#!/usr/bin/env bash
# prereqs.sh — detect distro, install missing prerequisites

detect_distro() {
    if command -v pacman   &>/dev/null; then echo "arch";
    elif command -v apt-get &>/dev/null; then echo "debian";
    elif command -v dnf     &>/dev/null; then echo "rhel";
    elif command -v yum     &>/dev/null; then echo "rhel-yum";
    elif command -v zypper  &>/dev/null; then echo "suse";
    else echo "unknown";
    fi
}

install_pkg() {
    local pkg="$1"
    local distro
    distro="$(detect_distro)"
    case "$distro" in
        arch)      sudo pacman -Sy --noconfirm "$pkg" ;;
        debian)    sudo apt-get update -qq && sudo apt-get install -y "$pkg" ;;
        rhel)      sudo dnf install -y "$pkg" ;;
        rhel-yum)  sudo yum install -y "$pkg" ;;
        suse)      sudo zypper install -y "$pkg" ;;
        *)         die "Unsupported distro — please install $pkg manually." ;;
    esac
}

ensure_git() {
    if command -v git &>/dev/null; then
        success "git $(git --version | awk '{print $3}')"
        return
    fi
    warn "git not found."
    ask_yn _install "Install git now?" "y"
    if [[ "$_install" != "y" ]]; then die "git is required."; fi
    gum spin --spinner dot --spinner.foreground "$C_MAUVE" \
        --title "  Installing git..." --title.foreground "$C_SKY" \
        -- bash -c "$(declare -f install_pkg detect_distro); install_pkg git"
    command -v git &>/dev/null || die "git installation failed."
    success "git $(git --version | awk '{print $3}')"
}

ensure_container_runtime() {
    if command -v podman &>/dev/null; then
        CONTAINER_CMD="podman"
        success "podman $(podman --version | awk '{print $3}')"
        return
    fi
    if command -v docker &>/dev/null; then
        CONTAINER_CMD="docker"
        success "docker $(docker --version | awk '{print $3}' | tr -d ',')"
        return
    fi

    warn "No container runtime found."
    echo ""
    gum style --foreground "$C_SKY" --margin "0 4" \
        "podman  — recommended (rootless, no daemon)" \
        "docker  — alternative"
    echo ""

    ask_choice _runtime "Which would you like to install?" \
        "podman (recommended)" \
        "docker"

    local runtime_choice="$_runtime"
    case "$runtime_choice" in
        podman*) _install_podman; CONTAINER_CMD="podman" ;;
        docker*) _install_docker; CONTAINER_CMD="docker" ;;
    esac

    command -v "$CONTAINER_CMD" &>/dev/null \
        || die "$CONTAINER_CMD installation failed. Please install manually."
    success "$CONTAINER_CMD installed"
}

_install_podman() {
    local distro
    distro="$(detect_distro)"
    gum spin --spinner dot --spinner.foreground "$C_MAUVE" \
        --title "  Installing podman..." --title.foreground "$C_SKY" \
        -- bash -c "$(declare -f install_pkg detect_distro); install_pkg podman"
}

_install_docker() {
    local distro
    distro="$(detect_distro)"
    case "$distro" in
        arch)    install_pkg docker ;;
        debian)  install_pkg docker.io ;;
        rhel)    install_pkg docker ;;
        rhel-yum) install_pkg docker ;;
        suse)    install_pkg docker ;;
        *)       die "Unsupported distro — install docker manually." ;;
    esac
    sudo systemctl enable --now docker 2>/dev/null || true
    sudo usermod -aG docker "$USER" 2>/dev/null || true
    warn "Added $USER to docker group — log out and back in for it to take effect."
}

ensure_api_key() {
    if [[ -n "${ANTHROPIC_API_KEY:-}" ]]; then
        success "ANTHROPIC_API_KEY is set"
        return
    fi

    # Resolve config dir — CLAUDE_CONFIG_DIR overrides default ~/.claude
    local claude_dir="${CLAUDE_CONFIG_DIR:-$HOME/.claude}"

    local creds_file=""
    if   [[ -f "$claude_dir/.credentials.json" ]]; then creds_file="$claude_dir/.credentials.json"
    elif [[ -f "$HOME/.claude.json"             ]]; then creds_file="$HOME/.claude.json"
    elif [[ -f "$claude_dir/.claude.json"       ]]; then creds_file="$claude_dir/.claude.json"
    elif [[ -f "$HOME/.anthropic/.credentials.json" ]]; then creds_file="$HOME/.anthropic/.credentials.json"
    fi

    if [[ -n "$creds_file" ]]; then
        success "Anthropic credentials found ($creds_file)"
        return
    fi

    warn "ANTHROPIC_API_KEY is not set."
    echo ""
    gum style --foreground "$C_SKY" --margin "0 4" \
        "Claude Code needs an Anthropic API key to run inside the container." \
        "Get one at: https://console.anthropic.com/settings/api-keys"
    echo ""

    local key
    key=$(gum input \
        --password \
        --placeholder "sk-ant-..." \
        --prompt "  › " \
        --prompt.foreground "$C_MAUVE" \
        --cursor.foreground "$C_MAUVE" \
        --header "  Anthropic API key" \
        --header.foreground "$C_SKY" \
        --width 70) || true

    if [[ -z "$key" ]]; then
        warn "No API key entered — set ANTHROPIC_API_KEY before running ./start.sh"
        return
    fi

    export ANTHROPIC_API_KEY="$key"
    success "ANTHROPIC_API_KEY set for this session"

    ask_yn _save "Save to shell profile (~/.zshrc / ~/.bashrc)?" "y"
    if [[ "$_save" == "y" ]]; then
        local profile
        if [[ "$SHELL" == */zsh ]]; then
            profile="$HOME/.zshrc"
        else
            profile="$HOME/.bashrc"
        fi
        if grep -q "ANTHROPIC_API_KEY" "$profile" 2>/dev/null; then
            warn "ANTHROPIC_API_KEY already in $profile — not adding again."
        else
            printf '\nexport ANTHROPIC_API_KEY="%s"\n' "$key" >> "$profile"
            success "Saved to $profile"
        fi
    fi
}

check_prerequisites() {
    header "Prerequisites"
    ensure_git
    ensure_container_runtime
    ensure_api_key
}