---------------------------------------------------------------------------
--- Prompt module for awful
--
-- @author Julien Danjou <julien@danjou.info>
-- @copyright 2008 Julien Danjou
-- @release @AWESOME_VERSION@
-- @module awful.prompt
---------------------------------------------------------------------------

-- Grab environment we need
local assert = assert
local io = io
local table = table
local math = math
local ipairs = ipairs
local pcall = pcall
local capi =
{
    selection = selection
}
local keygrabber = require("awful.keygrabber")
local util = require("awful.util")
local beautiful = require("beautiful")

local prompt = {}

--- Private data
local data = {}
data.history = {}

local search_term = nil
local function itera (inc,a, i)
	i = i + inc
	local v = a[i]
	if v then return i,v end
end

-- Load history file in history table
-- @param id The data.history identifier which is the path to the filename
-- @param max Optional parameter, the maximum number of entries in file
local function history_check_load(id, max)
    if id and id ~= ""
        and not data.history[id] then
	data.history[id] = { max = 50, table = {} }

	if max then
            data.history[id].max = max
	end

	local f = io.open(id, "r")

	-- Read history file
	if f then
            for line in f:lines() do
                if util.table.hasitem(data.history[id].table, line) == nil then
                        table.insert(data.history[id].table, line)
                        if #data.history[id].table >= data.history[id].max then
                           break
                        end
                end
            end
            f:close()
	end
    end
end

-- Save history table in history file
-- @param id The data.history identifier
local function history_save(id)
    if data.history[id] then
        local f = io.open(id, "w")
        if not f then
            local i = 0
            for d in id:gmatch(".-/") do
                i = i + #d
            end
            util.mkdir(id:sub(1, i - 1))
            f = assert(io.open(id, "w"))
        end
	for i = 1, math.min(#data.history[id].table, data.history[id].max) do
            f:write(data.history[id].table[i] .. "\n")
        end
       f:close()
    end
end

-- Return the number of items in history table regarding the id
-- @param id The data.history identifier
-- @return the number of items in history table, -1 if history is disabled
local function history_items(id)
    if data.history[id] then
        return #data.history[id].table
    else
        return -1
    end
end

-- Add an entry to the history file
-- @param id The data.history identifier
-- @param command The command to add
local function history_add(id, command)
    if data.history[id] and command ~= "" then
        local index = util.table.hasitem(data.history[id].table, command)
        if index == nil then
            table.insert(data.history[id].table, command)

            -- Do not exceed our max_cmd
            if #data.history[id].table > data.history[id].max then
                table.remove(data.history[id].table, 1)
            end

            history_save(id)
        else
            -- Bump this command to the end of history
            table.remove(data.history[id].table, index)
            table.insert(data.history[id].table, command)
            history_save(id)
        end
    end
end


-- Draw the prompt text with a cursor.
-- @param args The table of arguments.
-- @param text The text.
-- @param font The font.
-- @param prompt The text prefix.
-- @param text_color The text color.
-- @param cursor_color The cursor color.
-- @param cursor_pos The cursor position.
-- @param cursor_ul The cursor underline style.
-- @param selectall If true cursor is rendered on the entire text.
local function prompt_text_with_cursor(args)
    local char, spacer, text_start, text_end, ret
    local text = args.text or ""
    local _prompt = args.prompt or ""
    local underline = args.cursor_ul or "none"

    if args.selectall then
        if #text == 0 then char = " " else char = util.escape(text) end
        spacer = " "
        text_start = ""
        text_end = ""
    elseif #text < args.cursor_pos then
        char = " "
        spacer = ""
        text_start = util.escape(text)
        text_end = ""
    else
        char = util.escape(text:sub(args.cursor_pos, args.cursor_pos))
        spacer = " "
        text_start = util.escape(text:sub(1, args.cursor_pos - 1))
        text_end = util.escape(text:sub(args.cursor_pos + 1))
    end

    ret = _prompt .. text_start .. "<span background=\"" .. util.color_strip_alpha(args.cursor_color) .. "\" foreground=\"" .. util.color_strip_alpha(args.text_color) .. "\" underline=\"" .. underline .. "\">" .. char .. "</span>" .. text_end .. spacer
    return ret
end

--- Run a prompt in a box.
-- <p>The following readline keyboard shortcuts are implemented as expected:</p>
-- <kbd>CTRL+A</kbd>, <kbd>CTRL+B</kbd>, <kbd>CTRL+C</kbd>, <kbd>CTRL+D</kbd>,
-- <kbd>CTRL+E</kbd>, <kbd>CTRL+J</kbd>, <kbd>CTRL+M</kbd>, <kbd>CTRL+F</kbd>,
-- <kbd>CTRL+H</kbd>, <kbd>CTRL+K</kbd>, <kbd>CTRL+U</kbd>, <kbd>CTRL+W</kbd>,
-- <kbd>CTRL+BACKSPACE</kbd>, <kbd>SHIFT+INSERT</kbd>, <kbd>HOME</kbd>,
-- <kbd>END</kbd> and arrow keys.
-- <p>The following shortcuts implement additional history manipulation commands
-- where the search term is defined as the substring of the command from first
-- character to cursor position.</p>
-- <ul>
-- <li><code>CTRL+R</code>: reverse history search, matches any history entry
-- containing search term.</li>
-- <li><code>CTRL+S</code>: forward history search, matches any history entry
-- containing search term.</li>
-- <li><code>CTRL+UP</code>: ZSH up line or search, matches any history entry
-- starting with search term.</li>
-- <li><code>CTRL+DOWN</code>: ZSH down line or search, matches any history
-- entry starting with search term.</li>
-- <li><code>CTRL+DELETE</code>: delete the currently visible history entry from
-- history file.
-- This does not delete new commands or history entries under user editing.</li>
-- </ul>
-- @param args A table with optional arguments: <code>fg_cursor</code>,
-- <code>bg_cursor</code>, <code>ul_cursor</code>, <code>prompt</code>,
-- <code>text</code>, <code>selectall</code>, <code>font</code>,
-- <code>autoexec</code>.
-- @param textbox The textbox to use for the prompt.
-- @param exe_callback The callback function to call with command as argument
-- when finished.
-- @param completion_callback The callback function to call to get completion.
-- @param history_path Optional parameter: file path where the history should be
-- saved, set nil to disable history
-- @param history_max Optional parameter: set the maximum entries in history
-- file, 50 by default
-- @param done_callback Optional parameter: the callback function to always call
-- without arguments, regardless of whether the prompt was cancelled.
-- @param changed_callback Optional parameter: the callback function to call
-- with command as argument when a command was changed.
-- @param keypressed_callback Optional parameter: the callback function to call
-- with mod table, key and command as arguments when a key was pressed.
function prompt.run(args, textbox, exe_callback, completion_callback, history_path, history_max, done_callback, changed_callback, keypressed_callback)
    local grabber
    local theme = beautiful.get()
    if not args then args = {} end
    local command = args.text or ""
    local command_before_comp
    local cur_pos_before_comp
    local prettyprompt = args.prompt or ""
    local inv_col = args.fg_cursor or theme.fg_focus or "black"
    local cur_col = args.bg_cursor or theme.bg_focus or "white"
    local cur_ul = args.ul_cursor
    local text = args.text or ""
    local font = args.font or theme.font
    local selectall = args.selectall

    search_term=nil

    history_check_load(history_path, history_max)
    local history_index = history_items(history_path) + 1
    -- The cursor position
    local cur_pos = (selectall and 1) or text:wlen() + 1
    -- The completion element to use on completion request.
    local ncomp = 1
    if not textbox or not exe_callback then
        return
    end
    textbox:set_font(font)
    textbox:set_markup(prompt_text_with_cursor{
        text = text, text_color = inv_col, cursor_color = cur_col,
        cursor_pos = cur_pos, cursor_ul = cur_ul, selectall = selectall,
        prompt = prettyprompt })

    local exec = function()
        textbox:set_markup("")
        history_add(history_path, command)
        keygrabber.stop(grabber)
        exe_callback(command)
        if done_callback then done_callback() end
    end

    -- Update textbox
    local function update()
        textbox:set_font(font)
        textbox:set_markup(prompt_text_with_cursor{
                               text = command, text_color = inv_col, cursor_color = cur_col,
                               cursor_pos = cur_pos, cursor_ul = cur_ul, selectall = selectall,
                               prompt = prettyprompt })
    end

    grabber = keygrabber.run(
    function (modifiers, key, event)
        if event ~= "press" then return end
        -- Convert index array to hash table
        local mod = {}
        for k, v in ipairs(modifiers) do mod[v] = true end

        -- Call the user specified callback. If it returns true as
        -- the first result then return from the function. Treat the
        -- second and third results as a new command and new prompt
        -- to be set (if provided)
        if keypressed_callback then
            local user_catched, new_command, new_prompt =
                keypressed_callback(mod, key, command)
            if new_command or new_prompt then
                if new_command then
                    command = new_command
                end
                if new_prompt then
                    prettyprompt = new_prompt
                end
                update()
            end
            if user_catched then
                if changed_callback then
                    changed_callback(command)
                end
                return
            end
        end

        -- Get out cases
        if (mod.Control and (key == "c" or key == "g"))
            or (not mod.Control and key == "Escape") then
            keygrabber.stop(grabber)
            textbox:set_markup("")
            history_save(history_path)
            if done_callback then done_callback() end
            return false
        elseif (mod.Control and (key == "j" or key == "m"))
            or (not mod.Control and key == "Return")
            or (not mod.Control and key == "KP_Enter") then
            exec()
            -- We already unregistered ourselves so we don't want to return
            -- true, otherwise we may unregister someone else.
            return
        end

        -- Control cases
        if mod.Control then
            selectall = nil
            if key == "a" then
                cur_pos = 1
            elseif key == "b" then
                if cur_pos > 1 then
                    cur_pos = cur_pos - 1
                end
            elseif key == "d" then
                if cur_pos <= #command then
                    command = command:sub(1, cur_pos - 1) .. command:sub(cur_pos + 1)
                end
            elseif key == "e" then
                cur_pos = #command + 1
            elseif key == "r" then
                search_term = search_term or command:sub(1, cur_pos - 1)
                for i,v in (function(a,i) return itera(-1,a,i) end), data.history[history_path].table, history_index do
                    if v:find(search_term,1,true) ~= nil then
                        command=v
                        history_index=i
                        cur_pos=#command+1
                        break
                    end
                end
            elseif key == "s" then
                search_term = search_term or command:sub(1, cur_pos - 1)
                for i,v in (function(a,i) return itera(1,a,i) end), data.history[history_path].table, history_index do
                    if v:find(search_term,1,true) ~= nil then
                        command=v
                        history_index=i
                        cur_pos=#command+1
                        break
                    end
                end
            elseif key == "f" then
                if cur_pos <= #command then
                    cur_pos = cur_pos + 1
                end
            elseif key == "h" then
                if cur_pos > 1 then
                    command = command:sub(1, cur_pos - 2) .. command:sub(cur_pos)
                    cur_pos = cur_pos - 1
                end
            elseif key == "k" then
                command = command:sub(1, cur_pos - 1)
            elseif key == "u" then
                command = command:sub(cur_pos, #command)
                cur_pos = 1
            elseif key == "Up" then
                search_term = command:sub(1, cur_pos - 1) or ""
                for i,v in (function(a,i) return itera(-1,a,i) end), data.history[history_path].table, history_index do
                    if v:find(search_term,1,true) == 1 then
                        command=v
                        history_index=i
                        break
                    end
                end
            elseif key == "Down" then
                search_term = command:sub(1, cur_pos - 1) or ""
                for i,v in (function(a,i) return itera(1,a,i) end), data.history[history_path].table, history_index do
                    if v:find(search_term,1,true) == 1 then
                        command=v
                        history_index=i
                        break
                    end
                end
            elseif key == "w" or key == "BackSpace" then
                local wstart = 1
                local wend = 1
                local cword_start = 1
                local cword_end = 1
                while wend < cur_pos do
                    wend = command:find("[{[(,.:;_-+=@/ ]", wstart)
                    if not wend then wend = #command + 1 end
                    if cur_pos >= wstart and cur_pos <= wend + 1 then
                        cword_start = wstart
                        cword_end = cur_pos - 1
                        break
                    end
                    wstart = wend + 1
                end
                command = command:sub(1, cword_start - 1) .. command:sub(cword_end + 1)
                cur_pos = cword_start
            elseif key == "Delete" then
                -- delete from history only if:
                --  we are not dealing with a new command
                --  the user has not edited an existing entry
                if command == data.history[history_path].table[history_index] then
                    table.remove(data.history[history_path].table, history_index)
                    if history_index <= history_items(history_path) then
                        command = data.history[history_path].table[history_index]
                        cur_pos = #command + 2
                    elseif history_index > 1 then
                        history_index = history_index - 1

                        command = data.history[history_path].table[history_index]
                        cur_pos = #command + 2
                    else
                        command = ""
                        cur_pos = 1
                    end
                end
            end
        else
            if completion_callback then
                if key == "Tab" or key == "ISO_Left_Tab" then
                    if key == "ISO_Left_Tab" then
                        if ncomp == 1 then return end
                        if ncomp == 2 then
                            command = command_before_comp
                            textbox:set_font(font)
                            textbox:set_markup(prompt_text_with_cursor{
                                text = command_before_comp, text_color = inv_col, cursor_color = cur_col,
                                cursor_pos = cur_pos, cursor_ul = cur_ul, selectall = selectall,
                                prompt = prettyprompt })
                            return
                        end

                        ncomp = ncomp - 2
                    elseif ncomp == 1 then
                        command_before_comp = command
                        cur_pos_before_comp = cur_pos
                    end
                    local matches
                    command, cur_pos, matches = completion_callback(command_before_comp, cur_pos_before_comp, ncomp)
                    ncomp = ncomp + 1
                    key = ""
                    -- execute if only one match found and autoexec flag set
                    if matches and #matches == 1 and args.autoexec then
                        exec()
                        return
                    end
                else
                    ncomp = 1
                end
            end

            -- Typin cases
            if mod.Shift and key == "Insert" then
                local selection = capi.selection()
                if selection then
                    -- Remove \n
                    local n = selection:find("\n")
                    if n then
                        selection = selection:sub(1, n - 1)
                    end
                    command = command:sub(1, cur_pos - 1) .. selection .. command:sub(cur_pos)
                    cur_pos = cur_pos + #selection
                end
            elseif key == "Home" then
                cur_pos = 1
            elseif key == "End" then
                cur_pos = #command + 1
            elseif key == "BackSpace" then
                if cur_pos > 1 then
                    command = command:sub(1, cur_pos - 2) .. command:sub(cur_pos)
                    cur_pos = cur_pos - 1
                end
            elseif key == "Delete" then
                command = command:sub(1, cur_pos - 1) .. command:sub(cur_pos + 1)
            elseif key == "Left" then
                cur_pos = cur_pos - 1
            elseif key == "Right" then
                cur_pos = cur_pos + 1
            elseif key == "Up" then
                if history_index > 1 then
                    history_index = history_index - 1

                    command = data.history[history_path].table[history_index]
                    cur_pos = #command + 2
                end
            elseif key == "Down" then
               if history_index < history_items(history_path) then
                    history_index = history_index + 1

                    command = data.history[history_path].table[history_index]
                    cur_pos = #command + 2
                elseif history_index == history_items(history_path) then
                    history_index = history_index + 1

                    command = ""
                    cur_pos = 1
                end
            else
                -- wlen() is UTF-8 aware but #key is not,
                -- so check that we have one UTF-8 char but advance the cursor of # position
                if key:wlen() == 1 then
                    if selectall then command = "" end
                    command = command:sub(1, cur_pos - 1) .. key .. command:sub(cur_pos)
                    cur_pos = cur_pos + #key
                end
            end
            if cur_pos < 1 then
                cur_pos = 1
            elseif cur_pos > #command + 1 then
                cur_pos = #command + 1
            end
            selectall = nil
        end

        local success = pcall(update)
        while not success do
            -- TODO UGLY HACK TODO
            -- Setting the text failed. Most likely reason is that the user
            -- entered a multibyte character and pressed backspace which only
            -- removed the last byte. Let's remove another byte.
            if cur_pos <= 1 then
                -- No text left?!
                break
            end

            command = command:sub(1, cur_pos - 2) .. command:sub(cur_pos)
            cur_pos = cur_pos - 1
            success = pcall(update)
        end

        if changed_callback then
            changed_callback(command)
        end
    end)
end

return prompt

-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80