#!/bin/bash
# services/anki-sync-server.sh — Self-hosted Anki flashcard sync server.
# Part of the modular post-install system (sourced by setup.sh).
#
# Can also be run standalone on any machine:
#   sudo bash anki-sync-server.sh
# (Docker must already be installed when run standalone)

# ── Standalone bootstrap ──────────────────────────────────────────────────────
# Detected when the script is executed directly rather than sourced by setup.sh.
# Sets up helpers and globals, then defers execution until after the function
# definition at the bottom of this file.
if [[ "${BASH_SOURCE[0]}" == "${0}" ]]; then
    [[ "$(id -u)" == "0" ]] || { echo "Run with sudo: sudo bash $0"; exit 1; }

    _SELF_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
    _COMMON="$_SELF_DIR/../lib/common.sh"

    if [[ -f "$_COMMON" ]]; then
        # Full repo present — use the real helpers (picks up ~/docker/.config too)
        # shellcheck source=../lib/common.sh
        source "$_COMMON"
    else
        # One-off copy — inline minimal stubs so the script works without the repo
        log_info()    { echo -e "\033[0;34m[INFO]\033[0m $*"; }
        log_success() { echo -e "\033[0;32m[OK]\033[0m $*"; }
        log_warning() { echo -e "\033[1;33m[WARN]\033[0m $*"; }
        log_error()   { echo -e "\033[0;31m[ERROR]\033[0m $*" >&2; }

        require_docker() {
            command -v docker &>/dev/null || {
                log_error "Docker not found. Install it first:"
                log_error "  curl -fsSL https://get.docker.com | sudo sh"
                return 1
            }
            docker compose version &>/dev/null || {
                log_error "Docker Compose plugin missing:"
                log_error "  sudo apt-get install -y docker-compose-plugin"
                return 1
            }
        }

        ensure_docker_dir_ownership() {
            chown -R "$ACTUAL_USER:$ACTUAL_USER" "$@" 2>/dev/null || true
        }

        port_in_use() {
            local _port="$1" _proto="${2:-tcp}"
            local _flag="-tlnH"
            [ "$_proto" = "udp" ] && _flag="-ulnH"
            ss "$_flag" "sport = :${_port}" 2>/dev/null | grep -q .
        }

        find_free_port() {
            local _varname="$1" _port="$2" _proto="${3:-tcp}"
            while port_in_use "$_port" "$_proto"; do
                _port=$((_port + 1))
            done
            eval "$_varname='$_port'"
        }

        # Match common.sh's eval-based pattern so local vars in install_* are set correctly
        prompt_text() {
            local _q="$1" _def="$2" _var="$3" _r
            [[ "${UNATTENDED:-false}" == "true" ]] && { eval "$_var='$_def'"; return; }
            read -r -p "  $_q " _r
            eval "$_var='${_r:-$_def}'"
        }

        prompt_yn() {
            local _q="$1" _def="$2" _var="$3" _r
            [[ "${UNATTENDED:-false}" == "true" ]] && { eval "$_var='$_def'"; return; }
            read -r -p "  $_q " _r
            eval "$_var='${_r:-$_def}'"
        }

        prompt_reinstall_mode() {
            local _var="$1" _r
            if [[ "${UNATTENDED:-false}" == "true" ]]; then eval "$_var='cancel'"; return; fi
            echo "  Already installed."
            read -r -p "  (u)pdate / (f)resh reinstall / (c)ancel [c]: " _r
            case "${_r,,}" in
                u|update) eval "$_var='update'" ;;
                f|fresh)  eval "$_var='fresh'"  ;;
                *)        eval "$_var='cancel'" ;;
            esac
        }

        generate_password() {
            local length="${1:-32}"
            openssl rand -base64 48 | tr -dc 'a-zA-Z0-9' | head -c "$length"
        }

        configure_caddy_for_service() {
            local _name="$1" _upstream="$2" _subdomain="$3" _extra="${4:-}"
            local _caddy_dir="$DOCKER_DIR/caddy"
            local _caddyfile="$_caddy_dir/Caddyfile"
            local _display_port="${_upstream##*:}"

            # Determine mode: local Caddy, remote Caddy, or none
            local _mode="none"
            [[ -d "$_caddy_dir" ]] && _mode="local"
            [[ -n "${CADDY_REMOTE_HOST:-}" ]] && [[ "$_mode" != "local" ]] && _mode="remote"
            [[ "$_mode" == "none" ]] && {
                log_info "Access $_name directly on port $_display_port."
                return 0
            }

            echo ""
            local _do_caddy=""
            if [[ "$_mode" == "remote" ]]; then
                log_info "Remote Caddy configured (${CADDY_REMOTE_HOST})."
                log_info "A snippet file will be saved to ~/docker/caddy-snippets/."
            fi
            read -r -p "  Configure Caddy reverse proxy for $_name? [y/N]: " _do_caddy
            [[ "${_do_caddy,,}" == "y" ]] || {
                log_info "Skipping — access at: http://localhost:$_display_port"
                return 0
            }

            # Domain prompt — pre-fill from SITE_DOMAIN when available
            local _default_domain=""
            if [[ -n "${SITE_DOMAIN:-}" ]] && [[ "$SITE_DOMAIN" != "example.com" ]]; then
                _default_domain="${_subdomain}.${SITE_DOMAIN}"
                log_info "Default: $_default_domain"
            fi
            local _domain=""
            read -r -p "  Domain [${_default_domain:-required}]: " _domain
            _domain="${_domain:-$_default_domain}"
            [[ -n "$_domain" ]] || { log_warning "No domain entered — skipping Caddy."; return 0; }

            # Build upstream — remote Caddy uses host IP:port, not container name
            local _block_upstream="$_upstream"
            if [[ "$_mode" == "remote" ]]; then
                _block_upstream="${CADDY_REMOTE_HOST}:${_display_port}"
            fi

            local _site_block
            _site_block="$(cat << CBLOCK

# $_name
${_domain} {
    reverse_proxy ${_block_upstream}

    header {
        Strict-Transport-Security "max-age=31536000; includeSubDomains; preload"
        X-Content-Type-Options "nosniff"
        X-Frame-Options "SAMEORIGIN"
        Referrer-Policy "strict-origin-when-cross-origin"
    }

    log {
        output file /var/log/caddy/${_domain}.log
        format json
    }
${_extra}
}
CBLOCK
)"

            if [[ "$_mode" == "local" ]]; then
                if [[ -f "$_caddyfile" ]]; then
                    local _bk="$_caddy_dir/Caddyfile.backup.$(date +%Y%m%d-%H%M%S)"
                    cp "$_caddyfile" "$_bk"
                    log_info "Backed up Caddyfile to $(basename "$_bk")"
                else
                    touch "$_caddyfile"
                fi

                if grep -q "^${_domain}" "$_caddyfile" 2>/dev/null; then
                    log_warning "$_domain already in Caddyfile"
                    local _ow=""
                    read -r -p "  Overwrite? [y/N]: " _ow
                    [[ "${_ow,,}" == "y" ]] || { log_info "Keeping existing entry."; return 0; }
                    sed -i "/^${_domain}/,/^}/d" "$_caddyfile"
                fi

                printf '%s\n' "$_site_block" >> "$_caddyfile"
                log_success "Added $_domain to Caddyfile"
                docker exec caddy caddy fmt --overwrite /etc/caddy/Caddyfile 2>/dev/null || true
                if docker exec caddy caddy reload --config /etc/caddy/Caddyfile 2>/dev/null; then
                    log_success "$_name accessible at: https://$_domain"
                else
                    log_warning "Reload failed — check: docker logs caddy"
                    log_info "Manual reload: docker exec caddy caddy reload --config /etc/caddy/Caddyfile"
                fi
            else
                local _snippet_dir="$DOCKER_DIR/caddy-snippets"
                local _snippet_file="$_snippet_dir/${_subdomain}.caddy"
                mkdir -p "$_snippet_dir"
                printf '%s\n' "$_site_block" > "$_snippet_file"
                chown "$ACTUAL_USER:$ACTUAL_USER" "$_snippet_file" 2>/dev/null || true
                log_success "Snippet saved: $_snippet_file"
                log_info "Copy to Caddy machine:"
                log_info "  scp $_snippet_file caddy-host:~/caddy-snippets/"
                log_info "  rsync -av $_snippet_dir/ caddy-host:~/caddy-snippets/  (all at once)"
            fi
        }
        write_readme() {
            local _dir="$1"; shift
            mkdir -p "$_dir"
            cat > "$_dir/README.md"
        }
        backup_if_exists() {
            local _file="$1"
            [ -f "$_file" ] || return 0
            cp -p "$_file" "${_file}.bak.$(date +%Y%m%d-%H%M%S)" 2>/dev/null
        }
    fi

    # Globals — ACTUAL_USER/ACTUAL_HOME must come before DOCKER_DIR
    # ($HOME under sudo is /root, not the real user's home)
    ACTUAL_USER="${ACTUAL_USER:-${SUDO_USER:-$USER}}"
    ACTUAL_HOME="$(getent passwd "$ACTUAL_USER" 2>/dev/null | cut -d: -f6 || echo "${HOME:-/root}")"
    DOCKER_DIR="${DOCKER_DIR:-$ACTUAL_HOME/docker}"
    DRY_RUN="${DRY_RUN:-false}"
    UNATTENDED="${UNATTENDED:-false}"
    SITE_TZ="${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}"
    SITE_DOMAIN="${SITE_DOMAIN:-example.com}"
    SITE_CADDY_NET="${SITE_CADDY_NET:-caddy_net}"

    register_service() { :; }   # no-op — no wizard to register into
    _RUN_STANDALONE=1
fi
# ─────────────────────────────────────────────────────────────────────────────

register_service anki-sync-server utilities "Self-hosted Anki flashcard sync server (spaced repetition, syncs across devices without AnkiWeb)" 8080

# Reads the current ANKI_SYNC_USERn/ANKI_SYNC_PASSWORDn pairs out of an
# instance's .env into the caller's ANKI_USERS/ANKI_PASSWORDS arrays (bash's
# dynamic scoping means a `local` array declared in the caller is visible
# here without being passed explicitly — same assumption every other helper
# below makes). Numbering is always kept contiguous from 1 by
# _anki_rewrite_account_block, so stopping at the first missing index is
# safe — there's never a gap to skip over.
_anki_load_accounts() {
    local _dir="$1" _n=1 _u _p
    ANKI_USERS=() ANKI_PASSWORDS=()
    while true; do
        _u="$(grep "^ANKI_SYNC_USER${_n}=" "$_dir/.env" 2>/dev/null | cut -d= -f2-)"
        [ -z "$_u" ] && break
        _p="$(grep "^ANKI_SYNC_PASSWORD${_n}=" "$_dir/.env" 2>/dev/null | cut -d= -f2-)"
        ANKI_USERS+=("$_u")
        ANKI_PASSWORDS+=("$_p")
        _n=$((_n + 1))
    done
}

# Regenerates the SYNC_USERn=... lines in docker-compose.yml and the
# matching ANKI_SYNC_USERn/ANKI_SYNC_PASSWORDn pairs in .env from the
# caller's current ANKI_USERS/ANKI_PASSWORDS arrays (always renumbered
# contiguously from 1 — see _anki_load_accounts). Used by both the initial
# install and every account-management mutation (add/remove/rotate) so the
# two never drift apart, same reasoning as CLAUDE.md's shared-helper
# guidance for update vs. fresh-install codepaths. Leaves the port, Caddy
# block, and every other line in either file untouched — only lines
# matching the SYNC_USER/ANKI_SYNC_* patterns are touched.
_anki_rewrite_account_block() {
    local _dir="$1"
    local _compose="$_dir/docker-compose.yml"
    local _env="$_dir/.env"

    sed -i '/^      - SYNC_USER[0-9]\+=/d' "$_compose"
    sed -i '/^ANKI_SYNC_USER[0-9]\+=/d; /^ANKI_SYNC_PASSWORD[0-9]\+=/d' "$_env"

    local _compose_lines="" _env_lines="" i idx
    for i in "${!ANKI_USERS[@]}"; do
        idx=$((i + 1))
        _compose_lines+="      - SYNC_USER${idx}=\${ANKI_SYNC_USER${idx}}:\${ANKI_SYNC_PASSWORD${idx}}
"
        _env_lines+="ANKI_SYNC_USER${idx}=${ANKI_USERS[$i]}
ANKI_SYNC_PASSWORD${idx}=${ANKI_PASSWORDS[$i]}
"
    done

    # Insert right after the fixed SYNC_BASE anchor line — always present,
    # written by every version of this script's install flow — instead of
    # appending at the end, so the block stays grouped with SYNC_HOST/
    # SYNC_PORT/SYNC_BASE rather than drifting after `volumes:`.
    local _tmp
    _tmp="$(mktemp)"
    printf '%s' "$_compose_lines" > "$_tmp"
    sed -i "\|^      - SYNC_BASE=/data\$|r $_tmp" "$_compose"
    rm -f "$_tmp"

    printf '%s' "$_env_lines" >> "$_env"
}

# Interactive add/remove/rotate menu for an existing instance's sync
# accounts, offered from install_anki-sync-server's "already installed"
# menu. Every mutation restarts the container (`docker compose up -d`
# re-reads .env for the new/removed/rotated credentials) but never touches
# the port, Caddy config, or the image — the things CLAUDE.md's "update vs.
# fresh reinstall" convention says a non-destructive path must leave alone.
_anki_manage_accounts() {
    local _dir="$1"
    local ANKI_USERS=() ANKI_PASSWORDS=()
    while true; do
        _anki_load_accounts "$_dir"
        echo ""
        echo "  Current sync accounts:"
        local i
        for i in "${!ANKI_USERS[@]}"; do
            echo "    $((i + 1))) ${ANKI_USERS[$i]}"
        done
        [ "${#ANKI_USERS[@]}" -eq 0 ] && echo "    (none)"
        echo ""
        echo "  a) Add an account"
        echo "  r) Remove an account"
        echo "  p) Rotate (reset) an account's password"
        echo "  0) Done"
        echo ""
        local ACTION=""
        prompt_text "  Choice [a/r/p/0]:" "0" ACTION
        case "$ACTION" in
            a|A)
                if [ "${#ANKI_USERS[@]}" -ge 8 ]; then
                    log_warning "That's plenty — stopping at 8 accounts."
                    continue
                fi
                local _u=""
                prompt_text "  New username:" "" _u
                if [ -z "$_u" ]; then
                    log_warning "Name can't be empty."; continue
                fi
                ANKI_USERS+=("$_u")
                ANKI_PASSWORDS+=("$(generate_password 24)")
                _anki_rewrite_account_block "$_dir"
                ( cd "$_dir" && docker compose up -d ) \
                    && log_success "Account '$_u' added — password: ${ANKI_PASSWORDS[-1]} (also saved in $_dir/.env)" \
                    || log_warning "Container restart failed — check: docker compose -f $_dir/docker-compose.yml logs"
                ;;
            r|R)
                if [ "${#ANKI_USERS[@]}" -eq 0 ]; then
                    log_warning "No accounts to remove."; continue
                fi
                local _n=""
                prompt_text "  Remove which number?" "" _n
                if ! [[ "$_n" =~ ^[0-9]+$ ]] || [ "$_n" -lt 1 ] || [ "$_n" -gt "${#ANKI_USERS[@]}" ]; then
                    log_warning "Invalid choice."; continue
                fi
                local _removed="${ANKI_USERS[$((_n - 1))]}"
                unset 'ANKI_USERS[_n - 1]' 'ANKI_PASSWORDS[_n - 1]'
                ANKI_USERS=("${ANKI_USERS[@]}")
                ANKI_PASSWORDS=("${ANKI_PASSWORDS[@]}")
                _anki_rewrite_account_block "$_dir"
                ( cd "$_dir" && docker compose up -d ) \
                    && log_success "Account '$_removed' removed" \
                    || log_warning "Container restart failed — check: docker compose -f $_dir/docker-compose.yml logs"
                ;;
            p|P)
                if [ "${#ANKI_USERS[@]}" -eq 0 ]; then
                    log_warning "No accounts yet."; continue
                fi
                local _n=""
                prompt_text "  Rotate password for which number?" "" _n
                if ! [[ "$_n" =~ ^[0-9]+$ ]] || [ "$_n" -lt 1 ] || [ "$_n" -gt "${#ANKI_USERS[@]}" ]; then
                    log_warning "Invalid choice."; continue
                fi
                ANKI_PASSWORDS[$((_n - 1))]="$(generate_password 24)"
                _anki_rewrite_account_block "$_dir"
                ( cd "$_dir" && docker compose up -d ) \
                    && log_success "New password for '${ANKI_USERS[$((_n - 1))]}': ${ANKI_PASSWORDS[$((_n - 1))]} (also saved in $_dir/.env)" \
                    || log_warning "Container restart failed — check: docker compose -f $_dir/docker-compose.yml logs"
                ;;
            0)
                break
                ;;
            *)
                log_warning "Unrecognized choice."
                ;;
        esac
    done
}

install_anki-sync-server() {
    require_docker || return 1
    log_info "Installing Anki Sync Server..."

    # ── Instance selection ───────────────────────────────────────────────────
    # First instance keeps the plain "anki-sync-server" name/paths/port exactly
    # as before (zero behavior change for anyone with a single instance). Only
    # asking to add a second one introduces suffixed naming — same pattern as
    # services/ntfy.sh and services/homebox.sh. A second instance is a real
    # use case here (e.g. a second household wanting fully separate data on
    # the same box) even though one instance already supports multiple
    # independent accounts via SYNC_USER1/SYNC_USER2/... — see CLAUDE.md's
    # "Multi-instance services" section.
    local ANKI_DIR="$DOCKER_DIR/anki-sync-server"
    local INSTANCE_SUFFIX="" CONTAINER="anki-sync-server"
    local WEB_PORT="8080"

    if [ "$DRY_RUN" = true ]; then
        echo "[DRY-RUN] Would offer to add a new, separate instance if one already exists"
        echo "[DRY-RUN] Would create $ANKI_DIR(-<name>)"
        echo "[DRY-RUN] Would prompt for one or more sync accounts and generate passwords"
        echo "[DRY-RUN] Would write docker-compose.yml and .env"
        echo "[DRY-RUN] Would auto-scan for a free host port"
        return 0
    fi

    if [ -d "$ANKI_DIR" ]; then
        echo ""
        echo "  Anki Sync Server is already installed at $ANKI_DIR."
        echo "    1) Manage sync accounts (add / remove / rotate a password — doesn't"
        echo "       touch the port, Caddy, or the image)"
        echo "    2) Manage that install (update image / full reinstall / cancel)"
        echo "    3) Add a NEW, separate Anki Sync Server instance alongside it (its"
        echo "       own data and port — full isolation)"
        echo ""
        local _TOP_CHOICE=""
        prompt_text "  Choice [1/2/3]:" "2" _TOP_CHOICE
        if [ "$_TOP_CHOICE" = "1" ]; then
            _anki_manage_accounts "$ANKI_DIR"
            return 0
        elif [ "$_TOP_CHOICE" = "3" ]; then
            local _suffix=""
            while true; do
                prompt_text "  Short name for the new instance (letters/numbers/hyphens, e.g. 'family'):" "" _suffix
                _suffix="$(echo "$_suffix" | tr -cs 'a-zA-Z0-9-' '-' | sed 's/^-*//;s/-*$//')"
                if [ -z "$_suffix" ]; then
                    log_warning "Name can't be empty."; continue
                fi
                if [ -d "$DOCKER_DIR/anki-sync-server-$_suffix" ]; then
                    log_warning "anki-sync-server-$_suffix already exists — pick another name."; continue
                fi
                break
            done
            INSTANCE_SUFFIX="$_suffix"
            ANKI_DIR="$DOCKER_DIR/anki-sync-server-$_suffix"
            CONTAINER="anki-sync-server-$_suffix"
            log_info "New instance: $ANKI_DIR"
        else
            # "Manage that install" on THIS instance — the banner above promises
            # update/fresh/cancel, so actually offer it instead of falling straight
            # through into the same unconditional-overwrite flow as a new install.
            if [[ -f "$ANKI_DIR/docker-compose.yml" ]]; then
                local MODE=""
                prompt_reinstall_mode MODE
                case "$MODE" in
                    update)
                        log_info "Refreshing the Anki Sync Server image only — existing accounts, port, and Caddy setup are left as-is."
                        # The image is a Google distroless "nonroot" build (fixed UID/GID
                        # 65532, no shell — it can't chown anything itself at startup), so
                        # ./data has to already be writable by that exact UID or the
                        # container fails to start. Versions of this installer before this
                        # fix chowned it to ACTUAL_USER instead, which the container can't
                        # write to — re-asserting the correct ownership here repairs any
                        # install made under that bug, non-destructively (it's the
                        # installer's own bug being corrected, not a config choice, so it
                        # belongs in the non-destructive update path).
                        chown -R 65532:65532 "$ANKI_DIR/data" 2>/dev/null
                        ( cd "$ANKI_DIR" && docker compose pull && docker compose up -d ) \
                            && log_success "Anki Sync Server image refreshed" \
                            || log_warning "Refresh failed — check: docker compose -f $ANKI_DIR/docker-compose.yml logs"
                        return 0
                        ;;
                    cancel)
                        log_info "Leaving the existing install as-is."
                        return 0
                        ;;
                    fresh) ;;  # fall through to the full install flow below
                esac
            fi
        fi
    fi

    # Scan for a free port unconditionally — not just when adding an explicit
    # additional instance. A plain first install can just as easily collide
    # with an unrelated service that already claimed this default port — see
    # CLAUDE.md's "Port collision avoidance" section.
    find_free_port WEB_PORT "$WEB_PORT"

    # ── Sync accounts ─────────────────────────────────────────────────────────
    # The official sync server has no signup flow of its own — accounts are
    # fixed credentials baked in as SYNC_USER1, SYNC_USER2, ... at container
    # start, one per line in .env. Ask for at least one now (each Anki client
    # — desktop, AnkiDroid, AnkiMobile — logs in with one of these) and offer
    # to add more for other people sharing this box, since a single instance
    # already keeps each account's collection completely separate.
    local ANKI_USERS=() ANKI_PASSWORDS=()
    local _u=""
    prompt_text "  Username for your Anki sync account:" "$ACTUAL_USER" _u
    ANKI_USERS+=("$_u")
    ANKI_PASSWORDS+=("$(generate_password 24)")
    while true; do
        local _more=""
        prompt_yn "  Add another Anki sync account (e.g. for a family member)? (y/n):" "n" _more
        [[ "$_more" =~ ^[Yy]$ ]] || break
        prompt_text "  Username for the additional account:" "" _u
        if [ -z "$_u" ]; then
            log_warning "Name can't be empty."; continue
        fi
        ANKI_USERS+=("$_u")
        ANKI_PASSWORDS+=("$(generate_password 24)")
        if [ "${#ANKI_USERS[@]}" -ge 8 ]; then
            log_warning "That's plenty — stopping at 8 accounts."
            break
        fi
    done

    mkdir -p "$ANKI_DIR/data"
    ensure_docker_dir_ownership "$ANKI_DIR"
    cd "$ANKI_DIR" || return 1

    # Mirrors configure_caddy_for_service's own mode resolution (lib/common.sh):
    # explicit CADDY_MODE from the site config wins, then a local ~/docker/caddy,
    # then the legacy CADDY_REMOTE_HOST var. Only "local" joins caddy_net — a
    # remote Caddy box can't resolve container names on this host's bridge
    # network anyway; it reaches this service via the host's published port.
    local _CADDY_MODE="${CADDY_MODE:-none}"
    [ "$_CADDY_MODE" = "none" ] && [ -d "$DOCKER_DIR/caddy" ] && _CADDY_MODE="local"
    [ "$_CADDY_MODE" = "none" ] && [ -n "${CADDY_REMOTE_HOST:-}" ] && _CADDY_MODE="remote"

    local _CADDY_NET_BLOCK=""
    local _CADDY_NET_SECTION=""
    if [ "$_CADDY_MODE" = "local" ]; then
        _CADDY_NET_BLOCK="    networks:
      - caddy_net
"
        _CADDY_NET_SECTION="
networks:
  caddy_net:
    external: true
    name: ${SITE_CADDY_NET:-caddy_net}
"
    fi

    # Build the SYNC_USERn=... lines for docker-compose.yml (compose-time
    # interpolation of ${ANKI_SYNC_USERn}/${ANKI_SYNC_PASSWORDn} from .env —
    # same \${VAR} pattern services/homebox.sh uses for its own .env values)
    # and the matching ANKI_SYNC_USERn/ANKI_SYNC_PASSWORDn lines for .env.
    local _COMPOSE_USER_LINES="" _ENV_USER_LINES="" i idx
    for i in "${!ANKI_USERS[@]}"; do
        idx=$((i + 1))
        _COMPOSE_USER_LINES+="      - SYNC_USER${idx}=\${ANKI_SYNC_USER${idx}}:\${ANKI_SYNC_PASSWORD${idx}}
"
        _ENV_USER_LINES+="ANKI_SYNC_USER${idx}=${ANKI_USERS[$i]}
ANKI_SYNC_PASSWORD${idx}=${ANKI_PASSWORDS[$i]}
"
    done

    backup_if_exists docker-compose.yml
    cat > docker-compose.yml << ANKI_COMPOSE
name: $CONTAINER

services:
  anki-sync-server:
    image: afrima/anki-sync-server:latest
    container_name: $CONTAINER
    hostname: $CONTAINER
    restart: unless-stopped
    environment:
      - SYNC_HOST=0.0.0.0
      - SYNC_PORT=8080
      - SYNC_BASE=/data
${_COMPOSE_USER_LINES}    volumes:
      - ./data:/data
    ports:
      - "${WEB_PORT}:8080"
${_CADDY_NET_BLOCK}${_CADDY_NET_SECTION}
ANKI_COMPOSE

    backup_if_exists .env
    cat > .env << ANKI_ENV
TZ=${SITE_TZ:-$(cat /etc/timezone 2>/dev/null || echo UTC)}
CADDY_NET=$SITE_CADDY_NET

# One username/password pair per Anki sync account (SYNC_USER1, SYNC_USER2,
# ... in docker-compose.yml). Enter these exact values as the account on
# each Anki client (Preferences/Settings → self-hosted sync server). To add,
# remove, or reset one of these later, re-run this installer against the
# existing install and pick "Manage sync accounts" — don't hand-edit these
# lines, the matching docker-compose.yml lines have to change in lockstep.
${_ENV_USER_LINES}
ANKI_ENV
    chmod 600 .env

    chown -R "$ACTUAL_USER:$ACTUAL_USER" "$ANKI_DIR"

    # afrima/anki-sync-server is built on gcr.io/distroless/static-debian12:nonroot
    # — the process always runs as that image's fixed "nonroot" UID/GID (65532),
    # never as ACTUAL_USER, and distroless has no shell so nothing inside the
    # container can chown its own data dir at startup. Applied AFTER the
    # ACTUAL_USER chown above (not before — that call would just clobber it,
    # since it recurses over the whole $ANKI_DIR including data/) so ./data ends
    # up owned by 65532 specifically while docker-compose.yml/.env/README.md
    # (which the sysadmin edits, not the container) stay owned by ACTUAL_USER.
    # Confirmed live: getting this wrong is exactly what makes the container
    # fail to come up with a permissions error the moment it tries to create
    # anything under /data (e.g. a new user's collection).
    chown -R 65532:65532 "$ANKI_DIR/data"

    echo ""
    log_success "Anki Sync Server${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)} configured at $ANKI_DIR (port $WEB_PORT)"
    echo ""
    echo "  Sync accounts (also saved in $ANKI_DIR/.env):"
    for i in "${!ANKI_USERS[@]}"; do
        echo "    ${ANKI_USERS[$i]} / ${ANKI_PASSWORDS[$i]}"
    done
    echo ""

    # No Authelia gate here, unlike most other web-facing services in this
    # repo: this is a raw HTTP sync API that the Anki client itself talks to
    # (not a browser session), so a forward_auth login portal in front of it
    # would just break every sync request instead of protecting anything.
    # SYNC_USER1/SYNC_USER2/... above is this service's own auth boundary —
    # same reasoning as the has-built-in-auth services in CLAUDE.md, just
    # with no web UI to additionally gate.
    configure_caddy_for_service "Anki Sync Server${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)}" "${CONTAINER}:8080" "anki${INSTANCE_SUFFIX:+-$INSTANCE_SUFFIX}"

    local START=""
    prompt_yn "Start Anki Sync Server${INSTANCE_SUFFIX:+ ($INSTANCE_SUFFIX)} now? (y/n):" "y" START
    if [ "$START" = "y" ] || [ "$START" = "Y" ]; then
        docker compose up -d \
            && log_success "Anki Sync Server started" \
            || log_warning "Start failed — check: docker compose logs"
    fi

    write_readme "$ANKI_DIR" << MD
# Anki Sync Server${INSTANCE_SUFFIX:+ — $INSTANCE_SUFFIX}

Self-hosted sync server for the [Anki](https://apps.ankiweb.net/) flashcard
app — syncs your collection across devices without going through AnkiWeb.
Anki's own spaced-repetition scheduler (FSRS) gives failed cards more
repetition and correctly-recalled cards longer gaps automatically; nothing
here changes that, it's purely the sync backend.
$( [ -n "$INSTANCE_SUFFIX" ] && echo "
This is a separate, fully isolated instance (own data directory, own
accounts, own port) — not shared collections with another Anki Sync Server
instance.")

## Access
- Sync URL: $( [ -n "${CADDY_SERVICE_CONFIGURED:-}" ] && [ "$CADDY_SERVICE_CONFIGURED" = "true" ] && echo "https://${CADDY_SERVICE_DOMAIN}/" || echo "http://localhost:${WEB_PORT}/" )
- Accounts (username / password):
$(for i in "${!ANKI_USERS[@]}"; do echo "  - ${ANKI_USERS[$i]} / ${ANKI_PASSWORDS[$i]}"; done)

Enter the Sync URL and one of the above accounts on each Anki client — see
the client setup section below for exactly where.

## Data
- Collections: \`$ANKI_DIR/data\`
- Credentials: \`$ANKI_DIR/.env\` (readable by $ACTUAL_USER only)

## Manage
\`\`\`bash
cd $ANKI_DIR
docker compose up -d
docker compose down
docker compose logs -f
docker compose pull && docker compose up -d
\`\`\`

To add, remove, or reset the password of a sync account later, re-run the
installer against this install and pick **"Manage sync accounts"** —
don't hand-edit \`.env\`, the matching lines in \`docker-compose.yml\` have
to change alongside it:
\`\`\`bash
sudo ./setup.sh anki-sync-server
\`\`\`
MD

    log_info "Full client setup + Quizlet import walkthrough written to $ANKI_DIR/README.md"
}

# ── Standalone execution ───────────────────────────────────────────────────
if [[ "${_RUN_STANDALONE:-0}" == "1" ]]; then
    install_anki-sync-server
fi