#pragma once

#include <string>
#include <string_view>

#include <jvalidate/detail/anchor.h>
#include <jvalidate/detail/expect.h>
#include <jvalidate/detail/out.h>
#include <jvalidate/detail/pointer.h>
#include <jvalidate/uri.h>

namespace jvalidate::detail {
class Reference;

class RootReference {
private:
  friend class Reference;
  URI uri_;
  Anchor anchor_;

public:
  RootReference() = default;

  explicit RootReference(URI const & uri, Anchor const & anchor = {})
      : uri_(uri), anchor_(anchor) {}

  explicit RootReference(std::string_view ref) : RootReference(ref, discard_out) {}

  bool is_relative() const { return uri_.is_relative(); }
  URI const & uri() const { return uri_; }
  Anchor const & anchor() const { return anchor_; }

  friend std::ostream & operator<<(std::ostream & os, RootReference const & self) {
    return os << self.uri_ << '#' << self.anchor_;
  }
  auto operator<=>(RootReference const &) const = default;

private:
  RootReference(std::string_view ref, out<size_t> end) {
    end = std::string::npos;

    size_t end_of_uri = ref.find('#');
    uri_ = URI(ref.substr(0, end_of_uri));
    if (end_of_uri == std::string::npos) {
      return;
    }

    ref.remove_prefix(end_of_uri + 1);
    size_t const pointer_start = ref.find('/');
    anchor_ = Anchor(ref.substr(0, pointer_start));

    EXPECT_M(end || pointer_start == std::string::npos, "JSON-Pointer is illegal in this context");
    if (pointer_start != std::string::npos) {
      end = pointer_start + end_of_uri + 1;
    }
  }
};

class Reference {
private:
  RootReference root_;
  Pointer pointer_;

public:
  Reference() = default;

  explicit Reference(URI const & uri, Pointer const & pointer = {})
      : root_(uri), pointer_(pointer) {}

  explicit Reference(URI const & uri, Anchor const & anchor, Pointer const & pointer = {})
      : root_(uri, anchor), pointer_(pointer) {}

  explicit Reference(RootReference const & root, Pointer const & pointer = {})
      : root_(root), pointer_(pointer) {}

  explicit Reference(std::string_view ref) {
    size_t pointer_start = 0;
    root_ = RootReference(ref, pointer_start);
    if (pointer_start != std::string::npos) {
      pointer_ = ref.substr(pointer_start);
    }
  }

  URI const & uri() const { return root_.uri(); }
  Anchor const & anchor() const { return root_.anchor(); }
  Pointer const & pointer() const { return pointer_; }

  RootReference const & root() const { return root_; }
  Reference parent() const { return Reference(root_, pointer_.parent()); }

  /**
   * @brief Delegate function for {@see Pointer::operator/=}, but returning
   * this Reference.
   */
  Reference & operator/=(auto const & in) { return (pointer_ /= in, *this); }

  /**
   * @brief Delegate function for {@see Pointer::operator/}, but returning
   * a Reference.
   */
  Reference operator/(auto const & in) const { return Reference(*this) /= in; }

  friend std::ostream & operator<<(std::ostream & os, Reference const & self) {
    return os << self.root_ << self.pointer_;
  }
  auto operator<=>(Reference const &) const = default;
};
}