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 type_ref = if c.neutral_type.starts_with("enum::") {
73                format!("{}.t()", c.full_type)
74            } else {
75                c.full_type.clone()
76            };
77            let _ = writeln!(out, "    {}: {}{}", c.field_name, type_ref, sep);
78        }
79        let _ = writeln!(out, "  }}");
80
81        // Generate defstruct
82        let fields = columns
83            .iter()
84            .map(|c| format!(":{}", c.field_name))
85            .collect::<Vec<_>>()
86            .join(", ");
87        let _ = writeln!(out, "  defstruct [{}]", fields);
88        let _ = write!(out, "end");
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_with_optional(
110            &analyzed.sql,
111            &analyzed.optional_params,
112            &analyzed.params,
113        );
114        let mut out = String::new();
115
116        // Parameter list
117        let param_list = params
118            .iter()
119            .map(|p| p.field_name.clone())
120            .collect::<Vec<_>>()
121            .join(", ");
122        let sep = if param_list.is_empty() { "" } else { ", " };
123
124        // Build the params list for MyXQL.query
125        let param_args = if params.is_empty() {
126            "[]".to_string()
127        } else {
128            format!(
129                "[{}]",
130                params
131                    .iter()
132                    .map(|p| p.field_name.clone())
133                    .collect::<Vec<_>>()
134                    .join(", ")
135            )
136        };
137
138        // Build @spec
139        let param_specs = if params.is_empty() {
140            String::new()
141        } else {
142            let specs: Vec<String> = params.iter().map(|p| p.full_type.clone()).collect();
143            format!(", {}", specs.join(", "))
144        };
145        match &analyzed.command {
146            QueryCommand::One => {
147                let _ = writeln!(
148                    out,
149                    "@spec {}(MyXQL.conn(){}) :: {{:ok, %{}{{}}}} | {{:error, term()}}",
150                    func_name, param_specs, struct_name
151                );
152            }
153            QueryCommand::Many => {
154                let _ = writeln!(
155                    out,
156                    "@spec {}(MyXQL.conn(){}) :: {{:ok, [%{}{{}}]}} | {{:error, term()}}",
157                    func_name, param_specs, struct_name
158                );
159            }
160            QueryCommand::Batch => {
161                let batch_fn_name = format!("{}_batch", func_name);
162                let _ = writeln!(
163                    out,
164                    "@spec {}(MyXQL.conn(), list()) :: :ok | {{:error, term()}}",
165                    batch_fn_name
166                );
167                let _ = writeln!(out, "def {}(conn, items) do", batch_fn_name);
168                let _ = writeln!(out, "  Enum.reduce_while(items, :ok, fn item, :ok ->");
169                if params.len() > 1 {
170                    let _ = writeln!(
171                        out,
172                        "    case MyXQL.query(conn, \"{}\", Tuple.to_list(item)) do",
173                        sql
174                    );
175                } else if params.len() == 1 {
176                    let _ = writeln!(out, "    case MyXQL.query(conn, \"{}\", [item]) do", sql);
177                } else {
178                    let _ = writeln!(out, "    case MyXQL.query(conn, \"{}\", []) do", sql);
179                }
180                let _ = writeln!(out, "      {{:ok, _}} -> {{:cont, :ok}}");
181                let _ = writeln!(out, "      {{:error, err}} -> {{:halt, {{:error, err}}}}");
182                let _ = writeln!(out, "    end");
183                let _ = writeln!(out, "  end)");
184                let _ = write!(out, "end");
185                return Ok(out);
186            }
187            QueryCommand::Exec => {
188                let _ = writeln!(
189                    out,
190                    "@spec {}(MyXQL.conn(){}) :: :ok | {{:error, term()}}",
191                    func_name, param_specs
192                );
193            }
194            QueryCommand::ExecResult | QueryCommand::ExecRows => {
195                let _ = writeln!(
196                    out,
197                    "@spec {}(MyXQL.conn(){}) :: {{:ok, non_neg_integer()}} | {{:error, term()}}",
198                    func_name, param_specs
199                );
200            }
201            QueryCommand::Grouped => {
202                unreachable!("Grouped is rewritten to Many before codegen")
203            }
204        }
205        let _ = writeln!(out, "def {}(conn{}{}) do", func_name, sep, param_list);
206
207        match &analyzed.command {
208            QueryCommand::One => {
209                let _ = writeln!(
210                    out,
211                    "  case MyXQL.query(conn, \"{}\", {}) do",
212                    sql, param_args
213                );
214                let _ = writeln!(out, "    {{:ok, %MyXQL.Result{{rows: [row]}}}} ->");
215
216                let field_vars = columns
217                    .iter()
218                    .map(|c| c.field_name.clone())
219                    .collect::<Vec<_>>()
220                    .join(", ");
221                let _ = writeln!(out, "      [{}] = row", field_vars);
222
223                let struct_fields = columns
224                    .iter()
225                    .map(|c| format!("{}: {}", c.field_name, c.field_name))
226                    .collect::<Vec<_>>()
227                    .join(", ");
228                let _ = writeln!(out, "      {{:ok, %{}{{{}}}}}", struct_name, struct_fields);
229                let _ = writeln!(
230                    out,
231                    "    {{:ok, %MyXQL.Result{{rows: []}}}} -> {{:error, :not_found}}"
232                );
233                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
234                let _ = writeln!(out, "  end");
235            }
236            QueryCommand::Many => {
237                let _ = writeln!(
238                    out,
239                    "  case MyXQL.query(conn, \"{}\", {}) do",
240                    sql, param_args
241                );
242                let _ = writeln!(out, "    {{:ok, %MyXQL.Result{{rows: rows}}}} ->");
243
244                let field_vars = columns
245                    .iter()
246                    .map(|c| c.field_name.clone())
247                    .collect::<Vec<_>>()
248                    .join(", ");
249                let struct_fields = columns
250                    .iter()
251                    .map(|c| format!("{}: {}", c.field_name, c.field_name))
252                    .collect::<Vec<_>>()
253                    .join(", ");
254
255                let _ = writeln!(out, "      results = Enum.map(rows, fn row ->");
256                let _ = writeln!(out, "        [{}] = row", field_vars);
257                let _ = writeln!(out, "        %{}{{{}}}", struct_name, struct_fields);
258                let _ = writeln!(out, "      end)");
259                let _ = writeln!(out, "      {{:ok, results}}");
260                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
261                let _ = writeln!(out, "  end");
262            }
263            QueryCommand::Exec => {
264                let _ = writeln!(
265                    out,
266                    "  case MyXQL.query(conn, \"{}\", {}) do",
267                    sql, param_args
268                );
269                let _ = writeln!(out, "    {{:ok, _}} -> :ok");
270                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
271                let _ = writeln!(out, "  end");
272            }
273            QueryCommand::ExecResult | QueryCommand::ExecRows => {
274                let _ = writeln!(
275                    out,
276                    "  case MyXQL.query(conn, \"{}\", {}) do",
277                    sql, param_args
278                );
279                let _ = writeln!(
280                    out,
281                    "    {{:ok, %MyXQL.Result{{num_rows: n}}}} -> {{:ok, n}}"
282                );
283                let _ = writeln!(out, "    {{:error, err}} -> {{:error, err}}");
284                let _ = writeln!(out, "  end");
285            }
286            QueryCommand::Batch | QueryCommand::Grouped => unreachable!(),
287        }
288
289        let _ = write!(out, "end");
290        Ok(out)
291    }
292
293    fn generate_enum_def(&self, enum_info: &EnumInfo) -> Result<String, ScytheError> {
294        let type_name = enum_type_name(&enum_info.sql_name, &self.manifest.naming);
295        let mut out = String::new();
296        let _ = writeln!(out, "defmodule {} do", type_name);
297        let _ = writeln!(
298            out,
299            "  @moduledoc \"Enum type for {}.\"",
300            enum_info.sql_name
301        );
302        let _ = writeln!(out);
303        let _ = writeln!(out, "  @type t :: String.t()");
304        let _ = writeln!(out);
305        for value in &enum_info.values {
306            let variant = enum_variant_name(value, &self.manifest.naming);
307            let _ = writeln!(out, "  @spec {}() :: String.t()", to_snake_case(&variant));
308            let _ = writeln!(
309                out,
310                "  def {}(), do: \"{}\"",
311                to_snake_case(&variant),
312                value
313            );
314        }
315        // values/0 function
316        let values_list = enum_info
317            .values
318            .iter()
319            .map(|v| format!("\"{}\"", v))
320            .collect::<Vec<_>>()
321            .join(", ");
322        let _ = writeln!(out, "  @spec values() :: [String.t()]");
323        let _ = writeln!(out, "  def values, do: [{}]", values_list);
324        let _ = write!(out, "end");
325        Ok(out)
326    }
327
328    fn generate_composite_def(&self, composite: &CompositeInfo) -> Result<String, ScytheError> {
329        let name = to_pascal_case(&composite.sql_name);
330        let mut out = String::new();
331        let _ = writeln!(out, "defmodule {} do", name);
332        let _ = writeln!(
333            out,
334            "  @moduledoc \"Composite type for {}.\"",
335            composite.sql_name
336        );
337        let _ = writeln!(out);
338        // Generate @type definition
339        if composite.fields.is_empty() {
340            let _ = writeln!(out, "  @type t :: %__MODULE__{{}}");
341        } else {
342            let _ = writeln!(out, "  @type t :: %__MODULE__{{");
343            for (i, f) in composite.fields.iter().enumerate() {
344                let sep = if i + 1 < composite.fields.len() {
345                    ","
346                } else {
347                    ""
348                };
349                let _ = writeln!(out, "    {}: term(){}", to_snake_case(&f.name), sep);
350            }
351            let _ = writeln!(out, "  }}");
352        }
353        let _ = writeln!(out);
354        if composite.fields.is_empty() {
355            let _ = writeln!(out, "  defstruct []");
356        } else {
357            let fields = composite
358                .fields
359                .iter()
360                .map(|f| format!(":{}", to_snake_case(&f.name)))
361                .collect::<Vec<_>>()
362                .join(", ");
363            let _ = writeln!(out, "  defstruct [{}]", fields);
364        }
365        let _ = write!(out, "end");
366        Ok(out)
367    }
368}
scythe_codegen/backends/elixir_myxql.rs

scythe_codegen/backends/
elixir_myxql.rs
