import html
from urllib.parse import quote

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

from app.auth import require_user
from app.db.audit import log_audit_event
from app.db.users import ROLES, count_enabled_admins, get_user, list_users, set_user_enabled, update_user_role
from app.templates.layout import page

router = APIRouter()


def require_admin(user: dict) -> None:
    if (user.get("role") or "").lower() != "admin":
        raise HTTPException(status_code=403, detail="Only admins can manage users")


def render_role_options(selected: str) -> str:
    options = []
    for role in ROLES:
        selected_attr = " selected" if selected == role else ""
        options.append(f'<option value="{role}"{selected_attr}>{role}</option>')
    return "".join(options)


def render_enabled_pill(enabled) -> str:
    if enabled:
        return '<span class="pill pill-success">enabled</span>'
    return '<span class="pill pill-muted">disabled</span>'


@router.get("/admin/users", response_class=HTMLResponse)
def users_page(request: Request, message: str = "", error: str = "", user=Depends(require_user)):
    require_admin(user)

    notice = ""
    if message:
        notice = f'<p class="alert">{html.escape(message)}</p>'
    if error:
        notice = f'<p class="alert alert-danger">{html.escape(error)}</p>'

    rows = ""
    for managed_user in list_users():
        user_id = int(managed_user.get("id"))
        user_id_html = html.escape(str(user_id))
        username = html.escape(managed_user.get("username", "") or "")
        display_name = html.escape(managed_user.get("display_name", "") or "")
        email = html.escape(managed_user.get("email", "") or "")
        role = html.escape(managed_user.get("role", "") or "")
        created_at = html.escape(managed_user.get("created_at", "") or "")
        last_login_at = html.escape(managed_user.get("last_login_at", "") or "")
        enabled = bool(managed_user.get("is_enabled", True))
        toggle_label = "Disable" if enabled else "Enable"
        toggle_action = "disable" if enabled else "enable"

        rows += f"""
        <tr>
            <td>{user_id_html}</td>
            <td><strong>{username}</strong></td>
            <td>{display_name}</td>
            <td>{email}</td>
            <td>
                <form method="post" action="/portal/admin/users/{user_id_html}/role" class="inline-form">
                    <select name="role">{render_role_options(role)}</select>
                    <button type="submit" class="btn-secondary">Save</button>
                </form>
            </td>
            <td>{render_enabled_pill(enabled)}</td>
            <td>{created_at}</td>
            <td>{last_login_at}</td>
            <td class="actions-cell">
                <form method="post" action="/portal/admin/users/{user_id_html}/{toggle_action}" class="inline-form">
                    <button type="submit" class="btn-secondary">{toggle_label}</button>
                </form>
            </td>
        </tr>
        """

    if not rows:
        rows = '<tr><td colspan="9">No users found.</td></tr>'

    return page(
        "Users",
        f"""
        <div class="card">
            <h2>Users</h2>
            <p class="muted">Administration of portal users and roles.</p>
            {notice}
        </div>

        <div class="card">
            <h2>User List</h2>
            <table>
                <tr>
                    <th>ID</th>
                    <th>Username</th>
                    <th>Display name</th>
                    <th>Email</th>
                    <th>Role</th>
                    <th>Status</th>
                    <th>Created</th>
                    <th>Last login</th>
                    <th>Actions</th>
                </tr>
                {rows}
            </table>
        </div>
        """,
        user=user,
    )


@router.post("/admin/users/{user_id}/role")
def update_role_action(user_id: int, role: str = Form(...), user=Depends(require_user)):
    require_admin(user)
    target = get_user(user_id)
    if not target:
        raise HTTPException(status_code=404, detail="User not found")
    if role not in ROLES:
        raise HTTPException(status_code=400, detail="Invalid role")

    old_role = (target.get("role") or "").lower()
    if old_role == "admin" and role != "admin" and count_enabled_admins(excluding_user_id=user_id) == 0:
        return RedirectResponse(
            url="/portal/admin/users?error=" + quote("Cannot remove admin role from the last enabled admin."),
            status_code=303,
        )

    update_user_role(user_id, role)
    if old_role != role:
        log_audit_event(
            user,
            action="user.role.updated",
            target_type="user",
            target_id=user_id,
            metadata={
                "username": target.get("username"),
                "old_role": old_role,
                "new_role": role,
            },
        )

    return RedirectResponse(url="/portal/admin/users?message=" + quote("User role updated."), status_code=303)


@router.post("/admin/users/{user_id}/disable")
def disable_user_action(user_id: int, user=Depends(require_user)):
    require_admin(user)
    target = get_user(user_id)
    if not target:
        raise HTTPException(status_code=404, detail="User not found")
    if (target.get("role") or "").lower() == "admin" and count_enabled_admins(excluding_user_id=user_id) == 0:
        return RedirectResponse(
            url="/portal/admin/users?error=" + quote("Cannot disable the last enabled admin."),
            status_code=303,
        )

    set_user_enabled(user_id, False)
    log_audit_event(
        user,
        action="user.disabled",
        target_type="user",
        target_id=user_id,
        metadata={"username": target.get("username")},
    )
    return RedirectResponse(url="/portal/admin/users?message=" + quote("User disabled."), status_code=303)


@router.post("/admin/users/{user_id}/enable")
def enable_user_action(user_id: int, user=Depends(require_user)):
    require_admin(user)
    target = get_user(user_id)
    if not target:
        raise HTTPException(status_code=404, detail="User not found")

    set_user_enabled(user_id, True)
    log_audit_event(
        user,
        action="user.enabled",
        target_type="user",
        target_id=user_id,
        metadata={"username": target.get("username")},
    )
    return RedirectResponse(url="/portal/admin/users?message=" + quote("User enabled."), status_code=303)