use serde::{Deserialize, Serialize};

use crate::v1::{common, constants, tool};

// -----------------------------------------------------------------------------
// Definitions

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct ChatMessage {
    pub role: ChatMessageRole,
    pub content: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tool_calls: Option<Vec<tool::ToolCall>>,
    /// Tool call ID, required when role is Tool.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tool_call_id: Option<String>,
    /// Function name, used when role is Tool.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
}
impl ChatMessage {
    pub fn new_system_message(content: &str) -> Self {
        Self {
            role: ChatMessageRole::System,
            content: content.to_string(),
            tool_calls: None,
            tool_call_id: None,
            name: None,
        }
    }

    pub fn new_assistant_message(content: &str, tool_calls: Option<Vec<tool::ToolCall>>) -> Self {
        Self {
            role: ChatMessageRole::Assistant,
            content: content.to_string(),
            tool_calls,
            tool_call_id: None,
            name: None,
        }
    }

    pub fn new_user_message(content: &str) -> Self {
        Self {
            role: ChatMessageRole::User,
            content: content.to_string(),
            tool_calls: None,
            tool_call_id: None,
            name: None,
        }
    }

    pub fn new_tool_message(content: &str, tool_call_id: &str, name: Option<&str>) -> Self {
        Self {
            role: ChatMessageRole::Tool,
            content: content.to_string(),
            tool_calls: None,
            tool_call_id: Some(tool_call_id.to_string()),
            name: name.map(|n| n.to_string()),
        }
    }
}

/// See the [Mistral AI API documentation](https://docs.mistral.ai/capabilities/completion/#chat-messages) for more information.
#[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
pub enum ChatMessageRole {
    #[serde(rename = "system")]
    System,
    #[serde(rename = "assistant")]
    Assistant,
    #[serde(rename = "user")]
    User,
    #[serde(rename = "tool")]
    Tool,
}

/// The format that the model must output.
#[derive(Clone, Debug, Serialize, Deserialize)]
pub struct ResponseFormat {
    #[serde(rename = "type")]
    pub type_: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub json_schema: Option<serde_json::Value>,
}
impl ResponseFormat {
    pub fn text() -> Self {
        Self {
            type_: "text".to_string(),
            json_schema: None,
        }
    }

    pub fn json_object() -> Self {
        Self {
            type_: "json_object".to_string(),
            json_schema: None,
        }
    }

    pub fn json_schema(schema: serde_json::Value) -> Self {
        Self {
            type_: "json_schema".to_string(),
            json_schema: Some(schema),
        }
    }
}

// -----------------------------------------------------------------------------
// Request

/// The parameters for the chat request.
#[derive(Clone, Debug)]
pub struct ChatParams {
    pub max_tokens: Option<u32>,
    pub min_tokens: Option<u32>,
    pub random_seed: Option<u32>,
    pub response_format: Option<ResponseFormat>,
    pub safe_prompt: bool,
    pub temperature: Option<f32>,
    pub tool_choice: Option<tool::ToolChoice>,
    pub tools: Option<Vec<tool::Tool>>,
    pub top_p: Option<f32>,
    pub stop: Option<Vec<String>>,
    pub n: Option<u32>,
    pub frequency_penalty: Option<f32>,
    pub presence_penalty: Option<f32>,
    pub parallel_tool_calls: Option<bool>,
    /// For reasoning models (Magistral). "high" or "none".
    pub reasoning_effort: Option<String>,
}
impl Default for ChatParams {
    fn default() -> Self {
        Self {
            max_tokens: None,
            min_tokens: None,
            random_seed: None,
            safe_prompt: false,
            response_format: None,
            temperature: None,
            tool_choice: None,
            tools: None,
            top_p: None,
            stop: None,
            n: None,
            frequency_penalty: None,
            presence_penalty: None,
            parallel_tool_calls: None,
            reasoning_effort: None,
        }
    }
}

#[derive(Debug, Serialize, Deserialize)]
pub struct ChatRequest {
    pub model: constants::Model,
    pub messages: Vec<ChatMessage>,
    pub stream: bool,

    #[serde(skip_serializing_if = "Option::is_none")]
    pub max_tokens: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub min_tokens: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub random_seed: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub response_format: Option<ResponseFormat>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub safe_prompt: Option<bool>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub temperature: Option<f32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tool_choice: Option<tool::ToolChoice>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub tools: Option<Vec<tool::Tool>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub top_p: Option<f32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub stop: Option<Vec<String>>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub n: Option<u32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub frequency_penalty: Option<f32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub presence_penalty: Option<f32>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub parallel_tool_calls: Option<bool>,
    #[serde(skip_serializing_if = "Option::is_none")]
    pub reasoning_effort: Option<String>,
}
impl ChatRequest {
    pub fn new(
        model: constants::Model,
        messages: Vec<ChatMessage>,
        stream: bool,
        options: Option<ChatParams>,
    ) -> Self {
        let opts = options.unwrap_or_default();
        let safe_prompt = if opts.safe_prompt { Some(true) } else { None };

        Self {
            model,
            messages,
            stream,
            max_tokens: opts.max_tokens,
            min_tokens: opts.min_tokens,
            random_seed: opts.random_seed,
            safe_prompt,
            temperature: opts.temperature,
            tool_choice: opts.tool_choice,
            tools: opts.tools,
            top_p: opts.top_p,
            response_format: opts.response_format,
            stop: opts.stop,
            n: opts.n,
            frequency_penalty: opts.frequency_penalty,
            presence_penalty: opts.presence_penalty,
            parallel_tool_calls: opts.parallel_tool_calls,
            reasoning_effort: opts.reasoning_effort,
        }
    }
}

// -----------------------------------------------------------------------------
// Response

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct ChatResponse {
    pub id: String,
    pub object: String,
    /// Unix timestamp (in seconds).
    pub created: u64,
    pub model: constants::Model,
    pub choices: Vec<ChatResponseChoice>,
    pub usage: common::ResponseUsage,
}

#[derive(Clone, Debug, Deserialize, Serialize)]
pub struct ChatResponseChoice {
    pub index: u32,
    pub message: ChatMessage,
    pub finish_reason: ChatResponseChoiceFinishReason,
}

#[derive(Clone, Debug, Eq, PartialEq, Deserialize, Serialize)]
pub enum ChatResponseChoiceFinishReason {
    #[serde(rename = "stop")]
    Stop,
    #[serde(rename = "length")]
    Length,
    #[serde(rename = "tool_calls")]
    ToolCalls,
    #[serde(rename = "model_length")]
    ModelLength,
    #[serde(rename = "error")]
    Error,
}