from __future__ import annotations

from flask import Blueprint, flash, g, redirect, render_template, request, url_for
from flask.typing import ResponseReturnValue

from app.auth import role_required
from app.extensions import db
from app.models import Account
from app.services import (
    ACCOUNT_ROLE_OPTIONS,
    DEFAULT_SHARE_LINK_EXPIRE_DAYS,
    build_share_link_url,
    create_share_link,
    get_account_or_none,
    get_audit_log_or_none,
    get_share_link_or_none,
    is_username_taken,
    list_accounts,
    list_action_types,
    list_audit_logs,
    list_share_links,
    parse_account_form,
    parse_password_reset_form,
    parse_share_link_create_form,
    revoke_share_link,
    serialize_account_snapshot,
    write_audit_log,
)

admin_bp = Blueprint("admin", __name__, url_prefix="/admin")


def _share_link_rows() -> list[dict[str, object]]:
    rows: list[dict[str, object]] = []
    for link in list_share_links():
        rows.append(
            {
                "link": link,
                "public_url": build_share_link_url(link.token),
                "status_label": "已撤销" if link.revoked_at else ("已过期" if link.is_expired() else "有效"),
            }
        )
    return rows


@admin_bp.get("/accounts")
@role_required("admin")
def accounts() -> ResponseReturnValue:
    return render_template(
        "admin/accounts.html",
        accounts=list_accounts(),
        role_options=ACCOUNT_ROLE_OPTIONS,
    )


@admin_bp.route("/accounts/new", methods=["GET", "POST"])
@role_required("admin")
def create_account() -> ResponseReturnValue:
    form_data = {
        "username": "",
        "display_name": "",
        "role": "entry_only",
        "password": "",
        "confirm_password": "",
    }

    if request.method == "POST":
        form_data = {
            "username": request.form.get("username", "").strip(),
            "display_name": request.form.get("display_name", "").strip(),
            "role": request.form.get("role", "").strip(),
            "password": request.form.get("password", ""),
            "confirm_password": request.form.get("confirm_password", ""),
        }
        payload, errors = parse_account_form(dict(request.form), is_create=True)
        if is_username_taken(form_data["username"]):
            errors.append("账号名已存在，请换一个新的账号名。")

        if errors:
            for error in errors:
                flash(error, "error")
            return render_template(
                "admin/account_form.html",
                account=None,
                form_title="新增账号",
                submit_label="创建账号",
                cancel_url=url_for("admin.accounts"),
                role_options=ACCOUNT_ROLE_OPTIONS,
                form_data=form_data,
                is_create=True,
            ), 400

        account = Account(
            username=str(payload["username"]),
            display_name=payload["display_name"] if isinstance(payload["display_name"], str) else None,
            role=str(payload["role"]),
            status="active",
        )
        account.set_password(str(payload["password"]))
        current_account = g.current_account
        if isinstance(current_account, Account):
            account.created_by = current_account.id
            account.updated_by = current_account.id

        db.session.add(account)
        db.session.flush()
        write_audit_log(
            action_type="create_account",
            target_type="account",
            actor=current_account if isinstance(current_account, Account) else None,
            target_id=account.id,
            target_display_name=account.display_name or account.username,
            after_data=serialize_account_snapshot(account),
            commit=False,
        )
        db.session.commit()
        flash(f"已创建账号 {account.username}。", "success")
        return redirect(url_for("admin.accounts"))

    return render_template(
        "admin/account_form.html",
        account=None,
        form_title="新增账号",
        submit_label="创建账号",
        cancel_url=url_for("admin.accounts"),
        role_options=ACCOUNT_ROLE_OPTIONS,
        form_data=form_data,
        is_create=True,
    )


@admin_bp.route("/accounts/<int:account_id>/edit", methods=["GET", "POST"])
@role_required("admin")
def edit_account(account_id: int) -> ResponseReturnValue:
    account = get_account_or_none(account_id)
    if account is None:
        flash("未找到要编辑的账号。", "error")
        return redirect(url_for("admin.accounts"))

    form_data = {
        "username": account.username,
        "display_name": account.display_name or "",
        "role": account.role,
    }

    if request.method == "POST":
        form_data = {
            "username": account.username,
            "display_name": request.form.get("display_name", "").strip(),
            "role": request.form.get("role", "").strip(),
        }
        payload, errors = parse_account_form(dict(request.form), is_create=False)
        if errors:
            for error in errors:
                flash(error, "error")
            return render_template(
                "admin/account_form.html",
                account=account,
                form_title="编辑账号",
                submit_label="保存账号信息",
                cancel_url=url_for("admin.accounts"),
                role_options=ACCOUNT_ROLE_OPTIONS,
                form_data=form_data,
                is_create=False,
            ), 400

        before_snapshot = serialize_account_snapshot(account)
        account.display_name = payload["display_name"] if isinstance(payload["display_name"], str) else None
        account.role = str(payload["role"])
        current_account = g.current_account
        if isinstance(current_account, Account):
            account.updated_by = current_account.id

        after_snapshot = serialize_account_snapshot(account)
        if after_snapshot == before_snapshot:
            flash("没有检测到需要保存的账号变更。", "warning")
            db.session.rollback()
            return redirect(url_for("admin.edit_account", account_id=account.id))

        write_audit_log(
            action_type="update_account",
            target_type="account",
            actor=current_account if isinstance(current_account, Account) else None,
            target_id=account.id,
            target_display_name=account.display_name or account.username,
            before_data=before_snapshot,
            after_data=after_snapshot,
            commit=False,
        )
        db.session.commit()
        flash(f"已更新账号 {account.username}。", "success")
        return redirect(url_for("admin.accounts"))

    return render_template(
        "admin/account_form.html",
        account=account,
        form_title="编辑账号",
        submit_label="保存账号信息",
        cancel_url=url_for("admin.accounts"),
        role_options=ACCOUNT_ROLE_OPTIONS,
        form_data=form_data,
        is_create=False,
    )


@admin_bp.route("/accounts/<int:account_id>/reset-password", methods=["GET", "POST"])
@role_required("admin")
def reset_account_password(account_id: int) -> ResponseReturnValue:
    account = get_account_or_none(account_id)
    if account is None:
        flash("未找到要重置密码的账号。", "error")
        return redirect(url_for("admin.accounts"))

    if request.method == "POST":
        password, errors = parse_password_reset_form(dict(request.form))
        if errors:
            for error in errors:
                flash(error, "error")
            return render_template(
                "admin/account_reset_password.html",
                account=account,
                cancel_url=url_for("admin.accounts"),
            ), 400

        before_snapshot = serialize_account_snapshot(account)
        account.set_password(str(password))
        current_account = g.current_account
        if isinstance(current_account, Account):
            account.updated_by = current_account.id

        write_audit_log(
            action_type="reset_password",
            target_type="account",
            actor=current_account if isinstance(current_account, Account) else None,
            target_id=account.id,
            target_display_name=account.display_name or account.username,
            before_data=before_snapshot,
            after_data=serialize_account_snapshot(account),
            commit=False,
        )
        db.session.commit()
        flash(f"已重置账号 {account.username} 的密码。", "success")
        return redirect(url_for("admin.accounts"))

    return render_template(
        "admin/account_reset_password.html",
        account=account,
        cancel_url=url_for("admin.accounts"),
    )


@admin_bp.post("/accounts/<int:account_id>/toggle-status")
@role_required("admin")
def toggle_account_status(account_id: int):
    account = get_account_or_none(account_id)
    if account is None:
        flash("未找到要变更状态的账号。", "error")
        return redirect(url_for("admin.accounts"))

    current_account = g.current_account
    if isinstance(current_account, Account) and current_account.id == account.id and account.status == "active":
        flash("不能停用当前正在使用的管理员账号。", "error")
        return redirect(url_for("admin.accounts"))

    before_snapshot = serialize_account_snapshot(account)
    account.status = "disabled" if account.status == "active" else "active"
    if isinstance(current_account, Account):
        account.updated_by = current_account.id

    write_audit_log(
        action_type="toggle_account_status",
        target_type="account",
        actor=current_account if isinstance(current_account, Account) else None,
        target_id=account.id,
        target_display_name=account.display_name or account.username,
        before_data=before_snapshot,
        after_data=serialize_account_snapshot(account),
        commit=False,
    )
    db.session.commit()
    flash(f"已将账号 {account.username} 设为{'停用' if account.status == 'disabled' else '启用'}。", "success")
    return redirect(url_for("admin.accounts"))


@admin_bp.get("/audit-logs")
@role_required("admin")
def audit_logs() -> ResponseReturnValue:
    actor_user_id = request.args.get("actor_user_id", type=int)
    action_type = request.args.get("action_type", "").strip()
    from_date = request.args.get("from_date", "").strip()
    to_date = request.args.get("to_date", "").strip()

    return render_template(
        "admin/audit_logs.html",
        logs=list_audit_logs(
            actor_user_id=actor_user_id,
            action_type=action_type,
            from_date=from_date,
            to_date=to_date,
        ),
        accounts=list_accounts(),
        action_types=list_action_types(),
        selected_actor_user_id=actor_user_id,
        selected_action_type=action_type,
        from_date=from_date,
        to_date=to_date,
    )


@admin_bp.get("/audit-logs/<int:log_id>")
@role_required("admin")
def audit_log_detail(log_id: int) -> ResponseReturnValue:
    log = get_audit_log_or_none(log_id)
    if log is None:
        flash("未找到要查看的审计日志。", "error")
        return redirect(url_for("admin.audit_logs"))

    return render_template("admin/audit_log_detail.html", log=log)


@admin_bp.route("/share-links", methods=["GET", "POST"])
@role_required("admin")
def share_links() -> ResponseReturnValue:
    if request.method == "POST":
        payload, errors = parse_share_link_create_form(dict(request.form))
        if errors:
            for error in errors:
                flash(error, "error")
            return render_template(
                "admin/share_links.html",
                link_rows=_share_link_rows(),
                default_expire_days=DEFAULT_SHARE_LINK_EXPIRE_DAYS,
                form_data={
                    "label": request.form.get("label", "").strip(),
                    "expire_days": request.form.get("expire_days", str(DEFAULT_SHARE_LINK_EXPIRE_DAYS)).strip(),
                },
            ), 400

        current_account = g.current_account
        actor = current_account if isinstance(current_account, Account) else None
        label = payload.get("label")
        expire_days = payload.get("expire_days")
        link = create_share_link(
            created_by=actor.id if actor is not None else None,
            label=label if isinstance(label, str) else None,
            expire_days=expire_days if isinstance(expire_days, int) else DEFAULT_SHARE_LINK_EXPIRE_DAYS,
        )
        write_audit_log(
            action_type="create_share_link",
            target_type="share_link",
            actor=actor,
            target_id=link.id,
            target_display_name=build_share_link_url(link.token),
            after_data={
                "token": link.token,
                "label": link.label,
                "expires_at": link.expires_at.isoformat(),
            },
            commit=False,
        )
        db.session.commit()
        flash("已创建分享链接。", "success")
        return redirect(url_for("admin.share_links"))

    return render_template(
        "admin/share_links.html",
        link_rows=_share_link_rows(),
        default_expire_days=DEFAULT_SHARE_LINK_EXPIRE_DAYS,
        form_data={"label": "", "expire_days": str(DEFAULT_SHARE_LINK_EXPIRE_DAYS)},
    )


@admin_bp.post("/share-links/<int:link_id>/revoke")
@role_required("admin")
def revoke_share_link_action(link_id: int) -> ResponseReturnValue:
    link = get_share_link_or_none(link_id)
    if link is None:
        flash("未找到要撤销的分享链接。", "error")
        return redirect(url_for("admin.share_links"))

    updated = revoke_share_link(link)
    if not updated:
        flash("该分享链接已是撤销状态。", "warning")
        return redirect(url_for("admin.share_links"))

    current_account = g.current_account
    actor = current_account if isinstance(current_account, Account) else None
    write_audit_log(
        action_type="revoke_share_link",
        target_type="share_link",
        actor=actor,
        target_id=link.id,
        target_display_name=build_share_link_url(link.token),
        after_data={"revoked_at": link.revoked_at.isoformat() if link.revoked_at else None},
        commit=False,
    )
    db.session.commit()
    flash("分享链接已撤销。", "success")
    return redirect(url_for("admin.share_links"))