// Copyright 2015 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.

package prog

import (
	"bytes"
	"strconv"
)

// LogEntry describes one program in execution log.
type LogEntry struct {
	P     *Prog
	Proc  int // index of parallel proc
	Start int // start offset in log
	End   int // end offset in log
}

func ParseLog(data []byte) []*LogEntry {
	var entries []*LogEntry
	ent := &LogEntry{}
	var cur []byte
	for pos := 0; pos < len(data); {
		nl := bytes.IndexByte(data[pos:], '\n')
		if nl == -1 {
			nl = len(data)
		} else {
			nl += pos
		}
		line := data[pos : nl+1]
		pos0 := pos
		pos = nl + 1
		const delim = "executing program "
		if delimPos := bytes.Index(line, []byte(delim)); delimPos != -1 {
			if ent.P != nil && len(ent.P.Calls) != 0 {
				ent.End = pos0
				entries = append(entries, ent)
			}
			procStart := delimPos + len(delim)
			procEnd := procStart
			for procEnd != len(line) && line[procEnd] >= '0' && line[procEnd] <= '9' {
				procEnd++
			}
			proc, _ := strconv.Atoi(string(line[procStart:procEnd]))
			ent = &LogEntry{
				Proc:  proc,
				Start: pos0,
			}
			cur = nil
			continue
		}
		if ent == nil {
			continue
		}
		tmp := append(cur, line...)
		p, err := Deserialize(tmp)
		if err != nil {
			continue
		}
		cur = tmp
		ent.P = p
	}
	if ent.P != nil && len(ent.P.Calls) != 0 {
		ent.End = len(data)
		entries = append(entries, ent)
	}
	return entries
}