#!/bin/bash
# -----------------------------------------------------------------------------------------------
# --------------------------------- Transcode Manager ------------------------------------------
# -----------------------------------------------------------------------------------------------
# Manages Emby transcode storage using filesystem symlink indirection.
# ffmpeg resolves the symlink ONCE at session start — existing sessions are never affected.
# Only new sessions care about where the symlink currently points.
#
# Three operating modes — set TRANSCODE_MANAGER_MODE in Master.conf:
#   smart   — auto-flips between ramdisk and SSD based on usage thresholds (default)
#   ramdisk — always uses ramdisk, never flips to SSD regardless of usage
#   ssd     — always uses SSD, never uses ramdisk
#
# Safety checks on every run regardless of mode:
#   Ramdisk disappeared → auto-flip to SSD, notify warning
#   SSD path missing    → disable SSD fallback, notify warning
#   Symlink broken      → auto-recreate, notify
#   Symlink missing     → auto-recreate, notify
#   Permissions drift   → fix silently
#   Emby not running    → skip threshold checks, verify symlink only
#
# All configuration in Master.conf under Transcode Manager section.
# Supports --dry-run and --status.
# -----------------------------------------------------------------------------------------------

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

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

parse_args "$@"

# -----------------------------------------------------------------------------------------------
# ━━━ $ICON_GEAR Setup ━━━
# -----------------------------------------------------------------------------------------------
echo ""
echo "━━━ $ICON_GEAR Setup ━━━"

if [[ "$EUID" -ne 0 ]]; then
    error "Must be run as root"
    exit 1
fi

success "Running as root"

case "$TRANSCODE_MANAGER_MODE" in
    smart|ramdisk|ssd) info "$ICON_GEAR Mode: $TRANSCODE_MANAGER_MODE" ;;
    *)
        warn "Unknown TRANSCODE_MANAGER_MODE: $TRANSCODE_MANAGER_MODE — defaulting to smart"
        TRANSCODE_MANAGER_MODE="smart"
        ;;
esac

[[ "$DRY_RUN" == true ]] && warn "DRY RUN — no changes will be made"

# -----------------------------------------------------------------------------------------------
# ━━━ $ICON_SUMMARY Status ━━━
# -----------------------------------------------------------------------------------------------
if [[ "$SHOW_STATUS" == true ]]; then
    echo ""
    echo "━━━━━ $ICON_SUMMARY STATUS ━━━━━"
    echo "$ICON_GEAR  Mode:         $TRANSCODE_MANAGER_MODE"
    echo "$ICON_RAM   Ramdisk:      $RAMDISK_PATH ($RAMDISK_SIZE)"
    echo "$ICON_LINK  Symlink:      $TRANSCODE_LINK"
    echo "$ICON_DISK  SSD:          $TRANSCODE_SSD"
    echo "$ICON_RAM   Warn at:      ${RAMDISK_WARN_GB}GB"
    echo "$ICON_RAM   Low at:       ${RAMDISK_LOW_GB}GB"
    echo "$ICON_DISK  SSD min free: ${RAMDISK_SSD_MIN_GB}GB"
    echo "$ICON_RAM   Flip warn:    $TRANSCODE_FLIP_WARN per hour"
    echo "$ICON_GEAR  Check Emby:   $TRANSCODE_CHECK_EMBY ($TRANSCODE_EMBY_CONTAINER)"
    echo "$ICON_GEAR  Dry Run:      $DRY_RUN"
    CURRENT_TARGET=$(readlink "$TRANSCODE_LINK" 2>/dev/null || echo "missing")
    echo "$ICON_LINK  Symlink now:  $TRANSCODE_LINK → $CURRENT_TARGET"
    if mountpoint -q "$RAMDISK_PATH" 2>/dev/null; then
        USED_KB=$(df "$RAMDISK_PATH" --output=used | tail -1 | tr -d ' ')
        USED_GB=$(awk "BEGIN {printf \"%.2f\", $USED_KB / 1048576}")
        echo "$ICON_RAM   Ramdisk now:  ${USED_GB}GB used"
    else
        echo "$ICON_RAM   Ramdisk:      NOT MOUNTED"
    fi
    echo "━━━━━━━━━━━━━━━━━━━━━━━"
    exit 0
fi

# -----------------------------------------------------------------------------------------------
# HELPERS
# -----------------------------------------------------------------------------------------------

flip_symlink() {
    local target="$1" reason="$2"
    if [[ "$DRY_RUN" == true ]]; then
        warn "DRY RUN — would flip symlink to: $target ($reason)"
        return 0
    fi
    ln -sfn "$target" "$TRANSCODE_LINK"
    success "$ICON_LINK Symlink flipped to: $target ($reason)"
}

fix_permissions() {
    local path="$1"
    [[ ! -d "$path" ]] && return
    chown -R "$TRANSCODE_OWNER" "$path" 2>/dev/null
    chmod -R "$TRANSCODE_CHMOD" "$path" 2>/dev/null
    log "Permissions fixed on $path"
}

get_ramdisk_used_gb() {
    local used_kb
    used_kb=$(df "$RAMDISK_PATH" --output=used 2>/dev/null | tail -1 | tr -d ' ')
    awk "BEGIN {printf \"%.2f\", ${used_kb:-0} / 1048576}"
}

get_ramdisk_avail_gb() {
    local avail_kb
    avail_kb=$(df "$RAMDISK_PATH" --output=avail 2>/dev/null | tail -1 | tr -d ' ')
    awk "BEGIN {printf \"%.2f\", ${avail_kb:-0} / 1048576}"
}

get_ssd_free_gb() {
    local free_kb
    free_kb=$(df "$TRANSCODE_SSD" --output=avail 2>/dev/null | tail -1 | tr -d ' ')
    awk "BEGIN {printf \"%.2f\", ${free_kb:-0} / 1048576}"
}

get_flip_count() {
    local state_file="/tmp/transcode_flip_state.db"
    local current_hour
    current_hour=$(date '+%Y-%m-%d-%H')
    if [[ ! -f "$state_file" ]]; then echo "0"; return; fi
    local stored_hour stored_count
    stored_hour=$(awk -F'|' 'NR==1{print $1}' "$state_file" 2>/dev/null)
    stored_count=$(awk -F'|' 'NR==1{print $2}' "$state_file" 2>/dev/null)
    [[ "$stored_hour" == "$current_hour" ]] && echo "${stored_count:-0}" || echo "0"
}

increment_flip_count() {
    local state_file="/tmp/transcode_flip_state.db"
    local current_hour
    current_hour=$(date '+%Y-%m-%d-%H')
    local current_count
    current_count=$(get_flip_count)
    current_count=$((current_count + 1))
    echo "${current_hour}|${current_count}" > "$state_file"
    echo "$current_count"
}

# -----------------------------------------------------------------------------------------------
# ━━━ $ICON_RAM Transcode Manager ━━━
# -----------------------------------------------------------------------------------------------
echo ""
echo "━━━ $ICON_RAM Transcode Manager — $(date '+%Y-%m-%d %H:%M:%S') ━━━"
echo "$ICON_GEAR Mode: $TRANSCODE_MANAGER_MODE"
echo ""

START=$(date +%s)
RAMDISK_HEALTHY=true
SSD_HEALTHY=true
EMBY_RUNNING=true

# -----------------------------------------------------------------------------------------------
# CHECK 1 — Emby running
# -----------------------------------------------------------------------------------------------
if [[ "$TRANSCODE_CHECK_EMBY" == true ]]; then
    info "$ICON_CONTAINERS Checking $TRANSCODE_EMBY_CONTAINER..."
    if ! docker inspect "$TRANSCODE_EMBY_CONTAINER" \
        --format '{{.State.Running}}' 2>/dev/null | grep -q "true"; then
        warn "$TRANSCODE_EMBY_CONTAINER is not running — skipping threshold checks"
        EMBY_RUNNING=false
    else
        success "$TRANSCODE_EMBY_CONTAINER is running"
    fi
fi

# -----------------------------------------------------------------------------------------------
# CHECK 2 — Symlink integrity
# -----------------------------------------------------------------------------------------------
echo ""
info "$ICON_LINK Checking symlink integrity..."

CURRENT_TARGET=$(readlink "$TRANSCODE_LINK" 2>/dev/null)

if [[ -z "$CURRENT_TARGET" ]]; then
    warn "$ICON_LINK Symlink missing — recreating pointing to ramdisk"
    if [[ "$DRY_RUN" == false ]]; then
        ln -sfn "$RAMDISK_PATH" "$TRANSCODE_LINK"
        CURRENT_TARGET="$RAMDISK_PATH"
        notify "Transcode symlink was missing on $(hostname) — recreated" "Transcode Manager" "warning"
    fi
elif [[ ! -e "$CURRENT_TARGET" ]]; then
    warn "$ICON_LINK Symlink target missing: $CURRENT_TARGET — resetting to ramdisk"
    if [[ "$DRY_RUN" == false ]]; then
        ln -sfn "$RAMDISK_PATH" "$TRANSCODE_LINK"
        CURRENT_TARGET="$RAMDISK_PATH"
        notify "Transcode symlink target was missing on $(hostname) — reset to ramdisk" "Transcode Manager" "warning"
    fi
else
    success "$ICON_LINK Symlink valid: $TRANSCODE_LINK → $CURRENT_TARGET"
fi

# -----------------------------------------------------------------------------------------------
# CHECK 3 — Ramdisk health
# -----------------------------------------------------------------------------------------------
echo ""
info "$ICON_RAM Checking ramdisk..."

if ! mountpoint -q "$RAMDISK_PATH" 2>/dev/null; then
    error "$ICON_RAM Ramdisk not mounted at $RAMDISK_PATH"
    RAMDISK_HEALTHY=false
    if [[ "$DRY_RUN" == false ]]; then
        warn "Flipping symlink to SSD — ramdisk unavailable"
        flip_symlink "$TRANSCODE_SSD" "ramdisk disappeared"
        CURRENT_TARGET="$TRANSCODE_SSD"
        notify "Ramdisk disappeared on $(hostname) — transcodes falling back to SSD. Run ramdisk_setup.sh to restore." "Transcode Manager" "warning"
    fi
else
    RAMDISK_SIZE_ACTUAL=$(df "$RAMDISK_PATH" --output=size -h | tail -1 | tr -d ' ')
    success "$ICON_RAM Ramdisk mounted — size: $RAMDISK_SIZE_ACTUAL"
    fix_permissions "$RAMDISK_PATH"
fi

# -----------------------------------------------------------------------------------------------
# CHECK 4 — SSD health
# -----------------------------------------------------------------------------------------------
echo ""
info "$ICON_DISK Checking SSD fallback..."

if [[ ! -d "$TRANSCODE_SSD" ]]; then
    warn "$ICON_DISK SSD fallback path missing: $TRANSCODE_SSD"
    SSD_HEALTHY=false
    if [[ "$TRANSCODE_MANAGER_MODE" == "ssd" ]]; then
        error "Mode is 'ssd' but SSD path is missing — cannot continue"
        notify "Transcode SSD path missing on $(hostname) — mode is 'ssd', manual intervention needed" "Transcode Manager" "warning"
        exit 1
    else
        warn "SSD fallback disabled — will stay on ramdisk"
    fi
else
    SSD_FREE_GB=$(get_ssd_free_gb)
    success "$ICON_DISK SSD available — ${SSD_FREE_GB}GB free"
    fix_permissions "$TRANSCODE_SSD"
fi

# -----------------------------------------------------------------------------------------------
# USAGE STATS
# -----------------------------------------------------------------------------------------------
echo ""
RAMDISK_USED_GB="0.00"
RAMDISK_AVAIL_GB="0.00"

if [[ "$RAMDISK_HEALTHY" == true ]]; then
    RAMDISK_USED_GB=$(get_ramdisk_used_gb)
    RAMDISK_AVAIL_GB=$(get_ramdisk_avail_gb)
    RAMDISK_FILES=$(find "$RAMDISK_PATH" -type f 2>/dev/null | wc -l)
    RAMDISK_SIZE_H=$(du -sh "$RAMDISK_PATH" 2>/dev/null | cut -f1)
fi

SSD_FILES=$(find "$TRANSCODE_SSD" -type f 2>/dev/null | wc -l)
SSD_SIZE_H=$(du -sh "$TRANSCODE_SSD" 2>/dev/null | cut -f1)

info "$ICON_RAM Ramdisk usage: ${RAMDISK_USED_GB}GB used / ${RAMDISK_AVAIL_GB}GB available"
info "$ICON_RAM Ramdisk files: ${RAMDISK_FILES:-0} ($RAMDISK_SIZE_H)"
info "$ICON_DISK SSD files: $SSD_FILES ($SSD_SIZE_H)"

FLIP_COUNT=$(get_flip_count)

# -----------------------------------------------------------------------------------------------
# MODE LOGIC
# -----------------------------------------------------------------------------------------------
echo ""

case "$TRANSCODE_MANAGER_MODE" in

    ramdisk)
        info "$ICON_RAM Mode: RAMDISK — forcing symlink to ramdisk"
        if [[ "$RAMDISK_HEALTHY" == false ]]; then
            error "Ramdisk mode selected but ramdisk is not available"
            notify "Transcode ramdisk mode failed on $(hostname) — ramdisk not mounted" "Transcode Manager" "warning"
        else
            if [[ "$CURRENT_TARGET" != "$RAMDISK_PATH" ]]; then
                flip_symlink "$RAMDISK_PATH" "ramdisk mode"
                increment_flip_count > /dev/null
            else
                log "Symlink already points to ramdisk — no change"
            fi
            if (( $(awk "BEGIN {print ($RAMDISK_USED_GB >= $RAMDISK_WARN_GB) ? 1 : 0}") )); then
                warn "$ICON_RAM Ramdisk usage ${RAMDISK_USED_GB}GB above threshold ${RAMDISK_WARN_GB}GB — consider switching to smart mode"
                notify "Ramdisk usage high on $(hostname) — ${RAMDISK_USED_GB}GB used in ramdisk-only mode" "Transcode Manager" "warning"
            fi
        fi
        ;;

    ssd)
        info "$ICON_DISK Mode: SSD — forcing symlink to SSD"
        if [[ "$SSD_HEALTHY" == false ]]; then
            error "SSD mode selected but SSD path is not available"
        else
            if [[ "$CURRENT_TARGET" != "$TRANSCODE_SSD" ]]; then
                flip_symlink "$TRANSCODE_SSD" "ssd mode"
                increment_flip_count > /dev/null
            else
                log "Symlink already points to SSD — no change"
            fi
        fi
        ;;

    smart)
        info "$ICON_GEAR Mode: SMART — auto threshold management"

        if [[ "$EMBY_RUNNING" == false ]]; then
            info "Emby not running — skipping threshold checks"

        elif [[ "$RAMDISK_HEALTHY" == false ]]; then
            info "Ramdisk unavailable — staying on SSD until ramdisk recovers"

        elif [[ "$CURRENT_TARGET" == "$RAMDISK_PATH" ]]; then
            # On ramdisk — check if we need to flip to SSD
            if (( $(awk "BEGIN {print ($RAMDISK_USED_GB >= $RAMDISK_WARN_GB) ? 1 : 0}") )); then
                if [[ "$SSD_HEALTHY" == false ]]; then
                    error "Ramdisk above threshold but SSD unavailable — cannot flip"
                    notify "Transcode ramdisk full on $(hostname) and SSD unavailable — intervention needed" "Transcode Manager" "warning"
                else
                    SSD_FREE_GB=$(get_ssd_free_gb)
                    if (( $(awk "BEGIN {print ($SSD_FREE_GB < $RAMDISK_SSD_MIN_GB) ? 1 : 0}") )); then
                        warn "$ICON_DISK SSD only ${SSD_FREE_GB}GB free — below ${RAMDISK_SSD_MIN_GB}GB minimum, not flipping"
                    else
                        warn "$ICON_RAM Ramdisk ${RAMDISK_USED_GB}GB — above ${RAMDISK_WARN_GB}GB, flipping to SSD"
                        flip_symlink "$TRANSCODE_SSD" "threshold exceeded"
                        CURRENT_TARGET="$TRANSCODE_SSD"
                        NEW_COUNT=$(increment_flip_count)
                        FLIP_COUNT=$NEW_COUNT
                        if [[ "$NEW_COUNT" -ge "$TRANSCODE_FLIP_WARN" ]]; then
                            notify "Transcode flipped to SSD on $(hostname) — ${NEW_COUNT} flips this hour. Consider increasing RAMDISK_SIZE." "Transcode Manager" "warning"
                        fi
                    fi
                fi
            else
                log "Symlink already points to ramdisk — no change"
            fi

        elif [[ "$CURRENT_TARGET" == "$TRANSCODE_SSD" ]]; then
            # On SSD — check if we can flip back to ramdisk
            if (( $(awk "BEGIN {print ($RAMDISK_USED_GB <= $RAMDISK_LOW_GB) ? 1 : 0}") )); then
                info "$ICON_RAM Ramdisk ${RAMDISK_USED_GB}GB — below ${RAMDISK_LOW_GB}GB, flipping back to ramdisk"
                flip_symlink "$RAMDISK_PATH" "usage recovered"
                CURRENT_TARGET="$RAMDISK_PATH"
                NEW_COUNT=$(increment_flip_count)
                FLIP_COUNT=$NEW_COUNT
            else
                log "On SSD — ramdisk ${RAMDISK_USED_GB}GB still above low threshold ${RAMDISK_LOW_GB}GB"
            fi
        fi
        ;;
esac

END=$(date +%s)
CURRENT_TARGET=$(readlink "$TRANSCODE_LINK" 2>/dev/null || echo "unknown")

# -----------------------------------------------------------------------------------------------
# ━━━ $ICON_SUMMARY Summary ━━━
# -----------------------------------------------------------------------------------------------
echo ""
echo "━━━━━ $ICON_SUMMARY TRANSCODE MANAGER SUMMARY ━━━━━"
echo "$ICON_GEAR  Mode:      $TRANSCODE_MANAGER_MODE"
echo "$ICON_RAM   Ramdisk:   ${RAMDISK_USED_GB}GB used / ${RAMDISK_AVAIL_GB}GB available"
echo "$ICON_LINK  Symlink:   $TRANSCODE_LINK → $CURRENT_TARGET"
echo "$ICON_LINK  Flips:     $FLIP_COUNT this hour (warn at $TRANSCODE_FLIP_WARN)"
echo "$ICON_TIME  Duration:  $(format_duration $((END - START)))"
echo "$ICON_DONE  Status:    $ICON_SUCCESS DONE"
echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"