# ────────────────
# Stage 1: Builder
# ────────────────
FROM python:3.10-slim AS builder

# Install build dependencies
RUN apt-get update && apt-get install -y \
    build-essential \
    gcc \
    g++ \
    pkg-config \
    libmupdf-dev \
    && rm -rf /var/lib/apt/lists/*

# Upgrade pip and install wheel
RUN pip install --upgrade pip setuptools wheel

# Create virtual environment
RUN python -m venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"

# Copy requirements and install dependencies
WORKDIR /build
COPY requirements.txt .

# Install Python packages
RUN pip install --no-cache-dir -r requirements.txt

# ────────────────
# Stage 2: Production
# ────────────────
FROM python:3.10-slim

# Install runtime dependencies
RUN apt-get update && apt-get install -y \
    poppler-utils \
    tesseract-ocr \
    tesseract-ocr-eng \
    tesseract-ocr-fas \
    mupdf-tools \
    libmupdf-dev \
    ffmpeg \
    libopencv-dev \
    libgl1-mesa-dri \
    libglib2.0-0 \
    libsm6 \
    libxext6 \
    libxrender-dev \
    libgomp1 \
    libgbm1 \
    libxss1 \
    libgtk-3-0 \
    libxtst6 \
    libxrandr2 \
    libasound2 \
    libpangocairo-1.0-0 \
    libatk1.0-0 \
    libcairo-gobject2 \
    libgdk-pixbuf-2.0-0 \
    libffi-dev \
    libssl-dev \
    curl \
    wget \
    sqlite3 \
    && rm -rf /var/lib/apt/lists/* \
    && apt-get clean

# Create non-root user
RUN groupadd -g 1000 appuser && useradd -r -u 1000 -g appuser appuser

# Copy virtual environment from builder
COPY --from=builder /opt/venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"

# Set working directory
WORKDIR /app

# Copy all files
COPY --chown=appuser:appuser . .

# Pre-download TrOCR model to speed up startup
RUN python -c "from transformers import TrOCRProcessor, VisionEncoderDecoderModel; \
    TrOCRProcessor.from_pretrained('microsoft/trocr-base-printed'); \
    VisionEncoderDecoderModel.from_pretrained('microsoft/trocr-base-printed')" || echo "Model download failed, will download at runtime"

# Environment variables
ENV PYTHONPATH=/app
ENV TRANSFORMERS_CACHE=/app/cache
ENV HF_HOME=/app/cache
ENV LOG_LEVEL=INFO
ENV ENVIRONMENT=production
ENV PYTHONUNBUFFERED=1

# Switch to non-root user
USER appuser

# Expose port
EXPOSE 7860

# Healthcheck
HEALTHCHECK --interval=45s --timeout=30s --start-period=180s --retries=10 \
    CMD python -c "import requests; requests.get('http://localhost:7860')" || exit 1

# Start Gradio app (not FastAPI)
CMD ["python", "app.py"]