package cmd

import (
	"context"
	"fmt"
	"log"
	"os"
	"os/signal"
	"strings"
	"syscall"
	"time"

	"github.com/fatih/color"
	"github.com/spf13/cobra"
	"github.com/torrentclaw/unarr/internal/agent"
	"github.com/torrentclaw/unarr/internal/engine"
	"github.com/torrentclaw/unarr/internal/parser"
)

// downloadDeps agrupa las funciones constructoras usadas por runDownload.
// Pueden sobreescribirse en tests para inyectar mocks.
type downloadDeps struct {
	newTorrentDl   func(cfg engine.TorrentConfig) (engine.Downloader, error)
	newDebridDl    func() engine.Downloader
	newAgentClient func(url, key, ua string) *agent.Client
	newManager     func(cfg engine.ManagerConfig, reporter *engine.ProgressReporter, dls ...engine.Downloader) *engine.Manager
}

var defaultDownloadDeps = downloadDeps{
	newTorrentDl: func(cfg engine.TorrentConfig) (engine.Downloader, error) {
		return engine.NewTorrentDownloader(cfg)
	},
	newDebridDl: func() engine.Downloader {
		return engine.NewDebridDownloader()
	},
	newAgentClient: agent.NewClient,
	newManager:     engine.NewManager,
}

func newDownloadCmd() *cobra.Command {
	var method string

	cmd := &cobra.Command{
		Use:   "download <info_hash|magnet>",
		Short: "Download a torrent (one-shot, no daemon needed)",
		Long: `Download a specific torrent by info hash or magnet link.

This is a standalone download that does not require the daemon to be running.
Useful for quick one-off downloads. The file is saved to your configured
download directory. Press Ctrl+C to cancel.

For managed downloads (queue, progress tracking, web dashboard), use the
daemon instead: 'unarr start'.`,
		Example: `  unarr download abc123def456abc123def456abc123def456abc1
  unarr download "magnet:?xt=urn:btih:..." --method torrent`,
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			return runDownload(args[0], method)
		},
	}

	cmd.Flags().StringVar(&method, "method", "torrent", "download method: torrent, debrid, usenet")
	cmd.RegisterFlagCompletionFunc("method", func(cmd *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
		return []string{"torrent\tBitTorrent P2P", "debrid\tReal-Debrid / AllDebrid", "usenet\tUsenet (requires Pro)"}, cobra.ShellCompDirectiveNoFileComp
	})

	return cmd
}

func runDownload(input, method string) error {
	return runDownloadWithDeps(input, method, defaultDownloadDeps)
}

func runDownloadWithDeps(input, method string, deps downloadDeps) error {
	cfg := loadConfig()
	bold := color.New(color.Bold)
	green := color.New(color.FgGreen)

	// Parse input
	parsed := parser.Parse(input)
	infoHash := parsed.InfoHash
	if infoHash == "" {
		// Treat as info hash directly if 40 hex chars
		input = strings.TrimSpace(input)
		if len(input) == 40 {
			infoHash = strings.ToLower(input)
		} else {
			return fmt.Errorf("invalid input: provide a 40-char info hash or magnet URI")
		}
	}
	if len(infoHash) < 40 {
		return fmt.Errorf("invalid info hash: expected 40 characters, got %d", len(infoHash))
	}

	outputDir := cfg.Download.Dir
	if outputDir == "" {
		home, _ := os.UserHomeDir()
		outputDir = home
	}

	if err := os.MkdirAll(outputDir, 0o755); err != nil {
		return fmt.Errorf("create output dir: %w", err)
	}

	fmt.Println()
	bold.Printf("  Downloading %s...\n", infoHash[:16]+"...")
	fmt.Printf("  Method: %s | Output: %s\n", method, outputDir)
	fmt.Println()

	// Create torrent downloader
	torrentDl, err := deps.newTorrentDl(engine.TorrentConfig{
		DataDir:         outputDir,
		MetadataTimeout: 15 * time.Minute,
		StallTimeout:    10 * time.Minute,
		MaxTimeout:      0, // unlimited
		SeedEnabled:     false,
	})
	if err != nil {
		return fmt.Errorf("create downloader: %w", err)
	}

	// Create a dummy reporter (no API reporting for one-shot)
	reporter := engine.NewProgressReporter(
		deps.newAgentClient(cfg.Auth.APIURL, cfg.Auth.APIKey, "unarr/"+Version),
		5*time.Second,
	)

	debridDl := deps.newDebridDl()

	manager := deps.newManager(engine.ManagerConfig{
		MaxConcurrent: 1,
		OutputDir:     outputDir,
		Organize: engine.OrganizeConfig{
			Enabled:    cfg.Organize.Enabled,
			MoviesDir:  cfg.Organize.MoviesDir,
			TVShowsDir: cfg.Organize.TVShowsDir,
			OutputDir:  outputDir,
		},
	}, reporter, torrentDl, debridDl)

	ctx, cancel := context.WithCancel(context.Background())
	defer cancel()

	// Signal handling
	sigCh := make(chan os.Signal, 1)
	signal.Notify(sigCh, syscall.SIGINT, syscall.SIGTERM)
	go func() {
		<-sigCh
		fmt.Println("\n  Cancelling download...")
		cancel()
	}()

	// Start progress reporter
	go reporter.Run(ctx)

	// Submit task
	task := agent.Task{
		ID:              "oneshot-" + infoHash[:8],
		InfoHash:        infoHash,
		Title:           parsed.Name,
		PreferredMethod: method,
	}

	manager.Submit(ctx, task)
	manager.Wait()

	// Check result
	active := manager.ActiveTasks()
	if len(active) == 0 {
		green.Println("  Download complete!")
	} else {
		for _, t := range active {
			if t.GetStatus() == engine.StatusFailed {
				return fmt.Errorf("download failed: %s", t.ErrorMessage)
			}
		}
	}

	// Shutdown
	shutdownCtx, shutdownCancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer shutdownCancel()
	manager.Shutdown(shutdownCtx)
	cancel()

	log.SetOutput(os.Stderr) // suppress cleanup logs
	fmt.Println()

	return nil
}