{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://tool-ocr.local/schemas/unified-document.json",
  "title": "UnifiedDocument",
  "description": "Unified document representation for dual-track OCR/Direct extraction processing",
  "type": "object",
  "required": ["document_id", "metadata", "pages", "statistics"],
  "properties": {
    "document_id": {
      "type": "string",
      "description": "Unique identifier for the document"
    },
    "metadata": {
      "$ref": "#/definitions/DocumentMetadata"
    },
    "pages": {
      "type": "array",
      "items": {
        "$ref": "#/definitions/Page"
      },
      "description": "List of pages in the document"
    },
    "statistics": {
      "$ref": "#/definitions/DocumentStatistics"
    },
    "processing_errors": {
      "type": "array",
      "items": {
        "$ref": "#/definitions/ProcessingError"
      },
      "default": [],
      "description": "List of any errors encountered during processing"
    }
  },
  "definitions": {
    "DocumentMetadata": {
      "type": "object",
      "required": ["filename", "file_type", "file_size", "created_at", "processing_track", "processing_time"],
      "properties": {
        "filename": {
          "type": "string",
          "description": "Original filename"
        },
        "file_type": {
          "type": "string",
          "description": "File MIME type or extension"
        },
        "file_size": {
          "type": "integer",
          "minimum": 0,
          "description": "File size in bytes"
        },
        "created_at": {
          "type": "string",
          "format": "date-time",
          "description": "Processing timestamp (ISO 8601)"
        },
        "processing_track": {
          "type": "string",
          "enum": ["ocr", "direct", "hybrid"],
          "description": "Processing track used"
        },
        "processing_time": {
          "type": "number",
          "minimum": 0,
          "description": "Processing time in seconds"
        },
        "language": {
          "type": "string",
          "description": "Detected or specified language code"
        },
        "title": {
          "type": "string",
          "description": "Document title from metadata"
        },
        "author": {
          "type": "string",
          "description": "Document author"
        },
        "subject": {
          "type": "string",
          "description": "Document subject"
        },
        "keywords": {
          "type": "array",
          "items": {"type": "string"},
          "description": "Document keywords"
        },
        "producer": {
          "type": "string",
          "description": "PDF producer application"
        },
        "creator": {
          "type": "string",
          "description": "Document creator application"
        },
        "creation_date": {
          "type": "string",
          "format": "date-time",
          "description": "Document creation date"
        },
        "modification_date": {
          "type": "string",
          "format": "date-time",
          "description": "Document last modification date"
        }
      }
    },
    "Page": {
      "type": "object",
      "required": ["page_number", "elements", "dimensions"],
      "properties": {
        "page_number": {
          "type": "integer",
          "minimum": 1,
          "description": "1-based page number"
        },
        "elements": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/DocumentElement"
          },
          "description": "List of elements on the page"
        },
        "dimensions": {
          "$ref": "#/definitions/Dimensions"
        },
        "metadata": {
          "type": "object",
          "additionalProperties": true,
          "description": "Additional page-specific metadata"
        },
        "statistics": {
          "$ref": "#/definitions/PageStatistics"
        }
      }
    },
    "DocumentElement": {
      "type": "object",
      "required": ["element_id", "type", "bbox"],
      "properties": {
        "element_id": {
          "type": "string",
          "description": "Unique identifier for the element"
        },
        "type": {
          "type": "string",
          "enum": [
            "text", "title", "header", "footer", "reference", "equation", "footnote", "caption",
            "list", "list_item",
            "table", "table_cell", "table_caption",
            "image", "figure", "chart", "diagram",
            "section", "paragraph", "page_number", "watermark", "header_group", "body",
            "code", "formula", "signature", "stamp", "logo", "barcode", "qr_code"
          ],
          "description": "Element type (supports all 23 PP-StructureV3 types plus custom ones)"
        },
        "content": {
          "oneOf": [
            {"type": "string"},
            {"$ref": "#/definitions/TableData"},
            {"type": "object"}
          ],
          "description": "Element content (text, table data, or structured data)"
        },
        "content_type": {
          "type": "string",
          "enum": ["text", "table", "binary"],
          "description": "Type of content when not a simple string"
        },
        "content_length": {
          "type": "integer",
          "description": "Length of binary content in bytes"
        },
        "bbox": {
          "$ref": "#/definitions/BoundingBox"
        },
        "confidence": {
          "type": "number",
          "minimum": 0,
          "maximum": 1,
          "description": "OCR confidence score (0-1)"
        },
        "style": {
          "$ref": "#/definitions/StyleInfo"
        },
        "metadata": {
          "type": "object",
          "additionalProperties": true,
          "description": "Additional element metadata"
        },
        "children": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/DocumentElement"
          },
          "description": "Nested child elements"
        }
      }
    },
    "BoundingBox": {
      "type": "object",
      "required": ["x0", "y0", "x1", "y1"],
      "properties": {
        "x0": {
          "type": "number",
          "description": "Left coordinate"
        },
        "y0": {
          "type": "number",
          "description": "Top coordinate"
        },
        "x1": {
          "type": "number",
          "description": "Right coordinate"
        },
        "y1": {
          "type": "number",
          "description": "Bottom coordinate"
        },
        "width": {
          "type": "number",
          "description": "Width (calculated)"
        },
        "height": {
          "type": "number",
          "description": "Height (calculated)"
        }
      }
    },
    "StyleInfo": {
      "type": "object",
      "properties": {
        "font_name": {
          "type": "string",
          "description": "Font family name"
        },
        "font_size": {
          "type": "number",
          "minimum": 0,
          "description": "Font size in points"
        },
        "font_weight": {
          "type": "string",
          "enum": ["normal", "bold"],
          "description": "Font weight"
        },
        "font_style": {
          "type": "string",
          "enum": ["normal", "italic"],
          "description": "Font style"
        },
        "text_color": {
          "type": "integer",
          "description": "Text color as RGB integer"
        },
        "text_color_rgb": {
          "type": "array",
          "items": {"type": "integer", "minimum": 0, "maximum": 255},
          "minItems": 3,
          "maxItems": 3,
          "description": "Text color as [R, G, B] array"
        },
        "bg_color": {
          "type": "integer",
          "description": "Background color as RGB integer"
        },
        "alignment": {
          "type": "string",
          "enum": ["left", "center", "right", "justify"],
          "description": "Text alignment"
        }
      }
    },
    "TableData": {
      "type": "object",
      "required": ["rows", "cols", "cells"],
      "properties": {
        "rows": {
          "type": "integer",
          "minimum": 0,
          "description": "Number of rows"
        },
        "cols": {
          "type": "integer",
          "minimum": 0,
          "description": "Number of columns"
        },
        "cells": {
          "type": "array",
          "items": {
            "$ref": "#/definitions/TableCell"
          },
          "description": "Table cells"
        },
        "headers": {
          "type": "array",
          "items": {"type": "string"},
          "description": "Header row labels"
        },
        "caption": {
          "type": "string",
          "description": "Table caption"
        }
      }
    },
    "TableCell": {
      "type": "object",
      "required": ["row", "col"],
      "properties": {
        "row": {
          "type": "integer",
          "minimum": 0,
          "description": "Row index (0-based)"
        },
        "col": {
          "type": "integer",
          "minimum": 0,
          "description": "Column index (0-based)"
        },
        "row_span": {
          "type": "integer",
          "minimum": 1,
          "default": 1,
          "description": "Number of rows spanned"
        },
        "col_span": {
          "type": "integer",
          "minimum": 1,
          "default": 1,
          "description": "Number of columns spanned"
        },
        "content": {
          "type": "string",
          "default": "",
          "description": "Cell text content"
        },
        "bbox": {
          "$ref": "#/definitions/BoundingBox"
        },
        "style": {
          "$ref": "#/definitions/StyleInfo"
        }
      }
    },
    "Dimensions": {
      "type": "object",
      "required": ["width", "height"],
      "properties": {
        "width": {
          "type": "number",
          "minimum": 0,
          "description": "Width in pixels or points"
        },
        "height": {
          "type": "number",
          "minimum": 0,
          "description": "Height in pixels or points"
        },
        "dpi": {
          "type": "integer",
          "minimum": 1,
          "description": "Resolution in DPI"
        }
      }
    },
    "DocumentStatistics": {
      "type": "object",
      "required": ["page_count", "total_elements", "total_tables", "total_images"],
      "properties": {
        "page_count": {
          "type": "integer",
          "minimum": 0,
          "description": "Total number of pages"
        },
        "total_elements": {
          "type": "integer",
          "minimum": 0,
          "description": "Total elements across all pages"
        },
        "total_tables": {
          "type": "integer",
          "minimum": 0,
          "description": "Total tables across all pages"
        },
        "total_images": {
          "type": "integer",
          "minimum": 0,
          "description": "Total images across all pages"
        }
      }
    },
    "PageStatistics": {
      "type": "object",
      "required": ["total_elements", "text_elements", "tables", "images"],
      "properties": {
        "total_elements": {
          "type": "integer",
          "minimum": 0
        },
        "text_elements": {
          "type": "integer",
          "minimum": 0
        },
        "tables": {
          "type": "integer",
          "minimum": 0
        },
        "images": {
          "type": "integer",
          "minimum": 0
        }
      }
    },
    "ProcessingError": {
      "type": "object",
      "required": ["error_type", "message"],
      "properties": {
        "error_type": {
          "type": "string",
          "description": "Error classification"
        },
        "message": {
          "type": "string",
          "description": "Error description"
        },
        "page": {
          "type": "integer",
          "description": "Page number where error occurred"
        },
        "element_id": {
          "type": "string",
          "description": "Element ID if applicable"
        },
        "timestamp": {
          "type": "string",
          "format": "date-time",
          "description": "When the error occurred"
        }
      }
    }
  }
}