Parse metadata from MO file

src/kielet/mo.gleam

@@ -32,6 +32,8 @@ pub type ParseError {
   OffsetPastEnd(Int)
   MalformedOffsetTableEntry(BitArray)
   StringNotUTF8(BitArray)
+  MetaItemMissing
+  MetaItemIsNotSingular
 }
 
 pub type Revision {
@@ -49,8 +51,16 @@ pub type Header {
   )
 }
 
+pub type MetaData =
+  Dict(String, String)
+
 pub type Mo {
-  Mo(endianness: Endianness, header: Header, translations: Translations)
+  Mo(
+    endianness: Endianness,
+    header: Header,
+    translations: Translations,
+    metadata: MetaData,
+  )
 }
 
 pub fn parse(mo: BitArray) {
@@ -62,7 +72,12 @@ pub fn parse(mo: BitArray) {
   )
   use <- bool.guard(
     header.string_count == 0,
-    Ok(Mo(endianness: endianness, header: header, translations: dict.new())),
+    Ok(Mo(
+      endianness: endianness,
+      header: header,
+      translations: dict.new(),
+      metadata: dict.new(),
+    )),
   )
 
   let total_size = bit_array.byte_size(mo)
@@ -81,8 +96,14 @@ pub fn parse(mo: BitArray) {
   )
 
   use translations <- result.try(parse_translations(endianness, header, mo))
+  use metadata <- result.try(parse_metadata(translations))
 
-  Ok(Mo(endianness: endianness, header: header, translations: translations))
+  Ok(Mo(
+    endianness: endianness,
+    header: header,
+    translations: translations,
+    metadata: metadata,
+  ))
 }
 
 fn parse_magic(body: BitArray) {
@@ -226,6 +247,35 @@ fn parse_mo_string(mo: BitArray, length: Int, offset: Int) {
   }
 }
 
+fn parse_metadata(translations) {
+  use meta <- result.try(
+    dict.get(translations, "")
+    |> result.replace_error(MetaItemMissing),
+  )
+  case meta {
+    Plural(..) -> Error(MetaItemIsNotSingular)
+    Singular(content: content, ..) -> {
+      let metadata =
+        content
+        |> string.split("\n")
+        |> list.map(fn(line) { string.split(line, ":") })
+        |> list.map(fn(item) {
+          case item {
+            [] -> #("", "")
+            [key] -> #(string.trim(key), "")
+            [key, ..rest] -> #(
+              string.trim(key),
+              string.trim(string.join(rest, ":")),
+            )
+          }
+        })
+        |> dict.from_list()
+
+      Ok(metadata)
+    }
+  }
+}
+
 fn le_int_8(int8: BitArray) {
   case int8 {
     <<l:size(8), h:size(8)>> -> Ok(reconstruct_ui8(h, l))