liter-llm 1.3.0

use serde::{Deserialize, Serialize};

// ─── Messages ────────────────────────────────────────────────────────────────

/// A chat message in a conversation.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(tag = "role")]
pub enum Message {
    #[serde(rename = "system")]
    System(SystemMessage),
    #[serde(rename = "user")]
    User(UserMessage),
    #[serde(rename = "assistant")]
    Assistant(AssistantMessage),
    #[serde(rename = "tool")]
    Tool(ToolMessage),
    #[serde(rename = "developer")]
    Developer(DeveloperMessage),
    /// Deprecated legacy function-role message; retained for API compatibility.
    #[serde(rename = "function")]
    Function(FunctionMessage),
}

impl Default for Message {
    fn default() -> Self {
        Self::Assistant(AssistantMessage::default())
    }
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct SystemMessage {
    pub content: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct UserMessage {
    pub content: UserContent,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(untagged)]
pub enum UserContent {
    Text(String),
    Parts(Vec<ContentPart>),
}

impl Default for UserContent {
    fn default() -> Self {
        Self::Text(String::new())
    }
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(tag = "type")]
pub enum ContentPart {
    #[serde(rename = "text")]
    Text { text: String },
    #[serde(rename = "image_url")]
    ImageUrl { image_url: ImageUrl },
    #[serde(rename = "document")]
    Document { document: DocumentContent },
    #[serde(rename = "input_audio")]
    InputAudio { input_audio: AudioContent },
}

impl Default for ContentPart {
    fn default() -> Self {
        Self::Text { text: String::new() }
    }
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ImageUrl {
    pub url: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub detail: Option<ImageDetail>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum ImageDetail {
    Low,
    High,
    Auto,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct DocumentContent {
    /// Base64-encoded document data or URL.
    pub data: String,
    /// MIME type (e.g., "application/pdf", "text/csv").
    pub media_type: String,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct AudioContent {
    /// Base64-encoded audio data.
    pub data: String,
    /// Audio format (e.g., "wav", "mp3", "ogg").
    pub format: String,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct AssistantMessage {
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub content: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tool_calls: Option<Vec<ToolCall>>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub refusal: Option<String>,
    /// Deprecated legacy function_call field; retained for API compatibility.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub function_call: Option<FunctionCall>,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct ToolMessage {
    pub content: String,
    pub tool_call_id: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct DeveloperMessage {
    pub content: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
}

/// Deprecated legacy function-role message body.
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct FunctionMessage {
    pub content: String,
    pub name: String,
}

// ─── Tools ───────────────────────────────────────────────────────────────────

/// The type discriminator for tool/tool-call objects.
///
/// Per the OpenAI spec this is always `"function"`. Using an enum enforces
/// that constraint at the type level and rejects any other value on
/// deserialization.
#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
pub enum ToolType {
    #[default]
    #[serde(rename = "function")]
    Function,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ChatCompletionTool {
    #[serde(rename = "type")]
    pub tool_type: ToolType,
    pub function: FunctionDefinition,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct FunctionDefinition {
    pub name: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub parameters: Option<serde_json::Value>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub strict: Option<bool>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct ToolCall {
    pub id: String,
    #[serde(rename = "type")]
    pub call_type: ToolType,
    pub function: FunctionCall,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct FunctionCall {
    pub name: String,
    pub arguments: String,
}

// ─── Tool Choice ─────────────────────────────────────────────────────────────

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(untagged)]
pub enum ToolChoice {
    Mode(ToolChoiceMode),
    Specific(SpecificToolChoice),
}

impl Default for ToolChoice {
    fn default() -> Self {
        Self::Mode(ToolChoiceMode::default())
    }
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum ToolChoiceMode {
    #[default]
    Auto,
    Required,
    None,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct SpecificToolChoice {
    #[serde(rename = "type")]
    pub choice_type: ToolType,
    pub function: SpecificFunction,
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct SpecificFunction {
    pub name: String,
}

// ─── Response Format ─────────────────────────────────────────────────────────

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(tag = "type")]
pub enum ResponseFormat {
    #[default]
    #[serde(rename = "text")]
    Text,
    #[serde(rename = "json_object")]
    JsonObject,
    #[serde(rename = "json_schema")]
    JsonSchema { json_schema: JsonSchemaFormat },
}

#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct JsonSchemaFormat {
    pub name: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
    pub schema: serde_json::Value,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub strict: Option<bool>,
}

// ─── Usage ───────────────────────────────────────────────────────────────────

#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
pub struct Usage {
    /// Prompt tokens used. Defaults to 0 when absent (some providers omit this).
    #[serde(default)]
    pub prompt_tokens: u64,
    /// Completion tokens used. Defaults to 0 when absent (e.g. embedding responses).
    #[serde(default)]
    pub completion_tokens: u64,
    /// Total tokens used. Defaults to 0 when absent (some providers omit this).
    #[serde(default)]
    pub total_tokens: u64,
}

// ─── Stop Sequence ───────────────────────────────────────────────────────────

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
#[serde(untagged)]
pub enum StopSequence {
    Single(String),
    Multiple(Vec<String>),
}

impl Default for StopSequence {
    fn default() -> Self {
        Self::Single(String::new())
    }
}