#!/usr/bin/env bash
# Build the GitHub Pages site: download the first STEP chunk of the ABC
# dataset, extract the first N models, gzip each file, and write an index.
#
# Env:
#   CHUNK_ARCHIVE  path to an already-downloaded abc_0000_step_v00.7z
#                  (skips the ~1.6 GB download)
#   WORK           working directory (default: ./build)
#   N              number of models to host (default: 1000)
set -euo pipefail

REPO_ROOT=$(cd "$(dirname "$0")/.." && pwd)
WORK=${WORK:-"$REPO_ROOT/build"}
N=${N:-1000}

mkdir -p "$WORK"
cd "$WORK"

# The name recorded in index.json always refers to the canonical source chunk.
CHUNK_NAME=abc_0000_step_v00.7z

# Mirror holding a repack of just the first 1000 model directories of the
# canonical chunk (byte-identical files). Used because archive.nyu.edu
# rate-limits by IP (mod_qos) and often redirects CI runners to an HTML
# restrictions page instead of serving the file.
MIRROR_URL=https://github.com/concept-collection/abc-step-1000/releases/download/data-v00/abc_0000_step_v00_first1000.7z

is_7z() { [ "$(head -c 2 "$1" 2> /dev/null)" = "7z" ]; }

if [ -z "${CHUNK_ARCHIVE:-}" ]; then
    wget -q https://deep-geometry.github.io/abc-dataset/data/step_v00.txt
    CHUNK_URL=$(sed '1q;d' step_v00.txt | awk '{print $1}')
    for attempt in 1 2 3; do
        echo "Downloading $CHUNK_NAME from $CHUNK_URL (attempt $attempt) ..."
        wget -q --no-check-certificate "$CHUNK_URL" -O chunk.7z || true
        is_7z chunk.7z && break
        echo "Response is not a 7z archive (rate-limited?); retrying in 30 s"
        sleep 30
    done
    if ! is_7z chunk.7z; then
        echo "Falling back to mirror: $MIRROR_URL"
        wget -q "$MIRROR_URL" -O chunk.7z
        is_7z chunk.7z
    fi
    CHUNK_ARCHIVE="$WORK/chunk.7z"
fi

# Extract only the first N model directories; the full chunk holds 10000
# models (~15 GB uncompressed), far more than we need or than CI disk allows.
echo "Extracting first $N model directories from $CHUNK_NAME ..."
seq -f '%08g/*' 0 $((N - 1)) > include.txt
rm -rf extracted
7z x -y "$CHUNK_ARCHIVE" -i@include.txt -oextracted > /dev/null

rm -rf site
mkdir -p site/step
find extracted -name '*.step' | sort | head -n "$N" > files.txt
echo "Compressing $(wc -l < files.txt) STEP files ..."
xargs -a files.txt -P "$(nproc)" -I{} \
    sh -c 'gzip -9 -c "$1" > "site/step/$(basename "$1").gz"' _ {}

python3 "$REPO_ROOT/scripts/make_index.py" files.txt site "$CHUNK_NAME"
cp "$REPO_ROOT/site/index.html" site/

echo "Done. Site size:"
du -sh site