---------------------------------------------------------------------------
-- @author Julien Danjou <julien@danjou.info>
-- @copyright 2008 Julien Danjou
-- @release @AWESOME_VERSION@
---------------------------------------------------------------------------

-- Grab environment we need
local io = io
local table = table

--- Completion module for awful
module("awful.completion")

-- mapping of command/completion function
local bashcomp_funcs = {}
local bashcomp_src = "/etc/bash_completion"

--- Enable programmable bash completion in awful.completion.bash at the price of
--  a slight overhead
--  @param src The bash completion source file, /etc/bash_completion by default.
function bashcomp_load(src)
    if src then bashcomp_src = src end
    local c = io.popen("/usr/bin/env bash -c 'source " .. bashcomp_src .. "; complete -p'")
    while true do
        local line = c:read("*line")
        if not line then break end
        -- if a bash function is used for completion, register it
        if line:match(".* -F .*") then
            bashcomp_funcs[line:gsub(".* (%S+)$","%1")] = line:gsub(".*-F +(%S+) .*$", "%1")
        end
    end
    c:close()
end

--- Use bash completion system to complete command and filename.
-- @param command The command line.
-- @param cur_pos The cursor position.
-- @param ncomp The element number to complete.
-- @return The new command and the new cursor position.
function bash(command, cur_pos, ncomp)
    local wstart = 1
    local wend = 1
    local words = {}
    local cword_index = 0
    local cword_start = 0
    local cword_end = 0
    local i = 1
    local comptype = "file"

    -- do nothing if we are on a letter, i.e. not at len + 1 or on a space
    if cur_pos ~= #command + 1 and command:sub(cur_pos, cur_pos) ~= " " then
        return command, cur_pos
    elseif #command == 0 then
        return command, cur_pos
    end

    while wend <= #command do
        wend = command:find(" ", wstart)
        if not wend then wend = #command + 1 end
        table.insert(words, command:sub(wstart, wend - 1))
        if cur_pos >= wstart and cur_pos <= wend + 1 then
            cword_start = wstart
            cword_end = wend
            cword_index = i
        end
        wstart = wend + 1
        i = i + 1
    end

    if cword_index == 1 then
        comptype = "command"
    end

    local bash_cmd
    if bashcomp_funcs[words[1]] then
        -- fairly complex command with inline bash script to get the possible completions
        bash_cmd = "/usr/bin/env bash -c 'source " .. bashcomp_src .. "; " ..
                   "__print_completions() { for ((i=0;i<${#COMPREPLY[*]};i++)); do echo ${COMPREPLY[i]}; done }; " ..
                   "COMP_WORDS=(" ..  command .."); COMP_LINE=\"" .. command .. "\"; " ..
                   "COMP_COUNT=" .. cur_pos ..  "; COMP_CWORD=" .. cword_index-1 .. "; " ..
                   bashcomp_funcs[words[1]] .. "; __print_completions | sort -u'"
    else
        bash_cmd = "/usr/bin/env bash -c 'compgen -A " .. comptype .. " " .. words[cword_index] .. "'"
    end
    local c = io.popen(bash_cmd)
    local output = {}
    i = 0
    while true do
        local line = c:read("*line")
        if not line then break end
        table.insert(output, line)
    end

    c:close()

    -- no completion, return
    if #output == 0 then
        return command, cur_pos
    end

    -- cycle
    while ncomp > #output do
        ncomp = ncomp - #output
    end

    local str = command:sub(1, cword_start - 1) .. output[ncomp] .. command:sub(cword_end)
    cur_pos = cword_end + #output[ncomp] + 1

    return str, cur_pos
end

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