-- cache all existing barters, source of truth
barters = {}
-- list of all barters associated with trader (array index)
trader_to_barter = {}
-- track existing data when it comes to barters that have been partially completed n such, need to be reloaded, etc
barter_mdata = {
    fixed = {}, -- limited
    restock = {}, -- resets on restock
    give_items = {} -- locks the current give item if there is a pool
}

local ini_barters = ini_file("barter\\importer.ltx")
ini_parts = itms_manager.ini_parts
gc = game.translate_string
get_config = barter_mcm.get_config


local dbg_log
function print_dbg(msg, ...)

-- printf("barter | %s | " .. msg, time_global(), ...)
    if get_config("debug") then
        dbg_log = dbg_log or mcm_log and mcm_log.new("DBG")
        if dbg_log then --dbg_log then
            dbg_log.enabled = true
            dbg_log:log( msg , ...)
        else
            printf( "barter: | %s |  "..msg ,time_global(), ...)
        end
    end
    return nil
end

function get_desc(name)
    if ini_barters:r_string_ex(name, "repeat") and ini_barters:r_string_ex(name, "desc_done") and not check_limit(name) then
        return ini_barters:r_string_ex(name, "desc_done") or "st_generic_done"

    else
        return ini_barters:r_string_ex(name, "desc") or "st_ui_barter_rules"

    end
end

function npc_has_barter(npc)
    local name = ""
    if type(npc) == "string" then
        -- two cases for sid and forester
        if npc == "esc_2_12_stalker_trader" then name = "m_trader" 
        elseif npc == "red_forester_tech" then name = "m_lesnik" 
        else
            name = npc
        end
    else
        name = npc and npc:section() or ""
    end
    return trader_to_barter[name] and not is_empty(trader_to_barter[name])
end

-- yoink
function eval_func(f, ...)
    fc = str_explode(f, "%.")
    file, func = unpack(fc)
    if file and func and _G[file] and _G[file][func] then
        return _G[file][func](...)
    else
        print_dbg("Could not find function %s", f)
    end
end

local default_cond_funcs = {
    ["precondition"] = "barter_core.pre_std",
    ["postcondition"] = "barter_core.post_std",
    ["showcondition"] = "barter_core.check_pass",
}

-- barter name, "precondition"/*showocondition/"postcondition"
function eval_barter(name, condition)
    conds = ini_barters:r_string_ex(name, condition)
    if not conds then conds = default_cond_funcs[condition] or "barter_core.check_pass" end
    conds = str_explode(conds, ",")
    -- short circuit L->R evaluation
    local result = true
    for k,v in pairs(conds) do
        res = eval_func(v, name)
        if res then
            result = result and res
        else
            print_dbg("%s condition false", v)
            result = false 
        end
    end
    return result
end

local repeat_ranks = {
    ["inf"] = 3,
    ["restock"] = 2,
    ["fixed"] = 1
}

-- sorts barters
function sort_func(a, b)
    
    -- goodwill or hard rank
    local a_rep = ini_barters:r_float_ex(a.name, "sort_rank") or ini_barters:r_float_ex(a.name, "goodwill") or 0
    local b_rep = ini_barters:r_float_ex(b.name, "sort_rank") or ini_barters:r_float_ex(b.name, "goodwill") or 0
    if a_rep ~= b_rep then return a_rep < b_rep end
    -- repeat type
    local a_type = ini_barters:r_string_ex(a.name, "repeat") or "inf"
    local b_type = ini_barters:r_string_ex(b.name, "repeat") or "inf"
    if a_type ~= b_type then
        return repeat_ranks[a_type] > repeat_ranks[b_type]
    end
    -- repeat limit
    local a_limit = ini_barters:r_float_ex(a.name, "limit") or 0
    local b_limit = ini_barters:r_float_ex(b.name, "limit") or 0
    if a_limit ~= b_limit then return a_limit > b_limit end
    -- cost
    return (SYS_GetParam(2, a.give.sec, "cost") * a.give.amt) > (SYS_GetParam(2, b.give.sec, "cost") * b.give.amt)

end

-- get barter list with data on each barter
function get_barter_list(npc, random)
    printf("Checking barters for %s", npc:section())
    if not npc_has_barter(npc) then return {} end
    local name = npc:section()
    print_dbg("Fetching list for %s", npc:character_name())
    local barter_list = {}
    for k,v in pairs(trader_to_barter[name]) do
        print_dbg("Loading data for trade %s", v)
        local data = barter_get_data(v)
        if data and eval_barter(v, "showcondition") then table.insert(barter_list, data) end
    end

    table.sort(barter_list, sort_func)

    return barter_list
end

-- for a given barter, return data on barter eligibility and what items are taken
function barter_get_data(name)
    -- eval precond
    local allowed = eval_barter(name, "precondition")
    -- eval items
    local data = {}
    copy_table(data, barters[name])
    data.give = get_give_item(name)
    data.name = name
    -- sort rank is important as newlines will be inserted in differences between sort rank
    data.sort_rank = ini_barters:r_float_ex(name, "sort_rank") or ini_barters:r_float_ex(name, "goodwill") or 0
    data.amt = data.limit and get_barter_amt(name) or nil
    local take_items = {}
    for k,v in pairs(data.take) do
        take_items[k] = {
            sec = k,
            ids = {},
            amt = 0,
            limit = v
        }
        if k == "money" then
            take_items[k].amt = db.actor:money()
        end
        if IsItem("ammo", k) then
            take_items[k].limit = take_items[k].limit * SYS_GetParam(2, k, "box_size")
        end
    end
    db.actor:iterate_inventory(function(actor, item)
        local sec = item:section()
        local take_amt = data.take[sec]
        if not take_amt or take_amt == 0 then return end
        -- item specific stuff

        if IsItem("ammo", sec) and item:ammo_get_count() < item:ammo_box_size() then
            -- validate full box
            return
        end

        if item.condition then
            local cond_adj = math.ceil(item:condition()*100)
            if SYS_GetParam(1, item:section(), "cond_part") and cond_adj <= barter_mcm.get_config("cond_part") then return 
            elseif cond_adj <= barter_mcm.get_config("cond") then
            -- validate max condition
            return end
        end

        local has_parts = ini_parts:r_string_ex("con_parts_list",sec)
        if has_parts then
            local parts = item_parts.get_parts_con(item, nil, true)
            local part_cond = barter_mcm.get_config("cond_part")
            for k,v in pairs(parts) do
                if string.find(v, "prt_") and v <= part_cond then return end
            end
        end
        
        -- process multiuse items
        
        local item_data = take_items[sec]
        if item_data.limit > item_data.amt then
            table.insert(item_data.ids, item:id())
        end
        if IsItem("ammo", sec) then
            item_data.amt = item_data.amt + IsItem("ammo", sec)
        elseif IsItem("multiuse", sec) then
            item_data.amt = item_data.amt + item:get_remaining_uses()
        else
            item_data.amt = item_data.amt + 1
        end

    end)
    if data.type == "anyOf" then
        local at_least_one = false
        for k,v in pairs(take_items) do
            print_dbg("Actor has %s of %s of item %s for barter",v.amt, v.limit, k)
            if v.amt >= v.limit then
                at_least_one = true
            end
        end
        allowed = allowed and at_least_one
    else
        for k,v in pairs(take_items) do
            print_dbg("Actor has %s of %s of item %s for barter",v.amt, v.limit, k)
            if v.limit > v.amt then
                allowed = false
            end
        end
    end
    print_dbg("Barter allowance for %s is %s", name, allowed)
    data.allowed = allowed
    local take_items_indx = {}
    for k,v in pairs(take_items) do
        table.insert(take_items_indx, v)
    end
    data.take_items = take_items_indx

    return data
end

local clr_g  = utils_xml.get_color("d_green")
local clr_r  = utils_xml.get_color("d_red")
local clr_1  = utils_xml.get_color("ui_gray_2")
local clr_2  = utils_xml.get_color("ui_gray_1")
function build_string(name)
    local str = ""
    local funcs = ini_barters:r_string_ex(name, "precond_text") or "barter_core.str_std"
    funcs = str_explode(funcs, ",")
    table.sort(funcs)
    for k,v in pairs(funcs) do
        val = eval_func(v, name)
        if val then
            if type(val) ~= "table" then val = {val} end
            for k,v in pairs(val) do
                str = str .. " " .. gc("st_dot") .. " " .. v .. " \\n"
            end
        end
    end
    return str
end

function safe_insert(tbl, itm) 
    if itm then table.insert(tbl, itm) end
end

function str_any(name)
    if barters[name].type == "anyOf" then
        return gc("st_barter_anyOf")
    end
end

function str_limit(name)
    local rep = ini_barters:r_string_ex(name, "repeat")
    if rep then
        local b_done = barter_mdata[rep][name] or 0
        local b_limit = ini_barters:r_float_ex(name, "limit") or 0
        local clr = b_done < b_limit and clr_g or clr_r
        return gc("st_barter_limit") .. clr ..  " " ..b_done .. "/" .. b_limit .. clr_2 .. " " .. gc("st_barter_"..rep)
    end

end

function str_goodwill(name)
    local faction = ini_barters:r_string_ex(name, "faction")
    local rep = ini_barters:r_float_ex(name, "goodwill") or 0
    if faction and rep > 0 then
        local actor_goodwill = relation_registry.community_goodwill(faction, AC_ID) or 0
        local clr = actor_goodwill < rep and clr_r or clr_g
        return gc(faction) .. " " .. gc("st_barter_goodwill") .. " " .. clr ..  actor_goodwill .. "/" .. rep .. clr_2
    end
end

function str_mutant(name)
    local count = ini_barters:r_float_ex(name, "kill_cnt")
    if count then
        local current = game_statistics.get_statistic_count("killed_monsters") or 0
        local clr = current < count and clr_r or clr_g
        return gc("st_mutants_killed") .. " " .. clr ..  current .. "/" .. count .. clr_2
    end
end

function str_std(name)
    local str = {}
    
    if ini_barters:r_string_ex(name, "repeat") then
        safe_insert(str, str_limit(name))
    end
    if ini_barters:r_string_ex(name, "faction") then
        safe_insert(str, str_goodwill(name))
    end
    
    if ini_barters:r_string_ex(name, "has_info") then
        safe_insert(str, gc("st_barter_info"))
    end

    if barters[name].type == "anyOf" then
        safe_insert(str, gc("st_barter_anyOf"))
    else
        safe_insert(str, gc("st_barter_allOf"))
    end

    return str
end

local function str_toolkit(lv)
    return gc("st_barter_toolkit"..lv)
end

function str_toolkit1(name)
    return str_toolkit(1)
end
function str_toolkit2(name)
    return str_toolkit(2)
end
function str_toolkit3(name)
    return str_toolkit(3)
end

local function remove(item)
    if item.sec == "money" then
        db.actor:give_money(-1 * item.limit)
    else
        local limit = item.limit
        print_dbg("Taking %s of item %s", item.limit, item.sec)
        for i=1,#item.ids do
            if IsItem("multiuse", item.sec) then
                local obj = level.object_by_id(item.ids[i])
                local to_discharge = clamp(limit, 0, obj:get_remaining_uses())
                limit = limit - to_discharge
                utils_item.discharge(obj, to_discharge)
            else
                alife_release_id(item.ids[i])
            end
        end
    end
end

-- assume that the player has filled their end of the bargain and wants to execute on the bargain
function do_barter(name, give, items, ind)
    print_dbg("Performing barter %s, index %s", name, ind)
    if ind and barters[name].type == "anyOf" then
        remove(items[ind])
    else
        for k,v in pairs(items) do
            remove(v)
        end
    end
    if IsItem("multiuse", give.sec) then
        local max_uses = SYS_GetParam(2, give.sec, "max_uses")
        local count = give.amt or max_uses
        while count > 0 do
            local uses = clamp(count, 0, max_uses)
            alife_create_item(give.sec, db.actor, {["uses"] = uses})
            count = clamp(count - max_uses, 0, count)
        end
    else
        local amt = give.amt or 1
        for i=1,amt do
            local meta = {}
            if give.type then
                meta[give.type] = give.meta
            end
            alife_create_item(give.sec, db.actor, meta)
        end
    end
    eval_barter(name, "postcondition")
end

function get_barter_amt(name)
    local rep = ini_barters:r_string_ex(name, "repeat")
    if not rep then return end
    print_dbg("Barter refresh type is %s", rep)
    local barter_sub = rep == "fixed" and barter_mdata.fixed or barter_mdata.restock
    if not barter_sub[name] then barter_sub[name] = 0 end
    return barter_sub[name]
end

function get_give_str(give)
    str = ui_item.get_sec_name(give.sec)
    if give.type then
        str = str .. ", " ..  gc("st_barter_"..give.type) ..give.meta .. " "
        -- pluralize later
    end
    if give.amt > 1 then
        str = str .. " (x" .. give.amt .. ")"
    end
    return str
end

-- barter condition functions
-- return true if barter is allowed (before even checking items to take)

-- check against rep level
function check_goodwill(name)
    -- return true
    local faction = ini_barters:r_string_ex(name, "faction")
    if not faction then return true end
    faction = str_explode(faction, ",")
    local rep = ini_barters:r_float_ex(name, "goodwill") or 0
    for i,fac in pairs(faction) do
        if relation_registry.community_goodwill(fac, AC_ID) < rep then return false end
    end
    return true
end

-- function check_supply_lv(name)
--     local trade_lv = ini_barters:r_string_ex(name, "supply_lvl")
--     if not trade_lv then return true end
--     local npc = mob_trade.GetTalkingNpc()
--     local lv = trader_autoinject.supply_level(npc, true)
--     return lv >= trade_lv
-- end

-- check against limit with variable refresh rate
function check_limit(name)
    if not barter_mdata.fixed then barter_mdata.fixed = {} end
    if not barter_mdata.restock then barter_mdata.restock = {} end
    local barter_amt = get_barter_amt(name)
    if not barter_amt then return end

    local limit = barters[name].limit--ini_barters:r_float_ex(name, "limit")
    return barter_amt < limit
end

function check_info(name)
    local info = ini_barters:r_string_ex(name, "has_info")
    if info then info = str_explode(info, ",") 
    else return true end
    for i,v in pairs(info) do
        if not db.actor:has_info(v) then return false end
    end
    return true
end

-- check all basic preconds
function pre_std(name)
    if ini_barters:r_string_ex(name, "repeat") and not check_limit(name) then return false end
    if ini_barters:r_string_ex(name, "faction") and not check_goodwill(name) then return false end
    if ini_barters:r_string_ex(name, "has_info") and not check_info(name) then return false end
    return true
end

function kill_mutant(name)
    local count = ini_barters:r_float_ex(name, "kill_cnt")
    if count then
        local current = game_statistics.get_statistic_count("killed_monsters") or 0
        return current >= count
    end
end

local function check_toolkit(lv)
    local npc = mob_trade.GetTalkingNpc()
    return has_alife_info(npc:section() .. "_upgrade_tier_" .. tostring(lv))
end

function check_toolkit1(name)
    return check_toolkit(1)
end
function check_toolkit2(name)
    return check_toolkit(2)
end
function check_toolkit3(name)
    return check_toolkit(3)
end
-- allow
function check_pass(name)
    return true
end

-- postconds
function increment_limit(name)
    local rep = ini_barters:r_string_ex(name, "repeat")
    if not rep then return end
    
    if not barter_mdata.fixed then barter_mdata.fixed = {} end
    if not barter_mdata.restock then barter_mdata.restock = {} end

    local limit = ini_barters:r_float_ex(name, "limit") or 0
    local barter_sub = rep == "fixed" and barter_mdata.fixed or barter_mdata.restock
    if not barter_sub[name] then barter_sub[name] = 1
    else
        barter_sub[name] = clamp(barter_sub[name] + 1, 0, limit)
    end
end

function give_info(name)
    local info = ini_barters:r_string_ex(name, "give_info")
    if not info then return end
    db.actor:give_info_portion(info)
end

function post_std(name)
    if ini_barters:r_string_ex(name, "repeat") then increment_limit(name) end
    if ini_barters:r_string_ex(name, "give_info") then give_info(name) end
end

function trader_on_restock(npc)
    local sec = npc:section()
    if not trader_to_barter[sec] then return end
    
    if not barter_mdata.fixed then barter_mdata.fixed = {} end
    if not barter_mdata.restock then barter_mdata.restock = {} end
    if not barter_mdata.give_items then barter_mdata.give_items = {} end
    
    for k,v in pairs(trader_to_barter[sec]) do
        if barter_mdata.restock[v] then
            -- also rotate items
            barter_mdata.restock[v] = 0
        end
        barter_mdata.give_items[v] = false
    end
end

local function parse_barterstring(str)
    local temp = str_explode(str, ",")
    local t = {}
    for k,v in pairs(temp) do
        local group = str_explode(v, ":")
        local item = group[1]
        local uses = group[2]
        if not uses or uses == "full" then
            if IsItem("multiuse", item) then uses = IsItem("multiuse", item) 
            else uses = 1 end
        end
        t[item] = tonumber(uses)
    end
    return t
end

function check_addon(addon)
    if not addon then return true end
    if addon:sub(1, 1) == "!" then
        return not _G[addon:sub(2)]
    else
        return _G[addon]
    end
end

function get_give_item(name)
    local to_give = ini_barters:r_string_ex(name, "give")
    to_give = str_explode(to_give, ",")
    local give
    if #to_give > 1 then
        -- search up cached if exists, select and cache if not
        if not barter_mdata.give_items then barter_mdata.give_items = {} end
        if not barter_mdata.give_items[name] then barter_mdata.give_items[name] = to_give[math.random(#to_give)] end
        give = barter_mdata.give_items[name] 
    else
        give = to_give[1]
    end
    give = str_explode(give, ":")
    give_t = {
        sec = give[1]
    }
    if IsItem("multiuse", give_t.sec) then
        give_t.amt = tonumber(give[2]) or SYS_GetParam(2, give_t.sec, "max_uses")
    else
        give_t.amt = tonumber(give[2]) or 1
    end
    local meta = ini_barters:r_float_ex(name, "give_meta")
    if meta then
        give_t.meta = meta
        if IsItem("ammo", give_t.sec) and give_t.meta <= SYS_GetParam(2, give_t.sec, "box_size") then
            give_t.type = "ammo"
        elseif (IsItem("outfit", give_t.sec) or IsItem("helmet", give_t.sec) or (string.find(give_t.sec, "wpn_") and not IsItem("fake_ammo_wpn", give_t.sec))) and give_t.meta <= 100 then
            give_t.type = "cond"
        end
    end
    return give_t
end

-- cycle through all barters and load only valid ones in
local function validate_barters()
    ini_barters:section_for_each(function(name)
        print_dbg("Parsing barter %s", name)
        local npc = ini_barters:r_string_ex(name, "trader")
        local give = ini_barters:r_string_ex(name, "give")
        local addon = ini_barters:r_string_ex(name, "addon")
        if not check_addon(addon) then 
            print_dbg("Barter %s failed check for addon %s", name, addon)
            return
         end
        if not give then 
            print_dbg("Barter %s has no give item", name)
            return 
        end
        give = str_explode(give, ",")
        -- validate each item
        for k,v in pairs(give) do
            g = str_explode(v, ":")
            if not g[1] or (g[1] ~= "money" and not ini_sys:section_exist(g[1])) then 
                print_dbg("Barter %s attempted to add nonexistant give item %s", name, g[1])
                return false
            end
        end
        
        local take = ini_barters:r_string_ex(name, "take")
        if not take then 
            print_dbg("Barter %s has no take items", name)
            return 
        end
        take = parse_barterstring(take)
        for k,v in pairs(take) do
            if (k ~= "money" and not ini_sys:section_exist(k)) then
                print_dbg("Barter %s attempted to add nonexistant take item %s", name, k)
                return
            end
        end
        local data = {
            -- give = give_t,
            take = take,
        }
        local restricted = ini_barters:r_string_ex(name, "restricted")
        if restricted then
            restricted = str_explode(restricted, ",")
            data.restricted = t2k_table(restricted)
        end

        data.type = ini_barters:r_string_ex(name, "type") or "allOf"
        data.limit = ini_barters:r_float_ex(name, "limit")

        if not trader_to_barter[npc] then trader_to_barter[npc] = {} end
        table.insert(trader_to_barter[npc], name)
        barters[name] = data
    end)
end

local function save_state(mdata) 
	mdata.barter_mdata = barter_mdata
end

local function load_state(mdata) 
	barter_mdata = mdata.barter_mdata or {}
end



function on_game_start()
    RegisterScriptCallback("save_state",save_state)
    RegisterScriptCallback("load_state",load_state)
    RegisterScriptCallback("actor_on_first_update", actor_on_first_update)
    RegisterScriptCallback("trader_on_restock", trader_on_restock)
    validate_barters()
end