import { GridDto } from '@/proxy/form/models'
import {
  ImportPreviewData,
  ListFormImportDto,
  ListFormImportExecuteDto,
} from '@/proxy/imports/models'
import apiService from './api.service'

export class ImportService {
  private _uploadedFiles = new Map<string, File>()

  async generateTemplate(gridDto: GridDto, format: 'excel' | 'csv'): Promise<Blob> {
    const editableColumns = gridDto.columnFormats
      .filter((col) => col.permissionDto.i && col.fieldName !== 'Id')
      .sort((a, b) => a.listOrderNo - b.listOrderNo)

    if (format === 'excel') {
      // Create Excel-compatible content
      const headers = editableColumns.map((col) => col.captionName || col.fieldName)

      // Create a simple Excel XML format that works with Excel 2010+
      const excelContent = `<?xml version="1.0"?>
<Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet"
 xmlns:o="urn:schemas-microsoft-com:office:office"
 xmlns:x="urn:schemas-microsoft-com:office:excel"
 xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet"
 xmlns:html="http://www.w3.org/TR/REC-html40">
 <DocumentProperties xmlns="urn:schemas-microsoft-com:office:office">
  <Title>Import Template</Title>
 </DocumentProperties>
 <ExcelWorkbook xmlns="urn:schemas-microsoft-com:office:excel">
  <WindowHeight>12000</WindowHeight>
  <WindowWidth>15000</WindowWidth>
  <WindowTopX>240</WindowTopX>
  <WindowTopY>75</WindowTopY>
  <ProtectStructure>False</ProtectStructure>
  <ProtectWindows>False</ProtectWindows>
 </ExcelWorkbook>
 <Styles>
  <Style ss:ID="Default" ss:Name="Normal">
   <Alignment ss:Vertical="Bottom"/>
   <Borders/>
   <Font ss:FontName="Calibri" x:Family="Swiss" ss:Size="11" ss:Color="#000000"/>
   <Interior/>
   <NumberFormat/>
   <Protection/>
  </Style>
  <Style ss:ID="s62">
   <Font ss:FontName="Calibri" x:Family="Swiss" ss:Size="11" ss:Color="#000000" ss:Bold="1"/>
   <Interior ss:Color="#D9E1F2" ss:Pattern="Solid"/>
  </Style>
 </Styles>
 <Worksheet ss:Name="Import Template">
  <Table ss:ExpandedColumnCount="${
    headers.length
  }" ss:ExpandedRowCount="1000" x:FullColumns="1" x:FullRows="1" ss:DefaultRowHeight="15">
   <Row ss:AutoFitHeight="0" ss:Height="18">
${headers
  .map((header) => `    <Cell ss:StyleID="s62"><Data ss:Type="String">${header}</Data></Cell>`)
  .join('\n')}
   </Row>
  </Table>
  <WorksheetOptions xmlns="urn:schemas-microsoft-com:office:excel">
   <PageSetup>
    <Header x:Margin="0.3"/>
    <Footer x:Margin="0.3"/>
    <PageMargins x:Bottom="0.75" x:Left="0.7" x:Right="0.7" x:Top="0.75"/>
   </PageSetup>
   <Selected/>
   <Panes>
    <Pane>
     <Number>3</Number>
     <ActiveRow>1</ActiveRow>
     <ActiveCol>0</ActiveCol>
    </Pane>
   </Panes>
   <ProtectObjects>False</ProtectObjects>
   <ProtectScenarios>False</ProtectScenarios>
  </WorksheetOptions>
 </Worksheet>
</Workbook>`

      return new Blob([excelContent], {
        type: 'application/vnd.ms-excel',
      })
    } else {
      // CSV format
      const headers = editableColumns.map((col) => col.captionName || col.fieldName)
      const content = headers.join(',') + '\n'
      return new Blob([content], { type: 'text/csv' })
    }
  }

  downloadGenerateTemplate(blob: Blob, filename: string): void {
    const url = window.URL.createObjectURL(blob)
    const a = document.createElement('a')
    a.style.display = 'none'
    a.href = url
    a.download = filename
    // Set proper file extension for Excel files
    if (filename.endsWith('.xlsx') && blob.type === 'application/vnd.ms-excel') {
      a.download = filename.replace('.xlsx', '.xls')
    }
    document.body.appendChild(a)
    a.click()
    window.URL.revokeObjectURL(url)
    document.body.removeChild(a)
  }

  async uploadFile(file: File, listFormCode: string): Promise<ListFormImportDto> {
    const entity = await this.createSession(file, listFormCode)

    if (!entity.id) {
      throw new Error('Session ID not returned from server')
    }

    this._uploadedFiles.set(entity.id, file)

    return entity
  }

  async createSession(file: File, listFormCode: string): Promise<ListFormImportDto> {
    const formData = new FormData()
    formData.append('listFormCode', listFormCode)
    formData.append('file', file)
    formData.append('FileName', file.name)
    formData.append('ContentType', file.type)
    formData.append('ContentLength', file.size.toString())

    const response = await apiService.fetchData<ListFormImportDto>({
      url: `/api/app/list-form-import`,
      method: 'POST',
      data: formData as any,
    })

    return response.data
  }

  async getImportPreview(sessionId: string, gridDto?: GridDto): Promise<ImportPreviewData> {
    const file = this._uploadedFiles.get(sessionId)
    let actualData: any[] = []

    if (file) {
      try {
        actualData = await this.parseFileForPreview(file)
      } catch (error) {
        console.error('Error parsing file for preview:', error)
      }
    } else {
      console.log('No file found for session:', sessionId)
    }

    if (actualData.length === 0) {
      return {
        sessionId,
        headers: [],
        rows: [],
        totalRows: 0,
        columnMappings: [],
      }
    }

    const headers = Object.keys(actualData[0])
    const rows = actualData.map((row) => headers.map((header) => row[header] || ''))

    const columnMappings = headers.map((header) => {
      const matchingColumn = gridDto?.columnFormats.find(
        (col) => col.captionName === header || col.fieldName === header,
      )

      return {
        sourceColumn: header,
        targetField: matchingColumn?.fieldName || header.toLowerCase().replace(/\s+/g, ''),
        isRequired:
          matchingColumn?.validationRuleDto.some((rule) => rule.type === 'required') || false,
        dataType: matchingColumn?.dataType || this.inferDataType(header, actualData[0][header]),
      }
    })

    await this.updateSession(sessionId, {
      totalRows: rows.length,
      listFormCode: gridDto?.gridOptions.listFormCode || '',
    })

    return {
      sessionId,
      headers,
      rows,
      totalRows: rows.length,
      columnMappings,
      validationResults: [],
    }
  }

  async executeImport(
    sessionId: string,
    listFormCode: string,
    selectedRows?: number[],
  ): Promise<ListFormImportExecuteDto> {
    // Get the uploaded file data
    const uploadedFile = this._uploadedFiles.get(sessionId)
    if (!uploadedFile) {
      throw new Error(`No uploaded file found for session ${sessionId}`)
    }

    // Parse the file to get all data
    const allFileData = await this.parseFileForPreview(uploadedFile)

    // Get selected rows data based on selectedRows indices
    let selectedRowsData: any[] = []
    if (selectedRows && selectedRows.length > 0) {
      selectedRowsData = selectedRows
        .filter((index) => index >= 0 && index < allFileData.length)
        .map((index) => allFileData[index])
    } else {
      selectedRowsData = allFileData // If no specific rows selected, use all data
    }

    // Call backend API to execute import with selected rows data
    const response = await apiService.fetchData<ListFormImportExecuteDto>({
      url: `/api/app/list-form-import/execute`,
      method: 'POST',
      data: {
        sessionId: sessionId,
        listFormCode: listFormCode,
        selectedRowsData: selectedRowsData,
        selectedRowIndices: selectedRows || [],
      },
    })
    return response.data
  }

  async getListFormImport(sessionId: string): Promise<ListFormImportDto> {
    const response = await apiService.fetchData<ListFormImportDto>({
      url: `/api/app/list-form-import/${sessionId}`,
      method: 'GET',
    })

    return response.data
  }

  async getListFormImportByListFormCode(listFormCode: string): Promise<ListFormImportDto[]> {
    const response = await apiService.fetchData<ListFormImportDto[]>({
      url: `/api/app/list-form-import/by-list-form-code`,
      method: 'GET',
      params: { listFormCode },
    })

    return response.data
  }

  async getListFormImportExecutes(sessionId: string): Promise<ListFormImportExecuteDto[]> {
    const response = await apiService.fetchData<ListFormImportExecuteDto[]>({
      url: `/api/app/list-form-import/executes/${sessionId}`,
      method: 'GET',
    })

    return response.data
  }

  async deleteHistory(sessionId: string): Promise<void> {
    await apiService.fetchData<void>({
      url: `/api/app/list-form-import/${sessionId}`,
      method: 'DELETE',
    })
  }

  async updateSession(
    sessionId: string,
    payload: Partial<ListFormImportDto>,
  ): Promise<ListFormImportDto> {
    const response = await apiService.fetchData<ListFormImportDto>({
      url: `/api/app/list-form-import/${sessionId}`,
      method: 'PUT',
      data: payload, // body
    })

    return response.data
  }

  private async parseFileForPreview(file: File): Promise<any[]> {
    const extension = file.name.toLowerCase().split('.').pop()

    if (extension === 'csv') {
      return await this.parseCsvForPreview(file)
    } else if (extension === 'xls' || extension === 'xlsx') {
      return await this.parseExcelForPreview(file)
    }

    return []
  }

  private async parseCsvForPreview(file: File): Promise<any[]> {
    try {
      // Try multiple encodings to handle Turkish characters properly
      const content = await this.tryMultipleEncodings(file, [
        'UTF-8',
        'windows-1254',
        'iso-8859-9',
        'iso-8859-1',
      ])
      const lines = content.split(/\r?\n/).filter((line) => line.trim())

      if (lines.length < 2) {
        return []
      }

      const headers = this.parseCsvLine(lines[0]).map((header) =>
        this.fixTurkishCharacters(header.trim()),
      )
      const data: any[] = []

      // Parse all data rows (excluding header)
      for (let i = 1; i < lines.length; i++) {
        if (!lines[i].trim()) continue // Skip empty lines

        const values = this.parseCsvLine(lines[i])
        const row: any = {}

        headers.forEach((header, index) => {
          let value = values[index] ? values[index].trim() : ''
          // Fix Turkish character encoding issues
          value = this.fixTurkishCharacters(value)
          row[header] = value
        })

        data.push(row)
      }

      return data
    } catch (error) {
      console.error('Error parsing CSV:', error)
      return []
    }
  }

  private async parseExcelForPreview(file: File): Promise<any[]> {
    // Since we can't easily parse Excel files in the browser without a library,
    // we'll try to read it as text and extract what we can
    return new Promise((resolve) => {
      const reader = new FileReader()
      reader.onload = (e) => {
        try {
          const content = e.target?.result as string

          // Try to extract text content from Excel file
          // This is a basic approach - in production you'd use a proper Excel parsing library
          const textContent = this.extractTextFromExcel(content)

          if (textContent.length > 0) {
            resolve(textContent)
          }
        } catch (error) {
          console.error('Error parsing Excel:', error)
          resolve([])
        }
      }
      reader.readAsText(file, 'UTF-8')
    })
  }

  private extractTextFromExcel(content: string): any[] {
    try {
      const data: any[] = []

      // Parse Excel XML format to extract data
      const parser = new DOMParser()
      const xmlDoc = parser.parseFromString(content, 'text/xml')

      // Check for parsing errors
      const parseError = xmlDoc.querySelector('parsererror')
      if (parseError) {
        return this.extractDataWithRegex(content)
      }

      // Find all rows in the Excel XML
      const rows = xmlDoc.querySelectorAll('Row')

      if (rows.length < 2) {
        return this.extractDataWithRegex(content)
      }

      // Extract headers from first row
      const headerRow = rows[0]
      const headerCells = headerRow.querySelectorAll('Cell Data')
      const headers = Array.from(headerCells).map((cell) => {
        let headerText = cell.textContent?.trim() || ''
        // Fix Turkish character encoding issues in headers
        return this.fixTurkishCharacters(headerText)
      })

      if (headers.length === 0) {
        return this.extractDataWithRegex(content)
      }

      // Extract data from remaining rows
      for (let i = 1; i < rows.length; i++) {
        const row = rows[i]
        const cells = row.querySelectorAll('Cell Data')
        const rowData: any = {}

        cells.forEach((cell, index) => {
          if (index < headers.length && headers[index]) {
            let cellValue = cell.textContent?.trim() || ''

            // Clean up email links - extract just the email address
            if (cellValue.includes('@') && cellValue.includes('mailto:')) {
              const emailMatch = cellValue.match(/mailto:([^"']+)/)
              if (emailMatch) {
                cellValue = emailMatch[1]
              }
            }

            // Fix Turkish character encoding issues
            cellValue = this.fixTurkishCharacters(cellValue)

            rowData[headers[index]] = cellValue
          }
        })

        if (Object.keys(rowData).length > 0) {
          data.push(rowData)
        }
      }

      return data
    } catch (error) {
      console.error('Error extracting Excel data:', error)
      return this.extractDataWithRegex(content)
    }
  }

  private extractDataWithRegex(content: string): any[] {
    try {
      const data: any[] = []

      // Extract all Data elements from Excel XML
      const dataPattern = /<Data\s+ss:Type="String">([^<]+)<\/Data>/g
      const matches = content.match(dataPattern)

      if (!matches || matches.length === 0) {
        return []
      }

      // Extract the actual text content from each match
      const extractedValues = matches
        .map((match) => {
          const valueMatch = match.match(/<Data\s+ss:Type="String">([^<]+)<\/Data>/)
          let value = valueMatch ? valueMatch[1].trim() : ''
          // Fix Turkish character encoding issues
          value = this.fixTurkishCharacters(value)
          return value
        })
        .filter((value) => value)

      // Group values into rows - assuming first row is headers
      if (extractedValues.length >= 4) {
        // At least one header row
        const headers = extractedValues.slice(0, 4) // First 4 values as headers

        // Group remaining values into rows of 4
        const rowSize = headers.length
        for (let i = rowSize; i < extractedValues.length; i += rowSize) {
          const rowValues = extractedValues.slice(i, i + rowSize)
          if (rowValues.length === rowSize) {
            const rowData: any = {}
            headers.forEach((header, index) => {
              rowData[header] = rowValues[index] || ''
            })
            data.push(rowData)
          }
        }
      }

      return data
    } catch (error) {
      console.error('Error in regex extraction:', error)
      return []
    }
  }

  private parseCsvLine(line: string): string[] {
    const result: string[] = []
    let current = ''
    let inQuotes = false

    // Detect delimiter by counting occurrences (prioritize semicolon if it exists)
    const semicolonCount = (line.match(/;/g) || []).length
    const delimiter = semicolonCount > 0 ? ';' : ','

    for (let i = 0; i < line.length; i++) {
      const char = line[i]

      if (char === '"') {
        if (i + 1 < line.length && line[i + 1] === '"') {
          // Handle escaped quotes
          current += '"'
          i++ // Skip next quote
        } else {
          inQuotes = !inQuotes
        }
      } else if (char === delimiter && !inQuotes) {
        result.push(current.trim())
        current = ''
      } else {
        current += char
      }
    }

    result.push(current.trim())
    const cleanedResult = result.map((field) => field.replace(/^"(.*)"$/, '$1'))
    return cleanedResult
  }

  private inferDataType(columnName: string, sampleValue: any): string {
    // Check the column name for common patterns
    const lowerName = columnName.toLowerCase()

    if (lowerName.includes('email')) return 'string'
    if (lowerName.includes('date') || lowerName.includes('time')) return 'date'
    if (
      lowerName.includes('active') ||
      lowerName.includes('enabled') ||
      lowerName.includes('disabled')
    )
      return 'boolean'
    if (lowerName.includes('count') || lowerName.includes('number') || lowerName.includes('amount'))
      return 'number'

    // Check the sample value
    if (sampleValue !== null && sampleValue !== undefined) {
      const strValue = String(sampleValue).toLowerCase().trim()

      // Boolean check
      if (strValue === 'true' || strValue === 'false' || strValue === '1' || strValue === '0') {
        return 'boolean'
      }

      // Number check
      if (!isNaN(Number(strValue)) && strValue !== '') {
        return 'number'
      }

      // Date check (basic patterns)
      if (strValue.match(/^\d{4}-\d{2}-\d{2}/) || strValue.match(/^\d{2}\/\d{2}\/\d{4}/)) {
        return 'date'
      }
    }

    return 'string' // Default to string
  }

  private fixTurkishCharacters(text: string): string {
    return text
  }

  private async tryMultipleEncodings(file: File, encodings: string[]): Promise<string> {
    for (const encoding of encodings) {
      try {
        const content = await this.readFileWithEncoding(file, encoding)
        // Check if the content looks good (no replacement characters)
        if (!content.includes('�') && !content.includes('\ufffd')) {
          return content
        }
      } catch (error) {
        console.log(`Failed to read with encoding ${encoding}:`, error)
      }
    }
    // Fallback to UTF-8 if all else fails
    return this.readFileWithEncoding(file, 'UTF-8')
  }

  private readFileWithEncoding(file: File, encoding: string): Promise<string> {
    return new Promise((resolve, reject) => {
      const reader = new FileReader()
      reader.onload = (e) => resolve(e.target?.result as string)
      reader.onerror = reject
      reader.readAsText(file, encoding)
    })
  }
}