-- partially imported from https://github.com/echasnovski/mini.nvim
local Helpers = {}

-- Add extra expectations
Helpers.expect = vim.deepcopy(MiniTest.expect)

-- The error message returned when a test fails.
local function errorMessage(str, pattern)
  return string.format("Pattern: %s\nObserved string: %s", vim.inspect(pattern), str)
end

-- Check equality of a global `field` against `value` in the given `child` process.
-- @usage global_equality(child, "_G.TextTransformLoaded", true)
Helpers.expect.global_equality = MiniTest.new_expectation(
  "variable in child process matches",
  function(child, field, value)
    return Helpers.expect.equality(child.lua_get(field), value)
  end,
  errorMessage
)

-- Check type equality of a global `field` against `value` in the given `child` process.
-- @usage global_type_equality(child, "_G.TextTransformLoaded", "boolean")
Helpers.expect.global_type_equality = MiniTest.new_expectation(
  "variable type in child process matches",
  function(child, field, value)
    return Helpers.expect.global_equality(child, "type(" .. field .. ")", value)
  end,
  errorMessage
)

-- Check equality of a config `field` against `value` in the given `child` process.
-- @usage option_equality(child, "debug", true)
Helpers.expect.config_equality = MiniTest.new_expectation(
  "config option matches",
  function(child, field, value)
    return Helpers.expect.global_equality(child, "_G.TextTransform.config." .. field, value)
  end,
  errorMessage
)

-- Check type equality of a config `field` against `value` in the given `child` process.
-- @usage config_type_equality(child, "debug", "boolean")
Helpers.expect.config_type_equality = MiniTest.new_expectation(
  "config option type matches",
  function(child, field, value)
    return Helpers.expect.global_equality(
      child,
      "type(_G.TextTransform.config." .. field .. ")",
      value
    )
  end,
  errorMessage
)

-- Check equality of a state `field` against `value` in the given `child` process.
-- @usage state_equality(child, "enabled", true)
Helpers.expect.state_equality = MiniTest.new_expectation(
  "state matches",
  function(child, field, value)
    return Helpers.expect.global_equality(child, "_G.TextTransform.enabled." .. field, value)
  end,
  errorMessage
)

-- Check type equality of a state `field` against `value` in the given `child` process.
-- @usage state_type_equality(child, "enabled", "boolean")
Helpers.expect.state_type_equality = MiniTest.new_expectation(
  "state type matches",
  function(child, field, value)
    return Helpers.expect.global_equality(
      child,
      "type(_G.TextTransform.state." .. field .. ")",
      value
    )
  end,
  errorMessage
)

Helpers.expect.match = MiniTest.new_expectation("string matching", function(str, pattern)
  return str:find(pattern) ~= nil
end, errorMessage)

Helpers.expect.no_match = MiniTest.new_expectation("no string matching", function(str, pattern)
  return str:find(pattern) == nil
end, errorMessage)

-- Monkey-patch `MiniTest.new_child_neovim` with helpful wrappers
Helpers.new_child_neovim = function()
  local child = MiniTest.new_child_neovim()

  local prevent_hanging = function(method)
    -- stylua: ignore
    if not child.is_blocked() then return end

    local msg = string.format("Can not use `child.%s` because child process is blocked.", method)
    error(msg)
  end

  child.setup = function()
    child.restart({ "-u", "scripts/minimal_init.lua" })

    -- Change initial buffer to be readonly. This not only increases execution
    -- speed, but more closely resembles manually opened Neovim.
    child.bo.readonly = false
  end

  child.set_lines = function(arr, start, finish)
    prevent_hanging("set_lines")

    if type(arr) == "string" then
      arr = vim.split(arr, "\n")
    end

    child.api.nvim_buf_set_lines(0, start or 0, finish or -1, false, arr)
  end

  child.get_lines = function(start, finish)
    prevent_hanging("get_lines")

    return child.api.nvim_buf_get_lines(0, start or 0, finish or -1, false)
  end

  child.set_cursor = function(line, column, win_id)
    prevent_hanging("set_cursor")

    child.api.nvim_win_set_cursor(win_id or 0, { line, column })
  end

  child.get_cursor = function(win_id)
    prevent_hanging("get_cursor")

    return child.api.nvim_win_get_cursor(win_id or 0)
  end

  child.set_size = function(lines, columns)
    prevent_hanging("set_size")

    if type(lines) == "number" then
      child.o.lines = lines
    end

    if type(columns) == "number" then
      child.o.columns = columns
    end
  end

  child.get_size = function()
    prevent_hanging("get_size")

    return { child.o.lines, child.o.columns }
  end

  child.expect_screenshot = function(opts, path, screenshot_opts)
    if child.fn.has("nvim-0.8") == 0 then
      MiniTest.skip("Screenshots are tested for Neovim>=0.8 (for simplicity).")
    end

    MiniTest.expect.reference_screenshot(child.get_screenshot(screenshot_opts), path, opts)
  end

  return child
end

return Helpers