Google Books Client 추가

ONMIR/Core/GoogleBooks/GoogleBooksClient.swift

@@ -0,0 +1,106 @@
+import Foundation
+
+public struct GoogleBooksClient: Sendable {
+  public enum GoogleBooksError: Error {
+    case invalidURL
+    case unexpectedResponse
+    case decodingError(Error)
+    case underlying(Error)
+  }
+
+  public enum OrderByType: String, Sendable {
+    case newest
+    case relevance
+  }
+
+  private let session: URLSession
+  private let baseURL = "https://www.googleapis.com/books/v1"
+
+  public init(session: URLSession = .shared) {
+    self.session = session
+  }
+
+  /// 책 검색
+  /// - Parameters:
+  ///   - query: 검색어
+  ///   - maxResults: 최대 결과 수 (기본값: 20)
+  /// - Returns: `BookSearchResponse`
+  public func searchBooks(
+    query: String,
+    startIndex: Int,
+    orderBy: OrderByType = .relevance,
+    maxResults: Int = 20
+  ) async throws(GoogleBooksError) -> BookSearchResponse {
+    var components = URLComponents(string: "\(baseURL)/volumes")
+    components?.queryItems = [
+      URLQueryItem(name: "q", value: query),
+      URLQueryItem(name: "startIndex", value: "\(startIndex)"),
+      URLQueryItem(name: "orderBy", value: orderBy.rawValue),
+      URLQueryItem(name: "maxResults", value: "\(maxResults)"),
+    ]
+
+    guard let url = components?.url else {
+      throw GoogleBooksError.invalidURL
+    }
+
+    do {
+      let (data, response) = try await session.data(from: url)
+
+      guard let httpResponse = response as? HTTPURLResponse,
+        (200...299).contains(httpResponse.statusCode)
+      else {
+        throw GoogleBooksError.unexpectedResponse
+      }
+
+      let decoder = JSONDecoder()
+      return try decoder.decode(BookSearchResponse.self, from: data)
+    } catch let decodingError as DecodingError {
+      throw GoogleBooksError.decodingError(decodingError)
+    } catch {
+      throw GoogleBooksError.underlying(error)
+    }
+  }
+}
+
+extension GoogleBooksClient {
+  public struct BookSearchResponse: Decodable, Sendable {
+    public let items: [BookItem]?
+    public let totalItems: Int
+    public let kind: String
+
+    public struct BookItem: Decodable, Sendable {
+      public var id: String
+      public let volumeInfo: VolumeInfo
+      public let saleInfo: SaleInfo?
+
+      public struct VolumeInfo: Decodable, Sendable {
+        public let title: String
+        public let subtitle: String?
+        public let authors: [String]?
+        public let publisher: String?
+        public let publishedDate: String?
+        public let description: String?
+        public let pageCount: Int?
+        public let categories: [String]?
+        public let language: String?
+        public let imageLinks: ImageLinks?
+
+        public struct ImageLinks: Decodable, Sendable {
+          public let smallThumbnail: String?
+          public let thumbnail: String?
+        }
+      }
+
+      public struct SaleInfo: Decodable, Sendable {
+        public let listPrice: Price?
+        public let retailPrice: Price?
+        public let buyLink: String?
+
+        public struct Price: Decodable, Sendable {
+          public let amount: Double?
+          public let currencyCode: String?
+        }
+      }
+    }
+  }
+}