--[[
 Copyright (c) 2005, Niels Martin Hansen
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-- Aegisub Automation factory-brewed script
-- "Line-per-syllable effects"

-- Use karaskel.lua for skeleton code
include("karaskel-adv.lua")

-- Define the name of the script
name = "Line-per-syllable effects"
-- Define a description of the script
description = "Makes line-per-syllable effects, that is, each syllable in the script gets its own line. This allows for more advanced effects, such as syllables moving about separately, or overlapping each other."
-- Define the script variables that can be configured graphically
-- This is the primary point of the script, being able to configure it graphically
configuration  = {
	-- First a label to descript what special variables can be used
	[1] = {
		name = "label1";
		kind = "label";
		label = [[Variable-names are prefixed with $,
expressions are enclosed in % pairs.
Variables:
  $START = Start-time of syllable (ms)
  $END = End-time of syllable (ms)
  $MID = Time midways through the syllable (ms)
  $DUR = Duration of syllable (cs)
  $X = X-position of syllable (center)
  $WIDTH = width of syllable
  $HEIGHT = height of syllable
  (There is no $Y)
Calculation example:
  \t($start,%$start+10,\fscx110\fscy110)
  \move($x,40,%$x-$width+10%,40)
Remember you should always have a \pos or \move in your effect.]];
		hint = ""
		-- No "default", since a label doesn't have a value
	},
	-- Then a text field to input the string to replace \k's with
	-- Make the default a "NOP" string
	[2] = {
		name = "k_repstr";
		kind = "text";
		label = "Effect";
		hint = "The string to place at the start of every syllable line.";
		default = "{\\an5\\pos($X,40)\\t($START,$END,\\fry360)}"
	},
	-- Allow the user to specify whether to strip tags or not
	[3] = {
		name = "striptags";
		kind = "bool";
		label = "Strip all tags";
		hint = "Strip all formatting tags apart from the processed karaoke tags?";
		default = false
	},
	[4] = {
		name = "workstyle";
		kind = "style";
		label = "Line style";
		hint = "Only apply the effect to lines with this style. Empty means apply to all lines.";
		default = ""
	}
}
-- Mandatory values
version, kind= 3, 'basic_ass'

function do_syllable(meta, styles, config, line, syl)
	-- text is the replacement text for the syllable
	-- ktext is the karaoke effect string
	local text, ktext
	
	-- Prepare the stripped or unstripped main text
	if config.striptags then
		text = syl.text_stripped
	else
		text = syl.text
	end
	
	-- Don't bother with empty syllables
	if syl.text == "" or syl.n == 0 then
		return { n=0 }
	end
	
	-- Add the variable names to the syllable data
	syl["dur"] = syl.duration
	syl["start"] = syl.start_time
	syl["end"] = syl.end_time
	syl["mid"] = syl.start_time + syl.duration*5
	syl["x"] = syl.center + line.centerleft
	
	-- Prepare the karaoke effect string
	ktext = config.k_repstr
	
	-- Function for replacing the variables
	local function var_replacer(varname)
		varname = string.lower(varname)
		if syl[varname] ~= nil then
			return syl[varname]
		else
			aegisub.output_debug(string.format("Unknown variable name: %s", varname))
			return "$" .. varname
		end
	end
	-- Replace the variables in the ktext
	ktext = string.gsub(ktext, "$(%a+)", var_replacer)
	
	-- Function for evaluating expressions
	local function expression_evaluator(expression)
		chunk, err = loadstring(string.format("return (%s)", expression))
		if (err) ~= nil then
			aegisub.output_debug(string.format("Error parsing expression:\n%s", expression, err))
			return "%" .. expression .. "%"
		else
			return chunk()
		end
	end
	-- Find and evaluate expressions
	ktext = string.gsub(ktext, "%%([^%%]*)%%", expression_evaluator)
	
	local newline = copy_line(line)
	newline.text = ktext .. text
	
	return { n=1, [1]=newline }
end

function do_line(meta, styles, config, line)
	if config.workstyle == "" or config.workstyle == line.style then
		return karaskel.do_line(meta, styles, config, line)
	else
		return { n=1, [1]=line }
	end
end
