// 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
	Fault     bool // program was executed with fault injection in FaultCall/FaultNth
	FaultCall int
	FaultNth  int
}

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

		if proc, ok := extractInt(line, "executing program "); ok {
			if ent.P != nil && len(ent.P.Calls) != 0 {
				ent.End = pos0
				entries = append(entries, ent)
			}
			ent = &LogEntry{
				Proc:  proc,
				Start: pos0,
			}
			if faultCall, ok := extractInt(line, "fault-call:"); ok {
				ent.Fault = true
				ent.FaultCall = faultCall
				ent.FaultNth, _ = extractInt(line, "fault-nth:")
			}
			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
}

func extractInt(line []byte, prefix string) (int, bool) {
	pos := bytes.Index(line, []byte(prefix))
	if pos == -1 {
		return 0, false
	}
	pos += len(prefix)
	end := pos
	for end != len(line) && line[end] >= '0' && line[end] <= '9' {
		end++
	}
	v, _ := strconv.Atoi(string(line[pos:end]))
	return v, true
}