# This file is a part of Julia. License is MIT: https://julialang.org/license

## client.jl - frontend handling command line options, environment setup,
##             and REPL

have_color = nothing
const default_color_warn = :yellow
const default_color_error = :light_red
const default_color_info = :cyan
const default_color_debug = :blue
const default_color_input = :normal
const default_color_answer = :normal
const color_normal = text_colors[:normal]

function repl_color(key, default)
    env_str = get(ENV, key, "")
    c = tryparse(Int, env_str)
    c_conv = something(c, Symbol(env_str))
    haskey(text_colors, c_conv) ? c_conv : default
end

error_color() = repl_color("JULIA_ERROR_COLOR", default_color_error)
warn_color()  = repl_color("JULIA_WARN_COLOR" , default_color_warn)
info_color()  = repl_color("JULIA_INFO_COLOR" , default_color_info)
debug_color()  = repl_color("JULIA_DEBUG_COLOR" , default_color_debug)

input_color()  = text_colors[repl_color("JULIA_INPUT_COLOR", default_color_input)]
answer_color() = text_colors[repl_color("JULIA_ANSWER_COLOR", default_color_answer)]

stackframe_lineinfo_color() = repl_color("JULIA_STACKFRAME_LINEINFO_COLOR", :bold)
stackframe_function_color() = repl_color("JULIA_STACKFRAME_FUNCTION_COLOR", :bold)

function repl_cmd(cmd, out)
    shell = shell_split(get(ENV, "JULIA_SHELL", get(ENV, "SHELL", "/bin/sh")))
    shell_name = Base.basename(shell[1])

    # Immediately expand all arguments, so that typing e.g. ~/bin/foo works.
    cmd.exec .= expanduser.(cmd.exec)

    if isempty(cmd.exec)
        throw(ArgumentError("no cmd to execute"))
    elseif cmd.exec[1] == "cd"
        new_oldpwd = pwd()
        if length(cmd.exec) > 2
            throw(ArgumentError("cd method only takes one argument"))
        elseif length(cmd.exec) == 2
            dir = cmd.exec[2]
            if dir == "-"
                if !haskey(ENV, "OLDPWD")
                    error("cd: OLDPWD not set")
                end
                dir = ENV["OLDPWD"]
            end
            cd(dir)
        else
            cd()
        end
        ENV["OLDPWD"] = new_oldpwd
        println(out, pwd())
    else
        @static if !Sys.iswindows()
            if shell_name == "fish"
                shell_escape_cmd = "begin; $(shell_escape_posixly(cmd)); and true; end"
            else
                shell_escape_cmd = "($(shell_escape_posixly(cmd))) && true"
            end
            cmd = `$shell -c $shell_escape_cmd`
        end
        run(ignorestatus(cmd))
    end
    nothing
end

# deprecated function--preserved for DocTests.jl
function ip_matches_func(ip, func::Symbol)
    for fr in StackTraces.lookup(ip)
        if fr === StackTraces.UNKNOWN || fr.from_c
            return false
        end
        fr.func === func && return true
    end
    return false
end

function scrub_repl_backtrace(bt)
    if bt !== nothing && !(bt isa Vector{Any}) # ignore our sentinel value types
        bt = stacktrace(bt)
        # remove REPL-related frames from interactive printing
        eval_ind = findlast(frame -> !frame.from_c && frame.func === :eval, bt)
        eval_ind === nothing || deleteat!(bt, eval_ind:length(bt))
    end
    return bt
end

function display_error(io::IO, er, bt)
    printstyled(io, "ERROR: "; bold=true, color=Base.error_color())
    bt = scrub_repl_backtrace(bt)
    showerror(IOContext(io, :limit => true), er, bt, backtrace = bt!==nothing)
    println(io)
end
function display_error(io::IO, stack::Vector)
    printstyled(io, "ERROR: "; bold=true, color=Base.error_color())
    bt = Any[ (x[1], scrub_repl_backtrace(x[2])) for x in stack ]
    show_exception_stack(IOContext(io, :limit => true), bt)
    println(io)
end
display_error(stack::Vector) = display_error(stderr, stack)
display_error(er, bt=nothing) = display_error(stderr, er, bt)

function eval_user_input(errio, @nospecialize(ast), show_value::Bool)
    errcount = 0
    lasterr = nothing
    have_color = get(stdout, :color, false)::Bool
    while true
        try
            if have_color
                print(color_normal)
            end
            if lasterr !== nothing
                invokelatest(display_error, errio, lasterr)
                errcount = 0
                lasterr = nothing
            else
                ast = Meta.lower(Main, ast)
                value = Core.eval(Main, ast)
                ccall(:jl_set_global, Cvoid, (Any, Any, Any), Main, :ans, value)
                if !(value === nothing) && show_value
                    if have_color
                        print(answer_color())
                    end
                    try
                        invokelatest(display, value)
                    catch
                        @error "Evaluation succeeded, but an error occurred while displaying the value" typeof(value)
                        rethrow()
                    end
                    println()
                end
            end
            break
        catch
            if errcount > 0
                @error "SYSTEM: display_error(errio, lasterr) caused an error"
            end
            errcount += 1
            lasterr = catch_stack()
            if errcount > 2
                @error "It is likely that something important is broken, and Julia will not be able to continue normally" errcount
                break
            end
        end
    end
    isa(stdin, TTY) && println()
    nothing
end

function _parse_input_line_core(s::String, filename::String)
    ex = Meta.parseall(s, filename=filename)
    if ex isa Expr && ex.head === :toplevel
        if isempty(ex.args)
            return nothing
        end
        last = ex.args[end]
        if last isa Expr && (last.head === :error || last.head === :incomplete)
            # if a parse error happens in the middle of a multi-line input
            # return only the error, so that none of the input is evaluated.
            return last
        end
    end
    return ex
end

function parse_input_line(s::String; filename::String="none", depwarn=true)
    # For now, assume all parser warnings are depwarns
    ex = if depwarn
        _parse_input_line_core(s, filename)
    else
        with_logger(NullLogger()) do
            _parse_input_line_core(s, filename)
        end
    end
    return ex
end
parse_input_line(s::AbstractString) = parse_input_line(String(s))

# detect the reason which caused an :incomplete expression
# from the error message
# NOTE: the error messages are defined in src/julia-parser.scm
incomplete_tag(ex) = :none
function incomplete_tag(ex::Expr)
    Meta.isexpr(ex, :incomplete) || return :none
    msg = ex.args[1]
    occursin("string", msg) && return :string
    occursin("comment", msg) && return :comment
    occursin("requires end", msg) && return :block
    occursin("\"`\"", msg) && return :cmd
    occursin("character", msg) && return :char
    return :other
end

# call include() on a file, ignoring if not found
include_ifexists(mod::Module, path::AbstractString) = isfile(path) && include(mod, path)

function exec_options(opts)
    if !isempty(ARGS)
        idxs = findall(x -> x == "--", ARGS)
        length(idxs) > 0 && deleteat!(ARGS, idxs[1])
    end
    quiet                 = (opts.quiet != 0)
    startup               = (opts.startupfile != 2)
    history_file          = (opts.historyfile != 0)
    color_set             = (opts.color != 0) # --color!=auto
    global have_color     = color_set ? (opts.color == 1) : nothing # --color=on
    global is_interactive = (opts.isinteractive != 0)

    # pre-process command line argument list
    arg_is_program = !isempty(ARGS)
    repl = !arg_is_program
    cmds = unsafe_load_commands(opts.commands)
    for (cmd, arg) in cmds
        if cmd == 'e'
            arg_is_program = false
            repl = false
        elseif cmd == 'E'
            arg_is_program = false
            repl = false
        elseif cmd == 'L'
            # nothing
        elseif cmd == 'B' # --bug-report
            # If we're doing a bug report, don't load anything else. We will
            # spawn a child in which to execute these options.
            let InteractiveUtils = load_InteractiveUtils()
                InteractiveUtils.report_bug(arg)
            end
            return nothing
        else
            @warn "Unexpected command -$cmd'$arg'"
        end
    end

    # remove filename from ARGS
    global PROGRAM_FILE = arg_is_program ? popfirst!(ARGS) : ""

    # Load Distributed module only if any of the Distributed options have been specified.
    distributed_mode = (opts.worker == 1) || (opts.nprocs > 0) || (opts.machine_file != C_NULL)
    if distributed_mode
        let Distributed = require(PkgId(UUID((0x8ba89e20_285c_5b6f, 0x9357_94700520ee1b)), "Distributed"))
            Core.eval(Main, :(const Distributed = $Distributed))
            Core.eval(Main, :(using .Distributed))
        end

        invokelatest(Main.Distributed.process_opts, opts)
    end

    # load ~/.julia/config/startup.jl file
    startup && load_julia_startup()

    # process cmds list
    for (cmd, arg) in cmds
        if cmd == 'e'
            Core.eval(Main, parse_input_line(arg))
        elseif cmd == 'E'
            invokelatest(show, Core.eval(Main, parse_input_line(arg)))
            println()
        elseif cmd == 'L'
            # load file immediately on all processors
            if !distributed_mode
                include(Main, arg)
            else
                # TODO: Move this logic to Distributed and use a callback
                @sync for p in invokelatest(Main.procs)
                    @async invokelatest(Main.remotecall_wait, include, p, Main, arg)
                end
            end
        end
    end

    # load file
    if arg_is_program
        # program
        if !is_interactive::Bool
            exit_on_sigint(true)
        end
        try
            include(Main, PROGRAM_FILE)
        catch
            invokelatest(display_error, catch_stack())
            if !is_interactive::Bool
                exit(1)
            end
        end
    end
    repl |= is_interactive::Bool
    if repl
        interactiveinput = isa(stdin, TTY)
        if interactiveinput
            global is_interactive = true
            banner = (opts.banner != 0) # --banner!=no
        else
            banner = (opts.banner == 1) # --banner=yes
        end
        run_main_repl(interactiveinput, quiet, banner, history_file, color_set)
    end
    nothing
end

function load_julia_startup()
    # If the user built us with a specific Base.SYSCONFDIR, check that location first for a startup.jl file
    #   If it is not found, then continue on to the relative path based on Sys.BINDIR
    BINDIR = Sys.BINDIR::String
    SYSCONFDIR = Base.SYSCONFDIR::String
    if !isempty(SYSCONFDIR) && isfile(joinpath(BINDIR, SYSCONFDIR, "julia", "startup.jl"))
        include(Main, abspath(BINDIR, SYSCONFDIR, "julia", "startup.jl"))
    else
        include_ifexists(Main, abspath(BINDIR, "..", "etc", "julia", "startup.jl"))
    end
    !isempty(DEPOT_PATH) && include_ifexists(Main, abspath(DEPOT_PATH[1], "config", "startup.jl"))
    return nothing
end

const repl_hooks = []

"""
    atreplinit(f)

Register a one-argument function to be called before the REPL interface is initialized in
interactive sessions; this is useful to customize the interface. The argument of `f` is the
REPL object. This function should be called from within the `.julia/config/startup.jl`
initialization file.
"""
atreplinit(f::Function) = (pushfirst!(repl_hooks, f); nothing)

function __atreplinit(repl)
    for f in repl_hooks
        try
            f(repl)
        catch err
            showerror(stderr, err)
            println(stderr)
        end
    end
end
_atreplinit(repl) = invokelatest(__atreplinit, repl)

# The REPL stdlib hooks into Base using this Ref
const REPL_MODULE_REF = Ref{Module}()

function load_InteractiveUtils()
    # load interactive-only libraries
    if !isdefined(Main, :InteractiveUtils)
        try
            let InteractiveUtils = require(PkgId(UUID(0xb77e0a4c_d291_57a0_90e8_8db25a27a240), "InteractiveUtils"))
                Core.eval(Main, :(const InteractiveUtils = $InteractiveUtils))
                Core.eval(Main, :(using .InteractiveUtils))
                return InteractiveUtils
            end
        catch ex
            @warn "Failed to import InteractiveUtils into module Main" exception=(ex, catch_backtrace())
        end
        return nothing
    end
    return getfield(Main, :InteractiveUtils)
end

# run the requested sort of evaluation loop on stdio
function run_main_repl(interactive::Bool, quiet::Bool, banner::Bool, history_file::Bool, color_set::Bool)
    global active_repl

    load_InteractiveUtils()

    if interactive && isassigned(REPL_MODULE_REF)
        invokelatest(REPL_MODULE_REF[]) do REPL
            term_env = get(ENV, "TERM", @static Sys.iswindows() ? "" : "dumb")
            term = REPL.Terminals.TTYTerminal(term_env, stdin, stdout, stderr)
            banner && Base.banner(term)
            if term.term_type == "dumb"
                active_repl = REPL.BasicREPL(term)
                quiet || @warn "Terminal not fully functional"
            else
                active_repl = REPL.LineEditREPL(term, get(stdout, :color, false), true)
                active_repl.history_file = history_file
            end
            # Make sure any displays pushed in .julia/config/startup.jl ends up above the
            # REPLDisplay
            pushdisplay(REPL.REPLDisplay(active_repl))
            _atreplinit(active_repl)
            REPL.run_repl(active_repl, backend->(global active_repl_backend = backend))
        end
    else
        # otherwise provide a simple fallback
        if interactive && !quiet
            @warn "REPL provider not available: using basic fallback"
        end
        banner && Base.banner()
        let input = stdin
            if isa(input, File) || isa(input, IOStream)
                # for files, we can slurp in the whole thing at once
                ex = parse_input_line(read(input, String))
                if Meta.isexpr(ex, :toplevel)
                    # if we get back a list of statements, eval them sequentially
                    # as if we had parsed them sequentially
                    for stmt in ex.args
                        eval_user_input(stderr, stmt, true)
                    end
                    body = ex.args
                else
                    eval_user_input(stderr, ex, true)
                end
            else
                while isopen(input) || !eof(input)
                    if interactive
                        print("julia> ")
                        flush(stdout)
                    end
                    try
                        line = ""
                        ex = nothing
                        while !eof(input)
                            line *= readline(input, keep=true)
                            ex = parse_input_line(line)
                            if !(isa(ex, Expr) && ex.head === :incomplete)
                                break
                            end
                        end
                        eval_user_input(stderr, ex, true)
                    catch err
                        isa(err, InterruptException) ? print("\n\n") : rethrow()
                    end
                end
            end
        end
    end
    nothing
end

# MainInclude exists to hide Main.include and eval from `names(Main)`.
baremodule MainInclude
using ..Base
# These definitions calls Base._include rather than Base.include to get
# one-frame stacktraces for the common case of using include(fname) in Main.
include(mapexpr::Function, fname::AbstractString) = Base._include(mapexpr, Main, fname)
function include(fname::AbstractString)
    isa(fname, String) || (fname = Base.convert(String, fname)::String)
    Base._include(identity, Main, fname)
end
eval(x) = Core.eval(Main, x)
end

"""
    eval(expr)

Evaluate an expression in the global scope of the containing module.
Every `Module` (except those defined with `baremodule`) has its own 1-argument
definition of `eval`, which evaluates expressions in that module.
"""
MainInclude.eval

"""
    include([mapexpr::Function,] path::AbstractString)

Evaluate the contents of the input source file in the global scope of the containing module.
Every module (except those defined with `baremodule`) has its own
definition of `include`, which evaluates the file in that module.
Returns the result of the last evaluated expression of the input file. During including,
a task-local include path is set to the directory containing the file. Nested calls to
`include` will search relative to that path. This function is typically used to load source
interactively, or to combine files in packages that are broken into multiple source files.

The optional first argument `mapexpr` can be used to transform the included code before
it is evaluated: for each parsed expression `expr` in `path`, the `include` function
actually evaluates `mapexpr(expr)`.  If it is omitted, `mapexpr` defaults to [`identity`](@ref).

Use [`Base.include`](@ref) to evaluate a file into another module.
"""
MainInclude.include

function _start()
    empty!(ARGS)
    append!(ARGS, Core.ARGS)
    if ccall(:jl_generating_output, Cint, ()) != 0 && JLOptions().incremental == 0
        # clear old invalid pointers
        PCRE.__init__()
    end
    try
        exec_options(JLOptions())
    catch
        invokelatest(display_error, catch_stack())
        exit(1)
    end
    if is_interactive && get(stdout, :color, false)
        print(color_normal)
    end
end
