feat: unified watch server under org-garden

org-garden/lib/org_garden/resolvers/bibtex.ex

@@ -0,0 +1,178 @@
+defmodule OrgGarden.Resolvers.BibTeX do
+  @moduledoc """
+  Resolves citation keys from a local BibTeX (.bib) file.
+
+  Configured via the `BIBTEX_FILE` environment variable, or passed directly
+  as `opts.bibtex_file`. The file is parsed once at init time and the
+  resulting entry map is reused for all lookups.
+
+  Supports extracting: author last names, year, title, DOI, URL.
+
+  BibTeX entry format parsed:
+
+      @type{citationkey,
+        author  = {Last, First and Last2, First2},
+        year    = {2021},
+        title   = {Some Title},
+        doi     = {10.xxxx/yyyy},
+        url     = {https://example.com},
+      }
+
+  Returns `{:ok, %{label: "Author, Year", url: "..."}}` or `:error`.
+  """
+
+  require Logger
+
+  # ------------------------------------------------------------------
+  # Public API
+  # ------------------------------------------------------------------
+
+  @doc """
+  Parse a .bib file and return a map of `%{citation_key => entry_map}`.
+  Returns `{:ok, entries}` or `{:error, reason}`.
+  """
+  @spec load(String.t()) :: {:ok, map()} | {:error, term()}
+  def load(path) do
+    case File.read(path) do
+      {:ok, content} ->
+        entries = parse_entries(content)
+        Logger.info("BibTeX: loaded #{map_size(entries)} entries from #{path}")
+        {:ok, entries}
+
+      {:error, reason} ->
+        {:error, reason}
+    end
+  end
+
+  @doc """
+  Resolve a citation key from pre-loaded BibTeX entries.
+  """
+  @spec resolve(String.t(), map()) :: {:ok, map()} | :error
+  def resolve(key, entries) do
+    case Map.fetch(entries, key) do
+      {:ok, entry} ->
+        label = build_label(entry)
+        url = build_url(entry)
+        {:ok, %{label: label, url: url}}
+
+      :error ->
+        :error
+    end
+  end
+
+  # ------------------------------------------------------------------
+  # Parsing
+  # ------------------------------------------------------------------
+
+  # Match @type{key, ...fields...}
+  # We handle nested braces by scanning character by character after
+  # finding the opening, rather than relying on a single regex.
+  @entry_header ~r/@\w+\s*\{\s*([^,\s]+)\s*,/
+
+  defp parse_entries(content) do
+    # Split on "@" boundaries, then parse each chunk
+    content
+    |> String.split(~r/(?=@\w+\s*\{)/, trim: true)
+    |> Enum.reduce(%{}, fn chunk, acc ->
+      case Regex.run(@entry_header, chunk) do
+        [_, key] ->
+          fields = parse_fields(chunk)
+          Map.put(acc, String.trim(key), fields)
+
+        _ ->
+          acc
+      end
+    end)
+  end
+
+  # Extract key = {value} or key = "value" pairs from an entry block.
+  # Handles simple single-depth braces; good enough for common fields.
+  @field_regex ~r/(\w+)\s*=\s*(?:\{([^{}]*(?:\{[^{}]*\}[^{}]*)*)\}|"([^"]*)")/
+
+  defp parse_fields(chunk) do
+    @field_regex
+    |> Regex.scan(chunk)
+    |> Enum.reduce(%{}, fn match, acc ->
+      field_name = Enum.at(match, 1) |> String.downcase()
+      # Value is in capture group 2 (braces) or 3 (quotes)
+      value =
+        case {Enum.at(match, 2, ""), Enum.at(match, 3, "")} do
+          {"", q} -> q
+          {b, _} -> b
+        end
+
+      Map.put(acc, field_name, String.trim(value))
+    end)
+  end
+
+  # ------------------------------------------------------------------
+  # Label & URL building
+  # ------------------------------------------------------------------
+
+  defp build_label(entry) do
+    author_part =
+      entry
+      |> Map.get("author", "")
+      |> parse_authors()
+      |> format_authors()
+
+    year = Map.get(entry, "year", Map.get(entry, "date", ""))
+    year = extract_year(year)
+
+    if year && author_part != "", do: "#{author_part}, #{year}", else: author_part
+  end
+
+  defp parse_authors(""), do: []
+
+  defp parse_authors(author_str) do
+    author_str
+    |> String.split(" and ", trim: true)
+    |> Enum.map(&extract_last_name/1)
+    |> Enum.reject(&(&1 == ""))
+  end
+
+  # Handles "Last, First" and "First Last" formats
+  defp extract_last_name(name) do
+    name = String.trim(name)
+
+    cond do
+      String.contains?(name, ",") ->
+        name |> String.split(",") |> List.first() |> String.trim()
+
+      String.contains?(name, " ") ->
+        name |> String.split(" ") |> List.last() |> String.trim()
+
+      true ->
+        name
+    end
+  end
+
+  defp format_authors([]), do: "Unknown"
+  defp format_authors([single]), do: single
+  defp format_authors([first | rest]), do: "#{first} & #{List.last(rest)}"
+
+  defp extract_year(""), do: nil
+
+  defp extract_year(str) do
+    case Regex.run(~r/\b(\d{4})\b/, str) do
+      [_, year] -> year
+      _ -> nil
+    end
+  end
+
+  defp build_url(entry) do
+    cond do
+      doi = Map.get(entry, "doi", "") |> non_empty() ->
+        "https://doi.org/#{doi}"
+
+      url = Map.get(entry, "url", "") |> non_empty() ->
+        url
+
+      true ->
+        nil
+    end
+  end
+
+  defp non_empty(""), do: nil
+  defp non_empty(v), do: v
+end