sqlc-gen-sqlx 0.2.0

use crate::error::Error;

/// Collects `TokenStream` fragments and formats them into a Rust source file
/// using `prettyplease`.
pub struct FileEmitter {
    sqlc_version: String,
    plugin_version: String,
    items: Vec<proc_macro2::TokenStream>,
}

impl FileEmitter {
    pub fn new(sqlc_version: &str, plugin_version: &str) -> Self {
        Self {
            sqlc_version: sqlc_version.to_string(),
            plugin_version: plugin_version.to_string(),
            items: Vec::new(),
        }
    }

    /// Append a token stream fragment (a struct, impl block, fn, const, etc.).
    pub fn push(&mut self, tokens: proc_macro2::TokenStream) {
        self.items.push(tokens);
    }

    /// Render all items into a formatted Rust source string.
    pub fn finish(self) -> Result<String, Error> {
        use quote::quote;

        let items = &self.items;
        let combined = quote! { #(#items)* };

        let file: syn::File = syn::parse2(combined)
            .map_err(|e| Error::Codegen(format!("token stream parse failed: {e}")))?;

        let formatted = prettyplease::unparse(&file);

        // Pre-wrapped to satisfy `cargo fmt --check` at the default 100-col
        // max_width — the single-line form exceeds the limit and rustfmt
        // rewrites it.
        let header = format!(
            "// Code generated by sqlc-gen-sqlx v{}. DO NOT EDIT.\n\
             // sqlc version: {}\n\n\
             #![allow(\n    dead_code,\n    reason = \"generated queries may expose items a caller does not use\"\n)]\n\n",
            self.plugin_version, self.sqlc_version,
        );

        Ok(format!("{header}{formatted}"))
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn emits_valid_rust() {
        let mut e = FileEmitter::new("0.0.0-test", "sqlc-test");
        e.push(quote::quote! { pub struct Foo { pub x: i32 } });
        let code = e.finish().unwrap();
        assert!(code.contains("pub struct Foo"));
        assert!(code.contains("pub x: i32"));
        // Header comment present
        assert!(code.contains("DO NOT EDIT"));
        assert!(code.contains("sqlc-gen-sqlx vsqlc-test"));
        assert!(code.contains("sqlc version: 0.0.0-test"));
        assert!(code.contains(
            "#![allow(\n    dead_code,\n    reason = \"generated queries may expose items a caller does not use\"\n)]"
        ));
    }

    #[test]
    fn emits_empty_file_with_header() {
        let e = FileEmitter::new("1.0.0", "sqlc");
        let code = e.finish().unwrap();
        assert!(code.contains("DO NOT EDIT"));
    }
}