local M = {}

local modes = {
  n = { "NORMAL", "StatuslineModeNormal" },
  i = { "INSERT", "StatuslineModeInsert" },
  v = { "VISUAL", "StatuslineModeVisual" },
  V = { "V-LINE", "StatuslineModeVisual" },
  [""] = { "V-BLOCK", "StatuslineModeVisual" },
  R = { "REPLACE", "StatuslineModeReplace" },
  c = { "COMMAND", "StatuslineModeCommand" },
}

local function mode()
  local m = vim.fn.mode()
  local entry = modes[m] or { m, "StatusLine" }
  return string.format("%%#%s# %s %%#StatusLine#", entry[2], entry[1])
end

----------------------------------------------------------------------
-- Statusline-Sektionen (reine Darstellung, keine IO)
----------------------------------------------------------------------

-- Git-Branch (gitsigns setzt vim.b.gitsigns_head asynchron pro Buffer)

local function git()
  local head = vim.b.gitsigns_head

  if not head or head == "" then return "" end

  return "  " .. head .. " "
end

-- Git-Diff (buffer-lokal, kein redraw-spam)

local function git_diff()
  local gsd = vim.b.gitsigns_status_dict
  if not gsd then return "" end

  local parts = {}
  if gsd.added and gsd.added > 0 then table.insert(parts, "+" .. gsd.added) end
  if gsd.changed and gsd.changed > 0 then table.insert(parts, "~" .. gsd.changed) end
  if gsd.removed and gsd.removed > 0 then table.insert(parts, "-" .. gsd.removed) end

  if #parts > 0 then return " " .. table.concat(parts, " ") .. " " end

  return ""
end

------------------------------------------------------------------------
-- Treesitter-Aktivität (buffer-lokal, kein redraw-spam)
------------------------------------------------------------------------

local function treesitter()
  local ok = vim.treesitter.highlighter.active[vim.api.nvim_get_current_buf()]
  if ok then return " 🌳 " end
  return ""
end

------------------------------------------------------------------------
-- LSP-Clients des Buffers
------------------------------------------------------------------------

local function lsp()
  local clients = vim.lsp.get_clients({ bufnr = 0 })

  if #clients == 0 then return "" end

  local names = {}
  for _, client in ipairs(clients) do
    table.insert(names, client.name)
  end

  return " " .. table.concat(names, ", ") .. " "
end

------------------------------------------------------------------------
-- Diagnostik-Counts (buffer-lokal, kein redraw-spam)
------------------------------------------------------------------------

local function diagnostics()
  local counts = {
    error = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.ERROR }),
    warn = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.WARN }),
    info = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.INFO }),
    hint = #vim.diagnostic.get(0, { severity = vim.diagnostic.severity.HINT }),
  }

  local parts = {}

  if counts.error > 0 then table.insert(parts, "  " .. counts.error) end
  if counts.warn > 0 then table.insert(parts, "  " .. counts.warn) end
  if counts.info > 0 then table.insert(parts, "  " .. counts.info) end
  if counts.hint > 0 then table.insert(parts, "  " .. counts.hint) end

  if #parts > 0 then return " " .. table.concat(parts, " ") .. " " end

  return ""
end

------------------------------------------------------------------------
-- Filetype & Encoding (buffer-lokal, kein redraw-spam)
------------------------------------------------------------------------

local function fileinfo()
  local ft = vim.bo.filetype ~= "" and vim.bo.filetype or "none"
  local enc = vim.bo.fileencoding ~= "" and vim.bo.fileencoding or vim.o.encoding
  return string.format(" %s  %s ", ft, enc)
end

----------------------------------------------------------------------
-- Öffentliche Statusline-Funktion
----------------------------------------------------------------------

function M.statusline()
  return table.concat({
    -- LEFT: Mode & Context
    mode(),
    "%#PmenuSel#",
    git(),
    git_diff(),
    "%#StatusLine#",
    -- %f Dateiname, %m Modifikationsstatus; %(..%) faellt weg, wenn %m leer ist
    " %f%( %m%) ",

    "%=",

    -- RIGHT: Feedback & Meta
    diagnostics(),
    lsp(),
    treesitter(),
    fileinfo(),
    " %p%% ",
    " %l:%c ",
  })
end

return M