--!A cross-platform build utility based on Lua
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
--     http://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
--
-- Copyright (C) 2015-present, TBOOX Open Source Group.
--
-- @author      ruki
-- @file        tty.lua
--

-- define module
local tty = tty or {}

-- load modules
local io = require("base/io")

-- @see http://www.termsys.demon.co.uk/vtansi.htm

-- write control characters
function tty._iowrite(...)
    local isatty = tty._ISATTY
    if isatty == nil then
        isatty = io.isatty()
        tty._ISATTY = isatty
    end
    if isatty then
        io.write(...)
    end
end

-- erases from the current cursor position to the end of the current line.
function tty.erase_line_to_end()
    tty._iowrite("\x1b[K")
    return tty
end

-- erases from the current cursor position to the start of the current line.
function tty.erase_line_to_start()
    tty._iowrite("\x1b[1K")
    return tty
end

-- erases the entire current line
function tty.erase_line()
    tty._iowrite("\x1b[2K")
    return tty
end

-- erases the screen from the current line down to the bottom of the screen.
function tty.erase_down()
    tty._iowrite("\x1b[J")
    return tty
end

-- erases the screen from the current line up to the top of the screen.
function tty.erase_up()
    tty._iowrite("\x1b[1J")
    return tty
end

-- erases the screen with the background colour and moves the cursor to home.
function tty.erase_screen()
    tty._iowrite("\x1b[2J")
    return tty
end

-- save current cursor position.
function tty.cursor_save()
    tty._iowrite("\x1b[s")
    return tty
end

-- restores cursor position after a save cursor.
function tty.cursor_restore()
    tty._iowrite("\x1b[u")
    return tty
end

-- save current cursor position and color attrs
function tty.cursor_and_attrs_save()
    tty._iowrite("\x1b7")
    return tty
end

-- restores cursor position and color attrs after a save cursor.
function tty.cursor_and_attrs_restore()
    tty._iowrite("\x1b8")
    return tty
end

-- carriage return
function tty.cr()
    tty._iowrite("\r")
    return tty
end

-- flush control
function tty.flush()
    if io.isatty() then
        io.flush()
    end
    return tty
end

-- get terminal name
--  - xterm
--  - cmd
--  - vstudio (in visual studio)
--  - vscode (in vscode)
--  - msys2
--  - cygwin
--  - powershell
--  - windows-terminal
--  - gnome-terminal
--  - xfce4-terminal
--  - konsole
--  - terminator
--  - rxvt
--  - lxterminal
--  - unknown
--
function tty.term()
    local term = tty._TERM
    if term == nil then

        -- get term from $TERM_PROGRAM
        if term == nil then
            local TERM_PROGRAM = os.getenv("TERM_PROGRAM")
            if TERM_PROGRAM ~= nil then
                if TERM_PROGRAM:find("vscode", 1, true) then
                    term = "vscode"
                end
            end
        end

        -- get term from system
        if term == nil then
            local subhost = xmake._SUBHOST
            if subhost == "windows" then
                if os.getenv("XMAKE_IN_VSTUDIO") then
                    term = "vstudio"
                elseif os.getenv("WT_SESSION") then
                    term = "windows-terminal"
                elseif os.getenv("PROMPT") then -- $PROMPT == "$P$G"
                    term = "cmd"
                else
                    -- TODO maybe powershell if no $PROMPT, we need improve it
                    term = "powershell"
                end
            elseif subhost == "msys" then
                term = "msys2"
            elseif subhost == "cygwin" then
                term = "cygwin"
            elseif subhost == "macosx" then
                term = "xterm"
            end
        end

        -- get term from $TERM
        if term == nil then
            local TERM = os.getenv("TERM")
            if TERM ~= nil then
                if TERM:find("xterm", 1, true) then
                    term = "xterm"
                end
            end
        end
        tty._TERM = term or "unknown"
    end
    return term
end

-- has emoji?
function tty.has_emoji()
    local has_emoji = tty._HAS_EMOJI
    if has_emoji == nil then
        local term = tty.term()
        local winos = require("base/winos")

        -- before win7 on cmd? disable it
        if has_emoji == nil and term == "cmd" and winos.version():le("win7") then
            has_emoji = false
        end

        -- on msys2/cygwin? disable it
        if has_emoji == nil and (term == "msys2" or term == "cygwin") then
            has_emoji = false
        end

        -- enable it by default
        if has_emoji == nil then
            has_emoji = true
        end
        tty._HAS_EMOJI = has_emoji or false
    end
    return has_emoji
end

-- return module
return tty