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.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;
import java.util.HashMap;
import java.util.Map;

public class MovieService {

    private final static String GENRES_URL = "https://api.meshcomp.ir/api/v1/genres";
    private final static HttpClient client = HttpClient.newHttpClient();

    private Map<Long, Movie> moviesCache = new HashMap<>();
    private boolean isMoviesLoaded = false;
    private int totalMovies = 0;
    private int totalPages = 0;

    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());
        }
    }


    /**
     * TODO 1: 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) {
        // TODO: Write your code here
        // All parsing code must be inside try-catch
        try {
            // Your code here

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


    /**
     * TODO 2: Load all movies into cache (called automatically when needed)
     *
     * Steps:
     * - if (isMoviesLoaded) return; (already loaded)
     * - Clear moviesCache
     * - Get first page of genre 2 (Drama) to find total_pages
     * - Loop through all pages (1 to total_pages)
     * - For each page, get "movies" array
     * - Extract: id, title, year, poster, genres array
     * - For genres, loop and convert each string to Genre object
     * - Store in moviesCache using id as key
     * - Set isMoviesLoaded = true
     *
     * PUT ALL PARSING CODE INSIDE try-catch
     */
    private void loadAllMovies() {
        // TODO: Write your code here
        // All parsing code must be inside try-catch
        try {
            // Your code here

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


    /**
     * TODO 3: Display all movies with pagination
     *
     * Steps:
     * - Call loadAllMovies() first
     * - Calculate total pages: (totalMovies + 9) / 10
     * - Validate page number (1 to totalPages)
     * - Calculate start and end index
     * - Convert moviesCache.values() to List
     * - Loop from start to end and display: "ID: {id} | {title} ({year})"
     *
     * loadAllMovies() already has try-catch inside
     */
    public void displayAllMovies(int page) {
        // TODO: Write your code here
        // loadAllMovies() already has try-catch
        // Your display logic here
    }


    /**
     * TODO 4 (BONUS): Display movie details by ID
     *
     * Steps:
     * - Call loadAllMovies() first
     * - Get movie from moviesCache using movieId
     * - If movie is null, print "Movie not found"
     * - Otherwise print: ID, Title, Year, Genres, Poster
     *
     * loadAllMovies() already has try-catch inside
     */
    public void displayMovieDetails(Long movieId) {
        // TODO: Write your code here (BONUS)
        // loadAllMovies() already has try-catch
        // Your display logic here
    }

    private String getGenresString(List<Genre> genres) {
        if (genres == null || genres.isEmpty()) {
            return "No genres";
        }
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < genres.size(); i++) {
            sb.append(genres.get(i).getName());
            if (i < genres.size() - 1) {
                sb.append(", ");
            }
        }
        return sb.toString();
    }

    public int getTotalMovies() {
        return totalMovies;
    }
}