package cmd

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"os/exec"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/spf13/cobra"
	"github.com/steveyegge/gastown/internal/style"
)

// Goal command flags
var (
	goalsJSON        bool
	goalsStatus      string
	goalsPriority    string
	goalsIncludeWisp bool
)

var goalsCmd = &cobra.Command{
	Use:     "goals [goal-id]",
	GroupID: GroupWork,
	Short:   "View strategic goals (epics) with staleness indicators",
	Long: `View strategic goals (epics) across the workspace.

Goals are high-level objectives that organize related work items.
This command shows goals with staleness indicators to help identify
stale or neglected strategic initiatives.

Staleness indicators:
  🟢 active: movement in last hour
  🟡 stale:  no movement for 1+ hours
  🔴 stuck:  no movement for 4+ hours

Goals are sorted by staleness × priority (highest attention needed first).

Examples:
  gt goals              # List all open goals
  gt goals --json       # Output as JSON
  gt goals --status=all # Show all goals including closed
  gt goals gt-abc       # Show details for a specific goal`,
	RunE: runGoals,
}

func init() {
	goalsCmd.Flags().BoolVar(&goalsJSON, "json", false, "Output as JSON")
	goalsCmd.Flags().StringVar(&goalsStatus, "status", "open", "Filter by status (open, closed, all)")
	goalsCmd.Flags().StringVar(&goalsPriority, "priority", "", "Filter by priority (e.g., P0, P1, P2)")
	goalsCmd.Flags().BoolVar(&goalsIncludeWisp, "include-wisp", false, "Include transient wisp molecules (normally hidden)")
	rootCmd.AddCommand(goalsCmd)
}

func runGoals(cmd *cobra.Command, args []string) error {
	// If arg provided, show specific goal
	if len(args) > 0 {
		goalID := args[0]
		return showGoal(goalID)
	}

	// Otherwise list all goals
	return listGoals()
}

// goalInfo holds computed goal data for display and sorting.
type goalInfo struct {
	ID            string    `json:"id"`
	Title         string    `json:"title"`
	Status        string    `json:"status"`
	Priority      int       `json:"priority"`
	ConvoyCount   int       `json:"convoy_count"`
	LastMovement  time.Time `json:"last_movement,omitempty"`
	StalenessHrs  float64   `json:"staleness_hours"`
	StalenessIcon string    `json:"staleness_icon"`
	Score         float64   `json:"score"` // priority × staleness for sorting
}

func showGoal(goalID string) error {
	// Get goal details via bd show
	showCmd := exec.Command("bd", "show", goalID, "--json")
	var stdout bytes.Buffer
	showCmd.Stdout = &stdout

	if err := showCmd.Run(); err != nil {
		return fmt.Errorf("goal '%s' not found", goalID)
	}

	var goals []struct {
		ID          string `json:"id"`
		Title       string `json:"title"`
		Description string `json:"description"`
		Status      string `json:"status"`
		Priority    int    `json:"priority"`
		IssueType   string `json:"issue_type"`
		CreatedAt   string `json:"created_at"`
		UpdatedAt   string `json:"updated_at"`
	}
	if err := json.Unmarshal(stdout.Bytes(), &goals); err != nil {
		return fmt.Errorf("parsing goal data: %w", err)
	}

	if len(goals) == 0 {
		return fmt.Errorf("goal '%s' not found", goalID)
	}

	goal := goals[0]

	// Verify it's an epic
	if goal.IssueType != "epic" {
		return fmt.Errorf("'%s' is not a goal/epic (type: %s)", goalID, goal.IssueType)
	}

	// Get linked convoys
	convoys := getLinkedConvoys(goalID)

	// Compute staleness
	lastMovement := computeGoalLastMovement(goalID, convoys)
	stalenessHrs := time.Since(lastMovement).Hours()
	icon := stalenessIcon(stalenessHrs)

	if goalsJSON {
		out := goalInfo{
			ID:            goal.ID,
			Title:         goal.Title,
			Status:        goal.Status,
			Priority:      goal.Priority,
			ConvoyCount:   len(convoys),
			LastMovement:  lastMovement,
			StalenessHrs:  stalenessHrs,
			StalenessIcon: icon,
		}
		enc := json.NewEncoder(os.Stdout)
		enc.SetIndent("", "  ")
		return enc.Encode(out)
	}

	// Human-readable output
	fmt.Printf("%s P%d  %s: %s\n\n", icon, goal.Priority, style.Bold.Render(goal.ID), goal.Title)
	fmt.Printf("  Status:       %s\n", goal.Status)
	fmt.Printf("  Priority:     P%d\n", goal.Priority)
	fmt.Printf("  Convoys:      %d\n", len(convoys))
	fmt.Printf("  Last activity: %s\n", formatLastActivity(lastMovement))

	if goal.Description != "" {
		fmt.Printf("\n  %s\n", style.Bold.Render("Description:"))
		// Indent description
		for _, line := range strings.Split(goal.Description, "\n") {
			fmt.Printf("  %s\n", line)
		}
	}

	if len(convoys) > 0 {
		fmt.Printf("\n  %s\n", style.Bold.Render("Linked Convoys:"))
		for _, c := range convoys {
			statusIcon := "○"
			if c.Status == "closed" {
				statusIcon = "✓"
			}
			fmt.Printf("    %s %s: %s\n", statusIcon, c.ID, c.Title)
		}
	}

	return nil
}

func listGoals() error {
	// Build list args - bd has its own routing to find the right beads DB
	listArgs := []string{"list", "--type=epic", "--json"}
	if goalsStatus != "" && goalsStatus != "open" {
		if goalsStatus == "all" {
			listArgs = append(listArgs, "--all")
		} else {
			listArgs = append(listArgs, "--status="+goalsStatus)
		}
	}

	listCmd := exec.Command("bd", listArgs...)
	var stdout bytes.Buffer
	listCmd.Stdout = &stdout

	if err := listCmd.Run(); err != nil {
		return fmt.Errorf("listing goals: %w", err)
	}

	var epics []struct {
		ID        string `json:"id"`
		Title     string `json:"title"`
		Status    string `json:"status"`
		Priority  int    `json:"priority"`
		UpdatedAt string `json:"updated_at"`
	}
	if err := json.Unmarshal(stdout.Bytes(), &epics); err != nil {
		return fmt.Errorf("parsing goals list: %w", err)
	}

	// Filter out wisp molecules by default (transient/operational, not strategic goals)
	// These have IDs like "gt-wisp-*" and are molecule-tracking beads, not human goals
	if !goalsIncludeWisp {
		filtered := make([]struct {
			ID        string `json:"id"`
			Title     string `json:"title"`
			Status    string `json:"status"`
			Priority  int    `json:"priority"`
			UpdatedAt string `json:"updated_at"`
		}, 0)
		for _, e := range epics {
			if !isWispEpic(e.ID, e.Title) {
				filtered = append(filtered, e)
			}
		}
		epics = filtered
	}

	// Filter by priority if specified
	if goalsPriority != "" {
		targetPriority := parsePriority(goalsPriority)
		filtered := make([]struct {
			ID        string `json:"id"`
			Title     string `json:"title"`
			Status    string `json:"status"`
			Priority  int    `json:"priority"`
			UpdatedAt string `json:"updated_at"`
		}, 0)
		for _, e := range epics {
			if e.Priority == targetPriority {
				filtered = append(filtered, e)
			}
		}
		epics = filtered
	}

	// Build goal info with staleness computation
	var goals []goalInfo
	for _, epic := range epics {
		convoys := getLinkedConvoys(epic.ID)
		lastMovement := computeGoalLastMovement(epic.ID, convoys)
		stalenessHrs := time.Since(lastMovement).Hours()
		icon := stalenessIcon(stalenessHrs)

		// Score = priority_value × staleness_hours
		// Lower priority number = higher priority, so invert (4 - priority)
		priorityWeight := float64(4 - epic.Priority)
		if priorityWeight < 1 {
			priorityWeight = 1
		}
		score := priorityWeight * stalenessHrs

		goals = append(goals, goalInfo{
			ID:            epic.ID,
			Title:         epic.Title,
			Status:        epic.Status,
			Priority:      epic.Priority,
			ConvoyCount:   len(convoys),
			LastMovement:  lastMovement,
			StalenessHrs:  stalenessHrs,
			StalenessIcon: icon,
			Score:         score,
		})
	}

	// Sort by score (highest attention needed first)
	sort.Slice(goals, func(i, j int) bool {
		return goals[i].Score > goals[j].Score
	})

	if goalsJSON {
		enc := json.NewEncoder(os.Stdout)
		enc.SetIndent("", "  ")
		return enc.Encode(goals)
	}

	if len(goals) == 0 {
		fmt.Println("No goals found.")
		fmt.Println("Create a goal with: bd create --type=epic --title=\"Goal name\"")
		return nil
	}

	// Count active (non-closed) goals
	activeCount := 0
	for _, g := range goals {
		if g.Status != "closed" {
			activeCount++
		}
	}

	fmt.Printf("%s\n\n", style.Bold.Render(fmt.Sprintf("Goals (%d active, sorted by staleness × priority)", activeCount)))

	for _, g := range goals {
		// Format: 🔴 P1  sc-xyz: Title
		//              3 convoys | stale 6h
		priorityStr := fmt.Sprintf("P%d", g.Priority)

		fmt.Printf("  %s %s  %s: %s\n", g.StalenessIcon, priorityStr, g.ID, g.Title)

		// Second line with convoy count and staleness
		activityStr := formatActivityShort(g.StalenessHrs)
		fmt.Printf("         %d convoy(s) | %s\n\n", g.ConvoyCount, activityStr)
	}

	return nil
}

// convoyInfo holds basic convoy info.
type convoyInfo struct {
	ID     string
	Title  string
	Status string
}

// getLinkedConvoys finds convoys linked to a goal (via parent-child relation).
func getLinkedConvoys(goalID string) []convoyInfo {
	var convoys []convoyInfo

	// Query dependencies where this goal is the parent
	// The child issues (convoys) will have depends_on_id = goalID with type = 'parent-child'
	depArgs := []string{"dep", "list", goalID, "--json"}
	depCmd := exec.Command("bd", depArgs...)
	var stdout bytes.Buffer
	depCmd.Stdout = &stdout

	if err := depCmd.Run(); err != nil {
		return convoys
	}

	var deps struct {
		Children []struct {
			ID   string `json:"id"`
			Type string `json:"type"`
		} `json:"children"`
	}
	if err := json.Unmarshal(stdout.Bytes(), &deps); err != nil {
		return convoys
	}

	// Get details for each child that is a convoy
	for _, child := range deps.Children {
		details := getIssueDetails(child.ID)
		if details != nil && details.IssueType == "convoy" {
			convoys = append(convoys, convoyInfo{
				ID:     details.ID,
				Title:  details.Title,
				Status: details.Status,
			})
		}
	}

	return convoys
}

// computeGoalLastMovement computes when the goal last had activity.
// It looks at:
// 1. The goal's own updated_at
// 2. The last activity of any linked convoy's tracked issues
func computeGoalLastMovement(goalID string, convoys []convoyInfo) time.Time {
	// Start with the goal's own updated_at
	showCmd := exec.Command("bd", "show", goalID, "--json")
	var stdout bytes.Buffer
	showCmd.Stdout = &stdout
	showCmd.Run()

	var goals []struct {
		UpdatedAt string `json:"updated_at"`
	}
	json.Unmarshal(stdout.Bytes(), &goals)

	lastMovement := time.Now().Add(-24 * time.Hour) // Default to 24 hours ago
	if len(goals) > 0 && goals[0].UpdatedAt != "" {
		if t, err := time.Parse(time.RFC3339, goals[0].UpdatedAt); err == nil {
			lastMovement = t
		}
	}

	// Check convoy activity
	townBeads, err := getTownBeadsDir()
	if err != nil {
		return lastMovement
	}

	for _, convoy := range convoys {
		tracked := getTrackedIssues(townBeads, convoy.ID)
		for _, t := range tracked {
			// Get issue's updated_at
			details := getIssueDetails(t.ID)
			if details == nil {
				continue
			}
			showCmd := exec.Command("bd", "show", t.ID, "--json")
			var out bytes.Buffer
			showCmd.Stdout = &out
			showCmd.Run()

			var issues []struct {
				UpdatedAt string `json:"updated_at"`
			}
			json.Unmarshal(out.Bytes(), &issues)
			if len(issues) > 0 && issues[0].UpdatedAt != "" {
				if t, err := time.Parse(time.RFC3339, issues[0].UpdatedAt); err == nil {
					if t.After(lastMovement) {
						lastMovement = t
					}
				}
			}
		}
	}

	return lastMovement
}

// stalenessIcon returns the appropriate staleness indicator.
// 🟢 active: moved in last hour
// 🟡 stale: no movement for 1+ hours
// 🔴 stuck: no movement for 4+ hours
func stalenessIcon(hours float64) string {
	if hours < 1 {
		return "🟢"
	}
	if hours < 4 {
		return "🟡"
	}
	return "🔴"
}

// formatLastActivity formats the last activity time for display.
func formatLastActivity(t time.Time) string {
	if t.IsZero() {
		return "unknown"
	}
	d := time.Since(t)
	if d < time.Minute {
		return "just now"
	}
	if d < time.Hour {
		return fmt.Sprintf("%d minutes ago", int(d.Minutes()))
	}
	if d < 24*time.Hour {
		return fmt.Sprintf("%d hours ago", int(d.Hours()))
	}
	return fmt.Sprintf("%d days ago", int(d.Hours()/24))
}

// formatActivityShort returns a short activity string for the list view.
func formatActivityShort(hours float64) string {
	if hours < 1 {
		mins := int(hours * 60)
		if mins < 1 {
			return "active just now"
		}
		return fmt.Sprintf("active %dm ago", mins)
	}
	if hours < 4 {
		return fmt.Sprintf("stale %.0fh", hours)
	}
	return fmt.Sprintf("stuck %.0fh", hours)
}

// parsePriority converts a priority string (P0, P1, etc.) to an int.
func parsePriority(s string) int {
	s = strings.TrimPrefix(strings.ToUpper(s), "P")
	if p, err := strconv.Atoi(s); err == nil {
		return p
	}
	return 2 // Default to P2
}

// isWispEpic returns true if the epic is a transient wisp molecule.
// These are operational/infrastructure beads, not strategic goals that need human attention.
// Detection criteria:
// - ID contains "-wisp-" (molecule tracking beads)
// - Title starts with "mol-" (molecule beads)
func isWispEpic(id, title string) bool {
	// Check for wisp ID pattern (e.g., "gt-wisp-abc123")
	if strings.Contains(id, "-wisp-") {
		return true
	}
	// Check for molecule title pattern
	if strings.HasPrefix(title, "mol-") {
		return true
	}
	return false
}