package lifecycle

import (
	"context"
	"fmt"
	"time"

	"go.uber.org/zap"

	"github.com/kandev/kandev/internal/agent/agents"
	"github.com/kandev/kandev/internal/agent/executor"
	agentctl "github.com/kandev/kandev/internal/agentctl/client"
	"github.com/kandev/kandev/internal/agentctl/server/process"
	"github.com/kandev/kandev/internal/common/logger"
)

// StandaloneExecutor implements Runtime for standalone agentctl execution.
// In this mode, a single agentctl control server manages multiple agent instances.
type StandaloneExecutor struct {
	ctl               *agentctl.ControlClient
	host              string
	port              int
	authToken         string // per-launch auth token from launcher
	logger            *logger.Logger
	interactiveRunner *process.InteractiveRunner
}

// NewStandaloneExecutor creates a new standalone runtime.
func NewStandaloneExecutor(ctl *agentctl.ControlClient, host string, port int, log *logger.Logger) *StandaloneExecutor {
	return &StandaloneExecutor{
		ctl:    ctl,
		host:   host,
		port:   port,
		logger: log.WithFields(zap.String("runtime", "standalone")),
	}
}

// SetAuthToken sets the per-launch auth token for authenticating instance clients.
func (r *StandaloneExecutor) SetAuthToken(token string) {
	r.authToken = token
}

func (r *StandaloneExecutor) Name() executor.Name {
	return executor.NameStandalone
}

func (r *StandaloneExecutor) HealthCheck(ctx context.Context) error {
	return r.ctl.Health(ctx)
}

func (r *StandaloneExecutor) waitForReady(ctx context.Context) error {
	if err := r.ctl.Health(ctx); err == nil {
		return nil
	}

	waitCtx := ctx
	if _, hasDeadline := ctx.Deadline(); !hasDeadline {
		var cancel context.CancelFunc
		waitCtx, cancel = context.WithTimeout(ctx, 10*time.Second)
		defer cancel()
	}

	ticker := time.NewTicker(500 * time.Millisecond)
	defer ticker.Stop()

	for {
		select {
		case <-waitCtx.Done():
			return fmt.Errorf("agentctl not ready: %w", waitCtx.Err())
		case <-ticker.C:
			if err := r.ctl.Health(waitCtx); err == nil {
				return nil
			}
		}
	}
}

func (r *StandaloneExecutor) CreateInstance(ctx context.Context, req *ExecutorCreateRequest) (*ExecutorInstance, error) {
	if err := r.waitForReady(ctx); err != nil {
		return nil, err
	}

	// Build environment variables
	env := req.Env
	if env == nil {
		env = make(map[string]string)
	}
	env["KANDEV_TASK_ID"] = req.TaskID
	env["KANDEV_SESSION_ID"] = req.SessionID

	// Create instance via control API
	// Agent command is NOT set - workspace access only. Agent is started explicitly via agentctl client.
	agentType := ""
	if req.AgentConfig != nil {
		agentType = req.AgentConfig.ID()
	}
	disableAskQuestion := agents.IsPassthroughOnly(req.AgentConfig)
	assumeMcpSse := false
	if req.AgentConfig != nil {
		if rt := req.AgentConfig.Runtime(); rt != nil {
			assumeMcpSse = rt.AssumeMcpSse
		}
	}

	createReq := &agentctl.CreateInstanceRequest{
		ID:                 req.InstanceID,
		WorkspacePath:      req.WorkspacePath,
		AgentCommand:       "", // Agent command set via Configure endpoint
		Protocol:           req.Protocol,
		AgentType:          agentType,
		Env:                env,
		AutoStart:          false,
		McpServers:         req.McpServers,
		SessionID:          req.SessionID,
		TaskID:             req.TaskID,
		DisableAskQuestion: disableAskQuestion,
		AssumeMcpSse:       assumeMcpSse,
		McpMode:            req.McpMode,
	}

	r.logger.Info("CreateInstance: sending request to agentctl",
		zap.String("instance_id", req.InstanceID),
		zap.String("req_protocol", req.Protocol),
		zap.String("createReq_protocol", createReq.Protocol))

	resp, err := r.ctl.CreateInstance(ctx, createReq)
	if err != nil {
		return nil, fmt.Errorf("failed to create standalone instance: %w", err)
	}

	// Create agentctl client pointing to the instance port
	client := agentctl.NewClient(r.host, resp.Port, r.logger,
		agentctl.WithExecutionID(req.InstanceID),
		agentctl.WithSessionID(req.SessionID),
		agentctl.WithAuthToken(r.authToken))

	// Extract runtime-specific values from metadata
	worktreeID := getMetadataString(req.Metadata, MetadataKeyWorktreeID)
	worktreeBranch := getMetadataString(req.Metadata, MetadataKeyWorktreeBranch)

	// Build metadata
	metadata := make(map[string]interface{})
	metadata["standalone_port"] = resp.Port
	if worktreeID != "" {
		metadata["worktree_id"] = worktreeID
		metadata["worktree_path"] = req.WorkspacePath
		metadata["worktree_branch"] = worktreeBranch
	}

	r.logger.Debug("standalone instance created",
		zap.String("instance_id", req.InstanceID),
		zap.Int("port", resp.Port),
		zap.String("workspace", req.WorkspacePath))

	return &ExecutorInstance{
		InstanceID:           req.InstanceID,
		TaskID:               req.TaskID,
		SessionID:            req.SessionID,
		RuntimeName:          string(r.Name()),
		Client:               client,
		StandaloneInstanceID: resp.ID,
		StandalonePort:       resp.Port,
		WorkspacePath:        req.WorkspacePath,
		Metadata:             metadata,
	}, nil
}

func (r *StandaloneExecutor) StopInstance(ctx context.Context, instance *ExecutorInstance, force bool) error {
	if instance.StandaloneInstanceID == "" {
		return nil // No standalone instance to stop
	}

	if err := r.ctl.DeleteInstance(ctx, instance.StandaloneInstanceID); err != nil {
		return fmt.Errorf("failed to stop standalone instance: %w", err)
	}

	return nil
}

func (r *StandaloneExecutor) RecoverInstances(ctx context.Context) ([]*ExecutorInstance, error) {
	// Standalone instances are not persisted - they are transient processes
	// managed by agentctl. Session resume will restart them as needed.
	return nil, nil
}

// SetInteractiveRunner sets the interactive runner for passthrough mode.
func (r *StandaloneExecutor) SetInteractiveRunner(runner *process.InteractiveRunner) {
	r.interactiveRunner = runner
}

// GetInteractiveRunner returns the interactive runner for passthrough mode.
func (r *StandaloneExecutor) GetInteractiveRunner() *process.InteractiveRunner {
	return r.interactiveRunner
}

func (r *StandaloneExecutor) RequiresCloneURL() bool          { return false }
func (r *StandaloneExecutor) ShouldApplyPreferredShell() bool { return true }
func (r *StandaloneExecutor) IsAlwaysResumable() bool         { return false }