feat: add pick_color_theme() UI and integration

engine/app.py

@@ -10,7 +10,7 @@ import termios
 import time
 import tty
 
-from engine import config, render
+from engine import config, render, themes
 from engine.fetch import fetch_all, fetch_poetry, load_cache, save_cache
 from engine.mic import MicMonitor
 from engine.ntfy import NtfyPoller
@@ -65,6 +65,28 @@ def _read_picker_key():
     return None
 
 
+def _draw_color_picker(themes_list, selected):
+    """Draw the color theme picker menu.
+
+    Args:
+        themes_list: List of (theme_id, Theme) tuples from THEME_REGISTRY.items()
+        selected: Index of currently selected theme (0-2)
+    """
+    print(CLR, end="")
+    print()
+
+    print(f"  {G_HI}▼ COLOR THEME{RST} {W_GHOST}─ ↑/↓ or j/k to move, Enter/q to select{RST}")
+    print(f"  {W_GHOST}{'─' * (tw() - 4)}{RST}\n")
+
+    for i, (theme_id, theme) in enumerate(themes_list):
+        prefix = "  ▶ " if i == selected else "    "
+        color = G_HI if i == selected else ""
+        reset = "" if i == selected else W_GHOST
+        print(f"{prefix}{color}{theme.name}{reset}")
+
+    print()
+
+
 def _normalize_preview_rows(rows):
     """Trim shared left padding and trailing spaces for stable on-screen previews."""
     non_empty = [r for r in rows if r.strip()]
@@ -131,6 +153,50 @@ def _draw_font_picker(faces, selected):
         print(f"    {shown}")
 
 
+def pick_color_theme():
+    """Interactive color theme picker. Defaults to 'green' if not TTY.
+
+    Displays a menu of available themes and lets user select with arrow keys.
+    Non-interactive environments (piped stdin, CI) silently default to green.
+    """
+    # Non-interactive fallback
+    if not sys.stdin.isatty():
+        config.set_active_theme("green")
+        return
+
+    # Interactive picker
+    themes_list = list(themes.THEME_REGISTRY.items())
+    selected = 0
+
+    fd = sys.stdin.fileno()
+    old_settings = termios.tcgetattr(fd)
+    try:
+        tty.setcbreak(fd)
+        while True:
+            _draw_color_picker(themes_list, selected)
+            key = _read_picker_key()
+            if key == "up":
+                selected = max(0, selected - 1)
+            elif key == "down":
+                selected = min(len(themes_list) - 1, selected + 1)
+            elif key == "enter":
+                break
+            elif key == "interrupt":
+                raise KeyboardInterrupt
+    finally:
+        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
+
+    selected_theme_id = themes_list[selected][0]
+    config.set_active_theme(selected_theme_id)
+
+    theme_name = themes_list[selected][1].name
+    print(f"  {G_DIM}> using {theme_name}{RST}")
+    time.sleep(0.8)
+    print(CLR, end="")
+    print(CURSOR_OFF, end="")
+    print()
+
+
 def pick_font_face():
     """Interactive startup picker for selecting a face from repo OTF files."""
     if not config.FONT_PICKER:
@@ -262,6 +328,7 @@ def main():
     w = tw()
     print(CLR, end="")
     print(CURSOR_OFF, end="")
+    pick_color_theme()
     pick_font_face()
     w = tw()
     print()