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_with_optional(
105            &analyzed.sql,
106            &analyzed.optional_params,
107            &analyzed.params,
108        );
109        let mut out = String::new();
110
111        // Parameter list
112        let param_list = params
113            .iter()
114            .map(|p| p.field_name.clone())
115            .collect::<Vec<_>>()
116            .join(", ");
117        let sep = if param_list.is_empty() { "" } else { ", " };
118
119        // Build the params list for MyXQL.query
120        let param_args = if params.is_empty() {
121            "[]".to_string()
122        } else {
123            format!(
124                "[{}]",
125                params
126                    .iter()
127                    .map(|p| p.field_name.clone())
128                    .collect::<Vec<_>>()
129                    .join(", ")
130            )
131        };
132
133        // Build @spec
134        let param_specs = if params.is_empty() {
135            String::new()
136        } else {
137            let specs: Vec<String> = params.iter().map(|p| p.full_type.clone()).collect();
138            format!(", {}", specs.join(", "))
139        };
140        match &analyzed.command {
141            QueryCommand::One => {
142                let _ = writeln!(
143                    out,
144                    "@spec {}(pid(){}) :: {{:ok, %{}{{}}}} | {{:error, term()}}",
145                    func_name, param_specs, struct_name
146                );
147            }
148            QueryCommand::Many => {
149                let _ = writeln!(
150                    out,
151                    "@spec {}(pid(){}) :: {{:ok, [%{}{{}}]}} | {{:error, term()}}",
152                    func_name, param_specs, struct_name
153                );
154            }
155            QueryCommand::Batch => {
156                let batch_fn_name = format!("{}_batch", func_name);
157                let _ = writeln!(
158                    out,
159                    "@spec {}(pid(), list()) :: :ok | {{:error, term()}}",
160                    batch_fn_name
161                );
162                let _ = writeln!(out, "def {}(conn, items) do", batch_fn_name);
163                let _ = writeln!(out, "  Enum.reduce_while(items, :ok, fn item, :ok ->");
164                if params.len() > 1 {
165                    let _ = writeln!(
166                        out,
167                        "    case MyXQL.query(conn, \"{}\", Tuple.to_list(item)) do",
168                        sql
169                    );
170                } else if params.len() == 1 {
171                    let _ = writeln!(out, "    case MyXQL.query(conn, \"{}\", [item]) do", sql);
172                } else {
173                    let _ = writeln!(out, "    case MyXQL.query(conn, \"{}\", []) do", sql);
174                }
175                let _ = writeln!(out, "      {{:ok, _}} -> {{:cont, :ok}}");
176                let _ = writeln!(out, "      {{:error, err}} -> {{:halt, {{:error, err}}}}");
177                let _ = writeln!(out, "    end");
178                let _ = writeln!(out, "  end)");
179                let _ = write!(out, "end");
180                return Ok(out);
181            }
182            QueryCommand::Exec => {
183                let _ = writeln!(
184                    out,
185                    "@spec {}(pid(){}) :: :ok | {{:error, term()}}",
186                    func_name, param_specs
187                );
188            }
189            QueryCommand::ExecResult | QueryCommand::ExecRows => {
190                let _ = writeln!(
191                    out,
192                    "@spec {}(pid(){}) :: {{:ok, non_neg_integer()}} | {{:error, term()}}",
193                    func_name, param_specs
194                );
195            }
196        }
197        let _ = writeln!(out, "def {}(conn{}{}) do", func_name, sep, param_list);
198
199        match &analyzed.command {
200            QueryCommand::One => {
201                let _ = writeln!(
202                    out,
203                    "  case MyXQL.query(conn, \"{}\", {}) do",
204                    sql, param_args
205                );
206                let _ = writeln!(out, "    {{:ok, %MyXQL.Result{{rows: [row]}}}} ->");
207
208                let field_vars = columns
209                    .iter()
210                    .map(|c| c.field_name.clone())
211                    .collect::<Vec<_>>()
212                    .join(", ");
213                let _ = writeln!(out, "      [{}] = row", field_vars);
214
215                let struct_fields = columns
216                    .iter()
217                    .map(|c| format!("{}: {}", c.field_name, c.field_name))
218                    .collect::<Vec<_>>()
219                    .join(", ");
220                let _ = writeln!(out, "      {{:ok, %{}{{{}}}}}", struct_name, struct_fields);
221                let _ = writeln!(
222                    out,
223                    "    {{:ok, %MyXQL.Result{{rows: []}}}} -> {{:error, :not_found}}"
224                );
225                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
226                let _ = writeln!(out, "  end");
227            }
228            QueryCommand::Many => {
229                let _ = writeln!(
230                    out,
231                    "  case MyXQL.query(conn, \"{}\", {}) do",
232                    sql, param_args
233                );
234                let _ = writeln!(out, "    {{:ok, %MyXQL.Result{{rows: rows}}}} ->");
235
236                let field_vars = columns
237                    .iter()
238                    .map(|c| c.field_name.clone())
239                    .collect::<Vec<_>>()
240                    .join(", ");
241                let struct_fields = columns
242                    .iter()
243                    .map(|c| format!("{}: {}", c.field_name, c.field_name))
244                    .collect::<Vec<_>>()
245                    .join(", ");
246
247                let _ = writeln!(out, "      results = Enum.map(rows, fn row ->");
248                let _ = writeln!(out, "        [{}] = row", field_vars);
249                let _ = writeln!(out, "        %{}{{{}}}", struct_name, struct_fields);
250                let _ = writeln!(out, "      end)");
251                let _ = writeln!(out, "      {{:ok, results}}");
252                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
253                let _ = writeln!(out, "  end");
254            }
255            QueryCommand::Exec => {
256                let _ = writeln!(
257                    out,
258                    "  case MyXQL.query(conn, \"{}\", {}) do",
259                    sql, param_args
260                );
261                let _ = writeln!(out, "    {{:ok, _}} -> :ok");
262                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
263                let _ = writeln!(out, "  end");
264            }
265            QueryCommand::ExecResult | QueryCommand::ExecRows => {
266                let _ = writeln!(
267                    out,
268                    "  case MyXQL.query(conn, \"{}\", {}) do",
269                    sql, param_args
270                );
271                let _ = writeln!(
272                    out,
273                    "    {{:ok, %MyXQL.Result{{num_rows: n}}}} -> {{:ok, n}}"
274                );
275                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
276                let _ = writeln!(out, "  end");
277            }
278            QueryCommand::Batch => unreachable!(),
279        }
280
281        let _ = write!(out, "end");
282        Ok(out)
283    }
284
285    fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
286        let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
287        let mut out = String::new();
288        let _ = writeln!(out, "defmodule {} do", type_name);
289        let _ = writeln!(
290            out,
291            "  @moduledoc \"Enum type for {}.\"",
292            enum_info.sql_name
293        );
294        let _ = writeln!(out);
295        let _ = writeln!(out, "  @type t :: String.t()");
296        for value in &enum_info.values {
297            let variant = enum_variant_name(value, &self.manifest.naming);
298            let _ = writeln!(
299                out,
300                "  def {}(), do: \"{}\"",
301                to_snake_case(&variant),
302                value
303            );
304        }
305        // values/0 function
306        let values_list = enum_info
307            .values
308            .iter()
309            .map(|v| format!("\"{}\"", v))
310            .collect::<Vec<_>>()
311            .join(", ");
312        let _ = writeln!(out, "  def values, do: [{}]", values_list);
313        let _ = write!(out, "end");
314        Ok(out)
315    }
316
317    fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
318        let name = to_pascal_case(&composite.sql_name);
319        let mut out = String::new();
320        let _ = writeln!(out, "defmodule {} do", name);
321        let _ = writeln!(
322            out,
323            "  @moduledoc \"Composite type for {}.\"",
324            composite.sql_name
325        );
326        let _ = writeln!(out);
327        if composite.fields.is_empty() {
328            let _ = writeln!(out, "  defstruct []");
329        } else {
330            let fields = composite
331                .fields
332                .iter()
333                .map(|f| format!(":{}", to_snake_case(&f.name)))
334                .collect::<Vec<_>>()
335                .join(", ");
336            let _ = writeln!(out, "  defstruct [{}]", fields);
337        }
338        let _ = write!(out, "end");
339        Ok(out)
340    }
341}
scythe_codegen/backends/elixir_myxql.rs

scythe_codegen/backends/
elixir_myxql.rs
