HW-03-oop-and-api/src/main/java/movie/apis/MovieService.java

package movie.apis;

import com.google.gson.*;
import com.google.gson.reflect.TypeToken;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.lang.reflect.Type;
import java.util.ArrayList;
import java.util.List;

public class MovieService
{
    private final static String GENRES_URL = "https://api.meshcomp.ir/api/v1/genres";
    private final static String MOVIE_BY_ID_URL = "https://api.meshcomp.ir/api/v1/movies/";
    private final static HttpClient client = HttpClient.newHttpClient();

    private String getGenresList()
    {
        try
        {
            HttpRequest request = HttpRequest.newBuilder().uri(URI.create(GENRES_URL)).build();

            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

            if (response.statusCode() == 200)
            {
                System.out.println("Genres List received successfully");
                return response.body();
            }
            else
                throw new IOException("HTTP error code: " + response.statusCode());
        }
        catch (Exception e)
        {
            System.out.println("!!Exception : " + e.getMessage());
        }

        return null;
    }

    private String getMoviesByGenreList(Long genreId, Long page)
    {
        try
        {
            String url = "https://api.meshcomp.ir/api/v1/genres/" + genreId + "/movies?page=" + page;

            HttpRequest request = HttpRequest.newBuilder().uri(URI.create(url)).build();

            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

            if (response.statusCode() == 200)
                return response.body();
            else
            {
                System.out.println("HTTP error code: " + response.statusCode());
                return null;
            }
        }
        catch (Exception e)
        {
            System.out.println("!!Exception : " + e.getMessage());
        }

        return null;
    }

    public void displayGenres()
    {
        String jsonResponse = getGenresList();

        if (jsonResponse == null)
        {
            System.out.println("Failed to get genres");
            return;
        }

        try
        {
            JsonObject rootObject = JsonParser.parseString(jsonResponse).getAsJsonObject();
            JsonArray genresArray = rootObject.getAsJsonArray("genres");
            Type genreListType = new TypeToken<ArrayList<Genre>>(){}.getType();
            Gson gson = new Gson();
            List<Genre> genres = gson.fromJson(genresArray, genreListType);

            System.out.println("\nALL GENRES:");
            for (Genre genre : genres)
                System.out.println(genre.getId() + ". " + genre.getName());

            System.out.println();
        }
        catch (Exception e)
        {
            System.err.println("ERROR parsing genres: " + e.getMessage());
        }
    }

    /**
     * Display movies for a specific genre and page
     *
     * JSON format: { "movies": [ { "id": 1, "title": "Movie", "year": "1994" } ], "total": 177, "total_pages": 18 }
     *
     * Steps:
     * - Call getMoviesByGenreList(genreId, page) to get JSON
     * - Parse JSON to JsonObject
     * - Get "movies" array (NOT "data")
     * - Loop through array and print: "ID: {id} | {title} ({year})"
     * - Also print total and total_pages
     *
     * PUT ALL PARSING CODE INSIDE try-catch
     */
    public void displayMoviesByGenre(Long genreId, Long page)
    {
        try
        {
            String RawData = getMoviesByGenreList(genreId, page);
            if (RawData == null)
                throw new IllegalArgumentException("Invalid genreId or page number; no data found");

            JsonObject JsonData = JsonParser.parseString(RawData).getAsJsonObject();
            JsonArray MoviesArray = JsonData.getAsJsonArray("movies");
            Type MovieListType = new TypeToken<ArrayList<Movie>>(){}.getType();
            Gson GsonHandle = new Gson();
            List<Movie> Movies = GsonHandle.fromJson(MoviesArray, MovieListType);

            System.out.printf("\nMovies with %s genre:\n", JsonData.getAsJsonObject("genre").get("name").getAsString());
            for (Movie CurrentMovie : Movies)
                System.out.printf("ID: %d | %s (%s)\n", CurrentMovie.getId(), CurrentMovie.getTitle(), CurrentMovie.getYear());

            System.out.printf("\nTotal: %s - Total pages: %s", JsonData.get("total").getAsString(), JsonData.get("total_pages").getAsString());

            System.out.println();
        }
        catch (Exception e)
        {
            System.err.println("ERROR: " + e.getMessage());
        }
    }


    /**
     * BONUS: Fetch movie details from API using movie ID
     * URL format: https://api.meshcomp.ir/api/v1/movies/{movieId}
     */
    private String getMovieById(Long movieId)
    {
        try
        {
            final String URL = MOVIE_BY_ID_URL + movieId;

            HttpRequest Request = HttpRequest.newBuilder().uri(URI.create(URL)).build();
            HttpResponse<String> Respone = client.send(Request, HttpResponse.BodyHandlers.ofString());

            if (Respone.statusCode() == HttpURLConnection.HTTP_OK)
                return Respone.body();

            return null;
        }
        catch (Exception e)
        {
            System.out.println("!!Exception : " + e.getMessage());
        }

        return null;
    }
    
    /**
     * BONUS TODO: Display complete movie details for a given movie ID
     *
     * Expected JSON format from getMovieById():
     * {
     *   "id": 1,
     *   "title": "The Shawshank Redemption",
     *   "year": "1994",
     *   "genres": ["Crime", "Drama"],
     *   "poster": "https://moviesapi.ir/images/tt0111161_poster.jpg",
     *   "country": "USA",
     *   "imdb_rating": "9.3"
     * }
     *
     * INSTRUCTIONS:
     * 1. Call getMovieById(movieId) to get the JSON response
     * 2. Check if response is null (if yes, print error and return)
     * 3. Parse the JSON string to JsonObject (inside try-catch)
     * 4. Extract all fields: id, title, year, genres array, poster, country, imdb_rating
     * 5. Convert genres array to comma-separated string
     * 6. Print all movie details in a readable format
     *
     * PUT ALL PARSING CODE INSIDE THE EXISTING try-catch
     *
     * @param movieId The ID of the movie to display
     */
    public void displayMovieDetails(Long movieId)
    {
        String jsonResponse = getMovieById(movieId);

        if (jsonResponse == null)
        {
            System.out.println("Failed to get movie details for ID: " + movieId);
            return;
        }

        try
        {
            JsonObject JsonData = JsonParser.parseString(jsonResponse).getAsJsonObject();

            Gson GsonHandle = new Gson();
            Type MovieType = new TypeToken<Movie>(){}.getType();
            Movie RequestedMovie = GsonHandle.fromJson(JsonData, MovieType);

            System.out.println();
            System.out.println(RequestedMovie);
        }
        catch (Exception e)
        {
            System.err.println("ERROR parsing movie details: " + e.getMessage());
        }
    }
}