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

# macro wrappers for various reflection functions

import Base: typesof, insert!

separate_kwargs(args...; kwargs...) = (args, kwargs.data)

"""
Transform a dot expression into one where each argument has been replaced by a
variable "xj" (with j an integer from 1 to the returned i).
The list `args` contains the original arguments that have been replaced.
"""
function recursive_dotcalls!(ex, args, i=1)
    if !(ex isa Expr) || ((ex.head !== :. || !(ex.args[2] isa Expr)) &&
                          (ex.head !== :call || string(ex.args[1])[1] != '.'))
        newarg = Symbol('x', i)
        if Meta.isexpr(ex, :...)
            push!(args, only(ex.args))
            return Expr(:..., newarg), i+1
        else
            push!(args, ex)
            return newarg, i+1
        end
    end
    (start, branches) = ex.head === :. ? (1, ex.args[2].args) : (2, ex.args)
    for j in start:length(branches)
        branch, i = recursive_dotcalls!(branches[j], args, i)
        branches[j] = branch
    end
    return ex, i
end

function gen_call_with_extracted_types(__module__, fcn, ex0, kws=Expr[])
    if isa(ex0, Expr)
        if ex0.head === :do && Meta.isexpr(get(ex0.args, 1, nothing), :call)
            if length(ex0.args) != 2
                return Expr(:call, :error, "ill-formed do call")
            end
            i = findlast(a->(Meta.isexpr(a, :kw) || Meta.isexpr(a, :parameters)), ex0.args[1].args)
            args = copy(ex0.args[1].args)
            insert!(args, (isnothing(i) ? 2 : i+1), ex0.args[2])
            ex0 = Expr(:call, args...)
        end
        if ex0.head === :. || (ex0.head === :call && ex0.args[1] !== :.. && string(ex0.args[1])[1] == '.')
            codemacro = startswith(string(fcn), "code_")
            if codemacro && ex0.args[2] isa Expr
                # Manually wrap a dot call in a function
                args = Any[]
                ex, i = recursive_dotcalls!(copy(ex0), args)
                xargs = [Symbol('x', j) for j in 1:i-1]
                dotfuncname = gensym("dotfunction")
                dotfuncdef = Expr(:local, Expr(:(=), Expr(:call, dotfuncname, xargs...), ex))
                return quote
                    $(esc(dotfuncdef))
                    local args = typesof($(map(esc, args)...))
                    $(fcn)($(esc(dotfuncname)), args; $(kws...))
                end
            elseif !codemacro
                fully_qualified_symbol = true # of the form A.B.C.D
                ex1 = ex0
                while ex1 isa Expr && ex1.head === :.
                    fully_qualified_symbol = (length(ex1.args) == 2 &&
                                              ex1.args[2] isa QuoteNode &&
                                              ex1.args[2].value isa Symbol)
                    fully_qualified_symbol || break
                    ex1 = ex1.args[1]
                end
                fully_qualified_symbol &= ex1 isa Symbol
                if fully_qualified_symbol
                    return quote
                        local arg1 = $(esc(ex0.args[1]))
                        if isa(arg1, Module)
                            $(if string(fcn) == "which"
                                  :(which(arg1, $(ex0.args[2])))
                              else
                                  :(error("expression is not a function call"))
                              end)
                        else
                            local args = typesof($(map(esc, ex0.args)...))
                            $(fcn)(Base.getproperty, args)
                        end
                    end
                else
                    return Expr(:call, :error, "dot expressions are not lowered to "
                                * "a single function call, so @$fcn cannot analyze "
                                * "them. You may want to use Meta.@lower to identify "
                                * "which function call to target.")
                end
            end
        end
        if any(a->(Meta.isexpr(a, :kw) || Meta.isexpr(a, :parameters)), ex0.args)
            return quote
                local arg1 = $(esc(ex0.args[1]))
                local args, kwargs = $separate_kwargs($(map(esc, ex0.args[2:end])...))
                $(fcn)(Core.kwfunc(arg1),
                       Tuple{typeof(kwargs), Core.Typeof(arg1), map(Core.Typeof, args)...};
                       $(kws...))
            end
        elseif ex0.head === :call
            return Expr(:call, fcn, esc(ex0.args[1]),
                        Expr(:call, typesof, map(esc, ex0.args[2:end])...),
                        kws...)
        elseif ex0.head === :(=) && length(ex0.args) == 2
            lhs, rhs = ex0.args
            if isa(lhs, Expr)
                if lhs.head === :(.)
                    return Expr(:call, fcn, Base.setproperty!,
                                Expr(:call, typesof, map(esc, lhs.args)..., esc(rhs)), kws...)
                elseif lhs.head === :ref
                    return Expr(:call, fcn, Base.setindex!,
                                Expr(:call, typesof, esc(lhs.args[1]), esc(rhs), map(esc, lhs.args[2:end])...), kws...)
                end
            end
        elseif ex0.head === :vcat || ex0.head === :typed_vcat
            if ex0.head === :vcat
                f, hf = Base.vcat, Base.hvcat
                args = ex0.args
            else
                f, hf = Base.typed_vcat, Base.typed_hvcat
                args = ex0.args[2:end]
            end
            if any(a->isa(a,Expr) && a.head === :row, args)
                rows = Any[ (isa(x,Expr) && x.head === :row ? x.args : Any[x]) for x in args ]
                lens = map(length, rows)
                return Expr(:call, fcn, hf,
                            Expr(:call, typesof,
                                 (ex0.head === :vcat ? [] : Any[esc(ex0.args[1])])...,
                                 Expr(:tuple, lens...),
                                 map(esc, vcat(rows...))...), kws...)
            else
                return Expr(:call, fcn, f,
                            Expr(:call, typesof, map(esc, ex0.args)...), kws...)
            end
        else
            for (head, f) in (:ref => Base.getindex, :hcat => Base.hcat, :(.) => Base.getproperty, :vect => Base.vect, Symbol("'") => Base.adjoint, :typed_hcat => Base.typed_hcat, :string => string)
                if ex0.head === head
                    return Expr(:call, fcn, f,
                                Expr(:call, typesof, map(esc, ex0.args)...), kws...)
                end
            end
        end
    end
    if isa(ex0, Expr) && ex0.head === :macrocall # Make @edit @time 1+2 edit the macro by using the types of the *expressions*
        return Expr(:call, fcn, esc(ex0.args[1]), Tuple{#=__source__=#LineNumberNode, #=__module__=#Module, Any[ Core.Typeof(a) for a in ex0.args[3:end] ]...}, kws...)
    end

    ex = Meta.lower(__module__, ex0)
    if !isa(ex, Expr)
        return Expr(:call, :error, "expression is not a function call or symbol")
    end

    exret = Expr(:none)
    if ex.head === :call
        if any(e->(isa(e, Expr) && e.head === :(...)), ex0.args) &&
            (ex.args[1] === GlobalRef(Core,:_apply_iterate) ||
             ex.args[1] === GlobalRef(Base,:_apply_iterate))
            # check for splatting
            exret = Expr(:call, ex.args[2], fcn,
                        Expr(:tuple, esc(ex.args[3]),
                            Expr(:call, typesof, map(esc, ex.args[4:end])...)))
        else
            exret = Expr(:call, fcn, esc(ex.args[1]),
                         Expr(:call, typesof, map(esc, ex.args[2:end])...), kws...)
        end
    end
    if ex.head === :thunk || exret.head === :none
        exret = Expr(:call, :error, "expression is not a function call, "
                                  * "or is too complex for @$fcn to analyze; "
                                  * "break it down to simpler parts if possible. "
                                  * "In some cases, you may want to use Meta.@lower.")
    end
    return exret
end

"""
Same behaviour as gen_call_with_extracted_types except that keyword arguments
of the form "foo=bar" are passed on to the called function as well.
The keyword arguments must be given before the mandatory argument.
"""
function gen_call_with_extracted_types_and_kwargs(__module__, fcn, ex0)
    kws = Expr[]
    arg = ex0[end] # Mandatory argument
    for i in 1:length(ex0)-1
        x = ex0[i]
        if x isa Expr && x.head === :(=) # Keyword given of the form "foo=bar"
            if length(x.args) != 2
                return Expr(:call, :error, "Invalid keyword argument: $x")
            end
            push!(kws, Expr(:kw, x.args[1], x.args[2]))
        else
            return Expr(:call, :error, "@$fcn expects only one non-keyword argument")
        end
    end
    return gen_call_with_extracted_types(__module__, fcn, arg, kws)
end

for fname in [:which, :less, :edit, :functionloc]
    @eval begin
        macro ($fname)(ex0)
            gen_call_with_extracted_types(__module__, $(Expr(:quote, fname)), ex0)
        end
    end
end

macro which(ex0::Symbol)
    ex0 = QuoteNode(ex0)
    return :(which($__module__, $ex0))
end

for fname in [:code_warntype, :code_llvm, :code_native]
    @eval begin
        macro ($fname)(ex0...)
            gen_call_with_extracted_types_and_kwargs(__module__, $(Expr(:quote, fname)), ex0)
        end
    end
end

macro code_typed(ex0...)
    thecall = gen_call_with_extracted_types_and_kwargs(__module__, :code_typed, ex0)
    quote
        local results = $thecall
        length(results) == 1 ? results[1] : results
    end
end

macro code_lowered(ex0...)
    thecall = gen_call_with_extracted_types_and_kwargs(__module__, :code_lowered, ex0)
    quote
        local results = $thecall
        length(results) == 1 ? results[1] : results
    end
end

"""
    @functionloc

Applied to a function or macro call, it evaluates the arguments to the specified call, and
returns a tuple `(filename,line)` giving the location for the method that would be called for those arguments.
It calls out to the `functionloc` function.
"""
:@functionloc

"""
    @which

Applied to a function or macro call, it evaluates the arguments to the specified call, and
returns the `Method` object for the method that would be called for those arguments. Applied
to a variable, it returns the module in which the variable was bound. It calls out to the
`which` function.
"""
:@which

"""
    @less

Evaluates the arguments to the function or macro call, determines their types, and calls the `less`
function on the resulting expression.
"""
:@less

"""
    @edit

Evaluates the arguments to the function or macro call, determines their types, and calls the `edit`
function on the resulting expression.
"""
:@edit

"""
    @code_typed

Evaluates the arguments to the function or macro call, determines their types, and calls
[`code_typed`](@ref) on the resulting expression. Use the optional argument `optimize` with

    @code_typed optimize=true foo(x)

to control whether additional optimizations, such as inlining, are also applied.
"""
:@code_typed

"""
    @code_lowered

Evaluates the arguments to the function or macro call, determines their types, and calls
[`code_lowered`](@ref) on the resulting expression.
"""
:@code_lowered

"""
    @code_warntype

Evaluates the arguments to the function or macro call, determines their types, and calls
[`code_warntype`](@ref) on the resulting expression.
"""
:@code_warntype

"""
    @code_llvm

Evaluates the arguments to the function or macro call, determines their types, and calls
[`code_llvm`](@ref) on the resulting expression.
Set the optional keyword arguments `raw`, `dump_module`, `debuginfo`, `optimize`
by putting them and their value before the function call, like this:

    @code_llvm raw=true dump_module=true debuginfo=:default f(x)
    @code_llvm optimize=false f(x)

`optimize` controls whether additional optimizations, such as inlining, are also applied.
`raw` makes all metadata and dbg.* calls visible.
`debuginfo` may be one of `:source` (default) or `:none`,  to specify the verbosity of code comments.
`dump_module` prints the entire module that encapsulates the function.
"""
:@code_llvm

"""
    @code_native

Evaluates the arguments to the function or macro call, determines their types, and calls
[`code_native`](@ref) on the resulting expression.

Set the optional keyword argument `debuginfo` by putting it before the function call, like this:

    @code_native debuginfo=:default f(x)

`debuginfo` may be one of `:source` (default) or `:none`, to specify the verbosity of code comments.
"""
:@code_native
