Refactor: move code generation logic to src/codegen.rs

This lets sp-codegen.rs be only about the command line parsing etc.

1 files changed, 80 insertions, 5 deletions

diff --git a/src/codegen.rs b/src/codegen.rs
index bbe1ae7..fd398af 100644
--- a/src/codegen.rs
+++ b/src/codegen.rs
@@ -1,8 +1,83 @@
-use crate::Scenario;
+use crate::{Document, TemplateSpec};
+use std::collections::HashMap;
+use std::fs::File;
+use std::io::prelude::{Read, Write};
+use std::path::Path;
 
-/// Give a unique name for each scenario.
-pub fn name_scenarios(scens: &mut [Scenario]) {
-    for (i, scen) in scens.iter_mut().enumerate() {
-        scen.set_name(&format!("scenario_{}", i));
+use base64::encode;
+
+use tera::{Context, Tera, Value};
+
+use anyhow::Result;
+
+/// Return the requested template specification.
+pub fn template_spec(templates: &Path, doc: &Document) -> Result<TemplateSpec> {
+    let template = match doc.meta().template_name() {
+        Some(x) => &x,
+        None => "python",
+    };
+
+    let mut filename = templates.to_path_buf();
+    filename.push(Path::new(template));
+    filename.push(Path::new("template.yaml"));
+    Ok(TemplateSpec::from_file(&filename)?)
+}
+
+/// Generate a test program from a document, using a template spec.
+pub fn generate_test_program(
+    doc: &mut Document,
+    spec: &TemplateSpec,
+    filename: &Path,
+) -> Result<()> {
+    let context = context(doc)?;
+    let tera = tera(&spec)?;
+    let code = tera.render("template", &context).expect("render");
+    write(filename, &code)?;
+    Ok(())
+}
+
+fn context(doc: &mut Document) -> Result<Context> {
+    let mut context = Context::new();
+    context.insert("scenarios", &doc.matched_scenarios()?);
+    context.insert("files", doc.files());
+
+    let (funcs_filename, funcs) = match doc.meta().functions_filename() {
+        Some(filename) => (filename, cat(filename)?),
+        None => ("", "".to_string()),
+    };
+    context.insert("functions", &funcs);
+    context.insert("functions_filename", funcs_filename);
+
+    Ok(context)
+}
+
+fn tera(tmplspec: &TemplateSpec) -> Result<Tera> {
+    // Tera insists on a glob, but we want to load a specific template
+    // only, so we use a glob that doesn't match anything.
+    let mut tera = Tera::new(&"*notexist").expect("new");
+    tera.register_filter("base64", base64);
+    tera.add_template_file(tmplspec.template_filename(), Some("template"))?;
+    Ok(tera)
+}
+
+fn cat<P: AsRef<Path>>(filename: P) -> Result<String> {
+    let mut f = File::open(filename)?;
+    let mut buf = String::new();
+    f.read_to_string(&mut buf)?;
+    Ok(buf)
+}
+
+fn write(filename: &Path, content: &str) -> Result<()> {
+    let mut f: File = File::create(filename)?;
+    f.write_all(&content.as_bytes())?;
+    Ok(())
+}
+
+fn base64(v: &Value, _: &HashMap<String, Value>) -> tera::Result<Value> {
+    match v {
+        Value::String(s) => Ok(Value::String(encode(s))),
+        _ => Err(tera::Error::msg(
+            "can only base64 encode strings".to_string(),
+        )),
     }
 }