from machine import Pin
import time

# ---------------- Hardware ----------------
led_red = Pin(14, Pin.OUT)
led_amber = Pin(13, Pin.OUT)
led_green = Pin(12, Pin.OUT)

# Button on GPIO15, use internal pull-up: not pressed = 1, pressed = 0
button = Pin(15, Pin.IN, Pin.PULL_UP)

# ---------------- Helpers ----------------
def all_off():
    led_red.value(0)
    led_amber.value(0)
    led_green.value(0)

def apply_step(pattern, step_idx):
    r, y, g = pattern[step_idx]
    led_red.value(r)
    led_amber.value(y)
    led_green.value(g)
    return r, y, g

def print_status(mode_fast, step_idx, r, y, g, reason="tick"):
    mode_txt = "FAST" if mode_fast else "SLOW"
    print("[{}] mode={}, step={}, LEDs=(R:{} Y:{} G:{})".format(
        reason, mode_txt, step_idx, r, y, g
    ))

# ---------------- Patterns & Timings ----------------
pattern_slow = [
    (0, 0, 1),  # Green
    (0, 1, 0),  # Yellow
    (1, 0, 0),  # Red
]

pattern_fast = [
    (1, 0, 0),  # Red
    (0, 1, 0),  # Yellow
    (0, 0, 1),  # Green
]

STEP_MS_SLOW = 1200
STEP_MS_FAST = 500

# ---------------- State ----------------
mode_fast = False          # False = slow pattern, True = fast pattern
step_idx = 0               # current index in pattern
last_step_ms = time.ticks_ms()

# Button debounce and edge detection
last_btn = 1               # last read value (1=released due to pull-up)
last_press_ms = 0
DEBOUNCE_MS = 120

# Start clean and show initial state
all_off()
active_pattern = pattern_fast if mode_fast else pattern_slow
r, y, g = apply_step(active_pattern, step_idx)
print_status(mode_fast, step_idx, r, y, g, reason="start")

while True:
    # ---- Button edge detection with debounce (falling edge: 1 -> 0) ----
    curr = button.value()
    if last_btn == 1 and curr == 0:
        now = time.ticks_ms()
        if time.ticks_diff(now, last_press_ms) > DEBOUNCE_MS:
            # Toggle mode on each press
            mode_fast = not mode_fast
            last_press_ms = now

            # Reset to the beginning of the new pattern and APPLY IMMEDIATELY
            step_idx = 0
            active_pattern = pattern_fast if mode_fast else pattern_slow
            r, y, g = apply_step(active_pattern, step_idx)

            print_status(mode_fast, step_idx, r, y, g, reason="button-pressed")

            # Update step timer so the next step waits a full interval
            last_step_ms = now
    last_btn = curr

    # ---- Choose active pattern and step duration ----
    if mode_fast:
        active_pattern = pattern_fast
        step_ms = STEP_MS_FAST
    else:
        active_pattern = pattern_slow
        step_ms = STEP_MS_SLOW

    # ---- Advance pattern based on time (non-blocking) ----
    now = time.ticks_ms()
    if time.ticks_diff(now, last_step_ms) >= step_ms:
        # Move to next step
        step_idx = (step_idx + 1) % len(active_pattern)
        r, y, g = apply_step(active_pattern, step_idx)
        print_status(mode_fast, step_idx, r, y, g, reason="tick")
        last_step_ms = now

    # Tiny idle delay (keeps CPU cool, doesn’t affect timing)
    time.sleep_ms(2)