#!/bin/sh

# Download and merge lists of Gemini hosts from:
# gemini://geminispace.info/known-hosts
# gemini://gemini.bortzmeyer.org/software/lupa/lupa-capsules.txt
# gemini://auragem.space/search/capsules

set -o errexit  # (-e) exit immediately if any command has a non-zero exit status
set -o nounset  # (-u) don't accept undefined variables
#set -o xtrace  # for debugging

timestamp_start=$(date +%s)

# Go where this script is.
cd "$(dirname "$0")" || exit

hosts1=$(agunua --binary --maximum-time 20 \
  gemini://geminispace.info/known-hosts 2>/dev/null \
  | grep "gemini://" | cut -d ' ' -f 3)
if [ -z "$hosts1" ]; then
  >&2 echo "geminispace.info/known-hosts download failed."
  exit 1
fi
hosts2=$(agunua --binary --maximum-time 20 \
  gemini://gemini.bortzmeyer.org/software/lupa/lupa-capsules.txt 2>/dev/null)
if [ -z "$hosts2" ]; then
  >&2 echo "lupa-capsules.txt download failed."
  exit 1
fi
#hosts3=$(agunua --binary --maximum-time 20 \
#  gemini://auragem.space/search/capsules 2>/dev/null \
#  | grep "gemini://" | cut -d ' ' -f 2 | cut -d '/' -f 3)
#if [ -z "$hosts3" ]; then
#  >&2 echo "geminispace.info/known-hosts download failed."
#  exit 1
#fi

# Concatenate hosts files.
hosts="$hosts1
$hosts2"
#$hosts3"

# Remove empty lines; convert punycode to unicode; sort entries; remove duplicates.
hosts=$(echo "$hosts" | awk NF | idn --allow-unassigned --idna-to-unicode | sort -fu)

# Remove hosts which contain neither "." nor ":", such as "localhost".
hosts=$(echo "$hosts" | grep '\.\|:')

# Remove explicitly excluded hosts.
hosts=$(echo "$hosts" | grep -vxEf excluded-hosts)

if ! echo "$hosts" | grep -qE '\.onion(:.*)?$'; then
  >&2 echo "The .onions are missing!"
  exit 1
fi

if [ -z "$hosts" ]; then
  >&2 echo "hosts file downloads failed."
  exit 1
fi

# Save to temporary file.
tempfile=$(mktemp)
echo "$hosts" > "$tempfile"

# Delete temporary file on exit.
finish() {
  rm -f "$tempfile"
}
trap finish EXIT

# Check connection to host.
# $1: "" or "tor"
# $2: host[:port]
test_host() {
  host="$2"
  tor=""
  if [ "$1" = "tor" ]; then
    tor="--socks 127.0.0.1:9050"
  fi
  agunua $tor --no-tofu --accept-expired-certificate --ignore-missing-tls-close \
    --maximum-time 20 "gemini://$host/" >/dev/null 2>&1
}

# Test if removed hosts are still online.
if [ -f hosts ]; then
  echo "Testing removed hosts..."
  for removed_host in $(diff hosts "$tempfile" | grep ^\< | cut -c 3-); do
    printf "%s" "$removed_host"
    # If direct connection fails, try to connect through Tor.
    if test_host "" "$removed_host" || test_host "tor" "$removed_host"; then
      echo " - ONLINE"
      # Add removed host back.
      hosts="$hosts
$removed_host"
    else
      echo " - offline"
    fi
  done
fi

# Sort entries again.
hosts=$(echo "$hosts" | sort)

# Save to file.
echo "$hosts" > hosts

timestamp_end=$(date +%s)
exec_time="$((timestamp_end - timestamp_start))"
exec_time_formatted="$(date -d "@$exec_time" --utc "+%H:%M:%S")"

echo "OK (duration: $exec_time_formatted)"