// Mgmt
// Copyright (C) 2013-2021+ James Shubin and the project contributors
// Written by James Shubin <james@shubin.ca> and the project contributors
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package coredatetime

import (
	"fmt"
	"time"

	"github.com/purpleidea/mgmt/lang/funcs/simple"
	"github.com/purpleidea/mgmt/lang/types"
)

func init() {
	simple.ModuleRegister(ModuleName, "format", &types.FuncValue{
		T: types.NewType("func(a int, b str) str"),
		V: Format,
	})
}

// Format returns returns a textual representation of the input time. The format
// has to be defined like specified by the golang "time" package. The time is
// the number of seconds since the epoch, and matches what comes from our Now
// function. Golang documentation: https://golang.org/pkg/time/#Time.Format
func Format(input []types.Value) (types.Value, error) {
	epochDelta := input[0].Int()
	if epochDelta < 0 {
		return nil, fmt.Errorf("epoch delta must be positive")
	}
	format := input[1].Str()

	v := time.Unix(epochDelta, 0).Format(format)
	return &types.StrValue{
		V: v,
	}, nil
}
