// ------------------------------------------------------------------------
//   Project active2
//   Active Thing (activething.com) git.activething.com/go
//
//   File n  active.go
//   Created by DEV
//   Modified   05/04/2024
//
//   Copyright 2024 activething.com 
// ------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

package ansi

import (
	"bytes"
)


const (

	styleAttsStart Code = 1024

	bgMask  Code = 0b1111110000011111
	fgMask  Code = 0b1111111111100000
	clMask  Code = 0b0000001111111111
	txMask  Code = 0b1111110000000000
	bgShift int  = 5
	stShift     int = 10
	styleNumOps int = 3

)


var (

	g = struct {
		beginEscIni []byte
		beginEscEnd []byte
		endEsc      []byte
		charsEscs 	[]byte
		endEscStr	string

		ics 		[]struct { n []byte; f []byte; b []byte }
		itx 		[]struct { n []byte; s []byte }
	}{

		beginEscIni	: []byte("\x1b["),
		beginEscEnd	: []byte{'m'},
		endEsc		: []byte("\x1b[0m"),
		endEscStr	: "\x1b[0m",

		ics 		: []struct { n []byte; f []byte; b []byte } {
			{[]byte("none"),		[]byte{},[]byte{}},
			{[]byte("black"),	[]byte{'3','0'},[]byte{'4','0'}},
			{[]byte("red"),		[]byte{'3','1'},[]byte{'4','1'}},
			{[]byte("green"),	[]byte{'3','2'},[]byte{'4','2'}},
			{[]byte("yellow"),	[]byte{'3','3'},[]byte{'4','3'}},
			{[]byte("blue"),		[]byte{'3','4'},[]byte{'4','4'}},
			{[]byte("magenta"),	[]byte{'3','5'},[]byte{'4','5'}},
			{[]byte("cyan"),		[]byte{'3','6'},[]byte{'4','6'}},
			{[]byte("white"),	[]byte{'3','7'},[]byte{'4','7'}},
			{[]byte("hblack"),	[]byte{'9','0'},[]byte{'1','0','0'}},
			{[]byte("hred"),		[]byte{'9','1'},[]byte{'1','0','1'}},
			{[]byte("hgreen"),	[]byte{'9','2'},[]byte{'1','0','2'}},
			{[]byte("hyellow"),	[]byte{'9','3'},[]byte{'1','0','3'}},
			{[]byte("hblue"),	[]byte{'9','4'},[]byte{'1','0','4'}},
			{[]byte("hmagent"),	[]byte{'9','5'},[]byte{'1','0','5'}},
			{[]byte("hcyan"),	[]byte{'9','6'},[]byte{'1','0','6'}},
			{[]byte("hwhite"),	[]byte{'9','7'},[]byte{'1','0','7'}},
			{[]byte("default"),	[]byte{'3','7'},[]byte{'4','9'}},
		},

		itx 		: []struct { n []byte; s  []byte }{
			{[]byte("bold-on"),		[]byte{'1'}},
			{[]byte("underline-on"),	[]byte{'4'}},
			{[]byte("blink-on"),		[]byte{'5'}},
			{[]byte("bold-off"),		[]byte{'2','2'}},
			{[]byte("underline-off"),[]byte{'2','5'}},
			{[]byte("blink-off"),	[]byte{'2','7'}},
		},

		charsEscs	: genCharEscapes(),
	}

)


func genCharEscapes () []byte {
	r := make([]byte,255)
	r['@']=1
	for i:=int('A'); i<=int('Z'); i++ {
		r[i]=1
		r[i+32]=1
	}
	return r
}


func Esc (code Code) string {
	return code.Begin() }

func EscEnd () string {
	return g.endEscStr }


func FilterEscapes (data []byte) []byte {
	var buf bytes.Buffer

	for i := 0; i < len(data); {
		if data[i] != 0x1b {
			buf.WriteByte(data[i])
			i++
			continue
		}
		// Si encuentra una secuencia de escape, salta hasta encontrar un carácter alfabético.
		next := i + 1
		for next < len(data) && g.charsEscs[data[next]] == 0 {
			next++
		}
		i = next
	}

	return buf.Bytes()
}