#!/bin/bash
# Postfix Mail Summary Tool - Hardened & Domain-Focused Version (v2026.1.1)

# ==============================================================================
# 1. RESOURCE LIMITS & ENVIRONMENT
# ==============================================================================
ulimit -t 15
ulimit -v 500000
ulimit -f 102400

set -euo pipefail
IFS=$'\n\t'

# ==============================================================================
# 2. LOCKFILE & PRE-FLIGHT CHECKS
# ==============================================================================
# Lockfile fallback if /var/lock is not writable
LOCKFILE="/var/lock/postfix_summary.lock"
[ -w /var/lock ] || LOCKFILE="/tmp/postfix_summary.lock"

exec 9>>"$LOCKFILE"
if ! flock -n 9; then
    echo "Error: Another instance is already running." >&2
    exit 1
fi

TMP_DATA=$(mktemp /tmp/postfix_log.XXXXXX)
trap 'rm -f "$TMP_DATA" 2>/dev/null' EXIT

export USE_COLOR=0
[[ -t 1 ]] && USE_COLOR=1
readonly USE_COLOR

# ==============================================================================
# 3. HELP MENU
# ==============================================================================
show_help() {
    echo "Usage: $0 [OPTIONS]"
    echo ""
    echo "Options:"
    echo "  -h, --help                Display this help message"
    echo "  -l, --list NUMBER          Number of records to show (1-1000, default: 10)"
    echo "  -f, --from EMAIL/DOMAIN    Filter by sender address"
    echo "  -t, --to EMAIL/DOMAIN      Filter by recipient address"
    echo "  -i, --id QUEUE_ID          Search for a specific ID (Detail View)"
    echo "  -d, --date \"MMM DD\"        Filter by date (e.g., \"Mar 27\")"
    echo "                            Use \"\" to search through all available logs"
    exit 0
}

# ==============================================================================
# 4. ARGUMENT PARSING
# ==============================================================================
LIMIT=10; readonly MAX_LIMIT=1000; readonly MAX_INPUT_LEN=100
FROM_FILTER=""; TO_FILTER=""; ID_FILTER=""; DATE_FILTER=""; DATE_SET=0

check_arg() {
    local opt="$1"
    shift
    if [[ "$#" -lt 1 ]]; then
        echo "Error: Option '$opt' requires an argument (can be \"\")." >&2
        exit 1
    fi
}

sanitize() {
    echo "${1:0:$MAX_INPUT_LEN}" | tr -cd '[:alnum:]@._ -'
}

while [[ "$#" -gt 0 ]]; do
    case $1 in
        -h|--help) show_help ;;
        -l|--list) check_arg "$1" "${2:-}"; if [[ "$2" =~ ^[0-9]+$ ]]; then LIMIT="$2"; fi; shift ;;
        -f|--from) check_arg "$1" "${2:-}"; FROM_FILTER=$(sanitize "${2:-}"); shift ;;
        -t|--to)   check_arg "$1" "${2:-}"; TO_FILTER=$(sanitize "${2:-}"); shift ;;
        -i|--id)   check_arg "$1" "${2:-}"; ID_FILTER=$(sanitize "${2:-}"); shift ;;
        -d|--date) 
            if [[ "$#" -lt 2 ]]; then echo "Error: Option '$1' requires an argument."; exit 1; fi
            DATE_FILTER=$(sanitize "${2:-}"); DATE_SET=1; shift ;;
        *) echo "Unknown option: $1" >&2; exit 1 ;;
    esac
    shift
done

# Limit validation
(( LIMIT < 1 )) && LIMIT=1
(( LIMIT > MAX_LIMIT )) && LIMIT=$MAX_LIMIT

if [ "$DATE_SET" -eq 0 ]; then DATE_FILTER=$(date '+%b %e'); fi
readonly DATE_FILTER
DETAIL_VIEW=0; [[ -n "$ID_FILTER" && "$ID_FILTER" != "NOQUEUE" ]] && DETAIL_VIEW=1

# ==============================================================================
# 5. LOG FILE DISCOVERY
# ==============================================================================
LOG_FILES=()
while IFS= read -r -d '' file; do LOG_FILES+=("$file"); done < <(find /var/log -maxdepth 1 -name 'maillog*' -type f -print0 2>/dev/null | sort -z -r)
[ ${#LOG_FILES[@]} -eq 0 ] && { echo "Error: No Postfix logs found." >&2; exit 1; }

# ==============================================================================
# 6. LOG PROCESSING (AWK ENGINE)
# ==============================================================================
process_logs() {
    for log in "${LOG_FILES[@]}"; do
        [ ! -r "$log" ] && continue
        if [[ "$log" =~ \.gz$ ]]; then
            gzip -t "$log" 2>/dev/null && zcat -- "$log"
        else
            cat -- "$log"
        fi
    done
}

process_logs | awk -v d_filt="$DATE_FILTER" -v f_filt="$FROM_FILTER" -v t_filt="$TO_FILTER" -v i_filt="$ID_FILTER" '
BEGIN { 
    split("Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec", n); 
    for(i in n) { m[n[i]]=sprintf("%02d",i); months[n[i]]=1; }
    db_count = 0;
}
!($1 in months) { next }
{ if (length($0) < 20 || length($0) > 2048) next; }
(d_filt != "" && substr($0, 1, length(d_filt)) != d_filt) { next }
{
    if (db_count > 100000) { split("", db_from); split("", db_time); split("", db_in_ip); db_count = 0; }
    qid = ""; for(i=1; i<=9; i++) if($i ~ /^[A-F0-9]+:$/) { qid=$i; gsub(/:/,"",qid); break; }
    curr_t = $1"-"$2"_"$3;
    if (qid != "" && !(qid in db_from)) { db_count++; }
    if (index($0, "amavis") > 0 && index($0, "queued_as:") > 0) {
        match($0, /queued_as: [A-F0-9]+/); aqid = substr($0, RSTART+11, RLENGTH-11);
        if (match($0, /\[[0-9]{1,3}\.[0-9.]+/)) db_in_ip[aqid] = substr($0, RSTART+1, RLENGTH-1);
    }
    if (qid != "" && index($0, "client=") > 0) {
        if (match($0, /\[[0-9]{1,3}\.[0-9.]+/)) {
            cip = substr($0, RSTART+1, RLENGTH-1);
            if (cip != "127.0.0.1" && db_in_ip[qid] == "") db_in_ip[qid] = cip;
        }
        db_time[qid] = curr_t;
    }
    if (qid != "" && index($0, "from=<") > 0) {
        match($0, /from=<[^>]*>/); if (RLENGTH > 0) db_from[qid] = substr($0, RSTART+6, RLENGTH-7);
    }
    if (qid != "" && index($0, "to=<") > 0 && index($0, "status=") > 0) {
        if (index($0, "relay=127.0.0.1") > 0 || index($0, "10025") > 0) next;
        match($0, /to=<[^>]*>/); s_to = substr($0, RSTART+4, RLENGTH-5);
        match($0, /status=[a-z]+/); s_st = substr($0, RSTART+7, RLENGTH-7);
        rip = ""; if (match($0, /relay=[^ ]+\[[0-9]{1,3}\.[0-9.]+/)) {
            temp_m = substr($0, RSTART, RLENGTH); match(temp_m, /\[[0-9.]+/); rip = substr(temp_m, RSTART+1, RLENGTH-1);
        }
        final_ip = (rip != "" && rip != "127.0.0.1") ? rip : (db_in_ip[qid] != "" ? db_in_ip[qid] : "local");
        s_re = "OK"; if (match($0, /\([^)]*\)/)) { s_re = substr($0, RSTART+1, RLENGTH-2); gsub(/ /,"_",s_re); }
        s_f = (db_from[qid] != "") ? db_from[qid] : "-";
        s_tm = (db_time[qid] != "") ? db_time[qid] : curr_t;
        if ((f_filt == "" || index(s_f, f_filt) > 0) && (t_filt == "" || index(s_to, t_filt) > 0) && (i_filt == "" || index(qid, i_filt) > 0)) {
            sort_k = m[$1] sprintf("%02d", $2); tm_tmp=$3; gsub(/:/,"",tm_tmp); sort_k = sort_k tm_tmp;
            print sort_k " " s_tm " " qid " " final_ip " " s_f " " s_to " " s_st " " s_re;
        }
    }
    if (index($0, "NOQUEUE: reject:") > 0 && (i_filt == "" || i_filt == "NOQUEUE")) {
         match($0, /from=<[^>]*>/); f=(RLENGTH>0)?substr($0, RSTART+6, RLENGTH-7):"-";
         match($0, /to=<[^>]*>/); t=(RLENGTH>0)?substr($0, RSTART+4, RLENGTH-5):"-";
         if (match($0, /\[[0-9]{1,3}\.[0-9.]+/)) nip = substr($0, RSTART+1, RLENGTH-1); else nip = "unknown";
         s_st = (index($0, "Greylisted") > 0) ? "GREYLIST" : "REJECT";
         s_re = "Rejected"; if (match($0, /: [^;]+; /)) s_re = substr($0, RSTART+2, RLENGTH-4); gsub(/ /,"_",s_re);
         sort_k = m[$1] sprintf("%02d", $2); tm_tmp=$3; gsub(/:/,"",tm_tmp); sort_k = sort_k tm_tmp;
         if ((f_filt == "" || index(f, f_filt) > 0) && (t_filt == "" || index(t, t_filt) > 0)) {
            print sort_k " " curr_t " NOQUEUE " nip " " f " " t " " s_st " " s_re;
         }
    }
}' > "$TMP_DATA"

# ==============================================================================
# 7. FINAL OUTPUT RENDERING
# ==============================================================================
if [[ "$DETAIL_VIEW" -eq 1 ]]; then
    if [ ! -s "$TMP_DATA" ]; then echo "No records found for ID: $ID_FILTER"; exit 0; fi
    sort -n "$TMP_DATA" | awk -v u_col="$USE_COLOR" '{ 
        blue=(u_col=="1"?"\033[1;34m":""); reset=(u_col=="1"?"\033[0m":"");
        tm=$2; gsub(/_/," ",tm); qid=$3; ip=$4; 
        f=$5; gsub(/[^[:print:]]/, "", f);
        t=$6; gsub(/[^[:print:]]/, "", t);
        st=$7; 
        r=$8; gsub(/[^[:print:]]/, "", r); gsub(/_/," ",r); 
        printf "\n%s--- Detail for ID: %s ---%s\nDate: %s\nExternal IP: %s\nFrom: %s\nTo: %s\nStatus: %s\nReason: %s\n", blue,qid,reset,tm,ip,f,t,st,r 
    }'
else
    [[ "$USE_COLOR" -eq 1 ]] && printf "\033[1m"
    printf "%-16s %-12s %-16s %-36s %-31s %-12s %s\n" "DATE-TIME" "QUEUE_ID" "EXT_IP" "SENDER" "RECIPIENT" "STATUS" "REASON"
    [[ "$USE_COLOR" -eq 1 ]] && printf "\033[0m"

    sort -n "$TMP_DATA" | tail -n "$LIMIT" | awk -v u_col="$USE_COLOR" '
    function d_cut(e, m) { if(length(e)<=m)return e; return ".." substr(e, length(e)-m+2); }
    BEGIN { b="\033[1;34m"; r="\033[0m"; g="\033[1;32m"; rd="\033[1;31m"; y="\033[1;33m"; gr="\033[0;90m"; c="\033[0;36m"; if(u_col!="1")b=r=g=rd=y=gr=c=""; }
    {
        tm=$2; gsub(/_/," ",tm); id=$3; ip=$4; 
        from=$5; gsub(/[^[:print:]]/, "", from);
        to=$6; gsub(/[^[:print:]]/, "", to);
        st=$7; 
        re_f=$8; gsub(/[^[:print:]]/, "", re_f); gsub(/_/," ",re_f);
        re = (match(re_f, /[0-9]{3} [0-9]\.[0-9]\.[0-9]/)) ? substr(re_f, RSTART, RLENGTH) : substr(re_f, 1, 15);
        scol = (st == "sent") ? g : (st == "deferred" || st == "GREYLIST" ? y : rd);
        printf "%-16s %s%-12s%s %s%-16s%s %-36s %-31s %s%-12s%s %s[%s]%s\n", tm, (id=="NOQUEUE"?rd:b), id, r, gr, sprintf("%.15s", ip), r, d_cut(from, 35), d_cut(to, 30), scol, st, r, (st=="sent"?c:scol), re, r;
    }'
fi