'use strict';

const SMS_TEMPLATE_DEFS = [
  {
    key: 'accountCreated',
    label: 'ایجاد حساب کاربری',
    envKey: 'SMS_TEMPLATE_ACCOUNT_CREATED',
    slots: [
      { key: 'username', label: 'نام کاربری', defaultName: 'user' },
      { key: 'password', label: 'رمز عبور', defaultName: 'password' },
      { key: 'fullName', label: 'نام کاربر', defaultName: 'name' },
      { key: 'phoneNumber', label: 'شماره همراه', defaultName: 'mobile' }
    ]
  },
  {
    key: 'classRegistered',
    label: 'ثبت‌نام در کلاس',
    envKey: 'SMS_TEMPLATE_CLASS_REGISTERED',
    slots: [
      { key: 'className', label: 'نام کلاس', defaultName: 'className' },
      { key: 'courseName', label: 'نام دوره', defaultName: 'courseName' },
      { key: 'fullName', label: 'نام کارآموز', defaultName: 'fullName' },
      { key: 'phoneNumber', label: 'شماره همراه', defaultName: 'mobile' }
    ]
  },
  {
    key: 'classReminder',
    label: 'یادآوری کلاس',
    envKey: 'SMS_TEMPLATE_CLASS_REMINDER',
    slots: [
      { key: 'className', label: 'نام کلاس', defaultName: 'className' },
      { key: 'courseName', label: 'نام دوره', defaultName: 'courseName' },
      { key: 'time', label: 'ساعت', defaultName: 'time' },
      { key: 'place', label: 'مکان', defaultName: 'place' },
      { key: 'fullName', label: 'نام کاربر', defaultName: 'fullName' },
      { key: 'phoneNumber', label: 'شماره همراه', defaultName: 'mobile' }
    ]
  },
  {
    key: 'invoiceCreated',
    label: 'ایجاد صورتحساب',
    envKey: 'SMS_TEMPLATE_INVOICE_CREATED',
    slots: [
      { key: 'fullName', label: 'نام کارآموز', defaultName: 'FULLNAME' },
      { key: 'amount', label: 'مبلغ', defaultName: 'PAYMENT_PRICE' },
      { key: 'course', label: 'نام دوره', defaultName: 'COURSE' },
      { key: 'phoneNumber', label: 'شماره همراه', defaultName: 'MOBILE' }
    ]
  }
];

const SMS_TEMPLATE_KEYS = SMS_TEMPLATE_DEFS.map((def) => def.key);

const envFallbackFor = (def) => {
  if (!def?.envKey) return '';
  return String(process.env[def.envKey] || '').trim();
};

const sanitizeTemplateId = (value) => {
  if (value == null) return '';
  const digits = String(value).trim();
  if (!digits) return '';
  if (!/^\d{1,30}$/.test(digits)) return null;
  return digits;
};

const sanitizeVariableName = (value) => {
  if (value == null) return '';
  const name = String(value).trim().replace(/^#+|#+$/g, '').trim();
  if (!name) return '';
  // Check for dangerous injection or control chars
  if (/[\r\n\t\0<>"'`]/.test(name)) return null;
  if (name.length > 100) return null;
  return name;
};

const defaultVariablesList = (def) => {
  return (def?.slots || []).map((slot) => ({
    slot: slot.key,
    name: slot.defaultName
  }));
};

const emptyTemplateEntry = (def) => ({
  templateId: '',
  variables: defaultVariablesList(def)
});

const toVariableItem = (item, fallbackSlot = '') => {
  if (item == null) return null;
  if (typeof item === 'object') {
    const slot = String(item.slot || fallbackSlot || '').trim();
    if (!slot) return null;
    return {
      slot,
      name: String(item.name || '').trim()
    };
  }
  const slot = String(fallbackSlot || '').trim();
  if (!slot) return null;
  return {
    slot,
    name: String(item).trim()
  };
};

const normalizeVariablesInput = (rawVariables, def) => {
  if (rawVariables == null) {
    return def ? defaultVariablesList(def) : [];
  }

  if (Array.isArray(rawVariables)) {
    return rawVariables.map((item) => toVariableItem(item)).filter(Boolean);
  }

  if (typeof rawVariables === 'object') {
    return Object.entries(rawVariables)
      .map(([key, value]) => toVariableItem(value, key))
      .filter(Boolean);
  }

  return def ? defaultVariablesList(def) : [];
};

const normalizeStoredEntry = (raw, def) => {
  if (raw == null || raw === '') {
    return {
      templateId: '',
      variables: def ? defaultVariablesList(def) : []
    };
  }
  if (typeof raw === 'string' || typeof raw === 'number') {
    return {
      templateId: String(raw),
      variables: def ? defaultVariablesList(def) : []
    };
  }
  if (typeof raw !== 'object') {
    return {
      templateId: '',
      variables: def ? defaultVariablesList(def) : []
    };
  }

  const variables = Object.prototype.hasOwnProperty.call(raw, 'variables')
    ? normalizeVariablesInput(raw.variables, def)
    : (def ? defaultVariablesList(def) : []);

  return {
    templateId: raw.templateId != null ? String(raw.templateId) : '',
    variables
  };
};

const parseIncomingVariables = (rawVariables, def) => {
  if (rawVariables === undefined) return undefined;
  return normalizeVariablesInput(rawVariables, def);
};

const mergeTemplateEntry = (def, storedRaw, incomingRaw = null) => {
  const storedEntry = normalizeStoredEntry(storedRaw, def);
  let templateId = storedEntry.templateId || envFallbackFor(def);
  let variables = storedEntry.variables;

  if (incomingRaw) {
    if (incomingRaw.templateId !== undefined) {
      const sanitized = sanitizeTemplateId(incomingRaw.templateId);
      if (sanitized === null) {
        const error = new Error(`Invalid SMS template ID for ${def?.key || 'template'}`);
        error.code = 'INVALID_TEMPLATE_ID';
        error.field = def?.key;
        throw error;
      }
      templateId = sanitized;
    }

    if (incomingRaw.variables !== undefined) {
      const parsed = parseIncomingVariables(incomingRaw.variables, def) || [];
      for (const item of parsed) {
        const sanitized = sanitizeVariableName(item.name);
        if (item.name && sanitized === null) {
          const error = new Error(`Invalid SMS variable name "${item.name}"`);
          error.code = 'INVALID_VARIABLE_NAME';
          error.field = `${def?.key}.${item.slot}`;
          error.rawName = item.name;
          throw error;
        }
      }
      variables = parsed;
    }
  } else if (!storedEntry.templateId) {
    templateId = envFallbackFor(def);
  }

  return {
    templateId,
    variables: resolveVariablesList(def, variables)
  };
};

const resolveVariablesList = (def, storedVariables) => {
  if (!storedVariables) {
    return defaultVariablesList(def);
  }

  return normalizeVariablesInput(storedVariables, def)
    .map((item) => {
      const slot = String(item.slot || '').trim();
      if (!slot) return null;
      const slotDef = (def?.slots || []).find((s) => s.key === slot);
      const rawName = item.name !== undefined && String(item.name).trim() !== ''
        ? String(item.name).trim()
        : slotDef?.defaultName || '';
      const sanitized = sanitizeVariableName(rawName);
      return {
        slot,
        name: sanitized || slotDef?.defaultName || slot
      };
    })
    .filter(Boolean);
};

const buildSmsParameters = (variables, valuesBySlot = {}) => {
  return normalizeVariablesInput(variables, null)
    .map((item) => {
      const name = sanitizeVariableName(item?.name);
      if (!name) return null;
      const slot = item?.slot;
      const value = slot ? valuesBySlot?.[slot] : '';
      return {
        name,
        value: String(value ?? '')
      };
    })
    .filter(Boolean);
};

module.exports = {
  SMS_TEMPLATE_DEFS,
  SMS_TEMPLATE_KEYS,
  envFallbackFor,
  sanitizeTemplateId,
  sanitizeVariableName,
  defaultVariablesList,
  emptyTemplateEntry,
  normalizeStoredEntry,
  parseIncomingVariables,
  mergeTemplateEntry,
  resolveVariablesList,
  buildSmsParameters
};