#!/usr/bin/env bash
set -euo pipefail

ROOT="$(pwd)"
SRC_DIR="$ROOT/src"
PATCH_OUT="$ROOT/ubuntu-lts-gtkmm4.generated.patch"

COMPAT_HPP="$SRC_DIR/GtkCompat.hpp"

if [[ ! -d "$SRC_DIR" ]]; then
  echo "ERROR: src/ not found. Run from project root." >&2
  exit 1
fi

mapfile -t FILES_TO_PATCH < <(find "$SRC_DIR" -type f -name "*.cpp" | sort)

TMPDIR="$(mktemp -d)"
trap 'rm -rf "$TMPDIR"' EXIT

backup_key() { echo "$1" | sed 's|/|__|g'; }

echo "[1/6] Backups"
for f in "${FILES_TO_PATCH[@]}"; do
  [[ -f "$f" ]] || continue
  cp -a "$f" "$TMPDIR/$(backup_key "$f").orig"
done

if [[ -f "$COMPAT_HPP" ]]; then
  cp -a "$COMPAT_HPP" "$TMPDIR/GtkCompat.hpp.orig"
else
  : > "$TMPDIR/GtkCompat.hpp.orig"
fi

echo "[2/6] Writing $COMPAT_HPP (Qt macro-safe)"
cat > "$COMPAT_HPP" <<'EOF'
#pragma once

#if defined(_MSC_VER) || defined(__clang__) || defined(__GNUC__)
  #define GTKCOMPAT_HAS_PUSH_POP_MACRO 1
#else
  #define GTKCOMPAT_HAS_PUSH_POP_MACRO 0
#endif

#if GTKCOMPAT_HAS_PUSH_POP_MACRO
  #ifdef signals
    #pragma push_macro("signals")
    #undef signals
    #define GTKCOMPAT_RESTORE_signals 1
  #endif
  #ifdef slots
    #pragma push_macro("slots")
    #undef slots
    #define GTKCOMPAT_RESTORE_slots 1
  #endif
  #ifdef emit
    #pragma push_macro("emit")
    #undef emit
    #define GTKCOMPAT_RESTORE_emit 1
  #endif
  #ifdef foreach
    #pragma push_macro("foreach")
    #undef foreach
    #define GTKCOMPAT_RESTORE_foreach 1
  #endif
  #ifdef Q_FOREACH
    #pragma push_macro("Q_FOREACH")
    #undef Q_FOREACH
    #define GTKCOMPAT_RESTORE_Q_FOREACH 1
  #endif
#else
  #ifdef signals
    #undef signals
  #endif
  #ifdef slots
    #undef slots
  #endif
  #ifdef emit
    #undef emit
  #endif
  #ifdef foreach
    #undef foreach
  #endif
  #ifdef Q_FOREACH
    #undef Q_FOREACH
  #endif
#endif

#include <gtkmm.h>
#include <string>
#include <vector>
#include <functional>

namespace GtkCompat
{
    inline void for_each_child(Gtk::Widget& parent, const std::function<void(Gtk::Widget*)>& fn)
    {
        for (auto* child = parent.get_first_child(); child != nullptr; child = child->get_next_sibling())
            fn(child);
    }

    inline std::vector<Gtk::Widget*> children(Gtk::Widget& parent)
    {
        std::vector<Gtk::Widget*> out;
        for_each_child(parent, [&](Gtk::Widget* w){ out.push_back(w); });
        return out;
    }

    inline void listbox_clear(Gtk::ListBox& lb)
    {
        for (auto* child = lb.get_first_child(); child != nullptr; )
        {
            auto* next = child->get_next_sibling();
            lb.remove(*child);
            child = next;
        }
    }
}

inline bool operator==(const Glib::ustring& lhs, const std::string& rhs) { return lhs.raw() == rhs; }
inline bool operator==(const std::string& lhs, const Glib::ustring& rhs) { return lhs == rhs.raw(); }
inline bool operator!=(const Glib::ustring& lhs, const std::string& rhs) { return !(lhs == rhs); }
inline bool operator!=(const std::string& lhs, const Glib::ustring& rhs) { return !(lhs == rhs); }

#if GTKCOMPAT_HAS_PUSH_POP_MACRO
  #ifdef GTKCOMPAT_RESTORE_Q_FOREACH
    #pragma pop_macro("Q_FOREACH")
    #undef GTKCOMPAT_RESTORE_Q_FOREACH
  #endif
  #ifdef GTKCOMPAT_RESTORE_foreach
    #pragma pop_macro("foreach")
    #undef GTKCOMPAT_RESTORE_foreach
  #endif
  #ifdef GTKCOMPAT_RESTORE_emit
    #pragma pop_macro("emit")
    #undef GTKCOMPAT_RESTORE_emit
  #endif
  #ifdef GTKCOMPAT_RESTORE_slots
    #pragma pop_macro("slots")
    #undef GTKCOMPAT_RESTORE_slots
  #endif
  #ifdef GTKCOMPAT_RESTORE_signals
    #pragma pop_macro("signals")
    #undef GTKCOMPAT_RESTORE_signals
  #endif
#endif

#undef GTKCOMPAT_HAS_PUSH_POP_MACRO
EOF

echo "[3/6] Ensuring includes"
for f in "${FILES_TO_PATCH[@]}"; do
  [[ -f "$f" ]] || continue
  if ! grep -q '^[[:space:]]*#include[[:space:]]*"GtkCompat\.hpp"[[:space:]]*$' "$f"; then
    perl -0777 -i -pe '
      if (s/(#include\s+"[^"]+\.hpp"\s*\n)/$1#include "GtkCompat.hpp"\n/s) {
      } else {
        $_ = "#include \"GtkCompat.hpp\"\n" . $_;
      }
    ' "$f"
  fi
done

echo "[4/6] Fix ListBox::remove_all()"
perl -pi -e 's/\b([A-Za-z_][A-Za-z0-9_]*)\.remove_all\(\)\s*;/GtkCompat::listbox_clear($1);/g' "${FILES_TO_PATCH[@]}"

echo "[5/6] Fix get_children() vars and loops (supports auto, auto&, auto*, braced and single-line)"
for f in "${FILES_TO_PATCH[@]}"; do
  [[ -f "$f" ]] || continue

  perl -i -pe '
    s/\bauto\s+(\w+)\s*=\s*([A-Za-z_][A-Za-z0-9_:>\-\.\(\)\s]*)\s*\.get_children\s*\(\s*\)\s*;/
      auto $1 = GtkCompat::children($2);/gx
  ' "$f"

  perl -i -pe '
    s/\bauto\s+(\w+)\s*=\s*([A-Za-z_][A-Za-z0-9_:>\-\.\(\)\s]*)\s*->get_children\s*\(\s*\)\s*;/
      auto $1 = GtkCompat::children(*($2));/gx
  ' "$f"

  perl -0777 -i -pe '
    s/for\s*\(\s*auto\s+(\w+)\s*:\s*([^\)]+?)\.get_children\s*\(\s*\)\s*\)\s*\{/
      for (auto* $1 = ($2).get_first_child(); $1 != nullptr; $1 = $1->get_next_sibling()) {/gsx
  ' "$f"

  perl -0777 -i -pe '
    s/for\s*\(\s*auto\s*&\s*(\w+)\s*:\s*([^\)]+?)\.get_children\s*\(\s*\)\s*\)\s*\{/
      for (auto* $1 = ($2).get_first_child(); $1 != nullptr; $1 = $1->get_next_sibling()) {/gsx
  ' "$f"

  perl -0777 -i -pe '
    s/for\s*\(\s*auto\s*\*\s*(\w+)\s*:\s*([^\)]+?)\.get_children\s*\(\s*\)\s*\)\s*\{/
      for (auto* $1 = ($2).get_first_child(); $1 != nullptr; $1 = $1->get_next_sibling()) {/gsx
  ' "$f"

  perl -0777 -i -pe '
    s/for\s*\(\s*auto\s+(\w+)\s*:\s*([^\)]+?)\-\>get_children\s*\(\s*\)\s*\)\s*\{/
      for (auto* $1 = ($2)->get_first_child(); $1 != nullptr; $1 = $1->get_next_sibling()) {/gsx
  ' "$f"

  perl -0777 -i -pe '
    s/for\s*\(\s*auto\s*&\s*(\w+)\s*:\s*([^\)]+?)\-\>get_children\s*\(\s*\)\s*\)\s*\{/
      for (auto* $1 = ($2)->get_first_child(); $1 != nullptr; $1 = $1->get_next_sibling()) {/gsx
  ' "$f"

  perl -0777 -i -pe '
    s/for\s*\(\s*auto\s*\*\s*(\w+)\s*:\s*([^\)]+?)\-\>get_children\s*\(\s*\)\s*\)\s*\{/
      for (auto* $1 = ($2)->get_first_child(); $1 != nullptr; $1 = $1->get_next_sibling()) {/gsx
  ' "$f"

  perl -0777 -i -pe '
    s@for\s*\(\s*auto\s+(\w+)\s*:\s*([^\n;]+?)\.get_children\s*\(\s*\)\s*\)\s*\n(\s*)([^\n;][^\n]*;)@
$3for (auto* $1 = ($2).get_first_child(); $1 != nullptr; ) {\n$3    auto* next = $1->get_next_sibling();\n$3    $4\n$3    $1 = next;\n$3}@gsx
  ' "$f"

  perl -0777 -i -pe '
    s@for\s*\(\s*auto\s*&\s*(\w+)\s*:\s*([^\n;]+?)\.get_children\s*\(\s*\)\s*\)\s*\n(\s*)([^\n;][^\n]*;)@
$3for (auto* $1 = ($2).get_first_child(); $1 != nullptr; ) {\n$3    auto* next = $1->get_next_sibling();\n$3    $4\n$3    $1 = next;\n$3}@gsx
  ' "$f"

  perl -0777 -i -pe '
    s@for\s*\(\s*auto\s*\*\s*(\w+)\s*:\s*([^\n;]+?)\.get_children\s*\(\s*\)\s*\)\s*\n(\s*)([^\n;][^\n]*;)@
$3for (auto* $1 = ($2).get_first_child(); $1 != nullptr; ) {\n$3    auto* next = $1->get_next_sibling();\n$3    $4\n$3    $1 = next;\n$3}@gsx
  ' "$f"

  perl -0777 -i -pe '
    s@for\s*\(\s*auto\s+(\w+)\s*:\s*([^\n;]+?)\-\>get_children\s*\(\s*\)\s*\)\s*\n(\s*)([^\n;][^\n]*;)@
$3for (auto* $1 = ($2)->get_first_child(); $1 != nullptr; ) {\n$3    auto* next = $1->get_next_sibling();\n$3    $4\n$3    $1 = next;\n$3}@gsx
  ' "$f"

  perl -0777 -i -pe '
    s@for\s*\(\s*auto\s*&\s*(\w+)\s*:\s*([^\n;]+?)\-\>get_children\s*\(\s*\)\s*\)\s*\n(\s*)([^\n;][^\n]*;)@
$3for (auto* $1 = ($2)->get_first_child(); $1 != nullptr; ) {\n$3    auto* next = $1->get_next_sibling();\n$3    $4\n$3    $1 = next;\n$3}@gsx
  ' "$f"

  perl -0777 -i -pe '
    s@for\s*\(\s*auto\s*\*\s*(\w+)\s*:\s*([^\n;]+?)\-\>get_children\s*\(\s*\)\s*\)\s*\n(\s*)([^\n;][^\n]*;)@
$3for (auto* $1 = ($2)->get_first_child(); $1 != nullptr; ) {\n$3    auto* next = $1->get_next_sibling();\n$3    $4\n$3    $1 = next;\n$3}@gsx
  ' "$f"
done

echo "[6/6] Generate patch artifact: $PATCH_OUT"
{
  echo "--- a/src/GtkCompat.hpp"
  echo "+++ b/src/GtkCompat.hpp"
  diff -u "$TMPDIR/GtkCompat.hpp.orig" "$COMPAT_HPP" || true
  echo

  for f in "${FILES_TO_PATCH[@]}"; do
    [[ -f "$f" ]] || continue
    orig="$TMPDIR/$(backup_key "$f").orig"
    [[ -f "$orig" ]] || continue

    rel="${f#$ROOT/}"
    echo "--- a/$rel"
    echo "+++ b/$rel"
    diff -u "$orig" "$f" || true
    echo
  done
} > "$PATCH_OUT"

echo "DONE. Residual get_children() occurrences (should be 0):"
grep -R --line-number "get_children()" -n "$SRC_DIR" || true
echo
echo "Patch written to: $PATCH_OUT"