"""Engagement export renderers — Markdown, CSV, PDF."""
from __future__ import annotations

import csv
import io
import re
import unicodedata
from datetime import date
from html import escape as _html_escape
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from backend.app.models.engagement import Engagement
    from backend.app.models.simulation import Simulation


def _export_filename(engagement: Engagement, ext: str) -> str:
    name = engagement.name or ""
    normalized = unicodedata.normalize("NFKD", name).encode("ascii", "ignore").decode()
    slug = re.sub(r"[^a-z0-9]+", "-", normalized.lower()).strip("-")[:60] or "unnamed"
    today = date.today().strftime("%Y%m%d")
    return f"engagement-{engagement.id}-{slug}-{today}.{ext}"


def _tactic_names(tactic_ids: list[str]) -> str:
    from backend.app.serializers import _enrich_tactics

    enriched = _enrich_tactics(tactic_ids or [])
    return " | ".join(e.get("name", e.get("id", "")) for e in enriched)


def _enrich_sim_techniques(techniques: list[dict]) -> list[dict]:
    from backend.app.serializers import _enrich_techniques

    return _enrich_techniques(techniques or [])


def _creator(obj: object) -> str:
    """Return username string from an ORM object with a created_by relationship."""
    cb = getattr(obj, "created_by", None)
    if cb is None:
        return ""
    return getattr(cb, "username", "") or ""


# ---------------------------------------------------------------------------
# Markdown
# ---------------------------------------------------------------------------


def render_engagement_markdown(
    engagement: Engagement, simulations: list[Simulation]
) -> str:
    lines: list[str] = []

    lines.append(f"# {engagement.name}")
    lines.append("")
    if engagement.description:
        lines.append(engagement.description)
        lines.append("")
    lines.append(f"**Status**: {engagement.status.value}")
    lines.append(
        f"**Start date**: {engagement.start_date.isoformat() if engagement.start_date else 'N/A'}"
    )
    lines.append(
        f"**End date**: {engagement.end_date.isoformat() if engagement.end_date else 'N/A'}"
    )
    lines.append(
        f"**Created by**: {_creator(engagement)}"
    )
    lines.append(
        f"**Created at**: {engagement.created_at.isoformat() if engagement.created_at else 'N/A'}"
    )
    lines.append("")

    if not simulations:
        return "\n".join(lines)

    lines.append("---")
    lines.append("")
    lines.append("## Simulations")
    lines.append("")

    for sim in simulations:
        enriched_techniques = _enrich_sim_techniques(sim.techniques)
        tech_str = " | ".join(
            f"{t['id']} — {t['name']}" for t in enriched_techniques
        ) if enriched_techniques else "N/A"
        tactic_str = _tactic_names(sim.tactic_ids) or "N/A"

        lines.append(f"### {sim.name}")
        lines.append("")
        lines.append(f"**Status**: {sim.status.value}")
        lines.append(f"**Techniques**: {tech_str}")
        lines.append(f"**Tactics**: {tactic_str}")
        if sim.description:
            lines.append(f"**Description**: {sim.description}")
        lines.append(
            f"**Executed at**: {sim.executed_at.isoformat() if sim.executed_at else 'N/A'}"
        )
        lines.append(f"**Execution result**: {sim.execution_result or 'N/A'}")
        lines.append("")

        lines.append("**Commands**:")
        if sim.commands:
            safe = sim.commands.replace("~~~", "\\~\\~\\~")
            lines.append("~~~bash")
            lines.append(safe)
            lines.append("~~~")
        else:
            lines.append("N/A")
        lines.append("")

        lines.append(f"**Prerequisites**: {sim.prerequisites or 'N/A'}")
        lines.append("")

        lines.append("#### SOC")
        lines.append(f"**Log source**: {sim.log_source or 'N/A'}")
        lines.append(f"**Logs**: {sim.logs or 'N/A'}")
        lines.append(f"**SOC comment**: {sim.soc_comment or 'N/A'}")
        lines.append(f"**Incident number**: {sim.incident_number or 'N/A'}")
        lines.append("")

    return "\n".join(lines)


# ---------------------------------------------------------------------------
# CSV
# ---------------------------------------------------------------------------

_CSV_HEADERS = [
    "id",
    "name",
    "status",
    "techniques",
    "tactics",
    "description",
    "commands",
    "prerequisites",
    "executed_at",
    "execution_result",
    "log_source",
    "logs",
    "soc_comment",
    "incident_number",
    "created_at",
    "updated_at",
]

# \t and \r included: Excel auto-trims leading whitespace, so a tab/CR prefix still
# reaches the formula parser in some sheet versions.
_CSV_FORMULA_TRIGGERS = ("=", "+", "-", "@", "\t", "\r")


def _csv_safe(value: object) -> object:
    """Defuse spreadsheet formula injection by prefixing user-controlled cells.

    Excel / LibreOffice / Google Sheets interpret cells starting with =, +, -, @,
    \\t or \\r as formulas. Since this CSV is the engagement handoff to SOC and is
    explicitly opened in a spreadsheet app, an authenticated red-team user could
    craft a simulation field that executes on the SOC analyst's machine. Prefixing
    with a single apostrophe forces the spreadsheet to treat the cell as text.
    """
    if isinstance(value, str) and value and value[0] in _CSV_FORMULA_TRIGGERS:
        return "'" + value
    return value


def render_engagement_csv(
    _engagement: Engagement, simulations: list[Simulation]
) -> str:
    buf = io.StringIO()
    writer = csv.writer(buf)
    writer.writerow(_CSV_HEADERS)

    for sim in simulations:
        enriched_techniques = _enrich_sim_techniques(sim.techniques)
        tech_ids = "|".join(t["id"] for t in enriched_techniques)
        tactic_str = "|".join(sim.tactic_ids or [])

        writer.writerow([
            sim.id,
            _csv_safe(sim.name),
            sim.status.value,
            _csv_safe(tech_ids),
            _csv_safe(tactic_str),
            _csv_safe(sim.description or ""),
            _csv_safe(sim.commands or ""),
            _csv_safe(sim.prerequisites or ""),
            sim.executed_at.isoformat() if sim.executed_at else "",
            _csv_safe(sim.execution_result or ""),
            _csv_safe(sim.log_source or ""),
            _csv_safe(sim.logs or ""),
            _csv_safe(sim.soc_comment or ""),
            _csv_safe(sim.incident_number or ""),
            sim.created_at.isoformat() if sim.created_at else "",
            sim.updated_at.isoformat() if sim.updated_at else "",
        ])

    return buf.getvalue()


# ---------------------------------------------------------------------------
# HTML (internal, used by PDF renderer)
# ---------------------------------------------------------------------------

_CSS = """
body { font-family: sans-serif; font-size: 13px; color: #1a1a1a; margin: 40px; }
h1 { font-size: 22px; border-bottom: 2px solid #333; padding-bottom: 6px; }
h2 { font-size: 17px; margin-top: 32px; color: #333; }
h3 { font-size: 14px; margin-top: 24px; background: #f0f0f0; padding: 4px 8px; }
h3:nth-of-type(odd) { background: #e8e8e8; }
table { border-collapse: collapse; width: 100%; margin-bottom: 12px; }
th, td { border: 1px solid #ccc; padding: 4px 8px; text-align: left; vertical-align: top; }
th { background: #e0e0e0; }
pre { background: #f5f5f5; padding: 8px; font-size: 11px; white-space: pre-wrap; word-break: break-all; }
.meta { color: #555; margin-bottom: 16px; }
"""


def _render_engagement_html(
    engagement: Engagement, simulations: list[Simulation]
) -> str:
    h = _html_escape
    parts: list[str] = []

    parts.append("<!DOCTYPE html><html><head><meta charset='utf-8'>")
    parts.append(f"<style>{_CSS}</style></head><body>")
    parts.append(f"<h1>{h(engagement.name)}</h1>")
    parts.append("<div class='meta'>")
    if engagement.description:
        parts.append(f"<p>{h(engagement.description)}</p>")
    parts.append(f"<p><strong>Status:</strong> {h(engagement.status.value)}</p>")
    sd = engagement.start_date.isoformat() if engagement.start_date else "N/A"
    ed = engagement.end_date.isoformat() if engagement.end_date else "N/A"
    parts.append(f"<p><strong>Dates:</strong> {h(sd)} → {h(ed)}</p>")
    parts.append(f"<p><strong>Created by:</strong> {h(_creator(engagement))}</p>")
    ca = engagement.created_at.isoformat() if engagement.created_at else "N/A"
    parts.append(f"<p><strong>Created at:</strong> {h(ca)}</p>")
    parts.append("</div>")

    if simulations:
        parts.append("<h2>Simulations</h2>")
        for sim in simulations:
            enriched_techniques = _enrich_sim_techniques(sim.techniques)
            tech_str = h(
                " | ".join(f"{t['id']} — {t['name']}" for t in enriched_techniques)
                or "N/A"
            )
            tactic_str = h(_tactic_names(sim.tactic_ids) or "N/A")

            parts.append(f"<h3>{h(sim.name)}</h3>")
            parts.append("<table>")
            parts.append(f"<tr><th>Status</th><td>{h(sim.status.value)}</td></tr>")
            parts.append(f"<tr><th>Techniques</th><td>{tech_str}</td></tr>")
            parts.append(f"<tr><th>Tactics</th><td>{tactic_str}</td></tr>")
            parts.append(
                f"<tr><th>Description</th><td>{h(sim.description or '')}</td></tr>"
            )
            executed = sim.executed_at.isoformat() if sim.executed_at else "N/A"
            parts.append(f"<tr><th>Executed at</th><td>{h(executed)}</td></tr>")
            parts.append(
                f"<tr><th>Execution result</th><td>{h(sim.execution_result or '')}</td></tr>"
            )
            parts.append("</table>")

            if sim.commands:
                parts.append(f"<p><strong>Commands:</strong></p><pre>{h(sim.commands)}</pre>")

            if sim.prerequisites:
                parts.append(
                    f"<p><strong>Prerequisites:</strong> {h(sim.prerequisites)}</p>"
                )

            parts.append("<table>")
            parts.append("<tr><th colspan='2'>SOC</th></tr>")
            parts.append(
                f"<tr><th>Log source</th><td>{h(sim.log_source or '')}</td></tr>"
            )
            parts.append(f"<tr><th>Logs</th><td>{h(sim.logs or '')}</td></tr>")
            parts.append(
                f"<tr><th>SOC comment</th><td>{h(sim.soc_comment or '')}</td></tr>"
            )
            parts.append(
                f"<tr><th>Incident number</th><td>{h(sim.incident_number or '')}</td></tr>"
            )
            parts.append("</table>")

    parts.append("</body></html>")
    return "".join(parts)


# ---------------------------------------------------------------------------
# PDF
# ---------------------------------------------------------------------------


def render_engagement_pdf(
    engagement: Engagement, simulations: list[Simulation]
) -> bytes:
    from weasyprint import HTML

    html = _render_engagement_html(engagement, simulations)
    return HTML(string=html).write_pdf()