oai-swift/oAI/Providers/OpenRouterModels.swift

//
//  OpenRouterModels.swift
//  oAI
//
//  OpenRouter API request and response models
//
// SPDX-License-Identifier: AGPL-3.0-or-later
// Copyright (C) 2026 Rune Olsen
//
// This file is part of oAI.
//
// oAI is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// oAI is distributed in the hope that it will be useful, but WITHOUT
// ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
// or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General
// Public License for more details.
//
// You should have received a copy of the GNU Affero General Public
// License along with oAI. If not, see <https://www.gnu.org/licenses/>.


import Foundation

// MARK: - API Request

struct OpenRouterChatRequest: Codable {
    let model: String
    let messages: [APIMessage]
    var stream: Bool
    let maxTokens: Int?
    let temperature: Double?
    let topP: Double?
    let tools: [Tool]?
    let toolChoice: String?
    let modalities: [String]?
    
    struct APIMessage: Codable {
        let role: String
        let content: MessageContent
        
        enum MessageContent: Codable {
            case string(String)
            case array([ContentItem])
            
            init(from decoder: Decoder) throws {
                let container = try decoder.singleValueContainer()
                if let str = try? container.decode(String.self) {
                    self = .string(str)
                } else if let arr = try? container.decode([ContentItem].self) {
                    self = .array(arr)
                } else {
                    throw DecodingError.dataCorruptedError(in: container, debugDescription: "Invalid content")
                }
            }
            
            func encode(to encoder: Encoder) throws {
                var container = encoder.singleValueContainer()
                switch self {
                case .string(let str):
                    try container.encode(str)
                case .array(let arr):
                    try container.encode(arr)
                }
            }
        }
        
        enum ContentItem: Codable {
            case text(String)
            case image(ImageContent)

            struct TextContent: Codable {
                let type: String // "text"
                let text: String
            }

            struct ImageContent: Codable {
                let type: String // "image_url"
                let imageUrl: ImageURL

                struct ImageURL: Codable {
                    let url: String
                }

                enum CodingKeys: String, CodingKey {
                    case type
                    case imageUrl = "image_url"
                }
            }

            init(from decoder: Decoder) throws {
                let container = try decoder.singleValueContainer()
                if let textContent = try? container.decode(TextContent.self), textContent.type == "text" {
                    self = .text(textContent.text)
                } else if let image = try? container.decode(ImageContent.self) {
                    self = .image(image)
                } else if let str = try? container.decode(String.self) {
                    self = .text(str)
                } else {
                    throw DecodingError.dataCorruptedError(in: container, debugDescription: "Invalid content item")
                }
            }

            func encode(to encoder: Encoder) throws {
                var container = encoder.singleValueContainer()
                switch self {
                case .text(let text):
                    try container.encode(TextContent(type: "text", text: text))
                case .image(let image):
                    try container.encode(image)
                }
            }
        }
    }
    
    enum CodingKeys: String, CodingKey {
        case model
        case messages
        case stream
        case maxTokens = "max_tokens"
        case temperature
        case topP = "top_p"
        case tools
        case toolChoice = "tool_choice"
        case modalities
    }
}

// MARK: - API Response

struct OpenRouterChatResponse: Codable {
    let id: String
    let model: String
    let choices: [Choice]
    let usage: Usage?
    let created: Int
    
    struct Choice: Codable {
        let index: Int
        let message: MessageContent
        let finishReason: String?

        struct MessageContent: Codable {
            let role: String
            let content: String?
            let toolCalls: [APIToolCall]?
            let images: [ImageOutput]?

            enum CodingKeys: String, CodingKey {
                case role
                case content
                case toolCalls = "tool_calls"
                case images
            }
        }

        enum CodingKeys: String, CodingKey {
            case index
            case message
            case finishReason = "finish_reason"
        }
    }

    struct ImageOutput: Codable {
        let imageUrl: ImageURL

        struct ImageURL: Codable {
            let url: String
        }

        enum CodingKeys: String, CodingKey {
            case imageUrl = "image_url"
        }
    }
    
    struct Usage: Codable {
        let promptTokens: Int
        let completionTokens: Int
        let totalTokens: Int
        
        enum CodingKeys: String, CodingKey {
            case promptTokens = "prompt_tokens"
            case completionTokens = "completion_tokens"
            case totalTokens = "total_tokens"
        }
    }
}

// MARK: - Streaming Response

struct OpenRouterStreamChunk: Codable {
    let id: String
    let model: String
    let choices: [StreamChoice]
    let usage: OpenRouterChatResponse.Usage?
    
    struct StreamChoice: Codable {
        let index: Int
        let delta: Delta
        let finishReason: String?

        struct Delta: Codable {
            let role: String?
            let content: String?
            let images: [OpenRouterChatResponse.ImageOutput]?
        }

        enum CodingKeys: String, CodingKey {
            case index
            case delta
            case finishReason = "finish_reason"
        }
    }
}

// MARK: - Models List

struct OpenRouterModelsResponse: Codable {
    let data: [ModelData]
    
    struct ModelData: Codable {
        let id: String
        let name: String
        let description: String?
        let contextLength: Int
        let pricing: PricingData
        let architecture: Architecture?
        let supportedParameters: [String]?
        let outputModalities: [String]?

        struct PricingData: Codable {
            let prompt: String
            let completion: String
        }

        struct Architecture: Codable {
            let modality: String?
            let tokenizer: String?
            let instructType: String?

            enum CodingKeys: String, CodingKey {
                case modality
                case tokenizer
                case instructType = "instruct_type"
            }
        }

        enum CodingKeys: String, CodingKey {
            case id
            case name
            case description
            case contextLength = "context_length"
            case pricing
            case architecture
            case supportedParameters = "supported_parameters"
            case outputModalities = "output_modalities"
        }
    }
}

// MARK: - Credits Response

struct OpenRouterCreditsResponse: Codable {
    let data: CreditsData

    struct CreditsData: Codable {
        let totalCredits: Double?
        let totalUsage: Double?

        enum CodingKeys: String, CodingKey {
            case totalCredits = "total_credits"
            case totalUsage = "total_usage"
        }
    }
}

// MARK: - Tool Call Models

struct APIToolCall: Codable {
    let id: String
    let type: String
    let function: FunctionCall

    struct FunctionCall: Codable {
        let name: String
        let arguments: String
    }
}

/// Message shape for encoding assistant messages that contain tool calls
struct AssistantToolCallMessage: Encodable {
    let role: String
    let content: String?
    let toolCalls: [APIToolCall]

    enum CodingKeys: String, CodingKey {
        case role
        case content
        case toolCalls = "tool_calls"
    }
}

/// Message shape for encoding tool result messages back to the API
struct ToolResultMessage: Encodable {
    let role: String // "tool"
    let toolCallId: String
    let name: String
    let content: String

    enum CodingKeys: String, CodingKey {
        case role
        case toolCallId = "tool_call_id"
        case name
        case content
    }
}

// MARK: - Error Response

struct OpenRouterErrorResponse: Codable {
    let error: ErrorDetail
    
    struct ErrorDetail: Codable {
        let message: String
        let type: String?
        let code: String?
    }
}