-- Reads memory keys "habit_streak.<habit>.<YYYY-MM-DD>" and computes streak per habit.
local t = jarvis.context.time

local function date_offset(days_back)
    -- Simple naive backwards calc (no calendar arithmetic — close enough for streaks)
    local jd_today = t.year * 365 + math.floor(t.year / 4)
                       + ({0,31,59,90,120,151,181,212,243,273,304,334})[t.month]
                       + (t.day - 1)
    local target_jd = jd_today - days_back
    -- Convert back to YYYY-MM-DD (approximate)
    local y = math.floor(target_jd / 365.25)
    local doy = target_jd - math.floor(y * 365.25)
    local month_starts = {0,31,59,90,120,151,181,212,243,273,304,334}
    local mo = 12
    for i = 12, 1, -1 do
        if doy >= month_starts[i] then mo = i; doy = doy - month_starts[i]; break end
    end
    return string.format("%04d-%02d-%02d", y, mo, doy + 1)
end

local all = jarvis.memory.all()

-- Group keys by habit name
local by_habit = {}
for _, rec in ipairs(all) do
    local habit, date = rec.key:match("^habit_streak%.([^%.]+)%.(.+)$")
    if habit and date then
        by_habit[habit] = by_habit[habit] or {}
        by_habit[habit][date] = true
    end
end

if next(by_habit) == nil then
    return jarvis.cmd.not_found("Привычек ещё не отмечено. Скажи 'выполнил привычку' после события.")
end

-- For each habit, count consecutive days back from today
local results = {}
for habit, dates in pairs(by_habit) do
    local streak = 0
    for d = 0, 30 do
        local key_date = date_offset(d)
        if dates[key_date] then
            streak = streak + 1
        else
            break
        end
    end
    table.insert(results, { habit = habit, streak = streak })
end

table.sort(results, function(a, b) return a.streak > b.streak end)

local sample = math.min(#results, 3)
local lines = {}
for i = 1, sample do
    local r = results[i]
    if r.streak == 0 then
        table.insert(lines, r.habit .. " прервана")
    else
        local d = r.streak == 1 and "день" or (r.streak < 5 and "дня" or "дней")
        table.insert(lines, r.habit .. " " .. r.streak .. " " .. d)
    end
end

return jarvis.cmd.ok("Стрики: " .. table.concat(lines, ", ") .. ".")