package rrdformat

import (
	"bytes"
	"encoding"
	"encoding/binary"
	"encoding/xml"
	"math"

	"git.lukeshu.com/go/librrd/rrdformat/rrdbinary"
)

// File format versions:
//
// For the most part, the layout of the file format hasn't
// changed--the version number just indicates which enum members you
// need to support.  The only parser-breaking change is that the
// 0002->0003 transition added a few bytes to the timestamp, in order
// to go from second-precision to microsecond-precision.
//
//  - "0005" (added in rrdtool 1.5.0, 2015-04-16)
//    * added DST_DCOUNTER
//    * added DST_DDERIVE
//    * otherwise identical to "0004"
//
//  - "0004" (added in rrdtool 1.3.0, 2008-06-10)
//    * added MHWPREDICT function
//    * otherwise identical to "0003"
//
//  - "0003" (added in the unreleased rrdtool 1.1.x in 2003,
//            present in rrdtool 1.2.0, 2005-04-25)
//    * last-updated timestamp gained a `long` microsecond component
//    * otherwise identical to "0002"
//
//  - "0002" (never used by a stable release of rrdtool, but was used
//            by development versions of 1.1.x 2001-2003)
//    * added DST_CDEF
//    * added CF_HWPREDICT
//    * added CF_SEASONAL
//    * added CF_DEVPREDICT
//    * added CF_DEVSEASONAL
//    * added CF_FAILURES
//
//  - "0001" (the original in rrdtool 1.0.0, 1999-07-15)

const XMLNS = "https://oss.oetiker.ch/rrdtool/rrdtool-dump.xml"

type RRDValue = rrdbinary.Float

type Header struct {
	Cookie      rrdbinary.String     `rrdbinary:"size=3" xml:"-"`
	Version     rrdbinary.String     `rrdbinary:"size=4" xml:"version"`
	FloatCookie rrdbinary.Float      `xml:"-"`
	DSCnt       rrdbinary.Uint       `xml:"-"`
	RRACnt      rrdbinary.Uint       `xml:"-"`
	DPDStep     rrdbinary.Uint       `xml:"step"`
	Parameters  [10]rrdbinary.Unival `xml:"-"`
}

type DSDef struct {
	DSName     rrdbinary.String `rrdbinary:"size=20"`
	DSType     rrdbinary.String `rrdbinary:"size=20"`
	Parameters [10]rrdbinary.Unival
}

type RRADef struct {
	CFName rrdbinary.String `rrdbinary:"size=20"`
	RowCnt rrdbinary.Uint
	PDPCnt rrdBinary.Uint
}

type Timestamp struct {
	Sec  rrdbinary.Time
	Usec rrdbinary.Int // signed, but always >= 0
}

type PDPPrep struct {
	LastDS  rrdbinary.String `rrdbinary:"size=30"`
	Scratch [10]rrdbinary.Unival
}

type CDPPrep struct {
	Scratch [10]rrdbinary.Unival
}

type RRAPtr struct {
	CurRow rrdbinary.Uint
}

type RRDv0005 = RRDv0004
type RRDv0004 = RRDv0003

type RRDv0003 struct {
	Header      Header
	DSDefs      []DSDef
	RRADefs     []RRADef
	LastUpdated Timestamp
	PDPPrep     TODO
	CPDPrep     TODO
	RRAPtr      TODO
	Values      []RRDValue
}

type RRDv0002 = RRDv0001

type RRDv0001 struct {
	Header      Header
	DSDefs      []DSDef
	RRADefs     []RRADef
	LastUpdated rrdbinary.Timestamp
	PDPPrep     TODO
	CPDPrep     TODO
	RRAPtr      TODO
	Values      []RRDValue
}