openapi: 3.0.3
info:
  title: HCFS API
  description: |
    Context-Aware Hierarchical Context File System API
    
    A production-grade API for managing, searching, and analyzing hierarchical context data with advanced AI capabilities.
    
    ## Features
    
    - **Context Management**: Full CRUD operations for hierarchical contexts
    - **Intelligent Search**: Semantic, keyword, and hybrid search capabilities
    - **Batch Operations**: High-throughput batch processing
    - **Real-time Updates**: WebSocket streaming for live updates
    - **Enterprise Security**: JWT and API key authentication
    - **Performance Monitoring**: Built-in metrics and health checks
    
    ## Authentication
    
    This API supports two authentication methods:
    
    1. **API Key**: Include `X-API-Key` header with your API key
    2. **JWT Token**: Include `Authorization: Bearer <token>` header
    
    Contact support@hcfs.dev for API access.
    
  version: 2.0.0
  contact:
    name: HCFS Support
    email: support@hcfs.dev
    url: https://hcfs.dev/support
  license:
    name: MIT
    url: https://opensource.org/licenses/MIT
  termsOfService: https://hcfs.dev/terms

servers:
  - url: https://api.hcfs.dev/v1
    description: Production server
  - url: https://staging-api.hcfs.dev/v1
    description: Staging server
  - url: http://localhost:8000
    description: Local development server

paths:
  /health:
    get:
      summary: Health Check
      description: Check the health status of the API and its components
      operationId: getHealth
      tags:
        - System
      responses:
        '200':
          description: System is healthy
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HealthResponse'
              example:
                status: "healthy"
                version: "2.0.0"
                uptime_seconds: 86400
                components:
                  - name: "database"
                    status: "healthy"
                    response_time_ms: 2.5
                  - name: "embeddings"
                    status: "healthy"
                    response_time_ms: 15.2

  /api/v1/contexts:
    get:
      summary: List Contexts
      description: Retrieve a paginated list of contexts with optional filtering
      operationId: listContexts
      tags:
        - Contexts
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      parameters:
        - name: page
          in: query
          description: Page number (starts from 1)
          schema:
            type: integer
            minimum: 1
            default: 1
        - name: page_size
          in: query
          description: Number of items per page
          schema:
            type: integer
            minimum: 1
            maximum: 1000
            default: 20
        - name: path_prefix
          in: query
          description: Filter by path prefix
          schema:
            type: string
            example: "/docs"
        - name: author
          in: query
          description: Filter by author
          schema:
            type: string
        - name: status
          in: query
          description: Filter by status
          schema:
            $ref: '#/components/schemas/ContextStatus'
        - name: sort_by
          in: query
          description: Sort field
          schema:
            type: string
            enum: [created_at, updated_at, path, author]
            default: created_at
        - name: sort_order
          in: query
          description: Sort order
          schema:
            type: string
            enum: [asc, desc]
            default: desc
      responses:
        '200':
          description: List of contexts
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ContextListResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '429':
          $ref: '#/components/responses/RateLimited'

    post:
      summary: Create Context
      description: Create a new context with automatic embedding generation
      operationId: createContext
      tags:
        - Contexts
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ContextCreate'
            example:
              path: "/docs/api-guide"
              content: "This is a comprehensive guide to using the HCFS API..."
              summary: "API usage guide"
              author: "docs-team"
              tags: ["documentation", "api", "guide"]
              metadata:
                category: "documentation"
                difficulty: "beginner"
      responses:
        '200':
          description: Context created successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ContextDetailResponse'
        '400':
          $ref: '#/components/responses/ValidationError'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '429':
          $ref: '#/components/responses/RateLimited'

  /api/v1/contexts/{context_id}:
    get:
      summary: Get Context
      description: Retrieve a specific context by ID
      operationId: getContext
      tags:
        - Contexts
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      parameters:
        - name: context_id
          in: path
          required: true
          description: Context identifier
          schema:
            type: integer
            example: 123
      responses:
        '200':
          description: Context details
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ContextDetailResponse'
        '404':
          $ref: '#/components/responses/NotFound'
        '401':
          $ref: '#/components/responses/Unauthorized'

    put:
      summary: Update Context
      description: Update an existing context
      operationId: updateContext
      tags:
        - Contexts
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      parameters:
        - name: context_id
          in: path
          required: true
          description: Context identifier
          schema:
            type: integer
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ContextUpdate'
      responses:
        '200':
          description: Context updated successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ContextDetailResponse'
        '400':
          $ref: '#/components/responses/ValidationError'
        '404':
          $ref: '#/components/responses/NotFound'
        '401':
          $ref: '#/components/responses/Unauthorized'

    delete:
      summary: Delete Context
      description: Delete a context permanently
      operationId: deleteContext
      tags:
        - Contexts
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      parameters:
        - name: context_id
          in: path
          required: true
          description: Context identifier
          schema:
            type: integer
      responses:
        '200':
          description: Context deleted successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SuccessResponse'
        '404':
          $ref: '#/components/responses/NotFound'
        '401':
          $ref: '#/components/responses/Unauthorized'

  /api/v1/search:
    post:
      summary: Search Contexts
      description: |
        Search contexts using various search methods:
        
        - **Semantic Search**: Uses AI embeddings for meaning-based search
        - **Keyword Search**: Traditional text-based search
        - **Hybrid Search**: Combines semantic and keyword search
        - **Fuzzy Search**: Tolerates typos and variations
      operationId: searchContexts
      tags:
        - Search
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SearchRequest'
            examples:
              semantic_search:
                summary: Semantic Search
                value:
                  query: "machine learning algorithms"
                  search_type: "semantic"
                  top_k: 10
                  similarity_threshold: 0.7
              hybrid_search:
                summary: Hybrid Search
                value:
                  query: "neural networks deep learning"
                  search_type: "hybrid"
                  semantic_weight: 0.7
                  top_k: 20
                  path_prefix: "/ml"
      responses:
        '200':
          description: Search results
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/SearchResponse'
        '400':
          $ref: '#/components/responses/ValidationError'
        '401':
          $ref: '#/components/responses/Unauthorized'

  /api/v1/contexts/batch:
    post:
      summary: Batch Create Contexts
      description: Create multiple contexts in a single operation
      operationId: batchCreateContexts
      tags:
        - Batch Operations
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/BatchContextCreate'
      responses:
        '200':
          description: Batch operation results
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/BatchResponse'
        '400':
          $ref: '#/components/responses/ValidationError'
        '401':
          $ref: '#/components/responses/Unauthorized'

  /api/v1/stats:
    get:
      summary: Get Statistics
      description: Retrieve comprehensive system statistics and metrics
      operationId: getStatistics
      tags:
        - Analytics
      security:
        - ApiKeyAuth: []
        - BearerAuth: []
      responses:
        '200':
          description: System statistics
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StatsResponse'
        '401':
          $ref: '#/components/responses/Unauthorized'

  /metrics:
    get:
      summary: Prometheus Metrics
      description: Get Prometheus-compatible metrics for monitoring
      operationId: getMetrics
      tags:
        - System
      responses:
        '200':
          description: Prometheus metrics
          content:
            text/plain:
              schema:
                type: string
              example: |
                # HELP hcfs_requests_total Total HTTP requests
                # TYPE hcfs_requests_total counter
                hcfs_requests_total{method="GET",endpoint="/api/v1/contexts",status="200"} 1250
                
                # HELP hcfs_request_duration_seconds HTTP request duration
                # TYPE hcfs_request_duration_seconds histogram
                hcfs_request_duration_seconds_bucket{le="0.1"} 800
                hcfs_request_duration_seconds_bucket{le="0.5"} 1200
                hcfs_request_duration_seconds_bucket{le="1.0"} 1245
                hcfs_request_duration_seconds_bucket{le="+Inf"} 1250

components:
  securitySchemes:
    ApiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
      description: API key for authentication
    
    BearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: JWT token for authentication

  schemas:
    ContextStatus:
      type: string
      enum: [active, archived, deleted, draft]
      description: Status of the context
      example: active

    SearchType:
      type: string
      enum: [semantic, keyword, hybrid, fuzzy]
      description: Type of search to perform
      example: semantic

    HealthStatus:
      type: string
      enum: [healthy, degraded, unhealthy]
      description: Health status indicator

    ComponentHealth:
      type: object
      properties:
        name:
          type: string
          description: Component name
        status:
          $ref: '#/components/schemas/HealthStatus'
        response_time_ms:
          type: number
          format: float
          description: Response time in milliseconds
        error_message:
          type: string
          description: Error message if unhealthy
      required: [name, status]

    HealthResponse:
      type: object
      properties:
        status:
          $ref: '#/components/schemas/HealthStatus'
        version:
          type: string
          description: API version
        uptime_seconds:
          type: number
          description: System uptime in seconds
        components:
          type: array
          items:
            $ref: '#/components/schemas/ComponentHealth'
      required: [status, version, uptime_seconds, components]

    Context:
      type: object
      properties:
        id:
          type: integer
          description: Unique context identifier
          example: 123
        path:
          type: string
          description: Hierarchical path of the context
          example: "/docs/api/authentication"
        content:
          type: string
          description: Content of the context
        summary:
          type: string
          description: Brief summary of the context
        author:
          type: string
          description: Author of the context
          example: "john.doe"
        tags:
          type: array
          items:
            type: string
          description: Tags associated with the context
          example: ["api", "authentication", "security"]
        metadata:
          type: object
          additionalProperties: true
          description: Additional metadata
        status:
          $ref: '#/components/schemas/ContextStatus'
        created_at:
          type: string
          format: date-time
          description: Creation timestamp
        updated_at:
          type: string
          format: date-time
          description: Last update timestamp
        version:
          type: integer
          description: Context version number
          example: 1
        similarity_score:
          type: number
          format: float
          description: Similarity score (for search results)
          minimum: 0.0
          maximum: 1.0
      required: [id, path, content, status, created_at, updated_at, version]

    ContextCreate:
      type: object
      properties:
        path:
          type: string
          description: Hierarchical path of the context
          example: "/docs/quickstart"
          pattern: "^/.*"
        content:
          type: string
          description: Content of the context
          minLength: 1
          maxLength: 1000000
        summary:
          type: string
          description: Brief summary of the context
          maxLength: 1000
        author:
          type: string
          description: Author of the context
          maxLength: 100
        tags:
          type: array
          items:
            type: string
            maxLength: 50
          description: Tags associated with the context
          maxItems: 20
        metadata:
          type: object
          additionalProperties: true
          description: Additional metadata
      required: [path, content]

    ContextUpdate:
      type: object
      properties:
        content:
          type: string
          description: Updated content
          minLength: 1
          maxLength: 1000000
        summary:
          type: string
          description: Updated summary
          maxLength: 1000
        tags:
          type: array
          items:
            type: string
            maxLength: 50
          maxItems: 20
        metadata:
          type: object
          additionalProperties: true
        status:
          $ref: '#/components/schemas/ContextStatus'

    SearchRequest:
      type: object
      properties:
        query:
          type: string
          description: Search query
          minLength: 1
          maxLength: 1000
          example: "machine learning algorithms"
        search_type:
          $ref: '#/components/schemas/SearchType'
        top_k:
          type: integer
          description: Maximum number of results
          minimum: 1
          maximum: 1000
          default: 10
        similarity_threshold:
          type: number
          format: float
          description: Minimum similarity score
          minimum: 0.0
          maximum: 1.0
          default: 0.0
        path_prefix:
          type: string
          description: Search within path prefix
          example: "/docs"
        semantic_weight:
          type: number
          format: float
          description: Weight for semantic search in hybrid mode
          minimum: 0.0
          maximum: 1.0
          default: 0.7
        filters:
          type: object
          additionalProperties: true
          description: Additional search filters
      required: [query]

    SearchResult:
      type: object
      properties:
        context:
          $ref: '#/components/schemas/Context'
        score:
          type: number
          format: float
          description: Relevance score
          minimum: 0.0
          maximum: 1.0
        explanation:
          type: string
          description: Explanation of why this result was returned
        highlights:
          type: array
          items:
            type: string
          description: Highlighted text snippets
      required: [context, score]

    SearchResponse:
      type: object
      properties:
        data:
          type: array
          items:
            $ref: '#/components/schemas/SearchResult'
        query:
          type: string
          description: Original search query
        search_type:
          $ref: '#/components/schemas/SearchType'
        total_results:
          type: integer
          description: Total number of results found
        search_time_ms:
          type: number
          format: float
          description: Search execution time in milliseconds
        filters_applied:
          type: object
          additionalProperties: true
          description: Filters that were applied
      required: [data, query, search_type, total_results, search_time_ms]

    BatchContextCreate:
      type: object
      properties:
        contexts:
          type: array
          items:
            $ref: '#/components/schemas/ContextCreate'
          minItems: 1
          maxItems: 1000
      required: [contexts]

    BatchOperationResult:
      type: object
      properties:
        success_count:
          type: integer
          description: Number of successful operations
        error_count:
          type: integer
          description: Number of failed operations
        total_items:
          type: integer
          description: Total number of items processed
        created_ids:
          type: array
          items:
            type: integer
          description: IDs of successfully created contexts
        errors:
          type: array
          items:
            type: object
            properties:
              index:
                type: integer
                description: Index of the failed item
              path:
                type: string
                description: Path of the failed context
              error:
                type: string
                description: Error message
      required: [success_count, error_count, total_items]

    PaginationMeta:
      type: object
      properties:
        page:
          type: integer
          description: Current page number
        page_size:
          type: integer
          description: Items per page
        total_items:
          type: integer
          description: Total number of items
        total_pages:
          type: integer
          description: Total number of pages
        has_next:
          type: boolean
          description: Whether there is a next page
        has_previous:
          type: boolean
          description: Whether there is a previous page
      required: [page, page_size, total_items, total_pages, has_next, has_previous]

    ContextDetailResponse:
      type: object
      properties:
        success:
          type: boolean
          example: true
        data:
          $ref: '#/components/schemas/Context'
        timestamp:
          type: string
          format: date-time
        api_version:
          type: string
          example: "v1"
      required: [success, data, timestamp, api_version]

    ContextListResponse:
      type: object
      properties:
        success:
          type: boolean
          example: true
        data:
          type: array
          items:
            $ref: '#/components/schemas/Context'
        pagination:
          $ref: '#/components/schemas/PaginationMeta'
        timestamp:
          type: string
          format: date-time
        api_version:
          type: string
          example: "v1"
      required: [success, data, pagination, timestamp, api_version]

    BatchResponse:
      type: object
      properties:
        success:
          type: boolean
          example: true
        data:
          $ref: '#/components/schemas/BatchOperationResult'
        timestamp:
          type: string
          format: date-time
        api_version:
          type: string
          example: "v1"
      required: [success, data, timestamp, api_version]

    StatsResponse:
      type: object
      properties:
        context_stats:
          type: object
          properties:
            total_contexts:
              type: integer
            contexts_by_status:
              type: object
              additionalProperties:
                type: integer
            contexts_by_author:
              type: object
              additionalProperties:
                type: integer
            average_content_length:
              type: number
              format: float
        search_stats:
          type: object
          properties:
            total_searches:
              type: integer
            searches_by_type:
              type: object
              additionalProperties:
                type: integer
            average_response_time_ms:
              type: number
              format: float
            search_success_rate:
              type: number
              format: float
        system_stats:
          type: object
          properties:
            uptime_seconds:
              type: number
            memory_usage_mb:
              type: number
              format: float
            active_connections:
              type: integer
            cache_hit_rate:
              type: number
              format: float
            database_size_mb:
              type: number
              format: float

    SuccessResponse:
      type: object
      properties:
        success:
          type: boolean
          example: true
        message:
          type: string
          example: "Operation completed successfully"
        timestamp:
          type: string
          format: date-time
        api_version:
          type: string
          example: "v1"
      required: [success, message, timestamp, api_version]

    ErrorResponse:
      type: object
      properties:
        success:
          type: boolean
          example: false
        error:
          type: string
          description: Error message
        error_details:
          type: array
          items:
            type: object
            properties:
              field:
                type: string
                description: Field that caused the error
              message:
                type: string
                description: Detailed error message
              code:
                type: string
                description: Error code
        timestamp:
          type: string
          format: date-time
        request_id:
          type: string
          description: Unique request identifier
        api_version:
          type: string
          example: "v1"
      required: [success, error, timestamp, api_version]

  responses:
    Unauthorized:
      description: Authentication required
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          example:
            success: false
            error: "Authentication required"
            error_details:
              - message: "Valid API key or JWT token required"
            timestamp: "2024-01-15T10:30:00Z"
            api_version: "v1"

    ValidationError:
      description: Request validation failed
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          example:
            success: false
            error: "Request validation failed"
            error_details:
              - field: "path"
                message: "Path must start with /"
                code: "invalid_format"
              - field: "content"
                message: "Content cannot be empty"
                code: "required"
            timestamp: "2024-01-15T10:30:00Z"
            api_version: "v1"

    NotFound:
      description: Resource not found
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          example:
            success: false
            error: "Context not found"
            error_details:
              - message: "Context with ID 123 does not exist"
            timestamp: "2024-01-15T10:30:00Z"
            api_version: "v1"

    RateLimited:
      description: Rate limit exceeded
      headers:
        Retry-After:
          schema:
            type: integer
          description: Seconds to wait before retrying
        X-RateLimit-Limit:
          schema:
            type: integer
          description: Rate limit ceiling
        X-RateLimit-Remaining:
          schema:
            type: integer
          description: Remaining requests in current window
        X-RateLimit-Reset:
          schema:
            type: integer
          description: Unix timestamp when rate limit resets
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/ErrorResponse'
          example:
            success: false
            error: "Rate limit exceeded"
            error_details:
              - message: "Rate limit of 100 requests per minute exceeded"
            timestamp: "2024-01-15T10:30:00Z"
            retry_after: 45
            api_version: "v1"

webhooks:
  contextCreated:
    post:
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                event_type:
                  type: string
                  example: "context_created"
                data:
                  $ref: '#/components/schemas/Context'
                timestamp:
                  type: string
                  format: date-time
      responses:
        '200':
          description: Webhook received successfully

  contextUpdated:
    post:
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                event_type:
                  type: string
                  example: "context_updated"
                data:
                  $ref: '#/components/schemas/Context'
                timestamp:
                  type: string
                  format: date-time
      responses:
        '200':
          description: Webhook received successfully

  contextDeleted:
    post:
      requestBody:
        content:
          application/json:
            schema:
              type: object
              properties:
                event_type:
                  type: string
                  example: "context_deleted"
                data:
                  type: object
                  properties:
                    id:
                      type: integer
                    path:
                      type: string
                timestamp:
                  type: string
                  format: date-time
      responses:
        '200':
          description: Webhook received successfully