Extract pict-rs as library

src/config.rs

@@ -1,4 +1,5 @@
 use clap::Parser;
+use std::path::Path;
 
 mod commandline;
 mod defaults;
@@ -15,6 +16,34 @@ pub(crate) use primitives::{
     AudioCodec, Filesystem, ImageFormat, LogFormat, ObjectStorage, Store, VideoCodec,
 };
 
+pub(crate) fn configure_without_clap<P: AsRef<Path>, Q: AsRef<Path>>(
+    config_file: Option<P>,
+    save_to: Option<Q>,
+) -> color_eyre::Result<(Configuration, Operation)> {
+    let config = Config::builder().add_source(config::Config::try_from(&Defaults::default())?);
+
+    let config = if let Some(config_file) = config_file {
+        config.add_source(config::File::from(config_file.as_ref()))
+    } else {
+        config
+    };
+
+    let built = config
+        .add_source(config::Environment::with_prefix("PICTRS").separator("__"))
+        .build()?;
+
+    let operation = Operation::Run;
+
+    let config: Configuration = built.try_deserialize()?;
+
+    if let Some(save_to) = save_to {
+        let output = toml::to_string_pretty(&config)?;
+        std::fs::write(save_to, output)?;
+    }
+
+    Ok((config, operation))
+}
+
 pub(crate) fn configure() -> color_eyre::Result<(Configuration, Operation)> {
     let Output {
         config_format,