//go:generate stringer -type=Op -trimprefix=OP_ -linecomment

package rrdformat

import (
	"fmt"
	"strings"

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

type Op uint8

const (
	// rrdtool 1.1.x 2001-03-10
	OP_NUMBER Op = iota
	OP_VARIABLE
	OP_INF
	OP_PREV
	OP_NEGINF
	OP_UNKN
	OP_NOW
	OP_TIME
	OP_ADD // +
	OP_MOD // %
	OP_SUB // -
	OP_MUL // *
	OP_DIV // /
	OP_SIN
	OP_DUP
	OP_EXC
	OP_POP
	OP_COS
	OP_LOG
	OP_EXP
	OP_LT
	OP_LE
	OP_GT
	OP_GE
	OP_EQ
	OP_IF
	OP_MIN
	OP_MAX
	OP_LIMIT
	OP_FLOOR
	OP_CEIL
	OP_UN
	OP_END
	OP_LTIME
	// rrdtool 1.1.x 2002-03-10
	OP_NE
	OP_ISINF
	// rrdtool 1.1.x 2002-07-06
	OP_PREV_OTHER
	// rrdtool 1.1.x 2003-07-14
	OP_COUNT
	// rrdtool 1.1.x 2004-05-04
	OP_ATAN
	// rrdtool 1.1.x 2004-08-24
	OP_SQRT
	OP_SORT
	OP_REV
	// rrdtool 1.1.x 2004-09-24
	OP_TREND
	// rrdtool 1.3.0 -- Problematic: Wasn't inserted at end
	OP_TRENDNAN
	// rrdtool 1.2.10 -- Problematic: Definition in [1.2.10,1.3.0) differs from current
	OP_ATAN2
	OP_RAD2DEG
	OP_DEG2RAD
	// rrdtool 1.4.0 -- Problematic: Wasn't inserted at end
	OP_PREDICT
	OP_PREDICTSIGMA
	// rrdtool 1.2.14 -- Problematic: Definition in [1.2.14,1.4.0) differs from current
	OP_AVG
	OP_ABS
	// rrdtool 1.3.0 -- Problematic: Definition in [1.3.0,1.4.0) differs from current
	OP_ADDNAN
	// rrdtool 1.5.0 -- Problematic: Wasn't inserted at end
	OP_MINNAN
	OP_MAXNAN
	// rrdtool 1.5.0 -- Problematic: Definition in [1.5.0-pre.2012.06.01,1.5.0-pre.2014.02.07) differs from current
	OP_MEDIAN
	// rrdtool 1.5.0
	OP_PREDICTPERC
	OP_DEPTH
	OP_COPY
	OP_ROLL
	OP_INDEX
	// rrdtool 1.5.4
	OP_STEPWIDTH
	OP_NEWDAY
	OP_NEWWEEK
	OP_NEWMONTH
	OP_NEWYEAR
	// rrdtool 1.6.0
	OP_SMIN
	OP_SMAX
	OP_STDEV
	OP_PERCENT
	OP_POW
)

func (rrd RRD) RPNCompactToString(rpnps []rrdbinary.RPNToken) (string, error) {
	strs := make([]string, len(rpnps))
	for _, rpnp := range rpnps {
		switch Op(rpnp.Op) {
		case OP_NUMBER:
			strs = append(strs, fmt.Sprintf("%d", rpnp.Val))
		case OP_VARIABLE:
			if rpnp.Val < 0 || int(rpnp.Val) >= len(rrd.DSDefs) {
				return "", fmt.Errorf("out-of-bounds %s %d", Op(rpnp.Op), rpnp.Val)
			}
			strs = append(strs, string(rrd.DSDefs[int(rpnp.Val)].DSName))
		case OP_PREV_OTHER:
			if rpnp.Val < 0 || int(rpnp.Val) >= len(rrd.DSDefs) {
				return "", fmt.Errorf("out-of-bounds %s %d", Op(rpnp.Op), rpnp.Val)
			}
			strs = append(strs, fmt.Sprintf("PREV(%s)", rrd.DSDefs[int(rpnp.Val)].DSName))
		case OP_END:
			break
		default:
			strs = append(strs, Op(rpnp.Op).String())
		}
	}
	return strings.Join(strs, ","), nil
}