local M = {}
local linters_by_ft = {}

local null_ls = require "null-ls"
local services = require "lsp.null-ls.services"
local Log = require("core.log")

local function list_names(linters, option)
  option = option or {}
  local filter = option.filter or "supported"

  return vim.tbl_keys(linters[filter])
end

function M.list_supported_names(filetype)
  if not linters_by_ft[filetype] then
    return {}
  end
  return list_names(linters_by_ft[filetype], { filter = "supported" })
end

function M.list_unsupported_names(filetype)
  if not linters_by_ft[filetype] then
    return {}
  end
  return list_names(linters_by_ft[filetype], { filter = "unsupported" })
end

function M.list_available(filetype)
  local linters = {}
  for _, provider in pairs(null_ls.builtins.diagnostics) do
    -- TODO: Add support for wildcard filetypes
    if vim.tbl_contains(provider.filetypes or {}, filetype) then
      table.insert(linters, provider.name)
    end
  end

  return linters
end

function M.list_configured(linter_configs)
  local linters, errors = {}, {}

  for _, lnt_config in pairs(linter_configs) do
    local linter = null_ls.builtins.diagnostics[lnt_config.exe]

    if not linter then
      Log:error("Not a valid linter: " .. lnt_config.exe)
      errors[lnt_config.exe] = {} -- Add data here when necessary
    else
      local linter_cmd = services.find_command(linter._opts.command)
      if not linter_cmd then
        Log:warn("Not found: " .. linter._opts.command)
        errors[lnt_config.exe] = {} -- Add data here when necessary
      else
        Log:debug("Using linter: " .. linter_cmd)
        linters[lnt_config.exe] = linter.with {
          command = linter_cmd,
          extra_args = lnt_config.args,
        }
      end
    end
  end

  return { supported = linters, unsupported = errors }
end

function M.setup(filetype, option)
  if not options.lang[filetype] or (linters_by_ft[filetype] and not option.force_reload) then
    return
  end

  linters_by_ft[filetype] = M.list_configured(options.lang[filetype].linters)
  null_ls.register { sources = linters_by_ft[filetype].supported }
end

return M