import { saveAs } from 'file-saver'
import { SSF, utils, write } from 'xlsx'

import type { BookType } from 'xlsx'

function generateArray(table: any) {
    const out: any[] = []
    const rows = table.querySelectorAll('tr')
    const ranges: any[] = []
    for (const [R, row] of rows.entries()) {
        const outRow: any[] = []
        const columns = row.querySelectorAll('td')
        for (const cell of columns) {
            let colspan = cell.getAttribute('colspan')
            let rowspan = cell.getAttribute('rowspan')
            let cellValue = cell.innerText
            if (cellValue !== '' && cellValue === +cellValue)
                cellValue = +cellValue
            ranges.forEach((range) => {
                if (
                    R >= range.s.r &&
                    R <= range.e.r &&
                    outRow.length >= range.s.c &&
                    outRow.length <= range.e.c
                ) {
                    for (let i = 0; i <= range.e.c - range.s.c; ++i)
                        outRow.push(null)
                }
            })
            if (rowspan || colspan) {
                rowspan = rowspan || 1
                colspan = colspan || 1
                ranges.push({
                    s: {
                        r: R,
                        c: outRow.length,
                    },
                    e: {
                        r: R + rowspan - 1,
                        c: outRow.length + colspan - 1,
                    },
                })
            }

            outRow.push(cellValue !== '' ? cellValue : null)

            if (colspan) for (let k = 0; k < colspan - 1; ++k) outRow.push(null)
        }
        out.push(outRow)
    }
    return [out, ranges]
}

function datenum(v: any, date1904 = null) {
    if (date1904) {
        v += 1462
    }
    const epoch = Date.parse(v)
    return (
        (epoch - (new Date(Date.UTC(1899, 11, 30)) as any)) /
        (24 * 60 * 60 * 1000)
    )
}

function sheet_from_array_of_arrays(data: any) {
    const ws: any = {}
    const range = {
        s: {
            c: 10000000,
            r: 10000000,
        },
        e: {
            c: 0,
            r: 0,
        },
    }
    for (let R = 0; R !== data.length; ++R) {
        for (let C = 0; C !== data[R].length; ++C) {
            if (range.s.r > R) range.s.r = R
            if (range.s.c > C) range.s.c = C
            if (range.e.r < R) range.e.r = R
            if (range.e.c < C) range.e.c = C
            const cell: any = {
                v: data[R][C],
            }
            if (cell.v === null) continue
            const cellRef = utils.encode_cell({
                c: C,
                r: R,
            })

            if (typeof cell.v === 'number') cell.t = 'n'
            else if (typeof cell.v === 'boolean') cell.t = 'b'
            else if (cell.v instanceof Date) {
                cell.t = 'n'
                cell.z = (SSF as any)._table[14]
                cell.v = datenum(cell.v)
            } else cell.t = 's'

            ws[cellRef] = cell
        }
    }
    if (range.s.c < 10000000) ws['!ref'] = utils.encode_range(range)
    return ws
}

class Workbook {
    public SheetNames: any[] = []
    public Sheets: any = {}
}

function s2ab(s: any) {
    const buf = new ArrayBuffer(s.length)
    const view = new Uint8Array(buf)
    for (let i = 0; i !== s.length; ++i) view[i] = s.charCodeAt(i) & 0xff
    return buf
}

export function export_table_to_excel(id: any) {
    const theTable = document.getElementById(id)
    const oo = generateArray(theTable)
    const ranges = oo[1]

    const data = oo[0]
    const wsName = 'SheetJS'

    const wb = new Workbook()
    const ws = sheet_from_array_of_arrays(data)

    ws['!merges'] = ranges

    wb.SheetNames.push(wsName)
    wb.Sheets[wsName] = ws

    const wbout = write(wb, {
        bookType: 'xlsx',
        bookSST: false,
        type: 'binary',
    })

    saveAs(
        new Blob([s2ab(wbout)], {
            type: 'application/octet-stream',
        }),
        'test.xlsx'
    )
}

export function export_json_to_excel(
    {
        multiHeader = [],
        header,
        data,
        filename,
        merges = [],
        autoWidth = true,
        bookType = 'xlsx',
    } = {
        header: {},
        data: [] as any[],
        filename: '',
    }
) {
    /* original data */
    filename = filename || 'excel-list'
    data = [...data]
    data.unshift(header)

    for (let i = multiHeader.length - 1; i > -1; i--) {
        data.unshift(multiHeader[i])
    }

    const wsName = 'SheetJS'
    const wb = new Workbook()
    const ws = sheet_from_array_of_arrays(data)

    if (merges.length > 0) {
        if (!ws['!merges']) {
            ws['!merges'] = []
        }
        merges.forEach((item) => {
            ws['!merges'].push(utils.decode_range(item))
        })
    }

    if (autoWidth) {
        const colWidth = data.map((row) =>
            row.map((val: any) => {
                if (val === null) {
                    return {
                        wch: 10,
                    }
                } else if (val.toString().charCodeAt(0) > 255) {
                    return {
                        wch: val.toString().length * 2,
                    }
                } else {
                    return {
                        wch: val.toString().length,
                    }
                }
            })
        )
        const result = colWidth[0]
        for (let i = 1; i < colWidth.length; i++) {
            for (let j = 0; j < colWidth[i].length; j++) {
                if (result[j]['wch'] < colWidth[i][j]['wch']) {
                    result[j]['wch'] = colWidth[i][j]['wch']
                }
            }
        }
        ws['!cols'] = result
    }

    wb.SheetNames.push(wsName)
    wb.Sheets[wsName] = ws

    const wbout = write(wb, {
        bookType: bookType as BookType,
        bookSST: false,
        type: 'binary',
    })
    saveAs(
        new Blob([s2ab(wbout)], {
            type: 'application/octet-stream',
        }),
        `${filename}.${bookType}`
    )
}