package expression

import (
	"math"

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

// Operator represents an operator for mathematical expressions.
type Operator struct {
	Symbol     string
	Precedence int
	Operands   int
}

// Operators defines the operators used in the language.
// The number corresponds to the operator priority and can not be zero.
var Operators = map[string]*Operator{
	".":   {".", 13, 2},
	"λ":   {"λ", 12, 1},
	"!":   {"!", 11, 1},
	"*":   {"*", 10, 2},
	"/":   {"/", 10, 2},
	"%":   {"%", 10, 2},
	"+":   {"+", 9, 2},
	"-":   {"-", 9, 2},
	">>":  {">>", 8, 2},
	"<<":  {"<<", 8, 2},
	">":   {">", 7, 2},
	"<":   {"<", 7, 2},
	">=":  {">=", 7, 2},
	"<=":  {"<=", 7, 2},
	"==":  {"==", 6, 2},
	"!=":  {"!=", 6, 2},
	"&":   {"&", 5, 2},
	"^":   {"^", 4, 2},
	"|":   {"|", 3, 2},
	"&&":  {"&&", 2, 2},
	"||":  {"||", 1, 2},
	"=":   {"=", math.MinInt, 2},
	":=":  {":=", math.MinInt, 2},
	"+=":  {"+=", math.MinInt, 2},
	"-=":  {"-=", math.MinInt, 2},
	"*=":  {"*=", math.MinInt, 2},
	"/=":  {"/=", math.MinInt, 2},
	">>=": {">>=", math.MinInt, 2},
	"<<=": {"<<=", math.MinInt, 2},
}

func isComplete(expr *Expression) bool {
	if expr == nil {
		return false
	}

	if expr.Token.Kind == token.Identifier || expr.Token.Kind == token.Number || expr.Token.Kind == token.String {
		return true
	}

	if expr.Token.Kind == token.Operator && len(expr.Children) >= numOperands(expr.Token.Text()) {
		return true
	}

	return false
}

func numOperands(symbol string) int {
	operator, exists := Operators[symbol]

	if !exists {
		return -1
	}

	return operator.Operands
}

func precedence(symbol string) int {
	operator, exists := Operators[symbol]

	if !exists {
		return -1
	}

	return operator.Precedence
}