package cmd

import (
	"crypto/rand"
	"encoding/base32"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"github.com/steveyegge/gastown/internal/beads"
	"github.com/steveyegge/gastown/internal/style"
	"github.com/steveyegge/gastown/internal/workspace"
)

// slingGenerateShortID generates a short random ID (5 lowercase chars).
func slingGenerateShortID() string {
	b := make([]byte, 3)
	_, _ = rand.Read(b)
	return strings.ToLower(base32.StdEncoding.EncodeToString(b)[:5])
}

// isTrackedByConvoy checks if an issue is already being tracked by a convoy.
// Returns the convoy ID if tracked, empty string otherwise.
func isTrackedByConvoy(beadID string) string {
	townRoot, err := workspace.FindFromCwd()
	if err != nil {
		return ""
	}

	// Query town beads for any convoy that tracks this issue
	// Convoys use "tracks" dependency type: convoy -> tracked issue
	townBeads := filepath.Join(townRoot, ".beads")
	dbPath := filepath.Join(townBeads, "beads.db")

	// Query dependencies where this bead is being tracked
	// Also check for external reference format: external:rig:issue-id
	query := fmt.Sprintf(`
		SELECT d.issue_id
		FROM dependencies d
		JOIN issues i ON d.issue_id = i.id
		WHERE d.type = 'tracks'
		AND i.issue_type = 'convoy'
		AND (d.depends_on_id = '%s' OR d.depends_on_id LIKE '%%:%s')
		LIMIT 1
	`, beadID, beadID)

	queryCmd := exec.Command("sqlite3", dbPath, query)
	out, err := queryCmd.Output()
	if err != nil {
		return ""
	}

	convoyID := strings.TrimSpace(string(out))
	return convoyID
}

// filterEnvExcluding returns a copy of the environment with specified keys removed.
// This is used to prevent rig-specific environment variables from affecting
// commands that need to run in a different context (e.g., HQ beads).
func filterEnvExcluding(env []string, excludeKeys ...string) []string {
	result := make([]string, 0, len(env))
	for _, e := range env {
		exclude := false
		for _, key := range excludeKeys {
			if strings.HasPrefix(e, key+"=") {
				exclude = true
				break
			}
		}
		if !exclude {
			result = append(result, e)
		}
	}
	return result
}

// createAutoConvoy creates an auto-convoy for a single issue and tracks it.
// Returns the created convoy ID.
func createAutoConvoy(beadID, beadTitle string) (string, error) {
	townRoot, err := workspace.FindFromCwd()
	if err != nil {
		return "", fmt.Errorf("finding town root: %w", err)
	}

	townBeads := filepath.Join(townRoot, ".beads")

	// Generate convoy ID with hq-cv- prefix for visual distinction
	// The hq-cv- prefix is registered in routes during gt install
	convoyID := fmt.Sprintf("hq-cv-%s", slingGenerateShortID())

	// Create convoy with title "Work: <issue-title>"
	convoyTitle := fmt.Sprintf("Work: %s", beadTitle)
	description := fmt.Sprintf("Auto-created convoy tracking %s", beadID)

	createArgs := []string{
		"create",
		"--type=convoy",
		"--id=" + convoyID,
		"--title=" + convoyTitle,
		"--description=" + description,
	}
	if beads.NeedsForceForID(convoyID) {
		createArgs = append(createArgs, "--force")
	}

	// Clear BEADS_DIR so bd discovers the database from townBeads directory
	// instead of using the rig's beads (which has a different prefix)
	cleanEnv := filterEnvExcluding(os.Environ(), "BEADS_DIR")

	createCmd := exec.Command("bd", append([]string{"--no-daemon"}, createArgs...)...)
	createCmd.Dir = townBeads
	createCmd.Env = cleanEnv
	createCmd.Stderr = os.Stderr

	if err := createCmd.Run(); err != nil {
		return "", fmt.Errorf("creating convoy: %w", err)
	}

	// Add tracking relation: convoy tracks the issue
	trackBeadID := formatTrackBeadID(beadID)
	depArgs := []string{"--no-daemon", "dep", "add", convoyID, trackBeadID, "--type=tracks"}
	depCmd := exec.Command("bd", depArgs...)
	depCmd.Dir = townBeads
	depCmd.Env = cleanEnv
	depCmd.Stderr = os.Stderr

	if err := depCmd.Run(); err != nil {
		// Convoy was created but tracking failed - log warning but continue
		fmt.Printf("%s Could not add tracking relation: %v\n", style.Dim.Render("Warning:"), err)
	}

	return convoyID, nil
}

// formatTrackBeadID formats a bead ID for use in convoy tracking dependencies.
// Cross-rig beads (non-hq- prefixed) are formatted as external references
// so the bd tool can resolve them when running from HQ context.
//
// Examples:
//   - "hq-abc123" -> "hq-abc123" (HQ beads unchanged)
//   - "gt-mol-xyz" -> "external:gt-mol:gt-mol-xyz"
//   - "beads-task-123" -> "external:beads-task:beads-task-123"
func formatTrackBeadID(beadID string) string {
	if strings.HasPrefix(beadID, "hq-") {
		return beadID
	}
	parts := strings.SplitN(beadID, "-", 3)
	if len(parts) >= 2 {
		rigPrefix := parts[0] + "-" + parts[1]
		return fmt.Sprintf("external:%s:%s", rigPrefix, beadID)
	}
	// Fallback for malformed IDs (single segment)
	return beadID
}