package roll

import (
	"fmt"
	"regexp"
	"strconv"
	"time"

	"git.lxtend.com/qqbot/constants"
	"git.lxtend.com/qqbot/handler"
	"git.lxtend.com/qqbot/model"
	"golang.org/x/exp/rand"
)

func init() {
	handler.RegisterHandler("roll", roll, constants.LEVEL_USER)
	handler.RegisterHelpInform("roll [次数]d[面数]", "roll", "掷骰")
}

func roll(msg model.Message) (reply *model.Reply) {
	act, err := ParseRollExpression(msg.RawMsg)
	if err != nil {
		return &model.Reply{
			ReplyMsg:       "",
			ReferOriginMsg: false,
			FromMsg:        msg,
		}
	}
	result, results := RollDice(act)
	return &model.Reply{
		ReplyMsg:       "掷骰结果: " + strconv.Itoa(result) + "点 " + fmt.Sprint(results),
		ReferOriginMsg: true,
		FromMsg:        msg,
	}
}

// RollExpression 解析结果的结构体
type RollExpression struct {
	Times int // 掷骰次数
	Sides int // 骰子面数
}

// ParseRollExpression 解析骰子表达式，例如 "3d6" 或 "1d20"
func ParseRollExpression(input string) (*RollExpression, error) {
	// 匹配类似 "3d6" 或 "1d20" 的表达式
	re := regexp.MustCompile(`(\d*)d(\d+)$`)

	matches := re.FindStringSubmatch(input)
	if len(matches) != 3 {
		return nil, fmt.Errorf("invalid roll expression: %s", input)
	}

	// 如果次数为空，默认为 1
	times := 1
	if matches[1] != "" {
		t, err := strconv.Atoi(matches[1])
		if err != nil {
			return nil, err
		}
		times = t
	}

	// 将面数转换为整数
	sides, err := strconv.Atoi(matches[2])
	if err != nil {
		return nil, err
	}

	return &RollExpression{Times: times, Sides: sides}, nil
}

func RollDice(expr *RollExpression) (int, []int) {
	rand.Seed(uint64(time.Now().UnixNano())) // 初始化随机种子

	results := make([]int, expr.Times)
	total := 0

	// 每次掷骰，并累加总和
	for i := 0; i < expr.Times; i++ {
		result := rand.Intn(expr.Sides) + 1 // 随机生成 1 到 Sides 的值
		results[i] = result
		total += result
	}

	return total, results
}