package eows

import (
	"bufio"
	"io"
	"strings"
	"time"
)

// scanChars - gain character by character (or as soon as one or more characters are available)
func scanChars(data []byte, atEOF bool) (advance int, token []byte, err error) {
	if atEOF && len(data) == 0 {
		return 0, nil, nil
	}
	return len(data), data, nil
}

// _pumper is in charge to collect
func (e *ExecOverWS) _pumper(sc *bufio.Scanner, fctCB func(s string)) {

	// Select split function (default sc.ScanLines)
	if e.OutSplit == SplitChar || e.OutSplit == SplitLineTime || e.OutSplit == SplitTime {
		sc.Split(scanChars)
	}

	// Scan method according to split type
	if e.OutSplit == SplitLineTime || e.OutSplit == SplitTime {
		t0 := time.Now()
		buf := ""
		for sc.Scan() {
			buf += sc.Text()
			if time.Since(t0).Nanoseconds() > e.LineTimeSpan ||
				(e.OutSplit == SplitLineTime && strings.Contains(buf, "\n")) {
				fctCB(buf)
				buf = ""
				t0 = time.Now()
			}
			if e.procExited {
				break
			}
		}
		// Send remaining characters
		if len(buf) > 0 {
			fctCB(buf)
		}

	} else {

		for sc.Scan() {
			fctCB(sc.Text())
			if e.procExited {
				break
			}
		}
	}

}

// pipePumpStdout is in charge to forward stdout in websocket
func (e *ExecOverWS) pipePumpStdout(r io.Reader, done chan struct{}) {

	sc := bufio.NewScanner(r)

	e._pumper(sc, func(b string) {
		if e.OutputCB != nil {
			e.OutputCB(e, []byte(b), []byte{})
		}
	})

	e.logDebug("STDOUT pump exit")

	if sc.Err() != nil && !strings.Contains(sc.Err().Error(), "file already closed") {
		e.logError("stdout scan: %v", sc.Err())
	}

	close(done)
}

// pipePumpStderr is in charge to forward stderr in websocket
func (e *ExecOverWS) pipePumpStderr(r io.Reader) {

	sc := bufio.NewScanner(r)

	e._pumper(sc, func(b string) {
		if e.OutputCB != nil {
			e.OutputCB(e, []byte{}, []byte(b))
		}
	})

	e.logDebug("STDERR pump exit")

	if sc.Err() != nil && !strings.Contains(sc.Err().Error(), "file already closed") {
		e.logError("stderr scan: %v", sc.Err())
	}
}

// ptsPumpStdout is in charge to forward stdout in websocket
// (only used when PtyMode is set)
func (e *ExecOverWS) ptsPumpStdout(r io.Reader, done chan struct{}) {

	buffer := make([]byte, 1024)
	for {
		n, err := r.Read(buffer)
		if err != nil {
			if err != io.EOF &&
				!strings.Contains(err.Error(), "file already closed") {
				e.logError("Error stdout read: %v", err)
			}
			break
		}
		if n == 0 {
			continue
		}
		if e.OutputCB != nil {
			e.OutputCB(e, buffer[:n], []byte{})
		}
	}

	close(done)

	e.logDebug("Eows stdout pump exited")
}