#!/usr/bin/env python3
"""Task 5 (user decision 2026-10-21): no pattern-station data exists. Create a
PLACEHOLDER pattern table at 2 m segments over the modelled range 4+745..5+480,
cycling the six pattern names. Every row is marked '임의 배정 (placeholder)'.
The table is an editable CSV: replace the 'pattern' column later and rebuild.
Output: data/pattern_zones_placeholder.csv (created only if absent; never overwritten)."""
import csv
import os
import sys

ROOT = sys.argv[1]
OUT = f"{ROOT}/data/pattern_zones_placeholder.csv"
PATTERNS = ["NP-4AD-1-D-2", "NP-4BD-1-D-2", "NP-5AE-1-WL-4", "NP-5BE-1-WL-4", "NP-6A", "NP-6B"]
S0, S1, SEG = 4745, 5480, 2
if not os.path.exists(OUT):
    with open(OUT, "w", newline="", encoding="utf-8") as fh:
        w = csv.writer(fh)
        w.writerow(["seg_from", "seg_to", "pattern", "status"])
        for k, s in enumerate(range(S0, S1, SEG)):
            w.writerow([s, min(s + SEG, S1), PATTERNS[k % len(PATTERNS)], "임의 배정 (placeholder, 실제 구간 아님)"])
print("pattern table:", OUT)