package main

import (
	"context"
	"errors"
	"flag"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
	"git.fabledsword.com/bvandeusen/minstrel/internal/config"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db"
	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrconfig"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrrequests"
	"git.fabledsword.com/bvandeusen/minstrel/internal/logging"
	"git.fabledsword.com/bvandeusen/minstrel/internal/scrobble"
	"git.fabledsword.com/bvandeusen/minstrel/internal/scrobble/listenbrainz"
	"git.fabledsword.com/bvandeusen/minstrel/internal/server"
	"git.fabledsword.com/bvandeusen/minstrel/internal/similarity"
	"git.fabledsword.com/bvandeusen/minstrel/internal/subsonic"
)

func main() {
	if err := run(); err != nil {
		fmt.Fprintf(os.Stderr, "minstrel: %v\n", err)
		os.Exit(1)
	}
}

func run() error {
	configPath := flag.String("config", os.Getenv("MINSTREL_CONFIG"), "path to YAML config file")
	flag.Parse()

	cfg, err := config.Load(*configPath)
	if err != nil {
		return fmt.Errorf("load config: %w", err)
	}

	logger, err := logging.New(os.Stdout, cfg.Log.Level, cfg.Log.Format)
	if err != nil {
		return fmt.Errorf("init logger: %w", err)
	}

	logger.Info("minstrel starting",
		"address", cfg.Server.Address,
		"log_level", cfg.Log.Level,
		"log_format", cfg.Log.Format,
	)

	ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
	defer stop()

	if err := db.Migrate(cfg.Database.URL, logger); err != nil {
		return fmt.Errorf("migrate: %w", err)
	}

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

	if err := auth.Bootstrap(ctx, pool, cfg.Auth.AdminBootstrap, logger); err != nil {
		return fmt.Errorf("bootstrap admin: %w", err)
	}

	scanner := library.New(pool, logger, cfg.Library.ScanPaths)
	if cfg.Library.ScanOnStartup && len(cfg.Library.ScanPaths) > 0 {
		go func() {
			if _, err := scanner.Scan(ctx); err != nil {
				logger.Error("startup scan failed", "err", err)
			}
		}()
	}

	// Start the ListenBrainz scrobble worker. Per spec §M4a, runs every 30s
	// and drains up to 50 pending rows per tick. Per-user gating happens
	// inside the worker (rows from disabled users are skipped).
	scrobbleWorker := scrobble.NewWorker(pool, listenbrainz.NewClient(), logger.With("component", "scrobble"))
	go scrobbleWorker.Run(ctx)

	// Start the similarity ingest worker. Per spec §M4b, runs every 1h, drains
	// up to 5 played tracks + 5 played artists per tick, weekly re-fetch cap
	// per row. Public LB endpoints — no token required.
	similarityWorker := similarity.NewWorker(pool, listenbrainz.NewClient(), logger.With("component", "similarity"))
	go similarityWorker.Run(ctx)

	// Start the Lidarr reconciler worker. Per spec §M5a, polls pending Lidarr
	// import requests and reconciles them against the library. Short-circuits
	// to no-op when lidarr_config.enabled = false.
	lidarrCfg := lidarrconfig.New(pool)
	lidarrReconciler := lidarrrequests.NewReconciler(pool, lidarrCfg, logger.With("component", "lidarr"))
	go lidarrReconciler.Run(ctx)

	// Ensure DataDir exists before any service tries to write into it.
	// Best-effort: log + continue on failure; the playlist cover writer
	// will surface a clearer error at first use.
	if cfg.Storage.DataDir != "" {
		if err := os.MkdirAll(cfg.Storage.DataDir, 0o755); err != nil {
			logger.Warn("data_dir create failed; cached artifacts may not persist",
				"path", cfg.Storage.DataDir, "err", err)
		}
	}

	srv := server.New(logger, pool, scanner, subsonic.Config{
		AllowPlaintextPassword: cfg.Subsonic.AllowPlaintextPassword,
	}, cfg.Events, cfg.Recommendation, cfg.Storage.DataDir, cfg.Branding)
	httpServer := &http.Server{
		Addr:              cfg.Server.Address,
		Handler:           srv.Router(),
		ReadHeaderTimeout: 10 * time.Second,
	}

	errCh := make(chan error, 1)
	go func() {
		logger.Info("listening", "address", cfg.Server.Address)
		if err := httpServer.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			errCh <- err
		}
		close(errCh)
	}()

	select {
	case <-ctx.Done():
		logger.Info("shutdown signal received")
	case err := <-errCh:
		if err != nil {
			return fmt.Errorf("server: %w", err)
		}
	}

	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if err := httpServer.Shutdown(shutdownCtx); err != nil {
		return fmt.Errorf("shutdown: %w", err)
	}
	logger.Info("minstrel stopped")
	return nil
}
