import sys
import json
import re
from datetime import datetime

timestamps = []

for line in sys.stdin:
    line = line.strip()
    if not line:
        continue
    
    # Remove invalid JSON explicit plus signs (e.g., :+0 -> :0)
    cleaned_line = re.sub(r':\s*\+(\d)', r':\1', line)
    
    try:
        data = json.loads(cleaned_line)
        if "Timestamp" in data:
            timestamps.append(int(data["Timestamp"]))
    except json.JSONDecodeError:
        continue

if not timestamps:
    print("No valid timestamps found.")
    sys.exit(1)

timestamps.sort()

# Calculate intervals
intervals_sec = [t2 - t1 for t1, t2 in zip(timestamps[:-1], timestamps[1:])]
intervals_min = [s / 60.0 for s in intervals_sec]

mean_min = sum(intervals_min) / len(intervals_min)
min_min = min(intervals_min)
max_min = max(intervals_min)

print("=== Recording Frequency Summary ===")
print(f"Total Records  : {len(timestamps)}")
print(f"Mean Interval  : {mean_min:.2f} minutes")
print(f"Min Interval   : {min_min:.2f} minutes")
print(f"Max Interval   : {max_min:.2f} minutes")

# Gap Detection (> 20 mins)
GAP_THRESHOLD_MIN = 20.0
print(f"\n=== Detected Gaps (> {GAP_THRESHOLD_MIN} mins) ===")
gaps_found = 0
for i, diff in enumerate(intervals_min):
    if diff > GAP_THRESHOLD_MIN:
        gaps_found += 1
        gap_time = datetime.utcfromtimestamp(timestamps[i+1]).strftime('%Y-%m-%d %H:%M:%S')
        missed = round(diff / 15) - 1
        print(f"Gap around {gap_time} UTC | Duration: {diff:.1f} mins (~{missed} missing readings)")

if gaps_found == 0:
    print("No gaps detected.")