package docnotify

import (
	"context"
	"fmt"
	"strings"

	"chat-agent-system/internal/ctxmgr"
	"chat-agent-system/internal/docgov"
	"chat-agent-system/internal/notification"
)

// LifecycleAction identifies a governance transition for routing.
type LifecycleAction string

const (
	LifecycleSubmitReview    LifecycleAction = "submit_review"
	LifecycleReviewApprove   LifecycleAction = "review_approve"
	LifecycleReviewReject    LifecycleAction = "review_reject"
	LifecycleApproverApprove LifecycleAction = "approver_approve"
	LifecycleApproverReject  LifecycleAction = "approver_reject"
	LifecycleReopen          LifecycleAction = "reopen"
)

// RecipientForDocEvent resolves the duty-holder inbox recipient for a document event.
func RecipientForDocEvent(doc *docgov.DocumentRecord, eventType string) int64 {
	if doc == nil {
		return 0
	}
	switch eventType {
	case notification.EventDocReviewRequested:
		if doc.ReviewerID > 0 {
			return doc.ReviewerID
		}
	case notification.EventDocApprovalRequested:
		if doc.ApproverID > 0 {
			return doc.ApproverID
		}
	case notification.EventDocRejected, notification.EventDocReopened, notification.EventDocPendingSupplements:
		if doc.AuthorID > 0 {
			return doc.AuthorID
		}
	case notification.EventDocApproved:
		if doc.AuthorID > 0 {
			return doc.AuthorID
		}
	}
	if doc.AuthorID > 0 {
		return doc.AuthorID
	}
	return 0
}

// EmitLifecycleParams carries optional chat side channels.
type EmitLifecycleParams struct {
	Notify    notificationEmitter
	Digest    digestUpserter
	Chat      *ctxmgr.ContextManager
	Action    LifecycleAction
	Doc       *docgov.DocumentRecord
	ActorID   int64
	ActorName string
	Detail    string
}

type digestUpserter interface {
	UpsertDocumentDigest(ctx context.Context, p notification.UpsertDigestParams) error
}

// EmitLifecycle notifies the duty holder for a governance transition.
func EmitLifecycle(ctx context.Context, p EmitLifecycleParams) {
	if p.Doc == nil || p.Notify == nil || !p.Notify.Available() {
		return
	}
	eventType, notifType, title, body, severity := lifecycleCopy(p.Action, p.Doc, p.ActorName, p.Detail)
	if eventType == "" {
		return
	}
	recipient := RecipientForDocEvent(p.Doc, eventType)
	if recipient <= 0 {
		return
	}
	payload := notification.DocumentEventPayload{
		ProjectID: p.Doc.ProjectID, DocID: p.Doc.DocID, DocTitle: p.Doc.Title,
		Summary: truncateLifecycle(p.Detail, 80),
	}
	dedupe := fmt.Sprintf("doc_lifecycle:%s:%s:%d:%s", p.Action, p.Doc.DocID, recipient, p.Doc.CurrentState)
	_, _ = p.Notify.EmitDocumentEvent(ctx, eventType, notifType, title, body, dedupe, recipient, payload)

	if p.Digest != nil && severity == notification.SeverityActionRequired {
		kind := digestKindForEvent(eventType)
		if kind != "" {
			_ = p.Digest.UpsertDocumentDigest(ctx, notification.UpsertDigestParams{
				UserID: recipient, ProjectID: p.Doc.ProjectID, DigestKind: kind,
				DocID: p.Doc.DocID, DocTitle: p.Doc.Title, Severity: severity,
				ActorID: p.ActorID, ActorName: p.ActorName, Summary: truncateLifecycle(p.Detail, 60),
			})
		}
	}

	if p.Chat != nil {
		_ = PostProjectNotice(ctx, p.Chat, p.Doc.ProjectID, recipient, body, map[string]any{
			"doc_id": p.Doc.DocID, "action": string(p.Action), "event": eventType,
		})
	}
}

func digestKindForEvent(eventType string) string {
	switch eventType {
	case notification.EventDocReviewRequested:
		return notification.DigestKindReviewRequested
	case notification.EventDocApprovalRequested:
		return notification.DigestKindApprovalRequested
	case notification.EventDocPendingSupplements:
		return notification.DigestKindPendingSupplements
	default:
		return ""
	}
}

func lifecycleCopy(action LifecycleAction, doc *docgov.DocumentRecord, actorName, detail string) (eventType, notifType, title, body, severity string) {
	titleDoc := strings.TrimSpace(doc.Title)
	if titleDoc == "" {
		titleDoc = doc.DocID
	}
	actor := strings.TrimSpace(actorName)
	if actor == "" {
		actor = "成员"
	}
	reason := strings.TrimSpace(detail)
	switch action {
	case LifecycleSubmitReview:
		return notification.EventDocReviewRequested, notification.TypeDocReviewRequested,
			fmt.Sprintf("《%s》待您审核", titleDoc),
			fmt.Sprintf("%s 已送审，请审核本文档。", actor),
			notification.SeverityActionRequired
	case LifecycleReviewApprove:
		return notification.EventDocApprovalRequested, notification.TypeDocApprovalRequested,
			fmt.Sprintf("《%s》待您批准", titleDoc),
			fmt.Sprintf("%s 审核已通过，请批准本文档。", actor),
			notification.SeverityActionRequired
	case LifecycleReviewReject, LifecycleApproverReject:
		msg := fmt.Sprintf("%s 驳回了《%s》。", actor, titleDoc)
		if reason != "" {
			msg += "原因：" + reason
		}
		return notification.EventDocRejected, notification.TypeDocRejected,
			fmt.Sprintf("《%s》已被驳回", titleDoc), msg,
			notification.SeverityActionRequired
	case LifecycleApproverApprove:
		return notification.EventDocApproved, notification.TypeDocApproved,
			fmt.Sprintf("《%s》已批准归档", titleDoc),
			fmt.Sprintf("%s 已终审批准，《%s》已归档锁定。", actor, titleDoc),
			notification.SeverityInfo
	case LifecycleReopen:
		return notification.EventDocReopened, notification.TypeDocReopened,
			fmt.Sprintf("《%s》已重开修订", titleDoc),
			fmt.Sprintf("%s 批准重开修订，《%s》已回编制期。", actor, titleDoc),
			notification.SeverityActionRequired
	default:
		return "", "", "", "", ""
	}
}

func truncateLifecycle(s string, n int) string {
	r := []rune(strings.TrimSpace(s))
	if len(r) <= n {
		return string(r)
	}
	return string(r[:n]) + "…"
}