local M = {}

local tbl = require "lvim.utils.table"
local Log = require "lvim.core.log"

function M.is_client_active(name)
  local clients = vim.lsp.get_active_clients()
  return tbl.find_first(clients, function(client)
    return client.name == name
  end)
end

function M.get_active_clients_by_ft(filetype)
  local matches = {}
  local clients = vim.lsp.get_active_clients()
  for _, client in pairs(clients) do
    local supported_filetypes = client.config.filetypes or {}
    if client.name ~= "null-ls" and vim.tbl_contains(supported_filetypes, filetype) then
      table.insert(matches, client)
    end
  end
  return matches
end

function M.get_client_capabilities(client_id)
  local client
  if not client_id then
    local buf_clients = vim.lsp.buf_get_clients()
    for _, buf_client in pairs(buf_clients) do
      if buf_client.name ~= "null-ls" then
        client = buf_client
        break
      end
    end
  else
    client = vim.lsp.get_client_by_id(tonumber(client_id))
  end
  if not client then
    error "Unable to determine client_id"
    return
  end

  local enabled_caps = {}
  for capability, status in pairs(client.server_capabilities or client.resolved_capabilities) do
    if status == true then
      table.insert(enabled_caps, capability)
    end
  end

  return enabled_caps
end

---Get supported filetypes per server
---@param server_name string can be any server supported by nvim-lsp-installer
---@return string[] supported filestypes as a list of strings
function M.get_supported_filetypes(server_name)
  local status_ok, config = pcall(require, ("lspconfig.server_configurations.%s"):format(server_name))
  if not status_ok then
    return {}
  end

  return config.default_config.filetypes or {}
end

---Get supported servers per filetype
---@param filter { filetype: string | string[] }?: (optional) Used to filter the list of server names.
---@return string[] list of names of supported servers
function M.get_supported_servers(filter)
  local _, supported_servers = pcall(function()
    return require("mason-lspconfig").get_available_servers(filter)
  end)
  return supported_servers or {}
end

---Get all supported filetypes by nvim-lsp-installer
---@return string[] supported filestypes as a list of strings
function M.get_all_supported_filetypes()
  local status_ok, filetype_server_map = pcall(require, "mason-lspconfig.mappings.filetype")
  if not status_ok then
    return {}
  end
  return vim.tbl_keys(filetype_server_map or {})
end

function M.setup_document_highlight(client, bufnr)
  if lvim.builtin.illuminate.active then
    Log:debug "skipping setup for document_highlight, illuminate already active"
    return
  end
  local status_ok, highlight_supported = pcall(function()
    return client.supports_method "textDocument/documentHighlight"
  end)
  if not status_ok or not highlight_supported then
    return
  end
  local group = "lsp_document_highlight"
  local hl_events = { "CursorHold", "CursorHoldI" }

  local ok, hl_autocmds = pcall(vim.api.nvim_get_autocmds, {
    group = group,
    buffer = bufnr,
    event = hl_events,
  })

  if ok and #hl_autocmds > 0 then
    return
  end

  vim.api.nvim_create_augroup(group, { clear = false })
  vim.api.nvim_create_autocmd(hl_events, {
    group = group,
    buffer = bufnr,
    callback = vim.lsp.buf.document_highlight,
  })
  vim.api.nvim_create_autocmd("CursorMoved", {
    group = group,
    buffer = bufnr,
    callback = vim.lsp.buf.clear_references,
  })
end

function M.setup_document_symbols(client, bufnr)
  vim.g.navic_silence = false -- can be set to true to supress error
  local symbols_supported = client.supports_method "textDocument/documentSymbol"
  if not symbols_supported then
    Log:debug("skipping setup for document_symbols, method not supported by " .. client.name)
    return
  end
  local status_ok, navic = pcall(require, "nvim-navic")
  if status_ok then
    navic.attach(client, bufnr)
  end
end

function M.setup_codelens_refresh(client, bufnr)
  local status_ok, codelens_supported = pcall(function()
    return client.supports_method "textDocument/codeLens"
  end)
  if not status_ok or not codelens_supported then
    return
  end
  local group = "lsp_code_lens_refresh"
  local cl_events = { "BufEnter", "InsertLeave" }
  local ok, cl_autocmds = pcall(vim.api.nvim_get_autocmds, {
    group = group,
    buffer = bufnr,
    event = cl_events,
  })

  if ok and #cl_autocmds > 0 then
    return
  end
  vim.api.nvim_create_augroup(group, { clear = false })
  vim.api.nvim_create_autocmd(cl_events, {
    group = group,
    buffer = bufnr,
    callback = vim.lsp.codelens.refresh,
  })
end

---filter passed to vim.lsp.buf.format
---always selects null-ls if it's available and caches the value per buffer
---@param client table client attached to a buffer
---@return boolean if client matches
function M.format_filter(client)
  local filetype = vim.bo.filetype
  local n = require "null-ls"
  local s = require "null-ls.sources"
  local method = n.methods.FORMATTING
  local avalable_formatters = s.get_available(filetype, method)

  if #avalable_formatters > 0 then
    return client.name == "null-ls"
  elseif client.supports_method "textDocument/formatting" then
    return true
  else
    return false
  end
end

---Provide vim.lsp.buf.format for nvim <0.8
---@param opts table
function M.format(opts)
  opts = opts or {}
  opts.filter = opts.filter or M.format_filter

  if vim.lsp.buf.format then
    return vim.lsp.buf.format(opts)
  end

  local bufnr = opts.bufnr or vim.api.nvim_get_current_buf()

  ---@type table|nil
  local clients = vim.lsp.get_active_clients {
    id = opts.id,
    bufnr = bufnr,
    name = opts.name,
  }

  if opts.filter then
    clients = vim.tbl_filter(opts.filter, clients)
  end

  clients = vim.tbl_filter(function(client)
    return client.supports_method "textDocument/formatting"
  end, clients)

  if #clients == 0 then
    vim.notify_once "[LSP] Format request failed, no matching language servers."
  end

  local timeout_ms = opts.timeout_ms or 1000
  for _, client in pairs(clients) do
    local params = vim.lsp.util.make_formatting_params(opts.formatting_options)
    local result, err = client.request_sync("textDocument/formatting", params, timeout_ms, bufnr)
    if result and result.result then
      vim.lsp.util.apply_text_edits(result.result, bufnr, client.offset_encoding)
    elseif err then
      vim.notify(string.format("[LSP][%s] %s", client.name, err), vim.log.levels.WARN)
    end
  end
end

return M