"""
Generate an XLSX audit report with four sheets:

  1. Summary        – score, counts, target info
  2. Passed         – checks that passed, actual vs expected
  3. Failed         – checks that failed, actual vs expected, remediation
  4. Manual Review  – checks requiring human judgment, command output + criteria
  5. Errors         – checks that could not run

Uses openpyxl (bundled with most Python environments).
"""
from __future__ import annotations

from datetime import datetime
from pathlib import Path
from typing import List

import openpyxl
from openpyxl.styles import (
    Alignment, Font, PatternFill, Border, Side
)
from openpyxl.utils import get_column_letter

from .models import AuditReport, CheckResult, PASS, FAIL, MANUAL, ERROR


# ── colour palette ────────────────────────────────────────────────────────────
C_HEADER_BG  = "1F4E79"   # dark blue  – header row
C_HEADER_FG  = "FFFFFF"   # white
C_PASS_BG    = "E2EFDA"   # light green
C_FAIL_BG    = "FCE4D6"   # light red/orange
C_MANUAL_BG  = "FFF2CC"   # light yellow
C_ERROR_BG   = "F2CEEF"   # light purple
C_ALT_BG     = "F5F5F5"   # very light grey – alternating rows
C_SUMMARY_BG = "DEEAF1"   # light blue – summary labels

# thin border
_THIN = Side(style="thin", color="BFBFBF")
_BORDER = Border(left=_THIN, right=_THIN, top=_THIN, bottom=_THIN)


# ── helpers ───────────────────────────────────────────────────────────────────

def _header_font() -> Font:
    return Font(name="Calibri", bold=True, color=C_HEADER_FG, size=11)


def _bold(color: str = "000000") -> Font:
    return Font(name="Calibri", bold=True, color=color, size=11)


def _normal(size: int = 11) -> Font:
    return Font(name="Calibri", size=size)


def _fill(hex_color: str) -> PatternFill:
    return PatternFill("solid", fgColor=hex_color)


def _wrap_align() -> Alignment:
    return Alignment(wrap_text=True, vertical="top")


def _set_header_row(ws, headers: list[str], row: int = 1) -> None:
    for col, title in enumerate(headers, 1):
        cell = ws.cell(row=row, column=col, value=title)
        cell.font = _header_font()
        cell.fill = _fill(C_HEADER_BG)
        cell.alignment = Alignment(wrap_text=True, vertical="center", horizontal="center")
        cell.border = _BORDER


def _write_row(ws, row: int, values: list, bg_color: str | None = None) -> None:
    for col, val in enumerate(values, 1):
        cell = ws.cell(row=row, column=col, value=str(val) if val is not None else "")
        cell.font = _normal()
        cell.alignment = _wrap_align()
        cell.border = _BORDER
        if bg_color:
            cell.fill = _fill(bg_color)
        elif row % 2 == 0:
            cell.fill = _fill(C_ALT_BG)


def _auto_width(ws, min_w: int = 12, max_w: int = 60) -> None:
    for col_cells in ws.columns:
        length = max(
            len(str(cell.value or "")) for cell in col_cells
        )
        col_letter = get_column_letter(col_cells[0].column)
        ws.column_dimensions[col_letter].width = max(min_w, min(length + 2, max_w))


def _freeze(ws, cell: str = "A2") -> None:
    ws.freeze_panes = cell


# ── sheet builders ────────────────────────────────────────────────────────────

def _build_summary(wb: openpyxl.Workbook, report: AuditReport) -> None:
    ws = wb.active
    ws.title = "Summary"
    ws.sheet_view.showGridLines = False

    rows = [
        ("CIS NGINX Benchmark v3.0.0 – Audit Report", ""),
        ("", ""),
        ("Target",    report.target),
        ("Profile",   report.profile),
        ("Timestamp", report.timestamp.strftime("%Y-%m-%d %H:%M:%S UTC")),
        ("", ""),
        ("Total Checks",   report.total),
        ("✅ PASS",        len(report.passed)),
        ("❌ FAIL",        len(report.failed)),
        ("⚠️  MANUAL",     len(report.manual)),
        ("🔴 ERROR",       len(report.errors)),
        ("", ""),
    ]

    if report.total:
        pct_pass = round(len(report.passed) / report.total * 100, 1)
        pct_fail = round(len(report.failed) / report.total * 100, 1)
        rows.append(("Pass Rate",  f"{pct_pass}%"))
        rows.append(("Fail Rate",  f"{pct_fail}%"))

    for r_idx, (label, value) in enumerate(rows, 1):
        if r_idx == 1:
            cell = ws.cell(row=r_idx, column=1, value=label)
            cell.font = Font(name="Calibri", bold=True, size=16, color=C_HEADER_BG)
            cell.alignment = Alignment(vertical="center")
            ws.row_dimensions[r_idx].height = 30
            ws.merge_cells(start_row=r_idx, start_column=1, end_row=r_idx, end_column=2)
        else:
            lbl_cell = ws.cell(row=r_idx, column=1, value=label)
            val_cell = ws.cell(row=r_idx, column=2, value=value)
            if label and label not in ("",):
                lbl_cell.font = _bold(C_HEADER_BG)
                lbl_cell.fill = _fill(C_SUMMARY_BG)
                val_cell.font = _normal()

    ws.column_dimensions["A"].width = 22
    ws.column_dimensions["B"].width = 40


def _build_passed(wb: openpyxl.Workbook, results: list[CheckResult]) -> None:
    ws = wb.create_sheet("Passed")
    ws.sheet_view.showGridLines = False
    headers = ["Check ID", "Title", "Commands Run", "Actual Value", "Expected Value"]
    _set_header_row(ws, headers)

    for r_idx, res in enumerate(results, 2):
        _write_row(ws, r_idx, [
            res.check_id,
            res.title,
            "\n".join(res.commands_run),
            res.actual_value,
            res.expected_value,
        ], bg_color=C_PASS_BG)
        ws.row_dimensions[r_idx].height = max(
            30, min(len(res.actual_value) // 3, 120)
        )

    _auto_width(ws)
    _freeze(ws)
    ws.column_dimensions["A"].width = 12
    ws.column_dimensions["B"].width = 52
    ws.column_dimensions["C"].width = 55
    ws.column_dimensions["D"].width = 55
    ws.column_dimensions["E"].width = 45


def _build_failed(wb: openpyxl.Workbook, results: list[CheckResult]) -> None:
    ws = wb.create_sheet("Failed")
    ws.sheet_view.showGridLines = False
    headers = [
        "Check ID", "Title", "Commands Run",
        "Actual Value", "Expected Value", "Remediation Steps", "Notes"
    ]
    _set_header_row(ws, headers)

    for r_idx, res in enumerate(results, 2):
        _write_row(ws, r_idx, [
            res.check_id,
            res.title,
            "\n".join(res.commands_run),
            res.actual_value,
            res.expected_value,
            res.remediation,
            res.notes,
        ], bg_color=C_FAIL_BG)
        ws.row_dimensions[r_idx].height = max(
            30, min(max(len(res.actual_value), len(res.remediation)) // 3, 150)
        )

    _auto_width(ws)
    _freeze(ws)
    ws.column_dimensions["A"].width = 12
    ws.column_dimensions["B"].width = 52
    ws.column_dimensions["C"].width = 55
    ws.column_dimensions["D"].width = 55
    ws.column_dimensions["E"].width = 45
    ws.column_dimensions["F"].width = 60
    ws.column_dimensions["G"].width = 40


def _build_manual(wb: openpyxl.Workbook, results: list[CheckResult]) -> None:
    ws = wb.create_sheet("Manual Review")
    ws.sheet_view.showGridLines = False
    headers = [
        "Check ID", "Title", "Commands Run",
        "Command Output (Actual)", "What to Look For (Expected)", "Notes"
    ]
    _set_header_row(ws, headers)

    for r_idx, res in enumerate(results, 2):
        _write_row(ws, r_idx, [
            res.check_id,
            res.title,
            "\n".join(res.commands_run),
            res.actual_value,
            res.expected_value,
            res.notes,
        ], bg_color=C_MANUAL_BG)
        ws.row_dimensions[r_idx].height = max(
            30, min(len(res.actual_value) // 3, 150)
        )

    _auto_width(ws)
    _freeze(ws)
    ws.column_dimensions["A"].width = 12
    ws.column_dimensions["B"].width = 52
    ws.column_dimensions["C"].width = 55
    ws.column_dimensions["D"].width = 60
    ws.column_dimensions["E"].width = 55
    ws.column_dimensions["F"].width = 40


def _build_errors(wb: openpyxl.Workbook, results: list[CheckResult]) -> None:
    if not results:
        return
    ws = wb.create_sheet("Errors")
    ws.sheet_view.showGridLines = False
    headers = ["Check ID", "Title", "Commands Run", "Error Detail", "Notes"]
    _set_header_row(ws, headers)

    for r_idx, res in enumerate(results, 2):
        _write_row(ws, r_idx, [
            res.check_id,
            res.title,
            "\n".join(res.commands_run),
            res.actual_value,
            res.notes,
        ], bg_color=C_ERROR_BG)

    _auto_width(ws)
    _freeze(ws)


# ── public API ────────────────────────────────────────────────────────────────

def generate_report(report: AuditReport, output_path: str | Path) -> Path:
    """
    Write the audit report as an XLSX file to *output_path*.
    Returns the resolved Path.
    """
    wb = openpyxl.Workbook()

    _build_summary(wb, report)
    _build_passed(wb, report.passed)
    _build_failed(wb, report.failed)
    _build_manual(wb, report.manual)
    _build_errors(wb, report.errors)

    path = Path(output_path)
    path.parent.mkdir(parents=True, exist_ok=True)
    wb.save(path)
    return path