#include "range.hpp"

#include <algorithm>
#include <iostream>
#include <iterator>
#include <vector>

template <typename R>
void print_range(R const& range);

template <typename R>
void test_range_size(R const& range);

int main() {
    using std::cout;
    using util::lang::range;
    using util::lang::indices;

    cout << "Basic usage: iterating over a range of numbers.\n";
    for (auto i : range(1, 5)) {
        cout << i << " ";
    }
    cout << "\n";

    cout << "Ranges can be “infinite”.\n";
    for (auto u : range(0u)) {
        if (u == 3u) {
            cout << "\n";
            break;
        }
        cout << u << " ";
    }

    cout << "Ranges can be non-numeric, as long as the type is incrementable and equality comparable.\n";
    print_range(range('a', 'd'));

    cout << "Ranges can be non-contiguous.\n";
    print_range(range(20u, 29u).step(2u));

    cout << "… and we can even step backwards.\n";
    for (auto i : range(100).step(-3)) {
        if (i < 90) {
            cout << "\n";
            break;
        }
        cout << i << " ";
    }
    cout << "\n";

    cout << "Container indices are a special case of ranges.\n";
    std::vector<int> x{1, 2, 3};
    print_range(indices(x));

    print_range(indices({"foo", "bar"}));

    cout << "Strings are containers, too.\n";
    print_range(indices("foobar").step(2));
    cout << "\n";

    // TODO: Test cases; do something smarter with them.
    print_range(range(6, 10));
    print_range(range(1, 8).step(2));
    print_range(range(8, 1).step(-2));
    print_range(range(8.0, 1.0).step(-2.0));
    cout << "\n";

    cout << "Mixed type inference:\n";
    print_range(range(0, sizeof "Hello"));
    cout << "Inferred as mangled type name "
        << typeid(typename std::iterator_traits<decltype(range(0, sizeof "Hello").begin())>::value_type).name()
        << " (expected: " << typeid(decltype(sizeof "Hello")).name() << ")\n";
    cout << "\n";

    test_range_size(range(1, 8).step(2));
    test_range_size(range(8.0, 1.0).step(-2.0));
    test_range_size(range(8, 1).step(-2));
    test_range_size(range(0.1, 0.11).step(2));
    test_range_size(range(-7, 1).step(7));
}

namespace util { namespace lang {

template <typename T>
std::ostream& operator <<(std::ostream& out, step_range_proxy<T> const& r) {
    return out << "range(" << *r.begin() << ", " << *r.end() << ")"
        << ".step(" << r.begin().step_ << ")";
}

template <typename T>
std::ostream& operator <<(std::ostream& out, range_proxy<T> const& r) {
    return out << "range(" << *r.begin() << ", " << *r.end() << ")";
}

}}

template <typename R>
void print_range(R const& range) {
    using T = typename std::iterator_traits<decltype(range.begin())>::value_type;
    std::cout << range << " = ";
    std::copy(range.begin(), range.end(), std::ostream_iterator<T>(std::cout, " "));
    std::cout << "\n";
}

template <typename R>
std::size_t manual_range_size(R const& range) {
    std::size_t size = 0;
    for (auto const& _ : range) ++size, (void) _;
    return size;
}

template <typename R>
void test_range_size(R const& range) {
    auto const real_size = manual_range_size(R{range});
    if (real_size == range.size()) {
        std::cout << range << ".size() = " << real_size << "\n";
    } else {
        std::cout << "ERROR: " << range << ".size() ≠ " << real_size
            << " (was " << range.size() << ")!\n";
    }
}