Add SkillProgressionAnomalyAnalyser

Compares consecutive perks-snapshot rows per Steam ID and emits a
SkillProgressionAnomalyProblem for any single skill whose level gained
more than THRESHOLD_DELTA between two snapshots. Login/Logout/LevelUp
event rows are skipped via a perk-pair regex check on the bracketed
event field.

Threshold of 3 reflects PZ's slow leveling pace: typical session bridges
should not produce four-or-more level jumps in a single skill. The
constant is documented inline so operators can tune for modded XP
servers without touching analysis logic.

Synthetic fixture extended with a PlayerSuspect Steam ID carrying two
snapshots: Strength jumps 2 -> 10 (delta +8, triggers), Fitness jumps
2 -> 8 (+6, triggers), Maintenance jumps 0 -> 3 (+3, exactly at
threshold, does NOT trigger). The existing single-snapshot players
remain noise-free.

src/Analyser/ProjectZomboid/SkillProgressionAnomalyAnalyser.php

@@ -0,0 +1,87 @@
+<?php
+
+namespace IndifferentKetchup\Codex\Analyser\ProjectZomboid;
+
+use IndifferentKetchup\Codex\Analyser\Analyser;
+use IndifferentKetchup\Codex\Analysis\Analysis;
+use IndifferentKetchup\Codex\Analysis\AnalysisInterface;
+use IndifferentKetchup\Codex\Analysis\ProjectZomboid\SkillProgressionAnomalyProblem;
+use IndifferentKetchup\Codex\Pattern\ProjectZomboid\PerkPattern;
+
+/**
+ * Walks PerkLog entries, parses each perks-snapshot row into a
+ * skill->level dict, and compares consecutive snapshots per Steam ID. If
+ * any single skill gained more than THRESHOLD_DELTA levels between
+ * snapshots, emits a SkillProgressionAnomalyProblem for that
+ * (player, skill) pair.
+ *
+ * Login/Logout/LevelUp event rows are skipped — they have a single token
+ * in the event field rather than a comma-separated list of Skill=N pairs.
+ */
+class SkillProgressionAnomalyAnalyser extends Analyser
+{
+    /**
+     * Maximum plausible single-skill gain between two consecutive snapshots
+     * of the same player. Project Zomboid skill leveling is slow: most
+     * skills require thousands of XP per level, and even maxed grinding
+     * setups don't routinely produce four-or-more level jumps in a single
+     * session bridge. Set to 3 as a baseline; if production logs surface
+     * frequent legitimate jumps of 4 (e.g. on heavily modded XP servers),
+     * raise via subclass override or tune downward to catch finer abuse.
+     */
+    public const int THRESHOLD_DELTA = 3;
+
+    public function analyse(): AnalysisInterface
+    {
+        $analysis = new Analysis();
+        $analysis->setLog($this->log);
+
+        $snapshots = [];
+        foreach ($this->log as $entry) {
+            $text = (string) $entry;
+            if (preg_match(PerkPattern::FIELDS, $text, $m) !== 1) {
+                continue;
+            }
+            if (preg_match(PerkPattern::PERK_PAIR, $m['event']) !== 1) {
+                continue;
+            }
+
+            preg_match_all(PerkPattern::PERK_PAIR, $m['event'], $pairs, PREG_SET_ORDER);
+            $skills = [];
+            foreach ($pairs as $pair) {
+                $skills[$pair['skill']] = (int) $pair['level'];
+            }
+
+            $snapshots[$m['steamid']][] = [
+                'time' => $entry->getTime() ?? 0,
+                'player' => $m['player'],
+                'skills' => $skills,
+            ];
+        }
+
+        foreach ($snapshots as $steamId => $playerSnapshots) {
+            usort($playerSnapshots, static fn($a, $b) => $a['time'] <=> $b['time']);
+
+            for ($i = 1; $i < count($playerSnapshots); $i++) {
+                $prev = $playerSnapshots[$i - 1];
+                $curr = $playerSnapshots[$i];
+
+                foreach ($curr['skills'] as $skill => $currLevel) {
+                    $prevLevel = $prev['skills'][$skill] ?? 0;
+                    $delta = $currLevel - $prevLevel;
+                    if ($delta > self::THRESHOLD_DELTA) {
+                        $analysis->addInsight((new SkillProgressionAnomalyProblem())
+                            ->setSteamId($steamId)
+                            ->setPlayer($curr['player'])
+                            ->setSkill($skill)
+                            ->setFromLevel($prevLevel)
+                            ->setToLevel($currLevel)
+                            ->setDelta($delta));
+                    }
+                }
+            }
+        }
+
+        return $analysis;
+    }
+}

src/Analysis/ProjectZomboid/SkillProgressionAnomalyProblem.php

@@ -0,0 +1,107 @@
+<?php
+
+namespace IndifferentKetchup\Codex\Analysis\ProjectZomboid;
+
+use IndifferentKetchup\Codex\Analysis\InsightInterface;
+use IndifferentKetchup\Codex\Analysis\Problem;
+
+/**
+ * Problem emitted by SkillProgressionAnomalyAnalyser when a single skill
+ * gained more than the configured threshold between two consecutive
+ * snapshots of the same player. Coalesced by (Steam ID, skill).
+ */
+class SkillProgressionAnomalyProblem extends Problem
+{
+    private string $steamId = '';
+    private string $player = '';
+    private string $skill = '';
+    private int $fromLevel = 0;
+    private int $toLevel = 0;
+    private int $delta = 0;
+
+    public function setSteamId(string $steamId): static
+    {
+        $this->steamId = $steamId;
+        return $this;
+    }
+
+    public function setPlayer(string $player): static
+    {
+        $this->player = $player;
+        return $this;
+    }
+
+    public function setSkill(string $skill): static
+    {
+        $this->skill = $skill;
+        return $this;
+    }
+
+    public function setFromLevel(int $level): static
+    {
+        $this->fromLevel = $level;
+        return $this;
+    }
+
+    public function setToLevel(int $level): static
+    {
+        $this->toLevel = $level;
+        return $this;
+    }
+
+    public function setDelta(int $delta): static
+    {
+        $this->delta = $delta;
+        return $this;
+    }
+
+    public function getSteamId(): string
+    {
+        return $this->steamId;
+    }
+
+    public function getPlayer(): string
+    {
+        return $this->player;
+    }
+
+    public function getSkill(): string
+    {
+        return $this->skill;
+    }
+
+    public function getFromLevel(): int
+    {
+        return $this->fromLevel;
+    }
+
+    public function getToLevel(): int
+    {
+        return $this->toLevel;
+    }
+
+    public function getDelta(): int
+    {
+        return $this->delta;
+    }
+
+    public function getMessage(): string
+    {
+        return sprintf(
+            'Player %s (%s) gained %d levels of %s between snapshots (%d to %d).',
+            $this->player,
+            $this->steamId,
+            $this->delta,
+            $this->skill,
+            $this->fromLevel,
+            $this->toLevel
+        );
+    }
+
+    public function isEqual(InsightInterface $insight): bool
+    {
+        return $insight instanceof self
+            && $insight->getSteamId() === $this->steamId
+            && $insight->getSkill() === $this->skill;
+    }
+}

src/Log/ProjectZomboid/ProjectZomboidPerkLog.php

@@ -3,7 +3,7 @@
 namespace IndifferentKetchup\Codex\Log\ProjectZomboid;
 
 use IndifferentKetchup\Codex\Analyser\AnalyserInterface;
-use IndifferentKetchup\Codex\Analyser\PatternAnalyser;
+use IndifferentKetchup\Codex\Analyser\ProjectZomboid\SkillProgressionAnomalyAnalyser;
 use IndifferentKetchup\Codex\Detective\FilenameDetector;
 use IndifferentKetchup\Codex\Detective\WeightedSinglePatternDetector;
 use IndifferentKetchup\Codex\Parser\ParserInterface;
@@ -22,7 +22,7 @@ class ProjectZomboidPerkLog extends ProjectZomboidEventLog
 
     public static function getDefaultAnalyser(): AnalyserInterface
     {
-        return new PatternAnalyser();
+        return new SkillProgressionAnomalyAnalyser();
     }
 
     public static function getDetectors(): array

test/src/Games/ProjectZomboid/fixtures/perk-minimal.txt

@@ -4,3 +4,7 @@
 [16-04-26 18:29:15.823] [76561198000000002][Player2][1010,2010,0][Cooking=2, Fitness=10, Strength=10, Blunt=10, Axe=0, Lightfoot=4, Nimble=4, Sprinting=7, Sneak=2, Woodwork=6, Aiming=5, Reloading=4, Farming=0, Fishing=0, Trapping=0, PlantScavenging=0, Doctor=2, Electricity=5, Blacksmith=8, MetalWelding=10, Mechanics=10, Spear=0, Maintenance=7, SmallBlade=0, LongBlade=0, SmallBlunt=0, Tailoring=0, Tracking=0, Husbandry=0, FlintKnapping=0, Masonry=0, Pottery=0, Carving=0, Butchering=0, Glassmaking=0, Side_L=0, Side_R=0, ProstFamiliarity=0][Hours Survived: 50].
 [16-04-26 18:30:02.500] [76561198000000003][AdminUser][1020,2020,0][Logout][Hours Survived: 75].
 [16-04-26 19:15:00.000] [76561198000000001][Player1][1003,2003,1][LevelUp][Hours Survived: 101].
+[16-04-26 18:30:00.000] [76561198000000004][PlayerSuspect][1030,2030,0][Login][Hours Survived: 10].
+[16-04-26 18:30:00.000] [76561198000000004][PlayerSuspect][1030,2030,0][Cooking=2, Fitness=2, Strength=2, Blunt=0, Axe=0, Lightfoot=0, Nimble=0, Sprinting=0, Sneak=0, Woodwork=0, Aiming=0, Reloading=0, Farming=0, Fishing=0, Trapping=0, PlantScavenging=0, Doctor=0, Electricity=0, Blacksmith=0, MetalWelding=0, Mechanics=0, Spear=0, Maintenance=0, SmallBlade=0, LongBlade=0, SmallBlunt=0, Tailoring=0, Tracking=0, Husbandry=0, FlintKnapping=0, Masonry=0, Pottery=0, Carving=0, Butchering=0, Glassmaking=0, Side_L=0, Side_R=0, ProstFamiliarity=0][Hours Survived: 10].
+[16-04-26 22:00:00.000] [76561198000000004][PlayerSuspect][1031,2031,0][Login][Hours Survived: 12].
+[16-04-26 22:00:00.000] [76561198000000004][PlayerSuspect][1031,2031,0][Cooking=2, Fitness=8, Strength=10, Blunt=0, Axe=0, Lightfoot=0, Nimble=0, Sprinting=0, Sneak=0, Woodwork=0, Aiming=0, Reloading=0, Farming=0, Fishing=0, Trapping=0, PlantScavenging=0, Doctor=0, Electricity=0, Blacksmith=0, MetalWelding=0, Mechanics=0, Spear=0, Maintenance=3, SmallBlade=0, LongBlade=0, SmallBlunt=0, Tailoring=0, Tracking=0, Husbandry=0, FlintKnapping=0, Masonry=0, Pottery=0, Carving=0, Butchering=0, Glassmaking=0, Side_L=0, Side_R=0, ProstFamiliarity=0][Hours Survived: 12].

test/tests/Games/ProjectZomboid/Analyser/PerkLogAnalysisTest.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace IndifferentKetchup\Codex\Test\Tests\Games\ProjectZomboid\Analyser;
+
+use IndifferentKetchup\Codex\Analyser\ProjectZomboid\SkillProgressionAnomalyAnalyser;
+use IndifferentKetchup\Codex\Analysis\ProjectZomboid\SkillProgressionAnomalyProblem;
+use IndifferentKetchup\Codex\Log\File\PathLogFile;
+use IndifferentKetchup\Codex\Log\ProjectZomboid\ProjectZomboidPerkLog;
+use PHPUnit\Framework\TestCase;
+
+class PerkLogAnalysisTest extends TestCase
+{
+    private function fixturePath(): string
+    {
+        return __DIR__ . '/../../../../src/Games/ProjectZomboid/fixtures/perk-minimal.txt';
+    }
+
+    public function testFlagsSkillsThatExceedDeltaThreshold(): void
+    {
+        $log = (new ProjectZomboidPerkLog())->setLogFile(new PathLogFile($this->fixturePath()));
+        $log->parse();
+        $analysis = $log->analyse();
+
+        $problems = $analysis->getFilteredInsights(SkillProgressionAnomalyProblem::class);
+
+        $skills = array_map(fn($p) => $p->getSkill(), $problems);
+        sort($skills);
+
+        $this->assertSame(['Fitness', 'Strength'], $skills);
+
+        foreach ($problems as $problem) {
+            $this->assertSame('76561198000000004', $problem->getSteamId());
+            $this->assertSame('PlayerSuspect', $problem->getPlayer());
+        }
+    }
+
+    public function testDeltaAtThresholdDoesNotTrigger(): void
+    {
+        $log = (new ProjectZomboidPerkLog())->setLogFile(new PathLogFile($this->fixturePath()));
+        $log->parse();
+        $analysis = $log->analyse();
+
+        $problems = $analysis->getFilteredInsights(SkillProgressionAnomalyProblem::class);
+        foreach ($problems as $problem) {
+            $this->assertNotSame('Maintenance', $problem->getSkill());
+        }
+    }
+
+    public function testSinglePlayerWithOneSnapshotProducesNoProblem(): void
+    {
+        $log = (new ProjectZomboidPerkLog())->setLogFile(new PathLogFile($this->fixturePath()));
+        $log->parse();
+        $analysis = $log->analyse();
+
+        $problems = $analysis->getFilteredInsights(SkillProgressionAnomalyProblem::class);
+        foreach ($problems as $problem) {
+            $this->assertNotSame('76561198000000001', $problem->getSteamId());
+            $this->assertNotSame('76561198000000002', $problem->getSteamId());
+        }
+    }
+
+    public function testThresholdConstantIsDocumentedAndPositive(): void
+    {
+        $this->assertGreaterThan(0, SkillProgressionAnomalyAnalyser::THRESHOLD_DELTA);
+    }
+}

test/tests/Games/ProjectZomboid/Log/ProjectZomboidPerkLogTest.php

@@ -20,7 +20,7 @@ class ProjectZomboidPerkLogTest extends TestCase
         $log = (new ProjectZomboidPerkLog())->setLogFile(new PathLogFile($this->fixturePath()));
         $log->parse();
 
-        $this->assertCount(6, $log->getEntries());
+        $this->assertCount(10, $log->getEntries());
     }
 
     public function testFieldsRegexHandlesEventRow(): void