--[[-- Core Module - Gui
- Used to define new gui elements and gui event handlers
@module Gui
]]

local Gui = require 'expcore.gui.prototype'
local mod_gui = require 'mod-gui'

local hide_left_flow = Gui.core_defines.hide_left_flow.name

--- Left Flow.
-- @section leftFlow

-- Triggered when a user changed the visibility of a left flow element by clicking a button
Gui.events.on_visibility_changed_by_click = 'on_visibility_changed_by_click'

--- Contains the uids of the elements that will shown on the left flow and their join functions
-- @table left_elements
Gui.left_elements = {}

--[[-- Gets the flow refered to as the left flow, each player has one left flow
@function Gui.get_left_flow(player)
@tparam LuaPlayer player the player that you want to get the left flow for
@treturn LuaGuiElement the left element flow

@usage-- Geting your left flow
local left_flow = Gui.get_left_flow(game.player)

]]
Gui.get_left_flow = mod_gui.get_frame_flow

--[[-- Sets an element define to be drawn to the left flow when a player joins, includes optional check
@tparam[opt] ?boolean|function open_on_join called during first darw to decide if the element should be visible
@treturn table the new element define that is used to register events to this element

@usage-- Adding the example button
example_flow_with_button:add_to_left_flow(true)

]]
function Gui._prototype_element:add_to_left_flow(open_on_join)
    if not self.name then error("Elements for the top flow must have a static name") end
    Gui.left_elements[self] = open_on_join or false
    return self
end

--[[-- Creates a button on the top flow which will toggle the given element define, the define must exist in the left flow
@tparam string sprite the sprite that you want to use on the button
@tparam ?string|Concepts.LocalizedString tooltip the tooltip that you want the button to have
@tparam table element_define the element define that you want to have toggled by this button, define must exist on the left flow
@tparam[opt] function authenticator used to decide if the button should be visible to a player

@usage-- Add a button to toggle a left element
local toolbar_button =
Gui.left_toolbar_button('entity/inserter', 'Nothing to see here', example_flow_with_button, function(player)
    return player.admin
end)

]]
function Gui.left_toolbar_button(sprite, tooltip, element_define, authenticator)
    local button = Gui.toolbar_button(sprite, tooltip, authenticator)

    -- Add on_click handler to handle click events comming from the player
    button:on_click(function(player, _,_)
        local top_flow = Gui.get_top_flow(player)
        local element = top_flow[button.name]
        local visibility_state  = Gui.toggle_left_element(player, element_define)

        -- Raise custom event that tells listening elements if the element has changed visibility by a player clicking
        -- Used in warp gui to handle the keep open logic
        button:raise_custom_event{
            name = Gui.events.on_visibility_changed_by_click,
            element = element,
            state = visibility_state
        }
    end)

    -- Add property to the left flow element with the name of the button
    -- This is for the ability to reverse lookup the button from the left flow element
    element_define.toolbar_button = button.name
    return button
end

--[[-- Draw all the left elements onto the left flow, internal use only with on join
@tparam LuaPlayer player the player that you want to draw the elements for

@usage-- Draw all the left elements
Gui.draw_left_flow(player)

]]
function Gui.draw_left_flow(player)
    local left_flow = Gui.get_left_flow(player)
    local hide_button = left_flow.gui_core_buttons[hide_left_flow]
    local show_hide_button = false

    for element_define, open_on_join in pairs(Gui.left_elements) do
        -- Draw the element to the left flow
        local draw_success, left_element = xpcall(function()
            return element_define(left_flow)
        end, debug.traceback)

        if not draw_success then
            error('There as been an error with an element draw function: '..element_define.defined_at..'\n\t'..left_element)
        end

        -- Check if it should be open by default
        local visible = type(open_on_join) == 'boolean' and open_on_join or false
        if type(open_on_join) == 'function' then
            local success, err = pcall(open_on_join, player)
            if not success then
                error('There as been an error with an open on join hander for a gui element:\n\t'..err)
            end
            visible = err
        end

        -- Set the visible state of the element
        left_element.visible = visible
        show_hide_button = show_hide_button or visible

        -- Get the assosiated element define
        local top_flow = Gui.get_top_flow(player)

        -- Check if the the element has a button attached
        if element_define.toolbar_button then
            -- Check if the topflow contains the button
            local button = top_flow[element_define.toolbar_button]
            if button then
                -- Style the button
                Gui.toolbar_button_style(button, visible)
            end
        end
    end

    hide_button.visible = show_hide_button
end

--[[-- Update the visible state of the hide button, can be used to check if any frames are visible
@tparam LuaPlayer player the player to update the left flow for
@treturn boolean true if any left element is visible

@usage-- Check if any left elements are visible
local visible = Gui.update_left_flow(player)

]]
function Gui.update_left_flow(player)
    local left_flow = Gui.get_left_flow(player)
    local hide_button = left_flow.gui_core_buttons[hide_left_flow]
    for element_define, _ in pairs(Gui.left_elements) do
        local left_element = left_flow[element_define.name]
        if left_element.visible then
            hide_button.visible = true
            return true
        end
    end
    hide_button.visible = false
    return false
end

--[[-- Hides all left elements for a player
@tparam LuaPlayer player the player to hide the elements for

@usage-- Hide your left elements
Gui.hide_left_flow(game.player)

]]
function Gui.hide_left_flow(player)
    local top_flow = Gui.get_top_flow(player)
    local left_flow = Gui.get_left_flow(player)
    local hide_button = left_flow.gui_core_buttons[hide_left_flow]

    -- Set the visible state of all elements in the flow
    hide_button.visible = false
    for element_define, _ in pairs(Gui.left_elements) do
        left_flow[element_define.name].visible = false

        -- Check if the the element has a toobar button attached
        if element_define.toolbar_button then
            -- Check if the topflow contains the button
            local button = top_flow[element_define.toolbar_button]
            if button then
                -- Style the button
                Gui.toolbar_button_style(button, false)
                -- Get the button define from the reverse lookup on the element
                local button_define = Gui.defines[element_define.toolbar_button]
                -- Raise the custom event if all of the top checks have passed
                button_define:raise_custom_event{
                    name = Gui.events.on_visibility_changed_by_click,
                    element = button,
                    state = false
                }
            end
        end
    end
end

--[[-- Get the element define that is in the left flow, use in events without an element refrence
@tparam LuaPlayer player the player that you want to get the element for
@tparam table element_define the element that you want to get
@treturn LuaGuiElement the gui element linked to this define for this player

@usage-- Get your left element
local frame = Gui.get_left_element(game.player, example_flow_with_button)

]]
function Gui.get_left_element(player, element_define)
    local left_flow = Gui.get_left_flow(player)
    return left_flow[element_define.name]
end

--[[-- Toggles the visible state of a left element for a given player, can be used to set the visible state
@tparam LuaPlayer player the player that you want to toggle the element for
@tparam table element_define the element that you want to toggle
@tparam[opt] boolean state with given will set the state, else state will be toggled
@treturn boolean the new visible state of the element

@usage-- Toggle your example button
Gui.toggle_top_flow(game.player, example_flow_with_button)

@usage-- Show your example button
Gui.toggle_top_flow(game.player, example_flow_with_button, true)

]]
function Gui.toggle_left_element(player, element_define, state)
    local left_flow = Gui.get_left_flow(player)
    local top_flow = Gui.get_top_flow(player)

    -- Set the visible state
    local element = left_flow[element_define.name]
    if state == nil then state = not element.visible end
    element.visible = state
    Gui.update_left_flow(player)

    -- Check if the the element has a button attached
    if element_define.toolbar_button then
        -- Check if the topflow contains the button
        local button = top_flow[element_define.toolbar_button]
        if button then
            -- Style the button
            Gui.toolbar_button_style(button, state)
        end
    end
    return state
end