# frozen_string_literal: true

require "value_semantics/monkey_patched"

require_relative "tts_template"
require_relative "low_balance"

class CallAttempt
	def self.for(customer:, usage:, **kwargs)
		credit = [customer.minute_limit.to_d - usage, 0].max + customer.balance
		@kinds.each do |kind|
			ca = kind.call(
				customer: customer, usage: usage, credit: credit,
				**kwargs.merge(limits(customer, usage, credit, **kwargs))
			)
			return ca if ca
		end

		raise "No CallAttempt matched"
	end

	def self.limits(customer, usage, credit, rate:, **)
		return {} unless customer && usage && rate

		can_use = customer.minute_limit.to_d + customer.monthly_overage_limit
		{
			limit_remaining: ([can_use - usage, 0].max / rate).to_i,
			max_minutes: (credit / rate).to_i
		}
	end

	def self.register(&maybe_mk)
		@kinds ||= []
		@kinds << maybe_mk
	end

	value_semantics do
		customer_id String
		from String
		to(/\A\+\d+\Z/)
		call_id String
		direction Either(:inbound, :outbound)
		limit_remaining Integer
		max_minutes Integer
	end

	def to_render
		["#{direction}/connect", { locals: to_h }]
	end

	def to_s
		"Allowed(max_minutes: #{max_minutes}, limit_remaining: #{limit_remaining})"
	end

	def create_call(fwd, *args, &block)
		fwd.create_call(*args, &block)
	end

	def as_json(*)
		{
			from: from,
			to: to,
			customer_id: customer_id,
			limit_remaining: limit_remaining,
			max_minutes: max_minutes
		}
	end

	def to_json(*args)
		as_json.to_json(*args)
	end

	class Expired
		CallAttempt.register do |customer:, direction:, **|
			new(direction: direction) if customer.plan_name && !customer.active?
		end

		value_semantics do
			direction Either(:inbound, :outbound)
		end

		def view
			"#{direction}/expired"
		end

		def tts
			TTSTemplate.new(view).tts(self)
		end

		def to_render
			[view]
		end

		def create_call(*); end

		def as_json(*)
			{ tts: tts }
		end

		def to_json(*args)
			as_json.to_json(*args)
		end
	end

	class Unsupported
		CallAttempt.register do |supported:, direction:, **|
			new(direction: direction) unless supported
		end

		value_semantics do
			direction Either(:inbound, :outbound)
		end

		def view
			"#{direction}/unsupported"
		end

		def tts
			TTSTemplate.new(view).tts(self)
		end

		def to_render
			[view]
		end

		def to_s
			"Unsupported"
		end

		def create_call(*); end

		def as_json(*)
			{ tts: tts }
		end

		def to_json(*args)
			as_json.to_json(*args)
		end
	end

	class NoBalance
		CallAttempt.register do |credit:, rate:, **kwargs|
			self.for(rate: rate, **kwargs) if credit < rate * 10
		end

		def self.for(customer:, direction:, low_balance: LowBalance, **kwargs)
			low_balance.for(customer).then(&:notify!).then do |amount|
				if amount&.positive?
					CallAttempt.for(
						customer: customer.with_balance(customer.balance + amount),
						**kwargs.merge(direction: direction)
					)
				else
					NoBalance.new(balance: customer.balance, direction: direction)
				end
			end
		end

		value_semantics do
			balance Numeric
			direction Either(:inbound, :outbound)
		end

		def view
			"#{direction}/no_balance"
		end

		def tts
			TTSTemplate.new(view).tts(self)
		end

		def to_render
			[view, { locals: to_h }]
		end

		def to_s
			"NoBalance"
		end

		def create_call(*); end

		def as_json(*)
			{ tts: tts }
		end

		def to_json(*args)
			as_json.to_json(*args)
		end
	end

	class AtLimit
		value_semantics do
			customer_id String
			from String
			to(/\A\+\d+\Z/)
			call_id String
			direction Either(:inbound, :outbound)
			limit_remaining Integer
			max_minutes Integer
		end

		CallAttempt.register do |digits: nil, limit_remaining:, customer:, **kwargs|
			if digits != "1" && limit_remaining < 10
				new(
					**kwargs
						.merge(
							limit_remaining: limit_remaining,
							customer_id: customer.customer_id
						).slice(*value_semantics.attributes.map(&:name))
				)
			end
		end

		def view
			"#{direction}/at_limit"
		end

		def tts
			TTSTemplate.new(view).tts(self)
		end

		def to_render
			[view, { locals: to_h }]
		end

		def to_s
			"AtLimit(max_minutes: #{max_minutes}, "\
			"limit_remaining: #{limit_remaining})"
		end

		def create_call(fwd, *args, &block)
			fwd.create_call(*args, &block)
		end

		def as_json(*)
			{
				tts: tts,
				from: from,
				to: to,
				customer_id: customer_id,
				limit_remaining: limit_remaining,
				max_minutes: max_minutes
			}
		end

		def to_json(*args)
			as_json.to_json(*args)
		end
	end

	register do |customer:, **kwargs|
		new(
			**kwargs
				.merge(customer_id: customer.customer_id)
				.slice(*value_semantics.attributes.map(&:name))
		)
	end
end