1use std::fmt::Write;
2use std::path::Path;
3
4use scythe_backend::manifest::{BackendManifest, load_manifest};
5use scythe_backend::naming::{
6 enum_type_name, enum_variant_name, fn_name, row_struct_name, to_pascal_case,
7};
8use scythe_backend::types::resolve_type;
9
10use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
11use scythe_core::errors::{ErrorCode, ScytheError};
12use scythe_core::parser::QueryCommand;
13
14use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
15
16pub struct GoDatabaseSqlBackend {
17 manifest: BackendManifest,
18 engine: String,
19}
20
21impl GoDatabaseSqlBackend {
22 pub fn new(engine: &str) -> Result<Self, ScytheError> {
23 let manifest_toml = match engine {
24 "mysql" | "mariadb" => include_str!("../../manifests/go-database-sql.mysql.toml"),
25 "sqlite" | "sqlite3" => include_str!("../../manifests/go-database-sql.sqlite.toml"),
26 _ => {
27 return Err(ScytheError::new(
28 ErrorCode::InternalError,
29 format!(
30 "go-database-sql supports MySQL and SQLite, got engine '{}'",
31 engine
32 ),
33 ));
34 }
35 };
36 let manifest_path = Path::new("backends/go-database-sql/manifest.toml");
37 let manifest = if manifest_path.exists() {
38 load_manifest(manifest_path)
39 .map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
40 } else {
41 toml::from_str(manifest_toml)
42 .map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
43 };
44 Ok(Self {
45 manifest,
46 engine: engine.to_string(),
47 })
48 }
49}
50
51impl CodegenBackend for GoDatabaseSqlBackend {
52 fn name(&self) -> &str {
53 "go-database-sql"
54 }
55
56 fn manifest(&self) -> &scythe_backend::manifest::BackendManifest {
57 &self.manifest
58 }
59
60 fn supported_engines(&self) -> &[&str] {
61 &["mysql", "sqlite"]
62 }
63
64 fn file_header(&self) -> String {
65 let uses_time = matches!(self.engine.as_str(), "mysql" | "mariadb");
66 let mut header =
67 String::from("package queries\n\nimport (\n\t\"context\"\n\t\"database/sql\"");
68 if uses_time {
69 header.push_str("\n\t\"time\"");
70 }
71 header.push_str("\n)\n");
72 header
73 }
74
75 fn generate_row_struct(
76 &self,
77 query_name: &str,
78 columns: &[ResolvedColumn],
79 ) -> Result<String, ScytheError> {
80 let struct_name = row_struct_name(query_name, &self.manifest.naming);
81 let mut out = String::new();
82 let _ = writeln!(out, "type {} struct {{", struct_name);
83 for col in columns {
84 let field = to_pascal_case(&col.field_name);
85 let json_tag = &col.field_name;
86 let _ = writeln!(out, "\t{} {} `json:\"{}\"`", field, col.full_type, json_tag);
87 }
88 let _ = write!(out, "}}");
89 Ok(out)
90 }
91
92 fn generate_model_struct(
93 &self,
94 table_name: &str,
95 columns: &[ResolvedColumn],
96 ) -> Result<String, ScytheError> {
97 let name = to_pascal_case(table_name);
98 self.generate_row_struct(&name, columns)
99 }
100
101 fn generate_query_fn(
102 &self,
103 analyzed: &AnalyzedQuery,
104 struct_name: &str,
105 columns: &[ResolvedColumn],
106 params: &[ResolvedParam],
107 ) -> Result<String, ScytheError> {
108 let func_name = fn_name(&analyzed.name, &self.manifest.naming);
109 let sql = super::clean_sql_oneline(&analyzed.sql);
110
111 let param_list = params
112 .iter()
113 .map(|p| {
114 let field = to_pascal_case(&p.field_name);
115 format!("{} {}", field, p.full_type)
116 })
117 .collect::<Vec<_>>()
118 .join(", ");
119 let sep = if param_list.is_empty() { "" } else { ", " };
120
121 let args = params
122 .iter()
123 .map(|p| to_pascal_case(&p.field_name).into_owned())
124 .collect::<Vec<_>>();
125
126 let mut out = String::new();
127
128 match &analyzed.command {
129 QueryCommand::Exec => {
130 let _ = writeln!(
131 out,
132 "func {}(ctx context.Context, db *sql.DB{}{}) error {{",
133 func_name, sep, param_list
134 );
135 let args_str = if args.is_empty() {
136 String::new()
137 } else {
138 format!(", {}", args.join(", "))
139 };
140 let _ = writeln!(
141 out,
142 "\t_, err := db.ExecContext(ctx, \"{}\"{})",
143 sql, args_str
144 );
145 let _ = writeln!(out, "\treturn err");
146 let _ = write!(out, "}}");
147 }
148 QueryCommand::ExecResult | QueryCommand::ExecRows => {
149 let _ = writeln!(
150 out,
151 "func {}(ctx context.Context, db *sql.DB{}{}) (int64, error) {{",
152 func_name, sep, param_list
153 );
154 let args_str = if args.is_empty() {
155 String::new()
156 } else {
157 format!(", {}", args.join(", "))
158 };
159 let _ = writeln!(
160 out,
161 "\tresult, err := db.ExecContext(ctx, \"{}\"{})",
162 sql, args_str
163 );
164 let _ = writeln!(out, "\tif err != nil {{");
165 let _ = writeln!(out, "\t\treturn 0, err");
166 let _ = writeln!(out, "\t}}");
167 let _ = writeln!(out, "\treturn result.RowsAffected()");
168 let _ = write!(out, "}}");
169 }
170 QueryCommand::One => {
171 let _ = writeln!(
172 out,
173 "func {}(ctx context.Context, db *sql.DB{}{}) ({}, error) {{",
174 func_name, sep, param_list, struct_name
175 );
176 let args_str = if args.is_empty() {
177 String::new()
178 } else {
179 format!(", {}", args.join(", "))
180 };
181 let _ = writeln!(
182 out,
183 "\trow := db.QueryRowContext(ctx, \"{}\"{})",
184 sql, args_str
185 );
186 let _ = writeln!(out, "\tvar r {}", struct_name);
187 let scan_fields: Vec<String> = columns
188 .iter()
189 .map(|c| format!("&r.{}", to_pascal_case(&c.field_name)))
190 .collect();
191 let _ = writeln!(out, "\terr := row.Scan({})", scan_fields.join(", "));
192 let _ = writeln!(out, "\treturn r, err");
193 let _ = write!(out, "}}");
194 }
195 QueryCommand::Many | QueryCommand::Batch => {
196 let _ = writeln!(
197 out,
198 "func {}(ctx context.Context, db *sql.DB{}{}) ([]{}, error) {{",
199 func_name, sep, param_list, struct_name
200 );
201 let args_str = if args.is_empty() {
202 String::new()
203 } else {
204 format!(", {}", args.join(", "))
205 };
206 let _ = writeln!(
207 out,
208 "\trows, err := db.QueryContext(ctx, \"{}\"{})",
209 sql, args_str
210 );
211 let _ = writeln!(out, "\tif err != nil {{");
212 let _ = writeln!(out, "\t\treturn nil, err");
213 let _ = writeln!(out, "\t}}");
214 let _ = writeln!(out, "\tdefer rows.Close()");
215 let _ = writeln!(out, "\tvar result []{}", struct_name);
216 let _ = writeln!(out, "\tfor rows.Next() {{");
217 let _ = writeln!(out, "\t\tvar r {}", struct_name);
218 let scan_fields: Vec<String> = columns
219 .iter()
220 .map(|c| format!("&r.{}", to_pascal_case(&c.field_name)))
221 .collect();
222 let _ = writeln!(
223 out,
224 "\t\tif err := rows.Scan({}); err != nil {{",
225 scan_fields.join(", ")
226 );
227 let _ = writeln!(out, "\t\t\treturn nil, err");
228 let _ = writeln!(out, "\t\t}}");
229 let _ = writeln!(out, "\t\tresult = append(result, r)");
230 let _ = writeln!(out, "\t}}");
231 let _ = writeln!(out, "\treturn result, rows.Err()");
232 let _ = write!(out, "}}");
233 }
234 }
235
236 Ok(out)
237 }
238
239 fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
240 let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
241 let mut out = String::new();
242 let _ = writeln!(out, "type {} string", type_name);
243 let _ = writeln!(out);
244 let _ = writeln!(out, "const (");
245 for value in &enum_info.values {
246 let variant = enum_variant_name(value, &self.manifest.naming);
247 let _ = writeln!(
248 out,
249 "\t{}{} {} = \"{}\"",
250 type_name, variant, type_name, value
251 );
252 }
253 let _ = write!(out, ")");
254 Ok(out)
255 }
256
257 fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
258 let name = to_pascal_case(&composite.sql_name);
259 let mut out = String::new();
260 let _ = writeln!(out, "type {} struct {{", name);
261 if !composite.fields.is_empty() {
262 for field in &composite.fields {
263 let field_name = to_pascal_case(&field.name);
264 let go_type = resolve_type(&field.neutral_type, &self.manifest, false)
265 .map(|t| t.into_owned())
266 .unwrap_or_else(|_| "interface{}".to_string());
267 let json_tag = &field.name;
268 let _ = writeln!(out, "\t{} {} `json:\"{}\"`", field_name, go_type, json_tag);
269 }
270 }
271 let _ = write!(out, "}}");
272 Ok(out)
273 }
274}