debug_mod_name = "Zoom"
require("utils")

local zoom_factor = 1.5
local zoom_wide_max = 0.01
local zoom_wide_hotkey = 1 / (zoom_factor^7)
local zoom_close_max = 16.00
local player_mem = {}

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local function init_player(player)
    if player_mem == nil then return end

    -- initialize or update per player globals of the mod, and reset the gui
    debug_print( "init_player ", player.name, " connected=", player.connected )

    player_mem[player.index] = player_mem[player.index] or {}

    local player_mem = player_mem[player.index]
    player_mem.player = player_mem.player or player
    player_mem.zoom = player_mem.zoom or 1

    if player.connected then
        build_bar(player)
    end
end

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local function init_players()
    for _, player in pairs(game.players) do
        init_player(player)
    end
end

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local function on_init()
    -- called once, the first time the mod is loaded on a game (new or existing game)
    debug_print( "on_init" )
    init_players()
end

script.on_init(on_init)

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local function on_configuration_changed(data)
    -- detect any mod or game version change
    if data.mod_changes ~= nil then
        local changes = data.mod_changes[debug_mod_name]
        if changes ~= nil then
            debug_print( "update mod: ", debug_mod_name, " ", tostring(changes.old_version), " to ", tostring(changes.new_version) )
            init_players()
        end
    end
end

script.on_configuration_changed(on_configuration_changed)

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local function on_player_created(event)
    -- called at player creation
    local player = game.players[event.player_index]
    debug_print( "player created ", player.name )

    init_player(player)
end

script.on_event(defines.events.on_player_created, on_player_created )

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local function on_player_joined_game(event)
    -- called in SP(once) and MP(at every connect), eventually after on_player_created
    local player = game.players[event.player_index]
    debug_print( "player joined ", player.name )

    init_player(player)
end

script.on_event(defines.events.on_player_joined_game, on_player_joined_game )

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local function on_gui_click(event)
    local player = game.players[event.player_index]
    local event_name = event.element.name
    local prefix = string.sub(event_name,1,14)
    local suffix = string.sub(event_name,15)

    debug_print( "on_gui_click ", player.name, " ", event_name )

    if event_name == "but_zoom_zin" then
        local player_mem = player_mem[player.index]
        if player_mem.zoom < zoom_close_max then
            player_mem.zoom = player_mem.zoom * zoom_factor
            player.zoom = player_mem.zoom
        end

    elseif event_name == "but_zoom_zout" then
        local player_mem = player_mem[player.index]
        if player_mem.zoom > zoom_wide_max then
            player_mem.zoom = player_mem.zoom / zoom_factor
            player.zoom = player_mem.zoom
        end
    end
end

script.on_event(defines.events.on_gui_click, on_gui_click)

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local function on_zoom_hotkey(event)
    local player = game.players[event.player_index]
    local player_mem = player_mem[player.index]
    player_mem.zoom = zoom_wide_hotkey
    player.zoom = player_mem.zoom
end

script.on_event("zoom_hotkey", on_zoom_hotkey)

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function build_bar( player )
    -- here only build gui, but not try to update it with player data that is not always already available (in init_player for example)
    local guif = player.gui.top.flw_zoom

    if guif == nil then
        debug_print("create gui player" .. player.name)
        guif = player.gui.top.add({type = "flow", name = "flw_zoom", direction = "horizontal", style = "zoom_flow_style"})
        guif.add({type = "sprite-button", name = "but_zoom_zout", sprite = "sprite_zout", style = "zoom_sprite_style"})
        guif.add({type = "sprite-button", name = "but_zoom_zin", sprite = "sprite_zin", style = "zoom_sprite_style"})
    end
end

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local interface = {}

function interface.reset()
    debug_print( "reset" )

    for _, player in pairs(game.players) do
        if player.gui.top.flw_zoom then player.gui.top.flw_zoom.destroy() end
        init_player(player)
    end
end

remote.add_interface( "zoom", interface )

-- /c remote.call( "zoom", "reset" )