#!/usr/bin/env bash
# Install dsync from https://git.ai.infran.ru/ilyukhin/dsync.git
#
# Usage:
#   ./install_dsync.sh            # install to ~/.local/bin (default)
#   ./install_dsync.sh --system   # install to /usr/local/bin (requires sudo)
#   ./install_dsync.sh -d DIR     # install to custom DIR
#   ./install_dsync.sh -f         # force overwrite if target exists
#   ./install_dsync.sh -h         # show help
set -euo pipefail

REPO_URL="https://git.ai.infran.ru/ilyukhin/dsync.git"
RAW_BASE="https://git.ai.infran.ru/ilyukhin/dsync/-/raw"  # raw URL pattern: $RAW_BASE/<branch>/dsync
DEFAULT_USER_DIR="$HOME/.local/bin"

DEST_DIR="$DEFAULT_USER_DIR"
FORCE=0

print_help() {
  cat <<EOF
Install dsync from ${REPO_URL}

Options:
  -s, --system        install into /usr/local/bin (system-wide; may use sudo)
  -d DIR, --dest DIR  install into DIR
  -f, --force         overwrite existing file without asking
  -h, --help          show this help
EOF
}

# parse options
while [[ $# -gt 0 ]]; do
  case "$1" in
    -s|--system)
      DEST_DIR="/usr/local/bin"
      shift
      ;;
    -d|--dest)
      if [[ -z "${2:-}" ]]; then
        echo "Error: missing argument for $1" >&2
        exit 2
      fi
      DEST_DIR="$2"
      shift 2
      ;;
    -f|--force)
      FORCE=1
      shift
      ;;
    -h|--help)
      print_help
      exit 0
      ;;
    --)
      shift
      break
      ;;
    -*)
      echo "Unknown option: $1" >&2
      print_help
      exit 2
      ;;
    *)
      break
      ;;
  esac
done

DEST_PATH="$DEST_DIR/dsync"

# create temporary dir and ensure cleanup
TMPDIR="$(mktemp -d)"
trap 'rm -rf "$TMPDIR"' EXIT

echo "Installing dsync to: $DEST_DIR"

# ensure target directory exists (create with sudo if system dir)
if [[ ! -d "$DEST_DIR" ]]; then
  echo "Target directory $DEST_DIR does not exist — attempting to create it..."
  if ! mkdir -p "$DEST_DIR" 2>/dev/null; then
    echo "No permission to create $DEST_DIR, trying with sudo..."
    if ! command -v sudo >/dev/null 2>&1; then
      echo "sudo not available — cannot create $DEST_DIR" >&2
      exit 1
    fi
    sudo mkdir -p "$DEST_DIR"
  fi
fi

FOUND=""

# 1) Try to clone repo with git (if git available)
if command -v git >/dev/null 2>&1; then
  echo "git found — attempting shallow clone..."
  if git clone --depth 1 "$REPO_URL" "$TMPDIR/repo" >/dev/null 2>&1; then
    echo "Repository cloned."
  else
    echo "Shallow clone failed, attempting normal clone (may show output)..."
    git clone --depth 1 "$REPO_URL" "$TMPDIR/repo" || true
  fi

  if [[ -d "$TMPDIR/repo" ]]; then
    FOUND="$(find "$TMPDIR/repo" -maxdepth 6 -type f -name dsync -print -quit || true)"
  fi
fi

# 2) If git did not find the file, try to download raw file via curl (main/master)
if [[ -z "$FOUND" ]]; then
  if command -v curl >/dev/null 2>&1; then
    for BR in main master; do
      RAW_URL="$RAW_BASE/$BR/dsync"
      echo "Trying to download raw file: $RAW_URL"
      if curl --fail -L --max-redirs 5 -o "$TMPDIR/dsync" "$RAW_URL"; then
        # check that downloaded file looks like text/script, not HTML error
        if file "$TMPDIR/dsync" | grep -qE 'text|python|ASCII'; then
          FOUND="$TMPDIR/dsync"
          break
        else
          echo "Downloaded file from $RAW_URL does not look like a script - skipping."
        fi
      else
        echo "Failed to download $RAW_URL (404 or error)."
      fi
    done
  else
    echo "curl not installed and git did not yield a dsync file — cannot download." >&2
    exit 1
  fi
fi

if [[ -z "$FOUND" ]]; then
  echo "Could not locate dsync in the repository and raw download failed."
  echo "Repository may be private. If it's private, ensure you have access (SSH keys or credentials)."
  exit 1
fi

echo "Found source file at: $FOUND"

# Warn if target exists
if [[ -e "$DEST_PATH" && "$FORCE" -ne 1 ]]; then
  echo "Error: $DEST_PATH already exists. Use --force to overwrite." >&2
  exit 1
fi

# copy into destination (use sudo if target dir is not writable)
if touch "$DEST_DIR/.write_test" >/dev/null 2>&1; then
  rm -f "$DEST_DIR/.write_test"
  cp -f "$FOUND" "$DEST_PATH"
  chmod +x "$DEST_PATH"
  echo "Installed: $DEST_PATH"
else
  echo "No write permission to $DEST_DIR — using sudo to copy and set executable bit."
  if ! command -v sudo >/dev/null 2>&1; then
    echo "sudo is not available — cannot write to $DEST_DIR" >&2
    exit 1
  fi
  sudo cp -f "$FOUND" "$DEST_PATH"
  sudo chmod +x "$DEST_PATH"
  echo "Installed (via sudo): $DEST_PATH"
fi

# quick PATH check
echo
echo "PATH check:"
if command -v dsync >/dev/null 2>&1; then
  echo "dsync is found: $(command -v dsync)"
else
  echo "dsync was installed to $DEST_PATH but is not found in current PATH."
  echo "Make sure $DEST_DIR is in your PATH (add to ~/.profile, ~/.bashrc or ~/.zshrc if needed):"
  echo "  export PATH=\"$DEST_DIR:\$PATH\""
  echo "Then run 'hash -r' (bash) or 'rehash' (zsh) or restart your shell."
fi

echo "Done."