feat(plugin): add mini bar chart visualization to session summary (#1041)

packages/claude-code-plugin/hooks/lib/buddy_renderer.py

@@ -565,6 +565,96 @@ def _get_summary_header(key: str, language: str) -> str:
     return lang_headers.get(key, SUMMARY_HEADERS["en"].get(key, key))
 
 
+def render_bar_chart(
+    label: str,
+    value: int,
+    max_value: int,
+    width: int = 20,
+    color: str = "green",
+    ascii_mode: bool = False,
+) -> str:
+    """Render a single mini bar chart line (#1041).
+
+    Args:
+        label: Left-aligned label (e.g., "Edit", "Bash").
+        value: Current value to visualize.
+        max_value: Maximum value for full bar width.
+        width: Bar width in characters (default 20).
+        color: ANSI color name for the filled portion.
+        ascii_mode: If True, use ASCII characters instead of Unicode.
+
+    Returns:
+        Formatted bar chart line, e.g.:
+          Normal: "  Edit         ████████░░░░ 5"
+          ASCII:  "  Edit         [####........] 5"
+    """
+    if max_value <= 0 or value <= 0:
+        ratio = 0.0
+    else:
+        ratio = min(value / max_value, 1.0)
+
+    filled = int(ratio * width)
+    empty = width - filled
+
+    if ascii_mode:
+        bar = "[" + "#" * filled + "." * empty + "]"
+    else:
+        filled_bar = "\u2588" * filled + "\u2591" * empty
+        bar = _colorize(filled_bar, color)
+
+    return f"  {label:<12} {bar} {value}"
+
+
+def _render_bar_charts(
+    tool_names: Dict[str, int],
+    stats: Dict[str, Any],
+    ascii_mode: bool = False,
+) -> List[str]:
+    """Build bar chart lines from tool usage data (#1041).
+
+    Shows top tool distribution bars, normalized to the highest count.
+
+    Args:
+        tool_names: Dict of tool name → usage count.
+        stats: Session stats dict with files_changed, tool_count.
+        ascii_mode: Whether to use ASCII rendering.
+
+    Returns:
+        List of formatted bar chart lines.
+    """
+    if not tool_names:
+        return []
+
+    # Get top 3 tools by usage
+    sorted_tools = sorted(tool_names.items(), key=lambda x: x[1], reverse=True)
+    top_tools = sorted_tools[:3]
+
+    if not top_tools:
+        return []
+
+    max_val = top_tools[0][1]
+    if max_val <= 0:
+        return []
+
+    # Color mapping by tool type
+    tool_colors = {
+        "Edit": "yellow",
+        "Write": "yellow",
+        "Bash": "cyan",
+        "Read": "blue",
+        "Grep": "blue",
+        "Glob": "blue",
+        "Agent": "magenta",
+    }
+
+    lines: List[str] = []
+    for tool, count in top_tools:
+        color = tool_colors.get(tool, "green")
+        lines.append(render_bar_chart(tool, count, max_val, color=color, ascii_mode=ascii_mode))
+
+    return lines
+
+
 def render_session_summary(
     stats: Dict[str, Any],
     agents: List[Dict[str, Any]],
@@ -638,6 +728,13 @@ def render_session_summary(
         if one_line:
             parts.append(f"\U0001f4ac {one_line}")
 
+        # Bar chart visualization (#1041)
+        ascii_mode = bc.get("asciiMode", False)
+        charts = _render_bar_charts(tool_names, stats, ascii_mode=ascii_mode)
+        if charts:
+            parts.append("")
+            parts.extend(charts)
+
     # Active agents section
     if agents:
         header = _get_summary_header("agents", language)

packages/claude-code-plugin/hooks/test_buddy_renderer.py

@@ -16,6 +16,7 @@
     render_session_start,
     render_session_summary,
     render_returning_session,
+    render_bar_chart,
     get_buddy_config,
     type_text,
     _to_ascii,
@@ -704,6 +705,112 @@ def test_typing_mode_ascii(self, capsys, monkeypatch):
         assert "\u256d" not in captured.err
 
 
+class TestRenderBarChart:
+    """Tests for render_bar_chart — mini bar chart visualization (#1041)."""
+
+    def test_full_bar(self):
+        result = render_bar_chart("Edit", 10, 10, width=10)
+        assert "Edit" in result
+        assert "10" in result
+        assert "\u2588" * 10 in result  # ██████████
+
+    def test_half_bar(self):
+        result = render_bar_chart("Bash", 5, 10, width=10)
+        assert "\u2588" * 5 in result
+        assert "\u2591" * 5 in result
+
+    def test_zero_value(self):
+        result = render_bar_chart("Read", 0, 10, width=10)
+        assert "0" in result
+        assert "\u2591" * 10 in result  # all empty
+
+    def test_zero_max_value(self):
+        result = render_bar_chart("Read", 5, 0, width=10)
+        assert "5" in result
+        assert "\u2591" * 10 in result  # all empty (safe division)
+
+    def test_value_exceeds_max(self):
+        result = render_bar_chart("Edit", 15, 10, width=10)
+        assert "\u2588" * 10 in result  # capped at full
+
+    def test_ascii_mode(self):
+        result = render_bar_chart("Bash", 5, 10, width=10, ascii_mode=True)
+        assert "[" in result
+        assert "]" in result
+        assert "#" * 5 in result
+        assert "." * 5 in result
+
+    def test_ascii_mode_full(self):
+        result = render_bar_chart("Edit", 10, 10, width=10, ascii_mode=True)
+        assert "[##########]" in result
+
+    def test_ascii_mode_empty(self):
+        result = render_bar_chart("Read", 0, 10, width=10, ascii_mode=True)
+        assert "[..........]" in result
+
+    def test_label_alignment(self):
+        result = render_bar_chart("X", 5, 10, width=10)
+        # Label should be left-padded to 12 chars
+        assert "X " in result
+
+    def test_color_applied_in_normal_mode(self):
+        result = render_bar_chart("Edit", 5, 10, color="yellow")
+        assert ANSI_COLORS["yellow"] in result
+        assert ANSI_COLORS["reset"] in result
+
+    def test_no_color_in_ascii_mode(self):
+        result = render_bar_chart("Edit", 5, 10, color="yellow", ascii_mode=True)
+        assert ANSI_COLORS["yellow"] not in result
+
+
+class TestBarChartInSummary:
+    """Tests for bar chart integration in render_session_summary (#1041)."""
+
+    def test_bar_charts_appear_with_tool_names(self):
+        stats = {"duration_minutes": 10, "tool_count": 30, "files_changed": 5}
+        tool_names = {"Edit": 10, "Read": 15, "Bash": 5}
+        result = render_session_summary(stats, [], "casual", "en", tool_names=tool_names)
+        assert "\u2588" in result  # bar chart present
+        assert "Edit" in result
+        assert "Read" in result
+        assert "Bash" in result
+
+    def test_bar_charts_show_top_3_only(self):
+        stats = {"duration_minutes": 10, "tool_count": 50, "files_changed": 5}
+        tool_names = {"Edit": 10, "Read": 20, "Bash": 15, "Glob": 3, "Grep": 2}
+        result = render_session_summary(stats, [], "casual", "en", tool_names=tool_names)
+        # Top 3: Read(20), Bash(15), Edit(10)
+        assert "Read" in result
+        assert "Bash" in result
+        assert "Edit" in result
+
+    def test_no_bar_charts_without_tool_names(self):
+        stats = {"duration_minutes": 10, "tool_count": 5, "files_changed": 2}
+        result = render_session_summary(stats, [], "casual", "en")
+        assert "\u2588" not in result  # no bar chars
+
+    def test_bar_charts_ascii_mode(self):
+        bc = {
+            "name": "Buddy", "face": BUDDY_FACE,
+            "greeting": "", "farewell": "", "asciiMode": True,
+        }
+        stats = {"duration_minutes": 10, "tool_count": 20, "files_changed": 3}
+        tool_names = {"Edit": 8, "Read": 12}
+        result = render_session_summary(
+            stats, [], "casual", "en",
+            buddy_config=bc, tool_names=tool_names,
+        )
+        assert "[#" in result  # ASCII bar
+        assert "\u2588" not in result  # no Unicode bar
+
+    def test_empty_tool_names_no_charts(self):
+        stats = {"duration_minutes": 5, "tool_count": 0, "files_changed": 0}
+        result = render_session_summary(
+            stats, [], "casual", "en", tool_names={},
+        )
+        assert "\u2588" not in result
+
+
 if __name__ == "__main__":
     import pytest
     pytest.main([__file__, "-v"])