package rpcore

import (
	"context"
	"fmt"
	"github.com/GUAIK-ORG/go-snowflake/snowflake"
	"github.com/oklog/run"
	"sync"
	"time"
)

type ChildProcManager struct {
	cpt            *ChildProcTable
	snowflaker     *snowflake.Snowflake
	mainCtx        context.Context
	mainCancelFunc context.CancelFunc
	isMgrRunning   bool
	mainRunGroup   *run.Group
	msgHdl         ChildProcManagerMsgHandler
	mainMsgLoop    *MainMsgLoop
	freezed        bool
}

func NewChildProcManager(msgHandler ChildProcManagerMsgHandler) *ChildProcManager {
	flake, err := snowflake.NewSnowflake(int64(0), int64(0))
	if err != nil {
		panic(fmt.Errorf("failed init ran-proc ChildProcManager: snowflake error: %v", err))
	}
	cpm := &ChildProcManager{
		cpt:            NewChildProcTable(),
		snowflaker:     flake,
		mainCtx:        nil,
		mainCancelFunc: nil,
		isMgrRunning:   false,
		msgHdl:         msgHandler,
		mainMsgLoop:    nil,
		freezed:        true,
	}
	if cpm.msgHdl == nil {
		cpm.msgHdl = &DefaultChildProcManagerMsgHandler{}
	}
	return cpm
}

func (m *ChildProcManager) CreateTask(cfg *NewTaskConfig) (cpid int64, rerr error) {
	cpid = m.snowflaker.NextVal()
	cpti := &ChildProcTableItem{
		ID:               cpid,
		Name:             cfg.Name,
		ProcessID:        0,
		IsDaemon:         false,
		Status:           PROCSTAT_PendingToRun,
		CmdInfo:          cfg.CmdInfo,
		Cmd:              nil,
		LastStartTime:    time.Time{},
		Enabled:          true,
		TaskDoneCallback: cfg.DoneCallback,
		TaskExecTimeout:  cfg.ExecTimeout,
		ShutdownTimeout:  cfg.ShutdownTimeout,
		ShutdownActor:    cfg.ShutdownActor,
		Mutex:            sync.Mutex{},
	}
	err := m.createProc(cpti)
	if err != nil {
		return -1, fmt.Errorf("failed create task: %v", err)
	}
	return cpid, nil
}

func (m *ChildProcManager) CreateDaemon(cfg *NewDaemonConfig) (cpid int64, rerr error) {
	cpid = m.snowflaker.NextVal()
	cpti := &ChildProcTableItem{
		ID:               cpid,
		Name:             cfg.Name,
		ProcessID:        0,
		IsDaemon:         true,
		Status:           PROCSTAT_ManuallyStopped,
		CmdInfo:          cfg.CmdInfo,
		Cmd:              nil,
		LastStartTime:    time.Time{},
		Enabled:          cfg.EnableAfterCreate,
		TaskDoneCallback: nil,
		TaskExecTimeout:  0,
		ShutdownTimeout:  cfg.ShutdownTimeout,
		ShutdownActor:    cfg.ShutdownActor,
		Mutex:            sync.Mutex{},
	}
	err := m.createProc(cpti)
	if err != nil {
		return -1, fmt.Errorf("failed create daemon: %v", err)
	}
	return cpid, nil
}

func (m *ChildProcManager) EnableDaemonByID(CPID int64) error {
	if m.freezed {
		return fmt.Errorf("ChildProcManager is not running or freezed for stopping, can not modify any status")
	}
	inst, err := m.cpt.GetByID(CPID)
	if err != nil {
		return err
	}
	inst.Lock()
	inst.Enabled = true
	inst.Unlock()
	go func() {
		m.mainMsgLoop.AddMsg(&Msg{CPID: inst.ID})
	}()
	return nil
}

func (m *ChildProcManager) DisableDaemonByID(CPID int64) error {
	if m.freezed {
		return fmt.Errorf("ChildProcManager is not running or freezed for stopping, can not modify any status")
	}
	inst, err := m.cpt.GetByID(CPID)
	if err != nil {
		return err
	}
	inst.Lock()
	inst.Enabled = false
	inst.Unlock()
	go func() {
		m.mainMsgLoop.AddMsg(&Msg{CPID: inst.ID})
	}()
	return nil
}

func (m *ChildProcManager) ForceKill(CPID int64) error {
	inst, err := m.cpt.GetByID(CPID)
	if err != nil {
		return err
	}
	inst.Lock()
	err = inst.Cmd.Process.Kill()
	inst.Unlock()
	if err != nil {
		return err
	}
	return nil
}

func (m *ChildProcManager) GetStatusByID(CPID int64) (*DisplayStatusInfo, error) {
	inst, err := m.cpt.GetByID(CPID)
	if err != nil {
		return nil, err
	}
	return &DisplayStatusInfo{
		CPID:          inst.ID,
		Name:          inst.Name,
		Status:        inst.Status,
		StatusText:    inst.Status.ToString(),
		StatusAbbr:    inst.Status.ToStringAbbr(),
		PID:           inst.ProcessID,
		LastStartTime: inst.LastStartTime,
	}, nil
}

func (m *ChildProcManager) ListAllStatus() ([]*DisplayStatusInfo, error) {
	all, err := m.cpt.ListAll()
	if err != nil {
		return nil, err
	}
	ret := make([]*DisplayStatusInfo, len(all))
	for i, v := range all {
		ret[i] = &DisplayStatusInfo{
			CPID:          v.ID,
			Name:          v.Name,
			Status:        v.Status,
			StatusText:    v.Status.ToString(),
			StatusAbbr:    v.Status.ToStringAbbr(),
			PID:           v.ProcessID,
			LastStartTime: v.LastStartTime,
		}
	}
	return ret, nil
}

func (m *ChildProcManager) QueryStatus(index string, args ...interface{}) ([]*DisplayStatusInfo, error) {
	all, err := m.cpt.DoQuery(index, args...)
	if err != nil {
		return nil, err
	}
	ret := make([]*DisplayStatusInfo, len(all))
	for i, v := range all {
		ret[i] = &DisplayStatusInfo{
			CPID:          v.ID,
			Name:          v.Name,
			Status:        v.Status,
			StatusText:    v.Status.ToString(),
			StatusAbbr:    v.Status.ToStringAbbr(),
			PID:           v.ProcessID,
			LastStartTime: v.LastStartTime,
		}
	}
	return ret, nil
}

func (m *ChildProcManager) createProc(cpti *ChildProcTableItem) error {
	if m.freezed {
		return fmt.Errorf("ChildProcManager is not running or freezed for stopping, can not modify any status")
	}
	err := m.cpt.Add(cpti)
	if err != nil {
		return err
	}
	go func() {
		m.mainMsgLoop.AddMsg(&Msg{CPID: cpti.ID})
	}()
	return nil
}

func (m *ChildProcManager) Start() chan error {
	cherr := make(chan error, 1)
	if m.isMgrRunning {
		cherr <- fmt.Errorf("ChildProcManager is already running")
	}
	ctx, cncl := context.WithCancel(context.Background())
	m.mainCtx = ctx
	m.mainCancelFunc = cncl
	m.mainMsgLoop = NewMainMsgLoop(m, ctx)
	m.mainRunGroup = &run.Group{}
	m.mainRunGroup.Add(m.mainMsgLoop.RunMsgLoop, m.mainMsgLoop.StopMainLoop)
	m.mainRunGroup.Add(m.mainMsgLoop.RunInspectionLoop, m.mainMsgLoop.StopInspectionLoop)
	go func() {
		m.isMgrRunning = true
		m.freezed = false
		err := m.mainRunGroup.Run()
		m.mainCtx = nil
		m.mainCancelFunc = nil
		m.mainMsgLoop = nil
		m.mainRunGroup = nil
		m.isMgrRunning = false
		cherr <- err
	}()
	return cherr
}

func (m *ChildProcManager) Stop() error {
	if m.isMgrRunning {
		if m.mainCancelFunc == nil {
			return fmt.Errorf("ChildProcManager internal error: cancel func is nil")
		}
		m.freezed = true
		m.mainCancelFunc()
	} else {
		return fmt.Errorf("ChildProcManager not running")
	}
	return nil
}

func (m *ChildProcManager) IsRunning() bool {
	return m.isMgrRunning
}