#!/bin/sh -e

# shellcheck disable=SC2034

RC='\033[0m'
RED='\033[31m'
YELLOW='\033[33m'
CYAN='\033[36m'
GREEN='\033[32m'

command_exists() {
for cmd in "$@"; do
    export PATH="$HOME/.local/share/flatpak/exports/bin:/var/lib/flatpak/exports/bin:$PATH"
    command -v "$cmd" >/dev/null 2>&1 || return 1
done
return 0
}

checkFlatpak() {
    if ! command_exists flatpak; then
        printf "%b\n" "${YELLOW}Installing Flatpak...${RC}"
        case "$PACKAGER" in
            pacman)
                "$ESCALATION_TOOL" "$PACKAGER" -S --needed --noconfirm flatpak
                ;;
            apk)
                "$ESCALATION_TOOL" "$PACKAGER" add flatpak
                ;;
            xbps-install)
                "$ESCALATION_TOOL" "$PACKAGER" -Sy flatpak
                ;;
            *)
                "$ESCALATION_TOOL" "$PACKAGER" install -y flatpak
                ;;
        esac
        printf "%b\n" "${YELLOW}Adding Flathub remote...${RC}"
        "$ESCALATION_TOOL" flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
        printf "%b\n" "${YELLOW}Applications installed by Flatpak may not appear on your desktop until the user session is restarted...${RC}"
    else
        if ! flatpak remotes | grep -q "flathub"; then
            printf "%b\n" "${YELLOW}Adding Flathub remote...${RC}"
            "$ESCALATION_TOOL" flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
        else
            printf "%b\n" "${CYAN}Flatpak is installed${RC}"
        fi
    fi
}

checkArch() {
    case "$(uname -m)" in
        x86_64 | amd64) ARCH="x86_64" ;;
        aarch64 | arm64) ARCH="aarch64" ;;
        *) printf "%b\n" "${RED}Unsupported architecture: $(uname -m)${RC}" && exit 1 ;;
    esac

    printf "%b\n" "${CYAN}System architecture: ${ARCH}${RC}"
}

checkAURHelper() {
    ## Check & Install AUR helper
    if [ "$PACKAGER" = "pacman" ]; then
        if [ -z "$AUR_HELPER_CHECKED" ]; then
            AUR_HELPERS="yay paru"
            for helper in ${AUR_HELPERS}; do
                if command_exists "${helper}"; then
                    AUR_HELPER=${helper}
                    printf "%b\n" "${CYAN}Using ${helper} as AUR helper${RC}"
                    AUR_HELPER_CHECKED=true
                    return 0
                fi
            done

            printf "%b\n" "${YELLOW}Installing yay as AUR helper...${RC}"
            "$ESCALATION_TOOL" "$PACKAGER" -S --needed --noconfirm base-devel git
            cd /opt && "$ESCALATION_TOOL" git clone https://aur.archlinux.org/yay-bin.git && "$ESCALATION_TOOL" chown -R "$USER":"$USER" ./yay-bin
            cd yay-bin && makepkg --noconfirm -si

            if command_exists yay; then
                AUR_HELPER="yay"
                AUR_HELPER_CHECKED=true
            else
                printf "%b\n" "${RED}Failed to install AUR helper.${RC}"
                exit 1
            fi
        fi
    fi
}

checkEscalationTool() {
    ## Check for escalation tools.
    if [ -z "$ESCALATION_TOOL_CHECKED" ]; then
        if [ "$(id -u)" = "0" ]; then
            ESCALATION_TOOL="eval"
            ESCALATION_TOOL_CHECKED=true
            printf "%b\n" "${CYAN}Running as root, no escalation needed${RC}"
            return 0
        fi

        ESCALATION_TOOLS='sudo doas'
        for tool in ${ESCALATION_TOOLS}; do
            if command_exists "${tool}"; then
                ESCALATION_TOOL=${tool}
                printf "%b\n" "${CYAN}Using ${tool} for privilege escalation${RC}"
                ESCALATION_TOOL_CHECKED=true
                return 0
            fi
        done

        printf "%b\n" "${RED}Can't find a supported escalation tool${RC}"
        exit 1
    fi
}

checkCommandRequirements() {
    ## Check for requirements.
    REQUIREMENTS=$1
    for req in ${REQUIREMENTS}; do
        if ! command_exists "${req}"; then
            printf "%b\n" "${RED}To run me, you need: ${REQUIREMENTS}${RC}"
            exit 1
        fi
    done
}

checkPackageManager() {
    ## Check Package Manager
    PACKAGEMANAGER=$1
    for pgm in ${PACKAGEMANAGER}; do
        if command_exists "${pgm}"; then
            PACKAGER=${pgm}
            printf "%b\n" "${CYAN}Using ${pgm} as package manager${RC}"
            break
        fi
    done

    ## Enable apk community packages
    if [ "$PACKAGER" = "apk" ] && grep -qE '^#.*community' /etc/apk/repositories; then
        "$ESCALATION_TOOL" sed -i '/community/s/^#//' /etc/apk/repositories
        "$ESCALATION_TOOL" "$PACKAGER" update
    fi

    if [ -z "$PACKAGER" ]; then
        printf "%b\n" "${RED}Can't find a supported package manager${RC}"
        exit 1
    fi
}

checkSuperUser() {
    ## Check SuperUser Group
    SUPERUSERGROUP='wheel sudo root'
    for sug in ${SUPERUSERGROUP}; do
        if groups | grep -q "${sug}"; then
            SUGROUP=${sug}
            printf "%b\n" "${CYAN}Super user group ${SUGROUP}${RC}"
            break
        fi
    done

    ## Check if member of the sudo group.
    if ! groups | grep -q "${SUGROUP}"; then
        printf "%b\n" "${RED}You need to be a member of the sudo group to run me!${RC}"
        exit 1
    fi
}

checkCurrentDirectoryWritable() {
    ## Check if the current directory is writable.
    GITPATH="$(dirname "$(realpath "$0")")"
    if [ ! -w "$GITPATH" ]; then
        printf "%b\n" "${RED}Can't write to $GITPATH${RC}"
        exit 1
    fi
}

checkDistro() {
    DTYPE="unknown"  # Default to unknown
    # Use /etc/os-release for modern distro identification
    if [ -f /etc/os-release ]; then
        . /etc/os-release
        DTYPE=$ID
    fi
}

checkEnv() {
    checkArch
    checkEscalationTool
    checkCommandRequirements "curl groups $ESCALATION_TOOL"
    checkPackageManager 'nala apt-get dnf pacman zypper apk xbps-install'
    checkCurrentDirectoryWritable
    checkSuperUser
    checkDistro
    checkAURHelper
}
