chore: refactor ahead of supporting more conversion types

src/formats/mod.rs

@@ -0,0 +1,49 @@
+use std::ffi::OsStr;
+use std::path::Path;
+
+use anyhow::Result;
+
+use crate::model::Document;
+
+pub mod cbz;
+pub mod pdf;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum FormatId {
+    Cbz,
+    Pdf,
+}
+
+impl FormatId {
+    #[allow(dead_code)]
+    pub fn can_read(self) -> bool {
+        match self {
+            FormatId::Cbz => true,
+            FormatId::Pdf => false, // planned but not implemented yet
+        }
+    }
+
+    #[allow(dead_code)]
+    pub fn can_write(self) -> bool {
+        match self {
+            FormatId::Pdf => true,
+            FormatId::Cbz => false, // planned but not implemented yet
+        }
+    }
+
+    pub fn detect_from_path(path: &Path) -> Option<FormatId> {
+        match path.extension().and_then(OsStr::to_str) {
+            Some("cbz") => Some(FormatId::Cbz),
+            Some("pdf") => Some(FormatId::Pdf),
+            _ => None,
+        }
+    }
+}
+
+pub trait FormatReader: Send + Sync {
+    fn read(&self, input: &Path) -> Result<Document>;
+}
+
+pub trait FormatWriter: Send + Sync {
+    fn write(&self, doc: &Document, output: &Path) -> Result<()>;
+}