// SPDX-License-Identifier: Apache-2.0
//
// Copyright The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

//go:build windows && (amd64 || arm64)

// Package wuapi provides the Windows Update COM interfaces needed for update searches and metadata.
package wuapi

import (
	"iter"

	"github.com/prometheus-community/windows_exporter/internal/ole"
	"golang.org/x/sys/windows"
)

// Native method slots from wuapi.h, including inherited IDispatch methods.
// https://learn.microsoft.com/en-us/windows/win32/api/wuapi/
const (
	updateSessionPutApplicationID = 8
	updateSessionCreateSearcher   = 12
	updateSessionPutLocale        = 16 // IUpdateSession2
	updateSearcherSearch          = 19
	updateSearcherPutOnline       = 21
	updateSearcherHistoryCount    = 22
	searchResultUpdates           = 9
	updateCollectionItem          = 7
	updateCollectionCount         = 10
	updateTitle                   = 7
	updateCategories              = 11
	updateIdentity                = 19
	updateDeploymentTime          = 30
	updateSeverity                = 34
	identityRevision              = 7
	identityUpdateID              = 8
	categoryCollectionItem        = 7
	categoryCollectionCount       = 9
	categoryName                  = 7
	categoryOrder                 = 12
)

type (
	UpdateSession  struct{ ole.Object } // IUpdateSession2
	UpdateSearcher struct{ ole.Object }
	SearchResult   struct{ ole.Object }
	Update         struct{ ole.Object }
	UpdateIdentity struct{ ole.Object }
	Category       struct{ ole.Object }
)

func NewUpdateSession() (*UpdateSession, error) {
	return ole.Create[UpdateSession](
		windows.GUID{Data1: 0x4cb43d7f, Data2: 0x7eee, Data3: 0x4906, Data4: [8]byte{0x86, 0x98, 0x60, 0xda, 0x1c, 0x38, 0xf2, 0xfe}},
		windows.GUID{Data1: 0x91caf7b0, Data2: 0xeb23, Data3: 0x49ed, Data4: [8]byte{0x99, 0x37, 0xc5, 0x2d, 0x81, 0x7f, 0x46, 0xf7}},
	)
}

func (s *UpdateSession) SetUserLocale(locale uint32) error {
	return s.Put(updateSessionPutLocale, uintptr(locale))
}

func (s *UpdateSession) SetClientApplicationID(id string) error {
	return s.PutString(updateSessionPutApplicationID, id)
}

func (s *UpdateSession) CreateUpdateSearcher() (*UpdateSearcher, error) {
	return s.GetObject[UpdateSearcher](updateSessionCreateSearcher)
}

func (s *UpdateSearcher) SetOnline(online bool) error {
	var value uintptr
	// VARIANT_TRUE is a signed 16-bit -1.
	if online {
		value = 0xffff
	}

	return s.Put(updateSearcherPutOnline, value)
}

func (s *UpdateSearcher) GetTotalHistoryCount() (int32, error) {
	return s.Get[int32](updateSearcherHistoryCount)
}

func (s *UpdateSearcher) Search(criteria string) (*SearchResult, error) {
	return s.GetObjectStringArg[SearchResult](updateSearcherSearch, criteria)
}

func (s *SearchResult) Updates() (*UpdateCollection, error) {
	return s.GetObject[UpdateCollection](searchResultUpdates)
}

func (u *Update) Title() (string, error)        { return u.String(updateTitle) }
func (u *Update) MsrcSeverity() (string, error) { return u.String(updateSeverity) }
func (u *Update) Categories() (*CategoryCollection, error) {
	return u.GetObject[CategoryCollection](updateCategories)
}

func (u *Update) Identity() (*UpdateIdentity, error) {
	return u.GetObject[UpdateIdentity](updateIdentity)
}

func (u *Update) LastDeploymentChangeTime() (ole.DATE, error) {
	return u.Get[ole.DATE](updateDeploymentTime)
}
func (i *UpdateIdentity) UpdateID() (string, error)      { return i.String(identityUpdateID) }
func (i *UpdateIdentity) RevisionNumber() (int32, error) { return i.Get[int32](identityRevision) }
func (c *Category) Name() (string, error)                { return c.String(categoryName) }
func (c *Category) Order() (int32, error)                { return c.Get[int32](categoryOrder) }

// UpdateCollection uses IUpdateCollection's native layout and zero-based indices.
type UpdateCollection struct{ ole.Object }

func (c *UpdateCollection) count() (int32, error) {
	return c.Get[int32](updateCollectionCount)
}

func (c *UpdateCollection) item(index int32) (*Update, error) {
	return c.GetObjectArg[Update](updateCollectionItem, uintptr(index))
}

// All yields borrowed updates, valid only in the loop body. Callers must not
// release or retain them. Item errors can be skipped by continuing the loop.
// The collection itself remains owned by the caller and must be released.
func (c *UpdateCollection) All() iter.Seq2[*Update, error] {
	return ole.BorrowedItems(c.count, c.item, func(item *Update) { item.Release() })
}

// CategoryCollection uses ICategoryCollection's distinct native count slot.
type CategoryCollection struct{ ole.Object }

func (c *CategoryCollection) count() (int32, error) {
	return c.Get[int32](categoryCollectionCount)
}

func (c *CategoryCollection) item(index int32) (*Category, error) {
	return c.GetObjectArg[Category](categoryCollectionItem, uintptr(index))
}

// All yields borrowed categories, valid only in the loop body. Callers must not
// release or retain them. Item errors can be skipped by continuing the loop.
// The collection itself remains owned by the caller and must be released.
func (c *CategoryCollection) All() iter.Seq2[*Category, error] {
	return ole.BorrowedItems(c.count, c.item, func(item *Category) { item.Release() })
}