feat: complete business improvement plan implementation

backend/.env.example

@@ -7,3 +7,15 @@ DATABASE_URL="mysql://ulticode:ulticode@localhost:23306/ulticode"
 # Must be at least 32 characters long for cryptographic security
 # Generate a secure random string for production
 JWT_SECRET="ulticode-super-secret-jwt-key-min-32-chars"
+
+# Stripe API keys for payment processing
+# Get these from https://dashboard.stripe.com/apikeys
+STRIPE_SECRET_KEY="sk_test_xxx"
+STRIPE_WEBHOOK_SECRET="whsec_xxx"
+STRIPE_PRICE_PREMIUM_MONTHLY="price_xxx"
+STRIPE_PRICE_PREMIUM_YEARLY="price_xxx"
+
+# Docker sandbox configuration
+DOCKER_SOCKET="/var/run/docker.sock"
+JUDGE_IMAGE="ulti-judge:latest"
+SANDBOX_TYPE="docker"

backend/judge/runners/run-rust.sh

@@ -0,0 +1,76 @@
+#!/bin/bash
+# Rust code runner for the sandbox
+# Compiles and executes Rust code with provided inputs
+
+set -e
+
+TIME_LIMIT_MS="${TIME_LIMIT_MS:-15000}"
+INPUT_FILE="${INPUT_FILE:-/sandbox/input/args.json}"
+CODE_FILE="${CODE_FILE:-/sandbox/code/solution.rs}"
+WORK_DIR="/sandbox/code"
+OUTPUT_BIN="${WORK_DIR}/solution"
+
+# Function to output JSON error
+output_error() {
+    local status="$1"
+    local error="$2"
+    local time="${3:-0}"
+    local memory="${4:-0}"
+    echo "{\"status\": \"${status}\", \"error\": \"${error}\", \"time\": ${time}, \"memory\": ${memory}}"
+    exit 1
+}
+
+cd "$WORK_DIR"
+
+# Compile Rust code with optimizations
+COMPILE_START=$(date +%s%3N)
+if ! rustc -O -o "$OUTPUT_BIN" "$CODE_FILE" 2>compile_error.txt; then
+    COMPILE_ERROR=$(cat compile_error.txt | head -20)
+    output_error "Compile Error" "$COMPILE_ERROR"
+fi
+COMPILE_TIME=$(($(date +%s%3N) - COMPILE_START))
+
+# Prepare input
+if [ -f "$INPUT_FILE" ]; then
+    STDIN_INPUT=$(cat "$INPUT_FILE" | python3 -c "
+import json, sys
+data = json.load(sys.stdin)
+args = data.get('args', [])
+for arg in args:
+    if isinstance(arg, list):
+        print(' '.join(map(str, arg)))
+    else:
+        print(str(arg))
+" 2>/dev/null || echo "")
+else
+    STDIN_INPUT=""
+fi
+
+# Execute with timeout
+TIMEOUT_SEC=$((TIME_LIMIT_MS / 1000 + 2))
+EXEC_START=$(date +%s%3N)
+
+if [ -n "$STDIN_INPUT" ]; then
+    OUTPUT=$(echo "$STDIN_INPUT" | timeout ${TIMEOUT_SEC}s "$OUTPUT_BIN" 2>&1) || EXEC_STATUS=$?
+else
+    OUTPUT=$(timeout ${TIMEOUT_SEC}s "$OUTPUT_BIN" 2>&1) || EXEC_STATUS=$?
+fi
+
+EXEC_TIME=$(($(date +%s%3N) - EXEC_START))
+EXEC_STATUS=${EXEC_STATUS:-0}
+
+# Get memory usage
+MEMORY_MB=$(ps -o rss= -p $$ 2>/dev/null | awk '{printf "%.2f", $1/1024}' || echo "0")
+
+if [ $EXEC_STATUS -eq 124 ]; then
+    output_error "Time Limit Exceeded" "Execution timed out" "$TIME_LIMIT_MS" "$MEMORY_MB"
+elif [ $EXEC_STATUS -ne 0 ]; then
+    CLEANED_OUTPUT=$(echo "$OUTPUT" | grep -v "^$" | head -20)
+    output_error "Runtime Error" "$CLEANED_OUTPUT" "$EXEC_TIME" "$MEMORY_MB"
+else
+    CLEANED_OUTPUT=$(echo "$OUTPUT" | sed 's/"/\\"/g' | tr '\n' '\\n' | sed 's/\\n$//')
+    printf '{"status": "Success", "output": "%s", "time": %d, "memory": %.2f}\n' \
+        "$CLEANED_OUTPUT" \
+        "$EXEC_TIME" \
+        "$MEMORY_MB"
+fi

backend/package.json

@@ -38,6 +38,7 @@
     "@nestjs/platform-express": "^11.0.1",
     "@nestjs/platform-socket.io": "^11.0.1",
     "@nestjs/schedule": "^6.1.0",
+    "@nestjs/swagger": "^11.2.5",
     "@nestjs/throttler": "^6.5.0",
     "@nestjs/websockets": "^11.0.1",
     "@prisma/client": "^6.19.0",
@@ -62,6 +63,7 @@
     "reflect-metadata": "^0.2.2",
     "rxjs": "^7.8.1",
     "socket.io": "^4.8.1",
+    "stripe": "^20.4.0",
     "typescript": "^5.7.3",
     "uuid": "^11.1.0"
   },
@@ -79,6 +81,7 @@
     "@types/jest": "^30.0.0",
     "@types/node": "^22.10.7",
     "@types/nodemailer": "^7.0.11",
+    "@types/stripe": "^8.0.417",
     "@types/supertest": "^6.0.2",
     "@types/uuid": "^10.0.0",
     "eslint": "^9.18.0",

backend/prisma/schema.prisma

@@ -8,20 +8,27 @@ datasource db {
 }
 
 model Subscription {
-  id           String             @id @default(uuid()) @db.VarChar(40)
-  user_id      String             @db.VarChar(40)
-  plan         SubscriptionPlan   @default(FREE)
-  status       SubscriptionStatus @default(ACTIVE)
-  started_at   DateTime           @default(now())
-  expires_at   DateTime?
-  cancelled_at DateTime?
-  created_at   DateTime           @default(now())
-  updated_at   DateTime           @updatedAt
+  id                    String             @id @default(uuid()) @db.VarChar(40)
+  user_id               String             @db.VarChar(40)
+  plan                  SubscriptionPlan   @default(FREE)
+  status                SubscriptionStatus @default(ACTIVE)
+  started_at            DateTime           @default(now())
+  expires_at            DateTime?
+  cancelled_at          DateTime?
+  // Stripe payment integration fields
+  stripe_customer_id    String?            @db.VarChar(255)
+  stripe_subscription_id String?           @db.VarChar(255)
+  stripe_price_id       String?            @db.VarChar(255)
+  stripe_current_period_end DateTime?
+  created_at            DateTime           @default(now())
+  updated_at            DateTime           @updatedAt
 
   user User @relation(fields: [user_id], references: [id], onDelete: Cascade)
 
   @@index([user_id])
   @@index([status])
+  @@index([stripe_customer_id])
+  @@index([stripe_subscription_id])
   @@map("subscriptions")
 }
 
@@ -104,6 +111,9 @@ model Problem {
   flag_reviewed_by     String?                      @db.VarChar(40)
   flag_reviewed_at     DateTime?
   flag_notes           String?                      @db.Text
+  created_at           DateTime                     @default(now())
+  updated_at           DateTime                     @default(now()) @updatedAt
+  version              Int                          @default(1)
   contestProblems      ContestProblem[]
   detail               ProblemDetail?
   examples             ProblemExample[]
@@ -114,6 +124,7 @@ model Problem {
   solutions            Solution[]
   submissions          Submission[]
   testCases            TestCase[]
+  versions             ProblemVersion[]
 
   @@index([difficulty])
   @@index([slug])
@@ -122,9 +133,39 @@ model Problem {
   @@index([is_flagged, is_deleted])
   @@index([difficulty, is_published, is_deleted])
   @@index([created_at])
+  @@index([version])
   @@map("problems")
 }
 
+model ProblemVersion {
+  id              String   @id @default(cuid())
+  problem_id      BigInt
+  version_number  Int
+  title           String   @db.VarChar(255)
+  slug            String   @db.VarChar(120)
+  difficulty      Difficulty
+  is_premium      Boolean  @default(false)
+  is_published    Boolean  @default(false)
+  summary         String?  @db.Text
+  content         String?  @db.Text
+  constraints     Json?
+  hints           Json?
+  examples        Json?
+  languages       Json?
+  tags            Json?
+  change_summary  String?  @db.VarChar(500)
+  change_type     String   @default("update") @db.VarChar(20) // create, update, rollback
+  created_at      DateTime @default(now())
+  created_by      String?  @db.VarChar(40)
+
+  problem         Problem  @relation(fields: [problem_id], references: [id], onDelete: Cascade)
+
+  @@unique([problem_id, version_number])
+  @@index([problem_id])
+  @@index([created_at])
+  @@map("problem_versions")
+}
+
 model ProblemDetail {
   id                String   @id @db.VarChar(40)
   problem_id        BigInt   @unique
@@ -865,9 +906,10 @@ model Submission {
   test_details       Json?
   memoryDistBinsMb   Json?
   runtimeDistBinsMs  Json?
-  contestSubmissions ContestSubmission[]
-  problem            Problem             @relation(fields: [problem_id], references: [id], onDelete: Cascade)
-  user               User                @relation(fields: [user_id], references: [id], onDelete: Cascade)
+  contestSubmissions  ContestSubmission[]
+  executionLogs      SandboxExecutionLog[]
+  problem            Problem              @relation(fields: [problem_id], references: [id], onDelete: Cascade)
+  user               User                 @relation(fields: [user_id], references: [id], onDelete: Cascade)
 
   @@index([problem_id, user_id])
   @@index([created_at])
@@ -1306,3 +1348,59 @@ enum EmailStatus {
   SENT
   FAILED
 }
+
+// Sandbox Execution Monitoring
+model SandboxExecutionLog {
+  id              String              @id @default(uuid()) @db.VarChar(40)
+  execution_id    String              @unique @db.VarChar(40)
+  submission_id   String?             @db.VarChar(40)
+  language        String              @db.VarChar(20)
+  status          ExecutionStatus     @default(RUNNING)
+  time_ms         Int?
+  memory_bytes    Int?
+  exit_code       Int?
+  error_message   String?             @db.Text
+  container_id    String?             @db.VarChar(64)
+  started_at      DateTime            @default(now())
+  completed_at    DateTime?
+  created_at      DateTime            @default(now())
+
+  submission      Submission?         @relation(fields: [submission_id], references: [id])
+
+  @@index([status])
+  @@index([language])
+  @@index([started_at])
+  @@index([submission_id])
+  @@map("sandbox_execution_logs")
+}
+
+model SandboxMetrics {
+  id                   String    @id @default(uuid()) @db.VarChar(40)
+  date                 DateTime  @db.Date
+  total_executions     Int       @default(0)
+  successful           Int       @default(0)
+  timeouts             Int       @default(0)
+  memory_exceeded      Int       @default(0)
+  runtime_errors       Int       @default(0)
+  compile_errors       Int       @default(0)
+  system_errors        Int       @default(0)
+  avg_time_ms          Float?
+  max_time_ms          Int?
+  avg_memory_bytes     Float?
+  max_memory_bytes     Int?
+  created_at           DateTime  @default(now())
+  updated_at           DateTime  @updatedAt
+
+  @@unique([date])
+  @@map("sandbox_metrics")
+}
+
+enum ExecutionStatus {
+  RUNNING
+  COMPLETED
+  TIMEOUT
+  MEMORY_EXCEEDED
+  RUNTIME_ERROR
+  COMPILE_ERROR
+  SYSTEM_ERROR
+}