Converts base language code to default dialect.

Uses predefined mapping for most common regional variants. Falls back to base code if no mapping exists.

Examples

iex> DialectMapper.base_to_dialect("en")
"en-US"

iex> DialectMapper.base_to_dialect("pt")
"pt-BR"

iex> DialectMapper.base_to_dialect("ja")
"ja"

iex> DialectMapper.base_to_dialect("xx")
"xx"

Gets the default dialects map.

Useful for debugging, testing, or documentation purposes.

Examples

iex> defaults = DialectMapper.default_dialects()
iex> defaults["en"]
"en-US"

iex> defaults["pt"]
"pt-BR"

Gets all available dialect codes for a base language.

Searches the predefined language list for all dialects matching the given base code.

Examples

iex> DialectMapper.dialects_for_base("en")
["en-US", "en-GB", "en-CA", "en-AU"]

iex> DialectMapper.dialects_for_base("es")
["es-ES", "es-MX", "es-AR", "es-CO"]

iex> DialectMapper.dialects_for_base("ja")
["ja"]

iex> DialectMapper.dialects_for_base("xx")
[]

Use Cases

• Populate user preference dropdown
• Admin analytics (dialects per base language)
• Migration tools (find affected users)

Extracts base language code from full dialect code.

Splits on hyphen and returns first part (lowercased). Handles both dialect codes (en-US) and base codes (en). Returns "en" as default fallback for nil and empty string values.

Examples

iex> DialectMapper.extract_base("en-US")
"en"

iex> DialectMapper.extract_base("es-MX")
"es"

iex> DialectMapper.extract_base("zh-Hans-CN")
"zh"

iex> DialectMapper.extract_base("ja")
"ja"

iex> DialectMapper.extract_base("EN-GB")
"en"

iex> DialectMapper.extract_base(nil)
"en"

iex> DialectMapper.extract_base("")
"en"

Counts how many entries share each base language code in a list of language entries. Used by language switchers to decide whether to show a country qualifier or just the bare language name.

Accepts both maps with atom-keyed :code (e.g. %Language{} structs) and string-keyed "code" (e.g. JSON-decoded settings). Entries without a recognizable code are skipped.

Examples

iex> DialectMapper.group_dialects_by_base([
...>   %{code: "en-US"},
...>   %{code: "en-GB"},
...>   %{code: "et-EE"}
...> ])
%{"en" => 2, "et" => 1}

iex> DialectMapper.group_dialects_by_base([])
%{}

Resolves the full dialect code for a base language URL.

The URL is authoritative: the base code maps straight to its default dialect via base_to_dialect/1. User locale preferences are deliberately NOT consulted here — locale resolution is URL-driven across both the LiveView mount and the HTTP plug (see the rationale in PhoenixKitWeb.Users.Auth). Resolving without a user keeps a logged-in user's custom_fields["preferred_locale"] from silently upgrading e.g. base "en" to "en-GB".

Examples

iex> DialectMapper.resolve_dialect("en")
"en-US"

iex> DialectMapper.resolve_dialect("es")
"es-ES"

iex> DialectMapper.resolve_dialect("ja")
"ja"

Validates if a base language code is supported.

Checks if the default dialect for this base code exists in the predefined language list.

Examples

iex> DialectMapper.valid_base_code?("en")
true

iex> DialectMapper.valid_base_code?("ja")
true

iex> DialectMapper.valid_base_code?("xx")
false

iex> DialectMapper.valid_base_code?("en-US")
false  # Not a base code (contains hyphen)

Notes

• Only validates base codes (2 letters)
• Full dialect codes will return false (use extract_base first)
• Checks against Languages.get_predefined_language/1