package worker

import (
	"context"
	"encoding/json"
	"fmt"
	"log/slog"
	"strings"
	"time"

	"github.com/orchard9/rdev/internal/domain"
	"github.com/orchard9/rdev/internal/port"
)

// Verify event type constants for SSE streaming.
const (
	VerifyEventStarted   = "verify.started"
	VerifyEventCapturing = "verify.capturing"
	VerifyEventCaptured  = "verify.captured"
	VerifyEventCompleted = "verify.completed"
	VerifyEventFailed    = "verify.failed"
)

// VerifyExecutor handles WorkTaskTypeVerify tasks.
// It translates VerifySpec fields from the work task's Spec map,
// executes the Playwright capture script via kubectl exec,
// and returns a BuildResult for queue compatibility.
type VerifyExecutor struct {
	cmdExecutor port.CommandExecutor // kubectl exec wrapper
	streams     port.StreamPublisher // SSE stream publisher for real-time events
	logger      *slog.Logger
	namespace   string // Kubernetes namespace for the pod
	podName     string // Playwright pod name (e.g., "playwright-0")
}

// VerifyExecutorConfig holds configuration for the verify executor.
type VerifyExecutorConfig struct {
	Namespace string // Kubernetes namespace (e.g., "rdev")
	PodName   string // Playwright pod name (e.g., "playwright-0")
}

// NewVerifyExecutor creates a new verify executor.
func NewVerifyExecutor(
	cmdExecutor port.CommandExecutor,
	streams port.StreamPublisher,
	logger *slog.Logger,
	cfg *VerifyExecutorConfig,
) *VerifyExecutor {
	if logger == nil {
		logger = slog.Default()
	}
	if cfg == nil {
		cfg = &VerifyExecutorConfig{
			Namespace: "rdev",
			PodName:   "playwright-0",
		}
	}
	if cfg.Namespace == "" {
		cfg.Namespace = "rdev"
	}
	if cfg.PodName == "" {
		cfg.PodName = "playwright-0"
	}
	return &VerifyExecutor{
		cmdExecutor: cmdExecutor,
		streams:     streams,
		logger:      logger.With("component", "verify-executor"),
		namespace:   cfg.Namespace,
		podName:     cfg.PodName,
	}
}

// Execute runs a verify task by capturing screenshots/video of a URL.
func (v *VerifyExecutor) Execute(ctx context.Context, task *domain.WorkTask) *domain.BuildResult {
	start := time.Now()
	streamID := task.ID // Use task ID as stream ID for SSE

	// Publish verify.started event
	v.publishEvent(streamID, VerifyEventStarted, map[string]any{
		"task_id":    task.ID,
		"project_id": task.ProjectID,
		"started_at": start.Format(time.RFC3339),
	})

	// Parse VerifySpec from task.Spec
	spec, err := v.parseSpec(task.Spec)
	if err != nil {
		v.publishEvent(streamID, VerifyEventFailed, map[string]any{
			"task_id": task.ID,
			"error":   fmt.Sprintf("invalid verify spec: %v", err),
		})
		return &domain.BuildResult{
			Success:    false,
			Error:      fmt.Sprintf("invalid verify spec: %v", err),
			DurationMs: time.Since(start).Milliseconds(),
		}
	}

	// Apply defaults
	spec = spec.WithDefaults()

	// Build output directory using task ID for isolation
	outputDir := fmt.Sprintf("/captures/%s", task.ID)

	// Publish capturing event
	v.publishEvent(streamID, VerifyEventCapturing, map[string]any{
		"task_id":   task.ID,
		"url":       spec.URL,
		"viewports": spec.Viewports,
	})

	v.logger.Info("executing verify capture",
		"task_id", task.ID,
		"project_id", task.ProjectID,
		"url", spec.URL,
		"viewports", spec.Viewports,
		"pod", v.podName,
	)

	// Build capture command
	cmdArgs := v.buildCaptureCommand(spec, outputDir)

	// Execute via CommandExecutor
	captureOutput, err := v.executeCapture(ctx, task.ID, cmdArgs)
	if err != nil {
		v.publishEvent(streamID, VerifyEventFailed, map[string]any{
			"task_id":     task.ID,
			"error":       fmt.Sprintf("capture execution failed: %v", err),
			"duration_ms": time.Since(start).Milliseconds(),
		})
		v.closeStream(ctx, streamID)
		return &domain.BuildResult{
			Success:    false,
			Error:      fmt.Sprintf("capture execution failed: %v", err),
			DurationMs: time.Since(start).Milliseconds(),
		}
	}

	// Parse JSON manifest from stdout
	verifyResult, err := v.parseManifest(captureOutput)
	if err != nil {
		v.publishEvent(streamID, VerifyEventFailed, map[string]any{
			"task_id":     task.ID,
			"error":       fmt.Sprintf("failed to parse capture manifest: %v", err),
			"duration_ms": time.Since(start).Milliseconds(),
		})
		v.closeStream(ctx, streamID)
		return &domain.BuildResult{
			Success:    false,
			Error:      fmt.Sprintf("failed to parse capture manifest: %v", err),
			DurationMs: time.Since(start).Milliseconds(),
		}
	}

	verifyResult.Success = true
	verifyResult.DurationMs = time.Since(start).Milliseconds()

	// Publish captured event
	v.publishEvent(streamID, VerifyEventCaptured, map[string]any{
		"task_id":     task.ID,
		"screenshots": verifyResult.Screenshots,
		"video":       verifyResult.Video,
	})

	// Publish completion event
	v.publishEvent(streamID, VerifyEventCompleted, map[string]any{
		"task_id":     task.ID,
		"success":     true,
		"screenshots": verifyResult.Screenshots,
		"video":       verifyResult.Video,
		"duration_ms": verifyResult.DurationMs,
	})
	v.closeStream(ctx, streamID)

	// Convert to BuildResult for queue compatibility
	return verifyResult.ToBuildResult()
}

// buildCaptureCommand constructs the node command arguments for capture.js.
func (v *VerifyExecutor) buildCaptureCommand(spec *domain.VerifySpec, outputDir string) []string {
	args := []string{
		"node", "/scripts/capture.js",
		"--url=" + spec.URL,
		"--output=" + outputDir,
		"--viewports=" + strings.Join(spec.Viewports, ","),
	}

	if spec.WaitFor != "" {
		args = append(args, "--wait-for="+spec.WaitFor)
	}

	if spec.FullPage {
		args = append(args, "--full-page=true")
	}

	if spec.Video {
		args = append(args, "--video=true")
	}

	return args
}

// executeCapture runs the capture command in the Playwright pod.
func (v *VerifyExecutor) executeCapture(ctx context.Context, taskID string, cmdArgs []string) (string, error) {
	// Create a command to execute
	cmd := &domain.Command{
		ID:        domain.CommandID(fmt.Sprintf("verify-%s", taskID)),
		ProjectID: "", // Verify tasks aren't project-specific
		Type:      domain.CommandTypeShell,
		Args:      cmdArgs,
		StartedAt: time.Now(),
	}

	var outputBuilder strings.Builder

	// Execute the command and capture output
	result, err := v.cmdExecutor.Execute(ctx, cmd, v.podName, func(line domain.OutputLine) {
		// Capture all output for parsing
		if line.Stream == "stdout" {
			outputBuilder.WriteString(line.Line)
			outputBuilder.WriteString("\n")
		}
	})
	if err != nil {
		return "", fmt.Errorf("kubectl exec failed: %w", err)
	}

	if !result.Success() {
		return "", fmt.Errorf("capture script failed with exit code %d", result.ExitCode)
	}

	return outputBuilder.String(), nil
}

// parseManifest parses the JSON capture manifest from the script output.
func (v *VerifyExecutor) parseManifest(output string) (*domain.VerifyResult, error) {
	// The capture script outputs JSON to stdout
	// Find the JSON line (last non-empty line)
	lines := strings.Split(strings.TrimSpace(output), "\n")
	if len(lines) == 0 {
		return nil, fmt.Errorf("no output from capture script")
	}

	jsonLine := lines[len(lines)-1]

	var manifest struct {
		Screenshots map[string]string `json:"screenshots"`
		Video       string            `json:"video,omitempty"`
	}

	if err := json.Unmarshal([]byte(jsonLine), &manifest); err != nil {
		return nil, fmt.Errorf("invalid JSON manifest: %w", err)
	}

	return &domain.VerifyResult{
		Screenshots: manifest.Screenshots,
		Video:       manifest.Video,
	}, nil
}

// parseSpec extracts typed VerifySpec fields from the generic map[string]any.
func (v *VerifyExecutor) parseSpec(spec map[string]any) (*domain.VerifySpec, error) {
	url, _ := spec["url"].(string)
	if url == "" {
		return nil, domain.ErrVerifyURLRequired
	}

	vs := &domain.VerifySpec{
		URL: url,
	}

	// Parse optional fields
	if viewports, ok := spec["viewports"].([]any); ok {
		for _, vp := range viewports {
			if s, ok := vp.(string); ok {
				vs.Viewports = append(vs.Viewports, s)
			}
		}
	}

	if waitFor, ok := spec["wait_for"].(string); ok {
		vs.WaitFor = waitFor
	}

	if waitTimeout, ok := spec["wait_timeout"].(float64); ok {
		vs.WaitTimeout = int(waitTimeout)
	}

	if fullPage, ok := spec["full_page"].(bool); ok {
		vs.FullPage = fullPage
	}

	if video, ok := spec["video"].(bool); ok {
		vs.Video = video
	}

	if evaluate, ok := spec["evaluate"].(bool); ok {
		vs.Evaluate = evaluate
	}

	if prompt, ok := spec["prompt"].(string); ok {
		vs.Prompt = prompt
	}

	if callbackURL, ok := spec["callback_url"].(string); ok {
		vs.CallbackURL = callbackURL
	}

	// Validate the spec
	if err := vs.Validate(); err != nil {
		return nil, err
	}

	return vs, nil
}

// publishEvent publishes an event to the SSE stream if a stream publisher is configured.
func (v *VerifyExecutor) publishEvent(streamID, eventType string, data map[string]any) {
	if v.streams == nil {
		return
	}
	v.streams.Publish(streamID, port.StreamEvent{
		Type: eventType,
		Data: data,
	})
}

// closeStream closes the stream after a delay to allow clients to receive final events.
func (v *VerifyExecutor) closeStream(ctx context.Context, streamID string) {
	if v.streams == nil {
		return
	}
	// Close stream after a short delay to ensure final events are delivered.
	go func() {
		select {
		case <-ctx.Done():
			v.streams.Close(streamID)
		case <-time.After(streamCloseDelay):
			v.streams.Close(streamID)
		}
	}()
}