local h = require('u.renderer').h
local Renderer = require('u.renderer').Renderer
local tracker = require 'u.tracker'

-- Create a new, temporary, buffer to the side:
vim.cmd.vnew()
vim.bo.buftype = 'nofile'
vim.bo.bufhidden = 'wipe'
vim.bo.buflisted = false
local renderer = Renderer.new()

-- Create two signals:
local s_name = tracker.create_signal '[(name here)]'
local s_age = tracker.create_signal '[(age here)]'

-- Utility to trim brackets from strings:
local function trimb(s) return (s:gsub('^%[(.*)%]$', '%1')) end

-- Render effect that depends on the signals. This will re-run every time
-- one of the signals changes.
tracker.create_effect(function()
  local name = s_name:get()
  local age = s_age:get()

  -- Each time the signals change, we re-render the buffer:
  renderer:render {
    h.Type({}, '# Form Example'),
    '\n\n',

    -- Setting the `signal` attribute to a signal will cause the renderer to
    -- update the signal's value whenever text in the tag is changed. This lets
    -- us setup two-way data-binding between the buffer and the signals.
    { 'Name: ', h.Structure({ signal = s_name }, name) },
    '\n',
    { 'Age: ', h.Structure({ signal = s_age }, age) },

    '\n\n',

    -- Display the current values of the signals. If you change the values in
    -- the tags above, you can see the changes reflected here immediately.
    { 'Hello, "', trimb(name), '", you are "', trimb(age), '" years old.' },
  }
end)