" Copyright 2011 The Go Authors. All rights reserved.
" Use of this source code is governed by a BSD-style
" license that can be found in the LICENSE file.
"
" This file provides a utility function that performs auto-completion of
" package names, for use by other commands.

let s:goos = $GOOS
let s:goarch = $GOARCH

if len(s:goos) == 0
    if exists('g:golang_goos')
        let s:goos = g:golang_goos
    elseif has('win32') || has('win64')
        let s:goos = 'windows'
    elseif has('macunix')
        let s:goos = 'darwin'
    else
        let s:goos = '*'
    endif
endif

if len(s:goarch) == 0
    if exists('g:golang_goarch')
        let s:goarch = g:golang_goarch
    else
        let s:goarch = '*'
    endif
endif

function! go#package#Paths()
    let dirs = []

    if !exists("s:goroot")
        if executable('go')
            let s:goroot = substitute(go#util#System('go env GOROOT'), '\n', '', 'g')
            if go#util#ShellError() != 0
                echomsg '''go env GOROOT'' failed'
            endif
        else
            let s:goroot = $GOROOT
        endif
    endif

    if len(s:goroot) != 0 && isdirectory(s:goroot)
        let dirs += [s:goroot]
    endif

    let workspaces = split($GOPATH, go#util#PathListSep())
    if workspaces != []
        let dirs += workspaces
    endif

    return dirs
endfunction

function! go#package#ImportPath(arg)
    let path = fnamemodify(resolve(a:arg), ':p')
    let dirs = go#package#Paths()

    for dir in dirs
        if len(dir) && match(path, dir) == 0
            let workspace = dir
        endif
    endfor

    if !exists('workspace')
        return -1
    endif

    let srcdir = substitute(workspace . '/src/', '//', '/', '')
    return substitute(path, srcdir, '', '')
endfunction

function! go#package#FromPath(arg)
    let path = fnamemodify(resolve(a:arg), ':p')
    let dirs = go#package#Paths()

    for dir in dirs
        if len(dir) && match(path, dir) == 0
            let workspace = dir
        endif
    endfor

    if !exists('workspace')
        return -1
    endif

    if isdirectory(path)
        return substitute(path, workspace . 'src/', '', '')
    else
        return substitute(substitute(path, workspace . 'src/', '', ''),
                         \ '/' . fnamemodify(path, ':t'), '', '')
    endif
endfunction

function! go#package#CompleteMembers(package, member)
    silent! let content = go#util#System('godoc ' . a:package)
    if go#util#ShellError() || !len(content)
        return []
    endif
    let lines = filter(split(content, "\n"),"v:val !~ '^\\s\\+$'")
    try
        let mx1 = '^\s\+\(\S+\)\s\+=\s\+.*'
        let mx2 = '^\%(const\|var\|type\|func\) \([A-Z][^ (]\+\).*'
        let candidates = map(filter(copy(lines), 'v:val =~ mx1'),
                            \ 'substitute(v:val, mx1, "\\1", "")')
                     \ + map(filter(copy(lines), 'v:val =~ mx2'),
                            \ 'substitute(v:val, mx2, "\\1", "")')
        return filter(candidates, '!stridx(v:val, a:member)')
    catch
        return []
    endtry
endfunction

function! go#package#Complete(ArgLead, CmdLine, CursorPos)
    let words = split(a:CmdLine, '\s\+', 1)

    " do not complete package members for these commands
    let neglect_commands = ["GoImportAs", "GoGuruScope"]

    if len(words) > 2 && index(neglect_commands, words[0]) == -1
        " Complete package members
        return go#package#CompleteMembers(words[1], words[2])
    endif

    let dirs = go#package#Paths()

    if len(dirs) == 0
        " should not happen
        return []
    endif

    let ret = {}
    for dir in dirs
        " this may expand to multiple lines
        let root = split(expand(dir . '/pkg/' . s:goos . '_' . s:goarch), "\n")
        call add(root, expand(dir . '/src'))
        for r in root
            for i in split(globpath(r, a:ArgLead.'*'), "\n")
                if isdirectory(i)
                    let i .= '/'
                elseif i !~ '\.a$'
                    continue
                endif
                let i = substitute(substitute(i[len(r)+1:], '[\\]', '/', 'g'),
                                  \ '\.a$', '', 'g')

                " without this the result can have duplicates in form of
                " 'encoding/json' and '/encoding/json/'
                let i = go#util#StripPathSep(i)

                let ret[i] = i
            endfor
        endfor
    endfor
    return sort(keys(ret))
endfunction

" vim:sw=4:et