import type {
  Schema,
  ReferenceSchema,
  ReverseReferenceSchema,
  UnionSchema,
} from "./types";

export function schemaToTypeString(
  schema: Schema,
  resourceNames?: Map<string, string>,
): string {
  switch (schema.type) {
    case "string":
      return "string";
    case "number":
    case "int":
    case "float":
      return "number";
    case "boolean":
      return "boolean";
    case "stringLiteral":
      return `"${schema.value}"`;
    case "union":
      return schema.members
        .map((m) => schemaToTypeString(m, resourceNames))
        .join(" | ");
    case "reference": {
      const typeName =
        resourceNames?.get(schema.tableName) ||
        schema.tableName.charAt(0).toUpperCase() + schema.tableName.slice(1);
      const baseType = schema.isArray ? `${typeName}[]` : typeName;
      return schema.isOptional ? `${baseType} | null` : baseType;
    }
    case "reverseReference": {
      const typeName =
        resourceNames?.get(schema.tableName) ||
        schema.tableName.charAt(0).toUpperCase() + schema.tableName.slice(1);
      const baseType = `${typeName}[]`;
      return schema.isOptional ? `${baseType} | null` : baseType;
    }
    case "array":
      if (schema.element.type === "tuple") {
        const tupleElements = schema.element.elements.map((el) => {
          const typeStr = schemaToTypeString(el.schema, resourceNames);
          return el.name ? `${el.name}: ${typeStr}` : typeStr;
        });
        return `[${tupleElements.join(", ")}][]`;
      }
      const elementType = schemaToTypeString(schema.element, resourceNames);
      if (schema.element.type === "union") {
        return `(${elementType})[]`;
      }
      return `${elementType}[]`;
    case "tuple":
      const tupleElements = schema.elements.map((el) => {
        const typeStr = schemaToTypeString(el.schema, resourceNames);
        return el.name ? `${el.name}: ${typeStr}` : typeStr;
      });
      return `[${tupleElements.join(", ")}]`;
    default:
      return "unknown";
  }
}

export function createValidator(schema: Schema): (value: unknown) => boolean {
  return function validate(value: unknown): boolean {
    switch (schema.type) {
      case "string":
        return typeof value === "string";
      case "number":
        return typeof value === "number" && !isNaN(value);
      case "int":
        return (
          typeof value === "number" && !isNaN(value) && Number.isInteger(value)
        );
      case "float":
        return typeof value === "number" && !isNaN(value);
      case "boolean":
        return typeof value === "boolean";
      case "stringLiteral":
        return typeof value === "string" && value === schema.value;
      case "union":
        return schema.members.some((member) => createValidator(member)(value));
      case "tuple":
        if (!Array.isArray(value)) return false;
        if (value.length !== schema.elements.length) return false;
        return schema.elements.every((elementSchema, index) =>
          createValidator(elementSchema.schema)(value[index]),
        );
      case "array":
        if (!Array.isArray(value)) return false;
        return value.every((item) => createValidator(schema.element)(item));
      case "reference":
        if (schema.isOptional && value === null) return true;
        if (schema.isArray) {
          return (
            Array.isArray(value) && value.every((id) => typeof id === "string")
          );
        }
        return (
          typeof value === "string" ||
          (Array.isArray(value) && value.every((id) => typeof id === "string"))
        );
      case "reverseReference":
        if (schema.isOptional && value === null) return true;
        return Array.isArray(value);
      default:
        return false;
    }
  };
}