# -*- coding: utf-8 -*-

"""
/***************************************************************************
Name                 : DB Manager
Description          : Database manager plugin for QGIS
Date                 : Oct 13, 2011
copyright            : (C) 2011 by Giuseppe Sucameli
email                : brush.tyler@gmail.com

The content of this file is based on
- PG_Manager by Martin Dobias (GPLv2 license)
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
"""
from builtins import str
from builtins import range

from qgis.PyQt.QtCore import Qt, QModelIndex
from qgis.PyQt.QtWidgets import QItemDelegate, QComboBox, QDialog, QPushButton, QDialogButtonBox, QMessageBox, QApplication
from qgis.PyQt.QtCore import QItemSelectionModel, pyqtSignal

from qgis.utils import OverrideCursor

from .db_plugins.data_model import TableFieldsModel
from .db_plugins.plugin import DbError, ConnectionError
from .dlg_db_error import DlgDbError

from .ui.ui_DlgCreateTable import Ui_DbManagerDlgCreateTable as Ui_Dialog


class TableFieldsDelegate(QItemDelegate):

    """ delegate with some special item editors """

    columnNameChanged = pyqtSignal()

    def __init__(self, field_types, parent=None):
        QItemDelegate.__init__(self, parent)
        self.fieldTypes = field_types

    def createEditor(self, parent, option, index):
        # special combobox for field type
        if index.column() == 1:
            cbo = QComboBox(parent)
            cbo.setEditable(True)
            cbo.setFrame(False)
            for item in self.fieldTypes:
                cbo.addItem(item)
            return cbo
        return QItemDelegate.createEditor(self, parent, option, index)

    def setEditorData(self, editor, index):
        """ load data from model to editor """
        m = index.model()
        if index.column() == 1:
            txt = m.data(index, Qt.DisplayRole)
            editor.setEditText(txt)
        else:
            # use default
            QItemDelegate.setEditorData(self, editor, index)

    def setModelData(self, editor, model, index):
        """ save data from editor back to model """
        if index.column() == 1:
            model.setData(index, editor.currentText())
        else:
            # use default
            QItemDelegate.setModelData(self, editor, model, index)
            if index.column() == 0:
                self.columnNameChanged.emit()


class DlgCreateTable(QDialog, Ui_Dialog):
    GEOM_TYPES = ["POINT", "LINESTRING", "POLYGON", "MULTIPOINT", "MULTILINESTRING", "MULTIPOLYGON",
                  "GEOMETRYCOLLECTION"]

    def __init__(self, item, parent=None):
        QDialog.__init__(self, parent)
        self.item = item
        self.setupUi(self)

        self.db = self.item.database()
        self.schemas = self.db.schemas()
        self.hasSchemas = self.schemas is not None
        self.fieldTypes = self.db.connector.fieldTypes()

        m = TableFieldsModel(self, True)  # it's editable
        self.fields.setModel(m)
        self.fields.setColumnHidden(3, True)  # hide Default column

        d = TableFieldsDelegate(self.fieldTypes, self)
        self.fields.setItemDelegate(d)

        self.fields.setColumnWidth(0, 140)
        self.fields.setColumnWidth(1, 140)
        self.fields.setColumnWidth(2, 50)

        b = QPushButton(self.tr("&Create"))
        self.buttonBox.addButton(b, QDialogButtonBox.ActionRole)

        self.btnAddField.clicked.connect(self.addField)
        self.btnDeleteField.clicked.connect(self.deleteField)
        self.btnFieldUp.clicked.connect(self.fieldUp)
        self.btnFieldDown.clicked.connect(self.fieldDown)
        b.clicked.connect(self.createTable)

        self.chkGeomColumn.clicked.connect(self.updateUi)

        self.fields.selectionModel().selectionChanged.connect(self.updateUiFields)
        d.columnNameChanged.connect(self.updatePkeyCombo)

        self.populateSchemas()
        self.updateUi()
        self.updateUiFields()

    def populateSchemas(self):
        self.cboSchema.clear()
        if not self.hasSchemas:
            self.hideSchemas()
            return

        index = -1
        for schema in self.schemas:
            self.cboSchema.addItem(schema.name)
            if hasattr(self.item, 'schema') and schema.name == self.item.schema().name:
                index = self.cboSchema.count() - 1
        self.cboSchema.setCurrentIndex(index)

    def hideSchemas(self):
        self.cboSchema.setEnabled(False)

    def updateUi(self):
        useGeom = self.chkGeomColumn.isChecked()
        self.cboGeomType.setEnabled(useGeom)
        self.editGeomColumn.setEnabled(useGeom)
        self.spinGeomDim.setEnabled(useGeom)
        self.editGeomSrid.setEnabled(useGeom)
        self.chkSpatialIndex.setEnabled(useGeom)

    def updateUiFields(self):
        fld = self.selectedField()
        if fld is not None:
            up_enabled = (fld != 0)
            down_enabled = (fld != self.fields.model().rowCount() - 1)
            del_enabled = True
        else:
            up_enabled, down_enabled, del_enabled = False, False, False
        self.btnFieldUp.setEnabled(up_enabled)
        self.btnFieldDown.setEnabled(down_enabled)
        self.btnDeleteField.setEnabled(del_enabled)

    def updatePkeyCombo(self, selRow=None):
        """ called when list of columns changes. if 'sel' is None, it keeps current index """

        if selRow is None:
            selRow = self.cboPrimaryKey.currentIndex()

        self.cboPrimaryKey.clear()

        m = self.fields.model()
        for row in range(m.rowCount()):
            name = m.data(m.index(row, 0))
            self.cboPrimaryKey.addItem(name)

        self.cboPrimaryKey.setCurrentIndex(selRow)

    def addField(self):
        """ add new field to the end of field table """
        m = self.fields.model()
        newRow = m.rowCount()
        m.insertRows(newRow, 1)

        indexName = m.index(newRow, 0, QModelIndex())
        indexType = m.index(newRow, 1, QModelIndex())
        indexNull = m.index(newRow, 2, QModelIndex())

        m.setData(indexName, "new_field")
        colType = self.fieldTypes[0]
        if newRow == 0:
            # adding the first row, use auto-incrementing column type if any
            if "serial" in self.fieldTypes:  # PostgreSQL
                colType = "serial"
        m.setData(indexType, colType)
        m.setData(indexNull, None, Qt.DisplayRole)
        m.setData(indexNull, Qt.Unchecked, Qt.CheckStateRole)

        # selects the new row
        sel = self.fields.selectionModel()
        sel.select(indexName, QItemSelectionModel.Rows | QItemSelectionModel.ClearAndSelect)

        # starts editing
        self.fields.edit(indexName)

        self.updatePkeyCombo(0 if newRow == 0 else None)

    def selectedField(self):
        sel = self.fields.selectedIndexes()
        if len(sel) < 1:
            return None
        return sel[0].row()

    def deleteField(self):
        """ delete selected field """
        row = self.selectedField()
        if row is None:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("No field selected."))
        else:
            self.fields.model().removeRows(row, 1)

        self.updatePkeyCombo()

    def fieldUp(self):
        """ move selected field up """
        row = self.selectedField()
        if row is None:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("No field selected."))
            return
        if row == 0:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("Field is already at the top."))
            return

        # take row and reinsert it
        rowdata = self.fields.model().takeRow(row)
        self.fields.model().insertRow(row - 1, rowdata)

        # set selection again
        index = self.fields.model().index(row - 1, 0, QModelIndex())
        self.fields.selectionModel().select(index, QItemSelectionModel.Rows | QItemSelectionModel.ClearAndSelect)

        self.updatePkeyCombo()

    def fieldDown(self):
        """ move selected field down """
        row = self.selectedField()
        if row is None:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("No field selected."))
            return
        if row == self.fields.model().rowCount() - 1:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("Field is already at the bottom."))
            return

        # take row and reinsert it
        rowdata = self.fields.model().takeRow(row)
        self.fields.model().insertRow(row + 1, rowdata)

        # set selection again
        index = self.fields.model().index(row + 1, 0, QModelIndex())
        self.fields.selectionModel().select(index, QItemSelectionModel.Rows | QItemSelectionModel.ClearAndSelect)

        self.updatePkeyCombo()

    def createTable(self):
        """ create table with chosen fields, optionally add a geometry column """
        if not self.hasSchemas:
            schema = None
        else:
            schema = str(self.cboSchema.currentText())
            if len(schema) == 0:
                QMessageBox.information(self, self.tr("DB Manager"), self.tr("A valid schema must be selected first."))
                return

        table = str(self.editName.text())
        if len(table) == 0:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("A valid table name is required."))
            return

        m = self.fields.model()
        if m.rowCount() == 0:
            QMessageBox.information(self, self.tr("DB Manager"), self.tr("At least one field is required."))
            return

        useGeomColumn = self.chkGeomColumn.isChecked()
        if useGeomColumn:
            geomColumn = str(self.editGeomColumn.text())
            if len(geomColumn) == 0:
                QMessageBox.information(self, self.tr("DB Manager"), self.tr("A name is required for the geometry column."))
                return

            geomType = self.GEOM_TYPES[self.cboGeomType.currentIndex()]
            geomDim = self.spinGeomDim.value()
            try:
                geomSrid = int(self.editGeomSrid.text())
            except ValueError:
                geomSrid = 0
            useSpatialIndex = self.chkSpatialIndex.isChecked()

        flds = m.getFields()
        pk_index = self.cboPrimaryKey.currentIndex()
        if pk_index >= 0:
            flds[pk_index].primaryKey = True

        # commit to DB
        with OverrideCursor(Qt.WaitCursor):
            try:
                if not useGeomColumn:
                    self.db.createTable(table, flds, schema)
                else:
                    geom = geomColumn, geomType, geomSrid, geomDim, useSpatialIndex
                    self.db.createVectorTable(table, flds, geom, schema)

            except (ConnectionError, DbError) as e:
                DlgDbError.showError(e, self)
            return

        QMessageBox.information(self, self.tr("DB Manager"), self.tr("Table created successfully."))
