package mysql

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"

	"git.yuntuo.hk/k2safe/orbit/internal/fault"
	core "git.yuntuo.hk/k2safe/orbit/model"
	"git.yuntuo.hk/k2safe/orbit/platform/auth"
	"git.yuntuo.hk/k2safe/orbit/pulse/service"
)

// CancelTask 将取消意图与开始授权串行化；已开始的尝试仍须确认结果或到期核查。
func (s *TaskStore) CancelTask(ctx context.Context, token auth.Token, id core.ID, key string, in service.CancelInput) (service.CancelResult, error) {
	var out service.CancelResult
	err := s.transaction(ctx, token, "tasks:cancel", func(tx *sql.Tx, p auth.Permissions) error {
		view, err := readTask(ctx, tx, token.NamespaceID, id, false)
		if err != nil {
			return err
		}
		if !p.AllowsQueue(view.QueueID) {
			return fault.NotFound
		}
		identity, cached, err := reserveIdentity(ctx, tx, token.NamespaceID, "task.cancel", string(id), key, "task", id, in)
		if err != nil {
			return err
		}
		if cached != nil {
			if err := json.Unmarshal(cached, &out); err != nil {
				return err
			}
			out.Deduplicated = true
			return nil
		}
		// 应用额度 → 队列 → 任务 → 尝试 → 许可；取消不获取 Worker 会话锁。
		if _, _, err := lockQueue(ctx, tx, token.NamespaceID, view.QueueID); err != nil {
			return err
		}
		task, err := readExecutionTask(ctx, tx, token.NamespaceID, id)
		if err != nil {
			return err
		}
		view = task.view
		if view.Revision != in.ExpectedRevision || view.State.Terminal() || view.CancelRequestedAt != nil {
			return fault.Conflict
		}
		var owner sql.NullString
		if err := tx.QueryRowContext(ctx, "SELECT owner_kind FROM pulse_tasks WHERE namespace_id=? AND id=?", token.NamespaceID, id).Scan(&owner); err != nil {
			return err
		}
		if owner.Valid && owner.String != "schedule" {
			return fault.Conflict
		}
		now, err := dbNow(ctx, tx)
		if err != nil {
			return err
		}
		out.Task, err = cancelExecutionTask(ctx, tx, token.NamespaceID, task, now, "CANCEL_REQUESTED")
		if err != nil {
			return err
		}
		if err := appendAudit(ctx, tx, token, identity, id, "task", "task.cancel", in.Reason, map[string]any{"state": view.State, "revision": fmt.Sprint(view.Revision)}, map[string]any{"state": out.Task.State, "revision": fmt.Sprint(out.Task.Revision), "cancel_requested_at": now}); err != nil {
			return err
		}
		return saveIdentity(ctx, tx, token.NamespaceID, identity, out)
	})
	return out, err
}