-- "Сколько будет 1000 долларов в рублях" / "переведи 50 евро в доллары"
-- Uses cbr-xml-daily.ru (CBR daily rates, JSON, no key, mirrors RU central bank).
local phrase = (jarvis.context.phrase or ""):lower()

-- Strip trigger words
local body = phrase:gsub("сколько будет", "")
                   :gsub("переведи", "")
                   :gsub("конвертируй", "")
                   :gsub("convert", "")
                   :gsub("how much is", "")
                   :gsub("^[%s,:%.]+", "")
                   :gsub("%s+$", "")

-- Extract amount (digit or russian "сто", "тысяча" — keep simple, digits only)
local amount_str = body:match("([%d%.,]+)")
if not amount_str then
    jarvis.speak("Не понял сумму.")
    jarvis.audio.play_error()
    return { chain = false }
end
local amount = tonumber((amount_str:gsub(",", ".")))
if not amount then
    jarvis.speak("Не понял сумму.")
    jarvis.audio.play_error()
    return { chain = false }
end

-- Detect source + target currencies via heuristic substring matches.
local function detect(text)
    if text:find("доллар") or text:find("usd") or text:find("dollar") then return "USD" end
    if text:find("евро") or text:find("eur") or text:find("euro") then return "EUR" end
    if text:find("юан") or text:find("cny") or text:find("yuan") then return "CNY" end
    if text:find("фунт") or text:find("gbp") or text:find("pound") then return "GBP" end
    if text:find("иен") or text:find("jpy") or text:find("yen") then return "JPY" end
    if text:find("рубл") or text:find("rub") or text:find("ruble") then return "RUB" end
    return nil
end

-- Split on the conversion word "в"/"в"/"to"/"into" to detect from/to.
local from_part, to_part
local in_idx = body:find("%s+в%s+") or body:find("%s+to%s+") or body:find("%s+into%s+")
if in_idx then
    from_part = body:sub(1, in_idx - 1)
    to_part = body:sub(in_idx + 1)
else
    -- Heuristic: only one currency named → assume target RUB.
    from_part = body
    to_part = "рубли"
end

local from_ccy = detect(from_part)
local to_ccy = detect(to_part) or "RUB"
if not from_ccy then
    jarvis.speak("Не понял исходную валюту.")
    jarvis.audio.play_error()
    return { chain = false }
end

-- Fetch CBR rates (RUB-denominated).
local body_json = jarvis.http.get("https://www.cbr-xml-daily.ru/daily_json.js")
if not body_json or body_json == "" then
    jarvis.speak("Не получилось получить курсы.")
    jarvis.audio.play_error()
    return { chain = false }
end

-- We can't safely parse JSON without a Lua JSON lib. Use jarvis.http.json instead.
local data = jarvis.http.json("https://www.cbr-xml-daily.ru/daily_json.js")
if not data or not data.Valute then
    jarvis.speak("Не получилось разобрать ответ.")
    jarvis.audio.play_error()
    return { chain = false }
end

-- Each Valute entry: { Value=rub_per_unit, Nominal=N }. Effective rub_per_unit = Value/Nominal.
local function rub_per(ccy)
    if ccy == "RUB" then return 1.0 end
    local v = data.Valute[ccy]
    if not v then return nil end
    return v.Value / v.Nominal
end

local rub_from = rub_per(from_ccy)
local rub_to = rub_per(to_ccy)
if not rub_from or not rub_to then
    jarvis.speak("Этой валюты нет в курсах ЦБ.")
    jarvis.audio.play_error()
    return { chain = false }
end

local result = amount * rub_from / rub_to

-- Format pretty
local function fmt(n)
    if n >= 1000 then
        return string.format("%d", math.floor(n + 0.5))
    elseif n >= 10 then
        return string.format("%.1f", n)
    else
        return string.format("%.2f", n)
    end
end

local function unit(ccy, n)
    if ccy == "RUB" then return (n == 1 and "рубль" or (n < 5 and "рубля" or "рублей")) end
    if ccy == "USD" then return (n == 1 and "доллар" or (n < 5 and "доллара" or "долларов")) end
    if ccy == "EUR" then return "евро" end
    if ccy == "CNY" then return (n == 1 and "юань" or (n < 5 and "юаня" or "юаней")) end
    if ccy == "GBP" then return (n == 1 and "фунт" or (n < 5 and "фунта" or "фунтов")) end
    if ccy == "JPY" then return "иен" end
    return ccy
end

local result_int = math.floor(result + 0.5)
local line = string.format("%s %s — это %s %s.",
    fmt(amount), unit(from_ccy, amount),
    fmt(result), unit(to_ccy, result_int))

jarvis.speak(line)
jarvis.audio.play_ok()
return { chain = false }