local original_ngx = ngx
local function reset_ngx()
  _G.ngx = original_ngx
end

local function mock_ngx(mock)
  local _ngx = mock
  setmetatable(_ngx, { __index = ngx })
  _G.ngx = _ngx
end

describe("lua_ngx_var", function()
  local util = require("util")

  after_each(function()
    reset_ngx()
  end)

  describe("lua_ngx_var", function()
    before_each(function()
      mock_ngx({ var = { remote_addr = "192.168.1.1", [1] = "nginx/regexp/1/group/capturing" } })
    end)

    it("returns value of nginx var by key", function()
      assert.equal("192.168.1.1", util.lua_ngx_var("$remote_addr"))
    end)

    it("returns value of nginx var when key is number", function()
      assert.equal("nginx/regexp/1/group/capturing", util.lua_ngx_var("$1"))
    end)

    it("returns nil when variable is not defined", function()
      assert.equal(nil, util.lua_ngx_var("$foo_bar"))
    end)
  end)

  describe("diff_endpoints", function()
    it("returns removed and added endpoints", function()
      local old = {
        { address = "10.10.10.1", port = "8080" },
        { address = "10.10.10.2", port = "8080" },
        { address = "10.10.10.3", port = "8080" },
      }
      local new = {
        { address = "10.10.10.1", port = "8080" },
        { address = "10.10.10.2", port = "8081" },
        { address = "11.10.10.2", port = "8080" },
        { address = "11.10.10.3", port = "8080" },
      }
      local expected_added = { "10.10.10.2:8081", "11.10.10.2:8080", "11.10.10.3:8080" }
      table.sort(expected_added)
      local expected_removed = { "10.10.10.2:8080", "10.10.10.3:8080" }
      table.sort(expected_removed)

      local added, removed = util.diff_endpoints(old, new)
      table.sort(added)
      table.sort(removed)

      assert.are.same(expected_added, added)
      assert.are.same(expected_removed, removed)
    end)

    it("returns empty results for empty inputs", function()
      local added, removed = util.diff_endpoints({}, {})

      assert.are.same({}, added)
      assert.are.same({}, removed)
    end)

    it("returns empty results for same inputs", function()
      local old = {
        { address = "10.10.10.1", port = "8080" },
        { address = "10.10.10.2", port = "8080" },
        { address = "10.10.10.3", port = "8080" },
      }
      local new = util.deepcopy(old)

      local added, removed = util.diff_endpoints(old, new)

      assert.are.same({}, added)
      assert.are.same({}, removed)
    end)

    it("handles endpoints with nil attribute", function()
      local old = {
        { address = nil, port = "8080" },
        { address = "10.10.10.2", port = "8080" },
        { address = "10.10.10.3", port = "8080" },
      }
      local new = util.deepcopy(old)
      new[2].port = nil

      local added, removed = util.diff_endpoints(old, new)
      assert.are.same({ "10.10.10.2:nil" }, added)
      assert.are.same({ "10.10.10.2:8080" }, removed)
    end)
  end)
end)