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|
use rand::seq::SliceRandom;
use rand::Rng;
use serde::de::MapAccess;
use serde::de::SeqAccess;
use serde::de::Visitor;
use std::collections::HashMap;
use std::fmt;
use std::marker::PhantomData;
#[derive(Deserialize, Debug, PartialEq, Eq)]
#[serde(untagged)]
enum Message<'a> {
Single(&'a str),
Choice(Vec<&'a str>),
}
impl<'a> Message<'a> {
fn resolve<R: Rng + ?Sized>(&self, rng: &mut R) -> Option<&'a str> {
use Message::*;
match self {
Single(msg) => Some(*msg),
Choice(msgs) => msgs.choose(rng).map(|msg| *msg),
}
}
}
#[derive(Debug, PartialEq, Eq)]
enum NestedMap<'a> {
Direct(Message<'a>),
Nested(HashMap<&'a str, NestedMap<'a>>),
}
impl<'a> NestedMap<'a> {
fn lookup(&'a self, path: &str) -> Option<&'a Message<'a>> {
use NestedMap::*;
let leaf =
path.split(".")
.fold(Some(self), |current, key| match current {
Some(Nested(m)) => m.get(key),
_ => None,
});
match leaf {
Some(Direct(msg)) => Some(msg),
_ => None,
}
}
}
struct NestedMapVisitor<'a> {
marker: PhantomData<fn() -> NestedMap<'a>>,
}
impl<'a> NestedMapVisitor<'a> {
fn new() -> Self {
NestedMapVisitor {
marker: PhantomData,
}
}
}
impl<'de> Visitor<'de> for NestedMapVisitor<'de> {
type Value = NestedMap<'de>;
fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
formatter.write_str(
"A message, a list of messages, or a nested map of messages",
)
}
fn visit_borrowed_str<E>(self, v: &'de str) -> Result<Self::Value, E> {
Ok(NestedMap::Direct(Message::Single(v)))
}
fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
where
A: SeqAccess<'de>,
{
let mut choices = Vec::with_capacity(seq.size_hint().unwrap_or(0));
while let Some(choice) = seq.next_element()? {
choices.push(choice);
}
Ok(NestedMap::Direct(Message::Choice(choices)))
}
fn visit_map<A>(self, mut map: A) -> Result<Self::Value, A::Error>
where
A: MapAccess<'de>,
{
let mut nested = HashMap::with_capacity(map.size_hint().unwrap_or(0));
while let Some((k, v)) = map.next_entry()? {
nested.insert(k, v);
}
Ok(NestedMap::Nested(nested))
}
}
impl<'de> serde::Deserialize<'de> for NestedMap<'de> {
fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
where
D: serde::Deserializer<'de>,
{
deserializer.deserialize_any(NestedMapVisitor::new())
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_deserialize_nested_map() {
let src = r#"
[global]
hello = "Hello World!"
[foo.bar]
single = "Single"
choice = ["Say this", "Or this"]
"#;
let result = toml::from_str(src);
assert_eq!(
result,
Ok(NestedMap::Nested(hashmap! {
"global" => NestedMap::Nested(hashmap!{
"hello" => NestedMap::Direct(Message::Single("Hello World!")),
}),
"foo" => NestedMap::Nested(hashmap!{
"bar" => NestedMap::Nested(hashmap!{
"single" => NestedMap::Direct(Message::Single("Single")),
"choice" => NestedMap::Direct(Message::Choice(
vec!["Say this", "Or this"]
))
})
})
}))
)
}
#[test]
fn test_lookup() {
let map: NestedMap<'static> = toml::from_str(
r#"
[global]
hello = "Hello World!"
[foo.bar]
single = "Single"
choice = ["Say this", "Or this"]
"#,
)
.unwrap();
assert_eq!(
map.lookup("global.hello"),
Some(&Message::Single("Hello World!"))
);
assert_eq!(
map.lookup("foo.bar.single"),
Some(&Message::Single("Single"))
);
assert_eq!(
map.lookup("foo.bar.choice"),
Some(&Message::Choice(vec!["Say this", "Or this"]))
);
}
}
static MESSAGES_RAW: &'static str = include_str!("messages.toml");
lazy_static! {
static ref MESSAGES: NestedMap<'static> =
toml::from_str(MESSAGES_RAW).unwrap();
}
/// Look up a game message based on the given (dot-separated) name, with the
/// given random generator used to select from choice-based messages
pub fn message<R: Rng + ?Sized>(name: &str, rng: &mut R) -> &'static str {
use Message::*;
MESSAGES
.lookup(name)
.and_then(|msg| msg.resolve(rng))
.unwrap_or_else(|| {
error!("Message not found: {}", name);
"Message not found"
})
}
|
