package cmdrunner

import (
	"context"
	"fmt"
	"strconv"
	"strings"

	"github.com/google/uuid"
	"github.com/scripthaus-dev/mshell/pkg/base"
	"github.com/scripthaus-dev/mshell/pkg/packet"
	"github.com/scripthaus-dev/sh2-server/pkg/remote"
	"github.com/scripthaus-dev/sh2-server/pkg/scpacket"
	"github.com/scripthaus-dev/sh2-server/pkg/sstore"
)

const DefaultUserId = "sawka"

const (
	R_Session    = 1
	R_Screen     = 2
	R_Window     = 4
	R_Remote     = 8
	R_SessionOpt = 16
	R_ScreenOpt  = 32
	R_WindowOpt  = 64
	R_RemoteOpt  = 128
)

type resolvedIds struct {
	SessionId   string
	ScreenId    string
	WindowId    string
	RemoteId    string
	RemoteState *sstore.RemoteState
}

func SubMetaCmd(cmd string) string {
	switch cmd {
	case "s":
		return "screen"
	case "w":
		return "window"
	case "r":
		return "run"
	case "c":
		return "comment"
	case "e":
		return "eval"
	default:
		return cmd
	}
}

func firstArg(pk *scpacket.FeCommandPacketType) string {
	if len(pk.Args) == 0 {
		return ""
	}
	return pk.Args[0]
}

func resolveBool(arg string, def bool) bool {
	if arg == "" {
		return def
	}
	if arg == "0" || arg == "false" {
		return false
	}
	return true
}

func resolveSessionScreen(ctx context.Context, sessionId string, screenArg string) (string, error) {
	screens, err := sstore.GetSessionScreens(ctx, sessionId)
	if err != nil {
		return "", fmt.Errorf("could not retreive screens for session=%s", sessionId)
	}
	screenNum, err := strconv.Atoi(screenArg)
	if err == nil {
		if screenNum < 1 || screenNum > len(screens) {
			return "", fmt.Errorf("could not resolve screen #%d (out of range), valid screens 1-%d", screenNum, len(screens))
		}
		return screens[screenNum-1].ScreenId, nil
	}
	for _, screen := range screens {
		if screen.ScreenId == screenArg || screen.Name == screenArg {
			return screen.ScreenId, nil
		}
	}
	return "", fmt.Errorf("could not resolve screen '%s' (name/id not found)", screenArg)
}

func resolveSession(ctx context.Context, sessionArg string) (string, error) {
	sessions, err := sstore.GetBareSessions(ctx)
	if err != nil {
		return "", fmt.Errorf("could not retrive bare sessions")
	}
	for _, session := range sessions {
		if session.SessionId == sessionArg || session.Name == sessionArg {
			return session.SessionId, nil
		}
	}
	return "", fmt.Errorf("could not resolve sesssion '%s' (name/id not found)", sessionArg)
}

func resolveSessionId(pk *scpacket.FeCommandPacketType) (string, error) {
	sessionId := pk.Kwargs["session"]
	if sessionId == "" {
		return "", nil
	}
	if _, err := uuid.Parse(sessionId); err != nil {
		return "", fmt.Errorf("invalid sessionid '%s'", sessionId)
	}
	return sessionId, nil
}

func resolveWindowId(pk *scpacket.FeCommandPacketType, sessionId string) (string, error) {
	windowId := pk.Kwargs["window"]
	if windowId == "" {
		return "", nil
	}
	if _, err := uuid.Parse(windowId); err != nil {
		return "", fmt.Errorf("invalid windowid '%s'", windowId)
	}
	return windowId, nil
}

func resolveScreenId(ctx context.Context, pk *scpacket.FeCommandPacketType, sessionId string) (string, error) {
	screenArg := pk.Kwargs["screen"]
	if screenArg == "" {
		return "", nil
	}
	if _, err := uuid.Parse(screenArg); err == nil {
		return screenArg, nil
	}
	if sessionId == "" {
		return "", fmt.Errorf("cannot resolve screen without session")
	}
	return resolveSessionScreen(ctx, sessionId, screenArg)
}

func resolveRemote(ctx context.Context, pk *scpacket.FeCommandPacketType, sessionId string, windowId string) (string, *sstore.RemoteState, error) {
	remoteArg := pk.Kwargs["remote"]
	if remoteArg == "" {
		return "", nil, nil
	}
	remoteId, state, err := sstore.GetRemoteState(ctx, remoteArg, sessionId, windowId)
	if err != nil {
		return "", nil, fmt.Errorf("cannot resolve remote '%s': %w", remoteArg, err)
	}
	if state == nil {
		state, err = remote.GetDefaultRemoteStateById(remoteId)
		if err != nil {
			return "", nil, fmt.Errorf("cannot resolve remote '%s': %w", remoteArg, err)
		}
	}
	return remoteId, state, nil
}

func resolveIds(ctx context.Context, pk *scpacket.FeCommandPacketType, rtype int) (resolvedIds, error) {
	rtn := resolvedIds{}
	if rtype == 0 {
		return rtn, nil
	}
	var err error
	if (rtype&R_Session)+(rtype&R_SessionOpt) > 0 {
		rtn.SessionId, err = resolveSessionId(pk)
		if err != nil {
			return rtn, err
		}
		if rtn.SessionId == "" && (rtype&R_Session) > 0 {
			return rtn, fmt.Errorf("no session")
		}
	}
	if (rtype&R_Window)+(rtype&R_WindowOpt) > 0 {
		rtn.WindowId, err = resolveWindowId(pk, rtn.SessionId)
		if err != nil {
			return rtn, err
		}
		if rtn.WindowId == "" && (rtype&R_Window) > 0 {
			return rtn, fmt.Errorf("no window")
		}

	}
	if (rtype&R_Screen)+(rtype&R_ScreenOpt) > 0 {
		rtn.ScreenId, err = resolveScreenId(ctx, pk, rtn.SessionId)
		if err != nil {
			return rtn, err
		}
		if rtn.ScreenId == "" && (rtype&R_Screen) > 0 {
			return rtn, fmt.Errorf("no screen")
		}
	}
	if (rtype&R_Remote)+(rtype&R_RemoteOpt) > 0 {
		rtn.RemoteId, rtn.RemoteState, err = resolveRemote(ctx, pk, rtn.SessionId, rtn.WindowId)
		if err != nil {
			return rtn, err
		}
		if rtn.RemoteId == "" && (rtype&R_Remote) > 0 {
			return rtn, fmt.Errorf("no remote")
		}
	}
	return rtn, nil
}

func HandleCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	switch SubMetaCmd(pk.MetaCmd) {
	case "run":
		return RunCommand(ctx, pk)

	case "eval":
		return EvalCommand(ctx, pk)

	case "screen":
		return ScreenCommand(ctx, pk)

	case "session":
		return SessionCommand(ctx, pk)

	case "comment":
		return CommentCommand(ctx, pk)

	case "cd":
		return CdCommand(ctx, pk)

	default:
		return nil, fmt.Errorf("invalid command '/%s', no handler", pk.MetaCmd)
	}
}

func RunCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	ids, err := resolveIds(ctx, pk, R_Session|R_Window|R_Remote)
	if err != nil {
		return nil, fmt.Errorf("/run error: %w", err)
	}
	cmdId := uuid.New().String()
	cmdStr := firstArg(pk)
	runPacket := packet.MakeRunPacket()
	runPacket.ReqId = uuid.New().String()
	runPacket.CK = base.MakeCommandKey(ids.SessionId, cmdId)
	runPacket.Cwd = ids.RemoteState.Cwd
	runPacket.Env = nil
	runPacket.UsePty = true
	runPacket.TermOpts = &packet.TermOpts{Rows: remote.DefaultTermRows, Cols: remote.DefaultTermCols, Term: remote.DefaultTerm}
	runPacket.Command = strings.TrimSpace(cmdStr)
	cmd, err := remote.RunCommand(ctx, cmdId, ids.RemoteId, ids.RemoteState, runPacket)
	if err != nil {
		return nil, err
	}
	rtnLine, err := sstore.AddCmdLine(ctx, ids.SessionId, ids.WindowId, DefaultUserId, cmd)
	if err != nil {
		return nil, err
	}
	return sstore.LineUpdate{Line: rtnLine, Cmd: cmd}, nil
}

func EvalCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	if len(pk.Args) == 0 {
		return nil, fmt.Errorf("usage: /eval [command], no command passed to eval")
	}
	// parse metacmd
	commandStr := strings.TrimSpace(pk.Args[0])
	if commandStr == "" {
		return nil, fmt.Errorf("/eval, invalid emtpty command")
	}
	metaCmd := ""
	metaSubCmd := ""
	if commandStr == "cd" || strings.HasPrefix(commandStr, "cd ") {
		metaCmd = "cd"
		commandStr = strings.TrimSpace(commandStr[2:])
	} else if commandStr[0] == '/' {
		spaceIdx := strings.Index(commandStr, " ")
		if spaceIdx == -1 {
			metaCmd = commandStr[1:]
			commandStr = ""
		} else {
			metaCmd = commandStr[1:spaceIdx]
			commandStr = strings.TrimSpace(commandStr[spaceIdx+1:])
		}
		colonIdx := strings.Index(metaCmd, ":")
		if colonIdx != -1 {
			metaCmd, metaSubCmd = metaCmd[0:colonIdx], metaCmd[colonIdx+1:]
		}
		if metaCmd == "" {
			return nil, fmt.Errorf("invalid command, got bare '/', with no command")
		}
	}
	if metaCmd == "" {
		metaCmd = "run"
	}
	var args []string
	if metaCmd == "run" || metaCmd == "comment" {
		args = []string{commandStr}
	} else {
		args = strings.Fields(commandStr)
	}
	newPk := &scpacket.FeCommandPacketType{
		MetaCmd:    metaCmd,
		MetaSubCmd: metaSubCmd,
		Args:       args,
		Kwargs:     pk.Kwargs,
	}
	return HandleCommand(ctx, newPk)
}

func ScreenCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	if pk.MetaSubCmd == "close" {
		ids, err := resolveIds(ctx, pk, R_Session|R_Screen)
		if err != nil {
			return nil, fmt.Errorf("/screen:close cannot close screen: %w", err)
		}
		update, err := sstore.DeleteScreen(ctx, ids.SessionId, ids.ScreenId)
		if err != nil {
			return nil, err
		}
		return update, nil
	}
	if pk.MetaSubCmd == "open" || pk.MetaSubCmd == "new" {
		ids, err := resolveIds(ctx, pk, R_Session)
		if err != nil {
			return nil, fmt.Errorf("/screen:open cannot open screen: %w", err)
		}
		activate := resolveBool(pk.Kwargs["activate"], true)
		update, err := sstore.InsertScreen(ctx, ids.SessionId, pk.Kwargs["name"], activate)
		if err != nil {
			return nil, err
		}
		return update, nil
	}
	if pk.MetaSubCmd != "" {
		return nil, fmt.Errorf("invalid /screen subcommand '%s'", pk.MetaSubCmd)
	}
	ids, err := resolveIds(ctx, pk, R_Session)
	if err != nil {
		return nil, fmt.Errorf("/screen cannot switch to screen: %w", err)
	}
	firstArg := firstArg(pk)
	if firstArg == "" {
		return nil, fmt.Errorf("usage /screen [screen-name|screen-index|screen-id], no param specified")
	}
	screenIdArg, err := resolveSessionScreen(ctx, ids.SessionId, firstArg)
	if err != nil {
		return nil, err
	}
	update, err := sstore.SwitchScreenById(ctx, ids.SessionId, screenIdArg)
	if err != nil {
		return nil, err
	}
	return update, nil
}

func CdCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	ids, err := resolveIds(ctx, pk, R_Session|R_Window|R_Remote)
	if err != nil {
		return nil, fmt.Errorf("/cd error: %w", err)
	}
	newDir := firstArg(pk)
	cdPacket := packet.MakeCdPacket()
	cdPacket.ReqId = uuid.New().String()
	cdPacket.Dir = newDir
	localRemote := remote.GetRemoteById(ids.RemoteId)
	if localRemote == nil {
		return nil, fmt.Errorf("invalid remote, cannot execute command")
	}
	resp, err := localRemote.PacketRpc(ctx, cdPacket)
	if err != nil {
		return nil, err
	}
	fmt.Printf("GOT cd RESP: %v\n", resp)
	return nil, nil
}

func CommentCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	ids, err := resolveIds(ctx, pk, R_Session|R_Window)
	if err != nil {
		return nil, fmt.Errorf("/comment error: %w", err)
	}
	text := firstArg(pk)
	if strings.TrimSpace(text) == "" {
		return nil, fmt.Errorf("cannot post empty comment")
	}
	rtnLine, err := sstore.AddCommentLine(ctx, ids.SessionId, ids.WindowId, DefaultUserId, text)
	if err != nil {
		return nil, err
	}
	return sstore.LineUpdate{Line: rtnLine}, nil
}

func SessionCommand(ctx context.Context, pk *scpacket.FeCommandPacketType) (sstore.UpdatePacket, error) {
	if pk.MetaSubCmd == "open" || pk.MetaSubCmd == "new" {
		activate := resolveBool(pk.Kwargs["activate"], true)
		update, err := sstore.InsertSessionWithName(ctx, pk.Kwargs["name"], activate)
		if err != nil {
			return nil, err
		}
		return update, nil
	}
	if pk.MetaSubCmd != "" {
		return nil, fmt.Errorf("invalid /session subcommand '%s'", pk.MetaSubCmd)
	}
	firstArg := firstArg(pk)
	if firstArg == "" {
		return nil, fmt.Errorf("usage /session [session-name|session-id], no param specified")
	}
	sessionId, err := resolveSession(ctx, firstArg)
	if err != nil {
		return nil, err
	}
	return sstore.SessionUpdate{ActiveSessionId: sessionId}, nil
}