local al = advtrains.lines
local rwt = assert(advtrains.lines.rwt)

local MODE_NORMAL = 0 -- normální zastávka (výchozí nebo mezilehlá)
local MODE_REQUEST_STOP = 1 -- zastávka na znamení (mezilehlá)
local MODE_HIDDEN = 2 -- skrytá zastávka (výchozí nebo mezilehlá)
local MODE_DISABLED = 3 -- vypnutá zastávka (mezilehlá nebo koncová)
local MODE_FINAL = 4 -- koncová zastávka (linka zde jízdu končí)
local MODE_FINAL_HIDDEN = 5 -- koncová zastávka skrytá
local MODE_FINAL_CONTINUE = 6 -- koncová zastávka (vlak pokračuje jako jiná linka)

local simple_modes = {
    [MODE_NORMAL] = MODE_NORMAL,
    [MODE_REQUEST_STOP] = MODE_NORMAL,
    [MODE_HIDDEN] = MODE_NORMAL,
    [MODE_DISABLED] = MODE_DISABLED,
    [MODE_FINAL] = MODE_FINAL,
    [MODE_FINAL_HIDDEN] = MODE_FINAL,
    [MODE_FINAL_CONTINUE] = MODE_FINAL,
}

local current_passages = {--[[
    [train_id] = {[1] = rwtime, ..., [n] = rwtime (časy *odjezdu*, kromě koncových zastávek, kde jde o čas příjezdu)}
]]}

local last_passages = {--[[
    [linevar] = {
        [1..10] = {[1] = rwtime, ...} -- jízdy seřazeny od nejstarší (1) po nejnovější (až 10) podle odjezdu z výchozí zastávky
    }
]]}

local diakritika_na_velka = {
	["á"] = "Á", ["ä"] = "Ä", ["č"] = "Č", ["ď"] = "Ď", ["é"] = "É", ["Ě"] = "Ě", ["Í"] = "Í", ["ĺ"] = "Ĺ", ["ľ"] = "Ľ",
	["ň"] = "Ň", ["ó"] = "Ó", ["ô"] = "Ô", ["ŕ"] = "Ŕ", ["ř"] = "Ř", ["š"] = "Š", ["ť"] = "Ť", ["ú"] = "Ú", ["ů"] = "Ů",
	["ý"] = "Ý", ["ž"] = "Ž",
}

local debug_print_i = 0

-- LOCAL funkce:
-- =========================================================================
local function debug_print(s)
    debug_print_i = debug_print_i + 1
    -- core.chat_send_all("["..debug_print_i.."] "..tostring(s))
    return s
end

-- Je-li stn kód stanice, vrací její jméno, jinak vrací "???". stn může být i nil.
local function get_station_name(stn)
    local station = advtrains.lines.stations[stn or ""]
    if station ~= nil and station.name ~= nil then
        return station.name
    else
        return "???"
    end
end

local function na_velka_pismena(s)
	local l = #s
	local i = 1
	local res = ""
	local c
	while i <= l do
		c = diakritika_na_velka[s:sub(i, i + 1)]
		if c then
			res = res .. c
			i = i + 2
		else
			res = res .. s:sub(i, i)
			i = i + 1
		end
	end
	return string.upper(res)
end

--[[
    -- Vrací index následujícího výskytu 'stn' v seznamu zastávek podle linevar_def.
    -- Vrací i skryté zastávky, ale ne vypnuté.
    -- Je-li linevar_def == nil nebo stn == nil nebo stn == "", vrací nil.
    - line_status = table
    - linevar_def = table or nil
    - stn = string
    return: int or nil
]]
local function find_next_index(line_status, linevar_def, stn)
    assert(line_status)
    if linevar_def ~= nil and stn ~= nil and stn ~= "" then
        local stops = linevar_def.stops
        if line_status.linevar_index < #stops then
            for i = line_status.linevar_index + 1, #stops do
                local stop = stops[i]
                if stop.stn == stn and (stop.mode or MODE_NORMAL) ~= MODE_DISABLED then
                    return i
                end
            end
        end
    end
end

--[[
    Používá se na *nelinkový* vlak stojící na *neanonymní* zastávce.
    Zahájí jízdu na lince nalezené podle kombinace line/stn/rc, nebo vrátí false.
]]
local function line_start(train, stn, departure_rwtime)
    assert(train)
    assert(stn and stn ~= "")
    assert(departure_rwtime)
    local ls = al.get_line_status(train)
    if ls.linevar ~= nil then
        error("line_start() used on a train that is already on a line: "..dump2({train = train}))
    end
    local linevar, linevar_def = al.try_get_linevar(train.line, stn, train.routingcode)
    if linevar == nil or linevar_def.disabled then
        -- print("DEBUG: line_start() failed for "..(train.line or "").."/"..stn.."/"..(train.routingcode or ""))
        return false
    end
    ls.linevar = linevar
    ls.linevar_station = stn
    ls.linevar_index = 1
    ls.linevar_dep = departure_rwtime
    ls.linevar_last_dep = departure_rwtime
    ls.linevar_last_stn = stn
    train.text_outside = al.get_line_description(linevar_def, {
        line_number = true,
        last_stop = true,
        last_stop_prefix = "",
        last_stop_uppercase = true,
        train_name = true,
    })
    -- print("DEBUG: line_start(): "..dump2({train_id = train.id, line_status = ls}))
    return true
end

--[[
    Vrací:
    - "true", pokud má vlak zastavit
    - nil, pokud zastavit nemá
    - "on_request", pokud má zastavit na znamení, ale znamení zatím nebylo dáno
]]
local function should_stop(pos, stdata, train)
    if stdata == nil or stdata.stn == nil then
        -- print("DEBUG: should_stop() == false, because stdata is invalid!")
        return nil -- neplatná data
    end
	local n_trainparts = #assert(train.trainparts)
    -- vyhovuje počet vagonů?
    if not ((stdata.minparts or 0) <= n_trainparts and n_trainparts <= (stdata.maxparts or 128)) then
        -- print("DEBUG: should_stop("..stdata.stn..") == false, because n_trainparts is not in interval")
        return nil
    end
    local stn = assert(stdata.stn) -- zastávka stále může být anonymní
	local ls, linevar_def = al.get_line_status(train)
    local next_index
    if stn ~= "" then
        next_index = find_next_index(ls, linevar_def, stn)
    end
    -- jde o linkový vlak?
    if linevar_def ~= nil then
        if next_index == nil then
            -- print("DEBUG: should_stop("..stn..") == false, because linevar=='"..ls.linevar.."' and next_index == nil")
            return nil
        end
        local stop = assert(linevar_def.stops[next_index])
        if stop.pos ~= nil and stop.pos ~= string.format("%d,%d,%d", pos.x, pos.y, pos.z) then
            -- print("DEBUG: should_stop("..stn..") == false, because the stop is limited to position "..stop.pos)
            return nil
        end
        if stop.mode ~= nil and stop.mode == MODE_REQUEST_STOP then
            if ls.stop_request ~= nil then
                debug_print("Vlak "..train.id.." zastaví na zastávce na znamení.")
                return "true"
            else
                debug_print("Vlak "..train.id.." možná zastaví na zastávce na znamení.")
                return "on_request"
            end
        end
        -- print("DEBUG: should_stop("..stn..") == true for "..linevar_def.name)
        return "true"
        -- local result = next_index ~= nil -- zastávka má index => zastavit
        --[[
        if result then
            print("DEBUG: should_stop() == true, because linevar=='"..ls.linevar.."' and get_line_status() retuned next_index == "..next_index)
        else
            print("DEBUG: should_stop() == false, because linevar=='"..ls.linevar.."' and get_line_status() retuned next_index == nil")
        end
        ]]
        -- return result
        -- TODO: zastávky na znamení
    else
        local ars = stdata.ars
        -- vyhovuje vlak ARS pravidlům?
        local result = ars and (ars.default or advtrains.interlocking.ars_check_rule_match(ars, train))
        if result then
            return "true"
            -- print("DEBUG: should_stop("..stn..") == true, because linevar==nil and ARS rules match")
        else
            return nil
            -- print("DEBUG: should_stop("..stn..") == false, because linevar==nil and ARS rules don't match")
        end
    end
end

local function update_value(train, key, setting)
    if setting == "-" then
        train[key] = nil
    elseif setting ~= "" then
        train[key] = setting
    end
    return train[key]
end

--[[
    Pokud vlak jede na lince, odebere ho z této linky a vrátí true; jinak vrátí false.
]]
function al.cancel_linevar(train)
    local ls = train.line_status
    if ls == nil or ls.linevar == nil then return false end
    -- print("DEBUG: line_end(train_id = "..train.id..", linevar was: "..ls.linevar.."): "..dump2({line_status_old = ls}))
    ls.linevar = nil
    ls.linevar_station = nil
    ls.linevar_index = nil
    ls.linevar_dep = nil
    ls.linevar_last_dep = nil
    ls.linevar_last_stn = nil
    train.text_outside = ""
    return true
end

-- Vrací seznam názvů neskrytých zastávek, počínaje od uvedeného indexu.
-- Pokud by vrátila prázdný seznam, vrátí místo něj {"???"}.
function al.get_stop_names(linevar_def, start_index)
    local stations = advtrains.lines.stations
    local result = {}
    if linevar_def ~= nil then
        local stops = linevar_def.stops
        if start_index == nil then
            start_index = 1
        end
        for i = start_index, #stops do
            local stop = stops[i]
            if stop.mode == nil or (stop.mode ~= MODE_HIDDEN and stop.mode ~= MODE_FINAL_HIDDEN and stop.mode ~= MODE_DISABLED) then
                local station = stations[stop.stn]
                if station ~= nil and station.name ~= nil and station.name ~= "" then
                    table.insert(result, station.name)
                else
                    table.insert(result, "???")
                end
            end
        end
    end
    if result[1] == nil then
        result[1] = "???"
    end
    return result
end

--[[
    Vrací:
    a) index, stop_data -- pokud byla vyhovující další zastávka nalezena
    b) nil, nil -- pokud nalezena nebyla
]]
function al.get_next_stop(linevar_def, current_index, allow_hidden_stops)
    local stops = assert(linevar_def.stops)
    if current_index < #stops then
        for i = current_index + 1, #stops do
            local mode = stops[i].mode
            if mode == nil or (mode ~= MODE_DISABLED and ((mode ~= MODE_HIDDEN and mode ~= MODE_FINAL_HIDDEN) or allow_hidden_stops)) then
                return i, stops[i]
            end
        end
    end
    return nil, nil
end

--[[
    Vrací:
    a) index, stop_data -- pokud byla vyhovující koncová zastávka nalezena
    b) nil, nil -- pokud nalezena nebyla
]]
function al.get_terminus(linevar_def, current_index, allow_hidden_stops)
    local stops = assert(linevar_def.stops)
    if current_index < #stops then
        for i = current_index + 1, #stops do
            local mode = stops[i].mode
            if mode ~= nil and (mode == MODE_FINAL or mode == MODE_FINAL_CONTINUE or (mode == MODE_FINAL_HIDDEN and allow_hidden_stops)) then
                return i, stops[i]
            end
        end
    end
    return nil, nil
end

--[[
    options = {
        line_number = bool or nil, -- zahrnout do popisu číslo linky? nil => false
        first_stop = bool or nil, -- zahrnout do popisu název výchozí zastávky? nil => false
        last_stop = bool or nil, -- zahrnout do popisu název cílové zastávky? nil => true
        last_stop_prefix = string or nil, -- text před název cílové zastávky; nil => "⇒ "
        last_stop_uppercase = bool or nil, -- je-li true, název cílové zastávky se před uvedením převede na velká písmena
        train_name = bool or nil, -- zahrnout do popisu jméno vlaku, je-li k dispozici; nil => false
        train_name_prefix = string or nil, -- text před jméno vlaku; nil => "\n"
    }
]]
function al.get_line_description(linevar_def, options)
    local line, stn = al.linevar_decompose(linevar_def.name)
    if line == nil then
        return "???"
    end
    if options == nil then options = {} end
    local s1, s2, s3, s4
    if options.line_number then
        s1 = "["..line.."] "
    else
        s1 = ""
    end
    if options.first_stop then
        s2 = get_station_name(stn).." "
    else
        s2 = ""
    end
    if options.last_stop == nil or options.last_stop then
        s3 = "???"
        local terminus_index, terminus_data = al.get_terminus(linevar_def, 1, false)
        if terminus_index ~= nil then
            s3 = get_station_name(terminus_data.stn)
            if options.last_stop_uppercase then
                s3 = na_velka_pismena(s3)
            end
        end
        s3 = (options.last_stop_prefix or "⇒ ")..s3
    else
        s3 = ""
    end
    if options.train_name and linevar_def.train_name ~= nil then
        s4 = (options.train_name_prefix or "\n")..linevar_def.train_name
    else
        s4 = ""
    end
    return s1..s2..s3..s4
end

function al.get_stop_description(stop_data, next_stop_data)
    local s1, s2 = "", ""
    if stop_data ~= nil then
        local mode = stop_data.mode or MODE_NORMAL
        if mode ~= MODE_DISABLED and mode ~= MODE_HIDDEN and mode ~= MODE_FINAL_HIDDEN then
            s1 = get_station_name(stop_data.stn)
            if mode == MODE_FINAL or mode == MODE_FINAL_CONTINUE then
                s2 = "Koncová zastávka"
            end
        end
    end
    if next_stop_data ~= nil then
        local mode = next_stop_data.mode or MODE_NORMAL
        if mode ~= MODE_DISABLED and mode ~= MODE_HIDDEN and mode ~= MODE_FINAL_HIDDEN then
            s2 = "Příští zastávka/stanice: "..get_station_name(next_stop_data.stn)
            if mode == MODE_REQUEST_STOP then
                s2 = s2.." (na znamení)"
            end
        end
    end
    if s1 ~= "" and s2 ~= "" then
        return s1.."\n"..s2
    else
        return s1..s2
    end
end

--[[
    Není-li zpoždění k dispozici, vrací {text = ""}, jinak vrací:
    {
        has_delay = bool,
        delay = int,
        text = string,
    }
]]
function al.get_delay_description(line_status, linevar_def)
    assert(line_status)
    if linevar_def == nil then
        return {text = ""}
    end
    local expected_departure = line_status.linevar_dep + assert(linevar_def.stops[line_status.linevar_index]).dep
    local real_departure = line_status.linevar_last_dep
    local delay = real_departure - expected_departure
    if delay < -1 or delay > 10 then
        return {
            has_delay = true,
            delay = delay,
            text = "zpoždění "..delay.." sekund",
        }
    else
        return {
            has_delay = false,
            delay = delay,
            text = "bez zpoždění",
        }
    end
end

-- Pokud zadaná varianta linky existuje, vrátí:
--      linevar_def, linevar_station
-- Jinak vrací:
--      nil, nil
-- Je-li linevar_station == nil, doplní se z linevar. Je-li linevar == nil, vrátí nil, nil.
function al.try_get_linevar_def(linevar, linevar_station)
    if linevar == nil then
        -- print("DEBUG: try_get_linevar_def() => nil, because linevar == nil")
        return nil, nil
    end
    if linevar_station == nil then
        local line
        line, linevar_station = al.linevar_decompose(linevar)
        if line == nil then
            return nil, nil
        end
    end
    local t = advtrains.lines.stations[linevar_station]
    if t ~= nil then
        t = t.linevars
        if t ~= nil then
            return t[linevar], linevar_station
        -- else
            -- print("DEBUG: no linevars for linevar_station '"..linevar_station.."'")
        end
    -- else
        -- print("DEBUG: no data for linevar_station '"..linevar_station.."'")
    end
    return nil, nil
end

--[[
    Vrací:
    a) nil, nil, pokud daná kombinace line/stn/rc nemá definovanou variantu linky
    b) linevar, linevar_def, pokud má
]]
function al.try_get_linevar(line, stn, rc)
    if line ~= nil and line ~= "" and stn ~= nil and stn ~= "" then
        local linevar = line.."/"..stn.."/"..(rc or "")
        local result = al.try_get_linevar_def(linevar, stn)
        if result ~= nil then
            -- print("DEBUG: linevar combination found: "..dump2({linevar = linevar, line = line, stn = stn, rc = rc or "", linevar_def = result}))
            return linevar, result
        end
    end
    -- print("DEBUG: linevar combination not found for "..(line or "").."/"..(stn or "").."/"..(rc or ""))
    return nil, nil
end

--[[
    Vrací 2 hodnoty:
    - line_status = table -- tabulka train.line_status (může být prázdná)
    - linevar_def = table or nil -- jde-li o linkový vlak, vrací definici linevar, jinak nil
    Parametry:
    - train = table (train)
]]
function al.get_line_status(train)
    assert(train)
    if train.line_status == nil then
        train.line_status = {}
        -- print("DEBUG: new empty line_status created for train "..train.id)
        return train.line_status, nil
    end
    local ls = train.line_status
    if ls.linevar == nil then
        -- nelinkový vlak
        return ls, nil
    end
    local rwtime = rwt.to_secs(rwt.get_time())
    if rwtime - ls.linevar_dep >= 86400 then
        core.log("warning", "Train "..train.id.." put out of linevar '"..ls.linevar.."', because it was riding more then 24 hours.")
        al.cancel_linevar(train)
        return ls, nil
    end
    local linevar_def = al.try_get_linevar_def(ls.linevar, ls.linevar_station)
    if linevar_def == nil then
        core.log("warning", "Train "..train.id.." was riding a non-existent (undefined) line '"..tostring(ls.linevar).."'!")
        al.cancel_linevar(train)
    elseif linevar_def.stops[ls.linevar_index] == nil then
        core.log("warning", "Train "..train.id.." put out of linevar '"..ls.linevar.."', because its index "..ls.linevar_index.." became invalid.")
        al.cancel_linevar(train)
        linevar_def = nil
    else
        local train_line_prefix = (train.line or "").."/"
        if train_line_prefix ~= ls.linevar:sub(1, train_line_prefix:len()) then