#!/usr/bin/env bash
# ==============================================================================
# Help4 Network Property - Public License
# Find Large Files and Inodes
# Version 1.7.0
#
# TERMS OF USAGE:
# This script is FREE to use by end users.
#
# Commercial use is allowed ONLY if proper credit is preserved and shown when
# handing this script, its output, or a derived version to customers.
#
# Required commercial credit:
#   Phillip Ley - https://phillipley.com
#   Help4 Network - https://help4wordpress.com
#
# Do not remove this notice from redistributed copies.
# ==============================================================================

set -uo pipefail
export LC_ALL=C

VERSION="1.7.0"

TOP_FILES="${TOP_FILES:-10}"
LARGE_FILE_MB="${LARGE_FILE_MB:-100}"
LARGE_FILE_BYTES=$((LARGE_FILE_MB * 1024 * 1024))

GOOD_SIZE_LIMIT_GB="${GOOD_SIZE_LIMIT_GB:-25}"
GOOD_INODE_LIMIT="${GOOD_INODE_LIMIT:-100000}"

CHECK_SIZE_LIMIT_GB="${CHECK_SIZE_LIMIT_GB:-75}"
CHECK_INODE_LIMIT="${CHECK_INODE_LIMIT:-250000}"

REPORT_DIR="${REPORT_DIR:-/root}"
REPORT_TIMESTAMP="$(date '+%Y-%m-%d_%H-%M-%S')"
HOSTNAME_SHORT="$(hostname -s 2>/dev/null || hostname 2>/dev/null || echo server)"
REPORT_FILE="${REPORT_FILE:-${REPORT_DIR}/help4-large-files-inodes-report-${HOSTNAME_SHORT}-${REPORT_TIMESTAMP}.txt}"

EMAIL_FROM="${EMAIL_FROM:-root@${HOSTNAME_SHORT}}"
EMAIL_SUBJECT="${EMAIL_SUBJECT:-Help4 Network Large File and Inode Report - ${HOSTNAME_SHORT} - ${REPORT_TIMESTAMP}}"

TMP_ROOT="/tmp/h4-large-files-report.$$"

mkdir -p "$TMP_ROOT"
mkdir -p "$REPORT_DIR" 2>/dev/null || true

cleanup() {
    rm -rf "$TMP_ROOT"
}
trap cleanup EXIT

hr_bytes() {
    numfmt --to=iec --suffix=B "$1" 2>/dev/null || echo "${1}B"
}

line() {
    printf '%*s\n' "${COLUMNS:-100}" '' | tr ' ' '='
}

small_line() {
    printf '%*s\n' "${COLUMNS:-100}" '' | tr ' ' '-'
}

print_terms_full() {
    echo "TERMS OF USAGE:"
    echo "  This script is FREE to use by end users."
    echo
    echo "  Commercial use is allowed ONLY if proper credit is preserved and shown"
    echo "  when handing this script, its output, or a derived version to customers."
    echo
    echo "  Required commercial credit:"
    echo "    Phillip Ley - https://phillipley.com"
    echo "    Help4 Network - https://help4wordpress.com"
    echo
    echo "  Do not remove this notice from redistributed copies."
}

print_report_credit_header() {
    line
    echo "Help4 Network - Large File and Inode Report v${VERSION}"
    echo "Created by Phillip Ley / Help4 Network"
    echo "Phillip Ley: https://phillipley.com"
    echo "Help4 Network: https://help4wordpress.com"
    echo
    echo "Customer Report Notice:"
    echo "This report was generated using a free end-user tool created by Phillip Ley / Help4 Network."
    echo "Commercial providers may use this tool for customers only when this credit remains visible."
    echo
    echo "Report File:"
    echo "${REPORT_FILE}"
    echo
    echo "Generated:"
    date
    echo
    echo "Server:"
    hostname -f 2>/dev/null || hostname 2>/dev/null || echo "Unknown"
    line
}

print_report_credit_footer() {
    line
    echo "Report generated by Help4 Network - Large File and Inode Report v${VERSION}"
    echo "Tool credit: Phillip Ley (https://phillipley.com) / Help4 Network (https://help4wordpress.com)"
    echo "Free for end users. Commercial/customer use requires this visible credit in delivered reports."
    echo "Report file: ${REPORT_FILE}"
    line
}

show_help() {
    cat <<EOF
Help4 Network - Large File and Inode Report v${VERSION}

This script scans cPanel accounts and reports:
  - GOOD / CHECK / BAD account status
  - Account disk usage
  - Account inode usage
  - Filesystem inode pool usage
  - Top files over the configured size threshold
  - Top inode-heavy directories for accounts needing attention
  - Saves the final report to a TXT file
  - Offers to email the report using the WHM/cPanel server's local mail system

Environment overrides:
  TOP_FILES=10
  LARGE_FILE_MB=100
  GOOD_SIZE_LIMIT_GB=25
  GOOD_INODE_LIMIT=100000
  CHECK_SIZE_LIMIT_GB=75
  CHECK_INODE_LIMIT=250000

Report options:
  REPORT_DIR=/root
  REPORT_FILE=/root/custom-report-name.txt

Email options:
  EMAIL_FROM=root@server
  EMAIL_SUBJECT="Help4 Network Large File and Inode Report"

Examples:
  sudo ./find_large_files_and_inodes.sh
  sudo TOP_FILES=5 LARGE_FILE_MB=100 ./find_large_files_and_inodes.sh
  sudo REPORT_DIR=/home/user ./find_large_files_and_inodes.sh
  sudo REPORT_FILE=/root/customer-report.txt ./find_large_files_and_inodes.sh

EOF

    print_terms_full
}

get_cpanel_users() {
    if [ -d /var/cpanel/users ]; then
        find /var/cpanel/users -maxdepth 1 -type f -printf '%f\n' 2>/dev/null | sort
        return
    fi

    awk -F: '$6 ~ /^\/home[0-9]*\// && $3 >= 500 {print $1}' /etc/passwd | sort
}

get_user_home() {
    local user="$1"
    local cpanel_file="/var/cpanel/users/$user"
    local homedir=""

    if [ -f "$cpanel_file" ]; then
        homedir="$(awk -F= '$1=="HOMEDIR" {print $2; exit}' "$cpanel_file" 2>/dev/null || true)"
    fi

    if [ -z "$homedir" ]; then
        homedir="$(getent passwd "$user" 2>/dev/null | awk -F: '{print $6}')"
    fi

    if [ -n "$homedir" ] && [ -d "$homedir" ]; then
        echo "$homedir"
    fi
}

get_account_size_bytes() {
    local homedir="$1"
    du -sx -B1 "$homedir" 2>/dev/null | awk '{print $1}'
}

get_account_inode_count() {
    local homedir="$1"

    find "$homedir" -xdev \
        \( \
            -path "$homedir/virtfs" -o -path "$homedir/virtfs/*" \
            -o -path "$homedir/.cagefs" -o -path "$homedir/.cagefs/*" \
            -o -path "$homedir/.trash" -o -path "$homedir/.trash/*" \
        \) -prune \
        -o -printf '.' 2>/dev/null | wc -c
}

print_filesystem_inode_usage() {
    local homedir="$1"

    df -Pi "$homedir" 2>/dev/null | awk 'NR==2 {
        printf "Filesystem inode pool: used=%s available=%s total=%s usage=%s mounted_on=%s\n", $3, $4, $2, $5, $6
    }'
}

get_large_files() {
    local homedir="$1"
    local outfile="$2"

    find "$homedir" -xdev \
        \( \
            -path "$homedir/virtfs" -o -path "$homedir/virtfs/*" \
            -o -path "$homedir/.cagefs" -o -path "$homedir/.cagefs/*" \
            -o -path "$homedir/.trash" -o -path "$homedir/.trash/*" \
        \) -prune \
        -o -type f -size +"${LARGE_FILE_BYTES}c" -printf '%s\t%p\n' 2>/dev/null \
        | sort -k1,1nr \
        | head -n "$TOP_FILES" > "$outfile"
}

print_large_files() {
    local filelist="$1"

    if [ -s "$filelist" ]; then
        echo "Top ${TOP_FILES} files over ${LARGE_FILE_MB}MB:"
        numfmt --to=iec --suffix=B --field=1 --delimiter=$'\t' < "$filelist" 2>/dev/null || cat "$filelist"
    else
        echo "Large files: none over ${LARGE_FILE_MB}MB"
    fi
}

print_inode_hotspots() {
    local homedir="$1"

    echo "Top inode-heavy directories:"
    find "$homedir" -xdev \
        \( \
            -path "$homedir/virtfs" -o -path "$homedir/virtfs/*" \
            -o -path "$homedir/.cagefs" -o -path "$homedir/.cagefs/*" \
            -o -path "$homedir/.trash" -o -path "$homedir/.trash/*" \
        \) -prune \
        -o -type f -printf '%h\n' 2>/dev/null \
        | sort \
        | uniq -c \
        | sort -nr \
        | head -n 10 \
        | awk '{count=$1; $1=""; sub(/^ /,""); printf "%8d files\t%s\n", count, $0}'
}

classify_account() {
    local size_bytes="$1"
    local inode_count="$2"
    local large_count="$3"

    local good_size_bytes=$((GOOD_SIZE_LIMIT_GB * 1024 * 1024 * 1024))
    local check_size_bytes=$((CHECK_SIZE_LIMIT_GB * 1024 * 1024 * 1024))

    if [ "$large_count" -eq 0 ] && [ "$size_bytes" -lt "$good_size_bytes" ] && [ "$inode_count" -lt "$GOOD_INODE_LIMIT" ]; then
        echo "GOOD"
        return
    fi

    if [ "$size_bytes" -ge "$check_size_bytes" ] || [ "$inode_count" -ge "$CHECK_INODE_LIMIT" ]; then
        echo "BAD"
        return
    fi

    echo "CHECK"
}

print_account_report() {
    local user="$1"
    local homedir="$2"

    local account_size_bytes="0"
    local account_inode_count="0"
    local large_file_list="$TMP_ROOT/${user}.largefiles"
    local large_file_count="0"
    local status="CHECK"

    account_size_bytes="$(get_account_size_bytes "$homedir")"
    account_size_bytes="${account_size_bytes:-0}"

    account_inode_count="$(get_account_inode_count "$homedir")"
    account_inode_count="${account_inode_count:-0}"

    get_large_files "$homedir" "$large_file_list"
    large_file_count="$(wc -l < "$large_file_list" 2>/dev/null | tr -d ' ')"
    large_file_count="${large_file_count:-0}"

    status="$(classify_account "$account_size_bytes" "$account_inode_count" "$large_file_count")"

    small_line
    echo "Account: $user"
    echo "Home:    $homedir"
    echo "Status:  $status"

    echo
    echo "Disk used by account:       $(hr_bytes "$account_size_bytes")"
    echo "Inodes used by account:     $account_inode_count"
    print_filesystem_inode_usage "$homedir"

    echo
    print_large_files "$large_file_list"

    if [ "$status" = "GOOD" ]; then
        echo
        echo "Result: Account appears normal. No files over ${LARGE_FILE_MB}MB and inode/disk usage are within normal thresholds."
    else
        echo
        print_inode_hotspots "$homedir"
    fi
}

generate_report() {
    local users_file="$TMP_ROOT/users.list"
    local total_users="0"
    local scanned_users="0"
    local skipped_users="0"
    local user=""
    local homedir=""

    print_report_credit_header

    echo "Scan Settings:"
    echo "Large file threshold:       ${LARGE_FILE_MB}MB"
    echo "Top files per account:      ${TOP_FILES}"
    echo "GOOD disk limit:            ${GOOD_SIZE_LIMIT_GB}GB"
    echo "GOOD inode limit:           ${GOOD_INODE_LIMIT}"
    echo "BAD disk threshold:         ${CHECK_SIZE_LIMIT_GB}GB"
    echo "BAD inode threshold:        ${CHECK_INODE_LIMIT}"

    get_cpanel_users > "$users_file"

    total_users="$(wc -l < "$users_file" 2>/dev/null | tr -d ' ')"
    total_users="${total_users:-0}"

    echo "Detected cPanel users:      $total_users"

    while IFS= read -r user || [ -n "$user" ]; do
        [ -n "$user" ] || continue

        homedir="$(get_user_home "$user" || true)"

        if [ -z "$homedir" ]; then
            skipped_users=$((skipped_users + 1))
            small_line
            echo "Account: $user"
            echo "Status:  SKIPPED"
            echo "Reason:  No valid home directory found."
            continue
        fi

        scanned_users=$((scanned_users + 1))
        print_account_report "$user" "$homedir"
    done < "$users_file"

    line
    echo "Summary"
    line
    echo "Detected users: $total_users"
    echo "Scanned users:  $scanned_users"
    echo "Skipped users:  $skipped_users"
    echo

    print_report_credit_footer
    echo
    echo "Report complete."
}

send_report_with_sendmail() {
    local to="$1"

    if [ ! -x /usr/sbin/sendmail ]; then
        return 1
    fi

    {
        echo "From: ${EMAIL_FROM}"
        echo "To: ${to}"
        echo "Subject: ${EMAIL_SUBJECT}"
        echo "MIME-Version: 1.0"
        echo "Content-Type: text/plain; charset=UTF-8"
        echo "Content-Disposition: inline"
        echo
        cat "$REPORT_FILE"
    } | /usr/sbin/sendmail -t

    return $?
}

send_report_with_mailx() {
    local to="$1"

    if command -v mailx >/dev/null 2>&1; then
        mailx -r "$EMAIL_FROM" -s "$EMAIL_SUBJECT" "$to" < "$REPORT_FILE"
        return $?
    fi

    if command -v mail >/dev/null 2>&1; then
        mail -r "$EMAIL_FROM" -s "$EMAIL_SUBJECT" "$to" < "$REPORT_FILE"
        return $?
    fi

    return 1
}

email_report_prompt() {
    local answer=""
    local to=""
    local send_status="1"

    if [ ! -s "$REPORT_FILE" ]; then
        echo "Email skipped: report file does not exist or is empty."
        return 1
    fi

    if [ ! -t 0 ]; then
        echo "Email prompt skipped because this is not an interactive terminal."
        echo "Report saved to: $REPORT_FILE"
        return 0
    fi

    echo
    line
    echo "Email Report"
    line
    echo "Report saved to:"
    echo "$REPORT_FILE"
    echo
    echo "Would you like to email this report using this WHM/cPanel server's local mail system?"
    printf "Email report now? [y/N]: "
    read -r answer

    case "$answer" in
        y|Y|yes|YES|Yes)
            ;;
        *)
            echo "Email skipped."
            return 0
            ;;
    esac

    printf "Send report to email address: "
    read -r to

    if [ -z "$to" ]; then
        echo "Email skipped: no recipient entered."
        return 1
    fi

    echo "Sending report to: $to"

    if send_report_with_sendmail "$to"; then
        echo "Email sent using /usr/sbin/sendmail."
        return 0
    fi

    if send_report_with_mailx "$to"; then
        echo "Email sent using mail/mailx."
        return 0
    fi

    echo "Email failed: no working local sendmail, mailx, or mail command was available."
    echo "Report remains saved at: $REPORT_FILE"
    return 1
}

main() {
    case "${1:-}" in
        -h|--help|help)
            show_help
            exit 0
            ;;
    esac

    if ! touch "$REPORT_FILE" 2>/dev/null; then
        echo "Could not write to report file:"
        echo "$REPORT_FILE"
        echo
        echo "Try running as root or set REPORT_DIR/REPORT_FILE."
        echo "Example:"
        echo "  sudo REPORT_DIR=/root ./find_large_files_and_inodes.sh"
        exit 1
    fi

    : > "$REPORT_FILE"

    generate_report | tee "$REPORT_FILE"

    echo
    echo "TXT report saved to:"
    echo "$REPORT_FILE"

    email_report_prompt
}

main "$@"