Allow setting the center of the map

default.nix

@@ -1,15 +1,26 @@
 { pkgs, lib, config, ... }:
 {
   options = {
-    scripts.output = lib.mkOption {
+    scripts = {
+      output = lib.mkOption {
         type = lib.types.package;
       };
 
+      geocode = lib.mkOption {
+        type = lib.types.package;
+      };
+    };
+
     map = {
       zoom = lib.mkOption {
         type = lib.types.nullOr lib.types.int;
         default = 2;
       };
+
+      center = lib.mkOption {
+        type = lib.types.nullOr lib.types.str;
+        default = "Switzerland";
+      };
     };
 
     requestParams = lib.mkOption {
@@ -18,7 +29,8 @@
   };
 
   config = {
-    scripts.output = pkgs.writeShellApplication {
+    scripts = {
+      output = pkgs.writeShellApplication {
         name = "map";
 
         runtimeInputs = with pkgs; [
@@ -31,11 +43,27 @@
         '';
       };
 
+      geocode = pkgs.writeShellApplication {
+        name = "geocode";
+
+        runtimeInputs = with pkgs; [
+          curl
+          jq
+        ];
+
+        text = ''exec ${./geocode} "$@"'';
+      };
+    };
+
     requestParams = [
       "size=640x300"
       "scale=2"
       (lib.mkIf (config.map.zoom != null)
         "zoom=${toString config.map.zoom}")
+      (lib.mkIf (config.map.center != null)
+        "center=\"${config.scripts.geocode}/bin/geocode ${
+          lib.escapeShellArg config.map.center
+        }\"")
     ];
   };
 }

geocode

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+cachedir=~/.cache/google-api/geocode
+mkdir -p "$cachedir"
+hash=$(echo "$1" | sha256sum - | cut -d' ' -f1)
+cachefile="$cachedir/$hash"
+
+if [[ ! -f "$cachefile" ]]; then
+
+  keyFile=${XDG_DATA_HOME:-~/.local/share}/google-api/key
+
+  if [[ ! -f "$keyFile" ]]; then
+    mkdir -p "$(basename "$keyFile")"
+    echo "No Google API key found in $keyFile" >&2
+    echo "For getting one, see https://developers.google.com/maps/documentation/geocoding/overview#before-you-begin" >&2
+    exit 1
+  fi
+
+  key=$(cat "$keyFile")
+
+
+  tmp=$(mktemp -d)
+  trap 'rm -rf "$tmp"' exit
+
+  output=$tmp/output
+
+  curlArgs=(
+    https://maps.googleapis.com/maps/api/geocode/json
+    --silent --show-error --get --output "$output" --write-out '%{http_code}'
+    --data-urlencode address="$1"
+  )
+
+  #echo curl ''${curlArgs[@]@Q} >&2
+
+  curlArgs+=(--data-urlencode key="$key")
+
+  if status=$(curl "${curlArgs[@]}"); then
+    if [[ "$status" == 200 ]]; then
+      jq -r '.results[0].geometry.location as $loc | "\($loc | .lat),\($loc | .lng)"' "$output" > "$cachefile"
+    else
+      echo "API returned non-200 HTTP status code $status, output is" >&2
+      cat "$output" >&2
+      exit 1
+    fi
+  else
+    code=$?
+    echo "curl exited with code $code" >&2
+    exit 1
+  fi
+fi
+
+cat "$cachefile"