package middleware

import (
	"bytes"
	"encoding/json"
	"io"

	"github.com/Tencent/WeKnora/internal/accesspolicy"
	apperrors "github.com/Tencent/WeKnora/internal/errors"
	"github.com/Tencent/WeKnora/internal/types"
	"github.com/gin-gonic/gin"
)

// RequireKnowledgeVersionTransfer prevents stripping no-export provenance by
// copying or moving protected material into an unrelated, exportable KB.
func RequireKnowledgeVersionTransfer() gin.HandlerFunc {
	return func(c *gin.Context) {
		ctx := c.Request.Context()
		if types.IsSystemAdminFromContext(ctx) || types.TenantRoleFromContext(ctx).HasPermission(types.TenantRoleAdmin) {
			c.Next()
			return
		}
		if _, apiKey := types.TenantAPIKeyScopeFromContext(ctx); apiKey {
			c.Next()
			return
		}
		snapshot := accesspolicy.FromContext(ctx)
		if snapshot == nil {
			c.Next()
			return
		}
		body, err := io.ReadAll(io.LimitReader(c.Request.Body, (1<<20)+1))
		if err != nil || len(body) > 1<<20 {
			_ = c.Error(apperrors.NewBadRequestError("复制或移动请求过大"))
			c.Abort()
			return
		}
		c.Request.Body = io.NopCloser(bytes.NewReader(body))
		var request struct {
			SourceID   string `json:"source_id"`
			SourceKBID string `json:"source_kb_id"`
		}
		if err = json.Unmarshal(body, &request); err != nil {
			_ = c.Error(apperrors.NewBadRequestError("无效的复制或移动请求"))
			c.Abort()
			return
		}
		for _, id := range []string{request.SourceID, request.SourceKBID} {
			if id != "" && (snapshot.NoExport["knowledge:"+id] || snapshot.Publications["knowledge:"+id]) {
				_ = c.Error(apperrors.NewForbiddenError("此知识库不可复制或移动到其他知识库；请在我的资源版本中创建独立个人版本"))
				c.Abort()
				return
			}
		}
		c.Next()
	}
}