import Foundation

// ─────────────────────────────────────────────────────────────
// JSON Schema Response API Models
// OpenAI Compatible Format
// ─────────────────────────────────────────────────────────────

/// Response format specification
public enum ResponseFormat: Codable {
    case text
    case jsonObject
    case jsonSchema(JSONSchemaDefinition)
    
    private enum CodingKeys: String, CodingKey {
        case type
        case jsonSchema = "json_schema"
    }
    
    public init(from decoder: Decoder) throws {
        let container = try decoder.container(keyedBy: CodingKeys.self)
        let type = try container.decode(String.self, forKey: .type)
        
        switch type {
        case "text":
            self = .text
        case "json_object":
            self = .jsonObject
        case "json_schema":
            let schema = try container.decode(JSONSchemaDefinition.self, forKey: .jsonSchema)
            self = .jsonSchema(schema)
        default:
            throw DecodingError.dataCorruptedError(
                forKey: .type,
                in: container,
                debugDescription: "Unknown response format type: \(type)"
            )
        }
    }
    
    public func encode(to encoder: Encoder) throws {
        var container = encoder.container(keyedBy: CodingKeys.self)
        
        switch self {
        case .text:
            try container.encode("text", forKey: .type)
        case .jsonObject:
            try container.encode("json_object", forKey: .type)
        case .jsonSchema(let schema):
            try container.encode("json_schema", forKey: .type)
            try container.encode(schema, forKey: .jsonSchema)
        }
    }
}

/// JSON Schema definition
public struct JSONSchemaDefinition: Codable {
    public let name: String
    public let description: String?
    public let schema: JSONSchema
    public let strict: Bool?
    
    public init(
        name: String,
        description: String? = nil,
        schema: JSONSchema,
        strict: Bool? = nil
    ) {
        self.name = name
        self.description = description
        self.schema = schema
        self.strict = strict
    }
}

/// JSON Schema
public struct JSONSchema: Codable {
    public let type: String
    public let properties: [String: SchemaProperty]?
    public let required: [String]?
    public let additionalProperties: Bool?
    
    public init(
        type: String,
        properties: [String: SchemaProperty]? = nil,
        required: [String]? = nil,
        additionalProperties: Bool? = false
    ) {
        self.type = type
        self.properties = properties
        self.required = required
        self.additionalProperties = additionalProperties
    }
}

/// Schema property
public struct SchemaProperty: Codable {
    public let type: String
    public let description: String?
    public let `enum`: [String]?
    public let properties: [String: SchemaProperty]?
    public let required: [String]?
    
    public init(
        type: String,
        description: String? = nil,
        enum: [String]? = nil,
        properties: [String: SchemaProperty]? = nil,
        required: [String]? = nil
    ) {
        self.type = type
        self.description = description
        self.enum = `enum`
        self.properties = properties
        self.required = required
    }
}