// Copyright (c) 2019 Pantor. All rights reserved.

#ifndef INCLUDE_INJA_ENVIRONMENT_HPP_
#define INCLUDE_INJA_ENVIRONMENT_HPP_

#include <memory>
#include <fstream>
#include <sstream>
#include <string>

#include <nlohmann/json.hpp>

#include "config.hpp"
#include "function_storage.hpp"
#include "parser.hpp"
#include "polyfill.hpp"
#include "renderer.hpp"
#include "string_view.hpp"
#include "template.hpp"
#include "utils.hpp"


namespace inja {

using json = nlohmann::json;

/*!
 * \brief Class for changing the configuration.
 */
class Environment {
 public:
  Environment(): Environment("") { }

  explicit Environment(const std::string& global_path): m_input_path(global_path), m_output_path(global_path) {}

  Environment(const std::string& input_path, const std::string& output_path): m_input_path(input_path), m_output_path(output_path) {}

  /// Sets the opener and closer for template statements
  void set_statement(const std::string& open, const std::string& close) {
    m_lexer_config.statement_open = open;
    m_lexer_config.statement_close = close;
    m_lexer_config.update_open_chars();
  }

  /// Sets the opener for template line statements
  void set_line_statement(const std::string& open) {
    m_lexer_config.line_statement = open;
    m_lexer_config.update_open_chars();
  }

  /// Sets the opener and closer for template expressions
  void set_expression(const std::string& open, const std::string& close) {
    m_lexer_config.expression_open = open;
    m_lexer_config.expression_close = close;
    m_lexer_config.update_open_chars();
  }

  /// Sets the opener and closer for template comments
  void set_comment(const std::string& open, const std::string& close) {
    m_lexer_config.comment_open = open;
    m_lexer_config.comment_close = close;
    m_lexer_config.update_open_chars();
  }

  /// Sets whether to remove the first newline after a block
  void set_trim_blocks(bool trim_blocks) {
    m_lexer_config.trim_blocks = trim_blocks;
  }

  /// Sets whether to strip the spaces and tabs from the start of a line to a block
  void set_lstrip_blocks(bool lstrip_blocks) {
    m_lexer_config.lstrip_blocks = lstrip_blocks;
  }

  /// Sets the element notation syntax
  void set_element_notation(ElementNotation notation) {
    m_parser_config.notation = notation;
  }


  Template parse(nonstd::string_view input) {
    Parser parser(m_parser_config, m_lexer_config, m_included_templates);
    return parser.parse(input);
  }

  Template parse_template(const std::string& filename) {
    Parser parser(m_parser_config, m_lexer_config, m_included_templates);
    return parser.parse_template(m_input_path + static_cast<std::string>(filename));
  }

  std::string render(nonstd::string_view input, const json& data) {
    return render(parse(input), data);
  }

  std::string render(const Template& tmpl, const json& data) {
    std::stringstream os;
    render_to(os, tmpl, data);
    return os.str();
  }

  std::string render_file(const std::string& filename, const json& data) {
    return render(parse_template(filename), data);
  }

  std::string render_file_with_json_file(const std::string& filename, const std::string& filename_data) {
    const json data = load_json(filename_data);
    return render_file(filename, data);
  }

  void write(const std::string& filename, const json& data, const std::string& filename_out) {
    std::ofstream file(m_output_path + filename_out);
    file << render_file(filename, data);
    file.close();
  }

  void write(const Template& temp, const json& data, const std::string& filename_out) {
    std::ofstream file(m_output_path + filename_out);
    file << render(temp, data);
    file.close();
  }

  void write_with_json_file(const std::string& filename, const std::string& filename_data, const std::string& filename_out) {
    const json data = load_json(filename_data);
    write(filename, data, filename_out);
  }

  void write_with_json_file(const Template& temp, const std::string& filename_data, const std::string& filename_out) {
    const json data = load_json(filename_data);
    write(temp, data, filename_out);
  }

  std::ostream& render_to(std::ostream& os, const Template& tmpl, const json& data) {
    Renderer(m_included_templates, m_callbacks).render_to(os, tmpl, data);
    return os;
  }

  std::string load_file(const std::string& filename) {
    Parser parser(m_parser_config, m_lexer_config, m_included_templates);
    return parser.load_file(m_input_path + filename);
  }

  json load_json(const std::string& filename) {
    std::ifstream file = open_file_or_throw(m_input_path + filename);
    json j;
    file >> j;
    return j;
  }

  void add_callback(const std::string& name, unsigned int numArgs, const CallbackFunction& callback) {
    m_callbacks.add_callback(name, numArgs, callback);
  }

  /** Includes a template with a given name into the environment.
   * Then, a template can be rendered in another template using the
   * include "<name>" syntax.
   */
  void include_template(const std::string& name, const Template& tmpl) {
    m_included_templates[name] = tmpl;
  }

 private:
  std::string m_input_path;
  std::string m_output_path;

  LexerConfig m_lexer_config;
  ParserConfig m_parser_config;

  FunctionStorage m_callbacks;
  TemplateStorage m_included_templates;
};

/*!
@brief render with default settings to a string
*/
inline std::string render(nonstd::string_view input, const json& data) {
  return Environment().render(input, data);
}

/*!
@brief render with default settings to the given output stream
*/
inline void render_to(std::ostream& os, nonstd::string_view input, const json& data) {
  Environment env;
  env.render_to(os, env.parse(input), data);
}

}

#endif  // INCLUDE_INJA_ENVIRONMENT_HPP_