From 66ca6c0744cae6af0f3a3a39e199bb0e874a1e06 Mon Sep 17 00:00:00 2001
From: Edward Betts <edward@4angle.com>
Date: Thu, 18 Apr 2024 22:26:04 +0100
Subject: [PATCH] Get more exchange rates

---
 agenda/fx.py | 49 +++++++++++++++++++++++++++++++++++++++++++++++++
 update.py    |  5 ++++-
 2 files changed, 53 insertions(+), 1 deletion(-)

diff --git a/agenda/fx.py b/agenda/fx.py
index 1d48e49..b96d0c3 100644
--- a/agenda/fx.py
+++ b/agenda/fx.py
@@ -42,3 +42,52 @@ async def get_gbpusd(config: flask.config.Config) -> Decimal:
     data = json.loads(r.text, parse_float=Decimal)
 
     return typing.cast(Decimal, 1 / data["quotes"]["USDGBP"])
+
+
+def get_exchange_rates(config) -> dict[str, Decimal]:
+    """Get current values of exchange rates for a list of currencies against GBP."""
+    currencies = config.CURRENCIES
+    access_key = config.EXCHANGERATE_ACCESS_KEY
+    data_dir = config.DATA_DIR
+
+    now = datetime.now()
+    now_str = now.strftime("%Y-%m-%d_%H:%M")
+    fx_dir = os.path.join(data_dir, "fx")
+    os.makedirs(fx_dir, exist_ok=True)  # Ensure the directory exists
+
+    currency_string = ",".join(sorted(currencies))
+    file_suffix = f"{currency_string}_to_GBP.json"
+    existing_data = os.listdir(fx_dir)
+    existing_files = [f for f in existing_data if f.endswith(file_suffix)]
+
+    if existing_files:
+        recent_filename = max(existing_files)
+        recent = datetime.strptime(recent_filename[:16], "%Y-%m-%d_%H:%M")
+        delta = now - recent
+
+        if delta < timedelta(hours=6):
+            full_path = os.path.join(fx_dir, recent_filename)
+            with open(full_path) as file:
+                data = json.load(file, parse_float=Decimal)
+            return {
+                cur: Decimal(data["quotes"][f"GBP{cur}"])
+                for cur in currencies
+                if f"GBP{cur}" in data["quotes"]
+            }
+
+    url = "http://api.exchangerate.host/live"
+    params = {"currencies": currency_string, "source": "GBP", "access_key": access_key}
+
+    filename = f"{now_str}_{file_suffix}"
+    with httpx.Client() as client:
+        response = client.get(url, params=params)
+
+    with open(os.path.join(fx_dir, filename), "w") as file:
+        file.write(response.text)
+
+    data = json.loads(response.text, parse_float=Decimal)
+    return {
+        cur: Decimal(data["quotes"][f"GBP{cur}"])
+        for cur in currencies
+        if f"GBP{cur}" in data["quotes"]
+    }
diff --git a/update.py b/update.py
index 24c0976..c322387 100755
--- a/update.py
+++ b/update.py
@@ -12,13 +12,13 @@ from time import time
 
 import requests
 
+import agenda.fx
 import agenda.thespacedevs
 import agenda.types
 import agenda.uk_holiday
 import agenda.waste_schedule
 from agenda import gwr
 
-
 config = __import__("config.default", fromlist=[""])
 
 
@@ -133,6 +133,9 @@ def main() -> None:
         update_gwr_advance_ticket_date()
         update_gandi()
 
+    if hour % 12 == 0:
+        agenda.fx.get_exchange_rates(config)
+
     update_thespacedevs()