#!/bin/bash
# ==============================================================================================
# ================================= Ramdisk Setup ==============================================
# ==============================================================================================
# Creates a tmpfs ramdisk for Emby transcodes and points the transcode symlink at it.
# Run once at array start via User Scripts plugin — scheduled as "At Startup of Array".
# If ramdisk is already mounted reports status and exits cleanly without remounting.
#
# ── WHAT IT CREATES ───────────────────────────────────────────────────────────────────────────
#   RAMDISK_PATH      — tmpfs mount point (in-memory transcode location)
#                       Size: HOST*_RAMDISK_SIZE (e.g. 8G) — must fit in available RAM
#   TRANSCODE_SSD     — SSD fallback directory (created if missing)
#                       transcode_manager.sh flips symlink here if ramdisk fills up
#   TRANSCODE_LINK    — symlink pointing at RAMDISK_PATH by default
#   transcoding-temp/ — pre-created inside ramdisk so Emby always finds it there
#                       Without this Emby creates it at its own first-writable location
#                       which may be SSD even when symlink points at ramdisk
#
# ── TRANSCODE_LINK SYMLINK ────────────────────────────────────────────────────────────────────
# Emby's transcode path is set to TRANSCODE_LINK in Emby config.
# transcode_manager.sh flips the symlink between RAMDISK_PATH and TRANSCODE_SSD at runtime
# based on ramdisk usage — Emby sessions automatically follow without restart.
# This script always sets the link to RAMDISK_PATH at array start (clean state).
#
# ── STATE FILE ────────────────────────────────────────────────────────────────────────────────
# Initialises /tmp/transcode_state.db with current target and flip tracking counters.
# /tmp resets on reboot — correct, transcode state is ephemeral.
#
# ── HOST AWARENESS ────────────────────────────────────────────────────────────────────────────
# detect_hosts() sets MY_ID and aliases HOST*_RAMDISK_SIZE → RAMDISK_SIZE.
# HOST*_RAMDISK_SIZE, HOST*_RAMDISK_WARN_GB, HOST*_RAMDISK_LOW_GB must all be
# configured per host — different servers have different amounts of RAM available.
#
# ── SAFEGUARDS ────────────────────────────────────────────────────────────────────────────────
#   Root check           — mount and symlink require root
#   acquire_lock         — prevents duplicate runs at array start
#   detect_hosts()       — correct RAMDISK_SIZE per host
#   Already mounted      — exits cleanly without remounting (idempotent)
#   validate_unraid_cmd  — notify validated before use
#   Silent on success    — startup script runs every boot — no noise when healthy
#
# ── CONFIGURATION (master_host*.conf) ─────────────────────────────────────────────────────────
#   HOST*_RAMDISK_SIZE     — tmpfs size (e.g. 8G) — must change together with WARN_GB/LOW_GB
#   HOST*_RAMDISK_WARN_GB  — warn threshold in GB
#   HOST*_RAMDISK_LOW_GB   — flip to SSD threshold in GB
#   HOST*_TRANSCODE_SSD    — SSD fallback path
#   HOST*_TRANSCODE_SERVERS — which servers run transcoding
#   Aliased by detect_hosts()
#
# ── CONFIGURATION (master.conf) ───────────────────────────────────────────────────────────────
#   TRANSCODE_LINK    — symlink path Emby uses as transcode directory
#   TRANSCODE_CHMOD   — permissions applied to ramdisk and fallback
#   TRANSCODE_OWNER   — owner applied (default nobody:users)
#
# ── USAGE ─────────────────────────────────────────────────────────────────────────────────────
#   ramdisk_setup.sh              — normal setup (runs at array start)
#   ramdisk_setup.sh --dry-run    — preview without making changes
#   ramdisk_setup.sh --status     — show current ramdisk and symlink state
#   ramdisk_setup.sh --log        — verbose output
# ==============================================================================================

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

source "$SCRIPT_DIR/../load_config.sh"

parse_args "$@"

# ==============================================================================================
# ━━━ Setup ━━━
# ==============================================================================================
if [[ "$EUID" -ne 0 ]]; then
    error "Must be run as root — mount and symlink require root"
    exit 1
fi

validate_unraid_cmd \
    "/usr/local/emhttp/plugins/dynamix/scripts/notify" \
    "" "" \
    "unRAID notify script" || warn "unRAID notify script not found — native notifications disabled"

acquire_lock

# detect_hosts() sets MY_ID and aliases RAMDISK_SIZE, TRANSCODE_SSD etc.
detect_hosts

log "Identity:  $MY_ID ($LOCAL_SERVER_NAME)"
log "Ramdisk:   $RAMDISK_PATH ($RAMDISK_SIZE)"
log "Fallback:  $TRANSCODE_SSD"
log "Symlink:   $TRANSCODE_LINK"

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

# ==============================================================================================
# ━━━ Status ━━━
# ==============================================================================================
if [[ "$SHOW_STATUS" == true ]]; then
    echo ""
    echo "━━━━━ $ICON_SUMMARY STATUS ━━━━━"
    echo "$ICON_HOST   Identity:      $MY_ID ($LOCAL_SERVER_NAME)"
    echo "$ICON_RAM    Ramdisk path:  $RAMDISK_PATH"
    echo "$ICON_RAM    Ramdisk size:  $RAMDISK_SIZE"
    echo "$ICON_RAM    Warn at:       ${RAMDISK_WARN_GB}GB"
    echo "$ICON_RAM    Flip at:       ${RAMDISK_LOW_GB}GB"
    echo "$ICON_DISK   SSD fallback:  $TRANSCODE_SSD"
    echo "$ICON_LINK   Symlink:       $TRANSCODE_LINK"
    echo "$ICON_GEAR   Owner:         $TRANSCODE_OWNER"
    echo "$ICON_GEAR   Mode:          $TRANSCODE_CHMOD"
    echo ""

    if mountpoint -q "$RAMDISK_PATH" 2>/dev/null; then
        USAGE=$(df -BG "$RAMDISK_PATH" | awk 'NR==2 {print $3}')
        AVAIL=$(df -BG "$RAMDISK_PATH" | awk 'NR==2 {print $4}')
        echo "  $ICON_RAM  Ramdisk: mounted — $USAGE used / $AVAIL available ✅"
    else
        echo "  $ICON_RAM  Ramdisk: NOT mounted"
    fi

    if [[ -L "$TRANSCODE_LINK" ]]; then
        TARGET=$(readlink "$TRANSCODE_LINK")
        echo "  $ICON_LINK Symlink: $TRANSCODE_LINK → $TARGET"
    else
        echo "  $ICON_LINK Symlink: not set"
    fi

    echo "━━━━━━━━━━━━━━━━━━━━━━━"
    exit 0
fi

# ==============================================================================================
# ━━━ Ramdisk ━━━
# ==============================================================================================
echo ""
echo "━━━ $ICON_RAM Ramdisk — $MY_ID ━━━"
echo "$ICON_RAM  Path: $RAMDISK_PATH"
echo "$ICON_RAM  Size: $RAMDISK_SIZE"
echo ""

START=$(date +%s)
SETUP_SUCCESS=true

if mountpoint -q "$RAMDISK_PATH" 2>/dev/null; then
    USAGE=$(df -BG "$RAMDISK_PATH" | awk 'NR==2 {print $3}')
    AVAIL=$(df -BG "$RAMDISK_PATH" | awk 'NR==2 {print $4}')
    log "Ramdisk already mounted — $USAGE used / $AVAIL available"
    log "Skipping mount — verifying symlink and permissions"
else
    if [[ "$DRY_RUN" == true ]]; then
        warn "DRY RUN — would create $RAMDISK_PATH"
        warn "DRY RUN — would mount tmpfs ${RAMDISK_SIZE} at $RAMDISK_PATH"
    else
        log "Creating ramdisk mount point: $RAMDISK_PATH"
        mkdir -p "$RAMDISK_PATH" || {
            error "Failed to create $RAMDISK_PATH"
            notify "Ramdisk setup failed on $(hostname) ($MY_ID) — could not create mount point" \
                "Ramdisk Setup" "warning"
            exit 1
        }

        log "Mounting tmpfs ${RAMDISK_SIZE} at $RAMDISK_PATH..."
        if mount -t tmpfs -o size="$RAMDISK_SIZE" tmpfs "$RAMDISK_PATH"; then
            warn "Ramdisk mounted — ${RAMDISK_SIZE} at $RAMDISK_PATH ✅"
        else
            error "Failed to mount ramdisk at $RAMDISK_PATH"
            notify "Ramdisk setup failed on $(hostname) ($MY_ID) — mount failed" \
                "Ramdisk Setup" "warning"
            exit 1
        fi
    fi
fi

# ==============================================================================================
# ━━━ SSD Fallback ━━━
# ==============================================================================================
echo ""
echo "━━━ $ICON_DISK SSD Fallback ━━━"

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — would create SSD fallback: $TRANSCODE_SSD"
else
    if [[ -d "$TRANSCODE_SSD" ]]; then
        log "SSD fallback already exists: $TRANSCODE_SSD"
    else
        log "Creating SSD fallback directory: $TRANSCODE_SSD"
        if mkdir -p "$TRANSCODE_SSD"; then
            log "SSD fallback created: $TRANSCODE_SSD ✅"
        else
            error "Failed to create SSD fallback: $TRANSCODE_SSD"
            SETUP_SUCCESS=false
        fi
    fi
fi

# ==============================================================================================
# ━━━ Symlink ━━━
# ==============================================================================================
echo ""
echo "━━━ $ICON_LINK Symlink ━━━"

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — would set $TRANSCODE_LINK → $RAMDISK_PATH"
else
    if [[ -L "$TRANSCODE_LINK" ]]; then
        CURRENT_TARGET=$(readlink "$TRANSCODE_LINK")
        if [[ "$CURRENT_TARGET" == "$RAMDISK_PATH" ]]; then
            log "Symlink already points to ramdisk — no change needed ✅"
        else
            log "Updating symlink: $CURRENT_TARGET → $RAMDISK_PATH"
            ln -sfn "$RAMDISK_PATH" "$TRANSCODE_LINK" || {
                error "Failed to update symlink"
                SETUP_SUCCESS=false
            }
        fi
    elif [[ -e "$TRANSCODE_LINK" ]]; then
        warn "$TRANSCODE_LINK exists but is not a symlink — removing and replacing"
        rm -rf "$TRANSCODE_LINK"
        ln -sfn "$RAMDISK_PATH" "$TRANSCODE_LINK" || {
            error "Failed to create symlink"
            SETUP_SUCCESS=false
        }
    else
        log "Creating symlink: $TRANSCODE_LINK → $RAMDISK_PATH"
        mkdir -p "$(dirname "$TRANSCODE_LINK")"
        ln -sfn "$RAMDISK_PATH" "$TRANSCODE_LINK" || {
            error "Failed to create symlink"
            SETUP_SUCCESS=false
        }
    fi

    [[ "$SETUP_SUCCESS" == true ]] && log "Symlink: $TRANSCODE_LINK → $RAMDISK_PATH ✅"
fi

# ==============================================================================================
# ━━━ Transcoding-temp Directory ━━━
# ==============================================================================================
# Pre-created inside ramdisk so Emby always finds it there at session start.
# Without this Emby creates it at its own first-writable path — which may be
# SSD even when the symlink points at the ramdisk — locking all sessions onto SSD.
echo ""
echo "━━━ $ICON_GEAR Transcoding Temp Directory ━━━"

TRANSCODE_TEMP_DIR="${RAMDISK_PATH}/transcoding-temp"

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — would create $TRANSCODE_TEMP_DIR"
else
    if [[ -d "$TRANSCODE_TEMP_DIR" ]]; then
        log "transcoding-temp already exists on ramdisk"
    else
        if mkdir -p "$TRANSCODE_TEMP_DIR"; then
            log "Created transcoding-temp on ramdisk ✅"
        else
            error "Failed to create transcoding-temp on ramdisk"
            SETUP_SUCCESS=false
        fi
    fi

    if [[ -d "$TRANSCODE_TEMP_DIR" ]]; then
        chmod "$TRANSCODE_CHMOD" "$TRANSCODE_TEMP_DIR"
        chown "$TRANSCODE_OWNER" "$TRANSCODE_TEMP_DIR"
        log "Permissions set on transcoding-temp ($TRANSCODE_CHMOD $TRANSCODE_OWNER)"
    fi
fi

# ==============================================================================================
# ━━━ Permissions ━━━
# ==============================================================================================
echo ""
echo "━━━ $ICON_GEAR Permissions ━━━"

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — would apply $TRANSCODE_CHMOD $TRANSCODE_OWNER to $RAMDISK_PATH and $TRANSCODE_SSD"
else
    for path in "$RAMDISK_PATH" "$TRANSCODE_SSD"; do
        if [[ -d "$path" ]]; then
            chmod "$TRANSCODE_CHMOD" "$path"
            chown "$TRANSCODE_OWNER" "$path"
            log "Permissions set: $path ($TRANSCODE_CHMOD $TRANSCODE_OWNER)"
        fi
    done
fi

# ==============================================================================================
# ━━━ Initialise State File ━━━
# ==============================================================================================
if [[ "$DRY_RUN" == false ]]; then
    STATE_FILE="/tmp/transcode_state.db"
    NOW=$(date +%s)
    cat > "$STATE_FILE" <<EOF
current_target=$RAMDISK_PATH
last_flip_time=$NOW
flip_count_hour=0
flip_hour_start=$NOW
EOF
    log "State file initialised: $STATE_FILE"
fi

END=$(date +%s)

# ==============================================================================================
# ━━━ Summary ━━━
# ==============================================================================================
echo ""
echo "━━━━━ $ICON_SUMMARY RAMDISK SETUP SUMMARY ━━━━━"
echo "$ICON_HOST  Identity: $MY_ID ($LOCAL_SERVER_NAME)"
echo "$ICON_RAM   Ramdisk:  $RAMDISK_PATH ($RAMDISK_SIZE)"
echo "$ICON_DISK  Fallback: $TRANSCODE_SSD"
echo "$ICON_LINK  Symlink:  $TRANSCODE_LINK"
echo "$ICON_TIME  Duration: $(format_duration $(( END - START )))"
echo ""

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — no changes made"
elif [[ "$SETUP_SUCCESS" == true ]]; then
    log "$ICON_DONE Status: done ✅"
else
    echo "$ICON_ERROR Status: SETUP HAD ERRORS"
    notify "Ramdisk setup errors on $(hostname) ($MY_ID) — check output" \
        "Ramdisk Setup" "warning"
    exit 1
fi
echo "━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━"