package docgov

import (
	"context"
	"encoding/json"
	"log/slog"
)

// GetDocument 获取文档实体 (优先查内存，未命中查 DB)
func (e *GovernanceEngine) GetDocument(ctx context.Context, docID string) (*DocumentRecord, error) {
	g := e.acquireDocLock(docID)
	defer g.Release()

	if doc, exists := e.memDocsGet(docID); exists {
		return doc, nil
	}
	if e.pool != nil {
		if doc, err := e.loadDocumentFromDBLocked(ctx, docID); err == nil && doc != nil {
			return doc, nil
		}
	}
	return nil, ErrDocumentNotFound
}

// ListAuditLogs 获取文档审计日志
func (e *GovernanceEngine) ListAuditLogs(ctx context.Context, docID string) ([]*AuditLog, error) {
	g := e.acquireDocLock(docID)
	defer g.Release()

	if e.memAuditsEmpty(docID) && e.pool != nil {
		rows, err := e.pool.Query(ctx, `
			SELECT id, doc_id, action, actor_id, actor_name, actor_role, from_state, to_state, details, created_at
			FROM document_audit_logs
			WHERE doc_id = $1
			ORDER BY created_at ASC
		`, docID)
		if err == nil {
			defer rows.Close()
			for rows.Next() {
				var a AuditLog
				var detJSON []byte
				var role, fromSt, toSt string
				var actID *int64
				if err := rows.Scan(&a.ID, &a.DocID, &a.Action, &actID, &a.ActorName, &role, &fromSt, &toSt, &detJSON, &a.CreatedAt); err == nil {
					if actID != nil {
						a.ActorID = *actID
					}
					a.ActorRole = UserRole(role)
					a.FromState = DocumentState(fromSt)
					a.ToState = DocumentState(toSt)
					if len(detJSON) > 0 {
						_ = json.Unmarshal(detJSON, &a.Details)
					}
					e.memAuditsAppend(docID, &a)
				}
			}
			if err := rows.Err(); err != nil {
				slog.Warn("docgov_audit_scan_incomplete", "error", err)
			}
		}
	}

	return e.memAuditsCopy(docID), nil
}

// ListComments 列出文档的所有批注
func (e *GovernanceEngine) ListComments(ctx context.Context, docID string) ([]*DocumentComment, error) {
	g := e.acquireDocLock(docID)
	defer g.Release()

	if e.memCommsEmpty(docID) && e.pool != nil {
		rows, err := e.pool.Query(ctx, `
			SELECT id, doc_id, user_id, user_name, user_role, target_section, comment_type, content, status, created_at
			FROM document_comments
			WHERE doc_id = $1
			ORDER BY created_at ASC
		`, docID)
		if err == nil {
			defer rows.Close()
			for rows.Next() {
				var c DocumentComment
				var uID *int64
				var role, cType string
				if err := rows.Scan(&c.ID, &c.DocID, &uID, &c.UserName, &role, &c.TargetSection, &cType, &c.Content, &c.Status, &c.CreatedAt); err == nil {
					if uID != nil {
						c.UserID = *uID
					}
					c.UserRole = UserRole(role)
					c.CommentType = CommentType(cType)
					e.memCommsAppend(docID, &c, false)
				}
			}
			if err := rows.Err(); err != nil {
				slog.Warn("docgov_comments_scan_incomplete", "error", err)
			}
		}
	}

	return e.memCommsCopy(docID), nil
}

func (e *GovernanceEngine) loadDocumentFromDBLocked(ctx context.Context, docID string) (*DocumentRecord, error) {
	if e.pool == nil {
		return nil, ErrDocumentNotFound
	}
	row := e.pool.QueryRow(ctx, `
		SELECT id, doc_id, project_id, task_key, title, stage, version,
		       current_state, is_locked, is_template_only, content_sha256, work_dir,
		       author_id, author_name, reviewer_id, reviewer_name, approver_id, approver_name,
		       author_claimed, author_claimed_at, author_last_viewed_at, author_last_edited_at,
		       reviewer_claimed, reviewer_claimed_at, approver_claimed, approver_claimed_at,
		       last_rejected_reason, last_rejected_by_role, last_rejected_by_name, last_rejected_at,
		       approved_at, config, created_at, updated_at,
		       COALESCE(lease_holder_type, ''), COALESCE(lease_holder_id, ''), COALESCE(lease_work_dir, ''),
		       lease_expires_at, lease_heartbeat_at, COALESCE(lease_fencing_token, ''),
		   COALESCE(duty_locked, false), COALESCE(duty_policy, ''),
		   COALESCE(review_snapshot_id, 0)
		FROM document_records
		WHERE doc_id = $1
	`, docID)

	var doc DocumentRecord
	var cfgJSON []byte
	var currState string
	var authorID, reviewerID, approverID *int64
	var leaseType, leaseID, leaseWD string
	err := row.Scan(
		&doc.ID, &doc.DocID, &doc.ProjectID, &doc.TaskKey, &doc.Title, &doc.Stage, &doc.Version,
		&currState, &doc.IsLocked, &doc.IsTemplateOnly, &doc.ContentSHA256, &doc.WorkDir,
		&authorID, &doc.AuthorName, &reviewerID, &doc.ReviewerName, &approverID, &doc.ApproverName,
		&doc.AuthorClaimed, &doc.AuthorClaimedAt, &doc.AuthorLastViewedAt, &doc.AuthorLastEditedAt,
		&doc.ReviewerClaimed, &doc.ReviewerClaimedAt, &doc.ApproverClaimed, &doc.ApproverClaimedAt,
		&doc.LastRejectedReason, &doc.LastRejectedByRole, &doc.LastRejectedByName, &doc.LastRejectedAt,
		&doc.ApprovedAt, &cfgJSON, &doc.CreatedAt, &doc.UpdatedAt,
		&leaseType, &leaseID, &leaseWD, &doc.LeaseExpiresAt, &doc.LeaseHeartbeatAt, &doc.LeaseFencingToken,
		&doc.DutyLocked, &doc.DutyPolicy,
		&doc.ReviewSnapshotID,
	)
	if err != nil {
		return nil, err
	}

	doc.CurrentState = DocumentState(currState)
	doc.LeaseHolderType = LeaseHolderType(leaseType)
	doc.LeaseHolderID = leaseID
	doc.LeaseWorkDir = leaseWD
	if authorID != nil {
		doc.AuthorID = *authorID
	}
	if reviewerID != nil {
		doc.ReviewerID = *reviewerID
	}
	if approverID != nil {
		doc.ApproverID = *approverID
	}
	if len(cfgJSON) > 0 {
		_ = json.Unmarshal(cfgJSON, &doc.Config)
	}
	e.memDocsPut(docID, &doc)
	return &doc, nil
}