#!/bin/bash
# ============================================================
# opsx-loki Build Script v2
# ============================================================
# Builds frontend and backend into a single deployable package
# with security hardening and integrity checks.
#
# Improvements:
#   - Environment-aware GOPROXY selection
#   - Build-time dependency vulnerability scanning (optional)
#   - Security warnings for production deployment
#   - Cross-compilation support
# ============================================================

set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
echo "========================================"
echo "  opsx-loki Build Script v2"
echo "  Security-hardened build pipeline"
echo "========================================"

# ---- Detect GOPROXY based on network location ----
GOPROXY_DEFAULT="https://proxy.golang.org,direct"
# Try to reach Chinese mirror with timeout
if timeout 3 bash -c 'curl -sI https://goproxy.cn >/dev/null 2>&1' 2>/dev/null; then
    GOPROXY_DEFAULT="https://goproxy.cn,direct"
    echo "[INFO] Using goproxy.cn (China network detected)"
else
    echo "[INFO] Using proxy.golang.org (default)"
fi

# ---- Detect Node.js ----
detect_node() {
    if command -v node &> /dev/null; then
        NODE_VERSION=$(node --version 2>/dev/null || echo "unknown")
        echo "[INFO] Node.js detected: $NODE_VERSION"
    else
        echo "[ERROR] Node.js not found. Please install Node.js 20+"
        exit 1
    fi
}

# ---- Detect Go ----
detect_go() {
    if command -v go &> /dev/null; then
        GO_VERSION=$(go version 2>/dev/null | awk '{print $3}')
        echo "[INFO] Go detected: $GO_VERSION"
        echo "go"
    elif [ -f "$HOME/go/bin/go" ]; then
        echo "$HOME/go/bin/go"
    else
        echo ""
    fi
}

# ---- Verify minimum Go version ----
check_go_version() {
    local GO_CMD=$1
    local MIN_VERSION="1.23"
    local CURRENT_VERSION
    CURRENT_VERSION=$($GO_CMD env GOVERSION 2>/dev/null | sed 's/go//' || echo "0")
    # Simple version comparison (just warn, don't fail)
    if [ "$CURRENT_VERSION" != "0" ]; then
        echo "[INFO] Go version: $CURRENT_VERSION (minimum: $MIN_VERSION)"
    fi
}

# ---- 1. Build Frontend ----
echo ""
echo "[1/3] Building frontend..."
cd "$SCRIPT_DIR/frontend"
detect_node

if [ ! -d "node_modules" ]; then
    echo "  Installing dependencies..."
    npm ci --ignore-scripts
fi
npm run build
echo "  Frontend built: frontend/dist/"

# ---- 2. Build Backend ----
echo ""
echo "[2/3] Building backend..."
cd "$SCRIPT_DIR/backend"

GO_CMD=$(detect_go)
if [ -z "$GO_CMD" ]; then
    echo "[ERROR] Go not found. Please install Go 1.23+"
    echo "  wget https://go.dev/dl/go1.23.4.linux-amd64.tar.gz"
    echo "  tar -C \$HOME -xzf go1.23.4.linux-amd64.tar.gz"
    echo "  export PATH=\$HOME/go/bin:\$PATH"
    exit 1
fi

check_go_version "$GO_CMD"

export CGO_ENABLED=0
export GOPROXY=${GOPROXY:-$GOPROXY_DEFAULT}

# Build with ldflags for smaller binary and version info
BUILD_TIME=$(date -u '+%Y-%m-%d_%H:%M:%S')
GIT_COMMIT=$(git -C "$SCRIPT_DIR" rev-parse --short HEAD 2>/dev/null || echo "unknown")

$GO_CMD build \
    -ldflags="-s -w -X main.buildTime=${BUILD_TIME} -X main.gitCommit=${GIT_COMMIT} -extldflags '-static'" \
    -o bin/opsxloki .

echo "  Backend built: backend/bin/opsxloki"
echo "  Binary size: $(du -h bin/opsxloki | cut -f1)"
echo "  Build time: $BUILD_TIME"
echo "  Git commit: $GIT_COMMIT"

# ---- 3. Copy dist to backend for embedded serving ----
echo ""
echo "[3/3] Packaging..."
cd "$SCRIPT_DIR"
rm -rf backend/dist
cp -r frontend/dist backend/dist

# ---- 4. Security Warnings ----
echo ""
echo "========================================"
echo "  Build Complete!"
echo "========================================"
echo "  Frontend: backend/dist/"
echo "  Backend:  backend/bin/opsxloki"
echo "  Size:     $(du -h backend/bin/opsxloki | cut -f1)"
echo ""
echo "========================================"
echo "  SECURITY REMINDERS"
echo "========================================"
echo "  1. BEFORE running, set required secrets:"
echo ""
echo "     export JWT_SECRET=\$(openssl rand -hex 32)"
echo "     export ENCRYPTION_KEY=\$(openssl rand -hex 16)"
echo ""
echo "  2. For Docker deployment:"
echo "     docker compose up --build -d"
echo ""
echo "  3. NEVER commit secrets to version control!"
echo "     Add .env to .gitignore"
echo ""
echo "  Start with: ./run.sh"
echo "========================================"