local table = require("__flib__.table")
require("scripts.global_init")

return {
    ["1.0.4"] = function()
        log("Running 1.0.4 migration")

        -- delayed_chat_message became a table
        if global.delayed_chat_message == nil then
            global.delayed_chat_messages = {}
        else
            global.delayed_chat_messages = {global.delayed_chat_message}
            global.delayed_chat_message = nil
        end

        -- GUI changed and new outer_table global was added
        for _, player in pairs(game.players) do
            player.gui.screen.clear()
            initialize_player(player)
        end
    end,

    ["1.0.7"] = function()
        log("Running 1.0.7 migration")
        -- 1.0.4 migration contained an error that would affect multiplayer games
        -- Recreate it for all players
        for _, player in pairs(game.players) do
            player.gui.screen.clear()
            initialize_player(player)
        end
    end,

    ["1.0.9"] = function()
        log("Running 1.0.9 migration")
        for force_name, global_force in pairs(global.forces) do
            local affected = false
            for _, milestone in pairs(global_force.complete_milestones) do
                if milestone.type == "technology" and milestone.completion_tick ==
                    nil then
                    affected = true
                    milestone.lower_bound_tick = 0
                    milestone.completion_tick = game.tick
                end
            end

            if affected then
                local force = game.forces[force_name]
                force.print(
                    "[img=milestones_main_icon_white] If you see this message, you were affected by a Milestones bug which lost the completion time of your [font=default-large-bold]technology[/font] milestones.")
                force.print(
                    "The issue is now fixed but you will need to re-enter your lost times in the Milestones window.")
                refresh_gui_for_force(force)
            end
        end
    end,

    ["1.0.10"] = function()
        log("Running 1.0.10 migration")
        -- Editing settings would cause global.loaded_milestones to share objects with global.forces[].*
        -- This could cause global.loaded_milestones to gain completion_tick fields, later messing with initialize_force code
        global.loaded_milestones = table.deep_copy(global.loaded_milestones)
        for _, milestone in pairs(global.loaded_milestones) do
            milestone.completion_tick = nil
            milestone.lower_bound_tick = nil
        end
        for _, global_force in pairs(global.forces) do
            for _, milestone in pairs(global_force.incomplete_milestones) do
                milestone.completion_tick = nil
                milestone.lower_bound_tick = nil
            end
        end
    end,

    ["1.2.1"] = function()
        log("Running 1.2.1 migration")
        -- Table reference error could have introduced completion times in global.loaded_milestones during merge_new_milestones
        global.loaded_milestones = table.deep_copy(global.loaded_milestones)
        for _, milestone in pairs(global.loaded_milestones) do
            milestone.completion_tick = nil
            milestone.lower_bound_tick = nil
        end
    end,

    ["1.3.0"] = function()
        log("Running 1.3.0 migration")
        for force_name, global_force in pairs(global.forces) do
            -- Add new milestones_by_group field, but just put all existing milestones in the Other group
            global_force.milestones_by_group = { ["Other"] = {} }
            for i, milestone in pairs(global_force.complete_milestones) do
                milestone.sort_index = i
                milestone.group = "Other"
                table.insert(global_force.milestones_by_group["Other"], milestone)
            end
            for i, milestone in pairs(global_force.incomplete_milestones) do
                milestone.sort_index = i
                milestone.group = "Other"
                table.insert(global_force.milestones_by_group["Other"], milestone)
            end

            -- Update old estimations with new more accurate estimations
            local force = game.forces[force_name]
            local item_stats = force.item_production_statistics
            local fluid_stats = force.fluid_production_statistics
            local kill_stats = force.kill_count_statistics
            for _, milestone in pairs(global_force.complete_milestones) do
                if is_valid_milestone(milestone) and milestone.lower_bound_tick ~= nil then
                    local new_lower_bound, new_upper_bound = find_completion_tick_bounds(milestone, item_stats, fluid_stats, kill_stats)
                    log("Old tick bounds for " ..milestone.name.. " : " ..milestone.lower_bound_tick.. " - " ..milestone.completion_tick)
                    log("New tick bounds for " ..milestone.name.. " : " ..new_lower_bound.. " - " ..new_upper_bound)
                    milestone.lower_bound_tick = math.max(milestone.lower_bound_tick, new_lower_bound)
                    milestone.completion_tick = math.min(milestone.completion_tick, new_upper_bound)
                end
            end
        end
    end,

    ["1.3.8"] = function()
        log("Running 1.3.8 migration")
        initialize_alias_table()
    end,

    ["1.3.10"] = function()
        log("Running 1.3.10 migration")
        -- inner frame GUI changes, we must recreate GUIs
        for _, player in pairs(game.players) do
            if global.players[player.index] then
                reinitialize_player(player.index)
            end
        end
    end,

    ["1.3.14"] = function()
        log("Running 1.3.14 migration")
        -- Caching some calculations for optimisation
        global.milestones_check_frequency_setting = settings.global["milestones_check_frequency"].value
        for force_name, global_force in pairs(global.forces) do
            local force = game.forces[force_name]
            global_force.item_stats = force.item_production_statistics
            global_force.fluid_stats = force.fluid_production_statistics
            global_force.kill_stats = force.kill_count_statistics
        end
    end,

    ["1.3.20"] = function()
        log("Running 1.3.20 migration")
        -- Recalculate the sort_index of infinite milestones (first is n, second is n.0001, third is n.0002, etc.)
        for force_name, force in pairs(game.forces) do
            if global.forces[force_name] ~= nil then
                merge_new_milestones(force_name, global.loaded_milestones)
                backfill_completion_times(force)
            end
        end
    end,
}