#include "file_utils.h"
#include "http_client.h"
#include <cstdlib>
#include <cstring>
#include <curl/curl.h>
#include <fstream>
#include <iostream>
#include <sstream>
#include <string>

/**
 * @brief Print usage information
 */
void printUsage(const char *programName) {
  std::cout
      << "WizardMerge CLI Frontend - Intelligent Merge Conflict Resolution\n\n";
  std::cout << "Usage:\n";
  std::cout << "  " << programName
            << " [OPTIONS] merge --base <file> --ours <file> --theirs <file>\n";
  std::cout << "  " << programName
            << " [OPTIONS] pr-resolve --url <pr_url> [--token <token>]\n";
  std::cout << "  " << programName << " [OPTIONS] git-resolve [FILE]\n";
  std::cout << "  " << programName << " --help\n";
  std::cout << "  " << programName << " --version\n\n";
  std::cout << "Global Options:\n";
  std::cout << "  --backend <url>     Backend server URL (default: "
               "http://localhost:8080)\n";
  std::cout << "  -v, --verbose       Enable verbose output\n";
  std::cout << "  -q, --quiet         Suppress non-error output\n";
  std::cout << "  -h, --help          Show this help message\n";
  std::cout << "  --version           Show version information\n\n";
  std::cout << "Commands:\n";
  std::cout << "  merge               Perform three-way merge\n";
  std::cout << "    --base <file>     Base version file (required)\n";
  std::cout << "    --ours <file>     Our version file (required)\n";
  std::cout << "    --theirs <file>   Their version file (required)\n";
  std::cout << "    -o, --output <file>  Output file (default: stdout)\n";
  std::cout << "    --format <format>    Output format: text, json (default: "
               "text)\n\n";
  std::cout << "  pr-resolve          Resolve pull request conflicts\n";
  std::cout << "    --url <url>       Pull request URL (required)\n";
  std::cout << "    --token <token>   GitHub API token (optional, can use "
               "GITHUB_TOKEN env)\n";
  std::cout << "    --branch <name>   Create branch with resolved conflicts "
               "(optional)\n";
  std::cout << "    -o, --output <dir>  Output directory for resolved files "
               "(default: stdout)\n\n";
  std::cout << "  git-resolve         Resolve Git merge conflicts (not yet "
               "implemented)\n";
  std::cout << "    [FILE]            Specific file to resolve (optional)\n\n";
  std::cout << "Examples:\n";
  std::cout << "  " << programName
            << " merge --base base.txt --ours ours.txt --theirs theirs.txt\n";
  std::cout << "  " << programName
            << " merge --base base.txt --ours ours.txt --theirs theirs.txt -o "
               "result.txt\n";
  std::cout << "  " << programName
            << " pr-resolve --url https://github.com/owner/repo/pull/123\n";
  std::cout << "  " << programName
            << " pr-resolve --url https://github.com/owner/repo/pull/123 "
               "--token ghp_xxx\n";
  std::cout << "  " << programName
            << " --backend http://remote:8080 merge --base b.txt --ours o.txt "
               "--theirs t.txt\n\n";
}

/**
 * @brief Print version information
 */
void printVersion() {
  std::cout << "WizardMerge CLI Frontend v1.0.0\n";
  std::cout << "Part of the WizardMerge Intelligent Merge Conflict Resolution "
               "system\n";
}

/**
 * @brief Parse command-line arguments and execute merge
 */
int main(int argc, char *argv[]) {
  // Default configuration
  std::string backendUrl = "http://localhost:8080";
  bool verbose = false;
  bool quiet = false;
  std::string command;
  std::string baseFile, oursFile, theirsFile, outputFile;
  std::string format = "text";
  std::string prUrl, githubToken, branchName;

  // Check environment variable
  const char *envBackend = std::getenv("WIZARDMERGE_BACKEND");
  if (envBackend) {
    backendUrl = envBackend;
  }

  // Check for GitHub token in environment
  const char *envToken = std::getenv("GITHUB_TOKEN");
  if (envToken) {
    githubToken = envToken;
  }

  // Parse arguments
  for (int i = 1; i < argc; ++i) {
    std::string arg = argv[i];

    if (arg == "--help" || arg == "-h") {
      printUsage(argv[0]);
      return 0;
    } else if (arg == "--version") {
      printVersion();
      return 0;
    } else if (arg == "--backend") {
      if (i + 1 < argc) {
        backendUrl = argv[++i];
      } else {
        std::cerr << "Error: --backend requires an argument\n";
        return 2;
      }
    } else if (arg == "--verbose" || arg == "-v") {
      verbose = true;
    } else if (arg == "--quiet" || arg == "-q") {
      quiet = true;
    } else if (arg == "merge") {
      command = "merge";
    } else if (arg == "pr-resolve") {
      command = "pr-resolve";
    } else if (arg == "git-resolve") {
      command = "git-resolve";
    } else if (arg == "--url") {
      if (i + 1 < argc) {
        prUrl = argv[++i];
      } else {
        std::cerr << "Error: --url requires an argument\n";
        return 2;
      }
    } else if (arg == "--token") {
      if (i + 1 < argc) {
        githubToken = argv[++i];
      } else {
        std::cerr << "Error: --token requires an argument\n";
        return 2;
      }
    } else if (arg == "--branch") {
      if (i + 1 < argc) {
        branchName = argv[++i];
      } else {
        std::cerr << "Error: --branch requires an argument\n";
        return 2;
      }
    } else if (arg == "--base") {
      if (i + 1 < argc) {
        baseFile = argv[++i];
      } else {
        std::cerr << "Error: --base requires an argument\n";
        return 2;
      }
    } else if (arg == "--ours") {
      if (i + 1 < argc) {
        oursFile = argv[++i];
      } else {
        std::cerr << "Error: --ours requires an argument\n";
        return 2;
      }
    } else if (arg == "--theirs") {
      if (i + 1 < argc) {
        theirsFile = argv[++i];
      } else {
        std::cerr << "Error: --theirs requires an argument\n";
        return 2;
      }
    } else if (arg == "--output" || arg == "-o") {
      if (i + 1 < argc) {
        outputFile = argv[++i];
      } else {
        std::cerr << "Error: --output requires an argument\n";
        return 2;
      }
    } else if (arg == "--format") {
      if (i + 1 < argc) {
        format = argv[++i];
      } else {
        std::cerr << "Error: --format requires an argument\n";
        return 2;
      }
    }
  }

  // Check if command was provided
  if (command.empty()) {
    std::cerr << "Error: No command specified\n\n";
    printUsage(argv[0]);
    return 2;
  }

  // Execute command
  if (command == "merge") {
    // Validate required arguments
    if (baseFile.empty() || oursFile.empty() || theirsFile.empty()) {
      std::cerr << "Error: merge command requires --base, --ours, and --theirs "
                   "arguments\n";
      return 2;
    }

    // Check files exist
    if (!FileUtils::fileExists(baseFile)) {
      std::cerr << "Error: Base file not found: " << baseFile << "\n";
      return 4;
    }
    if (!FileUtils::fileExists(oursFile)) {
      std::cerr << "Error: Ours file not found: " << oursFile << "\n";
      return 4;
    }
    if (!FileUtils::fileExists(theirsFile)) {
      std::cerr << "Error: Theirs file not found: " << theirsFile << "\n";
      return 4;
    }

    if (verbose) {
      std::cout << "Backend URL: " << backendUrl << "\n";
      std::cout << "Base file: " << baseFile << "\n";
      std::cout << "Ours file: " << oursFile << "\n";
      std::cout << "Theirs file: " << theirsFile << "\n";
    }

    // Read input files
    std::vector<std::string> baseLines, oursLines, theirsLines;
    if (!FileUtils::readLines(baseFile, baseLines)) {
      std::cerr << "Error: Failed to read base file\n";
      return 4;
    }
    if (!FileUtils::readLines(oursFile, oursLines)) {
      std::cerr << "Error: Failed to read ours file\n";
      return 4;
    }
    if (!FileUtils::readLines(theirsFile, theirsLines)) {
      std::cerr << "Error: Failed to read theirs file\n";
      return 4;
    }

    if (verbose) {
      std::cout << "Read " << baseLines.size() << " lines from base\n";
      std::cout << "Read " << oursLines.size() << " lines from ours\n";
      std::cout << "Read " << theirsLines.size() << " lines from theirs\n";
    }

    // Connect to backend and perform merge
    HttpClient client(backendUrl);

    if (!quiet) {
      std::cout << "Connecting to backend: " << backendUrl << "\n";
    }

    if (!client.checkBackend()) {
      std::cerr << "Error: Cannot connect to backend: " << client.getLastError()
                << "\n";
      std::cerr << "Make sure the backend server is running on " << backendUrl
                << "\n";
      return 3;
    }

    if (!quiet) {
      std::cout << "Performing three-way merge...\n";
    }

    std::vector<std::string> mergedLines;
    bool hasConflicts = false;

    if (!client.performMerge(baseLines, oursLines, theirsLines, mergedLines,
                             hasConflicts)) {
      std::cerr << "Error: Merge failed: " << client.getLastError() << "\n";
      return 1;
    }

    // Output results
    if (!quiet) {
      std::cout << "Merge completed. Has conflicts: "
                << (hasConflicts ? "Yes" : "No") << "\n";
      std::cout << "Result has " << mergedLines.size() << " lines\n";
    }

    // Write output
    if (outputFile.empty()) {
      // Write to stdout
      for (const auto &line : mergedLines) {
        std::cout << line << "\n";
      }
    } else {
      if (!FileUtils::writeLines(outputFile, mergedLines)) {
        std::cerr << "Error: Failed to write output file\n";
        return 4;
      }
      if (!quiet) {
        std::cout << "Output written to: " << outputFile << "\n";
      }
    }

    return hasConflicts ? 5 : 0;

  } else if (command == "pr-resolve") {
    // Validate required arguments
    if (prUrl.empty()) {
      std::cerr << "Error: pr-resolve command requires --url argument\n";
      return 2;
    }

    if (verbose) {
      std::cout << "Backend URL: " << backendUrl << "\n";
      std::cout << "Pull Request URL: " << prUrl << "\n";
      if (!githubToken.empty()) {
        std::cout << "Using GitHub token: " << githubToken.substr(0, 4)
                  << "...\n";
      }
    }

    // Connect to backend
    HttpClient client(backendUrl);

    if (!quiet) {
      std::cout << "Connecting to backend: " << backendUrl << "\n";
    }

    if (!client.checkBackend()) {
      std::cerr << "Error: Cannot connect to backend: " << client.getLastError()
                << "\n";
      std::cerr << "Make sure the backend server is running on " << backendUrl
                << "\n";
      return 3;
    }

    if (!quiet) {
      std::cout << "Resolving pull request conflicts...\n";
    }

    // Build JSON request for PR resolution
    std::ostringstream json;
    json << "{";
    json << "\"pr_url\":\"" << prUrl << "\"";
    if (!githubToken.empty()) {
      json << ",\"github_token\":\"" << githubToken << "\"";
    }
    if (!branchName.empty()) {
      json << ",\"create_branch\":true";
      json << ",\"branch_name\":\"" << branchName << "\"";
    }
    json << "}";

    // Perform HTTP POST to /api/pr/resolve
    std::string response;
    CURL *curl = curl_easy_init();
    if (!curl) {
      std::cerr << "Error: Failed to initialize CURL\n";
      return 3;
    }

    std::string url = backendUrl + "/api/pr/resolve";
    curl_easy_setopt(curl, CURLOPT_URL, url.c_str());
    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, json.str().c_str());

    auto WriteCallback = [](void *contents, size_t size, size_t nmemb,
                            void *userp) -> size_t {
      ((std::string *)userp)->append((char *)contents, size * nmemb);
      return size * nmemb;
    };

    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, +WriteCallback);
    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &response);

    struct curl_slist *headers = nullptr;
    headers = curl_slist_append(headers, "Content-Type: application/json");
    curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);

    CURLcode res = curl_easy_perform(curl);

    if (res != CURLE_OK) {
      std::cerr << "Error: Request failed: " << curl_easy_strerror(res) << "\n";
      curl_slist_free_all(headers);
      curl_easy_cleanup(curl);
      return 3;
    }

    curl_slist_free_all(headers);
    curl_easy_cleanup(curl);

    // Output response
    if (outputFile.empty()) {
      std::cout << "\n=== Pull Request Resolution Result ===\n";
      std::cout << response << "\n";
    } else {
      std::ofstream out(outputFile);
      if (!out) {
        std::cerr << "Error: Failed to write output file\n";
        return 4;
      }
      out << response;
      out.close();
      if (!quiet) {
        std::cout << "Result written to: " << outputFile << "\n";
      }
    }

    // Check if resolution was successful (simple check)
    if (response.find("\"success\":true") != std::string::npos) {
      if (!quiet) {
        std::cout << "\nPull request conflicts resolved successfully!\n";
      }
      return 0;
    } else {
      if (!quiet) {
        std::cerr
            << "\nFailed to resolve some conflicts. See output for details.\n";
      }
      return 1;
    }

  } else if (command == "git-resolve") {
    std::cerr << "Error: git-resolve command not yet implemented\n";
    return 1;
  } else {
    std::cerr << "Error: Unknown command: " << command << "\n";
    return 2;
  }

  return 0;
}