package runtime

import (
	"context"
	"fmt"
)

// TaskResolution 从冻结实例解析的运行时任务绑定。
type TaskResolution struct {
	ProjectID       int64
	WorkflowInstID  int64
	StageKey        string
	TaskKey         string
	DocTaskInstID   int64
	ExecutorKey     string
	QualityGateKey  string
	TemplateAsset   string
	TemplateVersion int
	AuthorUserID    int64
	ReviewerUserID  int64
	ApproverUserID  int64
}

// LiveInstancePort is the runtime-owned port for reading a live instance snapshot.
// Implementations are wired at the composition root; runtime must not import projectinstance.
type LiveInstancePort interface {
	Available() bool
	GetLiveInstanceDetail(ctx context.Context, projectID int64) (*LiveInstanceView, *VersionView, error)
}

// LiveInstanceView is the runtime-facing projection of a live instance.
type LiveInstanceView struct {
	InstanceID     int64
	ConfigSnapshot WorkflowPlanView
	Stages         []StageInstanceView
}

// WorkflowPlanView carries frozen plan duties needed for ResolveDocTask.
type WorkflowPlanView struct {
	Stages []StagePlanView
}

// StagePlanView is one stage in the frozen plan.
type StagePlanView struct {
	StageKey string
	DocTasks []DocTaskPlanView
}

// DocTaskPlanView carries duty assignments for one doc task.
type DocTaskPlanView struct {
	TaskKey string
	Duties  DutyView
}

// DutyView is the three-role assignment on a frozen doc task.
type DutyView struct {
	AuthorUserID   int64
	ReviewerUserID int64
	ApproverUserID int64
}

// StageInstanceView is one materialized stage in the live snapshot.
type StageInstanceView struct {
	StageKey string
	DocTasks []DocTaskInstanceView
}

// DocTaskInstanceView is one materialized doc task instance.
type DocTaskInstanceView struct {
	ID      int64
	TaskKey string
}

// VersionView is the published definition projection needed for executor/template lookup.
type VersionView struct {
	Definition VersionDefinitionView
}

// VersionDefinitionView holds stages/doc-task defs for lookup.
type VersionDefinitionView struct {
	Stages []StageDefView
}

// StageDefView is one stage definition.
type StageDefView struct {
	Key      string
	DocTasks []DocTaskDefView
}

// DocTaskDefView carries executor/template bindings from the published definition.
type DocTaskDefView struct {
	Key              string
	ExecutorKey      string
	QualityGateKey   string
	TemplateAssetKey string
	TemplateVersion  int
	Template         *TemplateRefView
}

// TemplateRefView is an optional template version ref.
type TemplateRefView struct {
	AssetKey string
	Version  int
}

// Orchestrator 只读冻结快照编排（禁止 flatten 旁路）。
type Orchestrator struct {
	live LiveInstancePort
}

func NewOrchestrator(live LiveInstancePort) *Orchestrator {
	return &Orchestrator{live: live}
}

// ResolveDocTask 由 doc_task_instance_id 解析 executor/模板/三权。
func (o *Orchestrator) ResolveDocTask(ctx context.Context, projectID, docTaskInstID int64) (*TaskResolution, error) {
	if o == nil || o.live == nil || !o.live.Available() {
		return nil, fmt.Errorf("orchestrator unavailable")
	}
	detail, version, err := o.live.GetLiveInstanceDetail(ctx, projectID)
	if err != nil {
		return nil, err
	}
	if detail == nil || version == nil {
		return nil, fmt.Errorf("orchestrator: empty live snapshot")
	}
	plan := detail.ConfigSnapshot
	for _, st := range detail.Stages {
		for _, dt := range st.DocTasks {
			if dt.ID != docTaskInstID {
				continue
			}
			res := &TaskResolution{
				ProjectID:      projectID,
				WorkflowInstID: detail.InstanceID,
				StageKey:       st.StageKey,
				TaskKey:        dt.TaskKey,
				DocTaskInstID:  dt.ID,
			}
			if def := lookupTaskDef(&version.Definition, st.StageKey, dt.TaskKey); def != nil {
				res.ExecutorKey = def.ExecutorKey
				res.QualityGateKey = def.QualityGateKey
				if def.Template != nil {
					res.TemplateAsset = def.Template.AssetKey
					res.TemplateVersion = def.Template.Version
				} else {
					res.TemplateAsset = def.TemplateAssetKey
					res.TemplateVersion = def.TemplateVersion
				}
			}
			matchedDuty := false
			for _, stPlan := range plan.Stages {
				if stPlan.StageKey != st.StageKey {
					continue
				}
				for _, dtPlan := range stPlan.DocTasks {
					if dtPlan.TaskKey != dt.TaskKey {
						continue
					}
					res.AuthorUserID = dtPlan.Duties.AuthorUserID
					res.ReviewerUserID = dtPlan.Duties.ReviewerUserID
					res.ApproverUserID = dtPlan.Duties.ApproverUserID
					matchedDuty = true
				}
			}
			if !matchedDuty {
				return nil, fmt.Errorf("orchestrator: frozen plan has no duties for stage %s task %s", st.StageKey, dt.TaskKey)
			}
			return res, nil
		}
	}
	return nil, fmt.Errorf("doc task instance not in live snapshot")
}

func lookupTaskDef(def *VersionDefinitionView, stageKey, taskKey string) *DocTaskDefView {
	if def == nil {
		return nil
	}
	for _, st := range def.Stages {
		if st.Key != stageKey {
			continue
		}
		for i := range st.DocTasks {
			if st.DocTasks[i].Key == taskKey {
				return &st.DocTasks[i]
			}
		}
	}
	return nil
}