/**
 * Data model definitions and factory functions.
 *
 * All IDs are generated with a simple ULID-like timestamp + random suffix
 * to keep things sortable and collision-resistant without external deps.
 */

/**
 * Generate a unique ID (timestamp-based, sortable).
 * @returns {string}
 */
export function generateId() {
  const timestamp = Date.now().toString(36)
  const random = Math.random().toString(36).slice(2, 10)
  return `${timestamp}_${random}`
}

/**
 * @typedef {Object} CredentialEntry
 * @property {string} id - Unique identifier
 * @property {string} title - Display name (e.g. "GitHub", "Gmail")
 * @property {string} username - Login username or email
 * @property {string} encryptedPassword - AES-GCM encrypted password blob (JSON string)
 * @property {string} [url] - Website URL
 * @property {string} [notes] - Free-form notes
 * @property {string} [groupId] - Reference to a Group id (empty string = no group)
 * @property {string[]} [tags] - Free-form tags
 * @property {string} createdAt - ISO timestamp
 * @property {string} updatedAt - ISO timestamp
 */

/**
 * Create a new CredentialEntry.
 *
 * @param {Object} data
 * @param {string} data.title
 * @param {string} data.username
 * @param {string} data.encryptedPassword - Must already be encrypted
 * @param {string} [data.url]
 * @param {string} [data.notes]
 * @param {string} [data.groupId]
 * @param {string[]} [data.tags]
 * @returns {CredentialEntry}
 */
export function createEntry(data) {
  const now = new Date().toISOString()
  return {
    id: generateId(),
    title: data.title.trim(),
    username: data.username.trim(),
    encryptedPassword: data.encryptedPassword,
    url: data.url?.trim() || '',
    notes: data.notes?.trim() || '',
    groupId: data.groupId || '',
    tags: data.tags || [],
    createdAt: now,
    updatedAt: now,
  }
}

/**
 * Update an existing entry, preserving id and createdAt.
 *
 * @param {CredentialEntry} existing
 * @param {Object} data - Fields to update
 * @returns {CredentialEntry}
 */
export function updateEntry(existing, data) {
  return {
    ...existing,
    title: data.title !== undefined ? data.title.trim() : existing.title,
    username: data.username !== undefined ? data.username.trim() : existing.username,
    encryptedPassword: data.encryptedPassword !== undefined ? data.encryptedPassword : existing.encryptedPassword,
    url: data.url !== undefined ? data.url.trim() : existing.url,
    notes: data.notes !== undefined ? data.notes.trim() : existing.notes,
    groupId: data.groupId !== undefined ? data.groupId : existing.groupId,
    tags: data.tags !== undefined ? data.tags : existing.tags,
    updatedAt: new Date().toISOString(),
  }
}

/**
 * @typedef {Object} Group
 * @property {string} id - Unique identifier
 * @property {string} name - Display name
 * @property {string} [color] - Hex color for UI accent
 * @property {string} createdAt - ISO timestamp
 */

const GROUP_COLORS = [
  '#6c63ff', '#e5484d', '#34d399', '#fbbf24', '#3b82f6',
  '#ec4899', '#8b5cf6', '#14b8a6', '#f97316', '#06b6d4',
]

/**
 * Create a new Group.
 *
 * @param {string} name
 * @param {string} [color]
 * @returns {Group}
 */
export function createGroup(name, color) {
  return {
    id: generateId(),
    name: name.trim(),
    color: color || GROUP_COLORS[Math.floor(Math.random() * GROUP_COLORS.length)],
    createdAt: new Date().toISOString(),
  }
}

/**
 * Validate a credential entry form submission.
 *
 * @param {Object} data
 * @returns {{ valid: boolean, errors: string[] }}
 */
export function validateEntry(data) {
  const errors = []
  if (!data.title || !data.title.trim()) errors.push('Title is required')
  if (!data.username || !data.username.trim()) errors.push('Username is required')
  if (!data.encryptedPassword) errors.push('Password is required')
  return { valid: errors.length === 0, errors }
}

/**
 * Validate a group name.
 *
 * @param {string} name
 * @returns {{ valid: boolean, errors: string[] }}
 */
export function validateGroup(name) {
  const errors = []
  if (!name || !name.trim()) errors.push('Group name is required')
  else if (name.trim().length > 50) errors.push('Group name must be 50 characters or less')
  return { valid: errors.length === 0, errors }
}