import { AUTH_CONFIG } from "~/config";

// Import email templates as raw strings - Vite will bundle these at build time
import loginLinkTemplate from "./login-link.html?raw";
import passwordResetTemplate from "./password-reset.html?raw";
import emailVerificationTemplate from "./email-verification.html?raw";
import providerLinkedTemplate from "./provider-linked.html?raw";
import newDeviceLoginTemplate from "./new-device-login.html?raw";
import passwordSetTemplate from "./password-set.html?raw";

/**
 * Convert expiry string to human-readable format
 * @param expiry - Expiry string like "15m", "1h", "7d"
 * @returns Human-readable string like "15 minutes", "1 hour", "7 days"
 */
export function expiryToHuman(expiry: string): string {
  const value = parseInt(expiry);
  if (expiry.endsWith("m")) {
    return value === 1 ? "1 minute" : `${value} minutes`;
  } else if (expiry.endsWith("h")) {
    return value === 1 ? "1 hour" : `${value} hours`;
  } else if (expiry.endsWith("d")) {
    return value === 1 ? "1 day" : `${value} days`;
  }
  return expiry;
}

/**
 * Replace placeholders in template with actual values
 * @param template - Template string with {{PLACEHOLDER}} markers
 * @param vars - Object with placeholder values
 * @returns Processed template string
 */
function processTemplate(
  template: string,
  vars: Record<string, string>
): string {
  let processed = template;
  for (const [key, value] of Object.entries(vars)) {
    const placeholder = `{{${key}}}`;
    processed = processed.replaceAll(placeholder, value);
  }
  return processed;
}

export interface LoginLinkEmailParams {
  email: string;
  loginUrl: string;
  loginCode: string;
}

/**
 * Generate login link email HTML
 */
export function generateLoginLinkEmail(params: LoginLinkEmailParams): string {
  const expiryTime = expiryToHuman(AUTH_CONFIG.EMAIL_LOGIN_LINK_EXPIRY);

  return processTemplate(loginLinkTemplate, {
    LOGIN_URL: params.loginUrl,
    LOGIN_CODE: params.loginCode,
    EXPIRY_TIME: expiryTime
  });
}

export interface PasswordResetEmailParams {
  resetUrl: string;
}

/**
 * Generate password reset email HTML
 */
export function generatePasswordResetEmail(
  params: PasswordResetEmailParams
): string {
  const expiryTime = "1 hour"; // Password reset is hardcoded to 1 hour

  return processTemplate(passwordResetTemplate, {
    RESET_URL: params.resetUrl,
    EXPIRY_TIME: expiryTime
  });
}

export interface EmailVerificationParams {
  verificationUrl: string;
}

/**
 * Generate email verification email HTML
 */
export function generateEmailVerificationEmail(
  params: EmailVerificationParams
): string {
  const expiryTime = expiryToHuman(AUTH_CONFIG.EMAIL_VERIFICATION_LINK_EXPIRY);

  return processTemplate(emailVerificationTemplate, {
    VERIFICATION_URL: params.verificationUrl,
    EXPIRY_TIME: expiryTime
  });
}

export interface ProviderLinkedEmailParams {
  providerName: string;
  providerEmail?: string;
  linkTime: string;
  deviceInfo: string;
}

/**
 * Generate provider linked notification email HTML
 */
export function generateProviderLinkedEmail(
  params: ProviderLinkedEmailParams
): string {
  return processTemplate(providerLinkedTemplate, {
    PROVIDER_NAME: params.providerName,
    PROVIDER_EMAIL: params.providerEmail || "N/A",
    LINK_TIME: params.linkTime,
    DEVICE_INFO: params.deviceInfo
  });
}

export interface NewDeviceLoginEmailParams {
  deviceInfo: string;
  loginTime: string;
  ipAddress: string;
  loginMethod: string;
  accountUrl: string;
}

/**
 * Generate new device login notification email HTML
 */
export function generateNewDeviceLoginEmail(
  params: NewDeviceLoginEmailParams
): string {
  return processTemplate(newDeviceLoginTemplate, {
    DEVICE_INFO: params.deviceInfo,
    LOGIN_TIME: params.loginTime,
    IP_ADDRESS: params.ipAddress,
    LOGIN_METHOD: params.loginMethod,
    ACCOUNT_URL: params.accountUrl
  });
}

export interface PasswordSetEmailParams {
  providerName: string;
  setTime: string;
  deviceInfo: string;
  ipAddress: string;
}

/**
 * Generate password set notification email HTML
 */
export function generatePasswordSetEmail(
  params: PasswordSetEmailParams
): string {
  return processTemplate(passwordSetTemplate, {
    PROVIDER_NAME: params.providerName,
    SET_TIME: params.setTime,
    DEVICE_INFO: params.deviceInfo,
    IP_ADDRESS: params.ipAddress
  });
}