cf: fail if any manual mod downloads are needed

src/main/java/me/itzg/helpers/curseforge/CurseForgeInstaller.java

@@ -20,7 +20,6 @@
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Schedulers;
 
-import java.io.BufferedWriter;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -91,6 +90,9 @@ public class CurseForgeInstaller {
         "worlds"
     ));
 
+    /**
+     * @throws MissingModsException if any mods need to be manually downloaded
+     */
     public void installFromModpackZip(Path modpackZip, String slug) throws IOException {
         requireNonNull(modpackZip, "modpackZip is required");
 
@@ -103,6 +105,9 @@ public void installFromModpackZip(Path modpackZip, String slug) throws IOExcepti
         });
     }
 
+    /**
+     * @throws MissingModsException if any mods need to be manually downloaded
+     */
     public void installFromModpackManifest(Path modpackManifestPath, String slug) throws IOException {
         requireNonNull(modpackManifestPath, "modpackManifest is required");
 
@@ -116,6 +121,9 @@ public void installFromModpackManifest(Path modpackManifestPath, String slug) th
         });
     }
 
+    /**
+     * @throws MissingModsException if any mods need to be manually downloaded
+     */
     public void install(String slug, String fileMatcher, Integer fileId) throws IOException {
 
         install(slug, context ->
@@ -188,6 +196,9 @@ private void installByRetrievingModpackZip(InstallContext context, String fileMa
         resolveModpackFileAndProcess(context, curseForgeMod, fileId, fileMatcher);
     }
 
+    /**
+     * @throws MissingModsException if any mods need to be manually downloaded
+     */
     private void processModpackManifest(InstallContext context,
         MinecraftModpackManifest modpackManifest, OverridesApplier overridesApplier
     ) throws IOException {
@@ -241,6 +252,9 @@ private int hashModpackFileReferences(List<ManifestFileRef> files) {
         return hash;
     }
 
+    /**
+     * @throws MissingModsException if any mods need to be manually downloaded
+     */
     private void resolveModpackFileAndProcess(
         InstallContext context,
         CurseForgeMod mod, Integer fileId,
@@ -376,6 +390,9 @@ private void finalizeExistingInstallation(CurseForgeManifest prevManifest) throw
         }
     }
 
+    /**
+     * @throws MissingModsException if any mods need to be manually downloaded
+     */
     private void finalizeResults(InstallContext context, ModPackResults results, int modId, int fileId, String displayName) throws IOException {
         final CurseForgeManifest newManifest = CurseForgeManifest.builder()
             .modpackName(results.getName())
@@ -394,21 +411,8 @@ private void finalizeResults(InstallContext context, ModPackResults results, int
 
         Manifests.save(outputDir, CURSEFORGE_ID, newManifest);
 
-        final Path needsDownloadFile = outputDir.resolve("MODS_NEED_DOWNLOAD.txt");
         if (!results.getNeedsDownload().isEmpty()) {
-            try (BufferedWriter writer = Files.newBufferedWriter(needsDownloadFile)) {
-                for (PathWithInfo info : results.getNeedsDownload()) {
-                    writer.write(String.format("%s :: \"%s\" FROM %s",
-                        info.getModInfo().getName(),
-                        info.getCurseForgeFile().getDisplayName(),
-                        info.getModInfo().getLinks().getWebsiteUrl()
-                        ));
-                    writer.newLine();
-                }
-            }
-        }
-        else {
-            Files.deleteIfExists(needsDownloadFile);
+            throw new MissingModsException(results.getNeedsDownload());
         }
 
         if (resultsFile != null) {

src/main/java/me/itzg/helpers/curseforge/InstallCurseForgeCommand.java

@@ -1,16 +1,7 @@
 package me.itzg.helpers.curseforge;
 
-import static me.itzg.helpers.http.Fetch.fetch;
-
-import java.io.IOException;
-import java.nio.file.Path;
-import java.util.Set;
-import java.util.concurrent.Callable;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-import java.util.stream.Collectors;
-import java.util.stream.Stream;
 import me.itzg.helpers.files.ResultsFileWriter;
+import me.itzg.helpers.files.TabularOutput;
 import me.itzg.helpers.http.PathOrUri;
 import me.itzg.helpers.http.PathOrUriConverter;
 import me.itzg.helpers.http.SharedFetchArgs;
@@ -20,6 +11,20 @@
 import picocli.CommandLine.ExitCode;
 import picocli.CommandLine.Option;
 
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Set;
+import java.util.concurrent.Callable;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static me.itzg.helpers.http.Fetch.fetch;
+
 @Command(name = "install-curseforge", subcommands = {
     SchemasCommand.class
 })
@@ -132,6 +137,9 @@ static class Listed {
     @ArgGroup(exclusive = false)
     SharedFetchArgs sharedFetchArgs = new SharedFetchArgs();
 
+    @Option(names = "--missing-mods-filename", defaultValue = "MODS_NEED_DOWNLOAD.txt")
+    String missingModsFilename;
+
     private static final Pattern PAGE_URL_PATTERN = Pattern.compile(
         "https://(www|beta)\\.curseforge\\.com/minecraft/modpacks/(?<slug>.+?)(/files(/(?<fileId>\\d+)?)?)?");
 
@@ -181,15 +189,54 @@ public Integer call() throws Exception {
             installer.setApiBaseUrl(apiBaseUrl);
         }
 
-        if (modpackZip != null) {
-            installer.installFromModpackZip(modpackZip, slug);
-        } else if (modpackManifest != null) {
-            installer.installFromModpackManifest(modpackManifest, slug);
-        } else {
-            installer.install(slug, filenameMatcher, fileId);
+        final Path needsDownloadFile = missingModsFilename != null && !missingModsFilename.isEmpty() ?
+            outputDirectory.resolve(missingModsFilename)
+            : null;
+
+        try {
+            if (modpackZip != null) {
+                installer.installFromModpackZip(modpackZip, slug);
+            } else if (modpackManifest != null) {
+                installer.installFromModpackManifest(modpackManifest, slug);
+            } else {
+                installer.install(slug, filenameMatcher, fileId);
+            }
+            if (needsDownloadFile != null) {
+                Files.deleteIfExists(needsDownloadFile);
+            }
+
+            return ExitCode.OK;
+        } catch (MissingModsException e) {
+
+            final TabularOutput tabOut = new TabularOutput('=', "  ", "Mod", "Slug", "Filename", "Download page");
+            for (PathWithInfo info : e.getNeedsDownload()) {
+                tabOut.addRow(
+                    info.getModInfo().getName(),
+                    info.getModInfo().getSlug(),
+                    info.getCurseForgeFile().getDisplayName(),
+                    info.getModInfo().getLinks().getWebsiteUrl()
+                );
+            }
+
+            if (needsDownloadFile != null) {
+                try (BufferedWriter writer = Files.newBufferedWriter(needsDownloadFile)) {
+                    tabOut.output(new PrintWriter(writer));
+                }
+            }
+
+            System.err.println();
+            System.err.println("Missing mods need to be manually downloaded into repo or excluded:");
+            if (needsDownloadFile != null) {
+                System.err.printf("(Also written to %s%n", needsDownloadFile);
+            }
+            System.err.println();
+            final PrintWriter out = new PrintWriter(System.err);
+            tabOut.output(out);
+            out.close();
+
+            return ExitCode.USAGE;
         }
 
-        return ExitCode.OK;
     }
 
     private ExcludeIncludesContent loadExcludeIncludes() throws IOException {

src/main/java/me/itzg/helpers/curseforge/MissingModsException.java

@@ -0,0 +1,15 @@
+package me.itzg.helpers.curseforge;
+
+import lombok.Getter;
+
+import java.util.List;
+
+public class MissingModsException extends RuntimeException {
+    @Getter
+    private final List<PathWithInfo> needsDownload;
+
+    public MissingModsException(List<PathWithInfo> needsDownload) {
+
+        this.needsDownload = needsDownload;
+    }
+}

src/main/java/me/itzg/helpers/files/TabularOutput.java

@@ -0,0 +1,63 @@
+package me.itzg.helpers.files;
+
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.List;
+
+public class TabularOutput {
+    private final char headerDivider;
+    private final String columnDivider;
+    private final String[] headers;
+    private final List<String[]> rows = new ArrayList<>();
+    private final int[] widths;
+
+    public TabularOutput(char headerDivider, String columnDivider, String... headers) {
+        this.headerDivider = headerDivider;
+        this.columnDivider = columnDivider;
+        this.headers = headers;
+        this.widths = new int[headers.length];
+        for (int i = 0; i < headers.length; i++) {
+            widths[i] = headers[i].length();
+        }
+    }
+
+    public void addRow(String... cells) {
+        if (cells.length != headers.length) {
+            throw new IllegalArgumentException(String.format("Row has %d columns but header has %d", cells.length, headers.length));
+        }
+
+        rows.add(cells);
+
+        for (int i = 0; i < cells.length; i++) {
+            widths[i] = Math.max(widths[i], cells[i].length());
+        }
+    }
+
+    public void output(PrintWriter out) {
+        final StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < widths.length; i++) {
+            sb.append("%-").append(widths[i]).append("s");
+            if (i < widths.length - 1) {
+                sb.append(columnDivider);
+            }
+        }
+        sb.append("%n");
+        final String format = sb.toString();
+
+        out.printf(format, (Object[]) headers);
+
+        for (int i = 0; i < widths.length; i++) {
+            for (int j = 0; j < widths[i]; j++) {
+                out.print(headerDivider);
+            }
+            if (i < widths.length - 1) {
+                out.print(columnDivider);
+            }
+        }
+        out.println();
+
+        for (String[] row : rows) {
+            out.printf(format, (Object[]) row);
+        }
+    }
+}