package db

import (
	"context"
	"fmt"
	"strings"
	"time"
)

func (s *Store) DashboardOverview(limit int) (map[string]any, error) {
	if limit <= 0 || limit > 200 {
		limit = 80
	}
	feedbackTotal, _ := s.countTable("feedback_tickets")
	feedbackToday, _ := s.countWhere("feedback_tickets", "created_at LIKE ?", time.Now().UTC().Format("2006-01-02")+"%")
	sourceTotal, _ := s.countTable("source_endpoints")
	sourceVisible, _ := s.countWhere("source_endpoints", "enabled = 1 AND client_visible = 1")
	releaseTotal, _ := s.countTable("release_notices")
	mailFailed, _ := s.countWhere("mail_records", "status = ?", "failed")
	statusCounts, _ := s.groupCounts("feedback_tickets", "status")
	healthCounts, _ := s.groupCounts("source_endpoints", "last_status")
	recentChecks, _ := s.RecentSourceChecks(limit)
	recentCalls, _ := s.RecentSourceCalls(limit)
	averageLatency, _ := s.AverageSourceLatencyBuckets(limit)
	audit, _ := s.ListAuditLogs(10)
	return map[string]any{
		"ok": true,
		"kpis": map[string]any{
			"feedbackTotal":  feedbackTotal,
			"feedbackToday":  feedbackToday,
			"sourceTotal":    sourceTotal,
			"sourceVisible":  sourceVisible,
			"releaseNotices": releaseTotal,
			"mailFailed":     mailFailed,
		},
		"feedbackStatus": statusCounts,
		"sourceHealth":   healthCounts,
		"heartbeats":     recentChecks,
		"averageLatency": averageLatency,
		"clientCalls":    recentCalls,
		"database":       s.Status(),
		"audit":          audit,
	}, nil
}

func (s *Store) AverageSourceLatencyBuckets(limit int) ([]map[string]any, error) {
	if limit <= 0 || limit > 200 {
		limit = 80
	}
	rows, err := s.query(`SELECT checked_at, latency_ms, status FROM endpoint_health_checks ORDER BY checked_at DESC, id DESC LIMIT ?`, limit*4)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	type bucket struct {
		label  string
		total  int
		count  int
		ok     int
		latest string
	}
	order := []string{}
	buckets := map[string]*bucket{}
	for rows.Next() {
		var checkedAt, status string
		var latency int
		if err := rows.Scan(&checkedAt, &latency, &status); err != nil {
			return nil, err
		}
		label := latencyBucketLabel(checkedAt)
		if label == "" {
			label = checkedAt
		}
		item, ok := buckets[label]
		if !ok {
			item = &bucket{label: label, latest: checkedAt}
			buckets[label] = item
			order = append(order, label)
		}
		item.total += latency
		item.count++
		if status == "ok" || status == "redirected" {
			item.ok++
		}
		if checkedAt > item.latest {
			item.latest = checkedAt
		}
	}
	if err := rows.Err(); err != nil {
		return nil, err
	}
	out := []map[string]any{}
	for i := len(order) - 1; i >= 0; i-- {
		item := buckets[order[i]]
		if item == nil || item.count == 0 {
			continue
		}
		out = append(out, map[string]any{
			"label":          item.label,
			"averageLatency": item.total / item.count,
			"avgLatencyMs":   item.total / item.count,
			"sampleCount":    item.count,
			"healthyCount":   item.ok,
			"checkedAt":      item.latest,
		})
	}
	if len(out) > limit {
		out = out[len(out)-limit:]
	}
	return out, nil
}

func latencyBucketLabel(value string) string {
	if value == "" {
		return ""
	}
	parsed, err := time.Parse(time.RFC3339, value)
	if err != nil {
		if len(value) >= 16 {
			return value[:16]
		}
		return value
	}
	return parsed.UTC().Format("01-02 15:04")
}

func (s *Store) RecentSourceChecks(limit int) ([]map[string]any, error) {
	rows, err := s.query(`SELECT h.id, h.source_db_id, COALESCE(e.source_id, ''), COALESCE(e.name, ''), h.status, h.latency_ms, h.error, h.checked_at
		FROM endpoint_health_checks h LEFT JOIN source_endpoints e ON e.id = h.source_db_id
		ORDER BY h.checked_at DESC, h.id DESC LIMIT ?`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	items := []map[string]any{}
	for rows.Next() {
		var id, sourceDBID int64
		var sourceID, name, status, message, checkedAt string
		var latency int
		if err := rows.Scan(&id, &sourceDBID, &sourceID, &name, &status, &latency, &message, &checkedAt); err != nil {
			return nil, err
		}
		if sourceID == "" {
			sourceID = fmt.Sprintf("deleted-%d", sourceDBID)
		}
		if name == "" {
			name = fmt.Sprintf("已删除接口 #%d", sourceDBID)
		}
		items = append(items, map[string]any{"id": id, "sourceDbId": sourceDBID, "sourceId": sourceID, "name": name, "status": status, "latencyMs": latency, "error": message, "checkedAt": checkedAt})
	}
	return items, rows.Err()
}

func (s *Store) RecentSourceCalls(limit int) ([]map[string]any, error) {
	rows, err := s.query(`SELECT id, source_id, status, latency_ms, error, client, created_at FROM endpoint_call_logs ORDER BY created_at DESC, id DESC LIMIT ?`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	items := []map[string]any{}
	for rows.Next() {
		var id int64
		var sourceID, status, message, client, createdAt string
		var latency int
		if err := rows.Scan(&id, &sourceID, &status, &latency, &message, &client, &createdAt); err != nil {
			return nil, err
		}
		items = append(items, map[string]any{"id": id, "sourceId": sourceID, "status": status, "latencyMs": latency, "error": message, "client": client, "createdAt": createdAt})
	}
	return items, rows.Err()
}

func (s *Store) InsertAudit(log AuditLog) error {
	return s.InsertAuditContext(context.Background(), log)
}

func (s *Store) InsertAuditContext(ctx context.Context, log AuditLog) error {
	if log.CreatedAt == "" {
		log.CreatedAt = Now()
	}
	conn, d := s.active()
	if conn == nil {
		return fmt.Errorf("database is not available")
	}
	_, err := conn.ExecContext(ctx, d.rebind(`INSERT INTO audit_logs (actor, type, target, message, ip, user_agent, created_at) VALUES (?, ?, ?, ?, ?, ?, ?)`),
		sanitize(log.Actor), sanitize(log.Type), sanitize(log.Target), sanitize(log.Message), sanitize(log.IP), sanitize(log.UserAgent), log.CreatedAt)
	return err
}

func (s *Store) ListAuditLogs(limit int) ([]AuditLog, error) {
	if limit <= 0 || limit > 200 {
		limit = 100
	}
	rows, err := s.query(`SELECT id, actor, type, target, message, ip, user_agent, created_at FROM audit_logs ORDER BY id DESC LIMIT ?`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanAuditRows(rows)
}

func (s *Store) ListAuditLogsPage(filters AuditFilters) (AuditPage, error) {
	page := filters.Page
	if page <= 0 {
		page = 1
	}
	perPage := filters.PerPage
	if perPage <= 0 {
		perPage = 35
	}
	if perPage > 100 {
		perPage = 100
	}
	where, args := auditWhere(filters)
	var total int
	if err := s.queryRow(`SELECT COUNT(*) FROM audit_logs`+where, args...).Scan(&total); err != nil {
		return AuditPage{}, err
	}
	offset := (page - 1) * perPage
	queryArgs := append(append([]any{}, args...), perPage, offset)
	rows, err := s.query(`SELECT id, actor, type, target, message, ip, user_agent, created_at FROM audit_logs`+where+` ORDER BY id DESC LIMIT ? OFFSET ?`, queryArgs...)
	if err != nil {
		return AuditPage{}, err
	}
	defer rows.Close()
	items, err := scanAuditRows(rows)
	if err != nil {
		return AuditPage{}, err
	}
	return AuditPage{Items: items, Total: total, Page: page, PerPage: perPage}, nil
}

func auditWhere(filters AuditFilters) (string, []any) {
	clauses := []string{}
	args := []any{}
	if value := strings.TrimSpace(filters.Type); value != "" {
		clauses = append(clauses, "type = ?")
		args = append(args, sanitize(value))
	}
	if value := strings.TrimSpace(filters.Target); value != "" {
		clauses = append(clauses, "target = ?")
		args = append(args, sanitize(value))
	}
	if value := strings.TrimSpace(filters.Query); value != "" {
		clauses = append(clauses, "(actor LIKE ? OR type LIKE ? OR target LIKE ? OR message LIKE ? OR ip LIKE ?)")
		like := "%" + sanitize(value) + "%"
		args = append(args, like, like, like, like, like)
	}
	if len(clauses) == 0 {
		return "", args
	}
	return " WHERE " + strings.Join(clauses, " AND "), args
}

func (s *Store) ListAuditLogsForTarget(target string, limit int) ([]AuditLog, error) {
	if limit <= 0 || limit > 200 {
		limit = 100
	}
	rows, err := s.query(`SELECT id, actor, type, target, message, ip, user_agent, created_at FROM audit_logs WHERE target = ? ORDER BY id DESC LIMIT ?`, target, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	return scanAuditRows(rows)
}

func (s *Store) countTable(table string) (int, error) {
	if !validStatsTable(table) {
		return 0, fmt.Errorf("invalid table %q", table)
	}
	var total int
	err := s.queryRow(`SELECT COUNT(*) FROM ` + table).Scan(&total)
	return total, err
}

func (s *Store) countWhere(table, where string, args ...any) (int, error) {
	if !validStatsTable(table) {
		return 0, fmt.Errorf("invalid table %q", table)
	}
	var total int
	err := s.queryRow(`SELECT COUNT(*) FROM `+table+` WHERE `+where, args...).Scan(&total)
	return total, err
}

func (s *Store) groupCounts(table, column string) (map[string]int, error) {
	if !validStatsColumn(table, column) {
		return nil, fmt.Errorf("invalid group %s.%s", table, column)
	}
	rows, err := s.query(`SELECT ` + column + `, COUNT(*) FROM ` + table + ` GROUP BY ` + column)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := map[string]int{}
	for rows.Next() {
		var key string
		var count int
		if err := rows.Scan(&key, &count); err != nil {
			return nil, err
		}
		if key == "" {
			key = "unknown"
		}
		out[key] = count
	}
	return out, rows.Err()
}

func validStatsTable(table string) bool {
	switch table {
	case "feedback_tickets", "source_endpoints", "release_notices", "mail_records":
		return true
	default:
		return false
	}
}

func validStatsColumn(table, column string) bool {
	switch table + "." + column {
	case "feedback_tickets.status", "source_endpoints.last_status":
		return true
	default:
		return false
	}
}