// This file is part of the 64k demo project.
// It implements the sequence compiler tool.
// Converts a text-based timeline description into C++ code.

#include <fstream>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>

struct EffectEntry {
  std::string class_name;
  std::string start;
  std::string end;
  std::string priority;
  std::string extra_args;
};

struct SequenceEntry {
  std::string start_time;
  std::string priority;
  std::vector<EffectEntry> effects;
};

std::string trim(const std::string &str) {
  size_t first = str.find_first_not_of(" 	");
  if (std::string::npos == first)
    return str;
  size_t last = str.find_last_not_of(" 	");
  return str.substr(first, (last - first + 1));
}

int main(int argc, char *argv[]) {
  if (argc != 3) {
    std::cerr << "Usage: " << argv[0] << " <input.seq> <output.cc>\n";
    std::cerr << "Example: " << argv[0] << " assets/demo.seq src/timeline.cc\n";
    return 1;
  }

  std::ifstream in_file(argv[1]);
  if (!in_file.is_open()) {
    std::cerr << "Error: Could not open input file " << argv[1] << "\n";
    return 1;
  }

  std::vector<SequenceEntry> sequences;
  SequenceEntry *current_seq = nullptr;

  std::string line;
  int line_num = 0;
  while (std::getline(in_file, line)) {
    line_num++;
    std::string trimmed = trim(line);
    if (trimmed.empty() || trimmed[0] == '#')
      continue;

    std::stringstream ss(trimmed);
    std::string command;
    ss >> command;

    if (command == "SEQUENCE") {
      std::string start, priority;
      if (!(ss >> start >> priority)) {
        std::cerr << "Error line " << line_num
                  << ": SEQUENCE requires <start> <priority>\n";
        return 1;
      }
      sequences.push_back({start, priority, {}});
      current_seq = &sequences.back();
    } else if (command == "EFFECT") {
      if (!current_seq) {
        std::cerr << "Error line " << line_num
                  << ": EFFECT found outside of SEQUENCE\n";
        return 1;
      }
      std::string class_name, start, end, priority;
      if (!(ss >> class_name >> start >> end >> priority)) {
        std::cerr << "Error line " << line_num
                  << ": EFFECT requires <Class> <start> <end> <priority>\n";
        return 1;
      }

      // Capture remaining args
      std::string extra_args;
      std::getline(ss, extra_args); // Read rest of line
      // Remove leading whitespace from getline if any (getline reads the space
      // after priority)
      extra_args = trim(extra_args);
      if (!extra_args.empty()) {
        extra_args = ", " + extra_args;
      }

      current_seq->effects.push_back(
          {class_name, start, end, priority, extra_args});
    } else {
      std::cerr << "Error line " << line_num << ": Unknown command '" << command
                << "'\n";
      return 1;
    }
  }

  std::ofstream out_file(argv[2]);
  if (!out_file.is_open()) {
    std::cerr << "Error: Could not open output file " << argv[2] << "\n";
    return 1;
  }

  out_file << "// Auto-generated by seq_compiler. Do not edit.\n";
  out_file << "#include \"gpu/demo_effects.h\"\n";
  out_file << "#include \"gpu/effect.h\"\n\n";
  out_file << "void LoadTimeline(MainSequence& main_seq, WGPUDevice device, "
              "WGPUQueue queue, WGPUTextureFormat format) {\n";

  for (const auto &seq : sequences) {
    out_file << "  {\n";
    out_file << "    auto seq = std::make_shared<Sequence>();\n";
    for (const auto &eff : seq.effects) {
      out_file << "    seq->add_effect(std::make_shared<" << eff.class_name
               << ">(device, queue, format" << eff.extra_args << "), "
               << eff.start << "f, " << eff.end << "f, " << eff.priority
               << ");\n";
    }
    out_file << "    main_seq.add_sequence(seq, " << seq.start_time << "f, "
             << seq.priority << ");\n";
    out_file << "  }\n";
  }

  out_file << "}\n";

  std::cout << "Successfully generated timeline with " << sequences.size()
            << " sequences.\n";

  return 0;
}