#!/bin/bash
set -Eeuo pipefail

INSTALL_VERSION=2
ACTION=install
case "${1:-}" in
    '') ;;
    --check) ACTION=check ;;
    --dry-run) ACTION=dry-run ;;
    --repair) ACTION=repair ;;
    -h|--help) echo "Usage: sudo ./install.sh [--check|--dry-run|--repair]"; exit 0 ;;
    *) echo "Usage: sudo ./install.sh [--check|--dry-run|--repair]" >&2; exit 2 ;;
esac
[ "$#" -le 1 ] || { echo "Only one installer action may be specified." >&2; exit 2; }

SOURCE_DIR=$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)
source "$SOURCE_DIR/usr/local/lib/pivilion/common.sh"
pivilion_load_config || exit "$PIVILION_E_CONFIG"

cat <<'PIVILION_LOGO'

Welcome to Pivilion!

@@@@@@@@@@@@@@@@@@@
@@@@@@, &@& *@@@@@@
@@@@@@@.   .@@@@@@@
@@@@   .@@@.   @@@@
@   &@@@@.@@@@#   @
@  @ . #@@@# . @  @
@   @@@, # ,@@@   @
@@,      @      ,@@
@@@@@#@@@@@@@#@@@@@

PIVILION_LOGO

if [ "$ACTION" != dry-run ] && [ "$(id -u)" -ne 0 ]; then
    echo "Run this installer with sudo: sudo ./install.sh ${1:-}" >&2
    exit "$PIVILION_E_INSTALL"
fi

export DEBIAN_FRONTEND=noninteractive
BACKUP_DIR=""
TRANSACTION_ACTIVE=0
declare -a MANAGED_PATHS=(
    /etc/pivilion.defaults /etc/pivilion.php /etc/profile.d/pivilion-motd.sh /etc/issue.d/90-pivilion.issue
    /etc/apache2/ports.conf /etc/apache2/conf-available/pivilion.conf
    /etc/apache2/sites-available/000-default.conf /etc/apache2/sites-available/000-upload.conf
    /etc/apache2/conf-enabled/pivilion.conf /etc/apache2/sites-enabled/000-default.conf
    /etc/tor/torrc /etc/tor/torrc.d/pivilion.conf
    /etc/systemd/system/pivilion-mode.service /etc/systemd/system/pivilion-dnsmasq.service
    /etc/systemd/system/pivilion-hostapd.service /etc/systemd/system/pivilion-boot-greeter.service
    /etc/systemd/system/pivilion-login-banner.service /etc/rc.local
    /usr/local/lib/pivilion /usr/local/bin/pivilion /usr/local/bin/pivilion-diagnose
    /usr/local/bin/hotspot /usr/local/bin/onion /usr/local/bin/pikey /usr/local/bin/generator
    /usr/local/bin/static /usr/local/bin/hotglue /usr/local/bin/htaccess
    /var/lib/pivilion/install-state
    /etc/php/7.4/apache2/conf.d/99-pivilion.ini
    /etc/php/8.2/apache2/conf.d/99-pivilion.ini
    /etc/php/8.4/apache2/conf.d/99-pivilion.ini
)

log() { printf '==> %s\n' "$*"; }
warn() { printf 'WARNING: %s\n' "$*" >&2; }

preflight() {
    local codename free_kb iface package
    log "Running preflight checks"
    [ -r /etc/os-release ] || { echo "Cannot identify the operating system." >&2; return "$PIVILION_E_INSTALL"; }
    . /etc/os-release
    codename=${VERSION_CODENAME:-unknown}
    case "$codename" in bullseye|bookworm|trixie) ;; *) echo "Unsupported OS codename: $codename" >&2; return "$PIVILION_E_INSTALL" ;; esac
    getent passwd "$PIVILION_USER" >/dev/null || return "$PIVILION_E_CONFIG"
    [ -d "$PIVILION_HOME" ] || { echo "Configured home does not exist: $PIVILION_HOME" >&2; return "$PIVILION_E_CONFIG"; }
    free_kb=$(df -Pk / | awk 'NR == 2 {print $4}')
    [ "${free_kb:-0}" -ge 524288 ] || { echo "At least 512 MiB free space is required." >&2; return "$PIVILION_E_INSTALL"; }
    iface=$(pivilion_wifi_interface)
    [ -n "$iface" ] || { echo "No Wi-Fi interface found." >&2; return "$PIVILION_E_HARDWARE"; }
    [ -d "/sys/class/net/$iface" ] || { echo "Configured Wi-Fi interface does not exist: $iface" >&2; return "$PIVILION_E_HARDWARE"; }
    if command -v iw >/dev/null 2>&1; then
        local phy
        phy=$(iw dev "$iface" info 2>/dev/null | awk '$1 == "wiphy" {print "phy" $2; exit}')
        [ -z "$phy" ] || iw phy "$phy" info 2>/dev/null | grep -Eq '^[[:space:]]*\* AP$' || warn "$iface does not advertise AP mode; hotspot activation will fail safely."
    fi
    if ss -H -ltn 'sport = :80' 2>/dev/null | grep -q .; then warn "Port 80 is currently occupied; this is expected only when Apache is already installed."; fi
    if ss -H -lntu 'sport = :53' 2>/dev/null | grep -Eq '(0\.0\.0\.0|\*):53'; then warn "A wildcard DNS listener may conflict with captive mode."; fi
    if command -v apt-cache >/dev/null 2>&1; then
        for package in apache2 php tor dnsmasq hostapd nftables network-manager; do
            apt-cache show "$package" >/dev/null 2>&1 || warn "Package metadata is unavailable for $package; apt-get update may be required."
        done
    fi
    log "Preflight passed for $codename using interface $iface"
}

is_networkmanager_system() {
    command -v nmcli >/dev/null 2>&1 && { systemctl is-enabled --quiet NetworkManager 2>/dev/null || systemctl is-active --quiet NetworkManager 2>/dev/null; }
}

install_packages() {
    local packages=(apache2 libapache2-mod-php php php-cli tor dnsmasq dnsutils hostapd nftables iproute2 iw rfkill curl wget unzip wpasupplicant)
    log "Installing required packages"
    apt-get update
    apt-get install -y "${packages[@]}"
    if is_networkmanager_system; then
        log "Using NetworkManager"
    elif command -v dhcpcd >/dev/null 2>&1 || dpkg-query -W dhcpcd5 >/dev/null 2>&1; then
        apt-get install -y dhcpcd5
        log "Using dhcpcd with dedicated Pivilion hostapd"
    else
        apt-get install -y network-manager
        systemctl enable NetworkManager
        log "Installed NetworkManager because no supported backend was active"
    fi
}

backup_managed_files() {
    local path relative
    install -d -m 0700 /var/backups/pivilion
    BACKUP_DIR=$(mktemp -d /var/backups/pivilion/install-$(date +%Y%m%d-%H%M%S).XXXXXX)
    install -d -m 0700 "$BACKUP_DIR/files"
    : > "$BACKUP_DIR/present"; : > "$BACKUP_DIR/missing"; : > "$BACKUP_DIR/enabled-services"; : > "$BACKUP_DIR/active-services"
    for service in apache2 pivilion-mode.service pivilion-boot-greeter.service pivilion-login-banner.service pivilion-dnsmasq.service pivilion-hostapd.service tor.service tor@default.service; do
        systemctl is-enabled --quiet "$service" 2>/dev/null && printf '%s\n' "$service" >> "$BACKUP_DIR/enabled-services" || true
        systemctl is-active --quiet "$service" 2>/dev/null && printf '%s\n' "$service" >> "$BACKUP_DIR/active-services" || true
    done
    for path in "${MANAGED_PATHS[@]}"; do
        relative=${path#/}
        if [ -e "$path" ] || [ -L "$path" ]; then
            printf '%s\n' "$path" >> "$BACKUP_DIR/present"
            install -d -m 0700 "$BACKUP_DIR/files/$(dirname "$relative")"
            cp -a "$path" "$BACKUP_DIR/files/$relative"
        else
            printf '%s\n' "$path" >> "$BACKUP_DIR/missing"
        fi
    done
    TRANSACTION_ACTIVE=1
    log "Configuration backup created at $BACKUP_DIR"
}

rollback() {
    local rc=$? path relative service
    trap - ERR INT TERM
    [ "$TRANSACTION_ACTIVE" -eq 1 ] || exit "$rc"
    warn "Installation failed; restoring managed configuration from $BACKUP_DIR"
    while IFS= read -r path; do [ -n "$path" ] && rm -rf -- "$path"; done < "$BACKUP_DIR/missing"
    while IFS= read -r path; do
        [ -n "$path" ] || continue
        relative=${path#/}; rm -rf -- "$path"; install -d -m 0755 "$(dirname "$path")"; cp -a "$BACKUP_DIR/files/$relative" "$path"
    done < "$BACKUP_DIR/present"
    systemctl daemon-reload 2>/dev/null || true
    systemctl disable apache2 pivilion-mode.service pivilion-boot-greeter.service pivilion-login-banner.service tor.service tor@default.service 2>/dev/null || true
    while IFS= read -r path; do [ -n "$path" ] && systemctl enable "$path" 2>/dev/null || true; done < "$BACKUP_DIR/enabled-services"
    for service in apache2 pivilion-mode.service pivilion-boot-greeter.service pivilion-login-banner.service pivilion-dnsmasq.service pivilion-hostapd.service tor.service tor@default.service; do
        grep -Fqx "$service" "$BACKUP_DIR/active-services" || systemctl stop "$service" 2>/dev/null || true
    done
    while IFS= read -r service; do [ -n "$service" ] && systemctl start "$service" 2>/dev/null || true; done < "$BACKUP_DIR/active-services"
    apache2ctl configtest >/dev/null 2>&1 && systemctl reload apache2 2>/dev/null || true
    warn "Rollback complete. Package installations were retained."
    exit "$rc"
}
trap rollback ERR INT TERM

atomic_from_stdin() {
    local destination=$1 mode=${2:-0644} tmp
    install -d -m 0755 "$(dirname "$destination")"
    tmp=$(mktemp "$(dirname "$destination")/.pivilion.XXXXXX")
    cat > "$tmp"; chmod "$mode" "$tmp"; mv -f "$tmp" "$destination"
}

deploy_files() {
    local php_version
    log "Deploying Pivilion files"
    install -d -m 0755 /usr/local/lib/pivilion /usr/local/bin /etc/systemd/system /etc/tor/torrc.d /etc/profile.d /var/lib/pivilion
    install -m 0644 "$SOURCE_DIR/usr/local/lib/pivilion/common.sh" /usr/local/lib/pivilion/common.sh
    install -m 0755 "$SOURCE_DIR/usr/local/lib/pivilion/mode.sh" "$SOURCE_DIR/usr/local/lib/pivilion/diagnose.sh" \
        "$SOURCE_DIR/usr/local/lib/pivilion/issue-banner.sh" /usr/local/lib/pivilion/
    install -m 0755 "$SOURCE_DIR"/usr/local/bin/* /usr/local/bin/
    install -m 0644 "$SOURCE_DIR"/etc/systemd/system/*.service /etc/systemd/system/
    install -m 0644 "$SOURCE_DIR/etc/tor/torrc.d/pivilion.conf" /etc/tor/torrc.d/pivilion.conf
    install -m 0644 "$SOURCE_DIR/etc/profile.d/pivilion-motd.sh" /etc/profile.d/pivilion-motd.sh

    atomic_from_stdin /etc/pivilion.defaults <<EOF
PIVILION_USER=$PIVILION_USER
PIVILION_HOME=$PIVILION_HOME
PIVILION_DIR=$PIVILION_DIR
PIVILION_WEBROOT=$PIVILION_WEBROOT
PIVILION_MODE=$PIVILION_MODE
PIVILION_HOTSPOT_SSID=$PIVILION_HOTSPOT_SSID
PIVILION_WIFI_INTERFACE=$PIVILION_WIFI_INTERFACE
EOF

    install -d -m 0755 -o "$PIVILION_USER" -g "$PIVILION_GROUP" "$PIVILION_DIR" "$PIVILION_DIR/config"
    cp -a "$SOURCE_DIR/home/pi/pivilion/config/." "$PIVILION_DIR/config/"
    chown -R "$PIVILION_USER:$PIVILION_GROUP" "$PIVILION_DIR/config"
    install -d -m 0755 -o "$PIVILION_USER" -g "$PIVILION_GROUP" "$PIVILION_DIR/static" "$PIVILION_DIR/hotglue" "$PIVILION_DIR/hotglue/backup"
    [ -s "$PIVILION_DIR/mode" ] || pivilion_set_mode "$PIVILION_MODE"
    [ -e "$PIVILION_DIR/torname" ] || install -m 0644 -o "$PIVILION_USER" -g "$PIVILION_GROUP" /dev/null "$PIVILION_DIR/torname"

    install -d -m 2775 -o www-data -g www-data "$PIVILION_WEBROOT" "$PIVILION_WEBROOT/gen"
    cp -a "$SOURCE_DIR/var/www/html/pivilion/scripts" "$SOURCE_DIR/var/www/html/pivilion/images" "$SOURCE_DIR/var/www/html/pivilion/skeleton" "$PIVILION_WEBROOT/"
    install -m 0664 -o www-data -g www-data "$SOURCE_DIR/var/www/html/pivilion/gen.php" "$PIVILION_WEBROOT/gen.php"
    install -m 0644 -o www-data -g www-data "$SOURCE_DIR/var/www/html/pivilion/index.html" "$SOURCE_DIR/var/www/html/pivilion/pi-logo_128.png" "$PIVILION_WEBROOT/"
    if [ ! -e "$PIVILION_WEBROOT/gen/index.php" ]; then cp -a "$SOURCE_DIR/var/www/html/pivilion/gen/." "$PIVILION_WEBROOT/gen/"; fi
    chown -R www-data:www-data "$PIVILION_WEBROOT/scripts" "$PIVILION_WEBROOT/images" "$PIVILION_WEBROOT/skeleton" "$PIVILION_WEBROOT/gen"

    atomic_from_stdin /etc/pivilion.php <<EOF
<?php
define('PIVILION_DIR', ${PIVILION_DIR@Q});
define('PIVILION_WEBROOT', ${PIVILION_WEBROOT@Q});
EOF
    php_version=$(php -r 'echo PHP_MAJOR_VERSION.".".PHP_MINOR_VERSION;')
    install -d -m 0755 "/etc/php/$php_version/apache2/conf.d"
    install -m 0644 "$SOURCE_DIR/etc/php/pivilion.ini" "/etc/php/$php_version/apache2/conf.d/99-pivilion.ini"
}

migrate_legacy_console_greeter() {
    local tmp signatures=0
    systemctl disable --now pivilion-boot-greeter.service 2>/dev/null || true
    rm -f /etc/systemd/system/pivilion-boot-greeter.service /usr/local/lib/pivilion/boot-greeter.sh

    [ -f /etc/rc.local ] || return 0
    grep -q 'hostapd -B' /etc/rc.local && signatures=$((signatures + 1)) || true
    grep -q 'ifconfig br0' /etc/rc.local && signatures=$((signatures + 1)) || true
    grep -q 'iptables -t nat' /etc/rc.local && signatures=$((signatures + 1)) || true
    grep -q 'service dnsmasq start' /etc/rc.local && signatures=$((signatures + 1)) || true
    grep -q '/usr/local/lib/pivilion/mode.sh' /etc/rc.local && signatures=4 || true
    if [ "$signatures" -ge 4 ]; then
        cp -a /etc/rc.local "$BACKUP_DIR/legacy-rc.local"
        atomic_from_stdin /etc/rc.local 0755 <<'EOF'
#!/bin/sh -e
# Pivilion startup is managed by pivilion-mode.service.
exit 0
EOF
        log "Migrated legacy Pivilion rc.local; original saved in $BACKUP_DIR/legacy-rc.local"
    elif grep -q '/var/lib/tor/hidden_service/hostname.*home/pi/torname' /etc/rc.local; then
        cp -a /etc/rc.local "$BACKUP_DIR/legacy-rc.local"
        if grep -Fq '_IP=$(hostname -I)' /etc/rc.local && grep -Fq 'My IP address is' /etc/rc.local; then
            atomic_from_stdin /etc/rc.local 0755 <<'EOF'
#!/bin/sh -e
# Pivilion startup and the TTY banner are managed by systemd and agetty.
exit 0
EOF
        else
            tmp=$(mktemp)
            grep -v '/var/lib/tor/hidden_service/hostname.*home/pi/torname' /etc/rc.local > "$tmp"
            install -m 0755 "$tmp" /etc/rc.local
            rm -f "$tmp"
        fi
        log "Migrated legacy Pivilion onion rc.local; original saved in $BACKUP_DIR/legacy-rc.local"
    fi
}

configure_services() {
    local tmp
    log "Configuring services"
    tmp=$(mktemp); sed "s|/var/www/html/pivilion|$PIVILION_WEBROOT|g" "$SOURCE_DIR/etc/apache2/sites-available/000-default.conf" > "$tmp"; install -m 0644 "$tmp" /etc/apache2/sites-available/000-default.conf; rm -f "$tmp"
    tmp=$(mktemp); sed "s|/var/www/html/pivilion|$PIVILION_WEBROOT|g" "$SOURCE_DIR/etc/apache2/sites-available/000-upload.conf" > "$tmp"; install -m 0644 "$tmp" /etc/apache2/sites-available/000-upload.conf; rm -f "$tmp"
    install -m 0644 "$SOURCE_DIR/etc/apache2/ports.conf" /etc/apache2/ports.conf
    atomic_from_stdin /etc/apache2/conf-available/pivilion.conf <<EOF
<Directory "$PIVILION_WEBROOT">
    Options Indexes FollowSymLinks
    AllowOverride All
    Require all granted
</Directory>
EOF
    a2enmod rewrite; a2enconf pivilion; a2ensite 000-default.conf
    if ! grep -Fqx '%include /etc/tor/torrc.d/*.conf' /etc/tor/torrc; then
        tmp=$(mktemp); cp /etc/tor/torrc "$tmp"; printf '\n%%include /etc/tor/torrc.d/*.conf\n' >> "$tmp"; install -m 0644 "$tmp" /etc/tor/torrc; rm -f "$tmp"
    fi
    migrate_legacy_console_greeter
    systemctl daemon-reload
    systemctl enable apache2 pivilion-mode.service pivilion-login-banner.service
    systemctl enable tor@default.service 2>/dev/null || systemctl enable tor.service
    systemctl disable pivilion-dnsmasq.service pivilion-hostapd.service 2>/dev/null || true
    /usr/local/lib/pivilion/issue-banner.sh
    command -v agetty >/dev/null 2>&1 && agetty --reload >/dev/null 2>&1 || true
}

validate_install() {
    local failed=0
    log "Validating installation"
    bash -n /usr/local/lib/pivilion/*.sh /usr/local/bin/pivilion /usr/local/bin/pivilion-diagnose /usr/local/bin/hotspot /usr/local/bin/onion /usr/local/bin/pikey /usr/local/bin/generator /usr/local/bin/static /usr/local/bin/hotglue /usr/local/bin/htaccess || failed=1
    apache2ctl configtest || failed=1
    tor --verify-config -f /etc/tor/torrc || failed=1
    dnsmasq --test || failed=1
    php -l "$PIVILION_WEBROOT/gen.php" || failed=1
    systemd-analyze verify /etc/systemd/system/pivilion-*.service || failed=1
    grep -q '^My IP address is ' /etc/issue.d/90-pivilion.issue || failed=1
    grep -q '^@@@@@@@@@@@@@@@@@@@' /etc/issue.d/90-pivilion.issue || failed=1
    grep -q 'StandardOutput=null' /etc/systemd/system/pivilion-login-banner.service || failed=1
    if command -v shellcheck >/dev/null 2>&1; then shellcheck /usr/local/lib/pivilion/*.sh /usr/local/bin/pivilion* /usr/local/bin/hotspot /usr/local/bin/onion /usr/local/bin/pikey || failed=1; fi
    [ "$failed" -eq 0 ] || return "$PIVILION_E_INSTALL"
}

write_install_state() {
    atomic_from_stdin /var/lib/pivilion/install-state <<EOF
version=$INSTALL_VERSION
installed_at=$(date --iso-8601=seconds)
user=$PIVILION_USER
webroot=$PIVILION_WEBROOT
backup=$BACKUP_DIR
EOF
}

check_install() {
    local failed=0 file
    for file in /etc/pivilion.defaults /var/lib/pivilion/install-state /etc/issue.d/90-pivilion.issue \
        /usr/local/lib/pivilion/common.sh /usr/local/lib/pivilion/mode.sh /usr/local/lib/pivilion/diagnose.sh \
        /usr/local/lib/pivilion/issue-banner.sh /etc/systemd/system/pivilion-mode.service \
        /etc/systemd/system/pivilion-login-banner.service; do
        if [ ! -e "$file" ]; then echo "Missing: $file" >&2; failed=1; fi
    done
    if [ "$failed" -eq 0 ]; then validate_install || failed=1; fi
    if [ "$failed" -eq 0 ]; then log "Installed files and service configuration are valid"; return 0; fi
    echo "Installation check failed. Run sudo ./install.sh --repair" >&2
    return "$PIVILION_E_INSTALL"
}

preflight
case "$ACTION" in
    dry-run)
        log "Dry run complete; installation would install packages, back up managed configuration, deploy files, validate, and enable services."
        exit 0 ;;
    check) check_install; exit $? ;;
esac

backup_managed_files
install_packages
deploy_files
configure_services
validate_install
write_install_state
systemctl is-active --quiet apache2 2>/dev/null && systemctl reload apache2 || true
TRANSACTION_ACTIVE=0
trap - ERR INT TERM

log "Pivilion $ACTION completed for $PIVILION_USER. Reboot to enter $(pivilion_current_mode) mode."