import { and, eq, ne } from 'drizzle-orm';
import { NextRequest, NextResponse } from 'next/server';
import { trainingPolicies } from '@/db/schema';
import {
  AUDIT_ACTION,
  AUDIT_MODULE,
  getRequestMetadata,
  logAuditEvent,
  toAuditValue
} from '@/features/audit-logs/server/audit-service';
import type { TrainingPolicyMutationPayload } from '@/features/training-policy/api/types';
import {
  getTrainingPolicyByIdForOrganization,
  getTrainingPolicyByYearForOrganization,
  getTrainingPolicyDetailForOrganization,
  normalizeTrainingPolicyPayload,
  serializeTrainingPolicy
} from '@/features/training-policy/server/training-policy-data';
import { AuthError, requirePermission } from '@/lib/auth/session';
import { db } from '@/lib/db';

type Params = { params: Promise<{ id: string }> };

export async function GET(_request: NextRequest, { params }: Params) {
  try {
    const { organization } = await requirePermission('training_policy:read');
    const { id } = await params;
    const policyId = Number(id);
    const policy = await getTrainingPolicyDetailForOrganization({
      id: policyId,
      organizationId: organization.id
    });

    if (!policy) {
      return NextResponse.json(
        { success: false, message: `ไม่พบนโยบายการอบรมรหัส ${id}` },
        { status: 404 }
      );
    }

    return NextResponse.json({
      success: true,
      time: new Date().toISOString(),
      message: 'โหลดรายละเอียดนโยบายการอบรมเรียบร้อยแล้ว',
      policy
    });
  } catch (error) {
    if (error instanceof AuthError) {
      return NextResponse.json({ message: error.message }, { status: error.status });
    }

    console.error('GET /api/training-policies/[id] failed', error);
    return NextResponse.json({ message: 'ไม่สามารถโหลดนโยบายการอบรมได้' }, { status: 500 });
  }
}

export async function PATCH(request: NextRequest, { params }: Params) {
  try {
    const { organization, session } = await requirePermission('training_policy:write');
    const requestMetadata = getRequestMetadata(request);
    const { id } = await params;
    const policyId = Number(id);
    const body = normalizeTrainingPolicyPayload(
      (await request.json()) as TrainingPolicyMutationPayload
    );

    const existingPolicy = await getTrainingPolicyByIdForOrganization({
      id: policyId,
      organizationId: organization.id
    });

    if (!existingPolicy) {
      return NextResponse.json(
        { success: false, message: `ไม่พบนโยบายการอบรมรหัส ${id}` },
        { status: 404 }
      );
    }

    const duplicatePolicy = await getTrainingPolicyByYearForOrganization({
      year: body.year,
      organizationId: organization.id,
      excludeId: policyId
    });

    if (duplicatePolicy) {
      return NextResponse.json(
        {
          success: false,
          message: `มีนโยบายการอบรมสำหรับปี ${body.year} อยู่แล้ว`
        },
        { status: 409 }
      );
    }

    const policy = await db.transaction(async (tx) => {
      if (body.isActive) {
        await tx
          .update(trainingPolicies)
          .set({ isActive: false, updatedAt: new Date() })
          .where(
            and(
              eq(trainingPolicies.organizationId, organization.id),
              ne(trainingPolicies.id, policyId)
            )
          );
      }

      const [updatedPolicy] = await tx
        .update(trainingPolicies)
        .set({
          year: body.year,
          totalHours: body.totalHours,
          kHours: body.kHours,
          sHours: body.sHours,
          aHours: body.aHours,
          isActive: body.isActive,
          updatedAt: new Date()
        })
        .where(and(eq(trainingPolicies.id, policyId), eq(trainingPolicies.organizationId, organization.id)))
        .returning();

      return updatedPolicy;
    });

    const serializedPolicy = serializeTrainingPolicy(policy, {
      updatedByName: session.user.name ?? null
    });

    await logAuditEvent({
      organizationId: organization.id,
      userId: session.user.id,
      module: AUDIT_MODULE.TRAINING_POLICY,
      action: AUDIT_ACTION.UPDATE,
      entityName: `ปี ${policy.year}`,
      entityId: policy.id,
      oldValue: toAuditValue(serializeTrainingPolicy(existingPolicy)),
      newValue: toAuditValue(serializedPolicy),
      ...requestMetadata
    });

    return NextResponse.json({
      success: true,
      time: new Date().toISOString(),
      message: 'อัปเดตนโยบายการอบรมเรียบร้อยแล้ว',
      policy: serializedPolicy
    });
  } catch (error) {
    if (error instanceof AuthError) {
      return NextResponse.json({ message: error.message }, { status: error.status });
    }

    console.error('PATCH /api/training-policies/[id] failed', error);
    return NextResponse.json({ message: 'ไม่สามารถอัปเดตนโยบายการอบรมได้' }, { status: 500 });
  }
}