package app

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

	"github.com/agentsphere/agent-mgr/internal/gitea"
	"github.com/agentsphere/agent-mgr/internal/provider"
	"github.com/agentsphere/agent-mgr/internal/store"
	"github.com/google/uuid"
)

type Service struct {
	store    *store.Store
	gitea    *gitea.Client
	registry *provider.Registry
	log      *slog.Logger
}

func NewService(s *store.Store, g *gitea.Client, r *provider.Registry, log *slog.Logger) *Service {
	return &Service{store: s, gitea: g, registry: r, log: log}
}

// CreateApp creates an app record, a Gitea repo, and starts the first build session.
func (svc *Service) CreateApp(ctx context.Context, name, description, providerName string, providerConfig json.RawMessage) (*store.App, *store.Session, error) {
	repoName := slugify(name)

	app, err := svc.store.CreateApp(ctx, name, description)
	if err != nil {
		return nil, nil, fmt.Errorf("create app: %w", err)
	}

	repo, err := svc.gitea.CreateRepo(ctx, repoName, description)
	if err != nil {
		_ = svc.store.DeleteApp(ctx, app.ID)
		return nil, nil, fmt.Errorf("create gitea repo: %w", err)
	}

	if err := svc.store.UpdateAppRepo(ctx, app.ID, repo.FullName[:strings.Index(repo.FullName, "/")], repo.Name); err != nil {
		return nil, nil, fmt.Errorf("update app repo: %w", err)
	}
	app.RepoOwner = repo.FullName[:strings.Index(repo.FullName, "/")]
	app.RepoName = repo.Name

	sess, err := svc.StartSession(ctx, app, description, providerName, providerConfig)
	if err != nil {
		return app, nil, fmt.Errorf("start initial session: %w", err)
	}

	return app, sess, nil
}

// StartSession creates a new session on an existing app and spawns the agent pod.
func (svc *Service) StartSession(ctx context.Context, app *store.App, prompt, providerName string, providerConfig json.RawMessage) (*store.Session, error) {
	if providerName == "" {
		providerName = "claude-code"
	}

	p, err := svc.registry.Get(providerName)
	if err != nil {
		return nil, err
	}

	sessID := uuid.New()
	branch := fmt.Sprintf("agent/%s", sessID.String()[:8])

	configBytes := providerConfig
	if configBytes == nil {
		configBytes = json.RawMessage(`{}`)
	}

	sess, err := svc.store.CreateSession(ctx, app.ID, providerName, prompt, branch, configBytes)
	if err != nil {
		return nil, fmt.Errorf("create session: %w", err)
	}
	// Override the auto-generated ID with our pre-generated one for branch consistency
	// (the DB generates its own UUID, but the branch name uses sessID)
	// We'll use the DB-generated ID going forward
	branch = fmt.Sprintf("agent/%s", sess.ID.String()[:8])
	_ = svc.store.UpdateSessionStatus(ctx, sess.ID, "pending")
	sess.Branch = branch

	cloneURL := svc.gitea.AuthCloneURL(app.RepoOwner, app.RepoName)

	systemPrompt := fmt.Sprintf("You are building an app called %q. The user's idea: %s\nCreate a complete, working application. When done, ensure all files are committed.", app.Name, app.Description)
	fullPrompt := prompt
	if prompt == app.Description {
		fullPrompt = systemPrompt
	}

	handle, err := p.CreateSession(ctx, provider.SessionConfig{
		SessionID:  sess.ID,
		AppName:    app.Name,
		RepoClone:  cloneURL,
		Branch:     branch,
		Prompt:     fullPrompt,
		Provider:   configBytes,
	})
	if err != nil {
		_ = svc.store.UpdateSessionStatus(ctx, sess.ID, "failed")
		return nil, fmt.Errorf("create agent session: %w", err)
	}

	_ = svc.store.UpdateSessionPod(ctx, sess.ID, handle.PodName)
	_ = svc.store.UpdateSessionStatus(ctx, sess.ID, "running")
	_ = svc.store.UpdateAppStatus(ctx, app.ID, "building")

	sess.PodName = handle.PodName
	sess.Status = "running"

	svc.log.Info("session started", "app", app.Name, "session", sess.ID, "pod", handle.PodName)
	return sess, nil
}

func (svc *Service) StopSession(ctx context.Context, sessID uuid.UUID) error {
	sess, err := svc.store.GetSession(ctx, sessID)
	if err != nil || sess == nil {
		return fmt.Errorf("session not found: %w", err)
	}

	p, err := svc.registry.Get(sess.Provider)
	if err != nil {
		return err
	}

	handle := &provider.SessionHandle{SessionID: sess.ID, PodName: sess.PodName}
	if err := p.StopSession(ctx, handle); err != nil {
		svc.log.Warn("failed to stop pod", "pod", sess.PodName, "err", err)
	}

	_ = svc.store.UpdateSessionStatus(ctx, sessID, "stopped")
	return nil
}

func (svc *Service) SendMessage(ctx context.Context, sessID uuid.UUID, msg string) error {
	sess, err := svc.store.GetSession(ctx, sessID)
	if err != nil || sess == nil {
		return fmt.Errorf("session not found")
	}
	if sess.Status != "running" {
		return fmt.Errorf("session not running (status: %s)", sess.Status)
	}

	p, err := svc.registry.Get(sess.Provider)
	if err != nil {
		return err
	}

	handle := &provider.SessionHandle{SessionID: sess.ID, PodName: sess.PodName}
	return p.SendMessage(ctx, handle, msg)
}

var nonAlphaNum = regexp.MustCompile(`[^a-z0-9-]+`)

func slugify(s string) string {
	s = strings.ToLower(strings.TrimSpace(s))
	s = nonAlphaNum.ReplaceAllString(s, "-")
	s = strings.Trim(s, "-")
	if len(s) > 50 {
		s = s[:50]
	}
	if s == "" {
		s = "app"
	}
	return s
}