scythe-codegen 0.11.0

Polyglot code generation backends for scythe
Documentation
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use scythe_backend::manifest::BackendManifest;
use scythe_backend::naming::{
    enum_type_name, enum_variant_name, fn_name, row_struct_name, to_camel_case, to_pascal_case,
};
use scythe_backend::types::resolve_type;
use std::fmt::Write;

use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
use scythe_core::errors::{ErrorCode, ScytheError};
use scythe_core::parser::QueryCommand;

use crate::backend_trait::GroupedQueryFn;
use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
use crate::backends::typescript_common::{
    TsRowType, generate_grouped_interface_structs, generate_ts_grouped_fold_body, generate_zod_enum,
    generate_zod_grouped_structs, generate_zod_row_struct,
};
use crate::singularize;

const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/typescript-pg.toml");
const DEFAULT_MANIFEST_REDSHIFT: &str = include_str!("../../manifests/typescript-pg.redshift.toml");

pub struct TypescriptPgBackend {
    manifest: BackendManifest,
    row_type: TsRowType,
}

impl TypescriptPgBackend {
    pub fn new(engine: &str) -> Result<Self, ScytheError> {
        let default_toml = match engine {
            "postgresql" | "postgres" | "pg" => DEFAULT_MANIFEST_TOML,
            "redshift" => DEFAULT_MANIFEST_REDSHIFT,
            _ => {
                return Err(ScytheError::new(
                    ErrorCode::InternalError,
                    format!(
                        "typescript-pg only supports PostgreSQL/Redshift, got engine '{}'",
                        engine
                    ),
                ));
            }
        };
        let manifest = super::load_or_default_manifest("backends/typescript-pg/manifest.toml", default_toml)?;
        Ok(Self {
            manifest,
            row_type: TsRowType::default(),
        })
    }
}

impl CodegenBackend for TypescriptPgBackend {
    fn name(&self) -> &str {
        "typescript-pg"
    }

    fn manifest(&self) -> &scythe_backend::manifest::BackendManifest {
        &self.manifest
    }

    fn supported_engines(&self) -> &[&str] {
        &["postgresql", "redshift"]
    }

    fn file_header(&self) -> String {
        let mut header =
            "/** Auto-generated by scythe. Do not edit. */\n\nimport type { PoolClient } from \"pg\";\n".to_string();
        if self.row_type == TsRowType::Zod {
            header.push_str("import { z } from \"zod\";\n");
        }
        header
    }

    fn generate_row_struct(&self, query_name: &str, columns: &[ResolvedColumn]) -> Result<String, ScytheError> {
        let struct_name = row_struct_name(query_name, &self.manifest.naming);
        if self.row_type == TsRowType::Zod {
            return Ok(generate_zod_row_struct(&struct_name, query_name, columns));
        }
        let mut out = String::new();
        let _ = writeln!(out, "/** Row type for {} queries. */", query_name);
        let _ = writeln!(out, "export interface {} {{", struct_name);
        for col in columns {
            let _ = writeln!(out, "\t{}: {};", col.field_name, col.full_type);
        }
        let _ = write!(out, "}}");
        Ok(out)
    }

    fn generate_model_struct(&self, table_name: &str, columns: &[ResolvedColumn]) -> Result<String, ScytheError> {
        let singular = singularize(table_name);
        let name = to_pascal_case(&singular);
        self.generate_row_struct(&name, columns)
    }

    fn generate_query_fn(
        &self,
        analyzed: &AnalyzedQuery,
        struct_name: &str,
        _columns: &[ResolvedColumn],
        params: &[ResolvedParam],
    ) -> Result<String, ScytheError> {
        let func_name = fn_name(&analyzed.name, &self.manifest.naming);
        let mut out = String::new();

        // Build parameter list
        let param_list = params
            .iter()
            .map(|p| format!("{}: {}", p.field_name, p.full_type))
            .collect::<Vec<_>>()
            .join(", ");
        let _sep = if param_list.is_empty() { "" } else { ", " };

        // Clean SQL — pg uses $1, $2 positional params natively
        let sql = super::clean_sql_with_optional(&analyzed.sql, &analyzed.optional_params, &analyzed.params);

        // Build array of param values
        let _param_array: String = if params.is_empty() {
            String::new()
        } else {
            let args: Vec<String> = params.iter().map(|p| p.field_name.clone()).collect();
            format!(", [{}]", args.join(", "))
        };

        // Build inline params string for line-length checking
        let inline_params = if params.is_empty() {
            "client: PoolClient".to_string()
        } else {
            format!("client: PoolClient, {}", param_list)
        };

        // Helper: write a typed query call (with generic type annotation).
        // Biome always breaks `client.query<T>(...)` to multi-line.
        let write_typed_query =
            |out: &mut String, prefix: &str, type_name: &str, sql: &str, params: &[ResolvedParam]| {
                let _ = writeln!(out, "{}client.query<{}>(", prefix, type_name);
                let _ = writeln!(out, "\t\t`{}`,", sql);
                if !params.is_empty() {
                    let args: Vec<String> = params.iter().map(|p| p.field_name.clone()).collect();
                    let _ = writeln!(out, "\t\t[{}],", args.join(", "));
                }
                let _ = writeln!(out, "\t);");
            };

        // Helper: write an untyped query call. Inline if short, multi-line if long.
        let write_untyped_query = |out: &mut String, prefix: &str, sql: &str, params: &[ResolvedParam]| {
            let param_str = if params.is_empty() {
                String::new()
            } else {
                let args: Vec<String> = params.iter().map(|p| p.field_name.clone()).collect();
                format!(", [{}]", args.join(", "))
            };
            let oneliner = format!("{}client.query(`{}`{});", prefix, sql, param_str);
            // Use tab width of 4 for line length estimation
            let estimated_len = oneliner.replace('\t', "    ").len();
            if estimated_len <= 80 {
                let _ = writeln!(out, "{}", oneliner);
            } else {
                let _ = writeln!(out, "{}client.query(", prefix);
                let _ = writeln!(out, "\t\t`{}`,", sql);
                if !params.is_empty() {
                    let args: Vec<String> = params.iter().map(|p| p.field_name.clone()).collect();
                    let _ = writeln!(out, "\t\t[{}],", args.join(", "));
                }
                let _ = writeln!(out, "\t);");
            }
        };

        // Helper: write function signature, inline or multi-line based on length
        let write_fn_sig = |out: &mut String, name: &str, params_inline: &str, ret: &str| {
            let oneliner = format!("export async function {}({}): {} {{", name, params_inline, ret);
            if oneliner.len() <= 80 {
                let _ = writeln!(out, "{}", oneliner);
            } else {
                let mut parts = vec!["\tclient: PoolClient".to_string()];
                for p in params {
                    parts.push(format!("\t{}: {}", p.field_name, p.full_type));
                }
                let _ = writeln!(out, "export async function {}(", name);
                for part in &parts {
                    let _ = writeln!(out, "{},", part);
                }
                let _ = writeln!(out, "): {} {{", ret);
            }
        };

        match &analyzed.command {
            QueryCommand::One | QueryCommand::Opt => {
                let _ = writeln!(out, "/** Fetch a single {} or null. */", struct_name);
                let ret = format!("Promise<{} | null>", struct_name);
                write_fn_sig(&mut out, &func_name, &inline_params, &ret);
                write_typed_query(&mut out, "\tconst { rows } = await ", struct_name, &sql, params);
                let _ = writeln!(out, "\treturn rows[0] ?? null;");
                let _ = write!(out, "}}");
            }
            QueryCommand::Many => {
                let _ = writeln!(out, "/** Fetch all {} rows. */", struct_name);
                let ret = format!("Promise<{}[]>", struct_name);
                write_fn_sig(&mut out, &func_name, &inline_params, &ret);
                write_typed_query(&mut out, "\tconst { rows } = await ", struct_name, &sql, params);
                let _ = writeln!(out, "\treturn rows;");
                let _ = write!(out, "}}");
            }
            QueryCommand::Batch => {
                let batch_fn_name = format!("{}Batch", func_name);
                // Build params interface
                if params.len() > 1 {
                    let params_type_name = format!("{}BatchParams", struct_name);
                    let _ = writeln!(out, "/** Params for {} batch operation. */", struct_name);
                    let _ = writeln!(out, "export interface {} {{", params_type_name);
                    for p in params {
                        let _ = writeln!(out, "\t{}: {};", p.field_name, p.full_type);
                    }
                    let _ = writeln!(out, "}}");
                    let _ = writeln!(out);
                    let _ = writeln!(
                        out,
                        "/** Execute {} for each item in the batch within a transaction. */",
                        analyzed.name
                    );
                    let batch_params = format!("client: PoolClient, items: {}[]", params_type_name);
                    write_fn_sig(&mut out, &batch_fn_name, &batch_params, "Promise<void>");
                    let _ = writeln!(out, "\ttry {{");
                    let _ = writeln!(out, "\t\tawait client.query(\"BEGIN\");");
                    let _ = writeln!(out, "\t\tfor (const item of items) {{");
                    let _ = writeln!(out, "\t\t\tawait client.query(");
                    let _ = writeln!(out, "\t\t\t\t`{}`,", sql);
                    let args: Vec<String> = params.iter().map(|p| format!("item.{}", p.field_name)).collect();
                    let _ = writeln!(out, "\t\t\t\t[{}],", args.join(", "));
                    let _ = writeln!(out, "\t\t\t);");
                    let _ = writeln!(out, "\t\t}}");
                    let _ = writeln!(out, "\t\tawait client.query(\"COMMIT\");");
                    let _ = writeln!(out, "\t}} catch (error) {{");
                    let _ = writeln!(out, "\t\tawait client.query(\"ROLLBACK\");");
                    let _ = writeln!(out, "\t\tthrow error;");
                    let _ = writeln!(out, "\t}}");
                    let _ = write!(out, "}}");
                } else if params.len() == 1 {
                    let _ = writeln!(
                        out,
                        "/** Execute {} for each item in the batch within a transaction. */",
                        analyzed.name
                    );
                    let batch_params = format!("client: PoolClient, items: {}[]", params[0].full_type);
                    write_fn_sig(&mut out, &batch_fn_name, &batch_params, "Promise<void>");
                    let _ = writeln!(out, "\ttry {{");
                    let _ = writeln!(out, "\t\tawait client.query(\"BEGIN\");");
                    let _ = writeln!(out, "\t\tfor (const item of items) {{");
                    let _ = writeln!(out, "\t\t\tawait client.query(`{}`, [item]);", sql);
                    let _ = writeln!(out, "\t\t}}");
                    let _ = writeln!(out, "\t\tawait client.query(\"COMMIT\");");
                    let _ = writeln!(out, "\t}} catch (error) {{");
                    let _ = writeln!(out, "\t\tawait client.query(\"ROLLBACK\");");
                    let _ = writeln!(out, "\t\tthrow error;");
                    let _ = writeln!(out, "\t}}");
                    let _ = write!(out, "}}");
                } else {
                    let _ = writeln!(
                        out,
                        "/** Execute {} for each item in the batch within a transaction. */",
                        analyzed.name
                    );
                    write_fn_sig(
                        &mut out,
                        &batch_fn_name,
                        "client: PoolClient, count: number",
                        "Promise<void>",
                    );
                    let _ = writeln!(out, "\ttry {{");
                    let _ = writeln!(out, "\t\tawait client.query(\"BEGIN\");");
                    let _ = writeln!(out, "\t\tfor (let i = 0; i < count; i++) {{");
                    let _ = writeln!(out, "\t\t\tawait client.query(`{}`);", sql);
                    let _ = writeln!(out, "\t\t}}");
                    let _ = writeln!(out, "\t\tawait client.query(\"COMMIT\");");
                    let _ = writeln!(out, "\t}} catch (error) {{");
                    let _ = writeln!(out, "\t\tawait client.query(\"ROLLBACK\");");
                    let _ = writeln!(out, "\t\tthrow error;");
                    let _ = writeln!(out, "\t}}");
                    let _ = write!(out, "}}");
                }
            }
            QueryCommand::Exec => {
                let _ = writeln!(out, "/** Execute a query returning no rows. */");
                write_fn_sig(&mut out, &func_name, &inline_params, "Promise<void>");
                write_untyped_query(&mut out, "\tawait ", &sql, params);
                let _ = write!(out, "}}");
            }
            QueryCommand::ExecResult | QueryCommand::ExecRows => {
                let _ = writeln!(out, "/** Execute a query and return the number of affected rows. */");
                write_fn_sig(&mut out, &func_name, &inline_params, "Promise<number>");
                write_untyped_query(&mut out, "\tconst result = await ", &sql, params);
                let _ = writeln!(out, "\treturn result.rowCount ?? 0;");
                let _ = write!(out, "}}");
            }
            QueryCommand::Grouped => {
                unreachable!("Grouped command is routed through generate_grouped_query_fn, not generate_query_fn")
            }
        }

        Ok(out)
    }

    fn generate_grouped_structs(
        &self,
        parent_struct_name: &str,
        child_struct_name: &str,
        parent_columns: &[ResolvedColumn],
        child_columns: &[ResolvedColumn],
        _key_column: &str,
    ) -> Result<String, ScytheError> {
        if self.row_type == TsRowType::Zod {
            return Ok(generate_zod_grouped_structs(
                child_struct_name,
                parent_struct_name,
                parent_columns,
                child_columns,
            ));
        }
        Ok(generate_grouped_interface_structs(
            child_struct_name,
            parent_struct_name,
            parent_columns,
            child_columns,
        ))
    }

    fn generate_grouped_query_fn(&self, request: &GroupedQueryFn<'_>) -> Result<String, ScytheError> {
        let analyzed = request.analyzed;
        let parent_struct_name = request.parent_struct_name;
        let child_struct_name = request.child_struct_name;
        let parent_columns = request.parent_columns;
        let child_columns = request.child_columns;
        let params = request.params;
        let key_column = request.key_column;

        let func_name = fn_name(&analyzed.name, &self.manifest.naming);
        let sql = super::clean_sql_with_optional(&analyzed.sql, &analyzed.optional_params, &analyzed.params);
        let mut out = String::new();

        let param_list = params
            .iter()
            .map(|p| format!("{}: {}", p.field_name, p.full_type))
            .collect::<Vec<_>>()
            .join(", ");
        let inline_params = if params.is_empty() {
            "client: PoolClient".to_string()
        } else {
            format!("client: PoolClient, {}", param_list)
        };
        let ret = format!("Promise<{parent_struct_name}[]>");

        // Function signature
        let oneliner = format!("export async function {func_name}({inline_params}): {ret} {{");
        if oneliner.len() <= 80 {
            let _ = writeln!(out, "/** Fetch grouped {} rows. */", analyzed.name);
            let _ = writeln!(out, "{oneliner}");
        } else {
            let _ = writeln!(out, "/** Fetch grouped {} rows. */", analyzed.name);
            let _ = writeln!(out, "export async function {func_name}(");
            let _ = writeln!(out, "\tclient: PoolClient,");
            for p in params {
                let _ = writeln!(out, "\t{}: {},", p.field_name, p.full_type);
            }
            let _ = writeln!(out, "): {ret} {{");
        }

        // Fetch flat rows — no typed generic so rows are Record<string, any>
        let _ = writeln!(out, "\tconst {{ rows: flatRows }} = await client.query(");
        let _ = writeln!(out, "\t\t`{sql}`,");
        if !params.is_empty() {
            let args: Vec<String> = params.iter().map(|p| p.field_name.clone()).collect();
            let _ = writeln!(out, "\t\t[{}],", args.join(", "));
        }
        let _ = writeln!(out, "\t);");

        // Fold — rows are Record<string, any>, so dot-access returns any (no cast needed)
        let fold = generate_ts_grouped_fold_body(
            parent_struct_name,
            child_struct_name,
            parent_columns,
            child_columns,
            key_column,
            |name, _ty| format!("row.{name}"),
        );
        out.push_str(&fold);
        let _ = write!(out, "}}");
        Ok(out)
    }

    fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
        let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
        if self.row_type == TsRowType::Zod {
            return Ok(generate_zod_enum(&type_name, &enum_info.values));
        }
        let mut out = String::new();
        let values_name = format!("{}Values", type_name);
        let _ = writeln!(out, "export const {} = {{", values_name);
        for value in &enum_info.values {
            let variant = enum_variant_name(value, &self.manifest.naming);
            let _ = writeln!(out, "\t{}: \"{}\",", variant, value);
        }
        let _ = writeln!(out, "}} as const;");
        let _ = writeln!(out);
        let _ = write!(
            out,
            "export type {} = typeof {}[keyof typeof {}];",
            type_name, values_name, values_name
        );
        Ok(out)
    }

    fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
        let name = to_pascal_case(&composite.sql_name);
        let mut out = String::new();
        let _ = writeln!(out, "/** Composite type {}. */", composite.sql_name);
        let _ = writeln!(out, "export interface {} {{", name);
        if composite.fields.is_empty() {
            // empty interface
        } else {
            for field in &composite.fields {
                let ts_type = resolve_type(&field.neutral_type, &self.manifest, false)
                    .map(|t| t.into_owned())
                    .map_err(|e| {
                        ScytheError::new(ErrorCode::InternalError, format!("composite field type error: {}", e))
                    })?;
                let _ = writeln!(out, "\t{}: {};", to_camel_case(&field.name), ts_type);
            }
        }
        let _ = write!(out, "}}");
        Ok(out)
    }

    fn apply_options(&mut self, options: &std::collections::HashMap<String, String>) -> Result<(), ScytheError> {
        if let Some(value) = options.get("row_type") {
            self.row_type = TsRowType::from_option(value)?;
        }
        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use super::TypescriptPgBackend;
    use scythe_core::analyzer::{AnalyzedColumn, AnalyzedQuery, GroupByConfig};
    use scythe_core::parser::QueryCommand;

    fn make_grouped_query() -> AnalyzedQuery {
        let parent_cols = vec![
            AnalyzedColumn {
                name: "id".to_string(),
                neutral_type: "int32".to_string(),
                nullable: false,
            },
            AnalyzedColumn {
                name: "name".to_string(),
                neutral_type: "string".to_string(),
                nullable: false,
            },
            AnalyzedColumn {
                name: "email".to_string(),
                neutral_type: "string".to_string(),
                nullable: false,
            },
        ];
        let child_cols = vec![
            AnalyzedColumn {
                name: "order_id".to_string(),
                neutral_type: "int32".to_string(),
                nullable: false,
            },
            AnalyzedColumn {
                name: "total".to_string(),
                neutral_type: "decimal".to_string(),
                nullable: true,
            },
            AnalyzedColumn {
                name: "order_date".to_string(),
                neutral_type: "datetime".to_string(),
                nullable: false,
            },
        ];
        let all_cols = [parent_cols.clone(), child_cols.clone()].concat();
        AnalyzedQuery {
            name: "GetUsersWithOrders".to_string(),
            command: QueryCommand::Grouped,
            sql: "SELECT u.id, u.name, u.email, o.id AS order_id, o.total, o.created_at AS order_date\nFROM users u\nJOIN orders o ON o.user_id = u.id".to_string(),
            columns: all_cols,
            params: vec![],
            deprecated: None,
            source_table: None,
            composites: vec![],
            enums: vec![],
            optional_params: vec![],
            group_by: Some(GroupByConfig {
                table: "users".to_string(),
                key_column: "id".to_string(),
                parent_columns: parent_cols,
                child_columns: child_cols,
            }),
            custom: vec![],
        }
    }

    #[test]
    fn test_grouped_typescript_pg_structs() {
        let backend = TypescriptPgBackend::new("postgresql").unwrap();
        let query = make_grouped_query();
        let result = crate::generate_with_backend(&query, &backend).unwrap();
        let row_struct = result.row_struct.as_deref().unwrap();

        assert!(
            row_struct.contains("interface GetUsersWithOrdersChildRow"),
            "missing child; got:\n{row_struct}"
        );
        assert!(
            row_struct.contains("order_id: number"),
            "child missing order_id; got:\n{row_struct}"
        );
        assert!(
            row_struct.contains("interface GetUsersWithOrdersRow"),
            "missing parent; got:\n{row_struct}"
        );
        assert!(
            row_struct.contains("id: number"),
            "parent missing id; got:\n{row_struct}"
        );
        assert!(
            row_struct.contains("children: GetUsersWithOrdersChildRow[]"),
            "missing children; got:\n{row_struct}"
        );
        let child_pos = row_struct.find("GetUsersWithOrdersChildRow").unwrap();
        let parent_pos = row_struct.find("interface GetUsersWithOrdersRow").unwrap();
        assert!(child_pos < parent_pos, "child must precede parent");
        assert!(result.model_struct.is_none(), "grouped must not produce model_struct");
    }

    #[test]
    fn test_grouped_typescript_pg_query_fn() {
        let backend = TypescriptPgBackend::new("postgresql").unwrap();
        let query = make_grouped_query();
        let result = crate::generate_with_backend(&query, &backend).unwrap();
        let query_fn = result.query_fn.as_deref().unwrap();

        assert!(
            query_fn.contains("getUsersWithOrders"),
            "missing fn name; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("Promise<GetUsersWithOrdersRow[]>"),
            "wrong return type; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("client.query("),
            "must use client.query; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("new Map<unknown, GetUsersWithOrdersRow>()"),
            "must use Map; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("parent.children.push"),
            "must fold children; got:\n{query_fn}"
        );
        assert!(
            query_fn.contains("return result"),
            "must return result; got:\n{query_fn}"
        );
    }
}