scythe_codegen/backends/
elixir_myxql.rs

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, to_snake_case,
7};
8
9use scythe_core::analyzer::{AnalyzedQuery, CompositeInfo, EnumInfo};
10use scythe_core::errors::{ErrorCode, ScytheError};
11use scythe_core::parser::QueryCommand;
12
13use crate::backend_trait::{CodegenBackend, ResolvedColumn, ResolvedParam};
14
15const DEFAULT_MANIFEST_TOML: &str = include_str!("../../manifests/elixir-myxql.toml");
16
17pub struct ElixirMyxqlBackend {
18    manifest: BackendManifest,
19}
20
21impl ElixirMyxqlBackend {
22    pub fn new(engine: &str) -> Result<Self, ScytheError> {
23        match engine {
24            "mysql" | "mariadb" => {}
25            _ => {
26                return Err(ScytheError::new(
27                    ErrorCode::InternalError,
28                    format!("elixir-myxql only supports MySQL, got engine '{}'", engine),
29                ));
30            }
31        }
32        let manifest_path = Path::new("backends/elixir-myxql/manifest.toml");
33        let manifest = if manifest_path.exists() {
34            load_manifest(manifest_path)
35                .map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
36        } else {
37            toml::from_str(DEFAULT_MANIFEST_TOML)
38                .map_err(|e| ScytheError::new(ErrorCode::InternalError, format!("manifest: {e}")))?
39        };
40        Ok(Self { manifest })
41    }
42}
43
44impl CodegenBackend for ElixirMyxqlBackend {
45    fn name(&self) -> &str {
46        "elixir-myxql"
47    }
48
49    fn manifest(&self) -> &scythe_backend::manifest::BackendManifest {
50        &self.manifest
51    }
52
53    fn supported_engines(&self) -> &[&str] {
54        &["mysql"]
55    }
56
57    fn generate_row_struct(
58        &self,
59        query_name: &str,
60        columns: &[ResolvedColumn],
61    ) -> Result<String, ScytheError> {
62        let struct_name = row_struct_name(query_name, &self.manifest.naming);
63        let mut out = String::new();
64        let _ = writeln!(out, "defmodule {} do", struct_name);
65        let _ = writeln!(out, "  @moduledoc \"Row type for {} queries.\"", query_name);
66        let _ = writeln!(out);
67
68        // Generate typespec
69        let _ = writeln!(out, "  @type t :: %__MODULE__{{");
70        for (i, c) in columns.iter().enumerate() {
71            let sep = if i + 1 < columns.len() { "," } else { "" };
72            let _ = writeln!(out, "    {}: {}{}", c.field_name, c.full_type, sep);
73        }
74        let _ = writeln!(out, "  }}");
75
76        // Generate defstruct
77        let fields = columns
78            .iter()
79            .map(|c| format!(":{}", c.field_name))
80            .collect::<Vec<_>>()
81            .join(", ");
82        let _ = writeln!(out, "  defstruct [{}]", fields);
83        let _ = write!(out, "end");
84        Ok(out)
85    }
86
87    fn generate_model_struct(
88        &self,
89        table_name: &str,
90        columns: &[ResolvedColumn],
91    ) -> Result<String, ScytheError> {
92        let name = to_pascal_case(table_name);
93        self.generate_row_struct(&name, columns)
94    }
95
96    fn generate_query_fn(
97        &self,
98        analyzed: &AnalyzedQuery,
99        struct_name: &str,
100        columns: &[ResolvedColumn],
101        params: &[ResolvedParam],
102    ) -> Result<String, ScytheError> {
103        let func_name = fn_name(&analyzed.name, &self.manifest.naming);
104        let sql = super::clean_sql(&analyzed.sql);
105        let mut out = String::new();
106
107        // Parameter list
108        let param_list = params
109            .iter()
110            .map(|p| p.field_name.clone())
111            .collect::<Vec<_>>()
112            .join(", ");
113        let sep = if param_list.is_empty() { "" } else { ", " };
114
115        // Build the params list for MyXQL.query
116        let param_args = if params.is_empty() {
117            "[]".to_string()
118        } else {
119            format!(
120                "[{}]",
121                params
122                    .iter()
123                    .map(|p| p.field_name.clone())
124                    .collect::<Vec<_>>()
125                    .join(", ")
126            )
127        };
128
129        // Build @spec
130        let param_specs = if params.is_empty() {
131            String::new()
132        } else {
133            let specs: Vec<String> = params.iter().map(|p| p.full_type.clone()).collect();
134            format!(", {}", specs.join(", "))
135        };
136        match &analyzed.command {
137            QueryCommand::One => {
138                let _ = writeln!(
139                    out,
140                    "@spec {}(pid(){}) :: {{:ok, %{}{{}}}} | {{:error, term()}}",
141                    func_name, param_specs, struct_name
142                );
143            }
144            QueryCommand::Many | QueryCommand::Batch => {
145                let _ = writeln!(
146                    out,
147                    "@spec {}(pid(){}) :: {{:ok, [%{}{{}}]}} | {{:error, term()}}",
148                    func_name, param_specs, struct_name
149                );
150            }
151            QueryCommand::Exec => {
152                let _ = writeln!(
153                    out,
154                    "@spec {}(pid(){}) :: :ok | {{:error, term()}}",
155                    func_name, param_specs
156                );
157            }
158            QueryCommand::ExecResult | QueryCommand::ExecRows => {
159                let _ = writeln!(
160                    out,
161                    "@spec {}(pid(){}) :: {{:ok, non_neg_integer()}} | {{:error, term()}}",
162                    func_name, param_specs
163                );
164            }
165        }
166        let _ = writeln!(out, "def {}(conn{}{}) do", func_name, sep, param_list);
167
168        match &analyzed.command {
169            QueryCommand::One => {
170                let _ = writeln!(
171                    out,
172                    "  case MyXQL.query(conn, \"{}\", {}) do",
173                    sql, param_args
174                );
175                let _ = writeln!(out, "    {{:ok, %MyXQL.Result{{rows: [row]}}}} ->");
176
177                let field_vars = columns
178                    .iter()
179                    .map(|c| c.field_name.clone())
180                    .collect::<Vec<_>>()
181                    .join(", ");
182                let _ = writeln!(out, "      [{}] = row", field_vars);
183
184                let struct_fields = columns
185                    .iter()
186                    .map(|c| format!("{}: {}", c.field_name, c.field_name))
187                    .collect::<Vec<_>>()
188                    .join(", ");
189                let _ = writeln!(out, "      {{:ok, %{}{{{}}}}}", struct_name, struct_fields);
190                let _ = writeln!(
191                    out,
192                    "    {{:ok, %MyXQL.Result{{rows: []}}}} -> {{:error, :not_found}}"
193                );
194                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
195                let _ = writeln!(out, "  end");
196            }
197            QueryCommand::Many | QueryCommand::Batch => {
198                let _ = writeln!(
199                    out,
200                    "  case MyXQL.query(conn, \"{}\", {}) do",
201                    sql, param_args
202                );
203                let _ = writeln!(out, "    {{:ok, %MyXQL.Result{{rows: rows}}}} ->");
204
205                let field_vars = columns
206                    .iter()
207                    .map(|c| c.field_name.clone())
208                    .collect::<Vec<_>>()
209                    .join(", ");
210                let struct_fields = columns
211                    .iter()
212                    .map(|c| format!("{}: {}", c.field_name, c.field_name))
213                    .collect::<Vec<_>>()
214                    .join(", ");
215
216                let _ = writeln!(out, "      results = Enum.map(rows, fn row ->");
217                let _ = writeln!(out, "        [{}] = row", field_vars);
218                let _ = writeln!(out, "        %{}{{{}}}", struct_name, struct_fields);
219                let _ = writeln!(out, "      end)");
220                let _ = writeln!(out, "      {{:ok, results}}");
221                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
222                let _ = writeln!(out, "  end");
223            }
224            QueryCommand::Exec => {
225                let _ = writeln!(
226                    out,
227                    "  case MyXQL.query(conn, \"{}\", {}) do",
228                    sql, param_args
229                );
230                let _ = writeln!(out, "    {{:ok, _}} -> :ok");
231                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
232                let _ = writeln!(out, "  end");
233            }
234            QueryCommand::ExecResult | QueryCommand::ExecRows => {
235                let _ = writeln!(
236                    out,
237                    "  case MyXQL.query(conn, \"{}\", {}) do",
238                    sql, param_args
239                );
240                let _ = writeln!(
241                    out,
242                    "    {{:ok, %MyXQL.Result{{num_rows: n}}}} -> {{:ok, n}}"
243                );
244                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
245                let _ = writeln!(out, "  end");
246            }
247        }
248
249        let _ = write!(out, "end");
250        Ok(out)
251    }
252
253    fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
254        let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
255        let mut out = String::new();
256        let _ = writeln!(out, "defmodule {} do", type_name);
257        let _ = writeln!(
258            out,
259            "  @moduledoc \"Enum type for {}.\"",
260            enum_info.sql_name
261        );
262        let _ = writeln!(out);
263        let _ = writeln!(out, "  @type t :: String.t()");
264        for value in &enum_info.values {
265            let variant = enum_variant_name(value, &self.manifest.naming);
266            let _ = writeln!(
267                out,
268                "  def {}(), do: \"{}\"",
269                to_snake_case(&variant),
270                value
271            );
272        }
273        // values/0 function
274        let values_list = enum_info
275            .values
276            .iter()
277            .map(|v| format!("\"{}\"", v))
278            .collect::<Vec<_>>()
279            .join(", ");
280        let _ = writeln!(out, "  def values, do: [{}]", values_list);
281        let _ = write!(out, "end");
282        Ok(out)
283    }
284
285    fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
286        let name = to_pascal_case(&composite.sql_name);
287        let mut out = String::new();
288        let _ = writeln!(out, "defmodule {} do", name);
289        let _ = writeln!(
290            out,
291            "  @moduledoc \"Composite type for {}.\"",
292            composite.sql_name
293        );
294        let _ = writeln!(out);
295        if composite.fields.is_empty() {
296            let _ = writeln!(out, "  defstruct []");
297        } else {
298            let fields = composite
299                .fields
300                .iter()
301                .map(|f| format!(":{}", to_snake_case(&f.name)))
302                .collect::<Vec<_>>()
303                .join(", ");
304            let _ = writeln!(out, "  defstruct [{}]", fields);
305        }
306        let _ = write!(out, "end");
307        Ok(out)
308    }
309}
scythe_codegen/backends/elixir_myxql.rs

scythe_codegen/backends/
elixir_myxql.rs
