import Base.cd

"""
    termtitle(dir)

Set the terminal title suffix to `dir`.
The home directory is replaced with "~", and trailing slash removed.
"""
function termtitle(dir)
    if ENV["TERM"] != "dumb"
        print("\e]0;Julia ● " *
            replace(replace(dir, homedir() => "~"), r"/$" => "") *
            "\a")
    end
end

function replsetup()
    atreplinit() do repl
        if !isdefined(repl, :interface)
            repl.interface = REPL.setup_interface(repl)
        end
        if Main.InteractiveUtils.editor().exec[1] == "e"
            Main.InteractiveUtils.define_editor(
                r"\be", wait=false) do cmd, path, line
                    `$cmd +$line $path`
                end
            Main.InteractiveUtils.define_editor(
                r"\be\b.*\s(-w|--wait|-t|--tty)", wait=true) do cmd, path, line
                    `$cmd +$line $path`
                end
        end
        if get(ENV, "INSIDE_EMACS", nothing) != "vterm"
            print("\e[5 q")
        end
        @static if VERSION >= v"1.9"
            # Reset title every prompt
            repl.interface.modes[1].prompt = () ->
                (termtitle(pwd()); REPL.contextual_prompt(repl, REPL.JULIA_PROMPT)())
        end
    end
    @eval function Base.cd(dir::AbstractString)
        err = ccall(:uv_chdir, Cint, (Cstring,), dir)
        err < 0 && Base.uv_error("cd($(repr(dir)))", err)
        termtitle(dir)
        return nothing
    end
end

clearterm() = print("\e[2J")

function termcode()
    REPL.Terminals.raw!(REPL.TerminalMenus.terminal, true)
    print("\eP+q544e\e\\")
    output = @task readuntil(stdin, "\e\\")
    schedule(output)
    Timer(0.05) do _
        istaskdone(output) || Base.throwto(output, InterruptException())
    end
    value = try
        fetch(output)
    catch
        ""
    end
    REPL.Terminals.raw!(REPL.TerminalMenus.terminal, false)
    String(hex2bytes(last(split(value, '='))))
end

const TERM_COLORS = Ref(Dict{Symbol, @NamedTuple{r::UInt8, g::UInt8, b::UInt8}}())

function termcolors(; refresh::Bool=false)
    !refresh && !isempty(TERM_COLORS[]) && return TERM_COLORS[]
    REPL.Terminals.raw!(REPL.TerminalMenus.terminal, true)
    output = @task _termcolors()
    schedule(output)
    Timer(0.5) do _
        istaskdone(output) || Base.throwto(output, InterruptException())
    end
    colors = try
        fetch(output)
    catch end
    REPL.Terminals.raw!(REPL.TerminalMenus.terminal, false)
    if !isnothing(colors)
        TERM_COLORS[] = colors
    end
    TERM_COLORS[]
end

function termtheme(; refresh::Bool=false)
    colors = termcolors(; refresh)
    white = get(colors, :white, (r=0x80, g=0x80, b=0x80))
    black = get(colors, :black, (r=0x80, g=0x80, b=0x80))
    fglevel, bglevel = sum(values(white)), sum(values(black))
    if fglevel > bglevel
        :dark
    elseif fglevel < bglevel
        :light
    else
        :unknown
    end
end

function _termcolors()
    RGBTuple = NamedTuple{(:r, :g, :b), NTuple{3, UInt8}}
    colors = Dict{Symbol, RGBTuple}()
    function readcolor(io::IO, n::Integer)
        if read(io, Char) == '\e'
            entry = readuntil(io, "\e\\")
            m = match(r"^]4;(\d+);rgb:([0-9a-f]+)/([0-9a-f]+)/([0-9a-f]+)$", entry)
            if !isnothing(m) && m.captures[1] == string(n)
                r = parse(UInt8, m.captures[2][1:2], base=16)
                g = parse(UInt8, m.captures[3][1:2], base=16)
                b = parse(UInt8, m.captures[4][1:2], base=16)
                RGBTuple((r, g, b))
            end
        end
    end
    colornames = [:black, :red, :green, :yellow, :blue, :magenta, :cyan, :white,
                  :light_black, :light_red, :light_green, :light_yellow,
                  :light_blue, :light_magenta, :light_cyan, :light_white]
    for (index, color) in enumerate(colornames)
        print(stdout, "\e]4;$(index-1);?\e\\")
        flush(stdout)
        rgb = readcolor(stdin, index - 1)
        if !isnothing(rgb)
            colors[color] = rgb
        end
    end
    colors
end

const TERM_IMAGE_PACKAGES = let pkg(uuid, name) = Base.PkgId(Base.UUID(uuid), name)
    kitty = (pkg("b7fa5abe-5c7d-46c6-a1ae-1026d0d509b9", "KittyTerminalImages"),
             :(KittyTerminalImages.pushKittyDisplay!()))
    # TODO: sixel
    Dict("xterm-kitty" => kitty)
end

const ATTEMPTED_TERMIMAGE_LOAD = Ref(false)

function load_termimage_pkg(autoinstall::Bool=true)
    ATTEMPTED_TERMIMAGE_LOAD[] && return
    pkg, pkgsetup = get(TERM_IMAGE_PACKAGES, Setup.TERM[], (nothing, nothing))
    if !isnothing(pkg) && !haskey(Base.loaded_modules, pkg)
        if !isnothing(Base.find_package(pkg.name))
            ATTEMPTED_TERMIMAGE_LOAD[] = true
            # Don't to this async because it may affect a `display` call
            # that's just about to occur.
            Core.eval(Main, :(import $(Symbol(pkg.name)); $pkgsetup))
        elseif autoinstall
            Pkg = lazypkg()
            currentproj = Pkg.project().path
            try
                Pkg.activate()
                Pkg.add(pkg.name)
                load_termimage_pkg(false)
            finally
                Pkg.activate(currentproj)
            end
        else
            @info "Consider installing $(pkg.name) for better in-terminal image previews"
        end
    end
end