From 945d028c1367ebde4abeed6d920af7614e585bab Mon Sep 17 00:00:00 2001
From: Edward Betts <edward@4angle.com>
Date: Wed, 1 Apr 2026 12:17:50 +0100
Subject: [PATCH] Generate Eurostar timetable URLs from station IDs

---
 app.py                         |  2 +-
 scraper/eurostar.py            | 46 ++++++++++++++++++----------------
 tests/test_eurostar_scraper.py | 16 +++++++++++-
 3 files changed, 40 insertions(+), 24 deletions(-)

diff --git a/app.py b/app.py
index 6e9e6fd..1a61c9c 100644
--- a/app.py
+++ b/app.py
@@ -115,7 +115,7 @@ def results(slug, travel_date):
     next_date = (dt + timedelta(days=1)).isoformat()
     travel_date_display = dt.strftime('%A %-d %B %Y')
 
-    eurostar_url = eurostar_scraper.ROUTE_URLS[destination] + f"?date={travel_date}"
+    eurostar_url = eurostar_scraper.timetable_url(destination) + f"?date={travel_date}"
     rtt_url = RTT_PADDINGTON_URL.format(date=travel_date)
 
     return render_template(
diff --git a/scraper/eurostar.py b/scraper/eurostar.py
index 4307835..7e9f3e7 100644
--- a/scraper/eurostar.py
+++ b/scraper/eurostar.py
@@ -22,30 +22,32 @@ DEFAULT_UA = (
     "(KHTML, like Gecko) Chrome/122.0.0.0 Safari/537.36"
 )
 
-ROUTE_URLS = {
-    'Paris Gare du Nord': (
-        'https://www.eurostar.com/uk-en/travel-info/timetable/'
-        '7015400/8727100/london-st-pancras-intl/paris-gare-du-nord'
-    ),
-    'Brussels Midi': (
-        'https://www.eurostar.com/uk-en/travel-info/timetable/'
-        '7015400/8814001/london-st-pancras-intl/brussels-midi'
-    ),
-    'Lille Europe': (
-        'https://www.eurostar.com/uk-en/travel-info/timetable/'
-        '7015400/8722326/london-st-pancras-intl/lille-europe'
-    ),
-    'Amsterdam Centraal': (
-        'https://www.eurostar.com/uk-en/travel-info/timetable/'
-        '7015400/8400058/london-st-pancras-intl/amsterdam-centraal'
-    ),
-    'Rotterdam Centraal': (
-        'https://www.eurostar.com/uk-en/travel-info/timetable/'
-        '7015400/8400530/london-st-pancras-intl/rotterdam-centraal'
-    ),
+ORIGIN_STATION_ID = '7015400'
+ORIGIN_STATION_SLUG = 'london-st-pancras-intl'
+TIMETABLE_BASE_URL = 'https://www.eurostar.com/uk-en/travel-info/timetable'
+
+DESTINATION_STATION_IDS = {
+    'Paris Gare du Nord': '8727100',
+    'Brussels Midi': '8814001',
+    'Lille Europe': '8722326',
+    'Amsterdam Centraal': '8400058',
+    'Rotterdam Centraal': '8400530',
 }
 
 
+def _slugify_station_name(name: str) -> str:
+    return re.sub(r'[^a-z0-9]+', '-', name.lower()).strip('-')
+
+
+def timetable_url(destination: str) -> str:
+    dest_id = DESTINATION_STATION_IDS[destination]
+    dest_slug = _slugify_station_name(destination)
+    return (
+        f'{TIMETABLE_BASE_URL}/{ORIGIN_STATION_ID}/{dest_id}/'
+        f'{ORIGIN_STATION_SLUG}/{dest_slug}'
+    )
+
+
 def _hhmm(dt_str: str | None) -> str | None:
     """'2026-03-30 09:34:00' → '09:34'"""
     if not dt_str:
@@ -78,7 +80,7 @@ def _parse(html: str, destination: str) -> list[dict]:
 
 def fetch(destination: str, travel_date: str,
           user_agent: str = DEFAULT_UA) -> list[dict]:
-    url = ROUTE_URLS[destination]
+    url = timetable_url(destination)
     headers = {
         'User-Agent': user_agent,
         'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
diff --git a/tests/test_eurostar_scraper.py b/tests/test_eurostar_scraper.py
index ff2d4b1..137cf71 100644
--- a/tests/test_eurostar_scraper.py
+++ b/tests/test_eurostar_scraper.py
@@ -1,6 +1,6 @@
 import json
 import pytest
-from scraper.eurostar import _hhmm, _parse
+from scraper.eurostar import _hhmm, _parse, timetable_url
 
 
 # ---------------------------------------------------------------------------
@@ -80,3 +80,17 @@ def test_parse_no_next_data_returns_empty():
 def test_parse_empty_departures():
     html = _make_next_data([])
     assert _parse(html, 'Paris Gare du Nord') == []
+
+
+def test_timetable_url_uses_station_id_table():
+    assert timetable_url('Paris Gare du Nord') == (
+        'https://www.eurostar.com/uk-en/travel-info/timetable/'
+        '7015400/8727100/london-st-pancras-intl/paris-gare-du-nord'
+    )
+
+
+def test_timetable_url_slugifies_destination_name():
+    assert timetable_url('Rotterdam Centraal') == (
+        'https://www.eurostar.com/uk-en/travel-info/timetable/'
+        '7015400/8400530/london-st-pancras-intl/rotterdam-centraal'
+    )