From 2d0f2fb8651de1507f5221d74a2ca68819b83f3c Mon Sep 17 00:00:00 2001
From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Sat, 25 Feb 2023 17:46:00 +0100
Subject: [PATCH] main: iterate over regions of a Minecraft save dir

---
 src/main.rs | 80 +++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 68 insertions(+), 12 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 63711c1..c10cd4a 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,23 +1,42 @@
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
-use anyhow::Result;
+use anyhow::{Context, Result};
 use clap::Parser;
 
 use minedmap::{resource, world};
 
 #[derive(Debug, Parser)]
 struct Args {
-	/// Filename to dump
-	file: PathBuf,
+	/// Minecraft save directory
+	savedir: PathBuf,
 }
 
-fn main() -> Result<()> {
-	let args = Args::parse();
+/// Type with methods for processing the regions of a Minecraft save directory
+struct RegionProcessor {
+	block_types: resource::BlockTypeMap,
+}
 
-	let block_types = resource::block_types();
+impl RegionProcessor {
+	fn new() -> Self {
+		RegionProcessor {
+			block_types: resource::block_types(),
+		}
+	}
 
-	minedmap::io::region::from_file(args.file.as_path())?.foreach_chunk(
-		|coords, data: world::de::Chunk| {
+	/// Parses a filename in the format r.X.Z.mca into the contained X and Z values
+	fn parse_region_filename(path: &Path) -> Option<(i32, i32)> {
+		let file_name = path.file_name()?.to_str()?;
+		let parts: Vec<_> = file_name.split('.').collect();
+		let &["r", x, z, "mca"] = parts.as_slice() else {
+			return None;
+		};
+
+		Some((x.parse().ok()?, z.parse().ok()?))
+	}
+
+	/// Processes a single region file
+	fn process_region(&self, path: &Path, _x: i32, _z: i32) -> Result<()> {
+		minedmap::io::region::from_file(path)?.foreach_chunk(|coords, data: world::de::Chunk| {
 			let chunk = match world::chunk::Chunk::new(&data) {
 				Ok(chunk) => chunk,
 				Err(err) => {
@@ -26,10 +45,47 @@ fn main() -> Result<()> {
 				}
 			};
 
-			match world::layer::top_layer(&chunk, &block_types) {
+			match world::layer::top_layer(&chunk, &self.block_types) {
 				Ok(_) => {}
 				Err(err) => println!("{:?}", err),
 			}
-		},
-	)
+		})
+	}
+
+	/// Iterates over all region files of a Minecraft save directory
+	fn process_region_dir(&self, regiondir: &Path) -> Result<()> {
+		let read_dir = regiondir
+			.read_dir()
+			.with_context(|| format!("Failed to read directory {}", regiondir.display()))?;
+
+		for entry in read_dir.filter_map(|entry| entry.ok()).filter(|entry| {
+			// We are only interested in regular files
+			entry
+				.file_type()
+				.map(|file_type| file_type.is_file())
+				.unwrap_or_default()
+		}) {
+			let path = entry.path();
+			let Some((x, z)) = Self::parse_region_filename(&path) else {
+			continue;
+		};
+
+			if let Err(err) = self.process_region(&path, x, z) {
+				eprintln!("Failed to process region r.{}.{}.mca: {}", x, z, err);
+			}
+		}
+
+		Ok(())
+	}
+}
+
+fn main() -> Result<()> {
+	let args = Args::parse();
+
+	let regiondir: PathBuf = [&args.savedir, Path::new("region")].iter().collect();
+
+	let region_processor = RegionProcessor::new();
+	region_processor.process_region_dir(&regiondir)?;
+
+	Ok(())
 }