package expression

import (
	"git.akyoto.dev/cli/q/src/build/token"
)

// NewList generates a list of expressions from comma separated parameters.
func NewList(tokens token.List) []*Expression {
	var list []*Expression

	EachParameter(tokens, func(parameter token.List) error {
		expression := Parse(parameter)
		list = append(list, expression)
		return nil
	})

	return list
}

// EachParameter calls the callback function on each parameter in a comma separated list.
func EachParameter(tokens token.List, call func(token.List) error) error {
	start := 0
	groupLevel := 0

	for i, t := range tokens {
		switch t.Kind {
		case token.GroupStart, token.ArrayStart, token.BlockStart:
			groupLevel++

		case token.GroupEnd, token.ArrayEnd, token.BlockEnd:
			groupLevel--

		case token.Separator:
			if groupLevel > 0 {
				continue
			}

			parameter := tokens[start:i]
			err := call(parameter)

			if err != nil {
				return err
			}

			start = i + 1
		}
	}

	if start != len(tokens) {
		parameter := tokens[start:]
		return call(parameter)
	}

	return nil
}