local S = minetest.get_translator 'hudbars'
local NS = function(s)
    return s
end

-- Boilerplate for compatibiliity with pre-5.9.0
-- versions of minetest
local hud_def_type_field
if minetest.features.hud_def_type_field then
    hud_def_type_field = 'type'
else
    hud_def_type_field = 'hud_elem_type'
end

hb = {}

hb.hudtables = {}

-- number of registered HUD bars
hb.hudbars_count = 0

-- table which records which HUD bar slots have been “registered” so far; used for automatic positioning
hb.registered_slots = {}

hb.settings = {}

function hb.load_setting(sname, stype, defaultval, valid_values)
    local sval
    if stype == 'string' then
        sval = minetest.settings:get(sname)
    elseif stype == 'bool' then
        sval = minetest.settings:get_bool(sname)
    elseif stype == 'number' then
        sval = tonumber(minetest.settings:get(sname))
    end
    if sval ~= nil then
        if valid_values ~= nil then
            local valid = false
            for i = 1, #valid_values do
                if sval == valid_values[i] then valid = true end
            end
            if not valid then
                minetest.log(
                    'error',
                    '[hudbars] Invalid value for ' .. sname .. '! Using default value (' .. tostring(defaultval) .. ').'
                )
                return defaultval
            else
                return sval
            end
        else
            return sval
        end
    else
        return defaultval
    end
end

-- Load default settings
dofile(minetest.get_modpath 'hudbars' .. '/default_settings.lua')

local function player_exists(player)
    return player ~= nil and player:is_player()
end

local function make_label(format_string, format_string_config, label, start_value, max_value)
    if hb.settings.hide_labels then return '' end

    local params = {}
    local order = format_string_config.order
    for o = 1, #order do
        if order[o] == 'label' then
            table.insert(params, label)
        elseif order[o] == 'value' then
            if format_string_config.format_value then
                table.insert(params, string.format(format_string_config.format_value, start_value))
            else
                table.insert(params, start_value)
            end
        elseif order[o] == 'max_value' then
            if format_string_config.format_max_value then
                table.insert(params, string.format(format_string_config.format_max_value, max_value))
            else
                table.insert(params, max_value)
            end
        end
    end
    local ret
    if format_string_config.textdomain and minetest.translate then
        ret = minetest.translate(format_string_config.textdomain, format_string, unpack(params))
    else
        ret = S(format_string, unpack(params))
    end
    return ret
end

-- Table which contains all players with active default HUD bars (only for internal use)
hb.players = {}

function hb.value_to_barlength(value, max)
    if max == 0 then
        return 0
    else
        if hb.settings.bar_type == 'progress_bar' then
            local x
            if value < 0 then
                x = -0.5
            else
                x = 0.5
            end
            local ret = math.modf((value / max) * hb.settings.max_bar_length + x)
            return ret
        else
            local x
            if value < 0 then
                x = -0.5
            else
                x = 0.5
            end
            local ret = math.modf((value / max) * hb.settings.statbar_length + x)
            return ret
        end
    end
end

function hb.get_hudtable(identifier)
    return hb.hudtables[identifier]
end

function hb.get_hudbar_position_index(identifier)
    if hb.settings.sorting[identifier] ~= nil then
        return hb.settings.sorting[identifier]
    else
        local i = 0
        while true do
            if hb.registered_slots[i] ~= true and hb.settings.sorting_reverse[i] == nil then return i end
            i = i + 1
        end
    end
end

function hb.register_hudbar(
    identifier,
    text_color,
    label,
    textures,
    default_start_value,
    default_start_max,
    default_start_hidden,
    format_string,
    format_string_config
)
    minetest.log('action', 'hb.register_hudbar: ' .. tostring(identifier))
    local hudtable = {}
    local pos, offset
    local index = math.floor(hb.get_hudbar_position_index(identifier))
    hb.registered_slots[index] = true
    if hb.settings.alignment_pattern == 'stack_up' then
        pos = hb.settings.pos_left
        offset = {
            x = hb.settings.start_offset_left.x,
            y = hb.settings.start_offset_left.y - hb.settings.vmargin * index,
        }
    elseif hb.settings.alignment_pattern == 'stack_down' then
        pos = hb.settings.pos_left
        offset = {
            x = hb.settings.start_offset_left.x,
            y = hb.settings.start_offset_left.y + hb.settings.vmargin * index,
        }
    else
        if index % 2 == 0 then
            pos = hb.settings.pos_left
            offset = {
                x = hb.settings.start_offset_left.x,
                y = hb.settings.start_offset_left.y - hb.settings.vmargin * (index / 2),
            }
        else
            pos = hb.settings.pos_right
            offset = {
                x = hb.settings.start_offset_right.x,
                y = hb.settings.start_offset_right.y - hb.settings.vmargin * ((index - 1) / 2),
            }
        end
    end
    if format_string == nil then format_string = NS '@1: @2/@3' end
    if format_string_config == nil then format_string_config = {} end
    if format_string_config.order == nil then format_string_config.order = { 'label', 'value', 'max_value' } end
    if format_string_config.format_value == nil then format_string_config.format_value = '%d' end
    if format_string_config.format_max_value == nil then format_string_config.format_max_value = '%d' end

    hudtable.add_all = function(player, hudtable, start_value, start_max, start_hidden)
        if start_value == nil then start_value = hudtable.default_start_value end
        if start_max == nil then start_max = hudtable.default_start_max end
        if start_hidden == nil then start_hidden = hudtable.default_start_hidden end
        local ids = {}
        local state = {}
        local name = player:get_player_name()
        local bgscale, iconscale, text, barnumber, bgiconnumber
        if start_max == 0 or start_hidden then
            bgscale = { x = 0, y = 0 }
        else
            bgscale = { x = 1, y = 1 }
        end
        if start_hidden then
            iconscale = { x = 0, y = 0 }
            barnumber = 0
            bgiconnumber = 0
            text = ''
        else
            iconscale = { x = 1, y = 1 }
            barnumber = hb.value_to_barlength(start_value, start_max)
            bgiconnumber = hb.settings.statbar_length
            text = make_label(format_string, format_string_config, label, start_value, start_max)
        end
        if hb.settings.bar_type == 'progress_bar' then
            ids.bg = player:hud_add {
                [hud_def_type_field] = 'image',
                position = pos,
                scale = bgscale,
                text = 'hudbars_bar_background.png',
                alignment = { x = 1, y = 1 },
                offset = { x = offset.x - 1, y = offset.y - 1 },
                z_index = 0,
            }
            if textures.icon ~= nil then
                ids.icon = player:hud_add {
                    [hud_def_type_field] = 'image',
                    position = pos,
                    scale = iconscale,
                    text = textures.icon,
                    alignment = { x = -1, y = 1 },
                    offset = { x = offset.x - 3, y = offset.y },
                    z_index = 1,
                }
            end
        end
        local bar_image, bgicon, bar_size
        if hb.settings.bar_type == 'progress_bar' then
            bar_image = textures.bar
            -- NOTE: Intentionally set to nil. For some reason, on some systems,
            -- the progress bar is displaced when the bar_size is set explicitly here.
            -- On the other hand, setting this to nil is deprecated in MT 5.0.0 due to
            -- a debug log warning, but nothing is explained in lua_api.txt.
            -- This section is a potential bug magnet, please watch with care!
            -- The size of the bar image is expected to be exactly 2×16 pixels.
            bar_size = nil
        elseif hb.settings.bar_type == 'statbar_classic' or hb.settings.bar_type == 'statbar_modern' then
            bar_image = textures.icon
            bgicon = textures.bgicon
            bar_size = { x = 24, y = 24 }
        end
        ids.bar = player:hud_add {
            [hud_def_type_field] = 'statbar',
            position = pos,
            text = bar_image,
            text2 = bgicon,
            number = barnumber,
            item = bgiconnumber,
            alignment = { x = -1, y = -1 },
            offset = offset,
            direction = 0,
            size = bar_size,
            z_index = 1,
        }
        if hb.settings.bar_type == 'progress_bar' then
            ids.text = player:hud_add {
                [hud_def_type_field] = 'text',
                position = pos,
                text = text,
                alignment = { x = 1, y = 1 },
                number = text_color,
                direction = 0,
                offset = { x = offset.x + 2, y = offset.y - 1 },
                z_index = 2,
            }
        end
        -- Do not forget to update hb.get_hudbar_state if you add new fields to the state table
        state.hidden = start_hidden
        state.value = start_value
        state.max = start_max
        state.text = text
        state.barlength = hb.value_to_barlength(start_value, start_max)

        local main_error_text = '[hudbars] Bad initial values of HUD bar identifier “'
            .. tostring(identifier)
            .. '” for player '
            .. name
            .. '. '

        if start_max < start_value then
            minetest.log(
                'error',
                main_error_text
                    .. 'start_max ('
                    .. start_max
                    .. ') is smaller than start_value ('
                    .. start_value
                    .. ')!'
            )
        end
        if start_max < 0 then
            minetest.log('error', main_error_text .. 'start_max (' .. start_max .. ') is smaller than 0!')
        end
        if start_value < 0 then
            minetest.log('error', main_error_text .. 'start_value (' .. start_value .. ') is smaller than 0!')
        end

        hb.hudtables[identifier].hudids[name] = ids
        hb.hudtables[identifier].hudstate[name] = state
    end

    hudtable.identifier = identifier
    hudtable.format_string = format_string
    hudtable.format_string_config = format_string_config
    hudtable.label = label
    hudtable.hudids = {}
    hudtable.hudstate = {}
    hudtable.default_start_hidden = default_start_hidden
    hudtable.default_start_value = default_start_value
    hudtable.default_start_max = default_start_max

    hb.hudbars_count = hb.hudbars_count + 1

    hb.hudtables[identifier] = hudtable
end

function hb.init_hudbar(player, identifier, start_value, start_max, start_hidden)
    if not player_exists(player) then return false end
    local hudtable = hb.get_hudtable(identifier)
    hb.hudtables[identifier].add_all(player, hudtable, start_value, start_max, start_hidden)
    return true
end

function hb.change_hudbar(
    player,
    identifier,
    new_value,
    new_max_value,
    new_icon,
    new_bgicon,
    new_bar,
    new_label,
    new_text_color
)
    if
        new_value == nil
        and new_max_value == nil
        and new_icon == nil
        and new_bgicon == nil
        and new_bar == nil
        and new_label == nil
        and new_text_color == nil
    then
        return true
    end
    if not player_exists(player) then return false end

    local name = player:get_player_name()
    local hudtable = hb.get_hudtable(identifier)
    if not hudtable.hudstate[name] then return false end
    local value_changed, max_changed = false, false

    if new_value ~= nil then
        if new_value ~= hudtable.hudstate[name].value then
            hudtable.hudstate[name].value = new_value
            value_changed = true
        end
    else
        new_value = hudtable.hudstate[name].value
    end
    if new_max_value ~= nil then
        if new_max_value ~= hudtable.hudstate[name].max then
            hudtable.hudstate[name].max = new_max_value
            max_changed = true
        end
    else
        new_max_value = hudtable.hudstate[name].max
    end

    if hb.settings.bar_type == 'progress_bar' then
        if new_icon ~= nil and hudtable.hudids[name].icon ~= nil then
            player:hud_change(hudtable.hudids[name].icon, 'text', new_icon)
        end
        if new_bgicon ~= nil and hudtable.hudids[name].bgicon ~= nil then
            player:hud_change(hudtable.hudids[name].bgicon, 'text', new_bgicon)
        end
        if new_bar ~= nil then player:hud_change(hudtable.hudids[name].bar, 'text', new_bar) end
        if new_label ~= nil then
            hudtable.label = new_label
            local new_text = make_label(
                hudtable.format_string,
                hudtable.format_string_config,
                new_label,
                hudtable.hudstate[name].value,
                hudtable.hudstate[name].max
            )
            player:hud_change(hudtable.hudids[name].text, 'text', new_text)
        end
        if new_text_color ~= nil then player:hud_change(hudtable.hudids[name].text, 'number', new_text_color) end
    else
        if new_icon ~= nil and hudtable.hudids[name].bar ~= nil then
            player:hud_change(hudtable.hudids[name].bar, 'text', new_icon)
        end
        if new_bgicon ~= nil and hudtable.hudids[name].bg ~= nil then
            player:hud_change(hudtable.hudids[name].bg, 'text', new_bgicon)
        end
    end

    local main_error_text = '[hudbars] Bad call to hb.change_hudbar, identifier: “'
        .. tostring(identifier)
        .. '”, player name: “'
        .. name
        .. '”. '
    if new_max_value < new_value then
        minetest.log(
            'error',
            main_error_text
                .. 'new_max_value ('
                .. new_max_value
                .. ') is smaller than new_value ('
                .. new_value
                .. ')!'
        )
    end
    if new_max_value < 0 then
        minetest.log('error', main_error_text .. 'new_max_value (' .. new_max_value .. ') is smaller than 0!')
    end
    if new_value < 0 then
        minetest.log('error', main_error_text .. 'new_value (' .. new_value .. ') is smaller than 0!')
    end

    if hudtable.hudstate[name].hidden == false then
        if max_changed and hb.settings.bar_type == 'progress_bar' then
            if hudtable.hudstate[name].max == 0 then
                player:hud_change(hudtable.hudids[name].bg, 'scale', { x = 0, y = 0 })
            else
                player:hud_change(hudtable.hudids[name].bg, 'scale', { x = 1, y = 1 })
            end
        end

        if value_changed or max_changed then
            local new_barlength = hb.value_to_barlength(new_value, new_max_value)
            if new_barlength ~= hudtable.hudstate[name].barlength then
                player:hud_change(hudtable.hudids[name].bar, 'number', hb.value_to_barlength(new_value, new_max_value))
                hudtable.hudstate[name].barlength = new_barlength
            end

            if hb.settings.bar_type == 'progress_bar' then
                local new_text = make_label(
                    hudtable.format_string,
                    hudtable.format_string_config,
                    hudtable.label,
                    new_value,
                    new_max_value
                )
                if new_text ~= hudtable.hudstate[name].text then
                    player:hud_change(hudtable.hudids[name].text, 'text', new_text)
                    hudtable.hudstate[name].text = new_text
                end
            end
        end
    end
    return true
end

function hb.hide_hudbar(player, identifier)
    if not player_exists(player) then return false end
    local name = player:get_player_name()
    local hudtable = hb.get_hudtable(identifier)
    if hudtable == nil then return false end
    if hudtable.hudstate[name].hidden == true then return true end
    if hb.settings.bar_type == 'progress_bar' then
        if hudtable.hudids[name].icon ~= nil then
            player:hud_change(hudtable.hudids[name].icon, 'scale', { x = 0, y = 0 })
        end
        player:hud_change(hudtable.hudids[name].bg, 'scale', { x = 0, y = 0 })
        player:hud_change(hudtable.hudids[name].text, 'text', '')
    end
    player:hud_change(hudtable.hudids[name].bar, 'number', 0)
    player:hud_change(hudtable.hudids[name].bar, 'item', 0)
    hudtable.hudstate[name].hidden = true
    return true
end

function hb.unhide_hudbar(player, identifier)
    if not player_exists(player) then return false end
    local name = player:get_player_name()
    local hudtable = hb.get_hudtable(identifier)
    if hudtable == nil then return false end
    if hudtable.hudstate[name].hidden == false then return true end
    local value = hudtable.hudstate[name].value
    local max = hudtable.hudstate[name].max
    if hb.settings.bar_type == 'progress_bar' then
        if hudtable.hudids[name].icon ~= nil then
            player:hud_change(hudtable.hudids[name].icon, 'scale', { x = 1, y = 1 })
        end
        if hudtable.hudstate[name].max ~= 0 then
            player:hud_change(hudtable.hudids[name].bg, 'scale', { x = 1, y = 1 })
        end
        player:hud_change(
            hudtable.hudids[name].text,
            'text',
            make_label(hudtable.format_string, hudtable.format_string_config, hudtable.label, value, max)
        )
    elseif hb.settings.bar_type == 'statbar_modern' then
        player:hud_change(hudtable.hudids[name].bar, 'scale', { x = 1, y = 1 })
    end
    player:hud_change(hudtable.hudids[name].bar, 'number', hb.value_to_barlength(value, max))
    player:hud_change(hudtable.hudids[name].bar, 'item', hb.value_to_barlength(max, max))
    hudtable.hudstate[name].hidden = false
    return true
end

function hb.get_hudbar_state(player, identifier)
    if not player_exists(player) then return nil end
    local ref = hb.get_hudtable(identifier).hudstate[player:get_player_name()]
    if not ref then return nil end
    -- Do not forget to update this chunk of code in case the state changes
    local copy = {
        hidden = ref.hidden,
        value = ref.value,
        max = ref.max,
        text = ref.text,
        barlength = ref.barlength,
    }
    return copy
end

function hb.get_hudbar_identifiers()
    local ids = {}
    for id, _ in pairs(hb.hudtables) do
        table.insert(ids, id)
    end
    return ids
end

--register built-in HUD bars
if minetest.settings:get_bool 'enable_damage' or hb.settings.forceload_default_hudbars then
    hb.register_hudbar(
        'health',
        0xFFFFFF,
        S 'Health',
        { bar = 'hudbars_bar_health.png', icon = 'hudbars_icon_health.png', bgicon = 'hudbars_bgicon_health.png' },
        20,
        20,
        false
    )
    hb.register_hudbar(
        'breath',
        0xFFFFFF,
        S 'Breath',
        { bar = 'hudbars_bar_breath.png', icon = 'hudbars_icon_breath.png', bgicon = 'hudbars_bgicon_breath.png' },
        10,
        10,
        true
    )
end

local function hide_builtin(player)
    local flags = player:hud_get_flags()
    flags.healthbar = false
    flags.breathbar = false
    player:hud_set_flags(flags)
end

local function custom_hud(player)
    if minetest.settings:get_bool 'enable_damage' or hb.settings.forceload_default_hudbars then
        local hide
        if minetest.settings:get_bool 'enable_damage' then
            hide = false
        else
            hide = true
        end
        local hp = player:get_hp()
        local hp_max = player:get_properties().hp_max
        hb.init_hudbar(player, 'health', math.min(hp, hp_max), hp_max, hide)
        local breath = player:get_breath()
        local breath_max = player:get_properties().breath_max
        local hide_breath
        if breath >= breath_max and hb.settings.autohide_breath == true then
            hide_breath = true
        else
            hide_breath = false
        end
        hb.init_hudbar(player, 'breath', math.min(breath, breath_max), breath_max, hide_breath or hide)
    end
end

local function update_health(player)
    local hp_max = player:get_properties().hp_max
    local hp = math.min(player:get_hp(), hp_max)
    if hp >= hp_max and player:get_meta():get_int 'no_autohide_hp' == 0 then
        hb.hide_hudbar(player, 'health')
    else
        hb.unhide_hudbar(player, 'health')
        hb.change_hudbar(player, 'health', hp, hp_max)
    end
end

-- update built-in HUD bars
local function update_hud(player)
    if not player_exists(player) then return end
    if minetest.settings:get_bool 'enable_damage' then
        if hb.settings.forceload_default_hudbars then hb.unhide_hudbar(player, 'health') end
        local breath_max = player:get_properties().breath_max

        local breath = player:get_breath()

        if breath >= breath_max and hb.settings.autohide_breath == true then
            hb.hide_hudbar(player, 'breath')
        else
            hb.unhide_hudbar(player, 'breath')
            hb.change_hudbar(player, 'breath', math.min(breath, breath_max), breath_max)
        end
        --health
        update_health(player)
    elseif hb.settings.forceload_default_hudbars then
        hb.hide_hudbar(player, 'health')
        hb.hide_hudbar(player, 'breath')
    end
end

minetest.register_on_player_hpchange(function(player)
    if hb.players[player:get_player_name()] ~= nil then update_health(player) end
end)

minetest.register_on_respawnplayer(function(player)
    update_health(player)
    hb.hide_hudbar(player, 'breath')
end)

minetest.register_on_joinplayer(function(player)
    hide_builtin(player)
    custom_hud(player)
    hb.players[player:get_player_name()] = player
end)

minetest.register_on_leaveplayer(function(player)
    hb.players[player:get_player_name()] = nil
end)

local main_timer = 0
local timer = 0
minetest.register_globalstep(function(dtime)
    main_timer = main_timer + dtime
    timer = timer + dtime
    if main_timer > hb.settings.tick or timer > 4 then
        if main_timer > hb.settings.tick then main_timer = 0 end
        -- only proceed if damage is enabled
        if minetest.settings:get_bool 'enable_damage' or hb.settings.forceload_default_hudbars then
            for _, player in pairs(hb.players) do
                -- update all hud elements
                update_hud(player)
            end
        end
    end
    if timer > 4 then timer = 0 end
end)
