package middleware

import (
	"net/http"
	"strings"

	"bugulma/backend/internal/service"

	"github.com/gin-gonic/gin"
)

// MaintenanceMiddleware blocks requests when maintenance mode is enabled.
// Whitelisted path prefixes are allowed through (e.g., /api/v1/admin, /health).
func MaintenanceMiddleware(settingsSvc *service.SettingsService, whitelistPrefixes []string) gin.HandlerFunc {
	return func(c *gin.Context) {
		// Get current maintenance setting
		m, err := settingsSvc.GetMaintenanceCached(c.Request.Context())
		if err != nil {
			// On error, be conservative and allow request (avoid taking down the site due to a read error)
			c.Next()
			return
		}

		// Always set headers so clients can show a banner if desired
		if m.Enabled {
			c.Header("X-Maintenance", "true")
			c.Header("X-Maintenance-Message", m.Message)
		} else {
			c.Header("X-Maintenance", "false")
			c.Header("X-Maintenance-Message", "")
		}

		// If not enabled, nothing to do
		if !m.Enabled {
			c.Next()
			return
		}

		// If path is whitelisted, allow through
		path := c.Request.URL.Path
		for _, p := range whitelistPrefixes {
			if strings.HasPrefix(path, p) {
				c.Next()
				return
			}
		}

		// Allow if client's IP is in allowed list
		clientIP := c.ClientIP()
		xReal := c.GetHeader("X-Real-IP")
		xForwarded := c.GetHeader("X-Forwarded-For")
		for _, a := range m.AllowedIPs {
			if a == clientIP || a == xReal || (xForwarded != "" && strings.HasPrefix(xForwarded, a)) {
				c.Next()
				return
			}
		}

		// Block the request with 503
		c.AbortWithStatusJSON(http.StatusServiceUnavailable, gin.H{"message": m.Message, "maintenance": true})
	}
}