const { ScreepsAPI } = require("screeps-api");
const core = require("@actions/core");
const fs = require("fs");
const { glob } = require("glob");
const path = require("path");

/**
 * Replaces specific placeholder strings within the provided content with corresponding dynamic values.
 *
 * This function targets:
 * - {{gitHash}} -> GITHUB_SHA
 * - {{gitRef}} -> GITHUB_REF
 * - {{deployTime}} -> ISO timestamp
 * - {{hostname}} -> hostname
 *
 * @param {string} content
 * @param {string} hostname
 * @returns {string}
 */
function replacePlaceholders(content, hostname) {
  const deployTime = new Date().toISOString();
  const gitHash = process.env.GITHUB_SHA;
  const gitRef = process.env.GITHUB_REF;

  core.info("Replacing placeholders:");
  core.info(`  GITHUB_SHA: ${gitHash}`);
  core.info(`  GITHUB_REF: ${gitRef}`);
  core.info(`  deployTime: ${deployTime}`);
  core.info(`  hostname: ${hostname}`);

  return content
    .replace(/{{gitHash}}/g, gitHash)
    .replace(/{{gitRef}}/g, gitRef)
    .replace(/{{deployTime}}/g, deployTime)
    .replace(/{{hostname}}/g, hostname);
}

/**
 * Replaces placeholders in files matching a glob pattern.
 *
 * @param {string} pattern
 * @param {string} [prefix]
 * @param {string} hostname
 * @returns {Promise<string[]>}
 */
function readReplaceAndWriteFiles(pattern, prefix, hostname) {
  return new Promise((resolve, reject) => {
    const globPattern = prefix ? path.join(prefix, pattern) : pattern;

    glob(globPattern, async (err, files) => {
      if (err) {
        return reject(err);
      }

      let processPromises = [];

      files.forEach((file) => {
        core.info(`Replacing placeholders in file: ${file}`);
        let processPromise = fs.promises
          .readFile(file, "utf8")
          .then((content) => {
            content = replacePlaceholders(content, hostname);
            return fs.promises.writeFile(file, content);
          });

        processPromises.push(processPromise);
      });

      try {
        await Promise.all(processPromises);
        resolve(files);
      } catch (processError) {
        reject(processError);
      }
    });
  });
}

/**
 * Reads files matching a glob pattern into a dictionary.
 * @param {string} pattern
 * @param {string} prefix
 * @returns {Promise<Object>}
 */
function readFilesIntoDict(pattern, prefix) {
  const globPattern = prefix ? path.join(prefix, pattern) : pattern;

  return new Promise((resolve, reject) => {
    glob(globPattern, (err, files) => {
      if (err) {
        return reject(err);
      }

      let fileDict = {};
      let readPromises = [];

      files.forEach((file) => {
        let readPromise = fs.promises.readFile(file, "utf8").then((content) => {
          let key = file;
          if (prefix && file.startsWith(prefix)) {
            key = key.slice(prefix.length);
          }
          key = path.basename(key, path.extname(key));
          fileDict[key] = content;
        });

        readPromises.push(readPromise);
      });

      Promise.all(readPromises)
        .then(() => resolve(fileDict))
        .catch(reject);
    });
  });
}

/**
 * Validates the provided authentication credentials.
 * @param {string} token
 * @param {string} username
 * @param {string} password
 * @returns {string|null}
 */
function validateAuthentication(token, username, password) {
  if (token) {
    if (username || password) {
      return "Token is defined along with username and/or password.";
    }
  } else {
    if (!username && !password) {
      return "Neither token nor password and username are defined.";
    }
    if (username && !password) {
      return "Username is defined but no password is provided.";
    }
    if (!username && password) {
      return "Password is defined but no username is provided.";
    }
  }
  return null;
}

/**
 * Posts code to Screeps server.
 */
function postCode() {
  const protocol = core.getInput("protocol") || "https";
  const hostname = core.getInput("hostname") || "screeps.com";
  const port = core.getInput("port") || "443";
  const path = core.getInput("path") || "/";

  const token = core.getInput("token") || undefined;
  const username = core.getInput("username") || undefined;
  const password = core.getInput("password") || undefined;
  const prefix = core.getInput("source-prefix");
  const pattern = core.getInput("pattern") || "*.js";
  const branch = core.getInput("branch") || "default";

  const gitReplace = core.getInput("git-replace") || null;

  const login_arguments = {
    token,
    username,
    password,
    protocol,
    hostname,
    port,
    path,
  };

  const errorMessage = validateAuthentication(token, username, password);
  if (errorMessage) {
    core.setFailed(errorMessage);
    return Promise.reject(new Error(errorMessage));
  }

  const replacePromise = gitReplace
    ? readReplaceAndWriteFiles(gitReplace, prefix, hostname)
    : Promise.resolve();

  return replacePromise
    .then(() => readFilesIntoDict(pattern, prefix))
    .then((files_to_push) => {
      core.info(
        `Uploading ${
          Object.keys(files_to_push).length
        } file(s) to branch '${branch}':`,
      );
      Object.keys(files_to_push).forEach((key) => {
        core.info(`  File: ${key}`);
      });

      core.info("Authentication arguments:");
      core.info(JSON.stringify(login_arguments, null, 2));

      const api = new ScreepsAPI(login_arguments);

      if (token) {
        return api.code.set(branch, files_to_push).then((response) => {
          core.info(JSON.stringify(response, null, 2));
          console.log(`Code set successfully to ${branch}`);
        });
      } else {
        core.info(`Logging in as user ${username}`);
        return api
          .auth(username, password, login_arguments)
          .then(() => api.code.set(branch, files_to_push))
          .then(() => {
            console.log(`Code set successfully to ${branch}`);
          });
      }
    });
}

postCode().catch((err) => {
  core.setFailed(err.message || err);
});