#!/bin/bash
#
# Common functions.
#

# Setup main configuration and load preferences
function keyringer_config_load {
  if [ -f "$HOME/.$NAME" ]; then
    echo "Converting legacy configuration scheme..."
    mv "$HOME/.$NAME" "$HOME/.$NAME.tmp"
    mkdir "$HOME/.$NAME"
    mv "$HOME/.$NAME.tmp" "$CONFIG"
  fi

  if [ ! -e "$CONFIG" ]; then
    echo "Creating $CONFIG..."
    mkdir -p `dirname $CONFIG`
    touch "$CONFIG"
    chmod 600 "$CONFIG"
    echo "# Keyringer config file." > "$CONFIG"
    echo "" >> "$CONFIG"
  fi

  keyringer_config_load_preferences
}

# Load config preferences
function keyringer_config_load_preferences {
  # Load custom keyring preferences
  if [ ! -z "$PREFERENCES" ] && [ -f "$PREFERENCES" ]; then
    source "$PREFERENCES"
  fi
}

# Load a parameter from config
function keyringer_config {
  if [ -z "$CONFIG" ]; then
    echo "Your have to set CONFIG variable in the code"
    exit 1
  elif [ -e "$CONFIG" ]; then
    grep -e "^$1=" "$CONFIG" | tail -n 1 | cut -d = -f 2 | sed -e 's/"//g' -e "s/'//g" | sed -e 's/ *#.*$//'
  else
    echo "Config file not found: $CONFIG"
    exit 1
  fi
}

# Return the list of recipients
function keyringer_recipients {
  grep -v '^#' "$1" | grep -v '^$' | awk '{ print "-r " $2 }' | xargs
}

# Check if keyringer has a given action
function keyringer_has_action {
 if [ -z "$ACTIONS" ]; then
   echo "Your have to set ACTIONS variable in the code"
   exit 1
 fi

 if [ -e "$ACTIONS/$1" ]; then
   true
 else
   false
 fi
}

# Execute an action
function keyringer_exec {
  # Setup
  action="$1"
  basedir="$2"
  shift 2
  
  # Dispatch
  if keyringer_has_action "$action"; then
    "$ACTIONS/$action" "$basedir" $*
  fi
}

# Return a filename with correct extension
function keyringer_filename {
  if [ -z "$1" ]; then
    return
  else
    printf "%s/%s.asc\n" "$(dirname "$1")" "$(basename "$1" .asc)"
  fi
}

# Check if a folder is inside a git repository
function keyringer_is_git {
  if [ -z "$1" ]; then
    false
  elif [ ! -d "$1" ]; then
    false
  elif [ -d "$1/.git" ]; then
    true
  else
    cwd="`pwd`"
    cd "$1" && git="`git status &> /dev/null`" && cd "$cwd"

    if [ "$git" != "128" ]; then
      true
    else
      false
    fi
  fi
}

# Setup a temporary file
function keyringer_set_tmpfile {
  if [ -z "$BASEDIR" ]; then
    echo "Please set BASEDIR before creating a tmp file"
    exit 1
  fi

  if [ -z "$1" ]; then
    template="$BASEDIR/tmp/keyringer.XXXXXXXXXX"
  else
    template="$BASEDIR/tmp/$1.XXXXXXXXXX"
  fi

  mkdir -p "$BASEDIR/tmp"
  keyringer_git_ignore 'tmp/*'

  if [ "$2" == "-d" ]; then
    TMPWORK="$(mktemp -d "$template")"
  else
    TMPWORK="$(mktemp "$template")"
  fi
  
  if [ "$?" != "0" ]; then
    printf "Error: can't set TMPWORK %s\n" "$TMPWORK"
    exit 1
  fi

  trap "keyringer_unset_tmpfile $TMPWORK; exit" INT TERM EXIT
}

# Remove a temporary file
function keyringer_unset_tmpfile {
  if [ -z "$1" ]; then
    echo "No tmp file set"
  fi

  rm -f "$1"

  if [ "$?" != "0" ]; then
    echo "Warning: could not delete file $1. Please delete it manually as it might have sensitive information."
    exit 1
  fi
}

# Add a pattern into gitignore
function keyringer_git_ignore {
  if [ ! -z "$BASEDIR/.gitignore" ]; then
    echo "$1" > "$BASEDIR/.gitignore"
    keyringer_exec git "$BASEDIR" add .gitignore
  else
    if ! grep -q -e "^$1$" "$BASEDIR/.gitignore"; then
      echo "$1" >> "$BASEDIR/.gitignore"
    fi
  fi
}

# Set needed environment variables and do basic checks.
function keyringer_set_env {
  if [ -z "$1" ]; then
    echo "Error: missing arguments for keyringer_set_env"
    exit 1    
  fi

  ACTIONS="`dirname $0`"
  BASENAME="`basename $0`"
  BASEDIR="$1"
  SUBCOMMAND="$2"
  KEYDIR="$BASEDIR/keys"
  RECIPIENTS="$BASEDIR/config/recipients"
  OPTIONS="$BASEDIR/config/options"
  VERSION_INFO="$BASEDIR/config/version"

  if [ -z "$BASEDIR" ]; then
    keyringer_action_usage
    exit 1
  fi

  if [ ! -f "$RECIPIENTS" ]; then
    echo "No recipient config was found"
    exit 1
  fi

  if [ -z "$EDITOR" ]; then
    if type sensible-editor > /dev/null 2>&1 ; then
      EDITOR=sensible-editor
    elif type editor > /dev/null 2>&1 ; then
      EDITOR=editor
    else
      echo "You have to set EDITOR env variable"
      exit 1
    fi
  fi

  if [ ! -f "$OPTIONS" ]; then
    echo "No option config was found"
    exit 1
  fi

  if [ ! -z "$KEYID" ]; then
    GPG="gpg -u $KEYID"
  else
    GPG="gpg"
  fi

  # Check recipients file
  keyringer_check_recipients $SUBCOMMAND

  # Ensure that keydir exists
  mkdir -p "$KEYDIR" && chmod 700 "$KEYDIR"

  # Check keyring config version
  keyringer_check_version
}

# Configuration version tracking to help keyring upgrades
function keyringer_check_version {
  if [ ! -f "$VERSION_INFO" ]; then
    echo "Creating configuration version file..."
    echo 0 > "$VERSION_INFO"
    keyringer_exec git "$BASEDIR" add config/version
  fi

  VERSION="`cat $VERSION_INFO`"
}

# Get a file argument
function keyringer_get_file {
  FILE="$(keyringer_filename "$1")"
  
  if [ -z "$FILE" ]; then
    keyringer_action_usage
    exit 1
  elif [ ! -f "$KEYDIR/$FILE" ]; then
    echo "File not found: $KEYDIR/$FILE"
    exit 1
  fi
}

# Get a new file argument
function keyringer_get_new_file {
  FILE="$(keyringer_filename "$1")"
  
  if [ -z "$FILE" ]; then
    keyringer_action_usage
    exit 1
  fi
}

# Get a command argument
function keyringer_get_command {
  # Aditional parameters
  COMMAND="$1"
  
  if [ -z "$COMMAND" ]; then
    keyringer_action_usage command
    exit 1
  fi
}

# Run the action usage
function keyringer_action_usage {
  if [ "`type -t "keyringer_usage_$BASENAME"`" == "function" ]; then
    # Use custom action usage
    "keyringer_usage_$BASENAME"
  else
    # Default usage
    if [ "$1" == "command" ]; then
      echo "Usage: keyringer <keyring> $BASENAME <command> [arguments]"
    else
      echo "Usage: keyringer <keyring> $BASENAME <file>"
    fi
  fi
}

# Check recipients
function keyringer_check_recipients {
  # Check recipients header for updates.
  if grep -qe ' XXXXXXXX$' "$RECIPIENTS"; then
    echo "Updating recipients file..."
    sed -i -e 's/ XXXXXXXX$/ XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX/' "$RECIPIENTS"
  fi

  if [ "$1" == "edit" ]; then
    # Don't do the other checks at edit mode.
    return
  fi

  for recipient in $(cat "$RECIPIENTS" | grep -v '^#' | awk '{ print $2 }'); do
    size=$(echo "$recipient" | wc -c)
    if (( $size < 41 )); then
      echo "Fatal: please set the full GPG signature hash for key ID $recipient:"
      cat <<-EOF

Recipients file can't have 32-bit keyids (e.g.  DEADBEEF or DECAF123).  These
are trivial to spoof.  With a few gigs of disk space and a day of time on
cheap, readily-available hardware, it's possible to build keys to match every
possible 32-bit keyid.  The search space just isn't big enough.

If you're going to specify keys by keyid, they should be specified by full
160-bit OpenPGP fingerprint.  It would be very bad if someone spoofed a keyID
and caused another participant in a keyringer instance to reencrypt a secret
store to the spoofed key in addition to your own.
EOF
      exit 1
    else
      gpg --list-key "$recipient" &> /dev/null
      if [ "$?" != "0" ]; then
        echo "Fatal: no such key $recipient on your GPG keyring."
        echo "Please check for this key or fix the recipient file."
        exit 1
      fi
    fi
  done
}

# Setup environment
if [ "$(basename "$0")" != "keyringer" ]; then
  keyringer_set_env $*
fi