package dtmsvr

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/yedf/dtm/common"
	"github.com/yedf/dtm/dtmcli"
	"github.com/yedf/dtm/dtmgrpc"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"google.golang.org/protobuf/types/known/emptypb"
	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

// TransGlobal global transaction
type TransGlobal struct {
	common.ModelBase
	Gid              string `json:"gid"`
	TransType        string `json:"trans_type"`
	Data             string `json:"data"`
	Status           string `json:"status"`
	QueryPrepared    string `json:"query_prepared"`
	Protocol         string `json:"protocol"`
	CommitTime       *time.Time
	FinishTime       *time.Time
	RollbackTime     *time.Time
	NextCronInterval int64
	NextCronTime     *time.Time
}

// TableName TableName
func (*TransGlobal) TableName() string {
	return "dtm.trans_global"
}

type transProcessor interface {
	GenBranches() []TransBranch
	ProcessOnce(db *common.DB, branches []TransBranch)
}

func (t *TransGlobal) touch(db *common.DB, interval int64) *gorm.DB {
	writeTransLog(t.Gid, "touch trans", "", "", "")
	updates := t.setNextCron(interval)
	return db.Model(&TransGlobal{}).Where("gid=?", t.Gid).Select(updates).Updates(t)
}

func (t *TransGlobal) changeStatus(db *common.DB, status string) *gorm.DB {
	writeTransLog(t.Gid, "change status", status, "", "")
	old := t.Status
	t.Status = status
	updates := t.setNextCron(config.TransCronInterval)
	updates = append(updates, "status")
	now := time.Now()
	if status == dtmcli.StatusSucceed {
		t.FinishTime = &now
		updates = append(updates, "finish_time")
	} else if status == dtmcli.StatusFailed {
		t.RollbackTime = &now
		updates = append(updates, "rollback_time")
	}
	dbr := db.Must().Model(t).Where("status=?", old).Select(updates).Updates(t)
	checkAffected(dbr)
	return dbr
}

// TransBranch branch transaction
type TransBranch struct {
	common.ModelBase
	Gid          string
	URL          string `json:"url"`
	Data         string
	BranchID     string `json:"branch_id"`
	BranchType   string
	Status       string
	FinishTime   *time.Time
	RollbackTime *time.Time
}

// TableName TableName
func (*TransBranch) TableName() string {
	return "dtm.trans_branch"
}

func (t *TransBranch) changeStatus(db *common.DB, status string) *gorm.DB {
	writeTransLog(t.Gid, "branch change", status, t.BranchID, "")
	dbr := db.Must().Model(t).Where("status=?", t.Status).Updates(M{
		"status":      status,
		"finish_time": time.Now(),
	})
	checkAffected(dbr)
	t.Status = status
	return dbr
}

func checkAffected(db1 *gorm.DB) {
	if db1.RowsAffected == 0 {
		panic(fmt.Errorf("duplicate updating"))
	}
}

type processorCreator func(*TransGlobal) transProcessor

var processorFac = map[string]processorCreator{}

func registorProcessorCreator(transType string, creator processorCreator) {
	processorFac[transType] = creator
}

func (t *TransGlobal) getProcessor() transProcessor {
	return processorFac[t.TransType](t)
}

// Process process global transaction once
func (t *TransGlobal) Process(db *common.DB, waitResult bool) dtmcli.M {
	if !waitResult {
		go t.processInner(db)
		return dtmcli.MapSuccess
	}
	submitting := t.Status == dtmcli.StatusSubmitted
	err := t.processInner(db)
	if err != nil {
		return dtmcli.M{"dtm_result": dtmcli.ResultFailure, "message": err.Error()}
	}
	if submitting && t.Status != dtmcli.StatusSucceed {
		return dtmcli.M{"dtm_result": dtmcli.ResultFailure, "message": "trans failed by user"}
	}
	return dtmcli.MapSuccess
}

func (t *TransGlobal) processInner(db *common.DB) (rerr error) {
	defer handlePanic(&rerr)
	defer func() {
		if TransProcessedTestChan != nil {
			dtmcli.Logf("processed: %s", t.Gid)
			TransProcessedTestChan <- t.Gid
			dtmcli.Logf("notified: %s", t.Gid)
		}
	}()
	dtmcli.Logf("processing: %s status: %s", t.Gid, t.Status)
	if t.Status == dtmcli.StatusPrepared && t.TransType != "msg" {
		t.changeStatus(db, "aborting")
	}
	branches := []TransBranch{}
	db.Must().Where("gid=?", t.Gid).Order("id asc").Find(&branches)
	t.getProcessor().ProcessOnce(db, branches)
	return
}

func (t *TransGlobal) setNextCron(expireIn int64) []string {
	t.NextCronInterval = expireIn
	next := time.Now().Add(time.Duration(t.NextCronInterval) * time.Second)
	t.NextCronTime = &next
	return []string{"next_cron_interval", "next_cron_time"}
}

func (t *TransGlobal) getURLResult(url string, branchID, branchType string, branchData []byte) string {
	if t.Protocol == "grpc" {
		dtmcli.PanicIf(strings.HasPrefix(url, "http"), fmt.Errorf("bad url for grpc: %s", url))
		server, method := dtmgrpc.GetServerAndMethod(url)
		conn := dtmgrpc.MustGetGrpcConn(server)
		err := conn.Invoke(context.Background(), method, &dtmgrpc.BusiRequest{
			Info: &dtmgrpc.BranchInfo{
				Gid:        t.Gid,
				TransType:  t.TransType,
				BranchID:   branchID,
				BranchType: branchType,
			},
			BusiData: branchData,
		}, &emptypb.Empty{})
		if err == nil {
			return dtmcli.ResultSuccess
		} else if status.Code(err) == codes.Aborted {
			return dtmcli.ResultFailure
		}
		return err.Error()
	}
	dtmcli.PanicIf(!strings.HasPrefix(url, "http"), fmt.Errorf("bad url for http: %s", url))
	resp, err := dtmcli.RestyClient.R().SetBody(string(branchData)).
		SetQueryParams(dtmcli.MS{
			"gid":         t.Gid,
			"trans_type":  t.TransType,
			"branch_id":   branchID,
			"branch_type": branchType,
		}).
		SetHeader("Content-type", "application/json").
		Execute(dtmcli.If(branchData == nil, "GET", "POST").(string), url)
	e2p(err)
	return resp.String()
}

func (t *TransGlobal) getBranchResult(branch *TransBranch) string {
	return t.getURLResult(branch.URL, branch.BranchID, branch.BranchType, []byte(branch.Data))
}

func (t *TransGlobal) execBranch(db *common.DB, branch *TransBranch) {
	body := t.getBranchResult(branch)
	if strings.Contains(body, dtmcli.ResultSuccess) {
		t.touch(db, config.TransCronInterval)
		branch.changeStatus(db, dtmcli.StatusSucceed)
	} else if t.TransType == "saga" && branch.BranchType == dtmcli.BranchAction && strings.Contains(body, dtmcli.ResultFailure) {
		t.touch(db, config.TransCronInterval)
		branch.changeStatus(db, dtmcli.StatusFailed)
	} else {
		panic(fmt.Errorf("http result should contains SUCCESS|FAILURE. grpc error should return nil|Aborted. \nrefer to: https://dtm.pub/summary/arch.html#http\nunkown result will be retried: %s", body))
	}
}

func (t *TransGlobal) saveNew(db *common.DB) {
	err := db.Transaction(func(db1 *gorm.DB) error {
		db := &common.DB{DB: db1}
		updates := t.setNextCron(config.TransCronInterval)
		writeTransLog(t.Gid, "create trans", t.Status, "", t.Data)
		dbr := db.Must().Clauses(clause.OnConflict{
			DoNothing: true,
		}).Create(t)
		if dbr.RowsAffected > 0 { // 如果这个是新事务，保存所有的分支
			branches := t.getProcessor().GenBranches()
			if len(branches) > 0 {
				writeTransLog(t.Gid, "save branches", t.Status, "", dtmcli.MustMarshalString(branches))
				checkLocalhost(branches)
				db.Must().Clauses(clause.OnConflict{
					DoNothing: true,
				}).Create(&branches)
			}
		} else if dbr.RowsAffected == 0 && t.Status == dtmcli.StatusSubmitted { // 如果数据库已经存放了prepared的事务，则修改状态
			dbr = db.Must().Model(t).Where("gid=? and status=?", t.Gid, dtmcli.StatusPrepared).Select(append(updates, "status")).Updates(t)
		}
		return nil
	})
	e2p(err)
}

// TransFromContext TransFromContext
func TransFromContext(c *gin.Context) *TransGlobal {
	data := M{}
	b, err := c.GetRawData()
	e2p(err)
	dtmcli.MustUnmarshal(b, &data)
	dtmcli.Logf("creating trans in prepare")
	if data["steps"] != nil {
		data["data"] = dtmcli.MustMarshalString(data["steps"])
	}
	m := TransGlobal{}
	dtmcli.MustRemarshal(data, &m)
	m.Protocol = "http"
	return &m
}

// TransFromDtmRequest TransFromContext
func TransFromDtmRequest(c *dtmgrpc.DtmRequest) *TransGlobal {
	return &TransGlobal{
		Gid:           c.Gid,
		TransType:     c.TransType,
		QueryPrepared: c.QueryPrepared,
		Data:          c.Data,
		Protocol:      "grpc",
	}
}

// TransFromDb construct trans from db
func TransFromDb(db *common.DB, gid string) *TransGlobal {
	m := TransGlobal{}
	dbr := db.Must().Model(&m).Where("gid=?", gid).First(&m)
	if dbr.Error == gorm.ErrRecordNotFound {
		return nil
	}
	e2p(dbr.Error)
	return &m
}

func checkLocalhost(branches []TransBranch) {
	if config.DisableLocalhost == 0 {
		return
	}
	for _, branch := range branches {
		if strings.HasPrefix(branch.URL, "http://localhost") || strings.HasPrefix(branch.URL, "localhost") {
			panic(errors.New("url for localhost is disabled. check for your config"))
		}
	}
}