package logic

import (
	"strings"

	"git.milar.in/milarin/gmath"
	"git.milar.in/milarin/slices"
)

// ParsePreferredProps parses properties and its corresponding priority.
// priorities are distributed exponentially in reverse order.
//
// That means the last entry will have priority 1, the second last 2, then 4, 8 and so on.
//
// Properties with name "_" will be ignored and function as a placeholder to increase the priority
// of the properties which comes before them.
//
// Properties separated by comma will have the same priorities.
//
// str usually is the return value of a call to strings.Split(str, "|")
//
// Examples:
// str = "a|b|c"       -> c:1 b:2 a:4
// str = "a|b|_|c"     -> c:1 b:4 a:8
// str = "a,b|c"       -> c:1 b:4 a:4
// str = "d|_|a,b|c"   -> c:1 b:4 a:4 d:16
//
// Additionally, properties can be converted to a generic type with the converter function
func ParsePreferredProps[T comparable](str []string, converter func(string) (T, error)) map[T]int {
	props := map[T]int{}

	for i, subProps := range slices.Reverse(str) {
		if subProps == "_" {
			continue
		}

		propPriority := gmath.Pow(2, i)
		for _, subProp := range strings.Split(subProps, ",") {
			subPropT, err := converter(subProp)
			if err != nil {
				continue
			}

			props[subPropT] = propPriority
		}
	}

	return props
}

func ParsePreferredStringProps(str []string) map[string]int {
	return ParsePreferredProps(str, func(s string) (string, error) { return s, nil })
}