package xrandr

import (
	"regexp"

	"git.milar.in/milarin/bufr"
)

var modePattern = regexp.MustCompile(`^\s*(\d+?)x(\d+?)\s+(.*?)$`)
var ratePattern = regexp.MustCompile(`(\d+\.\d+)(\*)?(\+)?\s*`)

type DisplayMode struct {
	Resolution Resolution `json:"resolution"`
	Rate       float64    `json:"rate"`
}

func parseDisplayModes(r *bufr.Reader) (active, recommended *DisplayMode, allModes []DisplayMode, err error) {
	allModes = make([]DisplayMode, 0)

	var line string

	for line, err = r.StringUntil(isNewLine); err == nil; line, err = r.StringUntil(isNewLine) {
		matches := modePattern.FindStringSubmatch(line)

		// line is not a DisplayMode
		if matches == nil {
			err = nil
			break
		}

		res := NewResolutionFromString(matches[1], matches[2])

		rates := ratePattern.FindAllStringSubmatch(matches[3], -1)
		for _, rate := range rates {
			mode := DisplayMode{
				Resolution: *res,
				Rate:       atof(rate[1]),
			}
			if rate[2] == "*" {
				active = &mode
			}
			if rate[3] == "+" {
				recommended = &mode
			}
			allModes = append(allModes, mode)
		}
	}

	// last read line was not a DisplayMode. Unread line
	if err == nil {
		r.UnreadString(line)
	}

	return active, recommended, allModes, err
}