local M = {}

---Show diagnostics in a floating window.
---@param opts table|nil: options passed along to `vim.diagnostic.open_float`.
M.open_float = function(opts) vim.diagnostic.open_float(opts) end

---Toggle diagnostics in the given buffer.
---@param bufnr integer|nil: Buffer number (0 for current buffer, nil for all buffers.
M.toggle = function(bufnr)
  local filter = { bufnr = bufnr or 0 }
  if vim.diagnostic.is_enabled(filter) then
    vim.diagnostic.enable(false, filter)
  else
    vim.diagnostic.enable(true, filter)
  end
end

---Hide currently displayed diagnostics.
---@param bufnr integer|nil: Buffer number (0 for current buffer, nil for all buffers.
M.hide = function(bufnr) vim.diagnostic.hide(nil, bufnr or 0) end

local icons = require("fschauen.util.icons")

---Use `Telescope` to set a new diagnostic severity.
M.set_severity = function()
  if not pcall(require, "telescope") then
    vim.notify("Telescope not available!", vim.log.levels.ERROR)
    return
  end

  local displayer = require("telescope.pickers.entry_display").create {
    separator = "",
    items = { { width = 3 }, { width = 3 }, { remaining = true } },
  }

  local make_display = function(entry)
    local severity = vim.F.npcall(
      function() return vim.diagnostic.config().signs.severity.min end
    )
    local marker = severity == entry.value.severity and icons.ui.Checkbox or ""
    return displayer {
      { marker, "Comment" },
      { entry.value.icon, entry.value.highlight },
      { entry.value.title, entry.value.highlight },
    }
  end

  local opts = require("telescope.themes").get_dropdown()
  require("telescope.pickers")
    .new(opts, {
      prompt_title = "Min. severity for virtual text:",
      finder = require("telescope.finders").new_table {
        results = {
          {
            title = "Off",
            severity = 0,
            icon = icons.ui.Off,
            highlight = "Comment",
          },
          {
            title = "Error",
            severity = vim.diagnostic.severity.ERROR,
            icon = icons.diagnostics_bold.Error,
            highlight = "DiagnosticError",
          },
          {
            title = "Warning",
            severity = vim.diagnostic.severity.WARN,
            icon = icons.diagnostics_bold.Warn,
            highlight = "DiagnosticWarn",
          },
          {
            title = "Info",
            severity = vim.diagnostic.severity.INFO,
            icon = icons.diagnostics_bold.Info,
            highlight = "DiagnosticInfo",
          },
          {
            title = "Hint",
            severity = vim.diagnostic.severity.HINT,
            icon = icons.diagnostics_bold.Hint,
            highlight = "DiagnosticHint",
          },
        },
        entry_maker = function(entry)
          return { value = entry, ordinal = entry.title, display = make_display }
        end,
      },
      sorter = require("telescope.config").values.generic_sorter(opts),
      attach_mappings = function(prompt_bufnr, _)
        local actions = require("telescope.actions")
        actions.select_default:replace(function()
          actions.close(prompt_bufnr)
          local selection = require("telescope.actions.state").get_selected_entry()
          M.setup { severity = { min = selection.value.severity } }
        end)
        return true
      end,
    })
    :find()
end

---Customize nvim's diagnostics display.
M.setup = function(opts)
  opts = vim.tbl_deep_extend("keep", opts or {}, {
    severity = {
      min = vim.diagnostic.severity.HINT,
    },
  })

  vim.diagnostic.config {
    underline = false,
    severity_sort = true,
    signs = {
      severity = opts.severity,
      text = {
        [vim.diagnostic.severity.ERROR] = icons.diagnostics.Error,
        [vim.diagnostic.severity.WARN] = icons.diagnostics.Warn,
        [vim.diagnostic.severity.INFO] = icons.diagnostics.Info,
        [vim.diagnostic.severity.HINT] = icons.diagnostics.Hint,
      },
    },
    virtual_text = {
      severity = opts.severity,
      prefix = function(_, index, total) return index == total and "▰" or "▱" end,
    },
    float = {
      border = "rounded",
      header = { " " .. icons.ui.Diagnostic .. "  Diagnostics:", "Comment" },
      prefix = function(_, index, _) return string.format("%2d. ", index), "Comment" end,
    },
    jump = {
      severity = opts.severity,
      wrap = false,
      float = true,
    },
  }
end

return M