package middleware

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

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"

	"github.com/yuxingu/digital-psychology/apps/api/pkg/response"
)

const AdminIDKey ctxKey = "admin_id"
const AdminTokenHeader = "Authorization"

// AdminSessionResolver looks up a valid admin session by token.
type AdminSessionResolver interface {
	ResolveAdminID(ctx context.Context, token string) (uuid.UUID, error)
}

// AdminAuth requires Bearer token for /admin routes.
func AdminAuth(resolver AdminSessionResolver) gin.HandlerFunc {
	return func(c *gin.Context) {
		token := BearerToken(c.GetHeader(AdminTokenHeader))
		if token == "" {
			response.Fail(c, http.StatusUnauthorized, 40101, "admin auth required")
			c.Abort()
			return
		}
		adminID, err := resolver.ResolveAdminID(c.Request.Context(), token)
		if err != nil || adminID == uuid.Nil {
			response.Fail(c, http.StatusUnauthorized, 40102, "admin session invalid")
			c.Abort()
			return
		}
		c.Set(string(AdminIDKey), adminID.String())
		c.Next()
	}
}

// AdminIDFromContext returns the authenticated admin id.
func AdminIDFromContext(c *gin.Context) (uuid.UUID, bool) {
	v, ok := c.Get(string(AdminIDKey))
	if !ok {
		return uuid.Nil, false
	}
	id, err := uuid.Parse(v.(string))
	return id, err == nil
}

// BearerToken extracts an opaque token from Authorization (Bearer / bearer).
func BearerToken(h string) string {
	h = strings.TrimSpace(h)
	if h == "" {
		return ""
	}
	lower := strings.ToLower(h)
	if strings.HasPrefix(lower, "bearer ") {
		return strings.TrimSpace(h[len("bearer "):])
	}
	return h
}