package xlsx

import (
	"errors"
	"fmt"
	"strconv"
)

// Sheet is a high level structure intended to provide user access to
// the contents of a particular sheet within an XLSX file.
type Sheet struct {
	Name        string
	File        *File
	Rows        []*Row
	Cols        []*Col
	MaxRow      int
	MaxCol      int
	Hidden      bool
	Selected    bool
	SheetViews  []SheetView
	SheetFormat SheetFormat
	AutoFilter  *AutoFilter
}

type SheetView struct {
	Pane *Pane
}

type Pane struct {
	XSplit      float64
	YSplit      float64
	TopLeftCell string
	ActivePane  string
	State       string // Either "split" or "frozen"
}

type SheetFormat struct {
	DefaultColWidth  float64
	DefaultRowHeight float64
	OutlineLevelCol  uint8
	OutlineLevelRow  uint8
}

type AutoFilter struct {
	TopLeftCell     string
	BottomRightCell string
}

// Add a new Row to a Sheet
func (s *Sheet) AddRow() *Row {
	row := &Row{Sheet: s}
	s.Rows = append(s.Rows, row)
	if len(s.Rows) > s.MaxRow {
		s.MaxRow = len(s.Rows)
	}
	return row
}

// Add a new Row to a Sheet at a specific index
func (s *Sheet) AddRowAtIndex(index int) (*Row, error) {
	if index < 0 || index > len(s.Rows) {
		return nil, errors.New("AddRowAtIndex: index out of bounds")
	}
	row := &Row{Sheet: s}
	s.Rows = append(s.Rows, nil)

	if index < len(s.Rows) {
		copy(s.Rows[index+1:], s.Rows[index:])
	}
	s.Rows[index] = row
	if len(s.Rows) > s.MaxRow {
		s.MaxRow = len(s.Rows)
	}
	return row, nil
}

// Removes a row at a specific index
func (s *Sheet) RemoveRowAtIndex(index int) error {
	if index < 0 || index >= len(s.Rows) {
		return errors.New("RemoveRowAtIndex: index out of bounds")
	}
	s.Rows = append(s.Rows[:index], s.Rows[index+1:]...)
	return nil
}

// Make sure we always have as many Rows as we do cells.
func (s *Sheet) maybeAddRow(rowCount int) {
	if rowCount > s.MaxRow {
		loopCnt := rowCount - s.MaxRow
		for i := 0; i < loopCnt; i++ {

			row := &Row{Sheet: s}
			s.Rows = append(s.Rows, row)
		}
		s.MaxRow = rowCount
	}
}

// Make sure we always have as many Rows as we do cells.
func (s *Sheet) Row(idx int) *Row {
	s.maybeAddRow(idx + 1)
	return s.Rows[idx]
}

// Make sure we always have as many Cols as we do cells.
func (s *Sheet) maybeAddCol(cellCount int) {
	if cellCount > s.MaxCol {
		loopCnt := cellCount - s.MaxCol
		currIndex := s.MaxCol + 1
		for i := 0; i < loopCnt; i++ {

			col := &Col{
				style:     NewStyle(),
				Min:       currIndex,
				Max:       currIndex,
				Hidden:    false,
				Collapsed: false}
			s.Cols = append(s.Cols, col)
			currIndex++
		}

		s.MaxCol = cellCount
	}
}

// Make sure we always have as many Cols as we do cells.
func (s *Sheet) Col(idx int) *Col {
	s.maybeAddCol(idx + 1)
	return s.Cols[idx]
}

// Get a Cell by passing it's cartesian coordinates (zero based) as
// row and column integer indexes.
//
// For example:
//
//    cell := sheet.Cell(0,0)
//
// ... would set the variable "cell" to contain a Cell struct
// containing the data from the field "A1" on the spreadsheet.
func (sh *Sheet) Cell(row, col int) *Cell {

	// If the user requests a row beyond what we have, then extend.
	for len(sh.Rows) <= row {
		sh.AddRow()
	}

	r := sh.Rows[row]
	for len(r.Cells) <= col {
		r.AddCell()
	}

	return r.Cells[col]
}

//Set the width of a single column or multiple columns.
func (s *Sheet) SetColWidth(startcol, endcol int, width float64) error {
	if startcol > endcol {
		return fmt.Errorf("Could not set width for range %d-%d: startcol must be less than endcol.", startcol, endcol)
	}
	end := endcol + 1
	s.maybeAddCol(end)
	for ; startcol < end; startcol++ {
		s.Cols[startcol].Width = width
	}
	return nil
}

// When merging cells, the cell may be the 'original' or the 'covered'.
// First, figure out which cells are merge starting points. Then create
// the necessary cells underlying the merge area.
// Then go through all the underlying cells and apply the appropriate
// border, based on the original cell.
func (s *Sheet) handleMerged() {
	merged := make(map[string]*Cell)

	for r, row := range s.Rows {
		for c, cell := range row.Cells {
			if cell.HMerge > 0 || cell.VMerge > 0 {
				coord := GetCellIDStringFromCoords(c, r)
				merged[coord] = cell
			}
		}
	}

	// This loop iterates over all cells that should be merged and applies the correct
	// borders to them depending on their position. If any cells required by the merge
	// are missing, they will be allocated by s.Cell().
	for key, cell := range merged {

		maincol, mainrow, _ := GetCoordsFromCellIDString(key)
		for rownum := 0; rownum <= cell.VMerge; rownum++ {
			for colnum := 0; colnum <= cell.HMerge; colnum++ {
				// make cell
				s.Cell(mainrow+rownum, maincol+colnum)

			}
		}
	}
}

// Dump sheet to its XML representation, intended for internal use only
func (s *Sheet) makeXLSXSheet(refTable *RefTable, styles *xlsxStyleSheet) *xlsxWorksheet {
	worksheet := newXlsxWorksheet()
	xSheet := xlsxSheetData{}
	maxRow := 0
	maxCell := 0
	var maxLevelCol, maxLevelRow uint8

	// Scan through the sheet and see if there are any merged cells. If there
	// are, we may need to extend the size of the sheet. There needs to be
	// phantom cells underlying the area covered by the merged cell
	s.handleMerged()

	for index, sheetView := range s.SheetViews {
		if sheetView.Pane != nil {
			worksheet.SheetViews.SheetView[index].Pane = &xlsxPane{
				XSplit:      sheetView.Pane.XSplit,
				YSplit:      sheetView.Pane.YSplit,
				TopLeftCell: sheetView.Pane.TopLeftCell,
				ActivePane:  sheetView.Pane.ActivePane,
				State:       sheetView.Pane.State,
			}

		}
	}

	if s.Selected {
		worksheet.SheetViews.SheetView[0].TabSelected = true
	}

	if s.SheetFormat.DefaultRowHeight != 0 {
		worksheet.SheetFormatPr.DefaultRowHeight = s.SheetFormat.DefaultRowHeight
	}
	worksheet.SheetFormatPr.DefaultColWidth = s.SheetFormat.DefaultColWidth

	colsXfIdList := make([]int, len(s.Cols))
	for c, col := range s.Cols {
		XfId := 0
		if col.Min == 0 {
			col.Min = 1
		}
		if col.Max == 0 {
			col.Max = 1
		}
		style := col.GetStyle()
		//col's style always not nil
		if style != nil {
			xNumFmt := styles.newNumFmt(col.numFmt)
			XfId = handleStyleForXLSX(style, xNumFmt.NumFmtId, styles)
		}
		colsXfIdList[c] = XfId

		var customWidth bool
		if col.Width == 0 {
			col.Width = ColWidth
			customWidth = false
		} else {
			customWidth = true
		}
		// When the cols content is empty, the cols flag is not output in the xml file.
		if worksheet.Cols == nil {
			worksheet.Cols = &xlsxCols{Col: []xlsxCol{}}
		}
		worksheet.Cols.Col = append(worksheet.Cols.Col,
			xlsxCol{Min: col.Min,
				Max:          col.Max,
				Hidden:       col.Hidden,
				Width:        col.Width,
				CustomWidth:  customWidth,
				Collapsed:    col.Collapsed,
				OutlineLevel: col.OutlineLevel,
				Style:        XfId,
			})

		if col.OutlineLevel > maxLevelCol {
			maxLevelCol = col.OutlineLevel
		}
		if nil != col.DataValidation {
			if nil == worksheet.DataValidations {
				worksheet.DataValidations = &xlsxCellDataValidations{}
			}
			colName := ColIndexToLetters(c)
			for _, dd := range col.DataValidation {
				if dd.minRow == dd.maxRow {
					dd.Sqref = colName + RowIndexToString(dd.minRow)
				} else {
					dd.Sqref = colName + RowIndexToString(dd.minRow) + cellRangeChar + colName + RowIndexToString(dd.maxRow)
				}
				worksheet.DataValidations.DataValidation = append(worksheet.DataValidations.DataValidation, dd)

			}
			worksheet.DataValidations.Count = len(worksheet.DataValidations.DataValidation)
		}
	}

	for r, row := range s.Rows {
		if r > maxRow {
			maxRow = r
		}
		xRow := xlsxRow{}
		xRow.R = r + 1
		if row.isCustom {
			xRow.CustomHeight = true
			xRow.Ht = fmt.Sprintf("%g", row.Height)
		}
		xRow.OutlineLevel = row.OutlineLevel
		if row.OutlineLevel > maxLevelRow {
			maxLevelRow = row.OutlineLevel
		}
		for c, cell := range row.Cells {
			XfId := colsXfIdList[c]

			// generate NumFmtId and add new NumFmt
			xNumFmt := styles.newNumFmt(cell.NumFmt)

			style := cell.style
			if style != nil {
				XfId = handleStyleForXLSX(style, xNumFmt.NumFmtId, styles)
			} else if len(cell.NumFmt) > 0 && !compareFormatString(s.Cols[c].numFmt, cell.NumFmt) {
				XfId = handleNumFmtIdForXLSX(xNumFmt.NumFmtId, styles)
			}

			if c > maxCell {
				maxCell = c
			}
			xC := xlsxC{
				S: XfId,
				R: GetCellIDStringFromCoords(c, r),
			}
			if cell.formula != "" {
				xC.F = &xlsxF{Content: cell.formula}
			}
			switch cell.cellType {
			case CellTypeInline:
				// Inline strings are turned into shared strings since they are more efficient.
				// This is what Excel does as well.
				fallthrough
			case CellTypeString:
				if len(cell.Value) > 0 {
					xC.V = strconv.Itoa(refTable.AddString(cell.Value))
				}
				xC.T = "s"
			case CellTypeNumeric:
				// Numeric is the default, so the type can be left blank
				xC.V = cell.Value
			case CellTypeBool:
				xC.V = cell.Value
				xC.T = "b"
			case CellTypeError:
				xC.V = cell.Value
				xC.T = "e"
			case CellTypeDate:
				xC.V = cell.Value
				xC.T = "d"
			case CellTypeStringFormula:
				xC.V = cell.Value
				xC.T = "str"
			default:
				panic(errors.New("unknown cell type cannot be marshaled"))
			}

			xRow.C = append(xRow.C, xC)
			if nil != cell.DataValidation {
				if nil == worksheet.DataValidations {
					worksheet.DataValidations = &xlsxCellDataValidations{}
				}
				cell.DataValidation.Sqref = xC.R
				worksheet.DataValidations.DataValidation = append(worksheet.DataValidations.DataValidation, cell.DataValidation)
				worksheet.DataValidations.Count = len(worksheet.DataValidations.DataValidation)
			}

			if cell.HMerge > 0 || cell.VMerge > 0 {
				// r == rownum, c == colnum
				mc := xlsxMergeCell{}
				start := GetCellIDStringFromCoords(c, r)
				endCol := c + cell.HMerge
				endRow := r + cell.VMerge
				end := GetCellIDStringFromCoords(endCol, endRow)
				mc.Ref = start + cellRangeChar + end
				if worksheet.MergeCells == nil {
					worksheet.MergeCells = &xlsxMergeCells{}
				}
				worksheet.MergeCells.Cells = append(worksheet.MergeCells.Cells, mc)
			}
		}
		xSheet.Row = append(xSheet.Row, xRow)
	}

	// Update sheet format with the freshly determined max levels
	s.SheetFormat.OutlineLevelCol = maxLevelCol
	s.SheetFormat.OutlineLevelRow = maxLevelRow
	// .. and then also apply this to the xml worksheet
	worksheet.SheetFormatPr.OutlineLevelCol = s.SheetFormat.OutlineLevelCol
	worksheet.SheetFormatPr.OutlineLevelRow = s.SheetFormat.OutlineLevelRow

	if worksheet.MergeCells != nil {
		worksheet.MergeCells.Count = len(worksheet.MergeCells.Cells)
	}

	if s.AutoFilter != nil {
		worksheet.AutoFilter = &xlsxAutoFilter{Ref: fmt.Sprintf("%v:%v", s.AutoFilter.TopLeftCell, s.AutoFilter.BottomRightCell)}
	}

	worksheet.SheetData = xSheet
	dimension := xlsxDimension{}
	dimension.Ref = "A1:" + GetCellIDStringFromCoords(maxCell, maxRow)
	if dimension.Ref == "A1:A1" {
		dimension.Ref = "A1"
	}
	worksheet.Dimension = dimension
	return worksheet
}

func handleStyleForXLSX(style *Style, NumFmtId int, styles *xlsxStyleSheet) (XfId int) {
	xFont, xFill, xBorder, xCellXf := style.makeXLSXStyleElements()
	fontId := styles.addFont(xFont)
	fillId := styles.addFill(xFill)

	// HACK - adding light grey fill, as in OO and Google
	greyfill := xlsxFill{}
	greyfill.PatternFill.PatternType = "lightGray"
	styles.addFill(greyfill)

	borderId := styles.addBorder(xBorder)
	xCellXf.FontId = fontId
	xCellXf.FillId = fillId
	xCellXf.BorderId = borderId
	xCellXf.NumFmtId = NumFmtId
	// apply the numFmtId when it is not the default cellxf
	if xCellXf.NumFmtId > 0 {
		xCellXf.ApplyNumberFormat = true
	}

	xCellXf.Alignment.Horizontal = style.Alignment.Horizontal
	xCellXf.Alignment.Indent = style.Alignment.Indent
	xCellXf.Alignment.ShrinkToFit = style.Alignment.ShrinkToFit
	xCellXf.Alignment.TextRotation = style.Alignment.TextRotation
	xCellXf.Alignment.Vertical = style.Alignment.Vertical
	xCellXf.Alignment.WrapText = style.Alignment.WrapText

	XfId = styles.addCellXf(xCellXf)
	return
}

func handleNumFmtIdForXLSX(NumFmtId int, styles *xlsxStyleSheet) (XfId int) {
	xCellXf := makeXLSXCellElement()
	xCellXf.NumFmtId = NumFmtId
	if xCellXf.NumFmtId > 0 {
		xCellXf.ApplyNumberFormat = true
	}
	XfId = styles.addCellXf(xCellXf)
	return
}