package projectinstance

import (
	"context"
	"fmt"

	"chat-agent-system/internal/workflowdef"
)

// ReassignDocTaskDutiesInput 激活后受控改派单文档三职。
type ReassignDocTaskDutiesInput struct {
	TaskKey    string  `json:"task_key"`
	Duties     DocDuty `json:"duties"`
	DutyPolicy string  `json:"duty_policy,omitempty"`
}

// DocumentDutyProjector 将实例职责投影到 document_records（含 duty_locked 行）。
type DocumentDutyProjector interface {
	ProjectDocTaskDuties(ctx context.Context, projectID int64, taskKey string, duties DocDuty, dutyPolicy string, names DutyDisplayNames) error
}

// DutyDisplayNames 投影用显示名；空则保留原名或写占位。
type DutyDisplayNames struct {
	AuthorName   string
	ReviewerName string
	ApproverName string
}

// DocTaskBusyChecker 改派前检查小队任务是否占用文档。
type DocTaskBusyChecker interface {
	DocTaskSquadBusy(ctx context.Context, projectID int64, taskKey string) (busy bool, reason string, err error)
}

// ReassignDocTaskDuties 在 live 实例上改派单个文档任务职责。
// 不放开规划冻结：不修改 lifecycle / selection，仅更新 snapshot 与 assignments。
func (s *Service) ReassignDocTaskDuties(
	ctx context.Context,
	projectID, userID int64,
	allowed bool,
	in ReassignDocTaskDutiesInput,
) (*ProjectSettings, error) {
	if !allowed {
		return nil, ErrForbiddenDutyReassign
	}
	if projectID <= 0 || in.TaskKey == "" {
		return nil, ErrInvalidPlan
	}
	if !s.Available() {
		return nil, ErrNotAvailable
	}

	live, err := s.store.GetLiveInstance(ctx, projectID)
	if err != nil {
		return nil, err
	}
	if live == nil {
		return nil, ErrInstanceNotFound
	}

	plan := cloneWorkflowPlan(live.ConfigSnapshot)
	dt := findDocTaskPlanMutable(&plan, in.TaskKey)
	if dt == nil || !dt.Enabled {
		return nil, ErrDocTaskNotFound
	}
	if in.DutyPolicy != "" {
		dt.DutyPolicy = in.DutyPolicy
	}
	dt.Duties = in.Duties
	*dt = normalizeDocTaskDuties(*dt)

	version, verErr := s.resolvePublishedVersion(ctx, plan)
	if verErr != nil {
		return nil, verErr
	}
	td := workflowdef.DocTaskDef{Key: dt.TaskKey, Required: true}
	if def := findDocTaskDefInVersion(version.Definition, dt.TaskKey); def != nil {
		td = *def
	}
	issues := validateDocTaskDuties(*dt, td)
	if len(issues) > 0 {
		return nil, newValidationError(workflowdef.ValidationResult{Valid: false, Issues: issues})
	}

	plan = normalizeWorkflowPlanDuties(plan)
	if planUsesAuthorOnly(plan) {
		if _, err := s.requireAuthorOnlyAllowed(ctx); err != nil {
			return nil, err
		}
	}
	if err := s.checkActiveMembers(ctx, projectID, plan); err != nil {
		return nil, err
	}

	if s.busyChecker != nil {
		busy, reason, busyErr := s.busyChecker.DocTaskSquadBusy(ctx, projectID, in.TaskKey)
		if busyErr != nil {
			return nil, busyErr
		}
		if busy {
			if reason == "" {
				reason = fmt.Sprintf("文档任务 %s 小队执行中，完成后可更换负责人", in.TaskKey)
			}
			return nil, &DocTaskBusyError{TaskKey: in.TaskKey, Reason: reason}
		}
	}

	updated, err := s.store.UpdateLiveDocTaskDuties(ctx, projectID, in.TaskKey, plan, userID)
	if err != nil {
		return nil, err
	}

	updatedDT := findDocTaskPlan(updated.ConfigSnapshot, in.TaskKey)
	if updatedDT != nil && s.projector != nil {
		mode, effective, _ := ResolveDocTaskDuty(*updatedDT)
		if mode != DutyModeNone {
			_ = s.projector.ProjectDocTaskDuties(ctx, projectID, in.TaskKey, effective, updatedDT.DutyPolicy, DutyDisplayNames{})
		}
	}

	return s.GetSettings(ctx, projectID, userID, true)
}

func (s *Service) SetDocumentDutyProjector(p DocumentDutyProjector) {
	if s == nil {
		return
	}
	s.projector = p
}

func (s *Service) SetDocTaskBusyChecker(c DocTaskBusyChecker) {
	if s == nil {
		return
	}
	s.busyChecker = c
}

func findDocTaskPlanMutable(plan *WorkflowPlan, taskKey string) *DocTaskPlan {
	if plan == nil {
		return nil
	}
	for i := range plan.Stages {
		for j := range plan.Stages[i].DocTasks {
			if plan.Stages[i].DocTasks[j].TaskKey == taskKey {
				return &plan.Stages[i].DocTasks[j]
			}
		}
	}
	return nil
}

func findDocTaskDefInVersion(def workflowdef.VersionDefinition, taskKey string) *workflowdef.DocTaskDef {
	for _, st := range def.Stages {
		for i := range st.DocTasks {
			if st.DocTasks[i].Key == taskKey {
				return &st.DocTasks[i]
			}
		}
	}
	return nil
}

func cloneWorkflowPlan(in WorkflowPlan) WorkflowPlan {
	out := in
	out.Stages = make([]StagePlan, len(in.Stages))
	for i, st := range in.Stages {
		out.Stages[i] = st
		out.Stages[i].DocTasks = append([]DocTaskPlan(nil), st.DocTasks...)
	}
	return out
}