replace Player::profession with PlayerClass enum

Away with stringly typed stuff, we now have a proper way to save the
profession of a player without relying on a string. Theoretically, that
is better for memory consumption, as we now save only the identifier and
use fmt::Display and static strings, but that was not the main reason
for this change.

The main reason is that now we can programatically work with the
profession and elite spec, so that we can (for example) implement a
filter to filter players based on their class.

The word "class" has been chosen because it is a common synonym for the
profession/elite, and because this is neither a profession nor the elite
- it's a combination of both.

1 files changed, 141 insertions, 0 deletions

diff --git a/src/playerclass.rs b/src/playerclass.rs
new file mode 100644
index 0000000..77b9794
--- /dev/null
+++ b/src/playerclass.rs
@@ -0,0 +1,141 @@
+use std::{fmt, str::FromStr};
+
+use evtclib::{EliteSpec, Profession};
+
+use thiserror::Error;
+
+/// An enum containing either a profession or an elite spec.
+///
+/// This enum provides us with a variety of things:
+///
+/// Game mechanic wise, a Dragonhunter is also a Guardian, because Dragonhunter is only the elite
+/// specialization. However, when outputting that to the user, we usually only write Dragonhunter,
+/// and not Guardian, as that is implied. Same when filtering, when we filter for Guardian, we
+/// probably don't want any Dragonhunters.
+///
+/// So this enum unifies the handling between core specs and elite specs, and provides them with a
+/// convenient [`Display`][Display] implementation as well.
+#[derive(Debug, Clone, Copy, Hash, PartialEq, Eq)]
+pub enum PlayerClass {
+    Profession(Profession),
+    EliteSpec(EliteSpec),
+}
+
+#[derive(Debug, Clone, Hash, PartialEq, Eq, Error)]
+#[error("could not parse the class: {0}")]
+pub struct ParsePlayerClassError(String);
+
+impl From<Profession> for PlayerClass {
+    fn from(p: Profession) -> Self {
+        PlayerClass::Profession(p)
+    }
+}
+
+impl From<EliteSpec> for PlayerClass {
+    fn from(e: EliteSpec) -> Self {
+        PlayerClass::EliteSpec(e)
+    }
+}
+
+impl FromStr for PlayerClass {
+    type Err = ParsePlayerClassError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let err = ParsePlayerClassError(s.to_owned());
+        Profession::from_str(s)
+            .map(Into::into)
+            .map_err(|_| err.clone())
+            .or_else(|_| EliteSpec::from_str(s).map(Into::into).map_err(|_| err))
+    }
+}
+
+impl From<(Profession, Option<EliteSpec>)> for PlayerClass {
+    fn from((profession, elite_spec): (Profession, Option<EliteSpec>)) -> Self {
+        if let Some(spec) = elite_spec {
+            spec.into()
+        } else {
+            profession.into()
+        }
+    }
+}
+
+impl fmt::Display for PlayerClass {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use EliteSpec::*;
+        use Profession::*;
+
+        let name = match *self {
+            PlayerClass::EliteSpec(elite) => match elite {
+                Dragonhunter => "Dragonhunter",
+                Firebrand => "Firebrand",
+                Berserker => "Berserker",
+                Spellbreaker => "Spellbreaker",
+                Herald => "Herald",
+                Renegade => "Renegade",
+                Scrapper => "Scrapper",
+                Holosmith => "Holosmith",
+                Druid => "Druid",
+                Soulbeast => "Soulbeast",
+                Daredevil => "Daredevil",
+                Deadeye => "Deadeye",
+                Tempest => "Tempest",
+                Weaver => "Weaver",
+                Chronomancer => "Chronomancer",
+                Mirage => "Mirage",
+                Reaper => "Reaper",
+                Scourge => "Scourge",
+            },
+            PlayerClass::Profession(prof) => match prof {
+                Guardian => "Guardian",
+                Warrior => "Warrior",
+                Revenant => "Revenant",
+                Engineer => "Engineer",
+                Ranger => "Ranger",
+                Thief => "Thief",
+                Elementalist => "Elementalist",
+                Mesmer => "Mesmer",
+                Necromancer => "Necromancer",
+            },
+        };
+        write!(f, "{}", name)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_player_class_from() {
+        let tests: &[(Profession, Option<EliteSpec>, PlayerClass)] = &[
+            (
+                Profession::Guardian,
+                None,
+                PlayerClass::Profession(Profession::Guardian),
+            ),
+            (
+                Profession::Guardian,
+                Some(EliteSpec::Dragonhunter),
+                PlayerClass::EliteSpec(EliteSpec::Dragonhunter),
+            ),
+        ];
+
+        for (prof, elite_spec, expected) in tests {
+            assert_eq!(PlayerClass::from((*prof, *elite_spec)), *expected);
+        }
+    }
+
+    #[test]
+    fn test_parse_player_class() {
+        let tests: &[(&'static str, PlayerClass)] = &[
+            ("guardian", Profession::Guardian.into()),
+            ("dragonhunter", EliteSpec::Dragonhunter.into()),
+            ("warrior", Profession::Warrior.into()),
+            ("scourge", EliteSpec::Scourge.into()),
+        ];
+
+        for (input, expected) in tests {
+            assert_eq!(input.parse(), Ok(*expected));
+        }
+    }
+}