Added Merlin to examples

Author: willmcgugan

examples/merlin.py

@@ -0,0 +1,173 @@
+from __future__ import annotations
+
+import random
+from datetime import timedelta
+from time import monotonic
+
+from textual import events
+from textual.app import App, ComposeResult
+from textual.containers import Grid
+from textual.reactive import var
+from textual.renderables.gradient import LinearGradient
+from textual.widget import Widget
+from textual.widgets import Digits, Label, Switch
+
+# A nice rainbow of colors.
+COLORS = [
+    "#881177",
+    "#aa3355",
+    "#cc6666",
+    "#ee9944",
+    "#eedd00",
+    "#99dd55",
+    "#44dd88",
+    "#22ccbb",
+    "#00bbcc",
+    "#0099cc",
+    "#3366bb",
+    "#663399",
+]
+
+
+# Maps a switch number on to other switch numbers, which should be toggled.
+TOGGLES: dict[int, tuple[int, ...]] = {
+    1: (2, 4, 5),
+    2: (1, 3),
+    3: (2, 5, 6),
+    4: (1, 7),
+    5: (2, 4, 6, 8),
+    6: (3, 9),
+    7: (4, 5, 8),
+    8: (7, 9),
+    9: (5, 6, 8),
+}
+
+
+class LabelSwitch(Widget):
+    """Switch with a numeric label."""
+
+    DEFAULT_CSS = """
+    LabelSwitch Label {
+        text-align: center;
+        width: 1fr;       
+        text-style: bold;         
+    }
+
+    LabelSwitch Label#label-5 {
+        color: $text-disabled;
+    }
+    """
+
+    def __init__(self, switch_no: int) -> None:
+        self.switch_no = switch_no
+        super().__init__()
+
+    def compose(self) -> ComposeResult:
+        """Compose the label and a switch."""
+        yield Label(str(self.switch_no), id=f"label-{self.switch_no}")
+        yield Switch(id=f"switch-{self.switch_no}", name=str(self.switch_no))
+
+
+class Timer(Digits):
+    """Displays a timer that stops when you win."""
+
+    DEFAULT_CSS = """
+    Timer {
+        text-align: center;
+        width: auto;
+        margin: 2 8;
+        color: $warning;
+    }
+    """
+    start_time = var(0.0)
+    running = var(True)
+
+    def on_mount(self) -> None:
+        """Start the timer on mount."""
+        self.start_time = monotonic()
+        self.set_interval(1, self.tick)
+        self.tick()
+
+    def tick(self) -> None:
+        """Called from `set_interval` to update the clock."""
+        if self.start_time == 0 or not self.running:
+            return
+        time_elapsed = timedelta(seconds=int(monotonic() - self.start_time))
+        self.update(str(time_elapsed))
+
+
+class MerlinApp(App):
+    """A simple reproduction of one game on the Merlin hand held console."""
+
+    CSS = """
+    Screen {
+        align: center middle;   
+    }
+
+    Screen.-win {
+        background: transparent;
+    }
+
+    Screen.-win Timer {
+        color: $success;
+    }    
+    
+    Grid {
+        width: auto;
+        height: auto;
+        border: thick $primary;
+        padding: 1 2;
+        grid-size: 3 3;
+        grid-rows: auto;
+        grid-columns: auto;
+        grid-gutter: 1 1;
+        background: $surface;
+    }
+    """
+
+    def render(self) -> LinearGradient:
+        """Renders a gradient, when the background is transparent."""
+        stops = [(i / (len(COLORS) - 1), c) for i, c in enumerate(COLORS)]
+        return LinearGradient(30.0, stops)
+
+    def compose(self) -> ComposeResult:
+        """Compose a timer, and a grid of 9 switches."""
+        yield Timer()
+        with Grid():
+            for switch in (7, 8, 9, 4, 5, 6, 1, 2, 3):
+                yield LabelSwitch(switch)
+
+    def on_mount(self) -> None:
+        """Randomize the switches on mount."""
+        for switch_no in range(1, 10):
+            if random.randint(0, 1):
+                self.query_one(f"#switch-{switch_no}", Switch).toggle()
+
+    def check_win(self) -> bool:
+        """Check for a win."""
+        on_switches = {
+            int(switch.name or "0") for switch in self.query(Switch) if switch.value
+        }
+        return on_switches == {1, 2, 3, 4, 6, 7, 8, 9}
+
+    def on_switch_changed(self, event: Switch.Changed) -> None:
+        """Called when a switch is toggled."""
+        # The switch that was pressed
+        switch_no = int(event.switch.name or "0")
+        # Also toggle corresponding switches
+        with self.prevent(Switch.Changed):
+            for toggle_no in TOGGLES[switch_no]:
+                self.query_one(f"#switch-{toggle_no}", Switch).toggle()
+        # Check the win
+        if self.check_win():
+            self.query_one("Screen").add_class("-win")
+            self.query_one(Timer).running = False
+
+    def on_key(self, event: events.Key) -> None:
+        """Maps switches to keys, so we can use the keyboard as well."""
+        if event.character and event.character.isdigit():
+            self.query_one(f"#switch-{event.character}", Switch).toggle()
+
+
+if __name__ == "__main__":
+    MerlinApp().run()