package door

import (
	"bytes"
	"syscall"
)

// OS Specific Write
// This assumes that d.writerMutex is locked.

type OSWriter struct {
	Handle int
	BaseWriter
}

func (ow *OSWriter) Init(d *Door) {
	ow.Closed = false
	ow.Handle = d.Config.Comm_handle
	ow.TranslateNL = true // Yes, translate NL => CR+NL
	ow.nlBuffer = &bytes.Buffer{}
	// ow.restoreBuff = &bytes.Buffer{}
	ow.ansiCode = make([]byte, 0, 32)
}

func (ow *OSWriter) CP437toUnicode(output []byte) []byte {
	if ow.uniBuffer == nil {
		ow.uniBuffer = &bytes.Buffer{}
	}
	for _, ch := range output {
		// Perform translation here
		ow.uniBuffer.WriteByte(ch)
	}

	return ow.uniBuffer.Bytes()
}

func (ow *OSWriter) NewLines(output []byte) []byte {
	var pos, nextpos int
	ow.nlBuffer.Reset()

	for pos != -1 {
		nextpos = bytes.Index(output[pos:], []byte{'\n'})
		if nextpos != -1 {
			nextpos += pos
			// Something to do
			ow.nlBuffer.Write(output[pos:nextpos])
			nextpos++
			pos = nextpos
			ow.nlBuffer.Write([]byte("\r\n"))
		} else {
			ow.nlBuffer.Write(output[pos:])
			pos = nextpos // -1
		}
	}
	// log.Printf(">> %q\n", ow.nlBuffer.Bytes())
	return ow.nlBuffer.Bytes()
}

/*
// Read byte slice, add color restore (after restorepos).
func (ow *OSWriter) HandleRestoreColor(output []byte) []byte {
	// Parse out ANSI codes:
	// Look for m (color), s (savepos), u (restorepos)
	// Possibly H (goto)
	ow.restoreBuff.Reset()
	var changed bool
	var pos, nextpos int
	var outputLen int = len(output)

	// Handle the case where the CSI code continues...
	if ow.ansiCSI {
		// Continue processing CSI code
		var c byte
		for pos != outputLen {
			c = output[pos]
			pos++
			ow.ansiCode = append(ow.ansiCode, c)
			if (c >= 0x40) && (c <= 0x7f) {
				// Found it
				ow.ansiCSI = false
				break
			}
		}
		ow.restoreBuff.Write(output[0:pos])
		pos++
		if !ow.ansiCSI {
			log.Printf("CSI: %c [%q]\n", c, ow.ansiCode)
			// Process this code (if of interest)
			// Reset the buffer
			ow.ansiCode = ow.ansiCode[0:0]
		}
	}

	// To verify that we're keeping the buffer in the proper state
	changed = true

	log.Printf("raw: [%q]\n", output)

	for pos != -1 {
		nextpos = bytes.Index(output[pos:], []byte{'\x1b'})
		if nextpos != -1 {
			nextpos += pos
			// Output everything up to the \x1b
			ow.restoreBuff.Write(output[pos:nextpos])

			// Found ESC
			if output[nextpos+1] == '[' {
				// Found CSI start
				// https://en.wikipedia.org/wiki/ANSI_escape_code#CSI_(Control_Sequence_Introducer)_sequences
				ow.ansiCSI = true
				// While not the end, and not end of CSI, append to ansiCode
				var csiPos int = nextpos + 2
				var c byte
				for csiPos != outputLen {
					c = output[csiPos]
					csiPos++
					ow.ansiCode = append(ow.ansiCode, c)
					if (c >= 0x40) && (c <= 0x7f) {
						// FOUND IT!
						ow.ansiCSI = false
						break
					}
				}

				// Write out the CSI code (or what we have of it)
				ow.restoreBuff.Write(output[nextpos:csiPos])
				nextpos = csiPos

				if !ow.ansiCSI {
					log.Printf("CSI: %c [%q]\n", c, ow.ansiCode)
					// Process this code (if of interest)
					// Reset the buffer
					ow.ansiCode = ow.ansiCode[0:0]
				}
			} else {
				ow.restoreBuff.WriteByte('\x1b')
				nextpos++
			}

			pos = nextpos
		} else {
			ow.restoreBuff.Write(output[pos:])
			pos = nextpos // -1 (end)
		}
	}

	// log.Printf("<< [%q]\n>> [%q]\n", output, ow.restoreBuff.Bytes())

	if changed {
		return ow.restoreBuff.Bytes()
	} else {
		return output
	}
}
*/

// The low-lever writer function
func (ow *OSWriter) OSWrite(buffer []byte) (int, error) {
	var buff []byte = buffer

	// Filters (!)

	if ow.TranslateNL {
		buff = ow.NewLines(buff)
	}

	n, err := syscall.Write(ow.Handle, buff)
	if (err != nil) || (n != len(buff)) {
		if !ow.Closed {
			ow.Closed = true
			// Don't need to close reader, it will close itself.
			// It knows when the caller is gone before the writer ever will!
		}
	}
	return n, err
}

func (ow *OSWriter) Write(buffer []byte) (int, error) {
	if ow.Closed {
		return 0, ErrDisconnected
	}

	return ow.OSWrite(buffer)
}

func (ow *OSWriter) Stop() {
	ow.Closed = true
}

// Safe way to check if OSWriter is closed
func (ow *OSWriter) IsClosed() bool {
	return ow.Closed
}

// deprecated
/*
func (d *Door) OSWrite(buffer []byte) {
	if d.WriterClosed {
		return
	}

	if DEBUG_DOOR {
		if d.writerMutex.TryLock() {
			log.Panicln("OSWrite: writerMutex was NOT locked.")
		}
	}


	n, err := syscall.Write(d.Config.Comm_handle, buffer)
	if (err != nil) || (n != len(buffer)) {
		if !d.WriterClosed {
			d.WriterClosed = true
		}
	}
}
*/

// Deprecated
// This is the writer go routine.

/*
// The parts of interest that I'm holding off on implementing for right now.

	if strings.HasSuffix(output, RestorePos) {
		output += Color(d.LastColor)

	} else {
		d.UpdateLastColor(output, &d.LastColor)
	}

	buffer := []byte(output)

	// n, err := low_write(handle, buffer)

	n, err := syscall.Write(handle, buffer)
	if (err != nil) || (n != len(buffer)) {
		log.Println("closeChannel")
		Closed = true
		d.writerMutex.Lock()
		if !d.WriterClosed {
			d.WriterClosed = true
			// close(d.writerChannel)
		}
		d.writerMutex.Unlock()
	}
*/