package main

import (
	"context"
	"crypto/sha256"
	"fmt"
	"log/slog"
	"os"
	"strings"
	"time"

	"git.intruders.space/public/opentimestamps"
	"git.intruders.space/public/opentimestamps/ots"
	"github.com/spf13/cobra"
)

// Default calendar servers
var defaultCalendars = []string{
	"https://alice.btc.calendar.opentimestamps.org",
	"https://bob.btc.calendar.opentimestamps.org",
	"https://finney.calendar.eternitywall.com",
}

var (
	// Create command flags
	createOutput       string
	createCalendarsStr string
	createTimeout      time.Duration
)

// createCmd represents the create command
var createCmd = &cobra.Command{
	Use:   "create [flags] <file>",
	Short: "Create a timestamp for a file",
	Long: `Create a timestamp for a file by submitting its digest to OpenTimestamps calendar servers.
The resulting timestamp is saved to a .ots file, which can later be verified or upgraded.`,
	Args: cobra.ExactArgs(1),
	Run:  runCreateCmd,
}

func init() {
	// Local flags for the create command
	createCmd.Flags().StringVarP(&createOutput, "output", "o", "", "Output filename (default: input filename with .ots extension)")
	createCmd.Flags().StringVar(&createCalendarsStr, "calendar", strings.Join(defaultCalendars, ","), "Comma-separated list of calendar server URLs")
	createCmd.Flags().DurationVar(&createTimeout, "timeout", 30*time.Second, "Timeout for calendar server connections")
}

func runCreateCmd(cmd *cobra.Command, args []string) {
	inputPath := args[0]

	// Determine output file path
	outputPath := createOutput
	if outputPath == "" {
		outputPath = inputPath + ".ots"
	}

	// Parse calendar servers
	calendars := strings.Split(createCalendarsStr, ",")
	if len(calendars) == 0 {
		calendars = defaultCalendars
	}

	// Read the input file
	fileData, err := os.ReadFile(inputPath)
	if err != nil {
		slog.Error("Failed to read input file", "file", inputPath, "error", err)
		os.Exit(1)
	}

	// Compute the file digest
	digest := sha256.Sum256(fileData)
	slog.Info("Computed file digest", "digest", fmt.Sprintf("%x", digest))

	// Create context with timeout
	ctx, cancel := context.WithTimeout(context.Background(), createTimeout)
	defer cancel()

	// Create timestamps using all calendar servers
	var sequences []ots.Sequence
	var errors []string

	for _, calendarURL := range calendars {
		calendarURL = strings.TrimSpace(calendarURL)
		if calendarURL == "" {
			continue
		}

		slog.Info("Submitting to calendar", "url", calendarURL)
		seq, err := opentimestamps.Stamp(ctx, calendarURL, digest)
		if err != nil {
			slog.Warn("Calendar submission failed", "url", calendarURL, "error", err)
			errors = append(errors, fmt.Sprintf("%s: %v", calendarURL, err))
			continue
		}

		sequences = append(sequences, seq)
		slog.Info("Calendar submission successful", "url", calendarURL)
	}

	if len(sequences) == 0 {
		slog.Error("All calendar submissions failed", "errors", errors)
		os.Exit(1)
	}

	// Create the timestamp file
	file := &ots.File{
		Digest:    digest[:],
		Sequences: sequences,
	}

	// Write the OTS file
	otsData := file.SerializeToFile()
	err = os.WriteFile(outputPath, otsData, 0644)
	if err != nil {
		slog.Error("Failed to write OTS file", "file", outputPath, "error", err)
		os.Exit(1)
	}

	slog.Info("Timestamp file created successfully",
		"file", outputPath,
		"timestamps", len(sequences),
		"size", len(otsData))

	// Print human-readable representation
	slog.Debug("Timestamp details", "info", file.Human(false))

	slog.Info("Timestamp creation complete",
		"status", "pending",
		"note", "Use 'ots upgrade' to upgrade this timestamp when it's confirmed in the Bitcoin blockchain")
}