existential types in rust are weird

… lots and lots of traits …

3 files changed, 219 insertions, 7 deletions

diff --git a/src/iceportal.rs b/src/onboard/iceportal.rs
index 3cb5e6f..04ec291 100644
--- a/src/iceportal.rs
+++ b/src/onboard/iceportal.rs
@@ -1,8 +1,14 @@
+/// implementation of traits to query the iceportal.de
+/// (available in high speed trains in DE)
 use chrono::{DateTime, Utc};
 use serde::Deserialize;
 use serde_json::Value;
 
-use crate::{serde::*, travelynx::TrainRef, types::IsStation};
+use crate::onboard;
+use crate::onboard::{OnBoardAPI, OnBoardInfo};
+use crate::{serde::*, traits::*, travelynx::TrainRef};
+
+pub struct Iceportal {}
 
 #[derive(Deserialize, Debug)]
 #[serde(rename_all = "camelCase")]
@@ -72,8 +78,8 @@ impl IsStation for Stop {
   }
 }
 
-impl TripInfo {
-  pub fn guess_last_station(&self) -> Option<String> {
+impl OnBoardInfo for TripInfo {
+  fn guess_last_station(&self) -> Option<&dyn IsStation> {
     let current_pos = self.trip.actual_position;
     self
       .trip
@@ -83,17 +89,38 @@ impl TripInfo {
       .map(|stop| (stop.info.distance_from_start, stop))
       .filter(|(dist, _)| dist <= &current_pos)
       .next()
-      .map(|(_, stop)| stop.station.name.clone())
+      .map(|(_, stop)| stop as &dyn IsStation)
   }
 
-  pub fn get_train_ref(&self) -> TrainRef {
+  fn get_train_ref(&self) -> TrainRef {
     TrainRef {
       _type: self.trip.train_type.clone(),
       no: self.trip.vzn.clone()
     }
   }
 
-  pub fn trip(&self) -> crate::types::Trip<'_, Stop> {
-    crate::types::Trip(&self.trip.stops)
+  fn stops<'a>(
+    &'a self
+  ) -> Box<dyn std::iter::Iterator<Item = &'a dyn IsStation> + 'a> {
+    Box::new(self.trip.stops.iter().map(|s| s as &dyn IsStation))
+  }
+}
+
+impl std::fmt::Display for Stop {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    write!(f, "{}", self.station.name)
+  }
+}
+
+impl OnBoardAPI for Iceportal {
+  fn apiurl(&self) -> &'static str {
+    "https://iceportal.de/api1/rs/tripInfo/trip"
+  }
+
+  fn request(
+    &self,
+    debug: bool
+  ) -> Result<Box<dyn OnBoardInfo>, serde_json::Error> {
+    onboard::request::<_, TripInfo>(self, debug)
   }
 }
diff --git a/src/onboard/mod.rs b/src/onboard/mod.rs
new file mode 100644
index 0000000..56bd144
--- /dev/null
+++ b/src/onboard/mod.rs
@@ -0,0 +1,76 @@
+use crate::traits::IsStation;
+use crate::travelynx::TrainRef;
+use serde::de::DeserializeOwned;
+
+pub mod iceportal;
+pub mod zugportal;
+
+pub fn choose_api(name: &str) -> &dyn OnBoardAPI {
+  match name {
+    "iceportal" => &iceportal::Iceportal {} as &dyn OnBoardAPI,
+    "zugportal" => &zugportal::Zugportal {} as &dyn OnBoardAPI,
+    _ => panic!("no such API known")
+  }
+}
+
+pub trait OnBoardAPI {
+  fn apiurl(&self) -> &'static str;
+
+  fn request(
+    &self,
+    debug: bool
+  ) -> Result<Box<dyn OnBoardInfo>, serde_json::Error>;
+}
+
+pub fn request<Api, I>(
+  api: &Api,
+  debug: bool
+) -> Result<Box<dyn OnBoardInfo>, serde_json::Error>
+where
+  Api: OnBoardAPI,
+  I: OnBoardInfo + DeserializeOwned + 'static
+{
+  let url: &'static str = api.apiurl();
+  match get_request::<I>(url) {
+    Ok(resp) => Ok(Box::new(resp)),
+    Err((err, resp)) => {
+      if debug {
+        eprintln!("{:?}\n\nError was:{:?}", resp, err);
+      }
+      Err(err)
+    }
+  }
+}
+
+pub trait OnBoardInfo {
+  fn guess_last_station(&self) -> Option<&dyn IsStation>;
+
+  fn get_train_ref(&self) -> TrainRef;
+
+  fn stops<'a>(
+    &'a self
+  ) -> Box<dyn std::iter::Iterator<Item = &'a dyn IsStation> + 'a>;
+}
+
+fn get_request<R>(uri: &str) -> Result<R, (serde_json::Error, String)>
+where
+  R: serde::de::DeserializeOwned
+{
+  let resp: String = ureq::get(uri)
+    .call()
+    .unwrap_or_else(|err| exit_err(&err.to_string(), "get request failed"))
+    .into_string()
+    .unwrap_or_else(|err| {
+      exit_err(&err.to_string(), "get request response failed")
+    });
+
+  match serde_json::from_str::<R>(&resp) {
+    Ok(obj) => Ok(obj),
+    Err(err) => Err((err, resp))
+  }
+}
+
+fn exit_err(msg: &str, scope: &str) -> ! {
+  eprintln!("{}: {}", scope, msg);
+  std::process::exit(1)
+}
diff --git a/src/onboard/zugportal.rs b/src/onboard/zugportal.rs
new file mode 100644
index 0000000..0ad6cfd
--- /dev/null
+++ b/src/onboard/zugportal.rs
@@ -0,0 +1,109 @@
+/// implementation of traits to query zugportal.de
+/// (available at least in the Munich S-Bahn, maybe other trains)
+use chrono::{DateTime, Utc};
+use serde::Deserialize;
+
+use crate::onboard;
+use crate::onboard::{OnBoardAPI, OnBoardInfo};
+use crate::{traits::*, travelynx::TrainRef};
+
+pub struct Zugportal {}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct Journey {
+  name: String, // the line's name, e.g. S 8
+  no: i64,
+  stops: Vec<Stop>
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+pub struct Stop {
+  station: Station,
+  status: String, // one of "Normal", ...?
+  track: Track,
+  messages: Vec<String>,
+  arrival_time: Option<DepartureTime>,
+  departure_time: Option<DepartureTime>
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+struct Station {
+  eva_no: String,
+  name: String
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+struct Track {
+  target: String,
+  prediction: String
+}
+
+#[derive(Deserialize, Debug)]
+#[serde(rename_all = "camelCase")]
+struct DepartureTime {
+  target: DateTime<Utc>,
+  predicted: DateTime<Utc>,
+  time_type: String, // one of REAL, PREVIEW, ..?
+  diff: i64          // diff in minutes?
+                     // NOTE: also sends predictedTimeInMs and targetTimeInMs; these might be unix times
+}
+
+impl IsStation for Stop {
+  fn name(&self) -> &str {
+    &self.station.name
+  }
+
+  fn scheduled_arrival(&self) -> Option<&chrono::DateTime<Utc>> {
+    self.arrival_time.as_ref().map(|t| &t.target)
+  }
+
+  fn real_arrival(&self) -> Option<&chrono::DateTime<Utc>> {
+    self.arrival_time.as_ref().map(|t| &t.predicted)
+  }
+
+  fn ds100(&self) -> &str {
+    "??"
+  }
+}
+
+impl std::fmt::Display for Stop {
+  fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+    write!(f, "{}", self.station.name)
+  }
+}
+
+impl OnBoardInfo for Journey {
+  fn guess_last_station(&self) -> Option<&dyn IsStation> {
+    todo!()
+  }
+
+  fn get_train_ref(&self) -> TrainRef {
+    TrainRef {
+      _type: self.name.clone(),
+      no: self.no.to_string().clone()
+    }
+  }
+
+  fn stops<'a>(
+    &'a self
+  ) -> Box<dyn std::iter::Iterator<Item = &'a dyn IsStation> + 'a> {
+    Box::new(self.stops.iter().map(|s| s as &dyn IsStation))
+  }
+}
+
+impl OnBoardAPI for Zugportal {
+  fn apiurl(&self) -> &'static str {
+    "https://zugportal.de/prd/zupo-travel-information/api/public/ri/journey"
+  }
+
+  fn request(
+    &self,
+    debug: bool
+  ) -> Result<Box<dyn OnBoardInfo>, serde_json::Error> {
+    onboard::request::<_, Journey>(self, debug)
+  }
+}