#!/usr/bin/env bash
set -euo pipefail
# POS: share smb-server — Manage the Samba server (status, share/unshare exports, users, enable/disable)
# POS_SUBCMDS: status share unshare list adduser deluser reload enable disable menu

source "$(dirname "$0")/../lib/common.sh" 2>/dev/null || source "$(dirname "$0")/common.sh"
source "$(dirname "$0")/../lib/notify.sh" 2>/dev/null || source "$(dirname "$0")/notify.sh"
source "$(dirname "$0")/../lib/share-lib.sh" 2>/dev/null || source "$(dirname "$0")/share-lib.sh"

command -v smbd &>/dev/null || err "smbd not found (install samba)"
command -v smbcontrol &>/dev/null || err "smbcontrol not found (install samba)"
command -v testparm &>/dev/null || err "testparm not found (install samba)"
command -v smbpasswd &>/dev/null || err "smbpasswd not found (install samba)"

usage() {
    cat <<EOF
Usage: pos share smb-server <command> [args]

Manage the Samba server (smbd, /etc/samba/smb.conf).

Commands:
  status              Show server status + current shares + users
  share <path> [name]  Add or update a share (default name: folder basename)
  unshare <name>      Remove a share and reload
  list                Show current shares
  adduser <user>      Create a Samba user (prompts for password)
  deluser <user>      Remove a Samba user
  reload              Validate smb.conf and reload the server
  enable              Start smbd and enable it on boot
  disable             Stop smbd and disable it on boot

Options for share:
  --read-only         Export read-only
  --guest             Allow guest access (ANY user on the network — warns)
  --users <u1,u2>     Restrict to these Samba users (comma-separated)

Examples:
  pos share smb-server share /mnt/hdd media --users bob,alice
  pos share smb-server share /mnt/hdd/media --read-only
  pos share smb-server adduser bob
  pos share smb-server list
  pos share smb-server unshare media
EOF
    exit 0
}

SMB_CONF="${SMB_CONF:-/etc/samba/smb.conf}"

cmd="${1:-}"
case "$cmd" in
    -h|--help) usage ;;
    ""|menu|status|share|unshare|list|adduser|deluser|reload|enable|disable) ;;
    *) err "Unknown command '$cmd' (see --help)" ;;
esac

require_root_dir() {
    local path="$1"
    case "$path" in
        /*) ;;
        *) err "Path must be absolute: $path" ;;
    esac
    [ -d "$path" ] || err "Path not found: $path"
}

validate_share_name() {
    case "$1" in
        *[!A-Za-z0-9._-]*) err "Invalid share name '$1' — use letters, digits, . _ -" ;;
    esac
}

# Warn when any ancestor of the share path lacks other:+x — Samba clients
# traverse as the authenticated user, so a 700 home dir yields
# NT_STATUS_ACCESS_DENIED no matter what smb.conf says. (Sticky dirs like
# /tmp show 't' in the other-execute slot — still traversable.)
check_traversal() {
    local p="$1" blocked="" m
    while [ "$p" != "/" ]; do
        m="$(stat -c '%A' "$p" 2>/dev/null | cut -c10)"
        [ "$m" = "x" ] || [ "$m" = "t" ] || blocked="${blocked:+$blocked, }$p"
        p="$(dirname "$p")"
    done
    [ -z "$blocked" ] || warn "Samba can't traverse: $blocked (missing other:+x) — clients get NT_STATUS_ACCESS_DENIED. Fix: chmod o+x <dir>"
}

# Warn for --users entries missing from the Samba passdb (pdbedit/smbpasswd).
check_samba_users() {
    local list="$1" sdb u missing=""
    if sdb="$(sudo pdbedit -L 2>/dev/null | cut -d: -f1)"; then
        for u in ${list//,/ }; do
            grep -qxF "$u" <<<"$sdb" || missing="${missing:+$missing, }$u"
        done
    fi
    [ -z "$missing" ] || warn "user(s) not in the Samba passdb: $missing — clients get NT_STATUS_ACCESS_DENIED. Add them: pos share smb-server adduser <user> (needs a system user)"
}

# Validate smb.conf with testparm, then hot-reload smbd if it is running.
reload_config() {
    testparm -s "$SMB_CONF" >/dev/null || err "smb.conf is invalid — changes not loaded (fix with 'pos share smb-server reload')"
    if systemctl is-active --quiet smbd 2>/dev/null; then
        sudo smbcontrol smbd reload-config
        log "smbd config reloaded"
    else
        warn "smbd not running — config validated but not loaded (enable with 'pos share smb-server enable')"
    fi
}

# rc 0 = Samba reachable through the firewall (or nothing to check),
# rc 1 = ufw active but no Samba rule → clients can't reach 139/445.
# Thin wrapper: the decision core lives in lib/share-lib.sh.
ufw_blocks_samba() {
    share_ufw_blocks_ports 'samba|(^|[^0-9])(137|138|139|445)([^0-9]|$)'
}

# Warn when another managed share already exports the same path under a
# different name (two names for one folder = confusing debug sessions).
dup_path_share() {
    local path="$1" name="$2" dup
    dup="$(awk -v want="$path" -v cur="$name" '
        $1 == "#" && $2 == ">>>" { n = $5; inb = 1 }
        $0 == "# <<< end pos-managed share" { inb = 0 }
        inb && $1 == "path" && $3 == want && n != cur { print n; exit }
    ' "$SMB_CONF")"
    [ -n "$dup" ] && warn "Path already shared as [$dup] — creating a second export of the same folder.
  Prefer updating that one: pos share smb-server share $path $dup"
    return 0
}

list_shares() {
    local out
    out="$(testparm -s "$SMB_CONF" 2>/dev/null | grep -F '[' || true)"
    if [ -z "$out" ]; then
        echo " (none)"
        return
    fi
    printf '%s\n' "$out" | grep -Fv '[global]' | sed 's/\[\(.*\)\]/  \1/'
}

cmd_status() {
    if systemctl is-active --quiet smbd 2>/dev/null; then
        ok "smbd: running"
    else
        warn "smbd: not running (enable with 'pos share smb-server enable')"
    fi
    echo
    section "Shares"
    list_shares
    echo
    section "Users"
    sudo pdbedit -L 2>/dev/null | cut -d: -f1 | sed 's/^/  /' || echo " (none)"
    echo
    section "Ports"
    if ss -tln 2>/dev/null | awk '$4 ~ /:(139|445)$/ { f = 1 } END { exit !f }'; then
        ok "smbd listening on :139/:445"
    else
        warn "nothing listening on :139/:445 locally (smbd down or bound elsewhere)"
    fi
    if command -v ufw >/dev/null 2>&1 && sudo ufw status 2>/dev/null | grep -q "^Status: active"; then
        if ufw_blocks_samba; then
            warn "firewall: ufw active, NO Samba rule — clients can't connect. Fix: sudo ufw allow Samba"
        else
            ok "firewall: ufw active, Samba allowed"
        fi
    else
        ok "firewall: no active ufw — nothing blocking SMB ports"
    fi
}

cmd_share() {
    local path="$1"
    [ -n "$path" ] || err "Usage: pos share smb-server share <path> [name] [--read-only|--guest|--users u1,u2]"
    case "$path" in
        -*) err "Usage: pos share smb-server share <path> [name] [--read-only|--guest|--users u1,u2]" ;;
    esac
    require_root_dir "$path"
    check_traversal "$path"
    [ -f "$SMB_CONF" ] || err "No smb.conf at $SMB_CONF (is samba installed?)"

    shift
    local name="" ro=0 guest=0 users=""
    while [ $# -gt 0 ]; do
        case "$1" in
            --read-only) ro=1; shift ;;
            --guest) guest=1; shift ;;
            --users) [ $# -ge 2 ] || err "--users needs a value"; users="$2"; shift 2 ;;
            -*) err "unknown option '$1'" ;;
            *) name="$1"; shift ;;
        esac
    done
    name="${name:-$(basename "$path")}"
    validate_share_name "$name"
    dup_path_share "$path" "$name"

    if [ "$guest" -eq 1 ]; then
        warn "guest access on — ANY network user can access $path. Restrict with --users."
    elif [ -z "$users" ]; then
        warn "No valid users — any Samba account can access $path. Restrict with --users u1,u2."
    fi
    [ -n "$users" ] && check_samba_users "$users"
    if ufw_blocks_samba; then
        warn "ufw is active but allows no Samba traffic — clients can't reach ports 139/445.
  Fix on this machine: sudo ufw allow Samba"
    fi

    local ro_val=no guest_val=no block tmp
    [ "$ro" -eq 1 ] && ro_val=yes
    [ "$guest" -eq 1 ] && guest_val=yes
    block="[$name]
   path = $path
   browseable = yes
   read only = $ro_val
   guest ok = $guest_val"
    [ -n "$users" ] && block="$block
   valid users = $users"

    tmp="$(mktemp)"
    awk -v s="# >>> pos-managed share: $name" -v e="# <<< end pos-managed share" '
        $0 == s {inblock=1}
        $0 == e && inblock == 1 {inblock=0; next}
        !inblock {print}
    ' "$SMB_CONF" > "$tmp"
    {
        echo
        echo "# >>> pos-managed share: $name"
        printf '%s\n' "$block"
        echo "# <<< end pos-managed share"
    } >> "$tmp"

    testparm -s "$tmp" >/dev/null || { rm -f "$tmp"; err "Invalid smb.conf — changes not applied (see testparm -s $SMB_CONF)"; }
    sudo cp "$tmp" "$SMB_CONF"
    rm -f "$tmp"
    reload_config
    log "Share added: [$name] → $path"
    notify_send "SMB share added: $name ($path)"
}

cmd_unshare() {
    local name="$1" tmp
    validate_share_name "$name"
    [ -f "$SMB_CONF" ] || err "No smb.conf at $SMB_CONF (is samba installed?)"

    if ! grep -Fq "# >>> pos-managed share: $name" "$SMB_CONF"; then
        warn "No share '$name' found in $SMB_CONF"
        exit 0
    fi

    tmp="$(mktemp)"
    awk -v s="# >>> pos-managed share: $name" -v e="# <<< end pos-managed share" '
        $0 == s {inblock=1}
        $0 == e && inblock == 1 {inblock=0; next}
        !inblock {print}
    ' "$SMB_CONF" > "$tmp"
    sudo cp "$tmp" "$SMB_CONF"
    rm -f "$tmp"
    reload_config
    log "Removed share: $name"
    notify_send "SMB share removed: $name"
}

cmd_list() {
    list_shares
}

cmd_adduser() {
    local user="$1"
    [ -n "$user" ] || err "Usage: pos share smb-server adduser <user>"
    id -u "$user" >/dev/null 2>&1 || err "No system user '$user' — create it first (e.g. sudo adduser $user)"
    if sudo pdbedit -L 2>/dev/null | cut -d: -f1 | grep -qxF "$user"; then
        warn "'$user' already has a Samba account — nothing to do."
        log "Reset the password with: sudo smbpasswd $user"
        exit 0
    fi
    sudo smbpasswd -a "$user"
    log "Samba user added: $user"
    notify_send "SMB user added: $user"
}

cmd_deluser() {
    local user="$1"
    [ -n "$user" ] || err "Usage: pos share smb-server deluser <user>"
    if ! sudo pdbedit -L 2>/dev/null | cut -d: -f1 | grep -qxF "$user"; then
        log "'$user' is not a Samba user — nothing to remove"
        exit 0
    fi
    sudo smbpasswd -x "$user"
    log "Samba user removed: $user"
    notify_send "SMB user removed: $user"
}

cmd_reload() {
    reload_config
}

cmd_enable() {
    sudo systemctl enable --now smbd
    log "smbd enabled (starts on boot)"
    notify_send "SMB server enabled"
}

cmd_disable() {
    sudo systemctl disable --now smbd
    log "smbd disabled (will not start on boot)"
    notify_send "SMB server disabled"
}

# ── Interactive menu flows ─────────────────────────────────────
menu_pick_folder() { # stdout: folder path · rc 1 cancelled
    local idx dir cand
    local -a cands=()
    if mapfile -t cands < <(share_folder_candidates) && [ "${#cands[@]}" -gt 0 ]; then
        if idx="$(share_pick "Share which folder?" "${cands[@]}")"; then
            cand="${cands[$((idx - 1))]}"
            dir="${cand%% (*}"          # strip "(mounted fstype)" annotation
            [ -d "$dir" ] || { warn "Folder vanished: $dir"; return 1; }
            echo "$dir"
            return 0
        fi
        return 1
    fi
    dir="$(share_ask_value "Folder to share (absolute path)")" || return 1
    [ -n "$dir" ] || { warn "No folder given"; return 1; }
    echo "$dir"
}

menu_share() {
    local dir name users
    local -a args=()
    dir="$(menu_pick_folder)" || return 1
    name="$(share_ask_value "Share name" "$(basename "$dir")")" || return 1
    [ -n "$name" ] || name="$(basename "$dir")"

    if confirm "Read-only share?" n; then
        args+=(--read-only)
    fi
    if confirm "Guest access (ANY network user, no login)?" n; then
        args+=(--guest)
    else
        users="$(share_ask_value "Restrict to Samba users (comma-separated, empty = any account)")" || return 1
        [ -n "$users" ] && args+=(--users "$users")
    fi
    cmd_share "$dir" "$name" ${args[@]+"${args[@]}"}
}

menu_unshare() {
    local idx name
    local -a names=()
    if mapfile -t names < <(awk '/^# >>> pos-managed share: /{ sub(/^# >>> pos-managed share: /, ""); print }' "$SMB_CONF" 2>/dev/null) &&
        [ "${#names[@]}" -gt 0 ]; then
        idx="$(share_pick "Remove which share?" "${names[@]}")" || return 1
        name="${names[$((idx - 1))]}"
    else
        name="$(share_ask_value "Share name to remove")" || return 1
        [ -n "$name" ] || return 1
    fi
    cmd_unshare "$name"
}

menu_adduser() {
    local user
    user="$(share_ask_value "System user to give a Samba account")" || return 1
    [ -n "$user" ] || return 1
    cmd_adduser "$user"
}

menu_deluser() {
    local idx user
    local -a users=()
    if mapfile -t users < <(sudo pdbedit -L 2>/dev/null | cut -d: -f1) &&
        [ "${#users[@]}" -gt 0 ]; then
        idx="$(share_pick "Remove which Samba user?" "${users[@]}")" || return 1
        user="${users[$((idx - 1))]}"
    else
        user="$(share_ask_value "Samba user to remove")" || return 1
        [ -n "$user" ] || return 1
    fi
    cmd_deluser "$user"
}

run_menu() {
    share_menu_guard || exit 1
    while true; do
        local choice
        choice="$(share_menu_run "Samba server" \
            "Show status (shares/users/ports/firewall)" \
            "Share a folder" \
            "Remove a share" \
            "List current shares" \
            "Add a Samba user" \
            "Remove a Samba user" \
            "Validate + reload config" \
            "Enable service on boot" \
            "Disable service")" || return 0
        case "$choice" in
            1) cmd_status ;;
            2) menu_share ;;
            3) menu_unshare ;;
            4) cmd_list ;;
            5) menu_adduser ;;
            6) menu_deluser ;;
            7) cmd_reload ;;
            8) cmd_enable ;;
            9) cmd_disable ;;
        esac
    done
}

case "$cmd" in
    ""|menu)
        run_menu
        exit 0
        ;;

    status)  cmd_status ;;

    share)
        [ $# -ge 2 ] || err "Usage: pos share smb-server share <path> [name] [--read-only|--guest|--users u1,u2]"
        cmd_share "${@:2}"
        ;;

    unshare)
        [ $# -ge 2 ] || err "Usage: pos share smb-server unshare <name>"
        cmd_unshare "$2"
        ;;

    list)    cmd_list ;;

    adduser)
        [ $# -ge 2 ] || err "Usage: pos share smb-server adduser <user>"
        cmd_adduser "$2"
        ;;

    deluser)
        [ $# -ge 2 ] || err "Usage: pos share smb-server deluser <user>"
        cmd_deluser "$2"
        ;;

    reload)  cmd_reload ;;

    enable)  cmd_enable ;;

    disable) cmd_disable ;;
esac