import { execFile } from 'child_process';
import { promisify } from 'util';
import path from 'path';
import fs from 'fs';
import { ToolResult } from '../types.js';
import { getWorkspacePath } from '../config/paths.js';

const execFileAsync = promisify(execFile);

// ─── Python scripts ────────────────────────────────────────────────────────────

const READ_SCRIPT = `
import sys, json
try:
    import openpyxl
except ImportError:
    print(json.dumps({"error": "openpyxl_missing"}))
    sys.exit(1)

xlsx_path  = sys.argv[1]
sheet_name = sys.argv[2] if len(sys.argv) > 2 and sys.argv[2] != '__ALL__' else None
cell_range = sys.argv[3] if len(sys.argv) > 3 and sys.argv[3] != '__NONE__' else None
max_rows   = int(sys.argv[4]) if len(sys.argv) > 4 else 500

wb = openpyxl.load_workbook(xlsx_path, read_only=True, data_only=True)
sheet_names = wb.sheetnames

if sheet_name is None:
    # Return sheet list + preview of first sheet
    ws = wb.active
    target_sheets = [ws.title]
else:
    if sheet_name not in sheet_names:
        print(json.dumps({"error": f"Sheet '{sheet_name}' not found. Available: {sheet_names}"}))
        sys.exit(1)
    ws = wb[sheet_name]
    target_sheets = [sheet_name]

results = []
for sname in target_sheets:
    ws = wb[sname]

    if cell_range:
        cells = ws[cell_range]
        if not hasattr(cells, '__iter__') or isinstance(cells, openpyxl.cell.cell.Cell):
            cells = [[cells]]
        elif not hasattr(cells[0], '__iter__'):
            cells = [cells]
        rows = [[str(c.value) if c.value is not None else '' for c in row] for row in cells]
    else:
        rows = []
        for i, row in enumerate(ws.iter_rows(values_only=True)):
            if i >= max_rows:
                rows.append([f'... ({ws.max_row - max_rows} more rows truncated)'])
                break
            rows.append([str(v) if v is not None else '' for v in row])

    # Strip trailing empty rows
    while rows and all(c == '' for c in rows[-1]):
        rows.pop()

    results.append({"sheet": sname, "rows": rows, "total_rows": ws.max_row, "total_cols": ws.max_column})

print(json.dumps({"sheets": sheet_names, "data": results}))
`;

const WRITE_SCRIPT = `
import sys, json, os
try:
    import openpyxl
    from openpyxl.styles import Font, PatternFill, Alignment
except ImportError:
    print(json.dumps({"error": "openpyxl_missing"}))
    sys.exit(1)

spec_path = sys.argv[1]
with open(spec_path) as f:
    spec = json.load(f)

xlsx_path  = spec['path']
sheet_name = spec.get('sheet', 'Sheet1')
data       = spec.get('data', [])
headers    = spec.get('headers', [])
start_cell = spec.get('start_cell', 'A1')
mode       = spec.get('mode', 'create')  # create | append | overwrite_sheet

# Load or create workbook
if mode != 'create' and os.path.exists(xlsx_path):
    wb = openpyxl.load_workbook(xlsx_path)
    if sheet_name in wb.sheetnames:
        if mode == 'overwrite_sheet':
            del wb[sheet_name]
            ws = wb.create_sheet(sheet_name)
        else:
            ws = wb[sheet_name]
            # append: find last row
            start_cell = f'A{ws.max_row + 1}'
    else:
        ws = wb.create_sheet(sheet_name)
else:
    wb = openpyxl.Workbook()
    ws = wb.active
    ws.title = sheet_name

# Parse start cell
import re
m = re.match(r'([A-Za-z]+)([0-9]+)', start_cell)
col_letter = m.group(1).upper() if m else 'A'
start_row  = int(m.group(2)) if m else 1
start_col  = openpyxl.utils.column_index_from_string(col_letter)

# Write headers
row_offset = 0
if headers:
    for ci, h in enumerate(headers):
        cell = ws.cell(row=start_row, column=start_col + ci, value=h)
        cell.font = Font(bold=True)
        cell.fill = PatternFill('solid', fgColor='D9E1F2')
    row_offset = 1

# Write data
for ri, row in enumerate(data):
    for ci, val in enumerate(row):
        ws.cell(row=start_row + row_offset + ri, column=start_col + ci, value=val)

# Auto-fit column widths (approximate)
for col in ws.columns:
    max_len = 0
    col_letter2 = openpyxl.utils.get_column_letter(col[0].column)
    for cell in col:
        try:
            if cell.value:
                max_len = max(max_len, len(str(cell.value)))
        except:
            pass
    ws.column_dimensions[col_letter2].width = min(max(max_len + 2, 8), 50)

os.makedirs(os.path.dirname(os.path.abspath(xlsx_path)), exist_ok=True)
wb.save(xlsx_path)
rel = os.path.relpath(xlsx_path)
print(json.dumps({"success": True, "path": xlsx_path, "sheet": sheet_name, "rows_written": len(data)}))
`;

// ─── Helpers ──────────────────────────────────────────────────────────────────

function formatTable(rows: string[][]): string {
  if (rows.length === 0) return '(empty)';
  const widths = rows[0].map((_, ci) =>
    Math.min(40, Math.max(...rows.map(r => (r[ci] ?? '').length)))
  );
  return rows
    .map(row => row.map((cell, ci) => (cell ?? '').padEnd(widths[ci])).join('  '))
    .join('\n');
}

// ─── Tools ────────────────────────────────────────────────────────────────────

export const excelReadTool = {
  name: 'excel_read',
  description: 'Read data from an Excel (.xlsx) file. Returns sheet names, row data as a formatted table. Supports reading a specific sheet, cell range, and row limit.',
  schema: {
    path:      'Path to the .xlsx file (absolute or relative to workspace)',
    sheet:     'Sheet name to read (default: active/first sheet)',
    range:     'Cell range to read, e.g. "A1:F20" (default: entire sheet)',
    max_rows:  'Maximum rows to return (default: 500)',
  },
  jsonSchema: {
    type: 'object',
    properties: {
      path:     { type: 'string',  description: 'Path to .xlsx file' },
      sheet:    { type: 'string',  description: 'Sheet name (default: first sheet)' },
      range:    { type: 'string',  description: 'Cell range e.g. "A1:F20"' },
      max_rows: { type: 'number',  description: 'Max rows to return (default: 500)' },
    },
    required: ['path'],
    additionalProperties: false,
  },
  execute: async (args: any): Promise<ToolResult> => {
    const filePath = String(args?.path || '').trim();
    if (!filePath) return { success: false, error: 'path is required' };

    const workspacePath = getWorkspacePath(args);
    const resolved = path.isAbsolute(filePath) ? filePath : path.resolve(workspacePath, filePath);

    if (!fs.existsSync(resolved)) {
      return { success: false, error: `File not found: ${resolved}` };
    }
    const ext = path.extname(resolved).toLowerCase();
    if (ext !== '.xlsx') {
      return { success: false, error: 'Only .xlsx files are supported (not .xls or .csv)' };
    }

    const sheetArg  = args?.sheet  ? String(args.sheet)  : '__ALL__';
    const rangeArg  = args?.range  ? String(args.range)  : '__NONE__';
    const maxRows   = args?.max_rows ? Math.min(5000, Math.max(1, Number(args.max_rows))) : 500;

    let result: any;
    try {
      const { stdout } = await execFileAsync(
        'python3', ['-c', READ_SCRIPT, resolved, sheetArg, rangeArg, String(maxRows)],
        { maxBuffer: 20 * 1024 * 1024, timeout: 30_000 }
      );
      result = JSON.parse(stdout.trim());
    } catch (err: any) {
      return { success: false, error: `excel_read failed: ${err.message}` };
    }

    if (result.error) {
      if (result.error === 'openpyxl_missing') {
        return { success: false, error: 'openpyxl not installed. Run: pip3 install openpyxl' };
      }
      return { success: false, error: result.error };
    }

    const lines: string[] = [`Sheets: ${result.sheets.join(', ')}\n`];
    for (const block of result.data) {
      lines.push(`=== Sheet: ${block.sheet} (${block.total_rows} rows × ${block.total_cols} cols) ===`);
      lines.push(formatTable(block.rows));
    }

    return {
      success: true,
      stdout: lines.join('\n'),
      data: { sheets: result.sheets, sheetCount: result.sheets.length },
    };
  },
};

export const excelWriteTool = {
  name: 'excel_write',
  description: 'Create or update an Excel (.xlsx) file. Writes data rows with optional bold headers. Supports creating new files, appending rows, or overwriting a specific sheet.',
  schema: {
    path:        'Output path for .xlsx file (absolute or relative to workspace)',
    sheet:       'Sheet name (default: "Sheet1")',
    headers:     'Array of column header strings (written in bold)',
    data:        'Array of rows, each row is an array of values',
    start_cell:  'Top-left cell to start writing, e.g. "A1" (default: "A1")',
    mode:        'create | append | overwrite_sheet (default: create)',
  },
  jsonSchema: {
    type: 'object',
    properties: {
      path:       { type: 'string',  description: 'Output .xlsx path' },
      sheet:      { type: 'string',  description: 'Sheet name (default: Sheet1)' },
      headers:    { type: 'array',   items: { type: 'string' }, description: 'Column headers (bold)' },
      data:       { type: 'array',   items: { type: 'array' }, description: 'Rows of data (array of arrays)' },
      start_cell: { type: 'string',  description: 'Start cell e.g. "A1"' },
      mode:       { type: 'string',  enum: ['create', 'append', 'overwrite_sheet'], description: 'Write mode' },
    },
    required: ['path', 'data'],
    additionalProperties: false,
  },
  execute: async (args: any): Promise<ToolResult> => {
    const filePath = String(args?.path || '').trim();
    if (!filePath) return { success: false, error: 'path is required' };
    if (!Array.isArray(args?.data)) return { success: false, error: 'data must be an array of rows' };

    const workspacePath = getWorkspacePath(args);
    const resolved = path.isAbsolute(filePath) ? filePath : path.resolve(workspacePath, filePath);

    if (path.extname(resolved).toLowerCase() !== '.xlsx') {
      return { success: false, error: 'Output file must have .xlsx extension' };
    }

    const spec = {
      path:       resolved,
      sheet:      args?.sheet      || 'Sheet1',
      headers:    args?.headers    || [],
      data:       args?.data       || [],
      start_cell: args?.start_cell || 'A1',
      mode:       args?.mode       || 'create',
    };

    const tmpSpec = resolved + `.spec_${Date.now()}.json`;
    try {
      fs.writeFileSync(tmpSpec, JSON.stringify(spec), 'utf-8');
      const { stdout } = await execFileAsync(
        'python3', ['-c', WRITE_SCRIPT, tmpSpec],
        { maxBuffer: 5 * 1024 * 1024, timeout: 30_000 }
      );
      const result = JSON.parse(stdout.trim());
      if (result.error) {
        if (result.error === 'openpyxl_missing') {
          return { success: false, error: 'openpyxl not installed. Run: pip3 install openpyxl' };
        }
        return { success: false, error: result.error };
      }
      const filename = path.basename(resolved);
      const rel = path.relative(workspacePath, resolved);
      return {
        success: true,
        stdout: `Excel file saved: ${filename} | Sheet: ${result.sheet} | Rows written: ${result.rows_written}`,
        data: { path: resolved, filename, sheet: result.sheet, rowsWritten: result.rows_written },
      };
    } catch (err: any) {
      return { success: false, error: `excel_write failed: ${err.message}` };
    } finally {
      try { fs.unlinkSync(tmpSpec); } catch {}
    }
  },
};