.claude/CLAUDE.MD

@@ -1,120 +0,0 @@
-# Claude Code – Working Agreement
-
-## Workflow: Plan → Write Tests → Implement → Verify
-
-### 1. Plan First
-Before writing any code, produce an explicit plan:
-- Restate the requirement in your own words to confirm understanding.
-- List every file you intend to create or modify.
-- Identify risks or unknowns upfront.
-- Wait for confirmation **only** when the plan reveals an ambiguity that cannot be resolved from context. Otherwise proceed immediately.
-
-### 2. Write Tests
-Before implementing, write tests that should cover the new behaviour.
-Only write tests for the new behaviour.
-
-### 3. Implement
-Follow the plan. Do not add scope beyond what was agreed.
-
-### 4. Verify Every Requirement
-After implementation, go through each requirement one-by-one and confirm it is satisfied:
-- Run the relevant tests (unit, integration, or build check) for every changed module.
-- If a requirement **cannot** be fulfilled, do **not** silently skip it — document it immediately (see *Unresolved Requirements* below).
-
----
-
-## No Code Without Verification (Testing)
-
-- Every new behaviour must be covered by at least one automated test before the task is considered done.
-- Every bug fix must be accompanied by a regression test that fails before the fix and passes after.
-- Run `./gradlew :modules:<module>:test` (or the appropriate Gradle task) and confirm a green build before marking work complete.
-- If a test cannot be written for a legitimate reason, document it in `docs/unresolved.md` with an explanation.
-
----
-
-## Automatic Bug Fixing
-
-- When a test or build step fails, attempt to fix the root cause immediately — do **not** ask for permission.
-- Apply the fix, re-run the verification, and continue until green.
-- If the same failure persists after **three** fix attempts, stop, log the issue in `docs/unresolved.md`, and surface a concise summary.
-
----
-
-## Unresolved Requirements → `docs/unresolved.md`
-
-When a requirement or bug cannot be resolved, append an entry to `docs/unresolved.md`:
-
-```markdown
-## [YYYY-MM-DD] <Short title>
-
-**Requirement / Bug:**
-<What was requested or what failed>
-
-**Root Cause (if known):**
-<Why it cannot be resolved right now>
-
-**Attempted Fixes:**
-1. <What was tried>
-2. …
-
-**Suggested Next Step:**
-<What a human engineer should investigate>
-```
-
-Create the file if it does not exist. Never delete existing entries.
-
----
-
-## Project Structure
-
-```
-.                        ← Repository root (multi-project Gradle setup)
-├── build.gradle.kts     ← Root build file (shared plugins, dependency versions)
-├── settings.gradle.kts  ← Gradle settings (declares all subprojects)
-├── modules/             ← One subdirectory per microservice
-│   └── <service>/
-│       ├── build.gradle.kts
-│       └── src/
-└── docs/                ← Architecture Decision Records, API docs, unresolved issues
-    └── unresolved.md
-```
-
-### Conventions
-- All microservices live under `modules/{service-name}`. Never place service code in the root.
-- Shared configuration (dependency versions, plugin setup) belongs in the **root** `build.gradle.kts` or in `buildSrc` / a version catalog.
-- `settings.gradle.kts` must include every module via `include(":modules:<service>")`.
-- Architecture decisions go in `docs/adr/` as numbered Markdown files (`ADR-001-<title>.md`).
-- API contracts live in `/docs/api/`.
-- Unit tests extend `AnyFunSuite with Matchers` — no `@Test` annotations, no `: Unit` requirement
-- Integration tests use `@QuarkusTest` with JUnit 5 — `@Test` methods must be explicitly typed `: Unit`
-- Always exclude scala-library from Quarkus deps to avoid Scala 2 conflicts
-
-## Coverage Conventions
-- Branch coverage must be at least 90% - unless there is a good reason not to.
-- Line coverage must be at least 95% - unless there is a good reason not to.
-- Method coverage must be at least 90% - unless there is a good reason not to.
-- To check coverage use jacoco-reporter/scoverage_coverage_gaps.py modules/{service}/build/reports/scoverageTest/scoverage.xml
-- IMPORTANT: modules/{service}/build/reports/scoverage/scoverage.xml is not used for coverage TEST calculation. Do not use it.
-
-## Agent Routing Rules
-
-### Use agents in PARALLEL when:
-- Tasks touch different, independent microservices
-- No shared files or state between tasks
-- Example: "implement service-user AND service-orders simultaneously"
-
-### Use agents SEQUENTIALLY when:
-- Tasks have dependencies (architect → implementer → test-writer)
-- Shared API contracts are involved
-- Example: design API first, then implement, then test
-
-## Quick-Reference Checklist
-
-Before considering any task done, confirm:
-
-- [ ] Plan was written and requirements restated
-- [ ] All planned files were created / modified
-- [ ] Automated tests cover the new behaviour
-- [ ] `./gradlew build` (or scoped task) is green
-- [ ] Each requirement has been explicitly verified
-- [ ] Any unresolved items are logged in `docs/unresolved.md`

CLAUDE.md

@@ -1,58 +1,54 @@
-# CLAUDE.md
+# CLAUDE.md — NowChessSystems
 
-This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+## Stack
+Scala 3.5.x · Quarkus + quarkus-scala3 · Hibernate/Jakarta · Lanterna TUI · K8s + ArgoCD + Kargo · Frontend TBD (Vite/React/Angular/Vue)
 
-## Build & Test Commands
+## Structure
+```
+build.gradle.kts / settings.gradle.kts   # root; include(":modules:<svc>") per service
+modules/<svc>/build.gradle.kts + src/
+docs/adr/  docs/api/  docs/unresolved.md
+```
+Versions in root `extra["VERSIONS"]`; modules read via `rootProject.extra["VERSIONS"] as Map<String,String>`.
 
+## Commands
 ```bash
-# Build everything
 ./gradlew build
-
-# Build a single module
-./gradlew :modules:<service>:build
-
-# Run tests for a single module
-./gradlew :modules:<service>:test
-
-# Run a specific test class
-./gradlew :modules:<service>:test --tests "de.nowchess.<service>.<ClassName>"
+./gradlew :modules:<svc>:build|test
+./gradlew :modules:<svc>:test --tests "de.nowchess.<svc>.<Class>"
 ```
 
-The only current module is `core` (`modules/core`).
+## Workflow
+1. **Plan** — restate requirement, list files, flag risks. Proceed unless genuine ambiguity.
+2. **Tests first** — cover only new behaviour.
+3. **Implement** — no scope creep.
+4. **Verify** — check each requirement; confirm green build.
 
-## Architecture
+## Scala/Quarkus Rules
+- `given`/`using` only (no `implicit`); `Option`/`Either`/`Try` (no `null`/`.get`)
+- `jakarta.*` only; reactive I/O (`Uni`/`Multi`), no blocking on event loop
+- Always exclude `org.scala-lang:scala-library` from Quarkus BOM
+- Unit tests: `extends AnyFunSuite with Matchers` — no `@Test`, no `: Unit`
+- Integration tests: `@QuarkusTest` + JUnit 5 — `@Test` methods need explicit `: Unit`
 
-**NowChessSystems** is a chess platform built as a Scala 3 + Quarkus microservice system.
+## Coverage
+Line ≥ 95% · Branch ≥ 90% · Method ≥ 90% (document exceptions)
+Check: `jacoco-reporter/scoverage_coverage_gaps.py modules/{svc}/build/reports/scoverageTest/scoverage.xml`
+⚠️ Use `scoverageTest/`, NOT `scoverage/`.
 
-- Multi-module Gradle project; every service lives under `modules/{service-name}`.
-- Shared dependency versions live in the root `build.gradle.kts` under `extra["VERSIONS"]`.
-- Each module reads versions via `rootProject.extra["VERSIONS"] as Map<String, String>`.
-- `settings.gradle.kts` must `include(":modules:<service>")` for every module.
+## Bug Fixing
+Fix failures immediately without asking. After 3 failed attempts → log in `docs/unresolved.md` + surface summary.
 
-### Stack (ADR-001)
-| Layer | Technology |
-|---|---|
-| Language | Scala 3.5.x |
-| Backend framework | Quarkus + `quarkus-scala3` extension |
-| Persistence | Hibernate / Jakarta Persistence |
-| Frontend (TBD) | Vite; React/Angular/Vue under evaluation |
-| TUI | Lanterna |
-| Container orchestration | Kubernetes + ArgoCD + Kargo |
+## Agents (new service)
+Sequential: architect → scala-implementer → test-writer → gradle-builder → code-reviewer (review only, no self-fix)
+Parallel: only when services are fully independent (no shared contracts/state).
 
-### Key Scala 3 / Quarkus Rules
-- Use `given`/`using`, not `implicit` (no Scala 2 idioms).
-- Use `Option`/`Either`/`Try`, never `null` or `.get`.
-- Jakarta annotations only (`jakarta.*`), never `javax.*`.
-- Use reactive types (`Uni`, `Multi`) for I/O; no blocking calls on the event loop.
-- **Always exclude `org.scala-lang:scala-library` from Quarkus BOM** to avoid Scala 2 conflicts.
-- **Unit tests use `extends AnyFunSuite with Matchers`** — ScalaTest DSL, no `@Test` annotations needed.
-- **Integration tests use `@QuarkusTest` with JUnit 5** — explicit `: Unit` return type still required on `@Test` methods.
+## Unresolved (`docs/unresolved.md`)
+Append only, never delete:
+```
+## [YYYY-MM-DD] <title>
+**Requirement/Bug:** **Root Cause:** **Attempted Fixes:** **Next Step:**
+```
 
-### Agent Workflow (for new services)
-1. **architect** → writes OpenAPI contract to `docs/api/{service}.yaml` and ADR to `docs/adr/`.
-2. **scala-implementer** → reads contract, implements service under `modules/{service}/`.
-3. **test-writer** → writes `@QuarkusTest` integration tests and `AnyFunSuite with Matchers` unit tests.
-4. **gradle-builder** → resolves any build/dependency issues.
-5. **code-reviewer** → reviews; reports findings back without self-fixing.
-
-Detailed working agreement (plan/verify/unresolved workflow) is in `.claude/CLAUDE.MD`.
+## Done Checklist
+- [ ] Plan written · files created/modified · tests green · requirements verified · unresolved logged

jacoco-reporter/jacoco_coverage_gaps.py

@@ -1,411 +0,0 @@
-#!/usr/bin/env python3
-"""
-JaCoCo Coverage Gap Reporter
-Parses a JaCoCo XML report and outputs missing line & branch (conditional)
-coverage in a structured format that Claude Code agents can act on directly.
-
-Usage:
-    python jacoco_coverage_gaps.py <jacoco-report.xml> [--min-coverage 80]
-    python jacoco_coverage_gaps.py <jacoco-report.xml> --output json
-    python jacoco_coverage_gaps.py <jacoco-report.xml> --output markdown
-    python jacoco_coverage_gaps.py <jacoco-report.xml> --output agent   (default)
-"""
-
-import xml.etree.ElementTree as ET
-import sys
-import argparse
-import json
-from pathlib import Path
-from dataclasses import dataclass, field
-from typing import Optional
-
-
-# ---------------------------------------------------------------------------
-# Data classes
-# ---------------------------------------------------------------------------
-
-@dataclass
-class LineCoverage:
-    line_number: int
-    hits: int                   # 0 = not executed
-    branch_total: int = 0       # 0 = not a branch point
-    branch_covered: int = 0
-
-    @property
-    def is_uncovered(self) -> bool:
-        return self.hits == 0
-
-    @property
-    def is_partial_branch(self) -> bool:
-        return self.branch_total > 0 and self.branch_covered < self.branch_total
-
-
-@dataclass
-class MethodCoverage:
-    name: str
-    descriptor: str
-    first_line: Optional[int]
-    missed_instructions: int
-    covered_instructions: int
-    missed_branches: int
-    covered_branches: int
-    uncovered_lines: list[int] = field(default_factory=list)
-    partial_branch_lines: list[int] = field(default_factory=list)
-
-    @property
-    def total_branches(self) -> int:
-        return self.missed_branches + self.covered_branches
-
-    @property
-    def is_fully_covered(self) -> bool:
-        return self.missed_instructions == 0 and self.missed_branches == 0
-
-    @property
-    def branch_coverage_pct(self) -> float:
-        total = self.total_branches
-        return 100.0 * self.covered_branches / total if total else 100.0
-
-    @property
-    def line_coverage_pct(self) -> float:
-        total = self.missed_instructions + self.covered_instructions
-        return 100.0 * self.covered_instructions / total if total else 100.0
-
-
-@dataclass
-class ClassCoverage:
-    class_name: str             # e.g. com/example/Foo
-    source_file: Optional[str]
-    methods: list[MethodCoverage] = field(default_factory=list)
-    all_lines: list[LineCoverage] = field(default_factory=list)
-
-    @property
-    def java_class_name(self) -> str:
-        return self.class_name.replace("/", ".")
-
-    @property
-    def source_path(self) -> Optional[str]:
-        """Best-guess relative source path."""
-        if self.source_file:
-            package = "/".join(self.class_name.split("/")[:-1])
-            return f"src/main/java/{package}/{self.source_file}" if package else f"src/main/java/{self.source_file}"
-        return None
-
-    @property
-    def uncovered_lines(self) -> list[int]:
-        return sorted({l.line_number for l in self.all_lines if l.is_uncovered})
-
-    @property
-    def partial_branch_lines(self) -> list[int]:
-        return sorted({l.line_number for l in self.all_lines if l.is_partial_branch})
-
-    @property
-    def missed_branches(self) -> int:
-        return sum(max(l.branch_total - l.branch_covered, 0) for l in self.all_lines)
-
-    @property
-    def total_branches(self) -> int:
-        return sum(l.branch_total for l in self.all_lines)
-
-    @property
-    def covered_branches(self) -> int:
-        return self.total_branches - self.missed_branches
-
-    @property
-    def missed_lines(self) -> int:
-        return len(self.uncovered_lines)
-
-    @property
-    def total_lines(self) -> int:
-        return len(self.all_lines)
-
-    @property
-    def covered_lines(self) -> int:
-        return self.total_lines - self.missed_lines
-
-    @property
-    def has_gaps(self) -> bool:
-        return bool(self.uncovered_lines or self.partial_branch_lines)
-
-
-# ---------------------------------------------------------------------------
-# Parser
-# ---------------------------------------------------------------------------
-
-def parse_jacoco_xml(xml_path: str) -> list[ClassCoverage]:
-    """Parse a JaCoCo XML report into ClassCoverage objects."""
-    tree = ET.parse(xml_path)
-    root = tree.getroot()
-
-    results: list[ClassCoverage] = []
-
-    for package in root.iter("package"):
-        for cls_elem in package.findall("class"):
-            class_name = cls_elem.get("name", "")
-            source_file = cls_elem.get("sourcefilename")
-
-            # Build method map from <method> children
-            methods: list[MethodCoverage] = []
-            for m in cls_elem.findall("method"):
-                counters = {c.get("type"): c for c in m.findall("counter")}
-
-                def _missed(t): return int(counters[t].get("missed", 0)) if t in counters else 0
-                def _covered(t): return int(counters[t].get("covered", 0)) if t in counters else 0
-
-                methods.append(MethodCoverage(
-                    name=m.get("name", ""),
-                    descriptor=m.get("desc", ""),
-                    first_line=int(m.get("line")) if m.get("line") else None,
-                    missed_instructions=_missed("INSTRUCTION"),
-                    covered_instructions=_covered("INSTRUCTION"),
-                    missed_branches=_missed("BRANCH"),
-                    covered_branches=_covered("BRANCH"),
-                ))
-
-            cc = ClassCoverage(
-                class_name=class_name,
-                source_file=source_file,
-                methods=methods,
-            )
-
-            # Per-line data lives in the matching <sourcefile> element
-            source_file_elem = package.find(f"sourcefile[@name='{source_file}']") if source_file else None
-            if source_file_elem is not None:
-                for line_elem in source_file_elem.findall("line"):
-                    nr = int(line_elem.get("nr", 0))
-                    mi = int(line_elem.get("mi", 0))   # missed instructions
-                    ci = int(line_elem.get("ci", 0))   # covered instructions
-                    mb = int(line_elem.get("mb", 0))   # missed branches
-                    cb = int(line_elem.get("cb", 0))   # covered branches
-                    hits = ci  # ci > 0 means line was executed at least once
-                    cc.all_lines.append(LineCoverage(
-                        line_number=nr,
-                        hits=hits,
-                        branch_total=mb + cb,
-                        branch_covered=cb,
-                    ))
-
-            if cc.has_gaps:
-                results.append(cc)
-
-    return results
-
-
-# ---------------------------------------------------------------------------
-# Formatters
-# ---------------------------------------------------------------------------
-
-def _compact_ranges(numbers: list[int]) -> str:
-    """Turn [1,2,3,5,7,8,9] -> '1-3, 5, 7-9'"""
-    if not numbers:
-        return ""
-    ranges = []
-    start = prev = numbers[0]
-    for n in numbers[1:]:
-        if n == prev + 1:
-            prev = n
-        else:
-            ranges.append(f"{start}-{prev}" if start != prev else str(start))
-            start = prev = n
-    ranges.append(f"{start}-{prev}" if start != prev else str(start))
-    return ", ".join(ranges)
-
-
-def format_agent(classes: list[ClassCoverage]) -> str:
-    """
-    Output optimised for Claude Code agents:
-    – structured, machine-readable yet human-legible
-    – uses file paths and line numbers agents can act on
-    – groups by file, sorts by severity (most gaps first)
-    """
-    lines: list[str] = []
-    lines.append("# JaCoCo Coverage Gaps — Agent Action Report")
-    lines.append("")
-    lines.append("## Summary")
-    total_uncovered = sum(c.missed_lines for c in classes)
-    total_partial = sum(len(c.partial_branch_lines) for c in classes)
-    total_missed_branches = sum(c.missed_branches for c in classes)
-    lines.append(f"- Files with gaps : {len(classes)}")
-    lines.append(f"- Uncovered lines : {total_uncovered}")
-    lines.append(f"- Partial branches: {total_partial} lines affected")
-    lines.append(f"- Missed branches : {total_missed_branches} branch paths")
-    lines.append("")
-    lines.append("---")
-    lines.append("")
-    lines.append("## Files Requiring Tests")
-    lines.append("")
-    lines.append("> Each entry lists the SOURCE FILE PATH, the LINE NUMBERS that need")
-    lines.append("> coverage, and the METHODS that contain those gaps.")
-    lines.append("> Write or extend unit/integration tests to exercise these paths.")
-    lines.append("")
-
-    # Sort: most uncovered lines first
-    sorted_classes = sorted(classes, key=lambda c: -(c.missed_lines + len(c.partial_branch_lines)))
-
-    for cls in sorted_classes:
-        source = cls.source_path or f"(source unknown) {cls.java_class_name}"
-        lines.append(f"### `{source}`")
-        lines.append(f"**Class**: `{cls.java_class_name}`")
-        lines.append("")
-
-        if cls.uncovered_lines:
-            lines.append(f"#### ❌ Uncovered Lines")
-            lines.append(f"Lines not executed at all: `{_compact_ranges(cls.uncovered_lines)}`")
-            lines.append("")
-            lines.append("**Methods with uncovered lines:**")
-            for method in cls.methods:
-                uncov = [l for l in cls.uncovered_lines
-                         if method.first_line and l >= method.first_line]
-                # heuristic: only attribute if there are uncovered lines near the method start
-                if method.missed_instructions > 0:
-                    sig = f"`{method.name}{method.descriptor}`"
-                    pct = method.line_coverage_pct
-                    lines.append(f"  - {sig} — {pct:.0f}% instruction coverage")
-            lines.append("")
-
-        if cls.partial_branch_lines:
-            lines.append(f"#### ⚠️  Partial Branch Coverage (Missing Conditional Paths)")
-            lines.append(f"Lines where not all branches are taken: `{_compact_ranges(cls.partial_branch_lines)}`")
-            lines.append("")
-            lines.append("**Methods with branch gaps:**")
-            for method in cls.methods:
-                if method.missed_branches > 0:
-                    sig = f"`{method.name}{method.descriptor}`"
-                    pct = method.branch_coverage_pct
-                    missing = method.missed_branches
-                    lines.append(f"  - {sig} — {pct:.0f}% branch coverage ({missing} branch path(s) never taken)")
-            lines.append("")
-
-        lines.append("**Action**: Add tests that exercise the above lines/branches.")
-        lines.append("")
-        lines.append("---")
-        lines.append("")
-
-    lines.append("## Quick Reference: All Uncovered Locations")
-    lines.append("")
-    lines.append("Copy-paste friendly list for IDE navigation or grep:")
-    lines.append("")
-    lines.append("```")
-    for cls in sorted_classes:
-        src = cls.source_path or cls.java_class_name
-        if cls.uncovered_lines:
-            for ln in cls.uncovered_lines:
-                lines.append(f"{src}:{ln}  # uncovered line")
-        if cls.partial_branch_lines:
-            for ln in cls.partial_branch_lines:
-                lines.append(f"{src}:{ln}  # partial branch")
-    lines.append("```")
-
-    return "\n".join(lines)
-
-
-def format_json(classes: list[ClassCoverage]) -> str:
-    out = []
-    for cls in classes:
-        out.append({
-            "class": cls.java_class_name,
-            "source_path": cls.source_path,
-            "uncovered_lines": cls.uncovered_lines,
-            "partial_branch_lines": cls.partial_branch_lines,
-            "missed_branches": cls.missed_branches,
-            "methods": [
-                {
-                    "name": m.name,
-                    "descriptor": m.descriptor,
-                    "first_line": m.first_line,
-                    "line_coverage_pct": round(m.line_coverage_pct, 1),
-                    "branch_coverage_pct": round(m.branch_coverage_pct, 1),
-                    "missed_branches": m.missed_branches,
-                    "missed_instructions": m.missed_instructions,
-                }
-                for m in cls.methods
-                if not m.is_fully_covered
-            ],
-        })
-    return json.dumps(out, indent=2)
-
-
-def format_markdown(classes: list[ClassCoverage]) -> str:
-    lines: list[str] = []
-    lines.append("# JaCoCo Missing Coverage Report\n")
-    for cls in sorted(classes, key=lambda c: cls.java_class_name):
-        lines.append(f"## {cls.java_class_name}")
-        if cls.source_path:
-            lines.append(f"**File**: `{cls.source_path}`\n")
-        if cls.uncovered_lines:
-            lines.append(f"**Uncovered lines**: {_compact_ranges(cls.uncovered_lines)}\n")
-        if cls.partial_branch_lines:
-            lines.append(f"**Partial branches at lines**: {_compact_ranges(cls.partial_branch_lines)}\n")
-        lines.append("| Method | Line Coverage | Branch Coverage | Missed Branches |")
-        lines.append("|--------|--------------|-----------------|-----------------|")
-        for m in cls.methods:
-            if not m.is_fully_covered:
-                lines.append(
-                    f"| `{m.name}` | {m.line_coverage_pct:.0f}% | "
-                    f"{m.branch_coverage_pct:.0f}% | {m.missed_branches} |"
-                )
-        lines.append("")
-    return "\n".join(lines)
-
-
-# ---------------------------------------------------------------------------
-# Entry point
-# ---------------------------------------------------------------------------
-
-def main() -> None:
-    parser = argparse.ArgumentParser(
-        description="Report missing line & branch coverage from a JaCoCo XML report."
-    )
-    parser.add_argument("xml_file", help="Path to jacoco.xml report file")
-    parser.add_argument(
-        "--output", "-o",
-        choices=["agent", "json", "markdown"],
-        default="json",
-        help="Output format (default: agent)",
-    )
-    parser.add_argument(
-        "--min-coverage",
-        type=float,
-        default=0.0,
-        help="Only report classes below this %% line coverage (0 = report all gaps)",
-    )
-    parser.add_argument(
-        "--package-filter", "-p",
-        default=None,
-        help="Only report classes in this package prefix (e.g. com/example/service)",
-    )
-    args = parser.parse_args()
-
-    xml_path = Path(args.xml_file)
-    if not xml_path.exists():
-        print(f"ERROR: File not found: {xml_path}", file=sys.stderr)
-        sys.exit(1)
-
-    classes = parse_jacoco_xml(str(xml_path))
-
-    # Apply package filter
-    if args.package_filter:
-        prefix = args.package_filter.replace(".", "/")
-        classes = [c for c in classes if c.class_name.startswith(prefix)]
-
-    # Apply min-coverage filter
-    if args.min_coverage > 0:
-        def _line_pct(c: ClassCoverage) -> float:
-            total = c.total_lines
-            return 100.0 * c.covered_lines / total if total else 100.0
-
-        classes = [c for c in classes if _line_pct(c) < args.min_coverage]
-
-    if not classes:
-        print("✅ No coverage gaps found matching the given filters.")
-        return
-
-    if args.output == "agent":
-        print(format_agent(classes))
-    elif args.output == "json":
-        print(format_json(classes))
-    elif args.output == "markdown":
-        print(format_markdown(classes))
-
-
-if __name__ == "__main__":
-    main()

modules/core/src/main/scala/de/nowchess/chess/logic/MoveValidator.scala

@@ -132,29 +132,24 @@ object MoveValidator:
     val kingSq = Square(File.E, rank)
     val enemy  = color.opposite
 
-    if ctx.board.pieceAt(kingSq) != Some(Piece(color, PieceType.King)) then return Set.empty
-    if GameRules.isInCheck(ctx.board, color) then return Set.empty
+    if !ctx.board.pieceAt(kingSq).contains(Piece(color, PieceType.King)) ||
+       GameRules.isInCheck(ctx.board, color) then Set.empty
+    else
+      val kingsideSq = Option.when(
+        rights.kingSide &&
+        ctx.board.pieceAt(Square(File.H, rank)).contains(Piece(color, PieceType.Rook)) &&
+        List(Square(File.F, rank), Square(File.G, rank)).forall(s => ctx.board.pieceAt(s).isEmpty) &&
+        !List(Square(File.F, rank), Square(File.G, rank)).exists(s => isAttackedBy(ctx.board, s, enemy))
+      )(Square(File.G, rank))
 
-    var result = Set.empty[Square]
+      val queensideSq = Option.when(
+        rights.queenSide &&
+        ctx.board.pieceAt(Square(File.A, rank)).contains(Piece(color, PieceType.Rook)) &&
+        List(Square(File.B, rank), Square(File.C, rank), Square(File.D, rank)).forall(s => ctx.board.pieceAt(s).isEmpty) &&
+        !List(Square(File.D, rank), Square(File.C, rank)).exists(s => isAttackedBy(ctx.board, s, enemy))
+      )(Square(File.C, rank))
 
-    if rights.kingSide then
-      val rookSq  = Square(File.H, rank)
-      val transit = List(Square(File.F, rank), Square(File.G, rank))
-      if ctx.board.pieceAt(rookSq).contains(Piece(color, PieceType.Rook)) &&
-         transit.forall(s => ctx.board.pieceAt(s).isEmpty) &&
-         !transit.exists(s => isAttackedBy(ctx.board, s, enemy)) then
-        result += Square(File.G, rank)
-
-    if rights.queenSide then
-      val rookSq       = Square(File.A, rank)
-      val emptySquares = List(Square(File.B, rank), Square(File.C, rank), Square(File.D, rank))
-      val transitSqs   = List(Square(File.D, rank), Square(File.C, rank))
-      if ctx.board.pieceAt(rookSq).contains(Piece(color, PieceType.Rook)) &&
-         emptySquares.forall(s => ctx.board.pieceAt(s).isEmpty) &&
-         !transitSqs.exists(s => isAttackedBy(ctx.board, s, enemy)) then
-        result += Square(File.C, rank)
-
-    result
+      kingsideSq.toSet ++ queensideSq.toSet
 
   def legalTargets(ctx: GameContext, from: Square): Set[Square] =
     ctx.board.pieceAt(from) match

modules/core/src/main/scala/de/nowchess/chess/view/Renderer.scala

@@ -11,21 +11,18 @@ object Renderer:
   private val AnsiBlackPiece  = "\u001b[30m"         // black text
 
   def render(board: Board): String =
-    val sb = new StringBuilder
-    sb.append("  a  b  c  d  e  f  g  h\n")
-    for rank <- (0 until 8).reverse do
-      sb.append(s"${rank + 1} ")
-      for file <- 0 until 8 do
-        val sq          = Square(File.values(file), Rank.values(rank))
-        val isLightSq   = (file + rank) % 2 != 0
-        val bgColor     = if isLightSq then AnsiLightSquare else AnsiDarkSquare
-        val cellContent = board.pieceAt(sq) match
+    val rows = (0 until 8).reverse.map { rank =>
+      val cells = (0 until 8).map { file =>
+        val sq        = Square(File.values(file), Rank.values(rank))
+        val isLightSq = (file + rank) % 2 != 0
+        val bgColor   = if isLightSq then AnsiLightSquare else AnsiDarkSquare
+        board.pieceAt(sq) match
           case Some(piece) =>
             val fgColor = if piece.color == Color.White then AnsiWhitePiece else AnsiBlackPiece
             s"$bgColor$fgColor ${piece.unicode} $AnsiReset"
           case None =>
             s"$bgColor   $AnsiReset"
-        sb.append(cellContent)
-      sb.append(s" ${rank + 1}\n")
-    sb.append("  a  b  c  d  e  f  g  h\n")
-    sb.toString
+      }.mkString
+      s"${rank + 1} $cells ${rank + 1}"
+    }.mkString("\n")
+    s"  a  b  c  d  e  f  g  h\n$rows\n  a  b  c  d  e  f  g  h\n"