" Description: Helper functions for Rust commands/mappings
" Last Modified: 2023-09-11
" For bugs, patches and license go to https://github.com/rust-lang/rust.mnv

function! rust#Load()
    " Utility call to get this script loaded, for debugging
endfunction

function! rust#GetConfigVar(name, default)
    " Local buffer variable with same name takes predeence over global
    if has_key(b:, a:name)
        return get(b:, a:name)
    endif
    if has_key(g:, a:name)
        return get(g:, a:name)
    endif
    return a:default
endfunction

" Include expression {{{1

function! rust#IncludeExpr(fname) abort
    " Remove leading 'crate::' to deal with 2018 edition style 'use'
    " statements
    let l:fname = substitute(a:fname, '^crate::', '', '')

    " Remove trailing colons arising from lines like
    "
    "     use foo::{Bar, Baz};
    let l:fname = substitute(l:fname, ':\+$', '', '')

    " Replace '::' with '/'
    let l:fname = substitute(l:fname, '::', '/', 'g')

    " When we have
    "
    "    use foo::bar::baz;
    "
    " we can't tell whether baz is a module or a function; and we can't tell
    " which modules correspond to files.
    "
    " So we work our way up, trying
    "
    "     foo/bar/baz.rs
    "     foo/bar.rs
    "     foo.rs
    while l:fname !=# '.'
        let l:path = findfile(l:fname)
        if !empty(l:path)
            return l:fname
        endif
        let l:fname = fnamemodify(l:fname, ':h')
    endwhile
    return l:fname
endfunction

" Jump {{{1

function! rust#Jump(mode, function) range
    let cnt = v:count1
    normal! m'
    if a:mode ==# 'v'
        norm! gv
    endif
    let foldenable = &foldenable
    set nofoldenable
    while cnt > 0
        execute "call <SID>Jump_" . a:function . "()"
        let cnt = cnt - 1
    endwhile
    let &foldenable = foldenable
endfunction

function! s:Jump_Back()
    call search('{', 'b')
    keepjumps normal! w99[{
endfunction

function! s:Jump_Forward()
    normal! j0
    call search('{', 'b')
    keepjumps normal! w99[{%
    call search('{')
endfunction

" Run {{{1

function! rust#Run(bang, args)
    let args = s:ShellTokenize(a:args)
    if a:bang
        let idx = index(l:args, '--')
        if idx != -1
            let rustc_args = idx == 0 ? [] : l:args[:idx-1]
            let args = l:args[idx+1:]
        else
            let rustc_args = l:args
            let args = []
        endif
    else
        let rustc_args = []
    endif

    let b:rust_last_rustc_args = l:rustc_args
    let b:rust_last_args = l:args

    call s:WithPath(function("s:Run"), rustc_args, args)
endfunction

function! s:Run(dict, rustc_args, args)
    let exepath = a:dict.tmpdir.'/'.fnamemodify(a:dict.path, ':t:r')
    if has('win32')
        let exepath .= '.exe'
    endif

    let relpath = get(a:dict, 'tmpdir_relpath', a:dict.path)
    let rustc_args = [relpath, '-o', exepath] + a:rustc_args

    let rustc = exists("g:rustc_path") ? g:rustc_path : "rustc"

    let pwd = a:dict.istemp ? a:dict.tmpdir : ''
    let output = s:system(pwd, shellescape(rustc) . " " . join(map(rustc_args, 'shellescape(v:val)')))
    if output !=# ''
        echohl WarningMsg
        echo output
        echohl None
    endif
    if !v:shell_error
        exe '!' . shellescape(exepath) . " " . join(map(a:args, 'shellescape(v:val)'))
    endif
endfunction

" Expand {{{1

function! rust#Expand(bang, args)
    let args = s:ShellTokenize(a:args)
    if a:bang && !empty(l:args)
        let pretty = remove(l:args, 0)
    else
        let pretty = "expanded"
    endif
    call s:WithPath(function("s:Expand"), pretty, args)
endfunction

function! s:Expand(dict, pretty, args)
    try
        let rustc = exists("g:rustc_path") ? g:rustc_path : "rustc"

        if a:pretty =~? '^\%(everybody_loops$\|flowgraph=\)'
            let flag = '--xpretty'
        else
            let flag = '--pretty'
        endif
        let relpath = get(a:dict, 'tmpdir_relpath', a:dict.path)
        let args = [relpath, '-Z', 'unstable-options', l:flag, a:pretty] + a:args
        let pwd = a:dict.istemp ? a:dict.tmpdir : ''
        let output = s:system(pwd, shellescape(rustc) . " " . join(map(args, 'shellescape(v:val)')))
        if v:shell_error
            echohl WarningMsg
            echo output
            echohl None
        else
            new
            silent put =output
            1
            d
            setl filetype=rust
            setl buftype=nofile
            setl bufhidden=hide
            setl noswapfile
            " give the buffer a nice name
            let suffix = 1
            let basename = fnamemodify(a:dict.path, ':t:r')
            while 1
                let bufname = basename
                if suffix > 1 | let bufname .= ' ('.suffix.')' | endif
                let bufname .= '.pretty.rs'
                if bufexists(bufname)
                    let suffix += 1
                    continue
                endif
                exe 'silent noautocmd keepalt file' fnameescape(bufname)
                break
            endwhile
        endif
    endtry
endfunction

function! rust#CompleteExpand(lead, line, pos)
    if a:line[: a:pos-1] =~# '^RustExpand!\s*\S*$'
        " first argument and it has a !
        let list = ["normal", "expanded", "typed", "expanded,identified", "flowgraph=", "everybody_loops"]
        if !empty(a:lead)
            call filter(list, "v:val[:len(a:lead)-1] == a:lead")
        endif
        return list
    endif

    return glob(escape(a:lead, "*?[") . '*', 0, 1)
endfunction

" Emit {{{1

function! rust#Emit(type, args)
    let args = s:ShellTokenize(a:args)
    call s:WithPath(function("s:Emit"), a:type, args)
endfunction

function! s:Emit(dict, type, args)
    try
        let output_path = a:dict.tmpdir.'/output'

        let rustc = exists("g:rustc_path") ? g:rustc_path : "rustc"

        let relpath = get(a:dict, 'tmpdir_relpath', a:dict.path)
        let args = [relpath, '--emit', a:type, '-o', output_path] + a:args
        let pwd = a:dict.istemp ? a:dict.tmpdir : ''
        let output = s:system(pwd, shellescape(rustc) . " " . join(map(args, 'shellescape(v:val)')))
        if output !=# ''
            echohl WarningMsg
            echo output
            echohl None
        endif
        if !v:shell_error
            new
            exe 'silent keepalt read' fnameescape(output_path)
            1
            d
            if a:type ==# "llvm-ir"
                setl filetype=llvm
                let extension = 'll'
            elseif a:type ==# "asm"
                setl filetype=asm
                let extension = 's'
            endif
            setl buftype=nofile
            setl bufhidden=hide
            setl noswapfile
            if exists('l:extension')
                " give the buffer a nice name
                let suffix = 1
                let basename = fnamemodify(a:dict.path, ':t:r')
                while 1
                    let bufname = basename
                    if suffix > 1 | let bufname .= ' ('.suffix.')' | endif
                    let bufname .= '.'.extension
                    if bufexists(bufname)
                        let suffix += 1
                        continue
                    endif
                    exe 'silent noautocmd keepalt file' fnameescape(bufname)
                    break
                endwhile
            endif
        endif
    endtry
endfunction

" Utility functions {{{1

" Invokes func(dict, ...)
" Where {dict} is a dictionary with the following keys:
"   'path' - The path to the file
"   'tmpdir' - The path to a temporary directory that will be deleted when the
"              function returns.
"   'istemp' - 1 if the path is a file inside of {dict.tmpdir} or 0 otherwise.
" If {istemp} is 1 then an additional key is provided:
"   'tmpdir_relpath' - The {path} relative to the {tmpdir}.
"
" {dict.path} may be a path to a file inside of {dict.tmpdir} or it may be the
" existing path of the current buffer. If the path is inside of {dict.tmpdir}
" then it is guaranteed to have a '.rs' extension.
function! s:WithPath(func, ...)
    let buf = bufnr('')
    let saved = {}
    let dict = {}
    try
        let saved.write = &write
        set write
        let dict.path = expand('%')
        let pathisempty = empty(dict.path)

        " Always create a tmpdir in case the wrapped command wants it
        let dict.tmpdir = tempname()
        call mkdir(dict.tmpdir)

        if pathisempty || !saved.write
            let dict.istemp = 1
            " if we're doing this because of nowrite, preserve the filename
            if !pathisempty
                let filename = expand('%:t:r').".rs"
            else
                let filename = 'unnamed.rs'
            endif
            let dict.tmpdir_relpath = filename
            let dict.path = dict.tmpdir.'/'.filename

            let saved.mod = &modified
            set nomodified

            silent exe 'keepalt write! ' . fnameescape(dict.path)
            if pathisempty
                silent keepalt 0file
            endif
        else
            let dict.istemp = 0
            update
        endif

        call call(a:func, [dict] + a:000)
    finally
        if bufexists(buf)
            for [opt, value] in items(saved)
                silent call setbufvar(buf, '&'.opt, value)
                unlet value " avoid variable type mismatches
            endfor
        endif
        if has_key(dict, 'tmpdir') | silent call s:RmDir(dict.tmpdir) | endif
    endtry
endfunction

function! rust#AppendCmdLine(text)
    call setcmdpos(getcmdpos())
    let cmd = getcmdline() . a:text
    return cmd
endfunction

" Tokenize the string according to sh parsing rules
function! s:ShellTokenize(text)
    " states:
    " 0: start of word
    " 1: unquoted
    " 2: unquoted backslash
    " 3: double-quote
    " 4: double-quoted backslash
    " 5: single-quote
    let l:state = 0
    let l:current = ''
    let l:args = []
    for c in split(a:text, '\zs')
        if l:state == 0 || l:state == 1 " unquoted
            if l:c ==# ' '
                if l:state == 0 | continue | endif
                call add(l:args, l:current)
                let l:current = ''
                let l:state = 0
            elseif l:c ==# '\'
                let l:state = 2
            elseif l:c ==# '"'
                let l:state = 3
            elseif l:c ==# "'"
                let l:state = 5
            else
                let l:current .= l:c
                let l:state = 1
            endif
        elseif l:state == 2 " unquoted backslash
            if l:c !=# "\n" " can it even be \n?
                let l:current .= l:c
            endif
            let l:state = 1
        elseif l:state == 3 " double-quote
            if l:c ==# '\'
                let l:state = 4
            elseif l:c ==# '"'
                let l:state = 1
            else
                let l:current .= l:c
            endif
        elseif l:state == 4 " double-quoted backslash
            if stridx('$`"\', l:c) >= 0
                let l:current .= l:c
            elseif l:c ==# "\n" " is this even possible?
                " skip it
            else
                let l:current .= '\'.l:c
            endif
            let l:state = 3
        elseif l:state == 5 " single-quoted
            if l:c ==# "'"
                let l:state = 1
            else
                let l:current .= l:c
            endif
        endif
    endfor
    if l:state != 0
        call add(l:args, l:current)
    endif
    return l:args
endfunction

function! s:RmDir(path)
    " sanity check; make sure it's not empty, /, or $HOME
    if empty(a:path)
        echoerr 'Attempted to delete empty path'
        return 0
    elseif a:path ==# '/' || a:path ==# $HOME
        let l:path = expand(a:path)
        if l:path ==# '/' || l:path ==# $HOME
            echoerr 'Attempted to delete protected path: ' . a:path
            return 0
        endif
    endif

    if !isdirectory(a:path)
        return 0
    endif

    " delete() returns 0 when removing file successfully
    return delete(a:path, 'rf') == 0
endfunction

" Executes {cmd} with the cwd set to {pwd}, without changing MNV's cwd.
" If {pwd} is the empty string then it doesn't change the cwd.
function! s:system(pwd, cmd)
    let cmd = a:cmd
    if !empty(a:pwd)
        let cmd = 'cd ' . shellescape(a:pwd) . ' && ' . cmd
    endif
    return system(cmd)
endfunction

" Playpen Support {{{1
" Parts of gist.mnv by Yasuhiro Matsumoto <mattn.jp@gmail.com> reused
" gist.mnv available under the BSD license, available at
" http://github.com/mattn/gist-mnv
function! s:has_webapi()
    if !exists("*webapi#http#post")
        try
            call webapi#http#post()
        catch
        endtry
    endif
    return exists("*webapi#http#post")
endfunction

function! rust#Play(count, line1, line2, ...) abort
    redraw

    let l:rust_playpen_url = get(g:, 'rust_playpen_url', 'https://play.rust-lang.org/')
    let l:rust_shortener_url = get(g:, 'rust_shortener_url', 'https://is.gd/')

    if !s:has_webapi()
        echohl ErrorMsg | echomsg ':RustPlay depends on webapi.mnv (https://github.com/mattn/webapi-mnv)' | echohl None
        return
    endif

    let bufname = bufname('%')
    if a:count < 1
        let content = join(getline(a:line1, a:line2), "\n")
    else
        let save_regcont = @"
        let save_regtype = getregtype('"')
        silent! normal! gvy
        let content = @"
        call setreg('"', save_regcont, save_regtype)
    endif

    let url = l:rust_playpen_url."?code=".webapi#http#encodeURI(content)

    if strlen(url) > 5000
        echohl ErrorMsg | echomsg 'Buffer too large, max 5000 encoded characters ('.strlen(url).')' | echohl None
        return
    endif

    let payload = "format=simple&url=".webapi#http#encodeURI(url)
    let res = webapi#http#post(l:rust_shortener_url.'create.php', payload, {})
    if res.status[0] ==# '2'
        let url = res.content
    endif

    let footer = ''
    if exists('g:rust_clip_command')
        call system(g:rust_clip_command, url)
        if !v:shell_error
            let footer = ' (copied to clipboard)'
        endif
    endif
    redraw | echomsg 'Done: '.url.footer
endfunction

" Run a test under the cursor or all tests {{{1

" Finds a test function name under the cursor. Returns empty string when a
" test function is not found.
function! s:SearchTestFunctionNameUnderCursor() abort
    let cursor_line = line('.')

    " Find #[test] attribute
    if search('\m\C#\[test\]', 'bcW') is 0
        return ''
    endif

    " Move to an opening brace of the test function
    let test_func_line = search('\m\C^\s*fn\s\+\h\w*\s*(.\+{$', 'eW')
    if test_func_line is 0
        return ''
    endif

    " Search the end of test function (closing brace) to ensure that the
    " cursor position is within function definition
    if maparg('<Plug>(MatchitNormalForward)') ==# ''
        keepjumps normal! %
    else
        " Prefer matchit.mnv official plugin to native % since the plugin
        " provides better behavior than original % (#391)
        " To load the plugin, run:
        "   :packadd matchit
        execute 'keepjumps' 'normal' "\<Plug>(MatchitNormalForward)"
    endif
    if line('.') < cursor_line
        return ''
    endif

    return matchstr(getline(test_func_line), '\m\C^\s*fn\s\+\zs\h\w*')
endfunction

function! rust#Test(mods, winsize, all, options) abort
    let manifest = findfile('Cargo.toml', expand('%:p:h') . ';')
    if manifest ==# ''
        return rust#Run(1, '--test ' . a:options)
    endif

    " <count> defaults to 0, but we prefer an empty string
    let winsize = a:winsize ? a:winsize : ''

    if has('terminal')
        if has('patch-8.0.910')
            let cmd = printf('%s noautocmd %snew | terminal ++curwin ', a:mods, winsize)
        else
            let cmd = printf('%s terminal ', a:mods)
        endif
    elseif has('nmnv')
        let cmd = printf('%s noautocmd %snew | terminal ', a:mods, winsize)
    else
        let cmd = '!'
        let manifest = shellescape(manifest)
    endif

    if a:all
        if a:options ==# ''
            execute cmd . 'cargo test --manifest-path' manifest
        else
            execute cmd . 'cargo test --manifest-path' manifest a:options
        endif
        return
    endif

    let saved = getpos('.')
    try
        let func_name = s:SearchTestFunctionNameUnderCursor()
    finally
        call setpos('.', saved)
    endtry
    if func_name ==# ''
        echohl ErrorMsg
        echomsg 'No test function was found under the cursor. Please add ! to command if you want to run all tests'
        echohl None
        return
    endif
    if a:options ==# ''
        execute cmd . 'cargo test --manifest-path' manifest func_name
    else
        execute cmd . 'cargo test --manifest-path' manifest func_name a:options
    endif
endfunction

" }}}1

" mnv: set et sw=4 sts=4 ts=8:
