local Report = require 'features.report'
local UserGroups = require 'features.user_groups'
local Game = require 'utils.game'
local Server = require 'features.server'
local Timestamp = require 'utils.timestamp'
local Command = require 'utils.command'

local format = string.format
local ceil = math.ceil

--- Kill a player with fish as the cause of death.
local function do_fish_kill(player, suicide)
    local c = player.character
    if not c then
        return false
    end

    local e = player.surface.create_entity {name = 'fish', position = player.position}
    c.die(player.force, e)

    -- Don't want people killing themselves for free fish.
    if suicide then
        e.destroy()
    end

    return true
end

--- Kill a player: admins and the server can kill others, non-admins can only kill themselves
local function kill(args, player)
    local target_name = args.player
    local target
    if target_name then
        target = game.players[target_name]
        if not target then
            Game.player_print(format('Player %s was not found.', target_name))
            return
        end
    end

    if global.walking and ((player and global.walking[player.index]) or (target and global.walking[target.index])) then
        Game.player_print("A player on walkabout cannot be killed by a mere fish, don't waste your efforts.")
        return
    end

    if not target and player then
        if not do_fish_kill(player, true) then
            Game.player_print("Sorry, you don't have a character to kill.")
        end
    elseif player then
        if target == player then
            if not do_fish_kill(player, true) then
                Game.player_print("Sorry, you don't have a character to kill.")
            end
        elseif target and player.admin then
            if not do_fish_kill(target) then
                Game.player_print(table.concat {"'Sorry, '", target.name, "' doesn't have a character to kill."})
            end
        else
            Game.player_print("Sorry you don't have permission to use the kill command on other players.")
        end
    elseif target then
        if not do_fish_kill(target) then
            Game.player_print(table.concat {"'Sorry, '", target.name, "' doesn't have a character to kill."})
        end
    end
end

--- Check players' afk times
local function afk()
    local count = 0
    for _, v in pairs(game.players) do
        if v.afk_time > 300 then
            count = count + 1
            local time = ' '
            if v.afk_time > 21600 then
                time = time .. math.floor(v.afk_time / 216000) .. ' hours '
            end
            if v.afk_time > 3600 then
                time = time .. math.floor(v.afk_time / 3600) % 60 .. ' minutes and '
            end
            time = time .. math.floor(v.afk_time / 60) % 60 .. ' seconds.'
            Game.player_print(v.name .. ' has been afk for' .. time)
        end
    end
    if count == 0 then
        Game.player_print('No players afk.')
    end
end

--- Lets a player set their zoom level
local function zoom(args, player)
    if tonumber(args.zoom) then
        player.zoom = tonumber(args.zoom)
    else
        Game.player_print('You must give zoom a number.')
    end
end

--- Creates an alert for the player at the location of their target
local function find_player(args, player)
    local name = args.player

    local target = game.players[name]
    if not target then
        Game.player_print('player ' .. name .. ' not found')
        return
    end

    target = target.character
    if not target or not target.valid then
        Game.player_print('player ' .. name .. ' does not have a character')
        return
    end

    player.add_custom_alert(target, {type = 'virtual', name = 'signal-F'}, name, true)
end

--- Turns on rail block visualization for player
local function show_rail_block(_, player)
    local vs = player.game_view_settings
    local show = not vs.show_rail_block_visualisation
    vs.show_rail_block_visualisation = show

    Game.player_print('show_rail_block_visualisation set to ' .. tostring(show))
end

local function server_time(_, player)
    local p
    if not player then
        p = print
    elseif player.valid then
        p = player.print
    else
        return
    end

    local secs = Server.get_current_time()
    if secs == nil then
        p('Server time is not available, is this game running on a Redmew server?')
    else
        p(Timestamp.to_string(secs))
    end
end

local function search_command(arguments)
    local keyword = arguments.keyword
    local p = Game.player_print
    if #keyword < 2 then
        p('Keyword should be 2 characters or more')
        return
    end

    local per_page = 7
    local matches = Command.search(keyword)
    local count = #matches

    if count == 0 then
        p('---- 0 Search Results ----')
        p(format('No commands found matching "%s"', keyword))
        p('-------------------------')
        return
    end

    local page = tonumber(arguments.page)
    local pages = ceil(count / per_page)

    if nil == page then
        p('Page should be a valid number')
        return
    end

    -- just show the last page
    if page > pages then
        page = pages
    end

    if page < 1 then
        page = 1
    end

    local page_start = per_page * (page - 1) + 1
    local page_end = per_page * page
    page_end = page_end <= count and page_end or count

    p(format('---- %d Search %s -----', count, count == 1 and 'Result' or 'Results'))
    p(format('Searching for: "%s"', keyword))
    for i = page_start, page_end do
        p(format('[%d] /%s', i, matches[i]))
    end
    p(format('-------- Page %d / %d --------', page, pages))
end

-- Command registrations

Command.add(
    'kill',
    {
        description = 'Will kill you.',
        arguments = {'player'},
        default_values = {player = false},
        allowed_by_server = true,
    },
    kill
)

Command.add(
    'afk',
    {
        description = 'Shows how long players have been afk.',
        allowed_by_server = true,
    },
    afk
)

Command.add(
    'zoom',
    {
        description = 'Sets your zoom.',
        arguments = {'zoom'},
    },
    zoom
)

Command.add(
    'find',
    {
        description = 'shows an alert on the map where the player is located',
        arguments = {'player'},
    },
    find_player
)

Command.add(
    'show-rail-block',
    {
        description = 'Toggles rail block visualisation.',
    },
    show_rail_block
)

Command.add(
    'server-time',
    {
        description = "Prints the server's time.",
        allowed_by_server = true,
    },
    server_time
)

Command.add(
    'search-command',
    {
        description = 'Search for commands matching the keyword in name or description',
        arguments = {'keyword', 'page'},
        default_values = {page = 1},
        allowed_by_server = true,
    },
    search_command
)

-- Commands with no functions, only calls to other modules

Command.add(
    'report',
    {
        description = 'Reports a user to admins',
        arguments = {'player', 'message'},
        capture_excess_arguments = true,
    },
    Report.report_command
)

Command.add(
    'regulars',
    {
        description = 'Prints a list of game regulars.',
        allowed_by_server = true,
    },
    UserGroups.print_regulars
)