package web

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/steveyegge/gastown/internal/activity"
	"github.com/steveyegge/gastown/internal/workspace"
)

// LiveConvoyFetcher fetches convoy data from beads.
type LiveConvoyFetcher struct {
	townBeads string
}

// NewLiveConvoyFetcher creates a fetcher for the current workspace.
func NewLiveConvoyFetcher() (*LiveConvoyFetcher, error) {
	townRoot, err := workspace.FindFromCwdOrError()
	if err != nil {
		return nil, fmt.Errorf("not in a Gas Town workspace: %w", err)
	}

	return &LiveConvoyFetcher{
		townBeads: filepath.Join(townRoot, ".beads"),
	}, nil
}

// FetchConvoys fetches all open convoys with their activity data.
func (f *LiveConvoyFetcher) FetchConvoys() ([]ConvoyRow, error) {
	// List all open convoy-type issues
	listArgs := []string{"list", "--type=convoy", "--status=open", "--json"}
	listCmd := exec.Command("bd", listArgs...)
	listCmd.Dir = f.townBeads

	var stdout bytes.Buffer
	listCmd.Stdout = &stdout

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

	var convoys []struct {
		ID        string `json:"id"`
		Title     string `json:"title"`
		Status    string `json:"status"`
		CreatedAt string `json:"created_at"`
	}
	if err := json.Unmarshal(stdout.Bytes(), &convoys); err != nil {
		return nil, fmt.Errorf("parsing convoy list: %w", err)
	}

	// Build convoy rows with activity data
	rows := make([]ConvoyRow, 0, len(convoys))
	for _, c := range convoys {
		row := ConvoyRow{
			ID:     c.ID,
			Title:  c.Title,
			Status: c.Status,
		}

		// Get tracked issues for progress and activity calculation
		tracked := f.getTrackedIssues(c.ID)
		row.Total = len(tracked)

		var mostRecentActivity time.Time
		for _, t := range tracked {
			if t.Status == "closed" {
				row.Completed++
			}
			// Track most recent activity from workers
			if t.LastActivity.After(mostRecentActivity) {
				mostRecentActivity = t.LastActivity
			}
		}

		row.Progress = fmt.Sprintf("%d/%d", row.Completed, row.Total)

		// Calculate activity info from most recent worker activity
		if !mostRecentActivity.IsZero() {
			row.LastActivity = activity.Calculate(mostRecentActivity)
		} else {
			row.LastActivity = activity.Info{
				FormattedAge: "no activity",
				ColorClass:   activity.ColorUnknown,
			}
		}

		// Get tracked issues for expandable view
		row.TrackedIssues = make([]TrackedIssue, len(tracked))
		for i, t := range tracked {
			row.TrackedIssues[i] = TrackedIssue{
				ID:       t.ID,
				Title:    t.Title,
				Status:   t.Status,
				Assignee: t.Assignee,
			}
		}

		rows = append(rows, row)
	}

	return rows, nil
}

// trackedIssueInfo holds info about an issue being tracked by a convoy.
type trackedIssueInfo struct {
	ID           string
	Title        string
	Status       string
	Assignee     string
	LastActivity time.Time
}

// getTrackedIssues fetches tracked issues for a convoy.
func (f *LiveConvoyFetcher) getTrackedIssues(convoyID string) []trackedIssueInfo {
	dbPath := filepath.Join(f.townBeads, "beads.db")

	// Query tracked dependencies from SQLite
	safeConvoyID := strings.ReplaceAll(convoyID, "'", "''")
	queryCmd := exec.Command("sqlite3", "-json", dbPath,
		fmt.Sprintf(`SELECT depends_on_id, type FROM dependencies WHERE issue_id = '%s' AND type = 'tracks'`, safeConvoyID))

	var stdout bytes.Buffer
	queryCmd.Stdout = &stdout
	if err := queryCmd.Run(); err != nil {
		return nil
	}

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

	// Collect issue IDs (normalize external refs)
	issueIDs := make([]string, 0, len(deps))
	for _, dep := range deps {
		issueID := dep.DependsOnID
		if strings.HasPrefix(issueID, "external:") {
			parts := strings.SplitN(issueID, ":", 3)
			if len(parts) == 3 {
				issueID = parts[2]
			}
		}
		issueIDs = append(issueIDs, issueID)
	}

	// Batch fetch issue details
	details := f.getIssueDetailsBatch(issueIDs)

	// Get worker activity from tmux sessions based on assignees
	workers := f.getWorkersFromAssignees(details)

	// Build result
	result := make([]trackedIssueInfo, 0, len(issueIDs))
	for _, id := range issueIDs {
		info := trackedIssueInfo{ID: id}

		if d, ok := details[id]; ok {
			info.Title = d.Title
			info.Status = d.Status
			info.Assignee = d.Assignee
		} else {
			info.Title = "(external)"
			info.Status = "unknown"
		}

		if w, ok := workers[id]; ok && w.LastActivity != nil {
			info.LastActivity = *w.LastActivity
		}

		result = append(result, info)
	}

	return result
}

// issueDetail holds basic issue info.
type issueDetail struct {
	ID       string
	Title    string
	Status   string
	Assignee string
}

// getIssueDetailsBatch fetches details for multiple issues.
func (f *LiveConvoyFetcher) getIssueDetailsBatch(issueIDs []string) map[string]*issueDetail {
	result := make(map[string]*issueDetail)
	if len(issueIDs) == 0 {
		return result
	}

	args := append([]string{"show"}, issueIDs...)
	args = append(args, "--json")

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

	if err := showCmd.Run(); err != nil {
		return result
	}

	var issues []struct {
		ID       string `json:"id"`
		Title    string `json:"title"`
		Status   string `json:"status"`
		Assignee string `json:"assignee"`
	}
	if err := json.Unmarshal(stdout.Bytes(), &issues); err != nil {
		return result
	}

	for _, issue := range issues {
		result[issue.ID] = &issueDetail{
			ID:       issue.ID,
			Title:    issue.Title,
			Status:   issue.Status,
			Assignee: issue.Assignee,
		}
	}

	return result
}

// workerDetail holds worker info including last activity.
type workerDetail struct {
	Worker       string
	LastActivity *time.Time
}

// getWorkersFromAssignees gets worker activity from tmux sessions based on issue assignees.
// Assignees are in format "rigname/polecats/polecatname" which maps to tmux session "gt-rigname-polecatname".
func (f *LiveConvoyFetcher) getWorkersFromAssignees(details map[string]*issueDetail) map[string]*workerDetail {
	result := make(map[string]*workerDetail)

	// Collect unique assignees and map them to issue IDs
	assigneeToIssues := make(map[string][]string)
	for issueID, detail := range details {
		if detail == nil || detail.Assignee == "" {
			continue
		}
		assigneeToIssues[detail.Assignee] = append(assigneeToIssues[detail.Assignee], issueID)
	}

	if len(assigneeToIssues) == 0 {
		return result
	}

	// For each unique assignee, look up tmux session activity
	for assignee, issueIDs := range assigneeToIssues {
		activity := f.getSessionActivityForAssignee(assignee)
		if activity == nil {
			continue
		}

		// Apply this activity to all issues assigned to this worker
		for _, issueID := range issueIDs {
			result[issueID] = &workerDetail{
				Worker:       assignee,
				LastActivity: activity,
			}
		}
	}

	return result
}

// getSessionActivityForAssignee looks up tmux session activity for an assignee.
// Assignee format: "rigname/polecats/polecatname" -> session "gt-rigname-polecatname"
func (f *LiveConvoyFetcher) getSessionActivityForAssignee(assignee string) *time.Time {
	// Parse assignee: "roxas/polecats/dag" -> rig="roxas", polecat="dag"
	parts := strings.Split(assignee, "/")
	if len(parts) != 3 || parts[1] != "polecats" {
		return nil
	}
	rig := parts[0]
	polecat := parts[2]

	// Construct session name
	sessionName := fmt.Sprintf("gt-%s-%s", rig, polecat)

	// Query tmux for session activity
	// Format: session_activity returns unix timestamp
	cmd := exec.Command("tmux", "list-sessions", "-F", "#{session_name}|#{session_activity}",
		"-f", fmt.Sprintf("#{==:#{session_name},%s}", sessionName))
	var stdout bytes.Buffer
	cmd.Stdout = &stdout
	if err := cmd.Run(); err != nil {
		return nil
	}

	output := strings.TrimSpace(stdout.String())
	if output == "" {
		return nil
	}

	// Parse output: "gt-roxas-dag|1704312345"
	outputParts := strings.Split(output, "|")
	if len(outputParts) < 2 {
		return nil
	}

	var activityUnix int64
	if _, err := fmt.Sscanf(outputParts[1], "%d", &activityUnix); err != nil || activityUnix == 0 {
		return nil
	}

	activity := time.Unix(activityUnix, 0)
	return &activity
}