package main

import (
	"fmt"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/mappu/miqt/qt"
	bolt "go.etcd.io/bbolt"
)

type MainWindow struct {
	ui *MainWindowUi

	databaseContext      *qt.QMenu
	bucketContext        *qt.QMenu
	lastContextSelection *qt.QTreeWidgetItem
}

func NewMainWindow() *MainWindow {
	this := &MainWindow{}
	this.ui = NewMainWindowUi()

	this.on_bucketTree_currentItemChanged(nil, nil)

	this.databaseContext = qt.NewQMenu()
	this.databaseContext.QWidget.AddAction(this.ui.actionRefresh_buckets)
	this.databaseContext.QWidget.AddAction(this.ui.actionAdd_bucket)
	this.databaseContext.AddSeparator()
	this.databaseContext.QWidget.AddAction(this.ui.actionDisconnect)

	this.bucketContext = qt.NewQMenu()
	this.bucketContext.QWidget.AddAction(this.ui.actionRefresh_buckets)
	this.bucketContext.QWidget.AddAction(this.ui.actionAdd_bucket)
	this.bucketContext.AddSeparator()
	this.bucketContext.QWidget.AddAction(this.ui.actionDelete_bucket)

	// Connections
	this.ui.actionNew_database.OnTriggered(this.on_actionNew_database_triggered)
	this.ui.actionOpen_database.OnTriggered(this.on_actionOpen_database_triggered)
	this.ui.actionOpen_database_as_read_only.OnTriggered(this.on_actionOpen_database_as_read_only_triggered)
	this.ui.actionExit.OnTriggered(this.on_actionExit_triggered)
	this.ui.actionAbout_Qt.OnTriggered(this.on_actionAbout_Qt_triggered)
	this.ui.actionAbout_qbolt.OnTriggered(this.on_actionAbout_qbolt_triggered)
	this.ui.actionDisconnect.OnTriggered(this.on_actionDisconnect_triggered)
	this.ui.bucketTree.OnCustomContextMenuRequested(this.on_bucketTree_customContextMenuRequested)
	this.ui.actionRefresh_buckets.OnTriggered(this.on_actionRefresh_buckets_triggered)
	this.ui.bucketTree.OnCurrentItemChanged(this.on_bucketTree_currentItemChanged)
	this.ui.actionClear_selection.OnTriggered(this.on_actionClear_selection_triggered)
	this.ui.bucketData.OnDoubleClicked(this.on_bucketData_doubleClicked)
	this.ui.actionAdd_bucket.OnTriggered(this.on_actionAdd_bucket_triggered)
	this.ui.actionDelete_bucket.OnTriggered(this.on_actionDelete_bucket_triggered)
	this.ui.AddDataButton.OnClicked(this.on_AddDataButton_clicked)
	this.ui.DeleteDataButton.OnClicked(this.on_DeleteDataButton_clicked)
	this.ui.bucketData.OnItemSelectionChanged(this.on_bucketData_itemSelectionChanged)

	return this
}

const (
	BdbPointerRole = int(qt.UserRole + 1)
	BinaryDataRole = int(qt.UserRole + 2)
)

var bdbs []*bolt.DB = nil

func SET_BDB(top *qt.QTreeWidgetItem, bdb *bolt.DB) {
	idx := len(bdbs)
	bdbs = append(bdbs, bdb)
	top.SetData(0, BdbPointerRole, qt.NewQVariant7(idx)) // Don't store a Go pointer in Qt memory
}

func GET_BDB(top *qt.QTreeWidgetItem) *bolt.DB {
	if top == nil {
		panic("Passed a nil QTreeWidgetItem")
	}

	dataVariant := top.Data(0, BdbPointerRole)
	if dataVariant == nil {
		panic("Selected item has no bdb")
	}

	return bdbs[dataVariant.ToInt()]
}

func (this *MainWindow) Widget() *qt.QWidget {
	return this.ui.centralWidget
}

func (this *MainWindow) on_actionNew_database_triggered() {
	file := qt.QFileDialog_GetSaveFileName2(this.Widget(), "Save new bolt database as...")
	if len(file) > 0 {
		this.openDatabase(file, false)
	}
}

func (this *MainWindow) on_actionOpen_database_triggered() {
	file := qt.QFileDialog_GetOpenFileName2(this.Widget(), "Select bolt database...")
	if len(file) > 0 {
		this.openDatabase(file, false)
	}
}

func (this *MainWindow) on_actionOpen_database_as_read_only_triggered() {
	file := qt.QFileDialog_GetOpenFileName2(this.Widget(), "Select bolt database...")
	if len(file) > 0 {
		this.openDatabase(file, true)
	}
}

func (this *MainWindow) alert(message string) {
	qt.QMessageBox_Critical(this.Widget(), "qbolt", message)
}

func (this *MainWindow) openDatabase(file string, readOnly bool) {

	// Open
	bdb, err := Bolt_Open(readOnly, file)
	if err != nil {
		this.alert(fmt.Sprintf("Error opening database: %s", err.Error()))
		return
	}

	top := qt.NewQTreeWidgetItem()
	top.SetText(0, filepath.Base(file))
	top.SetIcon(0, qt.NewQIcon4(":/rsrc/database.png"))
	SET_BDB(top, bdb)
	this.ui.bucketTree.AddTopLevelItem(top)

	this.refreshBucketTree(top)
	this.ui.bucketTree.SetCurrentItem(top)

	this.ui.bucketTree.ExpandItem(top)
}

func getDisplayName(qba string) string {
	if qba == "" {
		return "<empty>"
	}

	ret := strconv.Quote(qba)
	return ret[1 : len(ret)-1]
}

func (this *MainWindow) refreshBucketTree(itm *qt.QTreeWidgetItem) {
	ws := this.getSelection(itm)

	// Remove existing children
	i := itm.ChildCount()
	for i > 0 {
		itm.TakeChild(i - 1).Delete()
		i -= 1
	}

	err := Bolt_ListBuckets(ws.bdb, ws.browse, func(qba string) {

		child := qt.NewQTreeWidgetItem6(itm) // NewQTreeWidgetItem()
		child.SetText(0, getDisplayName(qba))
		child.SetData(0, BinaryDataRole, qt.NewQVariant15(MakeQByteArray(qba)))
		child.SetIcon(0, qt.NewQIcon4(":/rsrc/table.png"))

		itm.AddChild(child)
		this.refreshBucketTree(child)
	})
	if err != nil {
		this.alert(fmt.Sprintf("Error listing buckets under %s: %s", strings.Join(ws.browse, `/`), err.Error()))
		return
	}
}

func (this *MainWindow) on_actionExit_triggered() {
	this.ui.MainWindow.Close()
}

func (this *MainWindow) on_actionAbout_Qt_triggered() {
	qt.QApplication_AboutQt()
}

func (this *MainWindow) on_actionAbout_qbolt_triggered() {
	qt.QMessageBox_About(
		this.Widget(),
		qt.QGuiApplication_ApplicationDisplayName(),
		"<b>QBolt "+Version+"</b><br>Graphical interface for managing Bolt databases<br><br>"+
			"- <a href='https://github.com/boltdb/bolt'>About BoltDB</a><br>"+
			"- <a href='http://www.famfamfam.com/lab/icons/silk/'>FamFamFam &quot;Silk&quot; icon set</a><br>"+
			"- <a href='https://code.ivysaur.me/qbolt'>QBolt homepage</a><br>",
	)
}

func (this *MainWindow) on_actionDisconnect_triggered() {
	top := this.lastContextSelection
	if top.Parent() != nil {
		return // somehow we didn't select a top-level item
	}

	bdb := GET_BDB(top)

	// Remove UI
	this.ui.bucketTree.ClearSelection()
	top.Delete()

	// Disconnect from DB
	bdb.Close()
}

func (this *MainWindow) on_bucketTree_customContextMenuRequested(pos *qt.QPoint) {

	itm := this.ui.bucketTree.ItemAt(pos)
	if itm == nil {
		return
	}

	this.lastContextSelection = itm

	if itm.Parent() != nil {
		// Child item, show the bucket menu
		this.bucketContext.Popup(this.ui.bucketTree.Viewport().MapToGlobal(pos))

	} else {
		// Top-level item, show the database menu
		this.databaseContext.Popup(this.ui.bucketTree.Viewport().MapToGlobal(pos))
	}
}

func (this *MainWindow) on_actionRefresh_buckets_triggered() {
	this.refreshBucketTree(this.lastContextSelection)
}

func (this *MainWindow) on_bucketTree_currentItemChanged(current, previous *qt.QTreeWidgetItem) {
	_ = previous // Q_UNUSED
	if current == nil {
		this.ui.stackedWidget.SetVisible(false)
		return
	}

	this.ui.stackedWidget.SetVisible(true)

	if current.Parent() == nil {
		// Selected a database
		this.ui.stackedWidget.SetCurrentWidget(this.ui.databasePage)
		this.ui.databasePropertiesArea.Clear()

		bdb := GET_BDB(current)
		stats, err := Bolt_DBStats(bdb)
		if err != nil {
			this.ui.databasePropertiesArea.SetPlainText(fmt.Sprintf("Error retrieving database statistics: %s", err.Error()))
		} else {
			this.ui.databasePropertiesArea.SetPlainText(stats)
		}

		// Clean up foreign areas
		this.ui.bucketPropertiesArea.Clear()
		this.ui.bucketData.Clear()

	} else {
		// Selected a bucket

		this.ui.stackedWidget.SetCurrentWidget(this.ui.bucketPage)
		this.ui.bucketPropertiesArea.Clear()

		ws := this.getSelection(current)

		stats, err := Bolt_BucketStats(ws.bdb, ws.browse)
		if err != nil {
			this.ui.bucketPropertiesArea.SetPlainText(fmt.Sprintf("Error retrieving bucket statistics: %s", err.Error()))
		} else {
			this.ui.bucketPropertiesArea.SetPlainText(stats)
		}

		// Load the data tab
		this.refreshData(ws.bdb, ws.browse)

		// Clean up foreign areas
		this.ui.databasePropertiesArea.Clear()
	}
}

func (this *MainWindow) refreshData(bdb *bolt.DB, browse []string) {
	// Load the data tab
	this.ui.bucketData.Clear()

	err := Bolt_ListItems(bdb, browse, func(lii ListItemInfo) error {
		itm := qt.NewQTreeWidgetItem()
		itm.SetText(0, getDisplayName(lii.Name))
		itm.SetData(0, BinaryDataRole, qt.NewQVariant15(MakeQByteArray(lii.Name)))
		itm.SetText(1, fmt.Sprintf("%d", lii.DataLen))
		this.ui.bucketData.AddTopLevelItem(itm)
		return nil
	})

	if err != nil {
		this.alert(fmt.Sprintf("Error listing bucket content: %s", err.Error()))
		return
	}

	this.ui.bucketData.ResizeColumnToContents(0)
	this.on_bucketData_itemSelectionChanged()
}

func (this *MainWindow) on_actionClear_selection_triggered() {
	this.ui.bucketTree.SetCurrentItem(nil)
}

type windowSelection struct {
	itm    *qt.QTreeWidgetItem
	top    *qt.QTreeWidgetItem
	browse []string
	bdb    *bolt.DB
}

func (this *MainWindow) getWindowSelection() (windowSelection, bool) {

	itm := this.ui.bucketTree.CurrentItem()
	if itm == nil {
		return windowSelection{}, false // No selection
	}

	return this.getSelection(itm), true
}

func (this *MainWindow) getSelection(itm *qt.QTreeWidgetItem) windowSelection {

	top := itm

	var browse []string
	for {
		if top.Parent() == nil {
			break
		} else {
			browse = append(browse, FromQByteArray(top.Data(0, BinaryDataRole).ToByteArray()))
			top = top.Parent()
		}
	}

	ReverseSlice(browse)

	bdb := GET_BDB(top)

	return windowSelection{itm: itm, top: top, browse: browse, bdb: bdb}
}

func (this *MainWindow) openEditor(bdb *bolt.DB, saveAs []string, saveAsKey string, currentContent []byte) {
	iw := NewItemWindowUi()

	iw.contentArea.SetPlainText(string(currentContent))
	iw.ItemWindow.SetWindowTitle(getDisplayName(saveAsKey))
	iw.ItemWindow.SetWindowModality(qt.ApplicationModal) // we need this - otherwise we'll refresh a possibly-changed area after saving
	iw.ItemWindow.OnFinished(func(exitCode int) {
		if exitCode == int(qt.QDialog__Accepted) {

			err := Bolt_SetItem(bdb, saveAs, saveAsKey, iw.contentArea.ToPlainText())
			if err != nil {
				this.alert(fmt.Sprintf("Error saving item content: %s", err.Error()))
			}

			this.refreshData(bdb, saveAs)
		}
		iw.ItemWindow.DeleteLater()
	})

	iw.ItemWindow.Show()
}

func (this *MainWindow) on_bucketData_doubleClicked(index *qt.QModelIndex) {
	ws, ok := this.getWindowSelection()
	if !ok {
		return // no selection
	}

	// Get item key

	model := index.Model()
	key := FromQByteArray(model.Data2(model.Index(index.Row(), 0), BinaryDataRole).ToByteArray())

	// DB lookup
	content, err := Bolt_GetItem(ws.bdb, ws.browse, key)
	if err != nil {
		this.alert(fmt.Sprintf("Error loading item content: %s", err.Error()))
		return
	}

	this.openEditor(ws.bdb, ws.browse, key, []byte(content))
}

func (this *MainWindow) on_actionAdd_bucket_triggered() {
	ws, ok := this.getWindowSelection()
	if !ok {
		return // no selection
	}

	// Prompt for bucket name

	name := qt.QInputDialog_GetText(this.Widget(), "New bucket", "Enter a key for the new bucket:")
	if len(name) == 0 {
		return
	}

	// Create
	err := Bolt_CreateBucket(ws.bdb, ws.browse, name)
	if err != nil {
		this.alert(fmt.Sprintf("Error creating bucket: %s", err.Error()))
		return
	}

	// Refresh bucket list
	this.refreshBucketTree(ws.itm) // sub-tree only
	this.ui.bucketTree.ExpandItem(ws.itm)
}

func (this *MainWindow) on_actionDelete_bucket_triggered() {
	ws, ok := this.getWindowSelection()
	if !ok {
		return // no selection
	}

	// Prompt for confirmation
	bucketToDelete := FromQByteArray(ws.itm.Data(0, BinaryDataRole).ToByteArray())
	if qt.QMessageBox_Question4(
		this.Widget(),
		"Delete bucket",
		fmt.Sprintf("Are you sure you want to remove the bucket '%s'?", getDisplayName(bucketToDelete)),
		qt.QMessageBox__Yes,
		qt.QMessageBox__Cancel,
	) != int(qt.QMessageBox__Yes) {
		return
	}

	parent := ws.itm.Parent()

	// One level down

	if len(ws.browse) > 0 {
		ws.browse = ws.browse[0 : len(ws.browse)-1]
	}

	err := Bolt_DeleteBucket(ws.bdb, ws.browse, bucketToDelete)
	if err != nil {
		this.alert(fmt.Sprintf("Error removing bucket: %s", err.Error()))
		return
	}

	// Refresh bucket list
	this.refreshBucketTree(parent) // sub-tree only
	this.ui.bucketTree.ExpandItem(parent)
	this.ui.bucketTree.SetCurrentItem(parent)
}

func (this *MainWindow) on_AddDataButton_clicked() {
	ws, ok := this.getWindowSelection()
	if !ok {
		return // no selection
	}

	// Prompt for bucket name

	name := qt.QInputDialog_GetText(this.Widget(), "New item", "Enter a key for the new item:")
	if len(name) == 0 {
		return
	}

	this.openEditor(ws.bdb, ws.browse, name, []byte(""))
}

func (this *MainWindow) on_DeleteDataButton_clicked() {
	ws, ok := this.getWindowSelection()
	if !ok {
		return // no selection
	}

	selection := this.ui.bucketData.SelectedItems()
	if len(selection) == 0 {
		return // nothing to do
	}

	// Prompt for confirmation
	if qt.QMessageBox_Question4(this.Widget(), "Delete items", fmt.Sprintf("Are you sure you want to remove %d item(s)?", len(selection)), qt.QMessageBox__Yes, qt.QMessageBox__Cancel) != int(qt.QMessageBox__Yes) {
		return
	}

	var i int = len(selection)
	for i > 0 {
		err := Bolt_DeleteItem(ws.bdb, ws.browse, FromQByteArray(selection[i-1].Data(0, BinaryDataRole).ToByteArray()))
		if err != nil {
			this.alert(fmt.Sprintf("Error removing item: %s", err.Error()))
			return
		}
		i -= 1
	}

	this.refreshData(ws.bdb, ws.browse)
}

func (this *MainWindow) on_bucketData_itemSelectionChanged() {
	this.ui.DeleteDataButton.SetEnabled(len(this.ui.bucketData.SelectedItems()) > 0)
}