use std::fmt::Write;
use std::path::Path;
use scythe_backend::manifest::{BackendManifest, load_manifest};
use scythe_backend::naming::{
enum_type_name, enum_variant_name, fn_name, row_struct_name, to_pascal_case,
};
use scythe_backend::types::resolve_type;
use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
use scythe_core::errors::{ErrorCode, ScytheError};
use scythe_core::parser::QueryCommand;
use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/go-pgx.toml");
pub struct GoPgxBackend {
manifest: BackendManifest,
}
impl GoPgxBackend {
pub fn new() -> Result<Self, ScytheError> {
let manifest_path = Path::new("backends/go-pgx/manifest.toml");
let manifest = if manifest_path.exists() {
load_manifest(manifest_path)
.map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
} else {
toml::from_str(DEFAULT_MANIFEST_TOML)
.map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
};
Ok(Self { manifest })
}
pub fn manifest(&self) -> &BackendManifest {
&self.manifest
}
}
impl CodegenBackend for GoPgxBackend {
fn name(&self) -> &str {
"go-pgx"
}
fn file_header(&self) -> String {
"package queries\n\nimport (\n\t\"context\"\n\n\t\"github.com/jackc/pgx/v5/pgxpool\"\n)\n"
.to_string()
}
fn generate_row_struct(
&self,
query_name: &str,
columns: &[ResolvedColumn],
) -> Result<String, ScytheError> {
let struct_name = row_struct_name(query_name, &self.manifest.naming);
let mut out = String::new();
let _ = writeln!(out, "type {} struct {{", struct_name);
for col in columns {
let field = to_pascal_case(&col.field_name);
let json_tag = &col.field_name;
let _ = writeln!(out, "\t{} {} `json:\"{}\"`", field, col.full_type, json_tag);
}
let _ = write!(out, "}}");
Ok(out)
}
fn generate_model_struct(
&self,
table_name: &str,
columns: &[ResolvedColumn],
) -> Result<String, ScytheError> {
let name = to_pascal_case(table_name);
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 sql = super::clean_sql_oneline(&analyzed.sql);
let param_list = params
.iter()
.map(|p| {
let field = to_pascal_case(&p.field_name);
format!("{} {}", field, p.full_type)
})
.collect::<Vec<_>>()
.join(", ");
let sep = if param_list.is_empty() { "" } else { ", " };
let args = params
.iter()
.map(|p| to_pascal_case(&p.field_name).into_owned())
.collect::<Vec<_>>();
let mut out = String::new();
match &analyzed.command {
QueryCommand::Exec => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *pgxpool.Pool{}{}) error {{",
func_name, sep, param_list
);
let args_str = if args.is_empty() {
String::new()
} else {
format!(", {}", args.join(", "))
};
let _ = writeln!(out, "\t_, err := db.Exec(ctx, \"{}\"{})", sql, args_str);
let _ = writeln!(out, "\treturn err");
let _ = write!(out, "}}");
}
QueryCommand::ExecResult | QueryCommand::ExecRows => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *pgxpool.Pool{}{}) (int64, error) {{",
func_name, sep, param_list
);
let args_str = if args.is_empty() {
String::new()
} else {
format!(", {}", args.join(", "))
};
let _ = writeln!(
out,
"\tresult, err := db.Exec(ctx, \"{}\"{})",
sql, args_str
);
let _ = writeln!(out, "\tif err != nil {{");
let _ = writeln!(out, "\t\treturn 0, err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn result.RowsAffected(), nil");
let _ = write!(out, "}}");
}
QueryCommand::One => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *pgxpool.Pool{}{}) ({}, error) {{",
func_name, sep, param_list, struct_name
);
let args_str = if args.is_empty() {
String::new()
} else {
format!(", {}", args.join(", "))
};
let _ = writeln!(out, "\trow := db.QueryRow(ctx, \"{}\"{})", sql, args_str);
let _ = writeln!(out, "\tvar r {}", struct_name);
let scan_fields: Vec<String> = columns
.iter()
.map(|c| format!("&r.{}", to_pascal_case(&c.field_name)))
.collect();
let _ = writeln!(out, "\terr := row.Scan({})", scan_fields.join(", "));
let _ = writeln!(out, "\treturn r, err");
let _ = write!(out, "}}");
}
QueryCommand::Many | QueryCommand::Batch => {
let _ = writeln!(
out,
"func {}(ctx context.Context, db *pgxpool.Pool{}{}) ([]{}, error) {{",
func_name, sep, param_list, struct_name
);
let args_str = if args.is_empty() {
String::new()
} else {
format!(", {}", args.join(", "))
};
let _ = writeln!(out, "\trows, err := db.Query(ctx, \"{}\"{})", sql, args_str);
let _ = writeln!(out, "\tif err != nil {{");
let _ = writeln!(out, "\t\treturn nil, err");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\tdefer rows.Close()");
let _ = writeln!(out, "\tvar result []{}", struct_name);
let _ = writeln!(out, "\tfor rows.Next() {{");
let _ = writeln!(out, "\t\tvar r {}", struct_name);
let scan_fields: Vec<String> = columns
.iter()
.map(|c| format!("&r.{}", to_pascal_case(&c.field_name)))
.collect();
let _ = writeln!(
out,
"\t\tif err := rows.Scan({}); err != nil {{",
scan_fields.join(", ")
);
let _ = writeln!(out, "\t\t\treturn nil, err");
let _ = writeln!(out, "\t\t}}");
let _ = writeln!(out, "\t\tresult = append(result, r)");
let _ = writeln!(out, "\t}}");
let _ = writeln!(out, "\treturn result, rows.Err()");
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);
let mut out = String::new();
let _ = writeln!(out, "type {} string", type_name);
let _ = writeln!(out);
let _ = writeln!(out, "const (");
for value in &enum_info.values {
let variant = enum_variant_name(value, &self.manifest.naming);
let _ = writeln!(
out,
"\t{}{} {} = \"{}\"",
type_name, variant, type_name, value
);
}
let _ = write!(out, ")");
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, "type {} struct {{", name);
if composite.fields.is_empty() {
} else {
for field in &composite.fields {
let field_name = to_pascal_case(&field.name);
let go_type = resolve_type(&field.neutral_type, &self.manifest, false)
.map(|t| t.into_owned())
.unwrap_or_else(|_| "interface{}".to_string());
let json_tag = &field.name;
let _ = writeln!(out, "\t{} {} `json:\"{}\"`", field_name, go_type, json_tag);
}
}
let _ = write!(out, "}}");
Ok(out)
}
}