/*
Copyright © 2022 Thomas von Dein

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 lib

import (
	"cmp"
	"regexp"
	"sort"
	"strconv"

	"github.com/araddon/dateparse"
	"codeberg.org/scip/tablizer/cfg"
)

func sortTable(conf cfg.Config, data *Tabdata) {
	if len(conf.UseSortByColumn) == 0 {
		// no sorting wanted
		return
	}

	// sanity checks
	if len(data.entries) == 0 {
		return
	}

	// actual sorting
	sort.SliceStable(data.entries, func(i, j int) bool {
		// holds the result of a sort of one column
		comparators := []int{}

		// iterate over all columns to be sorted, conf.SortMode must be identical!
		for _, column := range conf.UseSortByColumn {
			comparators = append(comparators, compare(&conf, data.entries[i][column-1], data.entries[j][column-1]))
		}

		// return the combined result
		res := cmp.Or(comparators...)

		switch res {
		case 0:
			return true
		default:
			return false
		}

	})
}

// config is not modified here, but it would be inefficient to copy it every loop
func compare(conf *cfg.Config, left string, right string) int {
	var comp bool

	switch conf.SortMode {
	case "numeric":
		left, err := strconv.Atoi(left)
		if err != nil {
			left = 0
		}

		right, err := strconv.Atoi(right)
		if err != nil {
			right = 0
		}

		comp = left < right
	case "duration":
		left := duration2int(left)
		right := duration2int(right)

		comp = left < right
	case "time":
		left, _ := dateparse.ParseAny(left)
		right, _ := dateparse.ParseAny(right)

		comp = left.Unix() < right.Unix()
	default:
		comp = left < right
	}

	if conf.SortDescending {
		comp = !comp
	}

	switch comp {
	case true:
		return 0
	default:
		return 1
	}
}

/*
We could use time.ParseDuration(), but this doesn't support days.

We  could also  use github.com/xhit/go-str2duration/v2,  which does
the job,  but it's  just another dependency,  just for  this little
gem. And  we don't need a  time.Time value. And int  is good enough
for duration comparison.

Convert a  duration into  an integer.  Valid  time units  are "s",
"m", "h" and "d".
*/
func duration2int(duration string) int {
	re := regexp.MustCompile(`(\d+)([dhms])`)
	seconds := 0

	for _, match := range re.FindAllStringSubmatch(duration, -1) {
		if len(match) == 3 {
			durationvalue, _ := strconv.Atoi(match[1])

			switch match[2][0] {
			case 'd':
				seconds += durationvalue * 86400
			case 'h':
				seconds += durationvalue * 3600
			case 'm':
				seconds += durationvalue * 60
			case 's':
				seconds += durationvalue
			}
		}
	}

	return seconds
}