Add ProcessingJob type with source management and output path resolution

All 6 pipeline tests passing.

pixstrip-core/src/pipeline.rs

@@ -1 +1,83 @@
-// Processing pipeline
+use std::path::{Path, PathBuf};
+
+use serde::{Deserialize, Serialize};
+
+use crate::operations::*;
+use crate::types::{ImageFormat, ImageSource};
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct ProcessingJob {
+    pub input_dir: PathBuf,
+    pub output_dir: PathBuf,
+    #[serde(skip)]
+    pub sources: Vec<ImageSource>,
+    pub resize: Option<ResizeConfig>,
+    pub rotation: Option<Rotation>,
+    pub flip: Option<Flip>,
+    pub convert: Option<ConvertConfig>,
+    pub compress: Option<CompressConfig>,
+    pub metadata: Option<MetadataConfig>,
+    pub watermark: Option<WatermarkConfig>,
+    pub rename: Option<RenameConfig>,
+    pub preserve_directory_structure: bool,
+}
+
+impl ProcessingJob {
+    pub fn new(input_dir: impl AsRef<Path>, output_dir: impl AsRef<Path>) -> Self {
+        Self {
+            input_dir: input_dir.as_ref().to_path_buf(),
+            output_dir: output_dir.as_ref().to_path_buf(),
+            sources: Vec::new(),
+            resize: None,
+            rotation: None,
+            flip: None,
+            convert: None,
+            compress: None,
+            metadata: None,
+            watermark: None,
+            rename: None,
+            preserve_directory_structure: false,
+        }
+    }
+
+    pub fn add_source(&mut self, path: impl AsRef<Path>) {
+        self.sources.push(ImageSource::from_path(path));
+    }
+
+    pub fn operation_count(&self) -> usize {
+        let mut count = 0;
+        if self.resize.is_some() { count += 1; }
+        if self.rotation.is_some() { count += 1; }
+        if self.flip.is_some() { count += 1; }
+        if self.convert.is_some() { count += 1; }
+        if self.compress.is_some() { count += 1; }
+        if self.metadata.is_some() { count += 1; }
+        if self.watermark.is_some() { count += 1; }
+        if self.rename.is_some() { count += 1; }
+        count
+    }
+
+    pub fn output_path_for(
+        &self,
+        source: &ImageSource,
+        output_format: Option<ImageFormat>,
+    ) -> PathBuf {
+        let stem = source
+            .path
+            .file_stem()
+            .and_then(|s| s.to_str())
+            .unwrap_or("output");
+
+        let ext = output_format
+            .map(|f| f.extension())
+            .or_else(|| {
+                source
+                    .path
+                    .extension()
+                    .and_then(|e| e.to_str())
+            })
+            .unwrap_or("bin");
+
+        self.output_dir.join(format!("{}.{}", stem, ext))
+    }
+}