package middleware

import (
	"context"
	"net/http"
	"strings"
	"time"

	"music-server/internal/db/repository"
	"music-server/internal/logging"

	"github.com/labstack/echo/v5"
	"go.uber.org/zap"
)

// BearerToken extracts the token from an "Authorization: Bearer <token>" header.
func BearerToken(c *echo.Context) (string, bool) {
	token, ok := strings.CutPrefix(c.Request().Header.Get("Authorization"), "Bearer ")
	return token, ok && token != "" && !strings.Contains(token, " ")
}

// TokenAuth validates session tokens. When disabled is true all requests are let through.
func TokenAuth(q repository.Querier, disabled bool) echo.MiddlewareFunc {
	return func(next echo.HandlerFunc) echo.HandlerFunc {
		return func(c *echo.Context) error {
			if disabled {
				return next(c)
			}

			if c.Request().Header.Get("Authorization") == "" {
				return c.JSON(http.StatusUnauthorized, map[string]string{"error": "Authorization header required"})
			}
			token, ok := BearerToken(c)
			if !ok {
				return c.JSON(http.StatusUnauthorized, map[string]string{"error": "Invalid authorization format. Use: Bearer <token>"})
			}

			ctx := c.Request().Context()
			session, err := q.GetSession(ctx, token)
			if err != nil {
				logging.GetLogger().Warn("Invalid token attempt",
					zap.String("ip", c.RealIP()),
					zap.String("error", err.Error()),
				)
				return c.JSON(http.StatusUnauthorized, map[string]string{"error": "Invalid or expired token"})
			}

			if time.Now().After(session.ExpiresAt.Time) {
				// Clean up in the background with a context that outlives the request.
				go func(ctx context.Context) {
					if err := q.DeleteSession(ctx, token); err != nil {
						logging.GetLogger().Error("Failed to delete expired session", zap.Error(err))
					}
				}(context.WithoutCancel(ctx))
				return c.JSON(http.StatusUnauthorized, map[string]string{"error": "Token expired"})
			}

			c.Set("session", session)
			return next(c)
		}
	}
}