openapi: 3.0.3
info: { title: Invoice API, version: 1.0.0 }
servers: [ { url: https://your-domain.com/api/v1 } ]
tags: [ { name: Invoices } ]
security: [ { bearerAuth: [] } ]

paths:
  /invoices:
    get:
      tags: [Invoices]
      summary: List invoices
      parameters:
        - in: query
          name: page
          schema: { type: integer, default: 1 }
        - in: query
          name: per_page
          schema: { type: integer, default: 20 }
        - in: query
          name: parent_id
          schema: { type: integer }
        - in: query
          name: status
          schema: { type: string }
      responses:
        "200": { description: Invoices retrieved }
    post:
      tags: [Invoices]
      summary: Create invoice
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required: [invoice_number, total_amount, issue_date, status]
              properties:
                parent_id: { type: integer }
                invoice_number: { type: string }
                total_amount: { type: number }
                balance: { type: number }
                paid_amount: { type: number }
                school_year: { type: string }
                semester: { type: string }
                issue_date: { type: string, format: date-time }
                due_date: { type: string, format: date-time }
                status: { type: string }
                description: { type: string }
      responses:
        "201": { description: Invoice created }

  /invoices/{id}:
    get:
      tags: [Invoices]
      summary: Get invoice by ID
      parameters:
        - in: path
          name: id
          required: true
          schema: { type: integer }
      responses:
        "200": { description: Invoice }
        "404": { description: Not found }
    put:
      tags: [Invoices]
      summary: Update invoice
      parameters:
        - in: path
          name: id
          required: true
          schema: { type: integer }
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                status: { type: string }
                paid_amount: { type: number }
                balance: { type: number }
                description: { type: string }
      responses:
        "200": { description: Invoice updated }
    delete:
      tags: [Invoices]
      summary: Delete invoice
      parameters:
        - in: path
          name: id
          required: true
          schema: { type: integer }
      responses:
        "200": { description: Invoice deleted }

  /invoices/parent/{id}:
    get:
      tags: [Invoices]
      summary: List invoices by parent
      parameters:
        - in: path
          name: id
          required: true
          schema: { type: integer }
      responses:
        "200": { description: Parent invoices list }