Module:Kru-IPA

local export = {}

-- Helper function to strip whitespace and clean up raw template string inputs
local function clean_input(str)
    if not str then return "" end
    -- Remove leading/trailing spaces and strip out literal wiki formatting if accidentally passed
    str = str:gsub("^%s*(.-)%s*$", "%1")
    return str:lower()
end

function export.generate(frame)
    -- Fetch parameters from either direct invoke or parent template context
    local args = frame.args[1] and frame.args or frame:getParent().args
    local raw_text = args[1] or ""
    
    local ipa = clean_input(raw_text)
    if ipa == "" then 
        return "<span class='error'>Error: No text string provided to Module:kru-IPA</span>" 
    end

    -- 1. VOWELS (ISO 15919 long vowels mapped to standard IPA length marks)
    ipa = ipa:gsub("ā", "aː")
             :gsub("ī", "iː")
             :gsub("ū", "uː")
             :gsub("ē", "eː")
             :gsub("ō", "oː")

    -- 2. COMPLEX CONSONANT CLUSTERS, FRICATIVES & ALLOPHONIC AFFRICATES
    ipa = ipa:gsub("k͟h", "x")
             :gsub("kh", "x")
             :gsub("c", "t͡ɕ~t͡ʃ")
             :gsub("j", "d͡ʑ~d͡ʒ")
             :gsub("d̪", "t̪") -- Multi-grapheme dental allophone collapses straight to /t̪/

    -- 3. SEGREGATION MATRIX (Isolators for Alveolars and Custom Approximants)
    -- Protects your true Alveolar phonemes and their exact allophones from clashing with dental rules
    ipa = ipa:gsub("r̤", "D")   -- Custom r̤ -> Placeholder D (will become /ɻ/)
    ipa = ipa:gsub("ṯ", "A")   -- Voiceless Alveolar Phoneme ṯ -> Placeholder A (will become /t/)
    ipa = ipa:gsub("ḏ", "A")   -- Voiced Alveolar Allophone ḏ -> Placeholder A (collapses to /t/)
    ipa = ipa:gsub("ṉ", "B")   -- Alveolar Nasal ṉ -> Placeholder B (will become /n/)
    ipa = ipa:gsub("ṟ", "C")   -- Alveolar Trill ṟ -> Placeholder C (will become /r/)

    -- 4. PRIMARY REPLACEMENTS (Dentals, Retroflex Plosives, Nasals, and Taps)
    -- Bilabial & Velar Allophone to Phoneme Collapse
    ipa = ipa:gsub("b", "p")
    ipa = ipa:gsub("g", "k")
    
    -- Dental Group: Plain 't' is phoneme /t̪/. Plain 'd' is allophone, collapsing to /t̪/
    ipa = ipa:gsub("t", "t̪")
    ipa = ipa:gsub("d", "t̪")
    
    -- Retroflex Group: Plain 'ṭ' is phoneme /ʈ/. Plain 'ḍ' is allophone, collapsing to /ʈ/
    ipa = ipa:gsub("ṭ", "ʈ")
    ipa = ipa:gsub("ḍ", "ʈ")
    
    -- Nasals, Liquids & Flaps (Using unique wrapper for ṇ to block dental 'n' interference)
    ipa = ipa:gsub("n", "n̪")
    ipa = ipa:gsub("r", "ɾ")
    ipa = ipa:gsub("ṇ", "<b>ɳ</b>") 
    ipa = ipa:gsub("ḷ", "ɭ")
    ipa = ipa:gsub("ñ", "ɲ")
    ipa = ipa:gsub("ṅ", "ŋ")
    ipa = ipa:gsub("ṛ", "ɽ")
    
    -- Rest of the Consonants from your Global Matrix
    ipa = ipa:gsub("m", "m")    -- Bilabial Nasal
    ipa = ipa:gsub("w", "w")    -- Bilabial Central Approximant
    ipa = ipa:gsub("s", "s")    -- Alveolar Fricative
    ipa = ipa:gsub("l", "l")    -- Alveolar Lateral Approximant
    ipa = ipa:gsub("y", "j")    -- Palatal Central Approximant (y -> /j/)
    ipa = ipa:gsub("h", "h")    -- Glottal Fricative

    -- 5. MATRIX RESOLUTION (Converting tokens back into targeted true phonemes)
    ipa = ipa:gsub("A", "t")   -- Pure Voiceless Alveolar Stop Phoneme /t/ (from ṯ and ḏ)
    ipa = ipa:gsub("B", "n")   -- Pure Alveolar Nasal Phoneme /n/ (from ṉ)
    ipa = ipa:gsub("C", "r")   -- Pure Alveolar Trill Phoneme /r/ (from ṟ)
    ipa = ipa:gsub("D", "ɻ")   -- Pure Retroflex Approximant Phoneme /ɻ/ (from r̤)
    ipa = ipa:gsub("<b>#</b>", "ɳ") -- Restores retroflex nasal safely
    ipa = ipa:gsub("<b>ɳ</b>", "ɳ") 

    -- Wrap output in standard phonetic slashes for dictionary use
    return "/" .. ipa .. "/"
end

return export