-- DuckDuckGo Instant Answer — short factual lookups WITHOUT an API key.
--
-- Endpoint: https://api.duckduckgo.com/?q=<query>&format=json&no_html=1
--
-- DDG returns a JSON object. We look at, in order:
--   1. `AbstractText` — Wikipedia-style summary, usually 1–3 sentences
--   2. `Answer`       — direct answer for math / conversion / calc queries
--   3. `Definition`   — dictionary definitions
--   4. `RelatedTopics[1].Text` — first related topic as last resort
--
-- If nothing useful comes back, we open the regular DDG search page so the
-- user can read it themselves.

local lang = jarvis.context.language
local raw = (jarvis.context.phrase or ""):lower()

local triggers = {
    "что такое", "кто такой", "кто такая",
    "расскажи про", "расскажи о",
    "найди информацию о", "найди информацию про",
    "поищи в интернете", "поищи в сети",
    "погугли что такое",
    "what is", "who is", "tell me about", "look up", "search the web for",
}
local query = jarvis.text.strip_trigger(raw, triggers)
if not query or query == "" then query = raw end
query = query:gsub("^%s+", ""):gsub("%s+$", "")

if query == "" then
    return jarvis.cmd.not_found(lang == "ru" and "Что искать?" or "What to look up?")
end

-- URL-encode (basic — DDG accepts both UTF-8 and percent-encoded)
local function url_encode(s)
    return (s:gsub("([^%w%-_%.~])", function(c)
        return string.format("%%%02X", string.byte(c))
    end))
end

local url = "https://api.duckduckgo.com/?q="
    .. url_encode(query)
    .. "&format=json&no_html=1&skip_disambig=1"

jarvis.log("info", "ddg query: " .. query)
local res = jarvis.http.get(url, { ["User-Agent"] = "Mozilla/5.0 J.A.R.V.I.S." })

if not res or not res.ok then
    return jarvis.cmd.error(lang == "ru" and "DDG не отвечает." or "DDG didn't respond.")
end

local body = res.body or ""

-- Helper: pull the first top-level JSON string field. Quick-and-dirty regex
-- works because DDG never nests the fields we care about, AND because
-- consequent `"` inside values are escaped as `\"`.
local function field(name)
    local pat = '"' .. name .. '"%s*:%s*"((\\.[^"]*|[^"])*)"'
    local v = body:match('"' .. name .. '"%s*:%s*"(.-)"')
    if not v or v == "" then return nil end
    -- unescape common JSON sequences
    v = v:gsub('\\"', '"'):gsub('\\\\', '\\'):gsub('\\n', ' '):gsub('\\t', ' ')
    -- trim, collapse whitespace
    v = v:gsub("%s+", " "):gsub("^%s+", ""):gsub("%s+$", "")
    if v == "" then return nil end
    return v
end

-- First related topic — array element is itself an object with "Text".
local function first_related()
    -- Find start of "RelatedTopics" array
    local start_idx = body:find('"RelatedTopics"%s*:%s*%[')
    if not start_idx then return nil end
    -- Look for the first Text inside that array
    local v = body:sub(start_idx):match('"Text"%s*:%s*"(.-)"')
    if not v or v == "" then return nil end
    v = v:gsub('\\"', '"'):gsub('\\\\', '\\'):gsub('\\n', ' '):gsub('\\t', ' ')
    v = v:gsub("%s+", " "):gsub("^%s+", ""):gsub("%s+$", "")
    -- Trim absurdly long blurbs to the first ~300 chars
    if #v > 320 then v = v:sub(1, 300) .. "…" end
    return v
end

local answer =
       field("AbstractText")
    or field("Answer")
    or field("Definition")
    or first_related()

if answer then
    jarvis.log("info", "ddg answer found, " .. #answer .. " chars")
    return jarvis.cmd.ok(answer)
end

-- Nothing useful — open the search page so the user can read raw results.
local fallback = "https://duckduckgo.com/?q=" .. url_encode(query)
jarvis.system.open(fallback)
return jarvis.cmd.ok(lang == "ru"
    and ("Ничего конкретного не нашёл, открываю поиск по запросу: " .. query)
    or  ("Nothing direct found, opening search for: " .. query))