#!/bin/bash
# generator-hosts.sh
# Gestione hosts locali & disponibili/abilitati
# Usa come root (scrive /etc/hosts)

set -u

ROOTFOLD="/opt/hosts_config"
BKPFOLD="$ROOTFOLD/backups"
AVFOLD="$ROOTFOLD/hosts-available"
ENFOLD="$ROOTFOLD/hosts-enabled"
GEN_SCRIPT="$ROOTFOLD/generator-hosts.sh"
MAINFOLD="$ROOTFOLD/hosts-main"
ALIASFOLD="$ROOTFOLD/localhost-aliases"
FIRSTBACKUP="$BKPFOLD/firstbackup.bkp"
HOSTS="/etc/hosts"

mkdir -p "$BKPFOLD"
shopt -s nullglob

# Arrays (popolate dalla funzione refresh_arrays)
localhosts=()
en_files=()
av_files=()
ne_files=()
alias_files=()
alias_names=()
en_files_content=()
ne_files_content=()

refresh_arrays() {
    localhosts=()
    en_files=()
    av_files=()
    ne_files=()
    alias_files=()
    alias_names=()
    en_files_content=()
    ne_files_content=()

    # local aliases
    for f in "$ALIASFOLD"/*.lhost; do
        [ -f "$f" ] || continue
        alias_files+=("$(basename "$f" .lhost)")
        alias_names+=("$(sed -n '1p' "$f")")
    done

    # enabled hosts
    for f in "$ENFOLD"/*.conf; do
        [ -f "$f" ] || continue
        en_files+=("$(basename "$f" .conf)")
        en_files_content+=("$(sed -n '1,200p' "$f")")
    done

    # available hosts
    for f in "$AVFOLD"/*.conf; do
        [ -f "$f" ] || continue
        av_files+=("$(basename "$f" .conf)")
    done

    # disabled = available che non sono in enabled
    for f in "$AVFOLD"/*.conf; do
        [ -f "$f" ] || continue
        name="$(basename "$f" .conf)"
        if [ ! -f "$ENFOLD/$name.conf" ]; then
            ne_files+=("$name")
            ne_files_content+=("$(sed -n '1,200p' "$f")")
        fi
    done
}

_summary_line() {
    echo "$1" | sed -n '1p'
}

#### ACTIONS ####

list_hosts_all() {
    refresh_arrays
    echo "[ List of all hosts ]"
    echo ""
    echo "---- Enabled Hosts ----"
    if [ ${#en_files[@]} -eq 0 ]; then
        echo "  (none)"
    else
        for i in "${!en_files[@]}"; do
            name="${en_files[$i]}"
            content="${en_files_content[$i]:-}"
            summary="$(_summary_line "$content")"
            printf "  %d) %s: %s\n" "$i" "$name" "$summary"
        done
    fi

    echo ""
    echo "---- Disabled Hosts ----"
    if [ ${#ne_files[@]} -eq 0 ]; then
        echo "  (none)"
    else
        for i in "${!ne_files[@]}"; do
            name="${ne_files[$i]}"
            content="${ne_files_content[$i]:-}"
            summary="$(_summary_line "$content")"
            printf "  %d) %s: %s\n" "$i" "$name" "$summary"
        done
    fi
}

enable_host() {
    refresh_arrays
    if [ ${#ne_files[@]} -eq 0 ]; then
        echo "[ No disabled hosts available to enable ]"
        return
    fi

    echo "[ Disabled hosts available to enable ]"
    for i in "${!ne_files[@]}"; do
        printf "  %d) %s\n" "$i" "${ne_files[$i]}"
    done

    read -p "Insert the index to enable: " idx
    if ! [[ "$idx" =~ ^[0-9]+$ ]] || [ "$idx" -ge "${#ne_files[@]}" ]; then
        echo "[ Invalid index ]"
        return
    fi

    sel="${ne_files[$idx]}"
    src="$AVFOLD/$sel.conf"
    dst="$ENFOLD/$sel.conf"
    if [ -e "$dst" ]; then
        echo "[ Already enabled: $sel ]"
        return
    fi
    ln -s "$src" "$dst"
    echo "[ Enabled host: $sel ]"
    refresh_arrays
}

disable_host() {
    refresh_arrays
    if [ ${#en_files[@]} -eq 0 ]; then
        echo "[ No enabled hosts to disable ]"
        return
    fi

    echo "[ Enabled hosts ]"
    for i in "${!en_files[@]}"; do
        printf "  %d) %s\n" "$i" "${en_files[$i]}"
    done

    read -p "Insert the index to disable: " idx
    if ! [[ "$idx" =~ ^[0-9]+$ ]] || [ "$idx" -ge "${#en_files[@]}" ]; then
        echo "[ Invalid index ]"
        return
    fi

    sel="${en_files[$idx]}"
    target="$ENFOLD/$sel.conf"
    if [ ! -e "$target" ]; then
        echo "[ Expected link not found: $target ]"
        return
    fi
    unlink "$target"
    echo "[ Disabled host: $sel ]"
    refresh_arrays
}

list_local_alias() {
    refresh_arrays
    echo "[ Local aliases (index -> name) ]"
    for i in "${!alias_files[@]}"; do
        printf "  %d) %s (file: %s.lhost)\n" "$i" "${alias_names[$i]}" "${alias_files[$i]}"
    done
}

add_local_alias() {
    refresh_arrays
    read -p "Enter new local alias (e.g. grav.site): " newalias
    newalias="${newalias// /}"
    if [ -z "$newalias" ]; then
        echo "[ Alias cannot be empty ]"
        return
    fi

    next=1
    while [ -e "$ALIASFOLD/$next.lhost" ]; do
        ((next++))
    done

    echo "$newalias" > "$ALIASFOLD/$next.lhost"
    echo "[ Added alias '$newalias' as $next.lhost ]"
    refresh_arrays
}

remove_local_alias() {
    refresh_arrays
    list_local_alias
    read -p "Enter index of alias to remove: " idx
    if ! [[ "$idx" =~ ^[0-9]+$ ]]; then
        echo "[ Invalid index ]"
        return
    fi
    if [ "$idx" -eq 0 ]; then
        echo "[ Cannot remove 0.lhost (localhost) ]"
        return
    fi
    file="$ALIASFOLD/$idx.lhost"
    if [ ! -f "$file" ]; then
        echo "[ No such alias file: $file ]"
        return
    fi
    rm -f "$file"
    echo "[ Removed alias index $idx ]"
    refresh_arrays
}

show_main_config() {
    echo "---- main.conf ----"
    [ -f "$MAINFOLD/main.conf" ] && sed -n '1,200p' "$MAINFOLD/main.conf" || echo "(main.conf not found)"
    echo ""
    echo "---- endfile.conf ----"
    [ -f "$MAINFOLD/endfile.conf" ] && sed -n '1,200p' "$MAINFOLD/endfile.conf" || echo "(endfile.conf not found)"
}

# NEW: create a new host file in hosts-available (asks name, ip, number of domains)
create_host() {
    refresh_arrays

    read -p "Enter new host filename (no extension, e.g. mysite): " name
    name="${name// /}"   # remove spaces
    if [ -z "$name" ]; then
        echo "[ Name cannot be empty ]"
        return
    fi
    if [[ ! "$name" =~ ^[A-Za-z0-9._-]+$ ]]; then
        echo "[ Invalid name: use only letters, numbers, . _ - ]"
        return
    fi
    if [ -f "$AVFOLD/$name.conf" ] || [ -L "$ENFOLD/$name.conf" ] || [ -f "$ENFOLD/$name.conf" ]; then
        echo "[ A host with that name already exists (available or enabled) ]"
        return
    fi

    read -p "Enter IP address for this host (e.g. 192.168.1.10): " ip
    ip="${ip// /}"
    if [ -z "$ip" ]; then
        echo "[ IP cannot be empty ]"
        return
    fi

    # ask how many domains
    read -p "How many domains do you want to add? (0 for none): " domcount
    if ! [[ "$domcount" =~ ^[0-9]+$ ]]; then
        echo "[ Invalid number ]"
        return
    fi

    domains=""
    if [ "$domcount" -gt 0 ]; then
        for ((i=1;i<=domcount;i++)); do
            read -p "Domain #$i (e.g. example.com): " d
            d="${d// /}"
            if [ -z "$d" ]; then
                echo "[ Empty domain skipped ]"
                continue
            fi
            domains="${domains} $d"
        done
        domains="${domains## }"  # trim leading space
    fi

    # write file (single line: IP<TAB>domain1 domain2 ...)
    {
        if [ -z "$domains" ]; then
            printf "%s\t%s\n" "$ip" "$name"
        else
            printf "%s\t%s\n" "$ip" "$domains"
        fi
    } > "$AVFOLD/$name.conf"

    echo "[ Created $AVFOLD/$name.conf ]"
    # ask whether enable now
    read -p "Enable this host now? [y/N]: " yn
    case "$yn" in
        [Yy]* )
            ln -s "$AVFOLD/$name.conf" "$ENFOLD/$name.conf"
            echo "[ Enabled: $name ]"
        ;;
        *) echo "[ Not enabled ]" ;;
    esac

    refresh_arrays
}

# Helper to build host contents (stdout or file)
_build_hosts_file() {
    out="$1"
    if [ "$out" = "-" ]; then
	echo "# --- localhost generate ---#" 
        printf "127.0.0.1"
        refresh_arrays
        for a in "${alias_names[@]}"; do
            printf " %s" "$a"
        done
        printf "\n\n"
	echo "# --- main not dynamic part --- #"
        [ -f "$MAINFOLD/main.conf" ] && sed -n '1,200p' "$MAINFOLD/main.conf" && printf "\n"
        refresh_arrays
	echo "# --- dynamic hosts --- #"
        for en in "${en_files[@]}"; do
            [ -f "$ENFOLD/$en.conf" ] && sed -n '1,500p' "$ENFOLD/$en.conf" && printf "\n"
        done
	echo "# --- end part ---#"
        [ -f "$MAINFOLD/endfile.conf" ] && sed -n '1,200p' "$MAINFOLD/endfile.conf" && printf "\n"
    else
        tmp="$out"
        : > "$tmp"
	echo "# --- localhost generate ---#" >> $tmp
        printf "127.0.0.1" >> "$tmp"
        refresh_arrays
        for a in "${alias_names[@]}"; do
            printf " %s" "$a" >> "$tmp"
        done
        printf "\n\n" >> "$tmp"
	echo "# --- main not dynamic part --- #" >> $tmp
        [ -f "$MAINFOLD/main.conf" ] && sed -n '1,200p' "$MAINFOLD/main.conf" >> "$tmp" && printf "\n" >> "$tmp"
        refresh_arrays
	echo "# --- dynamic hosts --- #" >> $tmp
        for en in "${en_files[@]}"; do
            [ -f "$ENFOLD/$en.conf" ] && sed -n '1,500p' "$ENFOLD/$en.conf" >> "$tmp" && printf "\n" >> "$tmp"
        done

	echo "# --- end part ---#" >> $tmp
        [ -f "$MAINFOLD/endfile.conf" ] && sed -n '1,200p' "$MAINFOLD/endfile.conf" >> "$tmp" && printf "\n" >> "$tmp"
    fi
}

write_hosts() {
    refresh_arrays
    tmpfile="$(mktemp)"
    _build_hosts_file "$tmpfile"
    ts="$(date +%F_%H%M%S)"
    mkdir -p "$BKPFOLD"
    cp -a "$HOSTS" "$BKPFOLD/hosts.bkp.$ts" 2>/dev/null || true
    mv "$tmpfile" "$HOSTS"
    chmod 644 "$HOSTS"
    echo "[ /etc/hosts written and backup saved as $BKPFOLD/hosts.bkp.$ts ]"
}

regenerate_hosts() {
    write_hosts
}

simulate_hosts() {
	echo "######  HOST SIMULATION ######"
	_build_hosts_file "-"
	echo "###### HOST OVER ######"
}

#### RUN ####
refresh_arrays

usage() {
    cat <<EOF
Usage: $0 <option>
  -l   List all hosts (enabled / disabled)
  -e   Enable host (choose from disabled list)
  -d   Disable host (choose from enabled list)
  -c   Create new host file (in hosts-available)
  -r   Regenerate /etc/hosts (writes file, makes backup)
  -s   Simulate /etc/hosts (print preview)
  -hl  List local hosts (aliases)
  -ha  Add local host (alias)
  -hr  Remove local host (alias) (cannot remove 0.lhost)
  -sw  Show main config (main.conf + endfile.conf)
EOF
}

case "${1:-}" in
    -l) list_hosts_all ;;
    -e) enable_host ;;
    -d) disable_host ;;
    -hl) list_local_alias ;;
    -ha) add_local_alias ;;
    -hr) remove_local_alias ;;
    -sw) show_main_config ;;
    -c) create_host ;;
    -r) regenerate_hosts ;;
    -s) simulate_hosts ;;
    *) usage ;;
esac