Improve gitignore

.dockerignore

@@ -0,0 +1,2 @@
+sheetless.db
+sheetless-server

.gitignore

@@ -1 +1,3 @@
 /.direnv/
+sheetless-server
+sheetless.db

Dockerfile

@@ -0,0 +1,32 @@
+# Build stage
+FROM golang:1.21-alpine AS builder
+
+WORKDIR /app
+
+# Copy go mod and sum files
+COPY src/go.mod src/go.sum .
+
+# Download dependencies
+RUN go mod download
+
+# Copy source code
+COPY ./src/ .
+
+# Build the application
+RUN go build -o sheetless-server 
+
+# Runtime stage
+FROM alpine:latest
+
+RUN apk --no-cache add ca-certificates
+
+WORKDIR /app/
+
+# Copy the binary from builder
+COPY --from=builder /app .
+
+# Expose port
+EXPOSE 8080
+
+# Run the application
+CMD ["./sheetless-server"]

src/database/connection.go

@@ -0,0 +1,27 @@
+package database
+
+import (
+	"log"
+	"sheetless-server/models"
+
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+var DB *gorm.DB
+
+func InitDatabase() {
+	var err error
+	DB, err = gorm.Open(sqlite.Open("sheetless.db"), &gorm.Config{})
+	if err != nil {
+		log.Fatal("Failed to connect to database:", err)
+	}
+
+	// Auto migrate the schema
+	err = DB.AutoMigrate(&models.User{}, &models.Sheet{}, &models.Composer{})
+	if err != nil {
+		log.Fatal("Failed to migrate database:", err)
+	}
+
+	log.Println("Database connected and migrated successfully")
+}

src/go.mod

@@ -5,6 +5,7 @@ go 1.21
 require (
 	github.com/gin-gonic/gin v1.9.1
 	github.com/golang-jwt/jwt/v5 v5.0.0
+	github.com/google/uuid v1.6.0
 	golang.org/x/crypto v0.9.0
 	gorm.io/driver/sqlite v1.5.4
 	gorm.io/gorm v1.25.5

src/go.sum

@@ -5,6 +5,7 @@ github.com/chenzhuoyu/base64x v0.0.0-20211019084208-fb5309c8db06/go.mod h1:DH46F
 github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311 h1:qSGYFH7+jGhDF8vLC+iwCD4WpbV1EBDSzWkJODFLams=
 github.com/chenzhuoyu/base64x v0.0.0-20221115062448-fe3a3abad311/go.mod h1:b583jCggY9gE99b6G5LEC39OIiVsWj+R97kbl5odCEk=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/gabriel-vasile/mimetype v1.4.2 h1:w5qFW6JKBz9Y393Y4q372O9A7cUSequkh1Q7OhCmWKU=
 github.com/gabriel-vasile/mimetype v1.4.2/go.mod h1:zApsH/mKG4w07erKIaJPFiX0Tsq9BFQgN3qGY5GnNgA=
@@ -12,6 +13,8 @@ github.com/gin-contrib/sse v0.1.0 h1:Y/yl/+YNO8GZSjAhjMsSuLt29uWRFHdHYUb5lYOV9qE
 github.com/gin-contrib/sse v0.1.0/go.mod h1:RHrZQHXnP2xjPF+u1gW/2HnVO7nvIa9PG3Gm+fLHvGI=
 github.com/gin-gonic/gin v1.9.1 h1:4idEAncQnU5cB7BeOkPtxjfCSye0AAm1R0RVIqJ+Jmg=
 github.com/gin-gonic/gin v1.9.1/go.mod h1:hPrL7YrpYKXt5YId3A/Tnip5kqbEAP+KLuI3SUcPTeU=
+github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
+github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
 github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
 github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
 github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
@@ -23,8 +26,11 @@ github.com/goccy/go-json v0.10.2/go.mod h1:6MelG93GURQebXPDq3khkgXZkazVtN9CRI+MG
 github.com/golang-jwt/jwt/v5 v5.0.0 h1:1n1XNM9hk7O9mnQoNBGolZvzebBQ7p93ULHRc28XJUE=
 github.com/golang-jwt/jwt/v5 v5.0.0/go.mod h1:pqrtFR0X4osieyHYxtmOUWsAWrfe1Q5UVIyoH402zdk=
 github.com/golang/protobuf v1.5.0/go.mod h1:FsONVRAS9T7sI+LIUmWTfcYkHO4aIWwzhcaSAoJOfIk=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
 github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
 github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
+github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
+github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD/E=
 github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
 github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
@@ -47,6 +53,7 @@ github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9G
 github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
 github.com/pelletier/go-toml/v2 v2.0.8 h1:0ctb6s9mE31h0/lhu+J6OPmVeDxJn+kYnJc2jZR9tGQ=
 github.com/pelletier/go-toml/v2 v2.0.8/go.mod h1:vuYfssBdrU2XDZ9bYydBu6t+6a6PYNcZljzZR9VXg+4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
@@ -57,6 +64,7 @@ github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
 github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.3 h1:RP3t2pwF7cMEbC1dqtB6poj3niw/9gnV4Cjg5oW5gtY=
 github.com/stretchr/testify v1.8.3/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/twitchyliquid64/golang-asm v0.15.1 h1:SU5vSMR7hnwNxj24w34ZyCi/FmDZTkS4MhqMhdFk5YI=
 github.com/twitchyliquid64/golang-asm v0.15.1/go.mod h1:a1lVb/DtPvCB8fslRZhAngC2+aY1QWCk3Cedj/Gdt08=
@@ -75,10 +83,12 @@ golang.org/x/sys v0.8.0 h1:EBmGv8NaZBZTWvrbjNoL6HVt+IVy3QDQpJs7VRIw3tU=
 golang.org/x/sys v0.8.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/text v0.9.0 h1:2sjJmO8cDvYveuX97RDLsxlyUxLl+GHoLxBiRdHllBE=
 golang.org/x/text v0.9.0/go.mod h1:e1OnstbJyHTd6l/uOt8jFFHp6TRDWZR/bV3emEE/zU8=
+golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543 h1:E7g+9GITq07hpfrRu66IVDexMakfv52eLZ2CXBWiKr4=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 google.golang.org/protobuf v1.26.0-rc.1/go.mod h1:jlhhOSvTdKEhbULTjvd4ARK9grFBp09yW+WbY/TyQbw=
 google.golang.org/protobuf v1.30.0 h1:kPPoIgf3TsEvrm0PFe15JQ+570QVxYzEvvHqChK+cng=
 google.golang.org/protobuf v1.30.0/go.mod h1:HV8QOd/L58Z+nl8r43ehVNZIU/HEI6OcFqwMG9pJV4I=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

src/handlers/auth.go

@@ -0,0 +1,96 @@
+package handlers
+
+import (
+	"net/http"
+	"sheetless-server/database"
+	"sheetless-server/models"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/golang-jwt/jwt/v5"
+	"golang.org/x/crypto/bcrypt"
+)
+
+var jwtSecret = []byte("your-secret-key") // TODO: In production, use environment variable
+
+type RegisterRequest struct {
+	Username string `json:"username" binding:"required"`
+	Email    string `json:"email" binding:"required,email"`
+	Password string `json:"password" binding:"required,min=6"`
+}
+
+type LoginRequest struct {
+	Username string `json:"username" binding:"required"`
+	Password string `json:"password" binding:"required"`
+}
+
+func Register(c *gin.Context) {
+	var req RegisterRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Check if user already exists
+	var existingUser models.User
+	if err := database.DB.Where("username = ? OR email = ?", req.Username, req.Email).First(&existingUser).Error; err == nil {
+		c.JSON(http.StatusConflict, gin.H{"error": "User already exists"})
+		return
+	}
+
+	// Hash password
+	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(req.Password), bcrypt.DefaultCost)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to hash password"})
+		return
+	}
+
+	// Create user
+	user := models.User{
+		Username: req.Username,
+		Email:    req.Email,
+		Password: string(hashedPassword),
+	}
+
+	if err := database.DB.Create(&user).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create user"})
+		return
+	}
+
+	c.JSON(http.StatusCreated, gin.H{"message": "User created successfully"})
+}
+
+func Login(c *gin.Context) {
+	var req LoginRequest
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Find user
+	var user models.User
+	if err := database.DB.Where("username = ?", req.Username).First(&user).Error; err != nil {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
+		return
+	}
+
+	// Check password
+	if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(req.Password)); err != nil {
+		c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid credentials"})
+		return
+	}
+
+	// Generate JWT token
+	token := jwt.NewWithClaims(jwt.SigningMethodHS256, jwt.MapClaims{
+		"user_id": user.ID,
+		"exp":     time.Now().Add(time.Hour * 24).Unix(),
+	})
+
+	tokenString, err := token.SignedString(jwtSecret)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to generate token"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"token": tokenString})
+}

src/handlers/composers.go

@@ -0,0 +1,96 @@
+package handlers
+
+import (
+	"errors"
+	"net/http"
+	"sheetless-server/database"
+	"sheetless-server/models"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+func AddComposer(c *gin.Context) {
+	var req struct {
+		Name string `json:"name" binding:"required"`
+		Bio  string `json:"bio"`
+	}
+
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	uuid, err := GenerateNonexistentComposerUuid()
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Could not generate composer uuid"})
+		return
+	}
+
+	composer := models.Composer{
+		Uuid:      *uuid,
+		Name:      req.Name,
+		Bio:       req.Bio,
+		CreatedAt: time.Now(),
+		UpdatedAt: time.Now(),
+	}
+
+	if err := database.DB.Create(&composer).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create composer"})
+		return
+	}
+
+	c.JSON(http.StatusCreated, gin.H{
+		"message":  "Composer created successfully",
+		"composer": composer,
+	})
+}
+
+func ListComposers(c *gin.Context) {
+	var composers []models.Composer
+
+	if err := database.DB.Find(&composers).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch composers"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"composers": composers})
+}
+
+func GetComposer(c *gin.Context) {
+	uuid, err := uuid.Parse(c.Param("uuid"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid composer ID"})
+		return
+	}
+
+	var composer models.Composer
+	if err := database.DB.First(&composer, uuid).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Composer not found"})
+		return
+	}
+	c.JSON(http.StatusOK, composer)
+}
+
+func GenerateNonexistentComposerUuid() (*uuid.UUID, error) {
+	for i := 0; i < 10; i++ {
+		uuid := uuid.New()
+
+		var exists bool
+		err := database.DB.Model(&models.Composer{}).
+			Select("count(*) > 0").
+			Where("uuid = ?", uuid).
+			Find(&exists).
+			Error
+
+		if err != nil {
+			return nil, err
+		}
+
+		if !exists {
+			return &uuid, nil
+		}
+	}
+	return nil, errors.New("Somehow unable to generate new uuid for sheet.")
+}

src/handlers/sheets.go

@@ -0,0 +1,187 @@
+package handlers
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"sheetless-server/database"
+	"sheetless-server/models"
+	"sheetless-server/utils"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+)
+
+const uploadDir = "./uploads"
+
+func init() {
+	// Create uploads directory if it doesn't exist
+	if err := os.MkdirAll(uploadDir, 0755); err != nil {
+		panic("Failed to create uploads directory: " + err.Error())
+	}
+}
+
+func UploadSheet(c *gin.Context) {
+	// Get form data
+	title := c.PostForm("title")
+	if title == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Title is required"})
+		return
+	}
+
+	composerUUIDStr := c.PostForm("composer_uuid")
+	if composerUUIDStr == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Composer UUID is required"})
+		return
+	}
+
+	composerUUID, err := uuid.Parse(composerUUIDStr)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid composer UUID"})
+		return
+	}
+
+	var composer models.Composer
+	if err := database.DB.First(&composer, composerUUID).Error; err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Composer not found"})
+		return
+	}
+
+	description := c.PostForm("description")
+
+	// Get uploaded file
+	file, header, err := c.Request.FormFile("file")
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "File upload failed"})
+		return
+	}
+	defer file.Close()
+
+	// Validate file type (should be PDF)
+	if filepath.Ext(header.Filename) != ".pdf" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Only PDF files are allowed"})
+		return
+	}
+
+	// Generate unique filename
+	filename := fmt.Sprintf("%d%s", time.Now().Unix(), filepath.Ext(header.Filename))
+	filePath := filepath.Join(uploadDir, filename)
+
+	// Save file
+	out, err := os.Create(filePath)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to save file"})
+		return
+	}
+	defer out.Close()
+
+	_, err = io.Copy(out, file)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to save file"})
+		return
+	}
+
+	// Get file size
+	fileInfo, err := out.Stat()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to get file info"})
+		return
+	}
+
+	fileHash, err := utils.FileHashFromUpload(out)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed calculating hash"})
+		return
+	}
+
+	uuid, err := GenerateNonexistentSheetUuid()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed generating sheet uuid"})
+		return
+	}
+
+	// Create database record
+	sheet := models.Sheet{
+		Uuid:        *uuid,
+		Title:       title,
+		Description: description,
+		FilePath:    filePath,
+		FileSize:    fileInfo.Size(),
+		FileHash:    fileHash,
+		ComposerID:  composer.Uuid,
+		CreatedAt:   time.Now(),
+		UpdatedAt:   time.Now(),
+	}
+
+	if err := database.DB.Create(&sheet).Error; err != nil {
+		// Clean up file if database insert fails
+		os.Remove(filePath)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to save sheet metadata"})
+		return
+	}
+
+	c.JSON(http.StatusCreated, gin.H{
+		"message": "Sheet uploaded successfully",
+		"sheet":   sheet,
+	})
+}
+
+func ListSheets(c *gin.Context) {
+	var sheets []models.Sheet
+
+	if err := database.DB.Preload("Composer").Find(&sheets).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to fetch sheets"})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{"sheets": sheets})
+}
+
+func DownloadSheet(c *gin.Context) {
+	uuid, err := uuid.Parse(c.Param("uuid"))
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid sheet uuid"})
+		return
+	}
+
+	var sheet models.Sheet
+	if err := database.DB.First(&sheet, uuid).Error; err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": "Sheet not found"})
+		return
+	}
+
+	if _, err := os.Stat(sheet.FilePath); os.IsNotExist(err) {
+		c.JSON(http.StatusNotFound, gin.H{"error": "File not found"})
+		return
+	}
+
+	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", filepath.Base(sheet.FilePath)))
+	c.Header("Content-Type", "application/pdf")
+	c.File(sheet.FilePath)
+}
+
+func GenerateNonexistentSheetUuid() (*uuid.UUID, error) {
+	for i := 0; i < 10; i++ {
+		uuid := uuid.New()
+
+		var exists bool
+		err := database.DB.Model(&models.Sheet{}).
+			Select("count(*) > 0").
+			Where("uuid = ?", uuid).
+			Find(&exists).
+			Error
+
+		if err != nil {
+			return nil, err
+		}
+
+		if !exists {
+			return &uuid, nil
+		}
+	}
+	return nil, errors.New("Somehow unable to generate new uuid for sheet.")
+}

src/main.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"log"
+	"sheetless-server/database"
+	"sheetless-server/routes"
+	"sheetless-server/sync"
+	"time"
+
+	"github.com/gin-gonic/gin"
+)
+
+func main() {
+	database.InitDatabase()
+
+	// Start sync runner
+	go func() {
+		ticker := time.NewTicker(1 * time.Minute)
+		defer ticker.Stop()
+		for {
+			select {
+			case <-ticker.C:
+				if err := sync.SyncSheets(); err != nil {
+					log.Printf("Sync error: %v", err)
+				}
+			}
+		}
+	}()
+
+	r := gin.Default()
+
+	routes.SetupRoutes(r)
+
+	log.Println("Server starting on port 8080...")
+	if err := r.Run(":8080"); err != nil {
+		log.Fatal("Failed to start server:", err)
+	}
+}

src/middleware/auth.go

@@ -0,0 +1,50 @@
+package middleware
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+var jwtSecret = []byte("your-secret-key") // Should match the one in handlers/auth.go
+
+func AuthMiddleware() gin.HandlerFunc {
+	return func(c *gin.Context) {
+		authHeader := c.GetHeader("Authorization")
+		if authHeader == "" {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Authorization header required"})
+			c.Abort()
+			return
+		}
+
+		// Extract token from "Bearer <token>" format
+		tokenString := strings.TrimPrefix(authHeader, "Bearer ")
+		if tokenString == authHeader {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token format"})
+			c.Abort()
+			return
+		}
+
+		// Parse and validate token
+		token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+			return jwtSecret, nil
+		})
+
+		if err != nil || !token.Valid {
+			c.JSON(http.StatusUnauthorized, gin.H{"error": "Invalid token"})
+			c.Abort()
+			return
+		}
+
+		// Extract claims
+		if claims, ok := token.Claims.(jwt.MapClaims); ok {
+			if userID, ok := claims["user_id"].(float64); ok {
+				c.Set("user_id", uint(userID))
+			}
+		}
+
+		c.Next()
+	}
+}

src/models/composer.go

@@ -0,0 +1,17 @@
+package models
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+	"gorm.io/gorm"
+)
+
+type Composer struct {
+	Uuid      uuid.UUID      `json:"uuid" gorm:"type:uuid;primaryKey"`
+	Name      string         `json:"name" gorm:"not null"`
+	Bio       string         `json:"bio"`
+	CreatedAt time.Time      `json:"created_at"`
+	UpdatedAt time.Time      `json:"updated_at"`
+	DeletedAt gorm.DeletedAt `json:"-" gorm:"index"`
+}

src/models/sheet.go

@@ -0,0 +1,22 @@
+package models
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+	"gorm.io/gorm"
+)
+
+type Sheet struct {
+	Uuid        uuid.UUID      `json:"uuid" gorm:"type:uuid;primaryKey"`
+	Title       string         `json:"title" gorm:"not null"`
+	Description string         `json:"description"`
+	FilePath    string         `json:"file_path" gorm:"not null"`
+	FileSize    int64          `json:"file_size"`
+	FileHash    uint64         `json:"file_hash"`
+	ComposerId  uuid.UUID      `json:"composer_id"`
+	Composer    Composer       `json:"composer" gorm:"foreignKey:ComposerId"`
+	CreatedAt   time.Time      `json:"created_at"`
+	UpdatedAt   time.Time      `json:"updated_at"`
+	DeletedAt   gorm.DeletedAt `json:"-" gorm:"index"`
+}

src/models/user.go

@@ -0,0 +1,17 @@
+package models
+
+import (
+	"time"
+
+	"gorm.io/gorm"
+)
+
+type User struct {
+	ID        uint           `json:"id" gorm:"primaryKey"`
+	Username  string         `json:"username" gorm:"unique;not null"`
+	Email     string         `json:"email" gorm:"unique;not null"`
+	Password  string         `json:"-" gorm:"not null"` // Don't include in JSON responses
+	CreatedAt time.Time      `json:"created_at"`
+	UpdatedAt time.Time      `json:"updated_at"`
+	DeletedAt gorm.DeletedAt `json:"-" gorm:"index"`
+}

src/routes/routes.go

@@ -0,0 +1,36 @@
+package routes
+
+import (
+	"sheetless-server/handlers"
+	"sheetless-server/middleware"
+
+	"github.com/gin-gonic/gin"
+)
+
+func SetupRoutes(r *gin.Engine) {
+	// Public routes
+	auth := r.Group("/auth")
+	{
+		auth.POST("/register", handlers.Register)
+		auth.POST("/login", handlers.Login)
+	}
+
+	// Protected routes
+	api := r.Group("/api")
+	api.Use(middleware.AuthMiddleware())
+	{
+		sheets := api.Group("/sheets")
+		{
+			sheets.POST("/upload", handlers.UploadSheet)
+			sheets.GET("/list", handlers.ListSheets)
+			sheets.GET("/get/:uuid", handlers.DownloadSheet)
+		}
+
+		composers := api.Group("/composers")
+		{
+			composers.POST("/add", handlers.AddComposer)
+			composers.GET("/list", handlers.ListComposers)
+			composers.GET("/get/:uuid", handlers.GetComposer)
+		}
+	}
+}

src/sync/sync.go

@@ -0,0 +1,102 @@
+package sync
+
+import (
+	"log"
+	"os"
+	"path/filepath"
+	"sheetless-server/database"
+	"sheetless-server/handlers"
+	"sheetless-server/models"
+	"sheetless-server/utils"
+	"time"
+)
+
+const uploadDir = "./uploads"
+
+func SyncSheets() error {
+	// Get all sheets
+	var sheets []models.Sheet
+	if err := database.DB.Find(&sheets).Error; err != nil {
+		return err
+	}
+
+	// Maps
+	pathsInDb := make(map[string]*models.Sheet)
+	hashToSheets := make(map[uint64][]*models.Sheet)
+	for i := range sheets {
+		sheet := &sheets[i]
+		pathsInDb[sheet.FilePath] = sheet
+		hashToSheets[sheet.FileHash] = append(hashToSheets[sheet.FileHash], sheet)
+	}
+
+	// Walk uploads dir
+	files, err := os.ReadDir(uploadDir)
+	if err != nil {
+		return err
+	}
+
+	for _, file := range files {
+		if file.IsDir() {
+			continue
+		}
+		filePath := filepath.Join(uploadDir, file.Name())
+		hash, err := utils.FileHash(filePath)
+		if err != nil {
+			log.Printf("Error hashing file %s: %v", filePath, err)
+			continue
+		}
+		info, err := file.Info()
+		if err != nil {
+			log.Printf("Error getting file info %s: %v", filePath, err)
+			continue
+		}
+
+		existingSheet, exists := pathsInDb[filePath]
+		if exists {
+			if existingSheet.FileHash != hash {
+				// Case 1: File has been altered -> update hash
+				existingSheet.FileHash = hash
+				existingSheet.UpdatedAt = time.Now()
+				if err := database.DB.Save(existingSheet).Error; err != nil {
+					log.Printf("Error updating sheet hash for %s: %v", filePath, err)
+				}
+			}
+		} else {
+			sheetsWithHash, hasHash := hashToSheets[hash]
+			if hasHash {
+				for _, s := range sheetsWithHash {
+					if _, err := os.Stat(s.FilePath); os.IsNotExist(err) {
+						// Case 2: File has been renamed or moved -> update path
+						s.FilePath = filePath
+						s.UpdatedAt = time.Now()
+						if err := database.DB.Save(s).Error; err != nil {
+							log.Printf("Error updating sheet path for %s: %v", filePath, err)
+						}
+						break
+					}
+				}
+			} else {
+				// Case 3: New sheets file -> Add to database
+				uuid, err := handlers.GenerateNonexistentSheetUuid()
+				if err != nil {
+					log.Printf("Error generating uuid: %v", err)
+					continue
+				}
+				newSheet := models.Sheet{
+					Uuid:      *uuid,
+					Title:     file.Name(), // use filename as title
+					FilePath:  filePath,
+					FileSize:  info.Size(),
+					FileHash:  hash,
+					CreatedAt: time.Now(),
+					UpdatedAt: time.Now(),
+				}
+				if err := database.DB.Create(&newSheet).Error; err != nil {
+					log.Printf("Error creating new sheet for %s: %v", filePath, err)
+				}
+			}
+		}
+	}
+
+	return nil
+}

src/utils/filehash.go

@@ -0,0 +1,32 @@
+package utils
+
+import (
+	"hash/fnv"
+	"io"
+	"mime/multipart"
+	"os"
+)
+
+func FileHashFromUpload(file multipart.File) (uint64, error) {
+	h := fnv.New64a()
+	if _, err := io.Copy(h, file); err != nil {
+		return 0, err
+	}
+
+	return h.Sum64(), nil
+}
+
+func FileHash(path string) (uint64, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return 0, err
+	}
+	defer f.Close()
+
+	h := fnv.New64a()
+	if _, err := io.Copy(h, f); err != nil {
+		return 0, err
+	}
+
+	return h.Sum64(), nil
+}