#!/bin/bash
# AgentCheckin CGI entry for fnOS.
# - serves static files from the app's www directory
# - /api/* requests are dispatched to the Python backend (api.py)
#
# Installed layout (see fnOS app framework docs):
#   /var/apps/AgentCheckin/target/ui/index.cgi      (this file)
#   /var/apps/AgentCheckin/target/app/backend       (python backend)
#   /var/apps/AgentCheckin/target/app/www           (static files)
#   /vol{n}/@appdata/AgentCheckin                   (TRIM_PKGVAR: persistent data)

SCRIPT_DIR="$(cd "$(dirname "$0")" 2>/dev/null && pwd)"
APP_ROOT="${SCRIPT_DIR}/.."
BASE_PATH="${APP_ROOT}/www"
BACKEND_DIR="${APP_ROOT}/backend"

# fnOS CGI processes carry no TRIM_PKGVAR. Resolve the persistent data dir
# (@appdata/AgentCheckin) and export it explicitly so the Python backend and
# the scheduler daemon always agree on one location.
if [ -n "${TRIM_PKGVAR}" ] && [ -d "${TRIM_PKGVAR}" ]; then
    export AGENTCHECKIN_DATA_DIR="${TRIM_PKGVAR}"
else
    for _cand in \
        "${APP_ROOT}/../../@appdata/AgentCheckin" \
        "/var/apps/AgentCheckin/var" \
        "/vol1/@appdata/AgentCheckin" \
        "/vol2/@appdata/AgentCheckin"; do
        if [ -d "$_cand" ]; then
            export AGENTCHECKIN_DATA_DIR="$_cand"
            break
        fi
    done
fi

# Resolve a python3 interpreter: prefer the fnOS runtime dependency app.
PYBIN=""
for candidate in \
    /var/apps/python312/target/bin/python3 \
    /var/apps/python311/target/bin/python3 \
    /var/apps/python310/target/bin/python3 \
    /usr/bin/python3 \
    /usr/local/bin/python3; do
    if [ -x "$candidate" ]; then PYBIN="$candidate"; break; fi
done

json_error() {
    # $1 = http status body, $2 = message
    printf 'Status: %s\r\n' "$1"
    printf 'Content-Type: application/json; charset=utf-8\r\n'
    printf 'Cache-Control: no-store\r\n'
    printf '\r\n'
    printf '{"error":"%s"}\n' "$2"
    exit 0
}

# ---------------------------------------------------------------------------
# Parse the relative request path (everything after "index.cgi")
# ---------------------------------------------------------------------------
URI_NO_QUERY="${REQUEST_URI%%\?*}"
REL_PATH="/"
case "$URI_NO_QUERY" in
    *index.cgi*)
        REL_PATH="${URI_NO_QUERY#*index.cgi}"
        ;;
esac
REL_PATH="${REL_PATH#/}"
REL_PATH="${REL_PATH%/}"

# ---------------------------------------------------------------------------
# API requests -> python backend
# ---------------------------------------------------------------------------
case "$REL_PATH" in
    api/*)
        if [ -z "$PYBIN" ]; then
            json_error "500 Internal Server Error" "python3 runtime unavailable"
        fi
        if [ ! -f "${BACKEND_DIR}/api.py" ]; then
            json_error "500 Internal Server Error" "backend missing"
        fi
        export AGENTCHECKIN_BACKEND_DIR="$BACKEND_DIR"
        exec "$PYBIN" "${BACKEND_DIR}/api.py"
        ;;
esac

# ---------------------------------------------------------------------------
# Static files (with path-traversal protection)
# ---------------------------------------------------------------------------
if [ -z "$REL_PATH" ] || [ "$REL_PATH" = "/" ]; then
    REL_PATH="index.html"
fi

case "$REL_PATH" in
    *..*) json_error "400 Bad Request" "bad path" ;;
esac
OLD_IFS="$IFS"
IFS='/'
for SEG in $REL_PATH; do
    case "$SEG" in
        ''|.|*[!A-Za-z0-9._-]*) IFS="$OLD_IFS"; json_error "400 Bad Request" "bad path" ;;
    esac
done
IFS="$OLD_IFS"

TARGET_FILE="${BASE_PATH}/${REL_PATH}"
if [ ! -f "$TARGET_FILE" ]; then
    json_error "404 Not Found" "not found"
fi

case "${TARGET_FILE##*.}" in
    html|htm) mime="text/html; charset=utf-8" ;;
    css)      mime="text/css; charset=utf-8" ;;
    js)       mime="application/javascript; charset=utf-8" ;;
    json)     mime="application/json; charset=utf-8" ;;
    png)      mime="image/png" ;;
    jpg|jpeg) mime="image/jpeg" ;;
    gif)      mime="image/gif" ;;
    svg)      mime="image/svg+xml" ;;
    ico)      mime="image/x-icon" ;;
    webmanifest) mime="application/manifest+json" ;;
    txt)      mime="text/plain; charset=utf-8" ;;
    woff)     mime="font/woff" ;;
    woff2)    mime="font/woff2" ;;
    *)        mime="application/octet-stream" ;;
esac

printf 'Content-Type: %s\r\n' "$mime"
printf 'Cache-Control: no-cache\r\n'
printf '\r\n'
cat "$TARGET_FILE"
exit 0