-- Minimal JSON encoder for CoaExporter

local function escape_str(s)
    s = tostring(s)
    s = s:gsub('\\', '\\\\')
    s = s:gsub('"', '\\"')
    s = s:gsub('\n', '\\n')
    s = s:gsub('\r', '\\r')
    s = s:gsub('\t', '\\t')
    return '"' .. s .. '"'
end

local function is_array(t)
    if type(t) ~= 'table' then return false end
    local n = 0
    for k, _ in pairs(t) do
        if type(k) ~= 'number' then return false end
        n = n + 1
    end
    for i = 1, n do
        if t[i] == nil then return false end
    end
    return true
end

local function encode_value(v)
    local tv = type(v)
    if tv == 'nil' then
        return 'null'
    elseif tv == 'boolean' then
        return v and 'true' or 'false'
    elseif tv == 'number' then
        return tostring(v)
    elseif tv == 'string' then
        return escape_str(v)
    elseif tv == 'table' then
        if is_array(v) then
            local parts = {}
            for i = 1, #v do
                parts[#parts+1] = encode_value(v[i])
            end
            return '[' .. table.concat(parts, ',') .. ']'
        else
            local parts = {}
            for k, val in pairs(v) do
                local key = escape_str(k)
                parts[#parts+1] = key .. ':' .. encode_value(val)
            end
            return '{' .. table.concat(parts, ',') .. '}'
        end
    else
        return 'null'
    end
end

function CoaExporter_Json_Encode(obj)
    return encode_value(obj)
end