package db

import (
	"context"
	"fmt"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

type DB struct {
	pool *pgxpool.Pool
}

func New(databaseURL string) (*DB, error) {
	config, err := pgxpool.ParseConfig(databaseURL)
	if err != nil {
		return nil, fmt.Errorf("parse database config: %w", err)
	}

	pool, err := pgxpool.NewWithConfig(context.Background(), config)
	if err != nil {
		return nil, fmt.Errorf("create pool: %w", err)
	}

	if err := pool.Ping(context.Background()); err != nil {
		return nil, fmt.Errorf("ping database: %w", err)
	}

	return &DB{pool: pool}, nil
}

func (db *DB) Close() {
	db.pool.Close()
}

func (db *DB) Pool() *pgxpool.Pool {
	return db.pool
}

func (db *DB) QueryRow(ctx context.Context, sql string, args ...interface{}) pgx.Row {
	return db.pool.QueryRow(ctx, sql, args...)
}

func (db *DB) Query(ctx context.Context, sql string, args ...interface{}) (pgx.Rows, error) {
	return db.pool.Query(ctx, sql, args...)
}

func (db *DB) Exec(ctx context.Context, sql string, args ...interface{}) error {
	_, err := db.pool.Exec(ctx, sql, args...)
	return err
}

// Stats contains database statistics for the admin dashboard
type Stats struct {
	TotalUsers        int64 `json:"totalUsers"`
	UsersToday        int64 `json:"usersToday"`
	UsersThisWeek     int64 `json:"usersThisWeek"`
	UsersThisMonth    int64 `json:"usersThisMonth"`
	ActiveUsers7Days  int64 `json:"activeUsers7Days"`
	ActiveUsers30Days int64 `json:"activeUsers30Days"`
	MagicLinksSent    int64 `json:"magicLinksSent"`
	MagicLinksUsed    int64 `json:"magicLinksUsed"`
	MagicLinksPending int64 `json:"magicLinksPending"`
	OAuthUsers        int64 `json:"oauthUsers"`
	PasswordUsers     int64 `json:"passwordUsers"`
}

// GetStats returns database statistics for the admin dashboard
func (db *DB) GetStats(ctx context.Context) (*Stats, error) {
	stats := &Stats{}

	// Total users
	err := db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users`).Scan(&stats.TotalUsers)
	if err != nil {
		return nil, err
	}

	// Users created today
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE created_at >= CURRENT_DATE`).Scan(&stats.UsersToday)
	if err != nil {
		return nil, err
	}

	// Users created this week
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE created_at >= CURRENT_DATE - INTERVAL '7 days'`).Scan(&stats.UsersThisWeek)
	if err != nil {
		return nil, err
	}

	// Users created this month
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE created_at >= CURRENT_DATE - INTERVAL '30 days'`).Scan(&stats.UsersThisMonth)
	if err != nil {
		return nil, err
	}

	// Active users (logged in) in last 7 days
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE last_login_at >= CURRENT_DATE - INTERVAL '7 days'`).Scan(&stats.ActiveUsers7Days)
	if err != nil {
		return nil, err
	}

	// Active users in last 30 days
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE last_login_at >= CURRENT_DATE - INTERVAL '30 days'`).Scan(&stats.ActiveUsers30Days)
	if err != nil {
		return nil, err
	}

	// Magic links sent (total)
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM magic_links`).Scan(&stats.MagicLinksSent)
	if err != nil {
		return nil, err
	}

	// Magic links used
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM magic_links WHERE used = TRUE`).Scan(&stats.MagicLinksUsed)
	if err != nil {
		return nil, err
	}

	// Pending magic links
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM magic_links WHERE used = FALSE AND expires_at > NOW()`).Scan(&stats.MagicLinksPending)
	if err != nil {
		return nil, err
	}

	// OAuth users
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE provider != 'email'`).Scan(&stats.OAuthUsers)
	if err != nil {
		return nil, err
	}

	// Password users
	err = db.pool.QueryRow(ctx, `SELECT COUNT(*) FROM users WHERE password_hash IS NOT NULL`).Scan(&stats.PasswordUsers)
	if err != nil {
		return nil, err
	}

	return stats, nil
}