1 files changed, 139 insertions, 0 deletions
diff --git a/client/input.hpp b/client/input.hpp
new file mode 100644
index 0000000..077d5c7
--- /dev/null
+++ b/client/input.hpp
@@ -0,0 +1,139 @@
+#pragma once
+
+#include "error.hpp"
+
+#include <exception>
+#include <fstream>
+#include <functional>
+#include <iostream>
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace math::client::input {
+
+class Error : public client::Error {
+public:
+    explicit Error(const std::string& what)
+        : client::Error{"input error: " + what} {
+    }
+};
+
+class Reader {
+public:
+    using InputHandler = std::function<bool (const std::string&)>;
+
+    virtual ~Reader() = default;
+
+    virtual bool for_each_input(const InputHandler& process) const = 0;
+};
+
+using ReaderPtr = std::unique_ptr<input::Reader>;
+
+class FileReader : public Reader {
+public:
+    explicit FileReader(const std::string& path)
+        : m_path{path}
+    { }
+
+    bool for_each_input(const InputHandler& process) const override {
+        return enum_lines(process);
+    }
+
+private:
+    bool enum_lines(const InputHandler& process) const {
+        std::ifstream ifs;
+        ifs.exceptions(std::ifstream::badbit);
+
+        try {
+            ifs.open(m_path);
+            if (!ifs.is_open()) {
+                throw Error{"couldn't open file: " + m_path};
+            }
+
+            for (std::string line; std::getline(ifs, line);) {
+                if (!process(line)) {
+                    return false;
+                }
+            }
+        } catch (const std::exception& e) {
+            throw Error{e.what()};
+        }
+
+        return true;
+    }
+
+    const std::string m_path;
+};
+
+class MultiFileReader : public Reader {
+public:
+    explicit MultiFileReader(const std::vector<std::string>& paths)
+        : m_paths{paths}
+    { }
+
+    bool for_each_input(const InputHandler& process) const override {
+        for (const auto& path : m_paths) {
+            const FileReader reader{path};
+            if (!reader.for_each_input(process)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+private:
+    const std::vector<std::string> m_paths;
+};
+
+inline input::ReaderPtr make_file_reader(const std::string& path) {
+    return std::make_unique<input::FileReader>(path);
+}
+
+inline input::ReaderPtr make_file_reader(const std::vector<std::string>& paths) {
+    return std::make_unique<input::MultiFileReader>(paths);
+}
+
+class StringReader : public Reader {
+public:
+    explicit StringReader(const std::string& input)
+        : m_input{input}
+    { }
+
+    bool for_each_input(const InputHandler& process) const override {
+        return process(m_input);
+    }
+
+private:
+    const std::string m_input;
+};
+
+inline input::ReaderPtr make_string_reader(const std::string& input) {
+    return std::make_unique<input::StringReader>(input);
+}
+
+class ConsoleReader : public Reader {
+public:
+    ConsoleReader() = default;
+
+    bool for_each_input(const InputHandler& process) const override {
+        std::string line;
+        while (read_line(line)) {
+            if (!process(line)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+private:
+    static bool read_line(std::string& dest) {
+        return static_cast<bool>(std::getline(std::cin, dest));
+    }
+};
+
+inline input::ReaderPtr make_console_reader() {
+    return std::make_unique<input::ConsoleReader>();
+}
+
+}