local util = require "navigator.util"
local lsphelper = require "navigator.lspwrapper"
local locations_to_items = lsphelper.locations_to_items
local gui = require "navigator.gui"
local log = util.log
local TextView = require("guihua.textview")
-- callback for lsp definition, implementation and declaration handler
local definition_hdlr = util.mk_handler(function(err, locations, ctx, _)
  -- log(locations)
  if err ~= nil then
    vim.notify(err, ctx, vim.lsp.log_levels.WARN)
    return
  end
  if type(locations) == "number" then
    log(locations)
    log("unable to handle request")
  end
  if locations == nil or vim.tbl_isempty(locations) then
    vim.notify "Definition not found"
    return
  end
  if vim.tbl_islist(locations) then
    if #locations > 1 then
      local items = locations_to_items(locations)
      gui.new_list_view({items = items, api = 'Definition'})
    else
      vim.lsp.util.jump_to_location(locations[1])
    end
  else
    vim.lsp.util.jump_to_location(locations)
  end
end)

local function get_symbol()
  local currentWord = vim.fn.expand('<cword>')
  return currentWord
end

local function def_preview(timeout_ms)
  assert(#vim.lsp.buf_get_clients() > 0, "Must have a client running")
  local method = "textDocument/definition"
  local params = vim.lsp.util.make_position_params()
  local result = vim.lsp.buf_request_sync(0, method, params, timeout_ms or 1000)

  if result == nil or vim.tbl_isempty(result) then
    vim.notify("No result found: " .. method, vim.lsp.log_levels.WARN)
    return nil
  end

  log(result)
  local data = {}
  -- result = {vim.tbl_deep_extend("force", {}, unpack(result))}
  -- log("def-preview", result)
  for key, value in pairs(result) do
    if result[key] ~= nil and not vim.tbl_isempty(result[key]) then
      table.insert(data, value.result[1])
    end
  end

  if vim.tbl_isempty(data) then
    vim.notify("No result found: " .. method, vim.lsp.log_levels.WARN)
    return nil
  end

  local range = data[1].targetRange or data[1].range or data[1].targetSelectionRange

  local row = range.start.line
  -- in case there are comments
  row = math.max(row - 3, 1)
  local delta = range.start.line - row + 1
  local uri = data[1].uri or data[1].targetUri
  if not uri then
    return
  end
  local bufnr = vim.uri_to_bufnr(uri)
  if not vim.api.nvim_buf_is_loaded(bufnr) then
    vim.fn.bufload(bufnr)
  end

  local ok, parsers = pcall(require, "nvim-treesitter.parsers")
  local lines_num = 12
  if ok then
    local ts = require 'navigator.treesitter'
    local root = parsers.get_parser(bufnr)
    log(range)
    local def_node = ts.get_node_at_pos({range['start'].line, range['start'].character}, root)

    local sr, _, er, _ = ts.get_node_scope(def_node)
    log(sr, er)
    lines_num = math.max(lines_num, er - sr + 3) -- comments etc
  end

  -- TODO: 12 should be an option
  local definition = vim.api.nvim_buf_get_lines(bufnr, row, range["end"].line + lines_num, false)
  local def_line = vim.api.nvim_buf_get_lines(bufnr, range.start.line, range.start.line + 1, false)
  for _ = 1, math.min(3, #definition), 1 do
    if #definition[1] < 2 then
      table.remove(definition, 1)
      delta = delta - 1
    else
      break
    end
  end
  local width = 40
  local maxwidth = math.floor(vim.fn.winwidth(0) * 4 / 5)
  for key, value in pairs(definition) do
    -- log(key, value, width)
    width = math.max(width, #value + 4)
    width = math.min(maxwidth, width)
  end
  definition = vim.list_extend({"    [" .. get_symbol() .. "] Definition: "}, definition)
  local filetype = vim.api.nvim_buf_get_option(bufnr, "filetype")

  -- TODO multiple resuts?
  local opts = {
    relative = "cursor",
    style = "minimal",
    ft = filetype,
    rect = {width = width, height = #definition + 3},
    data = definition,
    enter = true,
    border = _NgConfigValues.border or "shadow"
  }

  TextView:new(opts)
  delta = delta + 1 -- header
  local cmd = "normal! " .. tostring(delta) .. "G"

  vim.cmd(cmd)
  vim.cmd('set cursorline')
  if #def_line > 0 then
    local niddle = require('guihua.util').add_escape(def_line[1])
    -- log(def_line[1], niddle)
    vim.fn.matchadd("Search", niddle)
  end
  -- TODO:
  -- https://github.com/oblitum/goyo.vim/blob/master/autoload/goyo.vim#L108-L135
end

local def = function()
  local bufnr = vim.api.nvim_get_current_buf()

  local ref_params = vim.lsp.util.make_position_params()
  vim.lsp.for_each_buffer_client(bufnr, function(client, client_id, _bufnr)
    if client.resolved_capabilities.goto_definition then
      client.request("textDocument/definition", ref_params, definition_hdlr, _bufnr)
    end
  end)

end

vim.lsp.handlers["textDocument/definition"] = definition_hdlr
return {
  definition = def,
  definition_handler = definition_hdlr,
  definition_preview = def_preview,
  declaration_handler = definition_hdlr,
  typeDefinition_handler = definition_hdlr
}