#!/usr/bin/env bash
set -e

# Nomarchy TTY Installer
# Golden path: BTRFS + LUKS2 encryption
#
# This is a minimal, single-path installer designed for TTY-only environments.
# For a customized installation, manually set up your disk and use the generated
# flake configuration as a starting point.

# Load the hardware-detection database — resolved relative to this script so it
# works whether we're invoked from /etc/install.sh on the live ISO or straight
# from a checkout.
_NOMARCHY_INSTALL_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
# shellcheck source=hardware-db.sh
source "$_NOMARCHY_INSTALL_DIR/hardware-db.sh"

# Colors and styling
RED='\033[0;31m'
GREEN='\033[0;32m'
BLUE='\033[0;34m'
YELLOW='\033[1;33m'
CYAN='\033[0;36m'
NC='\033[0m' # No Color
BOLD='\033[1m'

# Installer state
NOMARCHY_REPO=""
NOMARCHY_REV=""
HOSTNAME=""
TARGET_DRIVE=""
USERNAME=""
LUKS_PASSWORD=""
USER_PASSWORD=""
TIMEZONE="UTC"
HARDWARE_MODULES=""
NOMARCHY_HW_OPTS=""
# "" = not yet answered; "true"/"false" set by configure_impermanence.
ENABLE_IMPERMANENCE=""

# CLI flags
DRY_RUN="false"
RESUME="false"

# Resumable answers — passwords are NEVER persisted; the user re-enters them.
STATE_FILE="/tmp/nomarchy-install.state.sh"

# ============================================================================
# CLI / PERSISTENCE
# ============================================================================

usage() {
    cat <<USAGE
Usage: install.sh [--dry-run] [--resume] [-h|--help]

  --dry-run   Generate the flake into a tmpdir and run \`nix flake check\`.
              Doesn't touch the disk, doesn't run nixos-install.
  --resume    Reuse answers from a previous interrupted run
              (saved at $STATE_FILE — passwords excluded).
  -h, --help  Print this message.
USAGE
}

parse_args() {
    while (( $# > 0 )); do
        case "$1" in
            --dry-run) DRY_RUN="true" ;;
            --resume)  RESUME="true" ;;
            -h|--help) usage; exit 0 ;;
            *) echo "Unknown argument: $1" >&2; usage >&2; exit 2 ;;
        esac
        shift
    done
}

# Persist non-secret answers so an interrupted install can pick up where it
# left off. Uses `declare -p` so each line is a self-contained `declare --`
# statement that `source` re-establishes verbatim.
save_state() {
    declare -p \
        TARGET_DRIVE USERNAME HOSTNAME TIMEZONE \
        ENABLE_IMPERMANENCE HARDWARE_MODULES NOMARCHY_HW_OPTS NOMARCHY_REV \
        > "$STATE_FILE"
}

load_state() {
    if [[ "$RESUME" == "true" ]] && [[ -f "$STATE_FILE" ]]; then
        # shellcheck disable=SC1090
        source "$STATE_FILE"
        info "Resumed from $STATE_FILE"
    fi
}

# ============================================================================
# UTILITY FUNCTIONS
# ============================================================================

# Helper to run commands via nix run
nrun() {
    local pkg="$1"
    shift
    nix run --extra-experimental-features "nix-command flakes" "nixpkgs#$pkg" -- "$@"
}

header() {
    clear
    nrun gum style \
        --foreground 212 --border-foreground 212 --border double \
        --align center --width 60 --margin "1 2" --padding "2 4" \
        "NOMARCHY INSTALLER" "NixOS with Omarchy flavor"
    echo ""
}

section() {
    echo ""
    nrun gum style --foreground 14 --bold "━━━ $1 ━━━"
    echo ""
}

success() {
    nrun gum style --foreground 10 "✓ $1"
}

error() {
    nrun gum style --foreground 9 "✗ $1"
}

info() {
    nrun gum style --foreground 12 "→ $1"
}

# ============================================================================
# STEP 1: ENVIRONMENT CHECK
# ============================================================================

check_environment() {
    section "Environment Check"

    # Check for root
    if [[ $EUID -ne 0 ]]; then
        error "This installer must be run as root (use sudo)"
        exit 1
    fi
    success "Running as root"

    # Confirm we booted via UEFI. The disko config lays out a GPT + ESP and
    # we install systemd-boot/grub-efi; on a BIOS-booted host that doesn't
    # work and would partial-install before failing.
    if [[ ! -d /sys/firmware/efi ]]; then
        error "This installer requires a UEFI system (no /sys/firmware/efi)."
        info  "Reboot in UEFI mode (disable CSM/legacy in firmware setup) and try again."
        exit 1
    fi
    success "UEFI boot detected"

    # Find Nomarchy repo
    if [[ -d "/etc/nomarchy" ]]; then
        NOMARCHY_REPO="/etc/nomarchy"
    elif [[ -d "$(dirname "$0")/.." ]] && [[ -f "$(dirname "$0")/../flake.nix" ]]; then
        NOMARCHY_REPO="$(realpath "$(dirname "$0")/..")"
    fi

    if [[ -z "$NOMARCHY_REPO" ]]; then
        error "Nomarchy repository not found"
        exit 1
    fi
    success "Found Nomarchy at $NOMARCHY_REPO"

    # Capture the exact commit we're installing from. The generated flake
    # pins `nomarchy.url` to this revision so the installed system can't
    # silently drift onto a newer (possibly breaking) main.
    if command -v git >/dev/null 2>&1 && [[ -d "$NOMARCHY_REPO/.git" ]]; then
        NOMARCHY_REV=$(git -C "$NOMARCHY_REPO" rev-parse HEAD 2>/dev/null || echo "")
    fi
    if [[ -n "$NOMARCHY_REV" ]]; then
        success "Pinning Nomarchy to $NOMARCHY_REV"
    else
        info "Could not determine Nomarchy revision; downstream flake will track main."
    fi

    # Check internet
    gum spin --spinner dot --title "Checking internet connection..." -- sleep 1
    while ! ping -c 1 -W 2 1.1.1.1 &>/dev/null; do
        error "No internet connection"
        local choice
        choice=$(gum choose "Open Network Manager (nmtui)" "Retry" "Exit")
        case "$choice" in
            *nmtui*) nmtui ;;
            *Exit*) exit 1 ;;
        esac
    done
    success "Internet connection verified"
}

# ============================================================================
# STEP 2: DISK SELECTION
# ============================================================================

select_disk() {
    section "Disk Selection"

    if [[ -n "$TARGET_DRIVE" ]]; then
        success "Resumed: $TARGET_DRIVE"
        return
    fi

    info "Available drives:"
    echo ""
    lsblk -d -n -p -o NAME,SIZE,MODEL | grep -v loop
    echo ""

    local drives
    drives=$(lsblk -d -n -p -o NAME,SIZE | grep -v loop)
    TARGET_DRIVE=$(echo "$drives" | gum choose --header "Select target drive" | awk '{print $1}')

    if [[ -z "$TARGET_DRIVE" ]]; then
        error "No drive selected"
        exit 1
    fi

    if [[ "$DRY_RUN" != "true" ]]; then
        echo ""
        gum style --foreground 9 --bold "⚠ WARNING: All data on $TARGET_DRIVE will be DESTROYED!"
        echo ""
        if ! gum confirm "Are you sure you want to use $TARGET_DRIVE?"; then
            error "Aborted"
            exit 1
        fi
    fi

    success "Selected: $TARGET_DRIVE"
    save_state
}

# ============================================================================
# STEP 3: LUKS PASSPHRASE
# ============================================================================

get_luks_passphrase() {
    if [[ "$DRY_RUN" == "true" ]]; then
        info "Dry run: skipping LUKS passphrase prompt."
        LUKS_PASSWORD="dryrun-not-used"
        return
    fi

    section "Disk Encryption"

    info "Your disk will be encrypted with LUKS2."
    info "Enter a strong passphrase (you'll need this at every boot)."
    echo ""

    local pass1 pass2
    while true; do
        pass1=$(gum input --password --placeholder "Enter LUKS passphrase")
        [[ -z "$pass1" ]] && continue

        pass2=$(gum input --password --placeholder "Confirm passphrase")

        if [[ "$pass1" == "$pass2" ]]; then
            LUKS_PASSWORD="$pass1"
            break
        else
            error "Passphrases do not match. Try again."
        fi
    done

    success "Encryption passphrase set"
}

# ============================================================================
# STEP 4: USER CONFIGURATION
# ============================================================================

configure_user() {
    section "User Configuration"

    if [[ -z "$USERNAME" ]]; then
        USERNAME=$(nrun gum input --placeholder "Enter username (lowercase, no spaces)")
        if [[ -z "$USERNAME" ]] || [[ ! "$USERNAME" =~ ^[a-z][a-z0-9_-]*$ ]]; then
            error "Invalid username"
            exit 1
        fi
    fi
    success "Username: $USERNAME"

    if [[ -z "$HOSTNAME" ]]; then
        HOSTNAME=$(nrun gum input --value "nomarchy" --placeholder "Hostname for this machine")
        if [[ -z "$HOSTNAME" ]] || [[ ! "$HOSTNAME" =~ ^[a-z0-9][a-z0-9-]*$ ]]; then
            error "Invalid hostname (use lowercase letters, digits, and hyphens only)"
            exit 1
        fi
    fi
    success "Hostname: $HOSTNAME"

    if [[ "$DRY_RUN" == "true" ]]; then
        info "Dry run: skipping user password prompt."
        USER_PASSWORD="dryrun-not-used"
        save_state
        return
    fi

    # User password (can be same as LUKS or different)
    info "Set a password for your user account"
    local pass1 pass2
    while true; do
        pass1=$(nrun gum input --password --placeholder "Enter user password")
        [[ -z "$pass1" ]] && continue

        pass2=$(nrun gum input --password --placeholder "Confirm user password")

        if [[ "$pass1" == "$pass2" ]]; then
            USER_PASSWORD="$pass1"
            break
        else
            error "Passwords do not match. Try again."
        fi
    done

    success "User password set"
    save_state
}

# ============================================================================
# STEP 5: TIMEZONE
# ============================================================================

select_timezone() {
    section "Timezone"

    if [[ -n "$TIMEZONE" ]] && [[ "$TIMEZONE" != "UTC" ]]; then
        success "Resumed: $TIMEZONE"
        return
    fi

    local timezones
    timezones=$(timedatectl list-timezones 2>/dev/null || echo "UTC")
    TIMEZONE=$(echo "$timezones" | gum filter --placeholder "Search timezone...")

    [[ -z "$TIMEZONE" ]] && TIMEZONE="UTC"
    success "Timezone: $TIMEZONE"
    save_state
}

# ============================================================================
# STEP 6: HARDWARE VENDOR
# ============================================================================

select_hardware() {
    section "Hardware Configuration"

    if [[ -n "$HARDWARE_MODULES" ]]; then
        success "Resumed hardware modules"
        return
    fi

    local dmi_vendor dmi_product detect_output
    dmi_vendor=$(cat /sys/class/dmi/id/sys_vendor 2>/dev/null || echo "Unknown")
    dmi_product=$(cat /sys/class/dmi/id/product_name 2>/dev/null || echo "Unknown")
    info "DMI: $dmi_vendor / $dmi_product"
    echo ""

    # Auto-detect CPU, GPU, chassis, and known model from hardware-db.sh.
    detect_output=$(nomarchy_detect_hw || true)

    echo "Auto-detected:"
    nomarchy_hw_summary <<< "$detect_output"
    echo ""

    # Collect modules + nomarchy options from the detector output.
    local modules=() hw_opts=()
    while IFS= read -r line; do
        case "$line" in
            "MODULE "*) modules+=("${line#MODULE }") ;;
            "OPT "*)    hw_opts+=("${line#OPT }") ;;
        esac
    done <<< "$detect_output"

    # Let the user accept, extend, or replace the detection.
    local choice
    choice=$(nrun gum choose --header "Hardware configuration" \
        "Accept detected modules" \
        "Add an extra nixos-hardware module" \
        "Pick from the manual list (override)")

    case "$choice" in
        "Add an extra nixos-hardware module")
            local extra
            extra=$(nrun gum input --placeholder "e.g. asus-zephyrus-ga401 (no 'nixos-hardware.' prefix)")
            [[ -n "$extra" ]] && modules+=("$extra")
            ;;
        "Pick from the manual list (override)")
            modules=()
            hw_opts=()
            _select_hardware_manual modules hw_opts
            ;;
    esac

    # De-duplicate while preserving order.
    local seen="" uniq_mods=() m
    for m in "${modules[@]}"; do
        if [[ ":$seen:" != *":$m:"* ]]; then
            uniq_mods+=("$m")
            seen="$seen:$m"
        fi
    done

    # Emit a list the heredoc in generate_flake_config splats into
    # hardware-selection.nix's imports. The heredoc already indents the first
    # line by 4 spaces — we add real newlines + 4 spaces (via $'\n    ') for
    # subsequent lines so every entry lines up.
    HARDWARE_MODULES=""
    for m in "${uniq_mods[@]}"; do
        [[ -z "$HARDWARE_MODULES" ]] || HARDWARE_MODULES+=$'\n    '
        HARDWARE_MODULES+="inputs.nixos-hardware.nixosModules.${m}"
    done

    # Same treatment for nomarchy.hardware.* toggles.
    NOMARCHY_HW_OPTS=""
    local o
    for o in "${hw_opts[@]}"; do
        # opt is e.g. `isFramework=true` → `nomarchy.hardware.isFramework = true;`
        local key="${o%%=*}" val="${o#*=}"
        NOMARCHY_HW_OPTS+="nomarchy.hardware.${key} = ${val};"$'\n  '
    done

    success "Hardware configuration set (${#uniq_mods[@]} module$([[ ${#uniq_mods[@]} -eq 1 ]] || echo s))"
    save_state
}

# Manual fallback menu, kept for odd hardware the DB doesn't recognise yet.
# Writes into the two arrays named by its arguments (bash 4.3+ nameref).
_select_hardware_manual() {
    local -n _mods_ref="$1"
    local -n _opts_ref="$2"

    local vendor
    vendor=$(nrun gum choose --header "Pick vendor" \
        "Framework" "Dell" "Lenovo" "Apple (T2 Mac)" "Microsoft Surface" "ASUS" "System76" "Other...")

    case "$vendor" in
        Framework)
            local model
            model=$(nrun gum choose \
                "framework-16-7040-amd" \
                "framework-13-amd-ai-300-series" \
                "framework-13-7040-amd" \
                "framework-13-13th-gen-intel" \
                "framework-13-12th-gen-intel" \
                "framework-13-11th-gen-intel")
            _mods_ref+=("$model")
            _opts_ref+=("isFramework=true")
            ;;
        Dell)
            local model
            model=$(nrun gum choose \
                "dell-xps-15-9500" "dell-xps-15-9510" "dell-xps-15-9520" \
                "dell-xps-13-9310" "dell-xps-13-9370" "dell-xps-13-9380" \
                "dell-precision-5530" "dell-latitude-7480")
            _mods_ref+=("$model")
            [[ "$model" == *xps* ]] && _opts_ref+=("isXPS=true")
            ;;
        Lenovo)
            local model
            model=$(nrun gum choose \
                "lenovo-thinkpad-x1-carbon-gen11" "lenovo-thinkpad-x1-carbon-gen10" \
                "lenovo-thinkpad-x1-carbon-gen9"  "lenovo-thinkpad-x1-extreme" \
                "lenovo-thinkpad-t14-amd-gen3"    "lenovo-thinkpad-t14-amd-gen2" \
                "lenovo-thinkpad-t480"            "lenovo-thinkpad-l13")
            _mods_ref+=("$model")
            ;;
        "Apple (T2 Mac)")
            _mods_ref+=("apple-t2")
            _opts_ref+=("isT2Mac=true")
            ;;
        "Microsoft Surface")
            local model
            model=$(nrun gum choose \
                "microsoft-surface-pro-9" "microsoft-surface-pro-8" "microsoft-surface-pro-7" \
                "microsoft-surface-laptop-5" "microsoft-surface-laptop-4" "microsoft-surface-laptop-3")
            _mods_ref+=("$model")
            ;;
        ASUS)
            local model
            model=$(nrun gum choose \
                "asus-zephyrus-ga403" "asus-zephyrus-ga402" "asus-zephyrus-ga401" \
                "asus-zephyrus-ga503" "asus-rog-strix-g513" "asus-zenbook-ux")
            _mods_ref+=("$model")
            ;;
        System76)
            _mods_ref+=("system76")
            ;;
        "Other...")
            local custom
            custom=$(nrun gum input --placeholder "e.g. asus-zephyrus-ga401 (no 'nixos-hardware.' prefix)")
            [[ -n "$custom" ]] && _mods_ref+=("$custom")
            ;;
    esac
}

# ============================================================================
# STEP 7: IMPERMANENCE (OPTIONAL)
# ============================================================================

configure_impermanence() {
    section "Impermanence (Optional)"

    if [[ "$RESUME" == "true" ]] && [[ "$ENABLE_IMPERMANENCE" != "" ]]; then
        success "Resumed: impermanence = $ENABLE_IMPERMANENCE"
        return
    fi

    info "Impermanence erases your root filesystem on every boot."
    info "Only explicitly persisted files survive reboots."
    info "This provides a clean, reproducible system."
    echo ""

    if gum confirm "Enable Impermanence?"; then
        ENABLE_IMPERMANENCE="true"
        success "Impermanence enabled"
    else
        info "Impermanence disabled (traditional persistent root)"
    fi
    save_state
}

# ============================================================================
# STEP 8: REVIEW & CONFIRM
# ============================================================================

review_configuration() {
    section "Review Configuration"

    echo "  Drive:         $TARGET_DRIVE (BTRFS + LUKS2)"
    echo "  Hostname:      $HOSTNAME"
    echo "  Username:      $USERNAME"
    echo "  Timezone:      $TIMEZONE"
    echo "  Impermanence:  $ENABLE_IMPERMANENCE"
    echo "  Nomarchy rev:  ${NOMARCHY_REV:-main (unpinned)}"
    echo ""

    if [[ "$DRY_RUN" == "true" ]]; then
        info "Dry run: skipping destructive confirmation."
        return
    fi

    nrun gum style --foreground 9 "This will DESTROY all data on $TARGET_DRIVE"
    echo ""

    if ! nrun gum confirm "Proceed with installation?"; then
        error "Aborted"
        exit 1
    fi
}

# ============================================================================
# STEP 9: EXECUTION
# ============================================================================

execute_installation() {
    if [[ "$DRY_RUN" == "true" ]]; then
        execute_dry_run
        return
    fi

    section "Installing Nomarchy"

    # 9.1 Partition with disko
    info "Partitioning disk..."
    local disko_file tmp_disko
    disko_file="$NOMARCHY_REPO/installer/disko-golden.nix"
    tmp_disko=$(mktemp --suffix=.nix)

    sed "s|@TARGET_DRIVE@|${TARGET_DRIVE}|g" "$disko_file" > "$tmp_disko"

    # Provide the LUKS passphrase via tmpfs so the secret never touches a
    # spinning disk. /dev/shm is tmpfs on the live ISO. We restrict perms
    # to root and shred the file (overwrite) on the way out, even though
    # it's already in RAM — defense in depth.
    local luks_key="/dev/shm/nomarchy-luks.key"
    install -m 600 /dev/null "$luks_key"
    printf '%s' "$LUKS_PASSWORD" > "$luks_key"
    disko --mode disko "$tmp_disko"
    shred -u "$luks_key" 2>/dev/null || rm -f "$luks_key"
    unset LUKS_PASSWORD
    success "Disk partitioned"

    # 9.2 Generate hardware config
    info "Generating hardware configuration..."
    mkdir -p /mnt/etc/nixos
    nixos-generate-config --root /mnt
    success "Hardware configuration generated"

    # 9.3 Generate flake configuration
    info "Creating system configuration..."
    generate_flake_config
    success "Configuration generated"

    # 9.4 Resolve inputs once, here, and lock them. First boot then consumes
    # the same flake.lock and doesn't re-resolve a newer upstream.
    info "Resolving flake inputs (this pins nomarchy, nixpkgs, etc.)..."
    (
        cd /mnt/etc/nixos
        nix --extra-experimental-features "nix-command flakes" flake lock >/dev/null
    )
    success "flake.lock written"

    # 9.5 Initialize git repo so `nix` treats /etc/nixos as a flake worktree.
    info "Initializing git repository..."
    (
        cd /mnt/etc/nixos
        nrun git git init -q
        nrun git git add .
        nrun git git config user.name "Nomarchy Installer"
        nrun git git config user.email "installer@nomarchy"
        nrun git git commit -qm "Initial Nomarchy configuration"
    )
    success "Git repository initialized"

    # 9.6 Handle impermanence
    if [[ "$ENABLE_IMPERMANENCE" == "true" ]]; then
        info "Setting up impermanence..."
        mkdir -p /mnt/persist/etc
        mv /mnt/etc/nixos /mnt/persist/etc/
        mkdir -p /mnt/etc
        ln -s /persist/etc/nixos /mnt/etc/nixos
        success "Impermanence configured"
    fi

    # 9.7 Install the NixOS system from the freshly-generated flake.
    info "Running nixos-install (this will take a while)..."
    nixos-install --flake "/mnt/etc/nixos#$HOSTNAME" --no-root-passwd
    success "NixOS installed"

    # 9.8 Activate Home Manager for $USERNAME inside the new system so the
    # user's first login already has Nomarchy's dotfiles. `home-manager
    # switch` must run as the target user with a real $HOME, so we use
    # `runuser` (sudo -u keeps the caller's HOME → files land in /root).
    info "Activating Home Manager for $USERNAME..."
    if nixos-enter --root /mnt -- bash -c "
        set -e
        install -d -o '$USERNAME' -g users -m 0755 '/home/$USERNAME'
        runuser -u '$USERNAME' -- env HOME='/home/$USERNAME' \
            nix --extra-experimental-features 'nix-command flakes' \
            run 'home-manager/release-25.11' -- switch \
            --flake '/etc/nixos#$USERNAME' --impure
    "; then
        success "Home Manager activated"
    else
        error "Home Manager activation failed (non-fatal)."
        info  "Run \`nomarchy-env-update\` after the first login to retry."
    fi

    # 9.9 Pre-flight: catch evaluation errors in the freshly-installed
    # configuration *now*, while we can still fix them with `vi`, instead of
    # at the user's first post-reboot rebuild.
    info "Verifying configuration evaluates (nixos-rebuild dry-build)..."
    if nixos-enter --root /mnt -- bash -c "
        nixos-rebuild dry-build --flake /etc/nixos#$HOSTNAME 2>&1 | tail -20
    "; then
        success "Configuration evaluates cleanly"
    else
        error "Pre-flight rebuild check failed."
        info  "The system is installed; fix /etc/nixos before rebooting if possible."
    fi

    success "Installation complete!"
    rm -f "$STATE_FILE"
}

# ----------------------------------------------------------------------------
# Dry run: generate the flake into a tmpdir and parse-check it. Doesn't
# touch the disk; useful while iterating on the installer or to validate a
# saved state file before actually committing to the install.
# ----------------------------------------------------------------------------
execute_dry_run() {
    section "Dry Run"

    local tmp
    tmp=$(mktemp -d -t nomarchy-dryrun.XXXXXX)
    info "Generating configuration in $tmp"

    # Mock /mnt so the existing generator writes into the tmpdir.
    local fake_root="$tmp/mnt"
    mkdir -p "$fake_root/etc/nixos"
    ln -snf "$fake_root" "$tmp/.mntlink"
    # generate_flake_config writes to /mnt/etc/nixos directly. We can't
    # easily re-target without a refactor — bind-mount instead so the
    # absolute paths in the function still resolve to our tmpdir.
    mount --bind "$fake_root" /mnt 2>/dev/null || true

    if [[ ! -d /mnt/etc/nixos ]]; then
        mkdir -p /mnt/etc/nixos
    fi

    # Stub hardware-configuration.nix — `nixos-generate-config` requires
    # actually-mounted target filesystems, so we provide a syntactically
    # valid placeholder for parse-checking only.
    cat > /mnt/etc/nixos/hardware-configuration.nix <<'EOF'
{ ... }: { boot.loader.systemd-boot.enable = true; fileSystems."/" = { device = "/dev/null"; fsType = "tmpfs"; }; }
EOF

    generate_flake_config

    info "Running \`nix-instantiate --parse\` on each generated file..."
    local f rc=0
    for f in flake.nix hardware-selection.nix system.nix home.nix; do
        if nix-instantiate --parse "/mnt/etc/nixos/$f" >/dev/null 2>&1; then
            success "  $f"
        else
            error  "  $f failed to parse"
            rc=1
        fi
    done

    info "Generated files:"
    ls -1 /mnt/etc/nixos/

    umount /mnt 2>/dev/null || true
    info "Output kept at $fake_root for inspection."

    if (( rc != 0 )); then
        error "Dry run reported parse errors."
        exit "$rc"
    fi
    success "Dry run OK — no disk touched."
}

# ============================================================================
# GENERATE FLAKE CONFIGURATION
# ============================================================================

generate_flake_config() {
    local impermanence_opt=""
    [[ "$ENABLE_IMPERMANENCE" == "true" ]] && impermanence_opt="nomarchy.system.impermanence.enable = true;"

    # Pin the upstream Nomarchy flake to the exact commit we're installing
    # from so the first post-reboot `nixos-rebuild` doesn't silently pull a
    # newer main. Fall back to tracking main if we couldn't resolve a SHA.
    local nomarchy_url
    if [[ -n "$NOMARCHY_REV" ]]; then
        nomarchy_url="github:bemagri/nomarchy/$NOMARCHY_REV"
    else
        nomarchy_url="github:bemagri/nomarchy"
    fi

    # flake.nix — the generator uses a non-quoted heredoc so $HOSTNAME,
    # $USERNAME, and $nomarchy_url expand inline.
    cat > /mnt/etc/nixos/flake.nix <<FLAKE_EOF
{
  description = "My Nomarchy Configuration";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
    nomarchy.url = "$nomarchy_url";
    nixos-hardware.url = "github:NixOS/nixos-hardware/master";
    home-manager = {
      url = "github:nix-community/home-manager/release-25.11";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  # Two-track Nomarchy workflow:
  #   * System changes  → sudo nixos-rebuild switch --flake /etc/nixos#$HOSTNAME
  #   * Dotfiles/themes → nomarchy-env-update (home-manager switch, no rebuild)
  #
  # Both consume the same \`pkgs\` below so overlays and allowUnfree stay in
  # sync across the two paths.
  outputs = { self, nixpkgs, nomarchy, home-manager, nixos-hardware, ... }@inputs:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs {
        inherit system;
        overlays = [ nomarchy.overlays.default ];
        config.allowUnfree = true;
      };
    in
    {
      nixosConfigurations.$HOSTNAME = nixpkgs.lib.nixosSystem {
        inherit pkgs;
        specialArgs = { inputs = nomarchy.inputs // inputs; };
        modules = [
          ./hardware-configuration.nix
          ./hardware-selection.nix
          nomarchy.nixosModules.system
          ./system.nix
        ];
      };

      # Standalone Home Manager — \`home-manager switch --flake /etc/nixos#$USERNAME\`
      # (which is what \`nomarchy-env-update\` runs). Kept separate from the
      # NixOS config so dotfile/theme iterations don't rebuild the system.
      homeConfigurations.$USERNAME = home-manager.lib.homeManagerConfiguration {
        inherit pkgs;
        extraSpecialArgs = { inputs = nomarchy.inputs // inputs; };
        modules = [
          nomarchy.nixosModules.home
          ./home.nix
          {
            home.username = "$USERNAME";
            home.homeDirectory = "/home/$USERNAME";
            home.stateVersion = "25.11";
          }
        ];
      };
    };
}
FLAKE_EOF

    # hardware-selection.nix
    cat > /mnt/etc/nixos/hardware-selection.nix << EOF
{ inputs, ... }:
{
  imports = [
    $HARDWARE_MODULES
  ];
  $NOMARCHY_HW_OPTS
}
EOF

    # system.nix — curated system-level options. Uncomment what you want and
    # run \`sudo nixos-rebuild switch --flake /etc/nixos#$HOSTNAME\` to apply.
    cat > /mnt/etc/nixos/system.nix << EOF
{ pkgs, ... }:
{
  networking.hostName = "$HOSTNAME";
  time.timeZone = "$TIMEZONE";

  $impermanence_opt

  # Compressed RAM swap. Near-free memory headroom on small machines and
  # harmless on big ones — kernel only uses it under pressure. Disable if
  # you've enabled disk swap or hibernation.
  zramSwap.enable = true;

  # System-wide packages. Most tools belong in home.nix instead — only put
  # things here that need to be available to all users or to root (e.g. CLI
  # tools used by sudo, system admin utilities).
  environment.systemPackages = with pkgs; [
    home-manager
    # --- CLI tools useful as root ---
    # wget
    # curl
    # rsync
    # htop
    # tree
    # tmux
  ];

  services.displayManager.autoLogin.enable = true;
  services.displayManager.autoLogin.user = "$USERNAME";

  users.users."$USERNAME" = {
    isNormalUser = true;
    initialPassword = "$USER_PASSWORD";
    extraGroups = [ "networkmanager" "wheel" "video" "audio" "render" ];
  };

  # --- Optional system services ---
  # Uncomment to enable. Some require extra groups on your user (see below).

  # Containers / virtualization
  # virtualisation.docker.enable = true;       # adds "docker" group
  # virtualisation.libvirtd.enable = true;     # adds "libvirtd" group — needed for virt-manager

  # Networking / sync
  # services.tailscale.enable = true;
  # services.syncthing = {
  #   enable = true;
  #   user = "$USERNAME";
  #   dataDir = "/home/$USERNAME";
  # };

  # Printing
  # services.printing.enable = true;

  # Flatpak (alternative app delivery)
  # services.flatpak.enable = true;
  # xdg.portal.enable = true;

  # Gaming (system-level — pairs with home.packages.steam)
  # programs.steam.enable = true;
  # programs.gamemode.enable = true;

  system.stateVersion = "25.11";
}
EOF

    # home.nix — curated app menu. Uncomment what you want and run
    # `nomarchy-env-update` to apply.
    cat > /mnt/etc/nixos/home.nix << 'EOF'
{ pkgs, ... }:
{
  # User-level packages (Home Manager).
  #
  # Nomarchy already ships a minimal desktop (firefox, thunar, mpv, imv, mako,
  # hyprlock, swww, wl-clipboard, grim, slurp, rofi-wayland, etc.). The list
  # below is a menu of extras — uncomment what you want and run
  # `nomarchy-env-update`.
  home.packages = with pkgs; [
    # --- Enabled by default ---
    btop                # Resource monitor (TUI)
    fastfetch           # System info at login
    chromium            # Secondary browser

    # --- Editors & dev ---
    # vscode
    # jetbrains.idea-community
    # neovide
    # zed-editor
    # lazygit
    # gh                  # GitHub CLI
    # docker-compose
    # postman
    # dbeaver-bin

    # --- Productivity ---
    # obsidian
    # libreoffice
    # thunderbird
    # zathura             # PDF viewer
    # zotero
    # xournalpp

    # --- Media ---
    # vlc
    # obs-studio
    # gimp
    # inkscape
    # kdenlive
    # spotify
    # audacity
    # yt-dlp

    # --- Comms ---
    # discord
    # telegram-desktop
    # signal-desktop
    # slack
    # zoom-us

    # --- Security ---
    # keepassxc
    # bitwarden-desktop
    # _1password-gui

    # --- Gaming ---
    # steam
    # lutris
    # heroic

    # --- CLI / utilities ---
    # ripgrep
    # fd
    # bat
    # eza
    # zoxide
    # fzf
    # httpie
    # tldr
  ];

  # Extra Home Manager modules go here (program configs, services, etc.).
}
EOF
}

# ============================================================================
# FINISH
# ============================================================================

finish() {
    header

    nrun gum style --foreground 10 --bold --align center "INSTALLATION COMPLETE!"
    echo ""
    echo "Nomarchy has been successfully installed."
    echo ""
    echo "Next steps:"
    echo "  1. Remove the installation media"
    echo "  2. Reboot your computer"
    echo "  3. Log in as: $USERNAME (host: $HOSTNAME)"
    echo "  4. Your configuration lives at /etc/nixos/"
    echo ""
    echo "Rebuild commands:"
    echo "  • System:   sudo nixos-rebuild switch --flake /etc/nixos#$HOSTNAME"
    echo "  • Dotfiles: nomarchy-env-update       (runs home-manager switch)"
    echo ""
    echo "Tip: run 'nomarchy-themes-prebuild' once to pre-cache every theme"
    echo "     variant. Theme switches after that are instant (no rebuild)."
    echo ""

    if nrun gum confirm "Reboot now?"; then
        reboot
    fi
}

# ============================================================================
# MAIN
# ============================================================================

main() {
    parse_args "$@"
    header
    load_state

    check_environment
    select_disk
    get_luks_passphrase
    configure_user
    select_timezone
    select_hardware
    configure_impermanence
    review_configuration
    execute_installation

    # Skip the reboot prompt on a dry run — nothing to reboot into.
    if [[ "$DRY_RUN" == "true" ]]; then
        info "Dry run finished."
        exit 0
    fi

    finish
}

main "$@"