add web app & add concurrency

Justfile

@@ -0,0 +1,3 @@
+dev:
+  cd web && pnpm run build
+  go run .

main.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"embed"
 	"encoding/json"
 	"fmt"
 	"io"
@@ -11,6 +12,7 @@ import (
 	"path"
 	"strconv"
 	"sync"
+	"time"
 
 	"go.senan.xyz/taglib"
 )
@@ -23,6 +25,40 @@ func sendJSON(w http.ResponseWriter, data any, status int) {
 	}
 }
 
+func sendError(w http.ResponseWriter, msg string, err error, status int) {
+	m := msg
+	if err != nil {
+		m = fmt.Sprintf("%s: %v", msg, err)
+	}
+	sendJSON(w, struct {
+		Error string `json:"error"`
+	}{
+		Error: m,
+	}, status)
+}
+
+//go:embed web/dist/*
+var webDist embed.FS
+
+type DownloadStatus = string
+
+var (
+	DownloadStatusAdded      = "ADDED"
+	DownloadStatusInProgress = "IN_PROGRESS"
+	DownloadStatusCompleted  = "COMPLETED"
+)
+
+type DownloadItem struct {
+	sync.Mutex
+
+	Status         DownloadStatus
+	Album          monochrome.AlbumInfo
+	InstalledFiles int
+	TotalFiles     int
+}
+
+var downloads = map[int]*DownloadItem{}
+
 func main() {
 	mClient := monochrome.NewClient(monochrome.ClientConfig{
 		ApiURL: "https://api.monochrome.tf",
@@ -30,134 +66,189 @@ func main() {
 
 	mux := http.NewServeMux()
 
+	mux.HandleFunc("GET /", func(w http.ResponseWriter, r *http.Request) {
+		path := r.URL.Path
+		if path == "/" {
+			path = "/index.html"
+		}
+		filePath := "web/dist" + path
+		http.ServeFileFS(w, r, webDist, filePath)
+	})
+
 	mux.HandleFunc("GET /search", func(w http.ResponseWriter, r *http.Request) {
 		q := r.URL.Query().Get("q")
 
 		results, err := mClient.SearchAlbum(q)
 		if err != nil {
-			http.Error(w, err.Error(), 404)
+			sendError(w, "failed to find albums", err, 404)
 			return
 		}
 
 		sendJSON(w, results, 200)
 	})
 
+	mux.HandleFunc("GET /cover/{id}", func(w http.ResponseWriter, r *http.Request) {
+		coverImg, err := mClient.AlbumCoverImage(r.PathValue("id"))
+		if err != nil {
+			sendError(w, "failed to download album cover", err, 500)
+			return
+		}
+
+		w.Header().Set("Content-Type", "image/jpeg")
+		w.WriteHeader(200)
+		if _, err := w.Write(coverImg); err != nil {
+			sendError(w, "failed to send response", err, 500)
+			return
+		}
+	})
+
+	mux.HandleFunc("GET /downloads", func(w http.ResponseWriter, r *http.Request) {
+		type item struct {
+			ID             int                  `json:"id"`
+			Album          monochrome.AlbumInfo `json:"album"`
+			InstalledFiles int                  `json:"installedFiles"`
+			TotalFiles     int                  `json:"totalFiles"`
+		}
+		items := []item{}
+		for id, download := range downloads {
+			items = append(items, item{
+				ID:             id,
+				Album:          download.Album,
+				InstalledFiles: download.InstalledFiles,
+				TotalFiles:     download.TotalFiles,
+			})
+		}
+		sendJSON(w, items, 200)
+	})
+
 	mux.HandleFunc("GET /download-album/{id}", func(w http.ResponseWriter, r *http.Request) {
 		id, err := strconv.Atoi(r.PathValue("id"))
 		if err != nil {
-			http.Error(w, err.Error(), 500)
+			sendError(w, "failed to parse id from request url", err, 500)
 			return
 		}
 
 		album, err := mClient.AlbumInfo(id)
 		if err != nil {
-			http.Error(w, err.Error(), 404)
+			sendError(w, "failed to get album info", err, 500)
 			return
 		}
 
 		if album == nil {
-			http.Error(w, "album not found for some reason", 404)
+			sendError(w, "album not found", nil, 404)
 			return
 		}
 
-		albumCoverImg, err := mClient.AlbumCoverImage(album.CoverID)
-		if err != nil {
-			log.Printf("failed to download album cover: %v\n", err)
+		downloads[album.ID] = &DownloadItem{
+			Status:         DownloadStatusAdded,
+			Album:          *album,
+			InstalledFiles: 0,
+			TotalFiles:     album.NumberOfTracks,
 		}
 
-		if err := os.Mkdir("./Music/"+album.Title, 0777); err != nil {
-			http.Error(w, fmt.Sprintf("failed to create album directory: %v", err), 500)
-			return
-		}
-
-		type Response struct {
-			sync.Mutex
-			count int
-		}
-		response := new(Response)
-
-		var wg sync.WaitGroup
-		for _, track := range album.Items {
-			wg.Go(func() {
-				info, err := mClient.TrackInfo(track.Item.ID, track.Item.AudioQuality)
-				if err != nil {
-					log.Printf("failed to get track info: %v\n", err)
-					return
-				}
-
-				manifest, err := mClient.DecodeManifest(info.Manifest)
-				if err != nil {
-					log.Printf("failed to decode track manifest: %v\n", err)
-					return
-				}
-
-				if manifest.EncryptionType != monochrome.TrackManifestEncryptionNone {
-					log.Println("file is encrypted; can't download")
-					return
-				}
-
-				if len(manifest.URLs) == 0 {
-					log.Println("track manifest doesn't have urls array")
-					return
-				}
-
-				resp, err := http.Get(manifest.URLs[0])
-				if err != nil {
-					log.Printf("failed to download track data: %v\n", err)
-					return
-				}
-				defer resp.Body.Close()
-
-				data, err := io.ReadAll(resp.Body)
-				if err != nil {
-					log.Printf("failed to read track data: %v\n", err)
-					return
-				}
-
-				fPath := path.Join("./Music/", album.Title, track.Item.Title+".flac")
-				if err := os.WriteFile(fPath, data, 0644); err != nil {
-					log.Printf("failed to save track file: %v\n", err)
-					return
-				}
-
-				artists := []string{}
-				for _, artist := range album.Artists {
-					artists = append(artists, artist.Name)
-				}
-
-				if err := taglib.WriteTags(fPath, map[string][]string{
-					taglib.Artist:      {album.Artist.Name},
-					taglib.Artists:     artists,
-					taglib.AlbumArtist: artists,
-					taglib.TrackNumber: {strconv.Itoa(track.Item.TrackNumber)},
-					taglib.Album:       {album.Title},
-					taglib.Title:       {track.Item.Title},
-					taglib.ReleaseDate: {album.ReleaseDate},
-				}, 0); err != nil {
-					log.Printf("failed to add metadata tags to track file: %v\n", err)
-				}
-
-				if err := taglib.WriteImage(fPath, albumCoverImg); err != nil {
-					log.Printf("failed to add album cover to track metadata: %v\n", err)
-				}
-
-				response.Lock()
-				response.count++
-				response.Unlock()
-			})
-		}
-
-		wg.Wait()
-
 		sendJSON(w, struct {
-			DownloadedFilesCount int `json:"downloadedFilesCount"`
-			TotalFilesCount      int `json:"totalFilesCount"`
-		}{
-			DownloadedFilesCount: response.count,
-			TotalFilesCount:      len(album.Items),
-		}, 200)
+			Ok bool `json:"ok"`
+		}{true}, 200)
 	})
 
+	go func() {
+		for {
+			time.Sleep(1 * time.Second)
+			if len(downloads) == 0 {
+				continue
+			}
+
+			for _, download := range downloads {
+				go func() {
+					download.Status = DownloadStatusInProgress
+
+					albumCoverImg, err := mClient.AlbumCoverImage(download.Album.CoverID)
+					if err != nil {
+						log.Printf("failed to download album cover: %v\n", err)
+					}
+
+					if err := os.Mkdir("./Music/"+download.Album.Title, 0777); err != nil {
+						return
+					}
+
+					var wg sync.WaitGroup
+					for _, track := range download.Album.Items {
+						wg.Go(func() {
+							info, err := mClient.TrackInfo(track.Item.ID, track.Item.AudioQuality)
+							if err != nil {
+								log.Printf("failed to get track info: %v\n", err)
+								return
+							}
+
+							manifest, err := mClient.DecodeManifest(info.Manifest)
+							if err != nil {
+								log.Printf("failed to decode track manifest: %v\n", err)
+								return
+							}
+
+							if manifest.EncryptionType != monochrome.TrackManifestEncryptionNone {
+								log.Println("file is encrypted; can't download")
+								return
+							}
+
+							if len(manifest.URLs) == 0 {
+								log.Println("track manifest doesn't have urls array")
+								return
+							}
+
+							resp, err := http.Get(manifest.URLs[0])
+							if err != nil {
+								log.Printf("failed to download track data: %v\n", err)
+								return
+							}
+							defer resp.Body.Close()
+
+							data, err := io.ReadAll(resp.Body)
+							if err != nil {
+								log.Printf("failed to read track data: %v\n", err)
+								return
+							}
+
+							fPath := path.Join("./Music/", download.Album.Title, track.Item.Title+".flac")
+							if err := os.WriteFile(fPath, data, 0644); err != nil {
+								log.Printf("failed to save track file: %v\n", err)
+								return
+							}
+
+							artists := []string{}
+							for _, artist := range download.Album.Artists {
+								artists = append(artists, artist.Name)
+							}
+
+							if err := taglib.WriteTags(fPath, map[string][]string{
+								taglib.Artist:      {download.Album.Artist.Name},
+								taglib.Artists:     artists,
+								taglib.AlbumArtist: artists,
+								taglib.TrackNumber: {strconv.Itoa(track.Item.TrackNumber)},
+								taglib.Album:       {download.Album.Title},
+								taglib.Title:       {track.Item.Title},
+								taglib.ReleaseDate: {download.Album.ReleaseDate},
+							}, 0); err != nil {
+								log.Printf("failed to add metadata tags to track file: %v\n", err)
+							}
+
+							if err := taglib.WriteImage(fPath, albumCoverImg); err != nil {
+								log.Printf("failed to add album cover to track metadata: %v\n", err)
+							}
+
+							download.Lock()
+							download.InstalledFiles++
+							download.Unlock()
+						})
+					}
+
+					download.Status = DownloadStatusCompleted
+					wg.Wait()
+				}()
+			}
+		}
+	}()
+
 	log.Println("starting http server")
 	if err := http.ListenAndServe(":5000", mux); err != nil {
 		log.Fatalf("failed to start http server: %v\n", err)

web/.gitignore

@@ -0,0 +1,24 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?

web/eslint.config.js

@@ -0,0 +1,23 @@
+import js from "@eslint/js";
+import globals from "globals";
+import reactHooks from "eslint-plugin-react-hooks";
+import reactRefresh from "eslint-plugin-react-refresh";
+import tseslint from "typescript-eslint";
+import { defineConfig, globalIgnores } from "eslint/config";
+
+export default defineConfig([
+  globalIgnores(["dist"]),
+  {
+    files: ["**/*.{ts,tsx}"],
+    extends: [
+      js.configs.recommended,
+      tseslint.configs.recommended,
+      reactHooks.configs.flat.recommended,
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+    },
+  },
+]);

web/index.html

@@ -0,0 +1,13 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <link rel="icon" type="image/svg+xml" href="/vite.svg" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>web</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>

web/package.json

@@ -0,0 +1,39 @@
+{
+  "name": "web",
+  "private": true,
+  "version": "0.0.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "tsc -b && vite build",
+    "lint": "eslint .",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "@tanstack/react-query": "^5.90.21",
+    "react": "^19.2.0",
+    "react-dom": "^19.2.0"
+  },
+  "devDependencies": {
+    "@eslint/js": "^9.39.1",
+    "@tailwindcss/vite": "^4.2.0",
+    "@types/node": "^24.10.1",
+    "@types/react": "^19.2.7",
+    "@types/react-dom": "^19.2.3",
+    "@vitejs/plugin-react": "^5.1.1",
+    "babel-plugin-react-compiler": "^1.0.0",
+    "eslint": "^9.39.1",
+    "eslint-plugin-react-hooks": "^7.0.1",
+    "eslint-plugin-react-refresh": "^0.4.24",
+    "globals": "^16.5.0",
+    "tailwindcss": "^4.2.0",
+    "typescript": "~5.9.3",
+    "typescript-eslint": "^8.48.0",
+    "vite": "^8.0.0-beta.13"
+  },
+  "pnpm": {
+    "overrides": {
+      "vite": "^8.0.0-beta.13"
+    }
+  }
+}

web/src/App.tsx

@@ -0,0 +1,104 @@
+import { useState } from "react";
+import { useSearchQuery, type Album } from "./api/useSearchQuery";
+import { useDebouncedValue } from "./hooks/useDebouncedValue";
+import { getContrastYIQ } from "./getContrastYIQ";
+import { useDownloadAlbumMutation } from "./api/useDownloadAlbumMutation";
+import { useDownloadsQuery } from "./api/useDownloadsQuery";
+
+export default function App() {
+  const [search, setSearch] = useState("");
+  const debouncedSearch = useDebouncedValue(search);
+
+  const { data } = useSearchQuery({
+    query: debouncedSearch,
+  });
+  const { data: downloads } = useDownloadsQuery();
+
+  const downloadAlbumMutation = useDownloadAlbumMutation();
+
+  const handleDownloadAlbum = (album: Album) => {
+    downloadAlbumMutation.mutate(
+      { albumId: album.id },
+      {
+        onError(error) {
+          console.log({ error });
+        },
+      },
+    );
+  };
+
+  return (
+    <div className="max-w-300 w-full mx-auto p-2">
+      <h1 className="text-3xl font-semibold">music-downloader</h1>
+
+      <div className="mt-4 flex flex-col gap-2">
+        {downloads?.map((item) => (
+          <div key={item.id} className="flex gap-2 p-2">
+            <img
+              src={`/cover/${item.album.cover}`}
+              alt=""
+              width={64}
+              height={64}
+            />
+            <div>
+              <p>{item.album.title}</p>
+              <p>
+                Downloaded {item.installedFiles}/{item.totalFiles}
+              </p>
+            </div>
+          </div>
+        ))}
+      </div>
+
+      <div className="mt-4">
+        <input
+          type="text"
+          placeholder="Search album..."
+          className="w-full p-1 border border-neutral-900"
+          value={search}
+          onChange={(e) => setSearch(e.target.value)}
+        />
+      </div>
+
+      <div className="mt-2 flex flex-col gap-2">
+        {data?.map((album) => {
+          const contrastColor = getContrastYIQ(album.vibrantColor);
+          const oppositeColor = contrastColor === "black" ? "white" : "black";
+
+          return (
+            <div
+              key={album.id}
+              className="flex gap-2 p-2"
+              style={{
+                backgroundColor: album.vibrantColor,
+                color: contrastColor,
+              }}
+            >
+              <img
+                src={`/cover/${album.cover}`}
+                alt=""
+                width={128}
+                height={128}
+              />
+              <div className="flex flex-col">
+                <p>{album.title}</p>
+                <p>{album.releaseDate}</p>
+                <p>{album.numberOfTracks} tracks</p>
+                <p>{album.audioQuality} quality</p>
+                {album.explicit && <p>Explicit</p>}
+              </div>
+              <button
+                type="button"
+                className="cursor-pointer ml-auto mt-auto py-1 px-2"
+                style={{ backgroundColor: oppositeColor, color: contrastColor }}
+                onClick={() => handleDownloadAlbum(album)}
+              >
+                Download
+              </button>
+            </div>
+          );
+        })}
+      </div>
+    </div>
+  );
+}

web/src/api/useDownloadAlbumMutation.ts

@@ -0,0 +1,14 @@
+import { useMutation } from "@tanstack/react-query";
+
+export const useDownloadAlbumMutation = () => {
+  return useMutation({
+    mutationFn: async ({ albumId }: { albumId: number }) => {
+      const resp = await fetch(`/download-album/${albumId}`);
+      if (!resp.ok) {
+        const data = (await resp.json()) as { error: string };
+        throw new Error(data.error);
+      }
+      return await resp.json();
+    },
+  });
+};

web/src/api/useDownloadsQuery.ts

@@ -0,0 +1,19 @@
+import { useQuery } from "@tanstack/react-query";
+import type { Album } from "./useSearchQuery";
+
+export type DownloadItem = {
+  id: number;
+  album: Album;
+  installedFiles: number;
+  totalFiles: number;
+};
+
+export const useDownloadsQuery = () => {
+  return useQuery({
+    queryKey: ["downloads"],
+    queryFn: async () => {
+      const resp = await fetch("/downloads");
+      return (await resp.json()) as DownloadItem[];
+    },
+  });
+};

web/src/api/useSearchQuery.ts

@@ -0,0 +1,33 @@
+import { useQuery } from "@tanstack/react-query";
+
+export type Album = {
+  id: number;
+  title: string;
+  duration: number;
+  numberOfTracks: number;
+  releaseDate: string;
+  type: "ALBUM";
+  url: string;
+  cover: string;
+  vibrantColor: string;
+  explicit: boolean;
+  audioQuality: "LOSSLESS" | "LOW";
+};
+
+export type SearchQueryParams = {
+  query: string;
+};
+
+export const useSearchQuery = (params: SearchQueryParams) => {
+  return useQuery({
+    queryKey: ["search", params],
+    enabled: !!params.query,
+    queryFn: async () => {
+      const q = new URLSearchParams();
+      q.set("q", params.query);
+
+      const resp = await fetch(`/search?${q.toString()}`);
+      return (await resp.json()) as Album[];
+    },
+  });
+};

web/src/getContrastYIQ.ts

@@ -0,0 +1,25 @@
+export function getContrastYIQ(hexcolor: string) {
+  // Remove leading # if present
+  if (hexcolor.startsWith("#")) {
+    hexcolor = hexcolor.slice(1);
+  }
+
+  // Handle 3-digit hex codes (e.g., #abc → #aabbcc)
+  if (hexcolor.length === 3) {
+    hexcolor = hexcolor
+      .split("")
+      .map((c) => c + c)
+      .join("");
+  }
+
+  // Parse RGB values
+  const r = parseInt(hexcolor.substr(0, 2), 16);
+  const g = parseInt(hexcolor.substr(2, 2), 16);
+  const b = parseInt(hexcolor.substr(4, 2), 16);
+
+  // Calculate YIQ brightness
+  const yiq = (r * 299 + g * 587 + b * 114) / 1000;
+
+  // Return black or white based on contrast
+  return yiq >= 128 ? "black" : "white";
+}

web/src/hooks/useDebouncedValue.ts

@@ -0,0 +1,14 @@
+import { useState, useEffect } from "react";
+
+export function useDebouncedValue<T>(value: T, wait: number = 300): T {
+  const [debouncedValue, setDebouncedValue] = useState(value);
+  useEffect(() => {
+    const timer = setTimeout(() => {
+      setDebouncedValue(value);
+    }, wait);
+    return () => {
+      clearTimeout(timer);
+    };
+  }, [value, wait]);
+  return debouncedValue;
+}

web/src/index.css

@@ -0,0 +1 @@
+@import "tailwindcss";

web/src/main.tsx

@@ -0,0 +1,21 @@
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+import "./index.css";
+import App from "./App.tsx";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+
+const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: {
+      retry: false,
+    },
+  },
+});
+
+createRoot(document.getElementById("root")!).render(
+  <StrictMode>
+    <QueryClientProvider client={queryClient}>
+      <App />
+    </QueryClientProvider>
+  </StrictMode>,
+);

web/tsconfig.app.json

@@ -0,0 +1,28 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
+    "target": "ES2022",
+    "useDefineForClassFields": true,
+    "lib": ["ES2022", "DOM", "DOM.Iterable"],
+    "module": "ESNext",
+    "types": ["vite/client"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+    "jsx": "react-jsx",
+
+    /* Linting */
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true
+  },
+  "include": ["src"]
+}

web/tsconfig.json

@@ -0,0 +1,7 @@
+{
+  "files": [],
+  "references": [
+    { "path": "./tsconfig.app.json" },
+    { "path": "./tsconfig.node.json" }
+  ]
+}

web/tsconfig.node.json

@@ -0,0 +1,26 @@
+{
+  "compilerOptions": {
+    "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.node.tsbuildinfo",
+    "target": "ES2023",
+    "lib": ["ES2023"],
+    "module": "ESNext",
+    "types": ["node"],
+    "skipLibCheck": true,
+
+    /* Bundler mode */
+    "moduleResolution": "bundler",
+    "allowImportingTsExtensions": true,
+    "verbatimModuleSyntax": true,
+    "moduleDetection": "force",
+    "noEmit": true,
+
+    /* Linting */
+    "strict": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "erasableSyntaxOnly": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUncheckedSideEffectImports": true
+  },
+  "include": ["vite.config.ts"]
+}

web/vite.config.ts

@@ -0,0 +1,15 @@
+import { defineConfig } from "vite";
+import react from "@vitejs/plugin-react";
+import tailwindcss from "@tailwindcss/vite";
+
+// https://vite.dev/config/
+export default defineConfig({
+  plugins: [
+    tailwindcss(),
+    react({
+      babel: {
+        plugins: [["babel-plugin-react-compiler"]],
+      },
+    }),
+  ],
+});