package app

import (
	"context"
	"errors"
	"fmt"
	"log/slog"
	"net/http"
	"os"
	"time"

	"github.com/tim/cairnquire/apps/server/internal/config"
	"github.com/tim/cairnquire/apps/server/internal/database"
	"github.com/tim/cairnquire/apps/server/internal/docs"
	"github.com/tim/cairnquire/apps/server/internal/httpserver"
	"github.com/tim/cairnquire/apps/server/internal/markdown"
	"github.com/tim/cairnquire/apps/server/internal/realtime"
	"github.com/tim/cairnquire/apps/server/internal/store"
	"github.com/tim/cairnquire/apps/server/internal/sync"
)

type App struct {
	cfg    config.Config
	logger *slog.Logger
	db     database.DB
	docs   *docs.Service
	hub    *realtime.Hub
	server *http.Server
}

func New(ctx context.Context, cfg config.Config, logger *slog.Logger) (*App, error) {
	if err := os.MkdirAll(cfg.Content.SourceDir, 0o755); err != nil {
		return nil, fmt.Errorf("create content source dir: %w", err)
	}

	contentStore, err := store.New(cfg.Content.StoreDir)
	if err != nil {
		return nil, fmt.Errorf("create content store: %w", err)
	}

	db, err := database.Open(ctx, cfg.Database)
	if err != nil {
		return nil, fmt.Errorf("open database: %w", err)
	}

	if err := database.ApplyMigrations(ctx, db.SQL()); err != nil {
		return nil, fmt.Errorf("apply migrations: %w", err)
	}

	renderer := markdown.NewRenderer()
	repo := docs.NewRepository(db.SQL())
	service := docs.NewService(cfg.Content.SourceDir, contentStore, renderer, repo, logger)
	hub := realtime.NewHub(logger)
	service.OnChange(func(change docs.DocumentChange) {
		hub.Broadcast(realtime.Event{Type: "document_version", Data: change})
	})

	if _, err := service.SyncSourceDir(ctx); err != nil {
		logger.Warn("initial content sync failed", "error", err)
	}

	syncRepo := sync.NewRepository(db.SQL())
	syncService := sync.NewService(syncRepo, service, contentStore, cfg.Content.SourceDir, logger)

	handler, err := httpserver.New(httpserver.Dependencies{
		Config:       cfg,
		Logger:       logger,
		Documents:    service,
		Repository:   repo,
		ContentStore: contentStore,
		Hub:          hub,
		SyncService:  syncService,
		SyncRepo:     syncRepo,
	})
	if err != nil {
		return nil, fmt.Errorf("build http handler: %w", err)
	}

	server := &http.Server{
		Addr:              cfg.Server.Addr,
		Handler:           handler,
		ReadHeaderTimeout: 5 * time.Second,
		ReadTimeout:       15 * time.Second,
		WriteTimeout:      30 * time.Second,
		IdleTimeout:       60 * time.Second,
	}

	return &App{
		cfg:    cfg,
		logger: logger,
		db:     db,
		docs:   service,
		hub:    hub,
		server: server,
	}, nil
}

func (a *App) Run(ctx context.Context) error {
	go a.watchDocuments(ctx)
	go a.syncPoll(ctx)

	go func() {
		<-ctx.Done()
		shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
		defer cancel()

		if err := a.server.Shutdown(shutdownCtx); err != nil && !errors.Is(err, http.ErrServerClosed) {
			a.logger.Error("shutdown server", "error", err)
		}
	}()

	a.logger.Info("starting server", "addr", a.cfg.Server.Addr)
	return a.server.ListenAndServe()
}

func (a *App) watchDocuments(ctx context.Context) {
	watcher, err := NewFileWatcher(a.cfg.Content.SourceDir, a.logger)
	if err != nil {
		a.logger.Warn("file watcher failed, falling back to polling only", "error", err)
		<-ctx.Done()
		return
	}

	watcher.SetOnChange(func(path string) {
		if _, err := a.docs.SyncSourceDir(ctx); err != nil {
			a.logger.Warn("document sync failed", "error", err)
		} else {
			a.logger.Debug("document synced", "path", path)
		}
	})

	watcher.Run(ctx)
}

func (a *App) syncPoll(ctx context.Context) {
	ticker := time.NewTicker(30 * time.Second)
	defer ticker.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			if _, err := a.docs.SyncSourceDir(ctx); err != nil {
				a.logger.Warn("document sync poll failed", "error", err)
			}
		}
	}
}

func (a *App) Close() error {
	return a.db.Close()
}