#!/usr/bin/env bash

set -euo pipefail

### ─────────────────────────────
### Step 1 — Collect system identity
### ─────────────────────────────
USER_NAME="$(whoami)"
HOSTNAME_NAME="$(hostname)"

echo "User: $USER_NAME"
echo "Hostname: $HOSTNAME_NAME"

TARGET_DIR="$HOME/Droidnix"
REPO_URL="https://gitea.data-pro.nu/henrov/nixos/src/branch/main/Droidnix"

### ─────────────────────────────
### Step 2 — Create target directory
### ─────────────────────────────
mkdir -p "$TARGET_DIR"

### ─────────────────────────────
### Step 3 — Download repository
### ─────────────────────────────
if command -v git >/dev/null 2>&1; then
    echo "Using git..."
    rm -rf "$TARGET_DIR"
    git clone "$REPO_URL" "$TARGET_DIR"

elif command -v wget >/dev/null 2>&1; then
    echo "Using wget..."
    TMP_ZIP="/tmp/droidnix.zip"
    wget -O "$TMP_ZIP" "$REPO_URL/archive/main.zip"
    unzip -o "$TMP_ZIP" -d /tmp
    rm -rf "$TARGET_DIR"
    mv /tmp/Droidnix-main "$TARGET_DIR"

elif command -v curl >/dev/null 2>&1; then
    echo "Using curl..."
    TMP_ZIP="/tmp/droidnix.zip"
    curl -L "$REPO_URL/archive/main.zip" -o "$TMP_ZIP"
    unzip -o "$TMP_ZIP" -d /tmp
    rm -rf "$TARGET_DIR"
    mv /tmp/Droidnix-main "$TARGET_DIR"

else
    echo "Error: git, wget, or curl required."
    exit 1
fi

### ─────────────────────────────
### Step 4 — Rename files/folders (deepest first)
### ─────────────────────────────
echo "Renaming paths..."

find "$TARGET_DIR" -depth -name '*traveldroid*' | while read -r path; do
    newpath="$(echo "$path" | sed "s/traveldroid/$HOSTNAME_NAME/g")"
    mv "$path" "$newpath"
done

find "$TARGET_DIR" -depth -name '*henrov*' | while read -r path; do
    newpath="$(echo "$path" | sed "s/henrov/$USER_NAME/g")"
    mv "$path" "$newpath"
done

### ─────────────────────────────
### Step 5 — Replace strings in file contents
### ─────────────────────────────
echo "Replacing file contents..."

# Helper: only text files
is_text() {
    file --mime "$1" | grep -q text
}

# 5.1 generated/*
if [ -d "$TARGET_DIR/generated" ]; then
    find "$TARGET_DIR/generated" -type f | while read -r f; do
        is_text "$f" && sed -i "s/henrov/$USER_NAME/g" "$f"
    done
fi

README="$TARGET_DIR/README.org"

# 5.2 + 5.6 (org blocks only)
if [ -f "$README" ]; then
    awk -v user="$USER_NAME" -v host="$HOSTNAME_NAME" '
    BEGIN { inblock=0 }
    /^\*\* =/ { inblock=1 }
    /^\#\+END_SRC/ { inblock=0 }
    {
        if (inblock) {
            gsub(/henrov/, user)
            gsub(/traveldroid/, host)
        }
        print
    }' "$README" > "$README.tmp" && mv "$README.tmp" "$README"
fi

# 5.3 + 5.4 global replacements
find "$TARGET_DIR" -type f | while read -r f; do
    if is_text "$f"; then
        sed -i \
            -e "s|~/Repos/nixos/Droidnix|~/Droidnix|g" \
            -e "s/traveldroid/$HOSTNAME_NAME/g" \
            "$f"
    fi
done

### ─────────────────────────────
### Step 6 — Generate hardware config
### ─────────────────────────────
HOST_DIR="$TARGET_DIR/generated/hosts/$HOSTNAME_NAME"
mkdir -p "$HOST_DIR"

echo "Generating hardware configuration..."

sudo nixos-generate-config --show-hardware-config \
    > "$HOST_DIR/hardware-configuration.nix"

### ─────────────────────────────
### Step 7 — Inject into README.org
### ─────────────────────────────
if [ -f "$README" ]; then
    echo "Updating README.org..."

    awk -v host="$HOSTNAME_NAME" -v file="$HOST_DIR/hardware-configuration.nix" '
    BEGIN {
        target = "#+BEGIN_SRC nix :tangle generated/hosts/" host "/hardware-configuration.nix :noweb yes :mkdirp yes :eval never"
        inblock=0
    }
    $0 == target {
        print
        while ((getline line < file) > 0) print line
        inblock=1
        next
    }
    inblock && $0 == "#+END_SRC" {
        print
        inblock=0
        next
    }
    !inblock { print }
    ' "$README" > "$README.tmp" && mv "$README.tmp" "$README"
fi

### ─────────────────────────────
### Step 8 — Build and activate
### ─────────────────────────────
echo "Building NixOS configuration..."

cd "$TARGET_DIR"
sudo nixos-rebuild switch --flake ".#$HOSTNAME_NAME"

### ─────────────────────────────
### Step 9 — Inform user
### ─────────────────────────────
cat <<EOF

Installation complete. Please reboot your system.

After rebooting, any changes to your NixOS configuration must be made in

~/Droidnix/README.org

Before rebuilding, first tangle the org file using:

  emacs --batch --no-init-file ~/Droidnix/README.org \\
    --eval "(require 'org)" \\
    --eval "(require 'ob-tangle)" \\
    --eval "(find-file \\"README.org\\")" \\
    --eval "(with-temp-message \\"\\" (org-babel-tangle))" \\
    --eval "(with-temp-message \\"\\" (org-html-export-to-html))"

Then rebuild with:

  cd ~/Droidnix && sudo nixos-rebuild switch --flake .#$(hostname)

EOF