#!/usr/bin/env bash
# Documentation: render the diagrams, and serve the pages from a throwaway nginx container.
# Usage: docs.sh serve | graphs
# Whose: DOCS_DIR, the docs/ of the folder `make docs` runs from (a project's launcher sets
# it); unset, rig's own.
# Notes: docs/notes/docs.md
set -euo pipefail
cd "$(dirname "$0")"

source ./lib/config.sh
load_config

REPO="$(cd .. && pwd)"
DOCS="${DOCS_DIR:-$REPO/docs}"
[ -d "$DOCS" ] && DOCS="$(cd "$DOCS" && pwd)"
DOCS_PORT="${DOCS_PORT:-$((HTTP_PORT + 4))}"   # +4 sits inside this env's block

serve() {
    if [ ! -f "$DOCS/index.html" ]; then
        echo "no index.html in $DOCS" >&2
        exit 1
    fi
    # One worker and no access log: a few static pages need no more, and the
    # terminal then shows only real errors. The config is a temp file, gone on exit.
    # nginx runs as the caller, not as its own user: it reads what the caller can read,
    # whatever the umask (a 027 one leaves files unreadable to "others", which is a 403).
    # So no port below 1024 inside, and pid and temp files go to /tmp.
    # Global, not local: the trap runs after serve() has returned.
    DOCS_CONF=$(mktemp)
    trap 'rm -f "$DOCS_CONF"' EXIT
    cat > "$DOCS_CONF" <<'NGINX'
worker_processes 1;
error_log stderr error;
pid /tmp/nginx.pid;
events { worker_connections 64; }
http {
    include /etc/nginx/mime.types;
    access_log off;
    client_body_temp_path /tmp/client_body;
    proxy_temp_path /tmp/proxy;
    fastcgi_temp_path /tmp/fastcgi;
    uwsgi_temp_path /tmp/uwsgi;
    scgi_temp_path /tmp/scgi;
    server { listen 8080; root /usr/share/nginx/html; }
}
NGINX
    chmod 644 "$DOCS_CONF"
    echo "docs of $DOCS"
    echo "  for '$CLUSTER' on http://localhost:${DOCS_PORT}"
    echo "  (ctrl-c to stop; nothing is installed and nothing persists)"
    docker run --rm \
        --name "${CLUSTER}-docs" \
        --user "$(id -u):$(id -g)" \
        --entrypoint nginx \
        -p "${DOCS_PORT}:8080" \
        -v "$DOCS:/usr/share/nginx/html:ro" \
        -v "$DOCS_CONF:/etc/nginx/nginx.conf:ro" \
        nginx:alpine -g 'daemon off;'
}

graphs() {
    if ! command -v dot >/dev/null 2>&1; then
        echo "graphviz not found — install with: sudo apt install graphviz" >&2
        echo "(only needed to re-render; the committed .svg files already work)" >&2
        exit 1
    fi
    shopt -s nullglob
    local found=0 f out
    for f in "$DOCS"/graphs/*.dot; do
        out="${f%.dot}.svg"
        echo "  graphviz $(basename "$f") → $(basename "$out")"
        dot -Tsvg "$f" -o "$out"
        found=1
    done
    [ "$found" -eq 1 ] || echo "  no .dot files in $DOCS/graphs/"
}

case "${1:-serve}" in
    serve)  serve ;;
    graphs) graphs ;;
    *)      echo "usage: $0 [serve|graphs]" >&2; exit 1 ;;
esac