#!/bin/bash
# ==============================================================================================
# ================================= Play State Sync ============================================
# ==============================================================================================
#
# PURPOSE
# ─────────────────────────────────────────────────────────────────────────────
# Syncs watched/played state and resume positions across all configured Emby
# and Jellyfin servers. Newest timestamp wins — no data is ever lost.
#
# Users are matched by name (case-insensitive). If a user exists on some servers
# but not others, those servers are skipped for that user — no errors, no partial
# syncs from unrelated accounts.
#
# Items are matched by external provider IDs:
#   Movies   → IMDb ID, then TMDB ID
#   Episodes → TVDB ID + season + episode number
#   Audio    → MusicBrainz Track ID
#
# ==============================================================================================
# SYNC LOGIC
# ==============================================================================================
#
# For each matched item across ≥2 servers:
#   1. Compare LastPlayedDate across all servers that have a play record.
#   2. The server with the newest LastPlayedDate is authoritative.
#   3. Push that server's state (Played, PlayCount, LastPlayedDate,
#      PlaybackPositionTicks) to every other server.
#   4. Servers with no record for that item also receive the state.
#
# Resume positions (partial plays, not marked Played):
#   Synced by comparing PlaybackPositionTicks when LastPlayedDate is absent.
#   The higher tick count wins.
#
# ==============================================================================================
# CONFIGURATION (host*.conf, aliased by detect_hosts)
# ==============================================================================================
#
#   HOST*_TRANSCODE_SERVERS  "Name|URL|APIKey|type" entries per host (emby/jellyfin)
#                            All hosts are discovered automatically — no extra config needed.
#                            Remote host URLs have localhost rewritten to their Tailscale IP.
#
# master.conf
#
#   PLAY_SYNC_ENABLED        Master toggle (default: true)
#   PLAY_SYNC_REMOTE         Sync across all hosts via Tailscale (default: true)
#                            false = local servers only (this host's Emby + Jellyfin)
#   PLAY_SYNC_DAYS           How many days back to check for played items (default: 90)
#                            Use 0 to sync all played items (slow on large libraries).
#   PLAY_SYNC_TYPES          Comma-separated item types to sync (default: Movie,Episode,Audio)
#
# ==============================================================================================
# RUNTIME MODES
# ==============================================================================================
#
# play_state_sync.sh
#     Sync all matched users across all configured servers.
#
# play_state_sync.sh --dry-run
#     Show what would be synced without writing any state.
#
# play_state_sync.sh --status
#     Show configured servers, reachability, and user counts.
#
# play_state_sync.sh --full
#     Ignore PLAY_SYNC_DAYS — sync all played items (may be slow).
#
# play_state_sync.sh --log
#     Verbose output — show each item comparison.
#
# ==============================================================================================

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$SCRIPT_DIR/../load_config.sh"

# ── Handle --full before parse_args ───────────────────────────────────────────
FULL_SYNC=false
_FILTERED=()
for _a in "$@"; do
    [[ "$_a" == "--full" ]] && FULL_SYNC=true || _FILTERED+=("$_a")
done
parse_args "${_FILTERED[@]}"

# ==============================================================================================
# ━━━ Setup ━━━
# ==============================================================================================
[[ "${PLAY_SYNC_ENABLED:-true}" != "true" ]] && echo "Play state sync disabled" && exit 0

SYNC_DAYS="${PLAY_SYNC_DAYS:-90}"
SYNC_TYPES="${PLAY_SYNC_TYPES:-Movie,Episode,Audio}"
[[ "$FULL_SYNC" == true ]] && SYNC_DAYS=0
log "$ICON_GEAR Config: days=${SYNC_DAYS} types=${SYNC_TYPES} remote=${PLAY_SYNC_REMOTE:-true}"

command -v jq >/dev/null 2>&1 || { error "jq is required but not installed"; exit 1; }

acquire_lock

# ── Build server list across ALL hosts ────────────────────────────────────────
# All HOST*_TRANSCODE_SERVERS arrays are loaded into env by load_config.sh.
# For remote hosts, localhost in the URL is rewritten to their Tailscale IP.
declare -a SRV_NAME SRV_URL SRV_KEY SRV_TYPE
_srv_count=0
_my_hostname=$(hostname -s)

_add_server() {
    local name="$1" url="$2" key="$3" type="$4"
    [[ -z "$url" || -z "$key" ]] && return
    [[ "$key" == "YOUR_API_KEY"* || "$key" == "placeholder"* ]] && return
    SRV_NAME[$_srv_count]="$name"
    SRV_URL[$_srv_count]="$url"
    SRV_KEY[$_srv_count]="$key"
    SRV_TYPE[$_srv_count]="$type"
    (( _srv_count++ ))
}

for _varname in $(compgen -v | grep -E '^HOST[0-9]+$' | sort); do
    _num="${_varname//[^0-9]/}"
    _host_hostname="${!_varname}"
    [[ -z "$_host_hostname" ]] && continue

    _is_me=false
    [[ "${_host_hostname,,}" == "${_my_hostname,,}" ]] && _is_me=true

    # Skip remote hosts when PLAY_SYNC_REMOTE=false
    if [[ "$_is_me" == false && "${PLAY_SYNC_REMOTE:-true}" != "true" ]]; then
        log "$_host_hostname — remote sync disabled (PLAY_SYNC_REMOTE=false), skipping"
        continue
    fi

    # Resolve Tailscale IP for remote hosts
    _ts_ip=""
    if [[ "$_is_me" == false ]]; then
        _ts_ip=$(resolve_tailscale_ip "$_host_hostname")
        if [[ -z "$_ts_ip" ]]; then
            log "$_host_hostname — Tailscale IP not found, skipping"
            continue
        fi
    fi

    # Load this host's TRANSCODE_SERVERS array
    _srv_arr_name="HOST${_num}_TRANSCODE_SERVERS"
    eval "_host_entries=(\"\${${_srv_arr_name}[@]}\")"
    [[ "${#_host_entries[@]}" -eq 0 ]] && continue

    for _entry in "${_host_entries[@]}"; do
        IFS='|' read -r _name _url _key _type <<< "$_entry"
        [[ "$_type" == "emby" || "$_type" == "jellyfin" ]] || continue
        # For remote hosts rewrite localhost/127.0.0.1 → Tailscale IP
        if [[ "$_is_me" == false ]]; then
            _url="${_url//localhost/$_ts_ip}"
            _url="${_url//127.0.0.1/$_ts_ip}"
        fi
        _add_server "${_name} (${_host_hostname})" "$_url" "$_key" "$_type"
    done
done

if [[ "$_srv_count" -lt 2 ]]; then
    error "Need at least 2 media servers configured — found $_srv_count"
    exit 1
fi

# ==============================================================================================
# ━━━ API Helpers ━━━
# ==============================================================================================
_api_get() {
    local url="$1" key="$2" endpoint="$3"
    curl -sf --max-time 30 \
        -H "X-Emby-Token: $key" \
        "${url%/}/${endpoint}" 2>/dev/null
}

_api_post() {
    local url="$1" key="$2" endpoint="$3" data="${4:-}"
    if [[ -n "$data" ]]; then
        curl -sf --max-time 30 -s -o /dev/null -w "%{http_code}" -X POST \
            -H "X-Emby-Token: $key" \
            -H "Content-Type: application/json" \
            -d "$data" \
            "${url%/}/${endpoint}" 2>/dev/null
    else
        curl -sf --max-time 30 -s -o /dev/null -w "%{http_code}" -X POST \
            -H "X-Emby-Token: $key" \
            "${url%/}/${endpoint}" 2>/dev/null
    fi
}

# ISO 8601 date → unix seconds (portable, no date -d on BusyBox)
_iso_to_epoch() {
    local dt="$1"
    [[ -z "$dt" || "$dt" == "null" ]] && echo 0 && return
    # Strip fractional seconds and Z, convert to seconds
    dt="${dt%.*}"       # remove .NNNNNNN
    dt="${dt%Z}"        # remove trailing Z
    dt="${dt/T/ }"      # T → space
    date -u -d "$dt UTC" +%s 2>/dev/null || echo 0
}

# Ticks → seconds (1 tick = 100ns, 10_000_000 ticks = 1s)
_ticks_to_sec() {
    echo $(( ${1:-0} / 10000000 ))
}

# ==============================================================================================
# ━━━ Status ━━━
# ==============================================================================================
if [[ "$SHOW_STATUS" == true ]]; then
    echo ""
    echo "━━━━━ $ICON_SUMMARY PLAY STATE SYNC STATUS ━━━━━"
    echo "$ICON_GEAR  Remote sync: ${PLAY_SYNC_REMOTE:-true}"
    echo "$ICON_GEAR  Sync days:   ${SYNC_DAYS:-all}"
    echo "$ICON_GEAR  Item types:  $SYNC_TYPES"
    echo ""
    for i in $(seq 0 $(( _srv_count - 1 ))); do
        echo "$ICON_HOST  [${SRV_TYPE[$i]}] ${SRV_NAME[$i]}  (${SRV_URL[$i]})"
        _users=$(_api_get "${SRV_URL[$i]}" "${SRV_KEY[$i]}" "Users" 2>/dev/null | jq -r '.[].Name' 2>/dev/null | wc -l)
        if [[ "$_users" -gt 0 ]]; then
            echo "    $ICON_DONE Reachable — $_users user(s)"
            _api_get "${SRV_URL[$i]}" "${SRV_KEY[$i]}" "Users" 2>/dev/null \
                | jq -r '.[].Name' 2>/dev/null | while read -r n; do echo "      · $n"; done
        else
            echo "    $ICON_ERROR Unreachable or no users"
        fi
    done
    echo "━━━━━━━━━━━━━━━━━━━━━━━"
    exit 0
fi

# ==============================================================================================
# ━━━ Main Sync ━━━
# ==============================================================================================
echo "━━━ $ICON_SYNC Play State Sync — $(date '+%Y-%m-%d %H:%M:%S') ━━━"
[[ "$DRY_RUN" == true ]]  && warn "DRY RUN — no state will be written"
[[ "$FULL_SYNC" == true ]] && log "Full sync mode — ignoring PLAY_SYNC_DAYS"

START=$(date +%s)
TOTAL_SYNCED=0
TOTAL_SKIPPED=0
TOTAL_ERRORS=0

# ── Step 1: Fetch users from each server ─────────────────────────────────────
declare -A SRV_USERS   # idx → JSON array string of users

log "Fetching users..."
for i in $(seq 0 $(( _srv_count - 1 ))); do
    _resp=$(_api_get "${SRV_URL[$i]}" "${SRV_KEY[$i]}" "Users")
    if [[ -z "$_resp" ]]; then
        warn "${SRV_NAME[$i]} — unreachable, skipping"
        SRV_USERS[$i]=""
        continue
    fi
    SRV_USERS[$i]="$_resp"
    _count=$(echo "$_resp" | jq 'length' 2>/dev/null || echo 0)
    log "${SRV_NAME[$i]} — $_count user(s)"
done

# ── Step 2: Build cross-server user map ──────────────────────────────────────
# lowercase_name → "server_idx:user_id server_idx:user_id ..."
declare -A USER_MAP

for i in $(seq 0 $(( _srv_count - 1 ))); do
    [[ -z "${SRV_USERS[$i]}" ]] && continue
    while IFS=$'\t' read -r uid uname; do
        [[ -z "$uid" || -z "$uname" ]] && continue
        lname="${uname,,}"
        if [[ -n "${USER_MAP[$lname]}" ]]; then
            USER_MAP[$lname]+=" ${i}:${uid}"
        else
            USER_MAP[$lname]="${i}:${uid}"
        fi
    done < <(echo "${SRV_USERS[$i]}" | jq -r '.[] | [.Id, .Name] | @tsv' 2>/dev/null)
done

# ── Step 3: Sync per matched user ────────────────────────────────────────────
_date_filter=""
if [[ "$SYNC_DAYS" -gt 0 ]]; then
    _cutoff=$(date -u -d "$SYNC_DAYS days ago" '+%Y-%m-%dT%H:%M:%SZ' 2>/dev/null || \
              date -u -v "-${SYNC_DAYS}d" '+%Y-%m-%dT%H:%M:%SZ' 2>/dev/null)
    [[ -n "$_cutoff" ]] && _date_filter="&MinDateLastSaved=$_cutoff"
fi

for lname in "${!USER_MAP[@]}"; do
    read -ra _pairs <<< "${USER_MAP[$lname]}"

    # Skip users only on one server
    [[ "${#_pairs[@]}" -lt 2 ]] && log "  $lname — only on 1 server, skipping" && continue

    echo ""
    echo "── User: $lname (${#_pairs[@]} server(s)) ──"

    # Build per-server user context
    declare -A U_IDX U_UID
    for _pair in "${_pairs[@]}"; do
        IFS=':' read -r _si _ui <<< "$_pair"
        U_IDX["$_si"]="$_si"
        U_UID["$_si"]="$_ui"
    done

    # ── Fetch played items from each server for this user ────────────────────
    # Key: provider_id_string → sorted list of (epoch, srv_idx, item_id, play_count, ticks, played)
    declare -A ITEM_MAP   # provider_key → JSON per-server data

    for _si in "${!U_IDX[@]}"; do
        _uid="${U_UID[$_si]}"
        _endpoint="Users/${_uid}/Items?Recursive=true&Fields=ProviderIds,UserData,Type,ParentIndexNumber,IndexNumber,SeriesName&IncludeItemTypes=${SYNC_TYPES}&Filters=IsPlayed${_date_filter}&Limit=5000"
        _resp=$(_api_get "${SRV_URL[$_si]}" "${SRV_KEY[$_si]}" "$_endpoint")
        if [[ -z "$_resp" ]]; then
            warn "  ${SRV_NAME[$_si]} — failed to fetch items for $lname"
            continue
        fi

        # Also fetch items with resume position (not yet marked played)
        _endpoint2="Users/${_uid}/Items?Recursive=true&Fields=ProviderIds,UserData,Type,ParentIndexNumber,IndexNumber,SeriesName&IncludeItemTypes=${SYNC_TYPES}&SortBy=DatePlayed&SortOrder=Descending&Filters=IsResumable${_date_filter}&Limit=500"
        _resp2=$(_api_get "${SRV_URL[$_si]}" "${SRV_KEY[$_si]}" "$_endpoint2")

        # Combine and deduplicate by Id
        if [[ -n "$_resp2" ]]; then
            _combined=$(printf '%s\n%s' "$_resp" "$_resp2" | jq -s \
                '[.[0].Items // [], .[1].Items // []] | add // [] | unique_by(.Id)' 2>/dev/null)
        else
            _combined=$(echo "$_resp" | jq '.Items // []' 2>/dev/null)
        fi

        _count=$(echo "$_combined" | jq 'length' 2>/dev/null || echo 0)
        log "  ${SRV_NAME[$_si]} — $_count item(s) with state for $lname"

        # Build item lookup by provider key
        while IFS=$'\t' read -r iid itype season ep imdb tmdb tvdb mbtrack played ticks lplayed pcount; do
            # Build canonical provider key
            _pkey=""
            case "$itype" in
                Movie)
                    [[ "$imdb" != "null" && -n "$imdb" ]] && _pkey="imdb:${imdb}"
                    [[ -z "$_pkey" && "$tmdb" != "null" && -n "$tmdb" ]] && _pkey="tmdb:movie:${tmdb}"
                    ;;
                Episode)
                    [[ "$tvdb" != "null" && -n "$tvdb" && "$season" != "null" && "$ep" != "null" ]] && \
                        _pkey="tvdb:ep:${tvdb}:s${season}e${ep}"
                    ;;
                Audio)
                    [[ "$mbtrack" != "null" && -n "$mbtrack" ]] && _pkey="mb:track:${mbtrack}"
                    ;;
            esac
            [[ -z "$_pkey" ]] && continue

            _epoch=$(_iso_to_epoch "$lplayed")
            _entry="${_si}|${iid}|${played}|${pcount}|${ticks}|${_epoch}|${lplayed}"

            if [[ -n "${ITEM_MAP[$_pkey]}" ]]; then
                ITEM_MAP[$_pkey]+=$'\n'"$_entry"
            else
                ITEM_MAP[$_pkey]="$_entry"
            fi

        done < <(echo "$_combined" | jq -r '.[] | [
            .Id,
            .Type,
            (.ParentIndexNumber // "null" | tostring),
            (.IndexNumber // "null" | tostring),
            (.ProviderIds.Imdb // "null"),
            (.ProviderIds.Tmdb // "null"),
            (.ProviderIds.Tvdb // "null"),
            (.ProviderIds.MusicBrainzTrackId // "null"),
            (.UserData.Played // false | tostring),
            (.UserData.PlaybackPositionTicks // 0 | tostring),
            (.UserData.LastPlayedDate // "null"),
            (.UserData.PlayCount // 0 | tostring)
        ] | @tsv' 2>/dev/null)
    done

    # ── Compare and sync ─────────────────────────────────────────────────────
    for _pkey in "${!ITEM_MAP[@]}"; do
        # Collect all server entries for this item
        declare -A E_EPOCH E_PLAYED E_PCOUNT E_TICKS E_IID E_LPLAYED E_SIDX
        _has_entries=false

        while IFS='|' read -r _si _iid _played _pcount _ticks _epoch _lplayed; do
            [[ -z "$_si" ]] && continue
            E_SIDX[$_si]="$_si"
            E_IID[$_si]="$_iid"
            E_PLAYED[$_si]="$_played"
            E_PCOUNT[$_si]="$_pcount"
            E_TICKS[$_si]="$_ticks"
            E_EPOCH[$_si]="$_epoch"
            E_LPLAYED[$_si]="$_lplayed"
            _has_entries=true
        done <<< "${ITEM_MAP[$_pkey]}"

        [[ "$_has_entries" == false ]] && continue

        # Find the authoritative server: newest LastPlayedDate epoch
        # Tie-break: higher PlayCount, then higher Ticks
        _auth_si=""
        _auth_epoch=0
        _auth_pcount=0
        _auth_ticks=0

        for _si in "${!E_SIDX[@]}"; do
            _e="${E_EPOCH[$_si]:-0}"
            _pc="${E_PCOUNT[$_si]:-0}"
            _tk="${E_TICKS[$_si]:-0}"
            if [[ "$_e" -gt "$_auth_epoch" ]] || \
               [[ "$_e" -eq "$_auth_epoch" && "$_pc" -gt "$_auth_pcount" ]] || \
               [[ "$_e" -eq "$_auth_epoch" && "$_pc" -eq "$_auth_pcount" && "$_tk" -gt "$_auth_ticks" ]]; then
                _auth_si="$_si"
                _auth_epoch="$_e"
                _auth_pcount="$_pc"
                _auth_ticks="$_tk"
            fi
        done

        [[ -z "$_auth_si" ]] && continue

        _auth_played="${E_PLAYED[$_auth_si]}"
        _auth_lplayed="${E_LPLAYED[$_auth_si]}"
        _auth_pcount="${E_PCOUNT[$_auth_si]}"
        _auth_ticks="${E_TICKS[$_auth_si]}"

        # Push to servers with older state OR no state at all
        for _si in "${!U_IDX[@]}"; do
            [[ "$_si" == "$_auth_si" ]] && continue
            _their_epoch="${E_EPOCH[$_si]:-0}"
            _their_played="${E_PLAYED[$_si]:-false}"

            # Skip if they already have the same/newer state
            if [[ "$_their_epoch" -ge "$_auth_epoch" ]] && \
               [[ "$_their_played" == "$_auth_played" ]]; then
                log "  SKIP  $_pkey → ${SRV_NAME[$_si]} already up to date"
                (( TOTAL_SKIPPED++ ))
                continue
            fi

            _uid="${U_UID[$_si]}"
            _iid="${E_IID[$_si]:-}"   # might not exist on this server yet

            # Find item ID on target server by provider key if not in our map
            if [[ -z "$_iid" ]]; then
                _ptype="${_pkey%%:*}"
                _pval="${_pkey##*:}"
                case "$_ptype" in
                    imdb)   _search_field="imdb.${_pval}" ;;
                    tmdb)   _search_field="tmdb.${_pval##movie:}" ;;
                    tvdb)
                        # _pkey format: tvdb:ep:{tvdb_id}:s{season}e{ep}
                        # ##*: gives "s7e2" (wrong); strip prefix then first :
                        _tvdb_num="${_pkey#tvdb:ep:}"; _tvdb_num="${_tvdb_num%%:*}"
                        _search_field="tvdb.${_tvdb_num}"
                        ;;
                    mb)     _search_field="" ;;  # skip music if not found
                esac

                if [[ -n "$_search_field" ]]; then
                    _iid=$(_api_get "${SRV_URL[$_si]}" "${SRV_KEY[$_si]}" \
                        "Items?AnyProviderIdEquals=${_search_field}&Recursive=true&Fields=ProviderIds&Limit=1" 2>/dev/null \
                        | jq -r '.Items[0].Id // empty' 2>/dev/null)
                fi
                [[ -z "$_iid" ]] && log "  SKIP  $_pkey → ${SRV_NAME[$_si]} item not found on server" && continue
            fi

            log "  SYNC  $_pkey → ${SRV_NAME[$_si]} (auth: ${SRV_NAME[$_auth_si]}, epoch: $_auth_epoch)"

            if [[ "$DRY_RUN" == true ]]; then
                echo "  DRY RUN: would sync $_pkey → ${SRV_NAME[$_si]} user=$lname played=$_auth_played date=$_auth_lplayed"
                (( TOTAL_SYNCED++ ))
                continue
            fi

            # Write state to target server
            if [[ "$_auth_played" == "true" ]]; then
                # Mark as played with date
                _date_param=""
                if [[ "$_auth_lplayed" != "null" && -n "$_auth_lplayed" ]]; then
                    # Emby's PlayedItems endpoint rejects 7-digit fractional seconds (.0000000)
                    # with HTTP 500; strip to whole seconds before encoding
                    if [[ "$_auth_lplayed" == *.* ]]; then
                        _lp="${_auth_lplayed%.*}"
                        [[ "$_auth_lplayed" == *Z ]] && _lp+="Z"
                    else
                        _lp="$_auth_lplayed"
                    fi
                    _date_param="?DatePlayed=${_lp//[: ]/%3A}"
                fi
                _http=$(_api_post "${SRV_URL[$_si]}" "${SRV_KEY[$_si]}" \
                    "Users/${_uid}/PlayedItems/${_iid}${_date_param}")
                if [[ "$_http" == "200" || "$_http" == "201" ]]; then
                    success "  ✓  $_pkey → ${SRV_NAME[$_si]} marked played"
                    (( TOTAL_SYNCED++ ))
                else
                    warn "  ✗  $_pkey → ${SRV_NAME[$_si]} failed (HTTP ${_http:-err})"
                    (( TOTAL_ERRORS++ ))
                fi
            else
                # Sync resume position only
                _ticks_int=$(( ${_auth_ticks:-0} ))
                if [[ "$_ticks_int" -gt 0 ]]; then
                    _payload="{\"PlaybackPositionTicks\":${_ticks_int}}"
                    _http=$(_api_post "${SRV_URL[$_si]}" "${SRV_KEY[$_si]}" \
                        "Users/${_uid}/Items/${_iid}/UserData" "$_payload")
                    if [[ "$_http" == "200" || "$_http" == "204" ]]; then
                        success "  ✓  $_pkey → ${SRV_NAME[$_si]} resume synced ($(_ticks_to_sec "$_ticks_int")s)"
                        (( TOTAL_SYNCED++ ))
                    else
                        warn "  ✗  $_pkey → ${SRV_NAME[$_si]} resume sync failed (HTTP ${_http:-err})"
                        (( TOTAL_ERRORS++ ))
                    fi
                fi
            fi
        done

        unset E_EPOCH E_PLAYED E_PCOUNT E_TICKS E_IID E_LPLAYED E_SIDX
    done

    unset ITEM_MAP U_IDX U_UID
done

# ==============================================================================================
# ━━━ Summary ━━━
# ==============================================================================================
END=$(date +%s)
echo ""
echo "━━━━━ $ICON_SUMMARY PLAY STATE SYNC SUMMARY ━━━━━"
echo "$ICON_TIME  Duration:  $(format_duration $(( END - START )))"
echo "$ICON_DONE  Synced:    $TOTAL_SYNCED"
[[ "$TOTAL_SKIPPED" -gt 0 ]] && echo "$ICON_RUNNING  Skipped:   $TOTAL_SKIPPED (already current)"
[[ "$TOTAL_ERRORS"  -gt 0 ]] && echo "$ICON_ERROR  Errors:    $TOTAL_ERRORS"

if [[ "$DRY_RUN" == true ]]; then
    warn "DRY RUN — no changes written"
elif [[ "$TOTAL_ERRORS" -eq 0 ]]; then
    success "Done ✅"
else
    warn "Done with $TOTAL_ERRORS error(s)"
fi