import html
from pathlib import Path
from urllib.parse import quote

from fastapi import APIRouter, Depends, Form, HTTPException, Request
from fastapi.responses import FileResponse, HTMLResponse, RedirectResponse

from ..auth import require_user
from ..backups import backup_dir, is_backup_path, list_backups
from ..config import BACKUP_SCRIPT, RESTORE_SCRIPT
from ..db.audit import log_audit_event
from ..shell import run_command
from ..templates.layout import page, render_result

router = APIRouter()


def is_admin(user) -> bool:
    return (user.get("role") or "").lower() == "admin"


@router.get("/backups", response_class=HTMLResponse)
def backups_page(request: Request, user=Depends(require_user)):
    rows = ""
    can_download = is_admin(user)

    for path in list_backups():
        size_mb = path.stat().st_size / 1024 / 1024
        backup_name = html.escape(path.name)
        backup_path = html.escape(str(path), quote=True)
        backup_url_name = quote(path.name, safe="")
        download_action = (
            f'<a class="btn btn-secondary" href="/portal/backups/download/{backup_url_name}">'
            f'<i class="fa-solid fa-download" aria-hidden="true"></i> Stáhnout</a>'
            if can_download
            else ""
        )
        # Restore overwrites live data, so it is admin-only and guarded by an explicit confirm.
        restore_action = (
            f"""
                <form method="post" action="/portal/backups/restore"
                      onsubmit="return confirm('Obnovit zálohu {backup_name}?\\n\\nTato akce přepíše aktuální data AppFactory a může restartovat běžící služby. Akce je nevratná.');">
                    <input type="hidden" name="backup_path" value="{backup_path}">
                    <button type="submit" class="btn btn-secondary">
                        <i class="fa-solid fa-clock-rotate-left" aria-hidden="true"></i> Obnovit
                    </button>
                </form>
            """
            if can_download
            else ""
        )

        rows += f"""
        <tr class="backup-row">
            <td>
                <strong>{backup_name}</strong><br>
                <span class="muted">{size_mb:.2f} MB</span>
            </td>
            <td>
                <div class="copy-row">
                    <input readonly value="{backup_path}">
                    <button type="button" class="copy-button" data-copy-value="{backup_path}" onclick="copyText(this)">
                        <i class="fa-solid fa-copy" aria-hidden="true"></i> Kopírovat
                    </button>
                </div>
            </td>
            <td class="actions-cell">
                {download_action}
                {restore_action}
                <form method="post" action="/portal/backups/delete" onsubmit="return confirm('Smazat zálohu {backup_name}?');">
                    <input type="hidden" name="backup_path" value="{backup_path}">
                    <button type="submit" class="danger">
                        <i class="fa-solid fa-trash" aria-hidden="true"></i> Smazat
                    </button>
                </form>
            </td>
        </tr>
        """

    if not rows:
        rows = '<tr><td colspan="3">Nebyly nalezeny žádné zálohy.</td></tr>'

    restore_hint = (
        "Obnovu lze spustit přímo z portálu tlačítkem Obnovit (pouze administrátor)."
        if can_download
        else "Obnovu zálohy může spustit pouze administrátor."
    )

    return page(
        "Zálohy",
        f"""
        <div class="card">
            <h2><i class="fa-solid fa-box-archive" aria-hidden="true"></i> Správa záloh</h2>
            <p class="muted">
                Zálohy neobsahují samotný adresář se zálohami.
                Obnova starší zálohy by neměla smazat novější soubory .tar.gz.
                {restore_hint} Obnova přepíše aktuální data a je nevratná.
            </p>

            <form method="post" action="/portal/backups/create">
                <button type="submit"><i class="fa-solid fa-plus" aria-hidden="true"></i> Vytvořit zálohu</button>
            </form>
        </div>

        <div class="card">
            <h2>Dostupné zálohy</h2>
            <table>
                <tr>
                    <th>Záloha</th>
                    <th>Cesta</th>
                    <th>Akce</th>
                </tr>
                {rows}
            </table>
        </div>
        """,
        user=user,
    )


@router.get("/backups/download/{backup_name}")
def download_backup(backup_name: str, user=Depends(require_user)):
    if not is_admin(user):
        raise HTTPException(status_code=403, detail="Only admins can download backups")

    target = backup_dir() / backup_name
    if not is_backup_path(target):
        raise HTTPException(status_code=400, detail="Invalid backup path")

    target = target.resolve()
    if not target.exists() or not target.is_file():
        raise HTTPException(status_code=404, detail="Backup not found")

    log_audit_event(
        user,
        action="backup_download",
        target_type="backup",
        target_id=target.name,
        metadata={"backup_path": str(target)},
    )

    return FileResponse(
        path=target,
        filename=target.name,
        media_type="application/gzip",
    )


@router.post("/backups/create", response_class=HTMLResponse)
def create_backup(user=Depends(require_user)):
    result = run_command([BACKUP_SCRIPT])
    status = "OK" if result.returncode == 0 else "FAILED"
    log_audit_event(
        user,
        action="backup_create",
        target_type="backup",
        metadata={
            "status": status,
            "returncode": result.returncode,
        },
    )

    return render_result(
        title=f"Vytvoření zálohy: {status}",
        back_url="/portal/backups",
        sections=[("Výstup", result.stdout), ("Chyba", result.stderr)],
        user=user,
    )


@router.post("/backups/delete")
def delete_backup(backup_path: str = Form(...), user=Depends(require_user)):
    target = Path(backup_path)

    if not is_backup_path(target):
        return HTMLResponse("Neplatná cesta k záloze", status_code=400)

    target = target.resolve()
    if target.exists():
        target.unlink()

    return RedirectResponse(url="/portal/backups", status_code=303)


@router.post("/backups/restore", response_class=HTMLResponse)
def restore_backup(backup_path: str = Form(...), user=Depends(require_user)):
    # Restoring overwrites live data and may restart services, so it is restricted to admins.
    if not is_admin(user):
        raise HTTPException(status_code=403, detail="Only admins can restore backups")

    target = Path(backup_path)
    if not is_backup_path(target):
        return HTMLResponse("Neplatná cesta k záloze", status_code=400)

    target = target.resolve()
    if not target.exists() or not target.is_file():
        raise HTTPException(status_code=404, detail="Backup not found")

    result = run_command([RESTORE_SCRIPT, "--force", str(target)])
    status = "OK" if result.returncode == 0 else "FAILED"

    log_audit_event(
        user,
        action="backup_restore",
        target_type="backup",
        target_id=target.name,
        metadata={
            "backup_path": str(target),
            "status": status,
            "returncode": result.returncode,
        },
    )

    return render_result(
        title=f"Obnova zálohy: {status}",
        back_url="/portal/backups",
        sections=[("Výstup", result.stdout), ("Chyba", result.stderr)],
        user=user,
    )