From eb9dca70a69e62393f60c5bd0058e76308f22593 Mon Sep 17 00:00:00 2001
From: Michael Zhang <mail@mzhang.io>
Date: Sat, 30 Dec 2023 04:39:55 -0500
Subject: [PATCH] refactor map generation into its own file

---
 Cargo.lock                                   |  1 +
 backend/Cargo.toml                           |  1 +
 backend/src/{generate.rs => generate/map.rs} | 56 +++++++++-----------
 backend/src/generate/mod.rs                  | 40 ++++++++++++++
 backend/src/state/game.rs                    |  2 +-
 5 files changed, 69 insertions(+), 31 deletions(-)
 rename backend/src/{generate.rs => generate/map.rs} (59%)
 create mode 100644 backend/src/generate/mod.rs

diff --git a/Cargo.lock b/Cargo.lock
index e90b9ac..167c461 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -266,6 +266,7 @@ dependencies = [
  "names",
  "petgraph 0.6.4",
  "prisma-client-rust",
+ "rand 0.8.5",
  "serde",
  "serde_json",
  "tokio",
diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index 0673470..deb04d0 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -16,3 +16,4 @@ tokio = { version = "1.35.1", features = ["full"] }
 serde_json = "1.0.108"
 petgraph = "0.6.4"
 names = "0.14.0"
+rand = "0.8.5"
diff --git a/backend/src/generate.rs b/backend/src/generate/map.rs
similarity index 59%
rename from backend/src/generate.rs
rename to backend/src/generate/map.rs
index 642c437..ca11915 100644
--- a/backend/src/generate.rs
+++ b/backend/src/generate/map.rs
@@ -1,22 +1,19 @@
 use std::{collections::HashMap, f64::consts::PI};
 
 use anyhow::Result;
-use chrono::Utc;
-use names::Generator as NameGenerator;
-use petgraph::{graph::UnGraph, graphmap::UnGraphMap};
+use petgraph::{
+  algo::min_spanning_tree, data::FromElements, graphmap::UnGraphMap,
+};
 use triangle::{triangulate, Point, TrianglulateOpts};
 
-use crate::{
-  prisma::PrismaClient,
-  state::{
-    EmpireCoreState, EmpireId, GameCoreState, StarSystemCoreState,
-    StarSystemId, UniverseId,
-  },
-};
+use crate::state::{StarSystemCoreState, StarSystemId};
 
-pub async fn generate_initial_game_state(
-  client: &PrismaClient,
-) -> Result<GameCoreState> {
+pub struct Map {
+  pub star_systems: HashMap<StarSystemId, StarSystemCoreState>,
+  pub hyperlanes: UnGraphMap<usize, ()>,
+}
+
+pub fn generate_map() -> Result<Map> {
   // Generate a new triangulation
   let result = {
     // Generate a circle of points
@@ -38,18 +35,6 @@ pub async fn generate_initial_game_state(
     )?
   };
 
-  // Generate a new universe ID
-  let universe = client.universe().create(json!({}), vec![]).exec().await?;
-
-  // Generate some empires
-  let mut empires = HashMap::new();
-  let name_generator = NameGenerator::default();
-  for (idx, name) in name_generator.take(10).enumerate() {
-    let id = EmpireId(idx as i32);
-    let empire = EmpireCoreState { id, name };
-    empires.insert(id, empire);
-  }
-
   // Format the star systems
   let mut star_systems = HashMap::new();
   for (idx, point) in result.point_list.into_iter().enumerate() {
@@ -69,11 +54,22 @@ pub async fn generate_initial_game_state(
     hyperlanes.add_edge(indexes[1], indexes[2], ());
   }
 
-  Ok(GameCoreState {
-    universe_id: UniverseId(universe.id),
-    current_instant: Utc::now(),
-    empires,
+  // Let's just drop some random % of hyperlanes
+  let min_hyperlanes =
+    UnGraphMap::from_elements(min_spanning_tree(&hyperlanes));
+  let final_hyperlanes = hyperlanes
+    .all_edges()
+    .filter(|edge| {
+      if min_hyperlanes.contains_edge(edge.0, edge.1) {
+        true
+      } else {
+        rand::random::<f64>() > 0.7
+      }
+    })
+    .collect();
+
+  Ok(Map {
     star_systems,
-    hyperlanes,
+    hyperlanes: final_hyperlanes,
   })
 }
diff --git a/backend/src/generate/mod.rs b/backend/src/generate/mod.rs
new file mode 100644
index 0000000..9756d53
--- /dev/null
+++ b/backend/src/generate/mod.rs
@@ -0,0 +1,40 @@
+mod map;
+
+use std::collections::HashMap;
+
+use anyhow::Result;
+use chrono::Utc;
+use names::Generator as NameGenerator;
+
+use crate::{
+  prisma::PrismaClient,
+  state::{EmpireCoreState, EmpireId, GameCoreState, UniverseId},
+};
+
+use self::map::generate_map;
+
+pub async fn generate_initial_game_state(
+  client: &PrismaClient,
+) -> Result<GameCoreState> {
+  // Generate a new universe ID
+  let universe = client.universe().create(json!({}), vec![]).exec().await?;
+
+  // Generate some empires
+  let mut empires = HashMap::new();
+  let name_generator = NameGenerator::default();
+  for (idx, name) in name_generator.take(10).enumerate() {
+    let id = EmpireId(idx as i32);
+    let empire = EmpireCoreState { id, name };
+    empires.insert(id, empire);
+  }
+
+  let map = generate_map()?;
+
+  Ok(GameCoreState {
+    universe_id: UniverseId(universe.id),
+    current_instant: Utc::now(),
+    empires,
+    star_systems: map.star_systems,
+    hyperlanes: map.hyperlanes,
+  })
+}
diff --git a/backend/src/state/game.rs b/backend/src/state/game.rs
index e225afb..ab3567a 100644
--- a/backend/src/state/game.rs
+++ b/backend/src/state/game.rs
@@ -2,7 +2,7 @@ use std::collections::HashMap;
 
 use anyhow::Result;
 use chrono::{DateTime, Utc};
-use petgraph::{graph::UnGraph, graphmap::UnGraphMap};
+use petgraph::graphmap::UnGraphMap;
 
 use crate::prisma::{empire, star_system, star_system_edges, PrismaClient};