package blockchainservicelogic

import (
	"blockchain/internal/domain/usecase"
	"context"
	"fmt"
	"time"

	"blockchain/gen_result/pb/code.30cm.net/digimon/app-cloudep-blockchain"
	"blockchain/internal/svc"

	"github.com/zeromicro/go-zero/core/logx"
)

type GetHistoryKlineDataLogic struct {
	ctx    context.Context
	svcCtx *svc.ServiceContext
	logx.Logger
}

func NewGetHistoryKlineDataLogic(ctx context.Context, svcCtx *svc.ServiceContext) *GetHistoryKlineDataLogic {
	return &GetHistoryKlineDataLogic{
		ctx:    ctx,
		svcCtx: svcCtx,
		Logger: logx.WithContext(ctx),
	}
}

func (l *GetHistoryKlineDataLogic) GetHistoryKlineData(in *app_cloudep_blockchain.HistoryReq) (*app_cloudep_blockchain.OKResp, error) {
	// 1) 先驗證輸入（避免把錯誤時間丟進背景 goroutine）
	st, err := time.Parse(time.RFC3339, in.GetStartTime())
	if err != nil {
		return nil, fmt.Errorf("invalid startTime (RFC3339): %w", err)
	}
	et, err := time.Parse(time.RFC3339, in.GetEndTime())
	if err != nil {
		return nil, fmt.Errorf("invalid endTime (RFC3339): %w", err)
	}
	if !st.Before(et) {
		return nil, fmt.Errorf("startTime must be before endTime")
	}

	chunks := splitByWeeksUTC(st, et)
	if len(chunks) == 0 {
		return &app_cloudep_blockchain.OKResp{}, nil
	}

	for _, ch := range chunks {
		timeBucket := ch
		err := l.svcCtx.WorkerPools.Submit(func() {
			_ = l.svcCtx.BinanceDataSource.UpsertKline(context.Background(), usecase.QueryKline{
				Symbol:    in.GetSymbol(),
				Interval:  in.GetInterval(),
				StartTime: timeBucket.start.UnixNano(),
				EndTime:   timeBucket.end.UnixNano(),
			})
		})
		if err != nil {
			return nil, err
		}
	}

	return &app_cloudep_blockchain.OKResp{}, nil
}

// --------- 小工具：按「週一起」切段（UTC） ---------

type timeRange struct {
	start time.Time // 含
	end   time.Time // 不含
}

// 取得該時間所在「週一 00:00:00」(UTC)
func weekStartMondayUTC(t time.Time) time.Time {
	t = t.UTC()
	// Go: Sunday=0 ... Saturday=6；我們要週一=起始
	wd := int(t.Weekday())
	if wd == 0 { // Sunday
		wd = 7
	}
	// 將時間歸零到當天 00:00
	d0 := time.Date(t.Year(), t.Month(), t.Day(), 0, 0, 0, 0, time.UTC)
	// 回推到週一
	return d0.AddDate(0, 0, -(wd - 1))
}

// 將 [start,end) 切成多個「週粒度」的區間
func splitByWeeksUTC(start, end time.Time) []timeRange {
	var chunks []timeRange
	if !start.Before(end) {
		return chunks
	}
	cur := start.UTC()
	end = end.UTC()

	for cur.Before(end) {
		// 下一個週一 00:00
		nextWeekStart := weekStartMondayUTC(cur).AddDate(0, 0, 7)
		chunkEnd := end
		if nextWeekStart.Before(end) {
			chunkEnd = nextWeekStart
		}
		chunks = append(chunks, timeRange{start: cur, end: chunkEnd})
		cur = chunkEnd
	}
	return chunks
}