// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package version

import (
	
	

	
)

// Version represents the version of a trace file.
type Version uint32

const (
	Go111   Version = 11 // v1
	Go119   Version = 19 // v1
	Go121   Version = 21 // v1
	Go122   Version = 22 // v2
	Go123   Version = 23 // v2
	Go125   Version = 25 // v2
	Current         = Go125
)

var versions = map[Version][]tracev2.EventSpec{
	// Go 1.11–1.21 use a different parser and are only set here for the sake of
	// Version.Valid.
	Go111: nil,
	Go119: nil,
	Go121: nil,

	Go122: tracev2.Specs()[:tracev2.EvUserLog+1],           // All events after are Go 1.23+.
	Go123: tracev2.Specs()[:tracev2.EvExperimentalBatch+1], // All events after are Go 1.25+.
	Go125: tracev2.Specs(),
}

// Specs returns the set of event.Specs for this version.
func ( Version) () []tracev2.EventSpec {
	return versions[]
}

// EventName returns a string name of a wire format event
// for a particular trace version.
func ( Version) ( tracev2.EventType) string {
	if !.Valid() {
		return "<invalid trace version>"
	}
	 := .Specs()
	if len() == 0 {
		return "<v1 trace event type>"
	}
	if int() < len() && [].Name != "" {
		return [].Name
	}
	return fmt.Sprintf("Invalid(%d)", )
}

func ( Version) () bool {
	,  := versions[]
	return 
}

// headerFmt is the format of the header of all Go execution traces.
const headerFmt = "go 1.%d trace\x00\x00\x00"

// ReadHeader reads the version of the trace out of the trace file's
// header, whose prefix must be present in v.
func ( io.Reader) (Version, error) {
	var  Version
	,  := fmt.Fscanf(, headerFmt, &)
	if  != nil {
		return , fmt.Errorf("bad file format: not a Go execution trace?")
	}
	if !.Valid() {
		return , fmt.Errorf("unknown or unsupported trace version go 1.%d", )
	}
	return , nil
}

// WriteHeader writes a header for a trace version v to w.
func ( io.Writer,  Version) (int, error) {
	return fmt.Fprintf(, headerFmt, )
}