require 'lspconfig'
local configs = require 'lspconfig/configs'
local util = require 'lspconfig/util'
local inspect = vim.inspect
local uv = vim.loop
local fn = vim.fn
local tbl_flatten = vim.tbl_flatten

local function template(s, params)
  return (s:gsub("{{([^{}]+)}}", params))
end

local function map_list(t, func)
  local res = {}
  for i, v in ipairs(t) do
    local x = func(v, i)
    if x ~= nil then
      table.insert(res, x)
    end
  end
  return res
end

local function indent(n, s)
  local prefix
  if type(n) == 'number' then
    if n <= 0 then return s end
    prefix = string.rep(" ", n)
  else
    assert(type(n) == 'string', 'n must be number or string')
    prefix = n
  end
  local lines = vim.split(s, '\n', true)
  for i, line in ipairs(lines) do
    lines[i] = prefix..line
  end
  return table.concat(lines, '\n')
end

local function make_parts(fns)
  return tbl_flatten(map_list(fns, function(v)
    if type(v) == 'function' then
      v = v()
    end
    return {v}
  end))
end

local function make_section(indentlvl, sep, parts)
  return indent(indentlvl, table.concat(make_parts(parts), sep))
end

local function readfile(path)
  assert(util.path.is_file(path))
  return io.open(path):read("*a")
end

local function sorted_map_table(t, func)
  local keys = vim.tbl_keys(t)
  table.sort(keys)
  return map_list(keys, function(k)
    return func(k, t[k])
  end)
end

local lsp_section_template = [[
## {{template_name}}

{{preamble}}
```lua
require'lspconfig'.{{template_name}}.setup{}

{{body}}
```
]]

local function require_all_configs()
  -- Configs are lazy-loaded, tickle them to populate the `configs` singleton.
  for _,v in ipairs(vim.fn.glob('lua/lspconfig/*.lua', 1, 1)) do
    local module_name = v:gsub('.*/', ''):gsub('%.lua$', '')
    require('lspconfig/'..module_name)
  end
end

local function make_lsp_sections()
  return make_section(0, '\n', sorted_map_table(configs, function(template_name, template_object)
    local template_def = template_object.document_config
    local docs = template_def.docs

    local params = {
      template_name = template_name;
      preamble = "";
      body = "";
    }

    params.body = make_section(2, '\n\n', {
      function()
        if not template_def.commands then return end
        return make_section(0, '\n', {
          "Commands:";
          sorted_map_table(template_def.commands, function(name, def)
            if def.description then
              return string.format("- %s: %s", name, def.description)
            end
            return string.format("- %s", name)
          end)
        })
      end;
      function()
        if not template_def.default_config then return end
        return make_section(0, '\n', {
          "Default Values:";
          sorted_map_table(template_def.default_config, function(k, v)
            local description = ((docs or {}).default_config or {})[k]
            if description and type(description) ~= 'string' then
              description = inspect(description)
            elseif not description and type(v) == "function" then
              local info = debug.getinfo(v)
              local file = io.open(string.sub(info.source, 2), 'r')

              local fileContent = {}
              for line in file:lines() do
                table.insert (fileContent, line)
              end
              io.close(file)

              local root_dir = {}
              for i = info.linedefined, info.lastlinedefined do
                table.insert(root_dir, fileContent[i])
              end

              description = table.concat(root_dir, '\n')
              description = string.gsub(description, ".*function", "function")
            end
            return indent(2, string.format("%s = %s", k, description or inspect(v)))
          end)
        })
      end;
    })

    if docs then
      local tempdir = os.getenv("DOCGEN_TEMPDIR") or uv.fs_mkdtemp("/tmp/nvim-lsp.XXXXXX")
      local preamble_parts = make_parts {
        function()
          if docs.description and #docs.description > 0 then
            return docs.description
          end
        end;
        function()
          local package_json_name = util.path.join(tempdir, template_name..'.package.json');
          if docs.package_json then
            if not util.path.is_file(package_json_name) then
              os.execute(string.format("curl -v -L -o %q %q", package_json_name, docs.package_json))
            end
            if not util.path.is_file(package_json_name) then
              print(string.format("Failed to download package.json for %q at %q", template_name, docs.package_json))
              os.exit(1)
              return
            end
            local data = fn.json_decode(readfile(package_json_name))
            -- The entire autogenerated section.
            return make_section(0, '\n', {
              -- The default settings section
              function()
                local default_settings = (data.contributes or {}).configuration
                if not default_settings.properties then return end
                -- The outer section.
                return make_section(0, '\n', {
                  'This server accepts configuration via the `settings` key.';
                  '<details><summary>Available settings:</summary>';
                  '';
                  -- The list of properties.
                  make_section(0, '\n\n', sorted_map_table(default_settings.properties, function(k, v)
                    local function tick(s) return string.format("`%s`", s) end
                    local function bold(s) return string.format("**%s**", s) end

                    -- https://github.github.com/gfm/#backslash-escapes
                    local function excape_markdown_punctuations(str)
                      local pattern = "\\(\\*\\|\\.\\|?\\|!\\|\"\\|#\\|\\$\\|%\\|'\\|(\\|)\\|,\\|-\\|\\/\\|:\\|;\\|<\\|=\\|>\\|@\\|\\[\\|\\\\\\|\\]\\|\\^\\|_\\|`\\|{\\|\\\\|\\|}\\)"
                      return fn.substitute(str, pattern, "\\\\\\0", "g")
                    end

                    -- local function pre(s) return string.format("<pre>%s</pre>", s) end
                    -- local function code(s) return string.format("<code>%s</code>", s) end
                    if not (type(v) == "table") then
                        return
                    end
                    return make_section(0, '\n', {
                      "- "..make_section(0, ': ', {
                        bold(tick(k));
                        function()
                          if v.enum then
                            return tick("enum "..inspect(v.enum))
                          end
                          if v.type then
                            return tick(table.concat(tbl_flatten{v.type}, '|'))
                          end
                        end;
                      });
                      '';
                      make_section(2, '\n\n', {
                        {v.default and "Default: "..tick(inspect(v.default, {newline='';indent=''}))};
                        {v.items and "Array items: "..tick(inspect(v.items, {newline='';indent=''}))};
                        {excape_markdown_punctuations(v.description)};
                      });
                    })
                  end));
                  '';
                  '</details>';
                })
              end;
            })
          end
        end
      }
      if not os.getenv("DOCGEN_TEMPDIR") then
        os.execute("rm -rf "..tempdir)
      end
      -- Insert a newline after the preamble if it exists.
      if #preamble_parts > 0 then table.insert(preamble_parts, '') end
      params.preamble = table.concat(preamble_parts, '\n')
    end

    return template(lsp_section_template, params)
  end))
end

local function make_implemented_servers_list()
  return make_section(0, '\n', sorted_map_table(configs, function(k)
    return template("- [{{server}}](#{{server}})", {server=k})
  end))
end

local function generate_readme(template_file, params)
  vim.validate {
    lsp_server_details = {params.lsp_server_details, 's'};
    implemented_servers_list = {params.implemented_servers_list, 's'};
  }
  local input_template = readfile(template_file)
  local readme_data = template(input_template, params)

  local writer = io.open("CONFIG.md", "w")
  writer:write(readme_data)
  writer:close()
end

require_all_configs()
generate_readme("scripts/README_template.md", {
  implemented_servers_list = make_implemented_servers_list();
  lsp_server_details = make_lsp_sections();
})

-- vim:et ts=2 sw=2