#!/bin/bash
# -----------------------------------------------------------------------------------------------
# --------------------------------- Bandwidth Monitor ------------------------------------------
# -----------------------------------------------------------------------------------------------
# Logs daily rsync transfer totals and generates weekly summary reports.
# Designed for minimal flash drive impact — one bounded write per day.
#
# Two modes:
#   --log-transfer "profile" bytes duration  — called by rsync.sh after each sync
#                                              appends one line, trims old entries
#   --report                                 — generates weekly summary from log
#   (no args)                                — generates summary report
#
# Log format (one line per transfer):
#   YYYY-MM-DD|profile|bytes|duration_seconds
#
# Log file stays bounded to BANDWIDTH_LOG_RETENTION days — old entries trimmed on write.
# Minimal writes: one append per rsync run, one trim per append.
#
# All configuration in Master.conf under Bandwidth Monitor section.
# -----------------------------------------------------------------------------------------------

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

source "$SCRIPT_DIR/../Master.conf"
source "$SCRIPT_DIR/../common.sh"

parse_args "$@"

# Check for log-transfer mode
LOG_TRANSFER_MODE=false
REPORT_MODE=false
TRANSFER_PROFILE=""
TRANSFER_BYTES=0
TRANSFER_DURATION=0

for arg in "${PARSED_ARGS[@]}"; do
    case "$arg" in
        --log-transfer) LOG_TRANSFER_MODE=true ;;
        --report)       REPORT_MODE=true ;;
        *)
            if [[ "$LOG_TRANSFER_MODE" == true && -z "$TRANSFER_PROFILE" ]]; then
                TRANSFER_PROFILE="$arg"
            elif [[ "$LOG_TRANSFER_MODE" == true && "$TRANSFER_BYTES" -eq 0 ]]; then
                TRANSFER_BYTES="$arg"
            elif [[ "$LOG_TRANSFER_MODE" == true ]]; then
                TRANSFER_DURATION="$arg"
            fi
            ;;
    esac
done

# Ensure log file exists
touch "$BANDWIDTH_LOG" 2>/dev/null || {
    error "Cannot create bandwidth log: $BANDWIDTH_LOG"
    exit 1
}

# -----------------------------------------------------------------------------------------------
# LOG TRANSFER MODE
# Called by rsync.sh after each successful sync — appends one line and trims old entries
# Usage: bandwidth_monitor.sh --log-transfer "profile" bytes duration
# -----------------------------------------------------------------------------------------------
if [[ "$LOG_TRANSFER_MODE" == true ]]; then
    TODAY=$(date '+%Y-%m-%d')
    echo "${TODAY}|${TRANSFER_PROFILE}|${TRANSFER_BYTES}|${TRANSFER_DURATION}" >> "$BANDWIDTH_LOG"
    log "Logged transfer: $TRANSFER_PROFILE — $TRANSFER_BYTES bytes in ${TRANSFER_DURATION}s"

    # Trim entries older than retention period — keeps file bounded
    CUTOFF=$(date -d "${BANDWIDTH_LOG_RETENTION} days ago" '+%Y-%m-%d')
    TEMP_FILE="${BANDWIDTH_LOG}.tmp"
    awk -F'|' -v cutoff="$CUTOFF" '$1 >= cutoff' "$BANDWIDTH_LOG" > "$TEMP_FILE"
    mv "$TEMP_FILE" "$BANDWIDTH_LOG"
    log "Log trimmed — keeping entries from $CUTOFF onwards"
    exit 0
fi

# -----------------------------------------------------------------------------------------------
# REPORT MODE — generate summary from log
# -----------------------------------------------------------------------------------------------
echo ""
echo "━━━ $ICON_BANDWIDTH Bandwidth Report — $(date '+%Y-%m-%d %H:%M:%S') ━━━"
echo ""

if [[ ! -s "$BANDWIDTH_LOG" ]]; then
    warn "No bandwidth data yet — log is empty"
    warn "Data accumulates as rsync jobs run"
    exit 0
fi

START=$(date +%s)

# Calculate date range in log
OLDEST=$(awk -F'|' 'NR==1{print $1}' "$BANDWIDTH_LOG")
NEWEST=$(awk -F'|' 'END{print $1}' "$BANDWIDTH_LOG")
ENTRY_COUNT=$(wc -l < "$BANDWIDTH_LOG")

info "Log covers: $OLDEST → $NEWEST ($ENTRY_COUNT entries)"
echo ""

# Total bytes transferred
TOTAL_BYTES=$(awk -F'|' '{sum += $3} END {print sum+0}' "$BANDWIDTH_LOG")
TOTAL_GB=$(awk "BEGIN {printf \"%.2f\", $TOTAL_BYTES / 1073741824}")

# Per-profile breakdown
echo "━━━ $ICON_BANDWIDTH Per-Profile Totals ━━━"
awk -F'|' '{
    bytes[$2] += $3
    runs[$2]++
    duration[$2] += $4
}
END {
    for (profile in bytes) {
        gb = bytes[profile] / 1073741824
        printf "  %-20s %6.2f GB  (%d runs)\n", profile, gb, runs[profile]
    }
}' "$BANDWIDTH_LOG" | sort -k3 -rn

echo ""

# Daily totals for the last 7 days
echo "━━━ $ICON_BANDWIDTH Last 7 Days ━━━"
for i in 6 5 4 3 2 1 0; do
    day=$(date -d "$i days ago" '+%Y-%m-%d')
    day_bytes=$(awk -F'|' -v d="$day" '$1==d{sum+=$3} END{print sum+0}' "$BANDWIDTH_LOG")
    day_gb=$(awk "BEGIN {printf \"%.2f\", $day_bytes / 1073741824}")

    # Flag days that exceeded warning threshold
    over_warn=$(awk "BEGIN {print ($day_bytes > $BANDWIDTH_WARN_GB * 1073741824) ? 1 : 0}")
    if [[ "$over_warn" == "1" ]]; then
        echo "  $ICON_WARN  $day  ${day_gb} GB  ← exceeded ${BANDWIDTH_WARN_GB}GB threshold"
    else
        echo "  $ICON_TIME  $day  ${day_gb} GB"
    fi
done

echo ""
echo "━━━ $ICON_SUMMARY Totals ━━━"
echo "  $ICON_BANDWIDTH Total transferred: ${TOTAL_GB} GB"
echo "  $ICON_TIME      Log period:        $OLDEST → $NEWEST"
echo "  $ICON_GEAR      Retention:         ${BANDWIDTH_LOG_RETENTION} days"

END=$(date +%s)

echo ""
echo "━━━━━ $ICON_SUMMARY BANDWIDTH SUMMARY ━━━━━"
echo "$ICON_BANDWIDTH Total:    ${TOTAL_GB} GB"
echo "$ICON_TIME      Duration: $(format_duration $((END - START)))"
echo "$ICON_DONE      Status:   $ICON_SUCCESS DONE"
echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"

notify "Bandwidth report on $(hostname) — ${TOTAL_GB}GB transferred (${OLDEST} to ${NEWEST})" "Bandwidth Monitor" "normal"