From 2eb5a432d2229788ce2fdb09f36c6f4bebdea813 Mon Sep 17 00:00:00 2001
From: Laria Carolin Chabowski <laria@laria.me>
Date: Fri, 7 Feb 2020 09:44:59 +0100
Subject: Initial commit

---
 src/Search/SearchResult.php | 160 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 160 insertions(+)
 create mode 100644 src/Search/SearchResult.php

(limited to 'src/Search/SearchResult.php')

diff --git a/src/Search/SearchResult.php b/src/Search/SearchResult.php
new file mode 100644
index 0000000..1abbb86
--- /dev/null
+++ b/src/Search/SearchResult.php
@@ -0,0 +1,160 @@
+<?php
+
+
+namespace Micropoly\Search;
+
+
+use LogicException;
+use Micropoly\DbQuery;
+use Micropoly\Esc;
+use Micropoly\Models\Note;
+use SQLite3;
+
+class SearchResult
+{
+    private Note $note;
+    private array $highlights = [];
+
+    private function __construct(Note $note, array $highlights)
+    {
+        $this->note = $note;
+        $this->highlights = $highlights;
+    }
+
+    /**
+     * @param SQLite3 $db
+     * @param SearchExpr $expr
+     * @return self[]
+     */
+    public static function search(SQLite3 $db, SearchExpr $expr): array
+    {
+        return $expr->countFTSQueries() === 1
+            ? self::searchFTS($db, $expr)
+            : self::searchComplex($db, $expr);
+    }
+
+    private static function searchComplex(SQLite3 $db, SearchExpr $expr): array
+    {
+        $sqlSearchExpr = $expr->toSQL("", false);
+
+        $query = new DbQuery("
+            SELECT
+                n.id
+            FROM notes n
+            INNER JOIN note_contents nc
+                ON nc.rowid = n.content_row
+            WHERE {$sqlSearchExpr->sql}
+        ");
+
+        foreach ($sqlSearchExpr->bindings as $k => $v)
+            $query->bind($k, $v);
+
+        $ids = array_map(fn ($row) => $row[0], $query->fetchRows($db));
+        $notes = Note::byIds($db, $ids);
+        return array_map(fn ($note) => new self($note, []), $notes);
+    }
+
+    private static function highlightRangeContains(array $range, int $point): bool
+    {
+        [$start, $end] = $range;
+        return $start <= $point && $point <= $end;
+    }
+
+    private static function areHighlightsOverlapping(array $a, array $b): bool
+    {
+        [$aStart, $aEnd] = $a;
+        [$bStart, $bEnd] = $b;
+
+        return self::highlightRangeContains($a, $bStart)
+            || self::highlightRangeContains($a, $bEnd)
+            || self::highlightRangeContains($b, $aStart)
+            || self::highlightRangeContains($b, $aEnd);
+    }
+
+    private static function parseOffsetsToHighlights(string $offsets): array
+    {
+        $offsets = explode(" ", $offsets);
+        $offsets = array_map("intval", $offsets);
+
+        $phraseMatches = count($offsets) / 4;
+
+        $highlights = [];
+        for ($i = 0; $i < $phraseMatches; $i++) {
+            $off = $offsets[$i * 4 + 2];
+            $len = $offsets[$i * 4 + 3];
+
+            if ($off < 0 || $len === 0)
+                continue;
+
+            $highlights[] = [$off, $off+$len-1];
+        }
+
+        usort($highlights, fn ($a, $b) => ($a[0] <=> $b[0]) ?: ($b[1] <=> $a[1]));
+
+        // merge overlapping areas
+        for ($i = count($highlights)-1; $i >= 0; $i--) {
+            for ($j = $i-1; $j >= 0; $j--) {
+                if (self::areHighlightsOverlapping($highlights[$i], $highlights[$j])) {
+                    [$iStart, $iEnd] = $highlights[$i];
+                    [$jStart, $jEnd] = $highlights[$j];
+
+                    $highlights[$j] = [min($iStart, $jStart), max($iEnd, $jEnd)];
+                    unset($highlights[$i]);
+                    break;
+                }
+            }
+        }
+
+        return array_merge($highlights); // array_merge here renumbers the keys
+    }
+
+    private static function searchFTS(SQLite3 $db, SearchExpr $expr)
+    {
+        $sqlSearchExpr = $expr->toSQL("", true);
+        $query = new DbQuery("
+            SELECT
+                n.id,
+                offsets(nc.note_contents) AS offsets
+            FROM notes n
+            INNER JOIN note_contents nc
+                ON nc.rowid = n.content_row
+            WHERE {$sqlSearchExpr->sql}
+        ");
+        foreach ($sqlSearchExpr->bindings as $k => $v)
+            $query->bind($k, $v);
+
+
+        $offsets = $query->fetchIndexedValues($db, "offsets", "id");
+
+        $notes = Note::byIds($db, array_keys($offsets));
+
+        $out = [];
+        foreach ($offsets as $id => $offString) {
+            if (!isset($notes[$id]))
+                throw new LogicException("Note '{$id}' not loaded but found?");
+
+            $out[] = new self($notes[$id], self::parseOffsetsToHighlights($offString));
+        }
+
+        return $out;
+    }
+
+    public function renderHighlightedContent(): string
+    {
+        $out = "";
+        $content = $this->note->getContent();
+        $lastOff = 0;
+        foreach ($this->highlights as [$start, $end]) {
+            $out .= Esc::e(substr($content, $lastOff, $start - $lastOff), Esc::HTML_WITH_BR);
+            $out .= '<b>' . Esc::e(substr($content, $start, $end - $start + 1), Esc::HTML_WITH_BR) . '</b>';
+
+            $lastOff = $end + 1;
+        }
+
+        $out .= Esc::e(substr($content, $lastOff), Esc::HTML_WITH_BR);
+
+        return $out;
+    }
+
+    public function getNote(): Note { return $this->note; }
+}
\ No newline at end of file
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