#!/usr/bin/env bash

function main() {
  shopt -s nullglob # * returns nothing for empty directory

  # ansi escape codes for color output
  local GREEN='\033[32m'
  local YELLOW='\033[33m'
  local BLUE='\033[34m'
  local RED='\033[31m'
  local RESET='\033[0m'
  
  # Files uploaded to serv-u
  local SERVU_BASE="/mnt/os-transfer"
  local IMPORT_DIR="$SERVU_BASE/space-landing/Import"
  local EXPORT_DIR="$SERVU_BASE/space-landing/Export"
  local LIN_DIR="/mnt/linux"
  local WIN_DIR="/mnt/windows"

  cd "/opt/os-transfer" || { echo "Cannot cd to /opt/os-transfer"; exit; }

  local SPACE_PROJECT_MAP="./space-project-map"
  [[ -f "$SPACE_PROJECT_MAP" ]] || \
  { 
    logging::debug "Missing: $SPACE_PROJECT_MAP"
    exit 1
  }

  local SPACE_DOMAINS_FILE="./space-domains.txt"
  [[ -f "$SPACE_DOMAINS_FILE" ]] || \
  { 
    logging::debug "Missing: $SPACE_DOMAINS_FILE"
    exit 1
  }

  local SPACE_EMAIL_FILE="/tmp/space-email"

  local EMAIL_ARCHIVE="."
  [[ -d "/opt/os-transfer/emails" ]] && {
    local EMAIL_ARCHIVE="/opt/os-transfer/emails"
  }

  local LOG_DIR="."
  [[ -d "/opt/os-transfer/log" ]] && {
    local LOG_DIR="/opt/os-transfer/log"
  }
  local TODAY_FAILURES="$LOG_DIR/failure.log"
  local TODAY_INGRESS="$LOG_DIR/ingress.log"
  local TODAY_EGRESS="$LOG_DIR/egress.log"

  while [[ $# -gt 0 ]]; do
    case "$1" in
      -m|--email)
        run_email=true
        ;;
      -p|--purge)
        run_purge=true
        ;;
      -e|--export)
        run_export=true
        ;;
      -i|--import)
        run_import=true
        ;;
      -h|--help)
        echo "Usage: script.sh [-m|--email] [-p|--purge] [-e|--export] [-i|--import]"
        exit 0
        ;;
      -*)
        echo "Unknown option: $1" >&2
        exit 1
        ;;
      *)
        echo "Ignoring unexpected argument: $1" >&2
        ;;
    esac
    shift
  done

  # Execute actions in desired order
  [[ $run_import ]] && transfer::import
  [[ $run_export ]] && transfer::export
  [[ $run_purge  ]] && purge_files
  [[ $run_email  ]] && email

  exit 0
}

function transfer::import() {
  echo -e "${BLUE}Importing Files...${RESET}"

  for filepath in "$IMPORT_DIR"/*; do
    [[ -f "$filepath" ]] || continue # Regular file
    [[ -L "$filepath" ]] && continue # Skip Symlinks
    [[ -d "$filepath" ]] && continue # Skip Directory

    local file=${filepath##*/} # strip directories from path

    # ensure file has correct format
    if [[ ! "$file" =~ ^eidf[a-zA-Z0-9]{2,5}-[a-zA-Z0-9]{3,8}-.+$ ]]; then
      logging::failure "[IMPORT] $file — Filename format invalid"
      continue
    fi

    # Ensure filename matches expected format
    if [[ ! "$file" =~ ^eidf[a-zA-Z0-9]{2,5}-[a-zA-Z0-9]{3,8}-.+ ]]; then
      logging::failure "[IMPORT] $file — Filename format invalid"
      continue
    fi


    # example file: eidf123-abc01-file.csv
    local project="${file%%-*}"             # eidf123
    local rest="${file#*-}"                 # abc01-file.csv
    local study="${rest%%-*}"               # abc01
    local filename="${rest#*-}"             # file.csv

    # fail if any variable are empty
    if [[ -z "$project" || -z "$study" || -z "$filename" ]]; then
      logging::failure "[IMPORT] $file — Filename format invalid"
      continue
    fi

    #echo "File '$filename' in project $project for study $study"

    local pattern="/mnt/*/$project*"
    local matching_projects
    mapfile -t matching_projects < <(compgen -G "$pattern")

    case ${#matching_projects[@]} in
      0)
        logging::failure "[IMPORT] $file — $project does not exist"
        continue
        ;;
      1)
        local project_mount="${matching_projects[0]}"
        ;;
      *)
        logging::failure "[IMPORT] $file — $project exists in multiple locations"
        continue
        ;;
    esac

    check_mtitme "import" "$filepath" || continue

    local sha256
    read -r sha256 _ < <(sha256sum "$filepath") 

    # Extracts Windows/Linux from $project_mount and sets the 'environment' vairable
    # This changes the moving path depending if window or Linux
    # /mnt/windows/eidfsp02-sgstd
    local environment="${project_mount#/mnt/}"  # windows/eidfsp02-sgstd
    local environment="${environment%%/*}"      # windows

    if [[ $environment == "windows" ]]; then
      # Check destination directory exists
      [[ -d "$project_mount/Import/$study" ]] || { 
        logging::failure "[IMPORT] $file — $study project does not exist"
        continue
      }

      logging::move "[IMPORT] $file ===> $project_mount/Import/$study"
      mv "$filepath" "$project_mount/Import/$study"
      logging::transfer "import" "sha256:$sha256 — $file" "$TODAY_INGRESS"

    elif [[ $environment == "linux" ]]; then
      # Check destination directory exists
      [[ -d "$project_mount/Import/" ]] || { 
        logging::failure "[IMPORT] $file — $project does not exist"
        continue
      }

      logging::move "[IMPORT] $file ==MOVE==> $project_mount/Import/"
      mv "$filepath" "$project_mount/Import/"

    else
      logging::failure "[IMPORT] $file — Environment could not be identified"
    fi
  done
}

function transfer::export() {
  echo -e "${BLUE}Exporting Files...${RESET}"

  # LINUX EXPORT

  for filepath in "$LIN_DIR"/*/Export/*; do
    [[ -f "$filepath" ]] || continue # Regular file
    [[ -L "$filepath" ]] && continue # Skip Symlinks
    [[ -d "$filepath" ]] && continue # Skip Directory

    local file=${filepath##*/}

    local project="${filepath#/mnt/linux/}"
    local project="${project%%/Export/*}"

    local zone
    local lookup_key="$project"
    while read -r key value; do
      if [[ "$key" == "$lookup_key" ]]; then
        zone="$value"
        break
      fi
    done < "$SPACE_PROJECT_MAP"

    [[ -z "$zone" ]] && {
      logging::failure "[EXPORT] $filepath — $project has not been mapped to standard or protected"
      continue
    }

    check_mtitme "export" "$filepath" || continue

    new_filename="$zone-$project-$file"
    logging::debug "[EXPORT] $filepath ==RENAME==> $new_filename"

    read -r sha256 _ < <(sha256sum "$filepath")
    logging::transfer "export" "sha256:$sha256 — $file" "$TODAY_EGRESS"

    logging::move "[EXPORT] $file ==MOVE==> $EXPORT_DIR/$new_filename"
    mv "$filepath" "$EXPORT_DIR/$new_filename"
    chgrp "$project" "$EXPORT_DIR/$new_filename"
    chmod 664 "$EXPORT_DIR/$new_filename"
  done

  # WINDOWS EXPORT

  readarray -t SPACE_WINDOWS_DOMAINS < "$SPACE_DOMAINS_FILE"

  for filepath in "$WIN_DIR"/*/Export/*/*; do
    [[ -f "$filepath" ]] || continue # Regular file
    [[ -L "$filepath" ]] && continue # Skip Symlinks
    [[ -d "$filepath" ]] && continue # Skip Directory
    local file=${filepath##*/}

    local base="${filepath#/mnt/windows/}"
    local study="${base#*/Export/}"
    local study="${study%%/"$file"}"
    local project="${base%%/Export/*}"
    # local eidf_project="${project%%-*}"

    # Check that windows environment is in domain list
    [[ ! " ${SPACE_WINDOWS_DOMAINS[*]} " =~ (^|[[:space:]])$project([[:space:]]|$) ]] && {
      logging::failure "[EXPORT] $project is not in windows domain list"
    }

    check_mtitme "export" "$filepath" || continue

    local zone
    local lookup_key="$project"
    while read -r key value; do
      if [[ "$key" == "$lookup_key" ]]; then
        zone="$value"
        break
      fi
    done < "$SPACE_PROJECT_MAP"

    [[ -z "$zone" ]] && {
      logging::failure "[EXPORT] $filepath — $project has not been mapped to standard or protected"
      continue
    }

    new_filename="$zone-$project-$study-$file"
    logging::debug "[EXPORT] $filepath ==RENAME==> $new_filename"

    read -r sha256 _ < <(sha256sum "$filepath")
    logging::transfer "export" "sha256:$sha256 — $file" "$TODAY_EGRESS"

    if [[ "$file" == mft-* ]]; then
      logging::move "[EXPORT] $filepath ==MOVE==> /mnt/os-transfer/windows-mft/$project/$study/Export/$new_filename"
      mv "$filepath" "$SERVU_BASE/windows-mft/$project/$study/Export/$new_filename" 
    else
      logging::move "[EXPORT] $filepath ==MOVE==> $EXPORT_DIR/$new_filename"
      mv "$filepath" "$EXPORT_DIR/$new_filename"
      chmod 774 "$EXPORT_DIR/$new_filename"
    fi
  done
}

function logging::transfer() {
  local action=$1
  local log_line=$2
  local log_file=$3

  # Create log file if missing
  [[ -f "$log_file" ]] || : > "$log_file" 

  # Always print to terminal
  echo -e "${GREEN}[${action^^}] ${log_line}${RESET}"

  # Append to file only if the exact line isn't already logged
  if ! grep -qxF "$log_line" "$log_file"; then
    echo "$log_line" >> "$log_file"
  fi
}

function logging::failure() {
  local log_line="$1"

  # Create log file if missing
  [[ -f "$TODAY_FAILURES" ]] || : > "$TODAY_FAILURES" 

  # Always print to terminal
  echo -e "${RED}${log_line}${RESET}"

  # Append to file only if the exact line isn't already logged
  if ! grep -qxF "$log_line" "$TODAY_FAILURES"; then
    echo "$log_line" >> "$TODAY_FAILURES"
  fi
}

function logging::move() { echo -e "${YELLOW}$1${RESET}"; }
function logging::debug() { echo -e "${BLUE}$1${RESET}"; }

function check_mtitme() {
    local action=$1
    local filepath=$2
    local threshold=3
    if find "$filepath" -mmin -"$threshold" | grep -q .; then
      logging::debug "[${action^^}] $file — file has been modified in last $(( threshold * 60 )) seconds"
      return 1
    fi
}

function purge_files() {
  logging::debug "[PRUGE] Removing files older than two weeks"
  for filepath in "$IMPORT_DIR"/*; do
    #local file=${filepath##*/}
    if find "$filepath" -mtime +14 | grep -q .; then
      logging::move "[PURGE] Deleting $filepath"
      rm "$filepath"
    fi
  done
}

function email() {
  local SUBJECT="Space Openstack File Transfer"
  local MAIL_FROM="hpcsys-bayes@epcc.ed.ac.uk"
  local RCPT_TO="hpcsys-bayes@epcc.ed.ac.uk r.davies@epcc.ed.ac.uk analytical.workbench@gov.scot a.brown@epcc.ed.ac.uk"

  : > "$SPACE_EMAIL_FILE"

  # Build email
  {
    echo "Subject: $SUBJECT"
    echo "From: $MAIL_FROM"
    echo

    if [[ ! -s "$TODAY_EGRESS" ]] && [[ ! -s "$TODAY_INGRESS" ]]; then
      echo "No files transferred within the last day."
      echo
    else
      if [[ -s "$TODAY_EGRESS" ]]; then
        echo "Files exported in the last day"
        echo "---------------------------------"
        cat "$TODAY_EGRESS"
        echo
      else echo "No files exported in the last day"; echo
      fi

      if [[ -s "$TODAY_INGRESS" ]]; then
        echo "Files Imported in the last day"
        echo "---------------------------------"
        cat "$TODAY_INGRESS"
        echo
      else echo "No files imported in the last day"; echo
      fi
    fi

    if [[ -s "$TODAY_FAILURES" ]]; then
      echo "File Transfer Failures in the last day"
      echo "---------------------------------"
      cat "$TODAY_FAILURES"
      echo
    fi
  } >> "$SPACE_EMAIL_FILE"

  sendmail "$RCPT_TO" < "$SPACE_EMAIL_FILE"

  : > "$TODAY_INGRESS"
  : > "$TODAY_EGRESS"
  : > "$TODAY_FAILURES"
  mv "$SPACE_EMAIL_FILE" "$EMAIL_ARCHIVE/$(date +%Y-%m-%d)-space-email"
}

main "$@"