// Package control 定义流程暂停、继续与取消的版本化操作；解除暂停不会清除核查或停止意图。
package control

import (
	"context"
	"strings"
	"unicode/utf8"

	"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"
	"git.yuntuo.hk/k2safe/orbit/weave/instance"
)

const Action = "workflows:control"

// Input 的稳定操作身份由方法参数传入；并发控制只使用control_revision，不与后台结果版本竞争。
type Input struct {
	Operation               string `json:"operation"`                        // Operation 为PAUSE、RESUME或CANCEL；终结实例不接受新控制操作。
	ExpectedControlRevision uint64 `json:"expected_control_revision,string"` // ExpectedControlRevision 调用者观察到的控制版本，必须大于0。
	Reason                  string `json:"reason"`                           // Reason 必填操作原因，最多1024个Unicode字符，进入不可变审计。
}
type Result struct {
	Instance     instance.View `json:"instance"`     // Instance 首次操作提交后的冻结回执；当前结果用实例Get读取。
	Deduplicated bool          `json:"deduplicated"` // Deduplicated 原操作恢复，不重复修改控制版本或计时。
}
type Store interface {
	Apply(context.Context, auth.Token, core.ID, string, Input) (Result, error)
}
type Service struct{ store Store }

func New(store Store) *Service { return &Service{store: store} }
func (s *Service) Apply(ctx context.Context, t auth.Token, id core.ID, key string, in Input) (Result, error) {
	if err := service.ValidateKey(key); err != nil {
		return Result{}, err
	}
	if id.Validate() != nil || in.ExpectedControlRevision == 0 {
		return Result{}, fault.Invalid("workflow id and positive control revision required")
	}
	if in.Operation != "PAUSE" && in.Operation != "RESUME" && in.Operation != "CANCEL" {
		return Result{}, fault.Invalid("workflow operation must be PAUSE, RESUME or CANCEL")
	}
	if !utf8.ValidString(in.Reason) || strings.TrimSpace(in.Reason) == "" || utf8.RuneCountInString(in.Reason) > 1024 || strings.ContainsRune(in.Reason, 0) {
		return Result{}, fault.Invalid("workflow control reason required, maximum 1024 characters")
	}
	return s.store.Apply(ctx, t, id, key, in)
}