sure/app/models/goal.rb

class Goal < ApplicationRecord
  include AASM, Monetizable

  COLORS = Category::COLORS
  ICONS = Category.icon_codes

  validates :icon, inclusion: { in: ICONS, allow_nil: true }

  belongs_to :family
  has_many :goal_accounts, dependent: :destroy
  has_many :linked_accounts, through: :goal_accounts, source: :account
  has_many :goal_pledges, dependent: :destroy
  has_many :open_pledges,
           -> { where(status: "open").where("expires_at >= ?", Time.current) },
           class_name: "GoalPledge"

  validates :name, presence: true, length: { maximum: 255 }
  validates :target_amount, presence: true, numericality: { greater_than: 0 }
  validates :currency, presence: true
  validate :must_have_at_least_one_linked_account
  validate :linked_accounts_must_be_depository
  validate :linked_accounts_must_match_goal_currency
  validate :linked_accounts_must_belong_to_family
  validate :currency_locked_once_linked

  monetize :target_amount

  scope :alphabetically, -> { order(Arel.sql("LOWER(name) ASC")) }
  scope :active_first, lambda {
    order(Arel.sql("CASE state WHEN 'active' THEN 0 WHEN 'paused' THEN 1 WHEN 'completed' THEN 2 ELSE 3 END"))
  }

  def self.advisory_lock_key_for(family_id)
    Digest::SHA1.hexdigest("goals:family:#{family_id}").to_i(16) % (2**63)
  end

  aasm column: :state do
    state :active, initial: true
    state :paused
    state :completed
    state :archived

    event :pause do
      transitions from: :active, to: :paused
    end

    event :resume do
      transitions from: :paused, to: :active
    end

    event :complete do
      transitions from: [ :active, :paused ], to: :completed
    end

    event :archive do
      transitions from: [ :active, :paused, :completed ], to: :archived
    end

    event :unarchive do
      transitions from: :archived, to: :active
    end
  end

  # Balance is the live balance of every linked depository account.
  # v1: single linked account in practice. v1.1+: minus other goals' allocations
  # via the upcoming GoalBacking query.
  def current_balance
    @current_balance ||= linked_accounts.sum { |a| a.balance.to_d }
  end

  def current_balance_money
    @current_balance_money ||= Money.new(current_balance, currency)
  end

  def remaining_amount
    @remaining_amount ||= [ target_amount - current_balance, 0 ].max
  end

  def remaining_amount_money
    @remaining_amount_money ||= Money.new(remaining_amount, currency)
  end

  def progress_percent
    return @progress_percent if defined?(@progress_percent)

    @progress_percent = if completed?
      100
    elsif target_amount.to_d.zero?
      0
    else
      [ ((current_balance.to_d / target_amount.to_d) * 100).round, 100 ].min
    end
  end

  def months_remaining
    return nil unless target_date

    months = (target_date.year - Date.current.year) * 12 + (target_date.month - Date.current.month)
    [ months, 0 ].max
  end

  def monthly_target_amount
    return @monthly_target_amount if defined?(@monthly_target_amount)

    @monthly_target_amount = if target_date.nil?
      nil
    elsif months_remaining.zero?
      remaining_amount
    else
      (remaining_amount.to_d / months_remaining).ceil(2)
    end
  end

  # 90-day rolling monthly pace: net inflow into linked accounts divided by
  # three months. Transfers between linked accounts net to zero — both sides
  # land inside this account set. Transfers from outside (e.g. checking →
  # linked savings) net positive, which is the behaviour we want: the user
  # taps "I just transferred…", the transfer arrives, balance goes up,
  # pace goes up, status flips off "behind". Excludes user-flagged-excluded
  # entries. Entry amount sign convention in Sure: inflow is negative.
  def pace
    return @pace if defined?(@pace)

    @pace = if linked_accounts.empty?
      0
    else
      account_ids = linked_accounts.map(&:id)
      net = Entry
        .joins("INNER JOIN transactions ON transactions.id = entries.entryable_id AND entries.entryable_type = 'Transaction'")
        .where(account_id: account_ids, date: 90.days.ago.to_date..Date.current)
        .where(excluded: false)
        .sum(:amount)
      (-net.to_d / 3).round(2)
    end
  end

  def pace_money
    @pace_money ||= Money.new(pace, currency)
  end

  # Months of cash on hand at current pace (open-ended goals).
  def months_of_runway
    return nil if target_date.present?
    return nil if pace.zero? || pace.negative?

    (current_balance.to_d / pace.to_d).round(1)
  end

  def to_donut_segments_json
    filled = current_balance.to_d
    rem = remaining_amount.to_d

    if filled.zero? && rem.zero?
      return [ { color: "var(--budget-unallocated-fill)", amount: 1, id: "unused" } ]
    end

    segments = []
    segments << { color: color.presence || "var(--color-blue-500)", amount: filled, id: "saved" } if filled.positive?
    segments << { color: "var(--budget-unallocated-fill)", amount: rem, id: "unused" } if rem.positive?
    segments
  end

  # 90-day balance trajectory of linked accounts. Used by the projection chart
  # to render the saved-to-date line. Returns an empty series when the linked
  # account lacks ≥30 days of history.
  def projection_payload
    series_values = balance_series_values
    saved_series = series_values.map { |v| { date: v.date.to_s, value: v.value.amount.to_f } }

    earliest = series_values.first&.date || created_at.to_date

    {
      saved_series: saved_series,
      start_date: earliest.to_s,
      today: Date.current.to_s,
      target_date: target_date&.to_s,
      target_amount: target_amount.to_f,
      current_amount: current_balance.to_f,
      avg_monthly: pace.to_f,
      required_monthly: monthly_target_amount.to_f,
      currency: currency,
      status: status.to_s,
      pending_pledge_amount: open_pledges.sum(:amount).to_f
    }
  end

  def display_status
    return @display_status if defined?(@display_status)

    @display_status = if archived?
      :archived
    elsif paused?
      :paused
    elsif completed?
      :completed
    else
      status
    end
  end

  # :reached         → progress_percent >= 100
  # :on_track        → has target_date and pace >= required monthly
  # :behind          → has target_date and pace < required monthly
  # :no_target_date  → open-ended
  def status
    return @status if defined?(@status)

    @status = if progress_percent >= 100
      :reached
    elsif target_date.nil?
      :no_target_date
    elsif monthly_target_amount.to_d <= pace.to_d
      :on_track
    else
      :behind
    end
  end

  # Date of the most-recently-matched pledge's underlying entry. Used by the
  # show header to display "Last saved N days ago". Anchoring on the entry's
  # date keeps the readout stable under sync re-runs (which would bump
  # pledge#updated_at). Returns nil if no pledge has resolved yet.
  def last_matched_pledge_at
    return @last_matched_pledge_at if defined?(@last_matched_pledge_at)

    @last_matched_pledge_at = Entry
      .where(entryable_type: "Transaction")
      .joins("INNER JOIN goal_pledges ON goal_pledges.matched_transaction_id = entries.entryable_id")
      .where(goal_pledges: { goal_id: id, status: "matched" })
      .maximum(:date)
  end

  def last_matched_pledge_days_ago
    last = last_matched_pledge_at
    return nil if last.nil?

    (Date.current - last).to_i
  end

  # True when any linked account is wired to a live sync provider (Plaid,
  # SimpleFIN, or any AccountProvider — Brex, Enable Banking, IBKR, Kraken,
  # SnapTrade, Lunchflow). Drives the pledge-create copy: connected accounts
  # get the "I just transferred…" path; manual-only accounts get "I just
  # saved…" so users aren't told to wait for a sync that won't happen.
  def any_connected_account?
    linked_accounts.any? { |a| !a.manual? }
  end

  # "I just transferred" for bank-connected accounts, "I just saved" for manual-only.
  def pledge_action_label_key
    any_connected_account? ? "goals.show.pledge_just_transferred" : "goals.show.pledge_just_saved"
  end

  # Single source of truth for the projection-chart subtitle / chart-aria
  # description. Used to live inline in show.html.erb as a 17-line if/elsif
  # chain. Returns an `html_safe` string when it picks the `_html` variant.
  def projection_summary
    return @projection_summary if defined?(@projection_summary)

    @projection_summary =
      if completed? || progress_percent >= 100
        I18n.t("goals.show.projection.reached")
      elsif target_date.nil?
        I18n.t("goals.show.projection.no_target_date")
      elsif monthly_target_amount && pace.to_d < monthly_target_amount.to_d
        I18n.t("goals.show.projection.behind")
      elsif pace.positive?
        months = (remaining_amount.to_d / pace.to_d).ceil
        I18n.t(
          "goals.show.projection.on_track_html",
          date: (Date.current >> months.to_i).strftime("%b %Y")
        )
      else
        I18n.t("goals.show.projection.no_pace")
      end
  end

  # Monthly extra needed beyond the current pace to hit the target on time.
  # Clamps at zero — never asks the user to "make up" a deficit they're
  # already ahead of.
  def catch_up_delta_money
    return Money.new(0, currency) if monthly_target_amount.nil?

    delta = [ monthly_target_amount.to_d - pace.to_d, 0 ].max
    Money.new(delta, currency)
  end

  private
    def balance_series_values
      return [] if linked_accounts.empty?

      Balance::ChartSeriesBuilder.new(
        account_ids: linked_accounts.map(&:id),
        currency: currency,
        period: Period.last_90_days
      ).balance_series.values
    rescue StandardError => e
      # Degrade gracefully (chart drops to target-line-only) but surface
      # the failure — silent fallbacks here masked real Builder bugs.
      Rails.logger.error("Goal##{id} balance series failed: #{e.class}: #{e.message}")
      Sentry.capture_exception(e) if defined?(Sentry)
      []
    end

    def must_have_at_least_one_linked_account
      return unless goal_accounts.reject(&:marked_for_destruction?).empty?

      errors.add(:base, :at_least_one_linked_account_required)
    end

    def linked_accounts_must_be_depository
      offending = goal_accounts.reject(&:marked_for_destruction?).reject do |sga|
        sga.account&.depository?
      end
      return if offending.empty?

      errors.add(:linked_accounts, :must_be_depository)
    end

    def linked_accounts_must_match_goal_currency
      return if currency.blank?

      mismatched = goal_accounts.reject(&:marked_for_destruction?).reject do |sga|
        sga.account.nil? || sga.account.currency == currency
      end
      return if mismatched.empty?

      errors.add(:linked_accounts, :currency_mismatch)
    end

    def linked_accounts_must_belong_to_family
      return if family.nil?

      foreign = goal_accounts.reject(&:marked_for_destruction?).reject do |sga|
        sga.account.nil? || sga.account.family_id == family_id
      end
      return if foreign.empty?

      errors.add(:linked_accounts, :must_belong_to_family)
    end

    def currency_locked_once_linked
      return unless persisted? && currency_changed?
      return unless goal_accounts.where.not(id: nil).exists?

      errors.add(:currency, :locked_after_linked)
    end
end