
151        }
152        return false;
153    }
154
155    /**
156     * Used to work out what kind of table is needed to display stats.
157     *
158     * @return bool whether this analysis has more than one subpart.
159     */
160    public function has_subparts() {
161        foreach ($this->get_variant_nos() as $variantno) {
162            if (count($this->get_subpart_ids($variantno)) > 1) {
163                return true;
164            }
165        }
166        return false;
167    }
168
169    /**
170     * @return bool Does this response analysis include counts for responses for multiple tries of the question?
171     */
172    public function has_multiple_tries_data() {
173        return false;
174    }
175
176    /**
177     * What is the highest number of tries at this question?
178     *
179     * @return int always 1 as this class is for analysing only one try.
180     */
181    public function get_maximum_tries() {
182        return 1;
183    }
184
185
186    /**
187     * Takes an array of {@link \question_classified_response} and adds counts of the responses to the sub parts and classes.
188     *
189     * @param int                             $variantno
190     * @param \question_classified_response[] $responseparts keys are sub-part id.
191     */
192    public function count_response_parts($variantno, $responseparts) {
193        foreach ($responseparts as $subpartid => $responsepart) {
194            $this->get_analysis_for_subpart($variantno, $subpartid)->count_response($responsepart);
195        }
196    }
197
198    /**
199     * @param \qubaid_condition $qubaids    which question usages have been analysed.
200     * @param string            $whichtries which tries have been analysed?
201     * @param int               $questionid which question.
202     */
203    public function cache($qubaids, $whichtries, $questionid) {
204        foreach ($this->get_variant_nos() as $variantno) {
205            foreach ($this->get_subpart_ids($variantno) as $subpartid) {
206                $analysisforsubpart = $this->get_analysis_for_subpart($variantno, $subpartid);
207                $analysisforsubpart->cache($qubaids, $whichtries, $questionid, $variantno, $subpartid);
208            }
209        }
210    }
211
212    /**
213     * @return bool whether this analysis has a response class with more than one
214     *      different actual response, or if the actual response is different from
215     *      the model response.
216     */
217    public function has_actual_responses() {
218        foreach ($this->get_variant_nos() as $variantno) {
219            foreach ($this->get_subpart_ids($variantno) as $subpartid) {
220                if ($this->get_analysis_for_subpart($variantno, $subpartid)->has_actual_responses()) {
221                    return true;
222                }
223            }
224        }
225        return false;
226    }
227
228}
229