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packages/db/src/sql.ts

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+/**
+ * SQL rendering shared by adapters and the migration runner. Column types are
+ * dialect-neutral in the model; this maps them to each dialect's SQL types and
+ * renders `CREATE TABLE`. (Postgres/MySQL land in later phases; the mappings are
+ * here so the model layer is already portable.)
+ */
+
+import type { ColumnDef, Model } from "./schema.ts";
+
+export type Dialect = "sqlite" | "postgres" | "mysql";
+
+function sqlType(def: ColumnDef, dialect: Dialect): string {
+  if (def.type === "id") {
+    if (dialect === "postgres") return "SERIAL";
+    if (dialect === "mysql") return "INT AUTO_INCREMENT";
+    return "INTEGER";
+  }
+  switch (def.type) {
+    case "int":
+      return "INTEGER";
+    case "real":
+      return dialect === "mysql" ? "DOUBLE" : "REAL";
+    case "bool":
+      return dialect === "postgres" ? "BOOLEAN" : "INTEGER";
+    case "timestamp":
+      return dialect === "sqlite" ? "TEXT" : "TIMESTAMP";
+    case "json":
+      return dialect === "postgres" ? "JSONB" : "TEXT";
+    default:
+      return dialect === "mysql" ? "VARCHAR(255)" : "TEXT";
+  }
+}
+
+function quoteId(id: string, dialect: Dialect): string {
+  return dialect === "mysql" ? `\`${id}\`` : `"${id}"`;
+}
+
+function renderDefault(value: unknown, dialect: Dialect): string {
+  if (value === "now") return "CURRENT_TIMESTAMP";
+  if (typeof value === "number") return String(value);
+  if (typeof value === "boolean") return dialect === "postgres" ? String(value) : value ? "1" : "0";
+  return `'${String(value).replace(/'/g, "''")}'`;
+}
+
+/** Render `CREATE TABLE` for a model in the given dialect. */
+export function createTableSql(model: Model, dialect: Dialect, ifNotExists = true): string {
+  const cols: string[] = [];
+  for (const [name, column] of Object.entries(model.columns)) {
+    const def = column.def;
+    const parts = [quoteId(name, dialect), sqlType(def, dialect)];
+    if (def.primaryKey) {
+      parts.push(
+        dialect === "sqlite" && def.type === "id" ? "PRIMARY KEY AUTOINCREMENT" : "PRIMARY KEY",
+      );
+    }
+    if (def.notNull && !def.primaryKey) parts.push("NOT NULL");
+    if (def.unique && !def.primaryKey) parts.push("UNIQUE");
+    if (def.default !== undefined) parts.push(`DEFAULT ${renderDefault(def.default, dialect)}`);
+    if (def.references) {
+      parts.push(
+        `REFERENCES ${quoteId(def.references.table, dialect)}(${quoteId(def.references.column, dialect)})`,
+      );
+    }
+    cols.push("  " + parts.join(" "));
+  }
+  const head = `CREATE TABLE ${ifNotExists ? "IF NOT EXISTS " : ""}${quoteId(model.name, dialect)}`;
+  return `${head} (\n${cols.join(",\n")}\n);`;
+}