#!/bin/bash
# Render a 3D model to 2D sprites at 3 resolutions from 4 cardinal directions.
# Usage: render.sh <model_name> [godot_path]
# Example: render.sh wall_structural
set -euo pipefail

MODEL_NAME="${1:?Usage: render.sh <model_name> [godot_path]}"
GODOT="${2:-$HOME/bin/godot}"
REPO_ROOT="$(cd "$(dirname "$0")" && git rev-parse --show-toplevel)"
PROJECT="$REPO_ROOT/renderer"
SCENE="res://render_scene.tscn"
OUTPUT="$PROJECT/output"

# Verify model exists
MODEL_FILE="$PROJECT/models/${MODEL_NAME}.tscn"
if [ ! -f "$MODEL_FILE" ]; then
    echo "ERROR: Model not found: $MODEL_FILE"
    echo "Available models:"
    ls "$PROJECT/models/"*.tscn 2>/dev/null | xargs -I{} basename {} .tscn
    exit 1
fi

echo "Rendering: $MODEL_NAME"
echo "Godot: $GODOT"
echo "Project: $PROJECT"

# The render step (unlike --import) needs a display. Fail fast with a clear
# remedy instead of letting Godot die on a cryptic low-level GL/X error.
if [ -z "${DISPLAY:-}" ]; then
    if command -v xvfb-run >/dev/null 2>&1; then
        echo "No DISPLAY set — re-run under xvfb-run, e.g.:"
        echo "  xvfb-run -a $0 $MODEL_NAME${2:+ $2}"
        exit 1
    else
        echo "ERROR: No DISPLAY set and xvfb-run is not installed."
        echo "  Install it (e.g. 'xorg-x11-server-Xvfb' on Fedora/RHEL, 'xvfb' on"
        echo "  Debian/Ubuntu), then re-run under xvfb-run -a."
        exit 1
    fi
fi

# Ensure resources are imported (headless, no display needed)
echo "Importing resources..."
"$GODOT" --path "$PROJECT" --headless --import 2>&1 || echo "Warning: import step had errors (may be non-fatal)"

# Clear stale output from any previous run of this model first, so a failed
# render can't be masked by leftover files from an earlier successful run.
rm -f "$OUTPUT/${MODEL_NAME}"_*.png

# Run Godot with the render scene, passing model name as user arg
"$GODOT" --path "$PROJECT" "$SCENE" -- "$MODEL_NAME" 2>&1

# Check output
FOUND_FILES=0
for dir in north east south west; do
    for res in 1024 256 64; do
        f="$OUTPUT/${MODEL_NAME}_${dir}_${res}.png"
        if [ -f "$f" ]; then
            FOUND_FILES=$((FOUND_FILES + 1))
        fi
    done
done

echo ""
echo "Generated $FOUND_FILES/12 files in $OUTPUT/"
ls -la "$OUTPUT/${MODEL_NAME}"_*.png 2>/dev/null || echo "No output files found."

if [ "$FOUND_FILES" -eq 0 ]; then
    echo "ERROR: Godot produced no output files — render failed." >&2
    exit 1
fi