use crate::apis::anthropic::MessagesRequest;
use crate::apis::openai::ChatCompletionsRequest;
use crate::clients::endpoints::SupportedAPIs;

use serde_json::Value;
use std::collections::HashMap;
use std::error::Error;
use std::fmt;
#[derive(Clone)]
pub enum ProviderRequestType {
    ChatCompletionsRequest(ChatCompletionsRequest),
    MessagesRequest(MessagesRequest),
    //add more request types here
}
pub trait ProviderRequest: Send + Sync {
    /// Extract the model name from the request
    fn model(&self) -> &str;

    /// Set the model name for the request
    fn set_model(&mut self, model: String);

    /// Check if this is a streaming request
    fn is_streaming(&self) -> bool;

    /// Extract text content from messages for token counting
    fn extract_messages_text(&self) -> String;

    /// Extract the user message for tracing/logging purposes
    fn get_recent_user_message(&self) -> Option<String>;

    /// Convert the request to bytes for transmission
    fn to_bytes(&self) -> Result<Vec<u8>, ProviderRequestError>;

    fn metadata(&self) -> &Option<HashMap<String, Value>>;

    /// Remove a metadata key from the request and return true if the key was present
    fn remove_metadata_key(&mut self, key: &str) -> bool;
}

impl ProviderRequest for ProviderRequestType {
    fn model(&self) -> &str {
        match self {
            Self::ChatCompletionsRequest(r) => r.model(),
            Self::MessagesRequest(r) => r.model(),
        }
    }

    fn set_model(&mut self, model: String) {
        match self {
            Self::ChatCompletionsRequest(r) => r.set_model(model),
            Self::MessagesRequest(r) => r.set_model(model),
        }
    }

    fn is_streaming(&self) -> bool {
        match self {
            Self::ChatCompletionsRequest(r) => r.is_streaming(),
            Self::MessagesRequest(r) => r.is_streaming(),
        }
    }

    fn extract_messages_text(&self) -> String {
        match self {
            Self::ChatCompletionsRequest(r) => r.extract_messages_text(),
            Self::MessagesRequest(r) => r.extract_messages_text(),
        }
    }

    fn get_recent_user_message(&self) -> Option<String> {
        match self {
            Self::ChatCompletionsRequest(r) => r.get_recent_user_message(),
            Self::MessagesRequest(r) => r.get_recent_user_message(),
        }
    }

    fn to_bytes(&self) -> Result<Vec<u8>, ProviderRequestError> {
        match self {
            Self::ChatCompletionsRequest(r) => r.to_bytes(),
            Self::MessagesRequest(r) => r.to_bytes(),
        }
    }

    fn metadata(&self) -> &Option<HashMap<String, Value>> {
        match self {
            Self::ChatCompletionsRequest(r) => r.metadata(),
            Self::MessagesRequest(r) => r.metadata(),
        }
    }

    fn remove_metadata_key(&mut self, key: &str) -> bool {
        match self {
            Self::ChatCompletionsRequest(r) => r.remove_metadata_key(key),
            Self::MessagesRequest(r) => r.remove_metadata_key(key),
        }
    }
}

/// Parse the client API from a byte slice.
impl TryFrom<(&[u8], &SupportedAPIs)> for ProviderRequestType {
    type Error = std::io::Error;

    fn try_from((bytes, client_api): (&[u8], &SupportedAPIs)) -> Result<Self, Self::Error> {
        // Use SupportedApi to determine the appropriate request type
        match client_api {
            SupportedAPIs::OpenAIChatCompletions(_) => {
                let chat_completion_request: ChatCompletionsRequest =
                    ChatCompletionsRequest::try_from(bytes)
                        .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))?;
                Ok(ProviderRequestType::ChatCompletionsRequest(
                    chat_completion_request,
                ))
            }
            SupportedAPIs::AnthropicMessagesAPI(_) => {
                let messages_request: MessagesRequest = MessagesRequest::try_from(bytes)
                    .map_err(|e| std::io::Error::new(std::io::ErrorKind::InvalidData, e))?;
                Ok(ProviderRequestType::MessagesRequest(messages_request))
            }
        }
    }
}

/// Conversion from one ProviderRequestType to a different ProviderRequestType (SupportedAPIs)
impl TryFrom<(ProviderRequestType, &SupportedAPIs)> for ProviderRequestType {
    type Error = ProviderRequestError;

    fn try_from(
        (request, upstream_api): (ProviderRequestType, &SupportedAPIs),
    ) -> Result<Self, Self::Error> {
        match (request, upstream_api) {
            // Same API - no conversion needed, just clone the reference
            (
                ProviderRequestType::ChatCompletionsRequest(chat_req),
                SupportedAPIs::OpenAIChatCompletions(_),
            ) => Ok(ProviderRequestType::ChatCompletionsRequest(chat_req)),
            (
                ProviderRequestType::MessagesRequest(messages_req),
                SupportedAPIs::AnthropicMessagesAPI(_),
            ) => Ok(ProviderRequestType::MessagesRequest(messages_req)),

            // Cross-API conversion - cloning is necessary for transformation
            (
                ProviderRequestType::ChatCompletionsRequest(chat_req),
                SupportedAPIs::AnthropicMessagesAPI(_),
            ) => {
                let messages_req =
                    MessagesRequest::try_from(chat_req).map_err(|e| ProviderRequestError {
                        message: format!(
                            "Failed to convert ChatCompletionsRequest to MessagesRequest: {}",
                            e
                        ),
                        source: Some(Box::new(e)),
                    })?;
                Ok(ProviderRequestType::MessagesRequest(messages_req))
            }

            (
                ProviderRequestType::MessagesRequest(messages_req),
                SupportedAPIs::OpenAIChatCompletions(_),
            ) => {
                let chat_req = ChatCompletionsRequest::try_from(messages_req).map_err(|e| {
                    ProviderRequestError {
                        message: format!(
                            "Failed to convert MessagesRequest to ChatCompletionsRequest: {}",
                            e
                        ),
                        source: Some(Box::new(e)),
                    }
                })?;
                Ok(ProviderRequestType::ChatCompletionsRequest(chat_req))
            }
        }
    }
}

/// Error types for provider operations
#[derive(Debug)]
pub struct ProviderRequestError {
    pub message: String,
    pub source: Option<Box<dyn Error + Send + Sync>>,
}

impl fmt::Display for ProviderRequestError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "Provider request error: {}", self.message)
    }
}

impl Error for ProviderRequestError {
    fn source(&self) -> Option<&(dyn Error + 'static)> {
        self.source
            .as_ref()
            .map(|e| e.as_ref() as &(dyn Error + 'static))
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::apis::anthropic::AnthropicApi::Messages;
    use crate::apis::anthropic::MessagesRequest as AnthropicMessagesRequest;
    use crate::apis::openai::ChatCompletionsRequest;
    use crate::apis::openai::OpenAIApi::ChatCompletions;
    use crate::clients::endpoints::SupportedAPIs;
    use crate::clients::transformer::ExtractText;
    use serde_json::json;

    #[test]
    fn test_openai_request_from_bytes() {
        let req = json!({
            "model": "gpt-4",
            "messages": [
                {"role": "system", "content": "You are a helpful assistant"},
                {"role": "user", "content": "Hello!"}
            ]
        });
        let bytes = serde_json::to_vec(&req).unwrap();
        let api = SupportedAPIs::OpenAIChatCompletions(ChatCompletions);
        let result = ProviderRequestType::try_from((bytes.as_slice(), &api));
        assert!(result.is_ok());
        match result.unwrap() {
            ProviderRequestType::ChatCompletionsRequest(r) => {
                assert_eq!(r.model, "gpt-4");
                assert_eq!(r.messages.len(), 2);
            }
            _ => panic!("Expected ChatCompletionsRequest variant"),
        }
    }

    #[test]
    fn test_anthropic_request_from_bytes_with_endpoint() {
        let req = json!({
            "model": "claude-3-sonnet",
            "system": "You are a helpful assistant",
            "max_tokens": 100,
            "messages": [
                {"role": "user", "content": "Hello!"}
            ]
        });
        let bytes = serde_json::to_vec(&req).unwrap();
        let endpoint = SupportedAPIs::AnthropicMessagesAPI(Messages);
        let result = ProviderRequestType::try_from((bytes.as_slice(), &endpoint));
        assert!(result.is_ok());
        match result.unwrap() {
            ProviderRequestType::MessagesRequest(r) => {
                assert_eq!(r.model, "claude-3-sonnet");
                assert_eq!(r.messages.len(), 1);
            }
            _ => panic!("Expected MessagesRequest variant"),
        }
    }

    #[test]
    fn test_openai_request_from_bytes_with_endpoint() {
        let req = json!({
            "model": "gpt-4",
            "messages": [
                {"role": "system", "content": "You are a helpful assistant"},
                {"role": "user", "content": "Hello!"}
            ]
        });
        let bytes = serde_json::to_vec(&req).unwrap();
        let endpoint = SupportedAPIs::OpenAIChatCompletions(ChatCompletions);
        let result = ProviderRequestType::try_from((bytes.as_slice(), &endpoint));
        assert!(result.is_ok());
        match result.unwrap() {
            ProviderRequestType::ChatCompletionsRequest(r) => {
                assert_eq!(r.model, "gpt-4");
                assert_eq!(r.messages.len(), 2);
            }
            _ => panic!("Expected ChatCompletionsRequest variant"),
        }
    }

    #[test]
    fn test_anthropic_request_from_bytes_wrong_endpoint() {
        let req = json!({
            "model": "claude-3-sonnet",
            "system": "You are a helpful assistant",
            "messages": [
                {"role": "user", "content": "Hello!"}
            ]
        });
        let bytes = serde_json::to_vec(&req).unwrap();
        // Intentionally use OpenAI endpoint for Anthropic payload
        let endpoint = SupportedAPIs::OpenAIChatCompletions(ChatCompletions);
        let result = ProviderRequestType::try_from((bytes.as_slice(), &endpoint));
        // Should parse as ChatCompletionsRequest, not error
        assert!(result.is_ok());
        match result.unwrap() {
            ProviderRequestType::ChatCompletionsRequest(r) => {
                assert_eq!(r.model, "claude-3-sonnet");
                assert_eq!(r.messages.len(), 1);
            }
            _ => panic!("Expected ChatCompletionsRequest variant"),
        }
    }

    #[test]
    fn test_v1_messages_to_v1_chat_completions_roundtrip() {
        let anthropic_req = AnthropicMessagesRequest {
            model: "claude-3-sonnet".to_string(),
            system: Some(crate::apis::anthropic::MessagesSystemPrompt::Single(
                "You are a helpful assistant".to_string(),
            )),
            messages: vec![crate::apis::anthropic::MessagesMessage {
                role: crate::apis::anthropic::MessagesRole::User,
                content: crate::apis::anthropic::MessagesMessageContent::Single(
                    "Hello!".to_string(),
                ),
            }],
            max_tokens: 128,
            container: None,
            mcp_servers: None,
            service_tier: None,
            thinking: None,
            temperature: Some(0.7),
            top_p: Some(1.0),
            top_k: None,
            stream: Some(false),
            stop_sequences: Some(vec!["\n".to_string()]),
            tools: None,
            tool_choice: None,
            metadata: None,
        };

        let openai_req = ChatCompletionsRequest::try_from(anthropic_req.clone())
            .expect("Anthropic->OpenAI conversion failed");
        let anthropic_req2 = AnthropicMessagesRequest::try_from(openai_req)
            .expect("OpenAI->Anthropic conversion failed");

        assert_eq!(anthropic_req.model, anthropic_req2.model);
        // Compare system prompt text if present
        assert_eq!(
            anthropic_req.system.as_ref().and_then(|s| match s {
                crate::apis::anthropic::MessagesSystemPrompt::Single(t) => Some(t),
                _ => None,
            }),
            anthropic_req2.system.as_ref().and_then(|s| match s {
                crate::apis::anthropic::MessagesSystemPrompt::Single(t) => Some(t),
                _ => None,
            })
        );
        assert_eq!(
            anthropic_req.messages[0].role,
            anthropic_req2.messages[0].role
        );
        // Compare message content text if present
        assert_eq!(
            anthropic_req.messages[0].content.extract_text(),
            anthropic_req2.messages[0].content.extract_text()
        );
        assert_eq!(anthropic_req.max_tokens, anthropic_req2.max_tokens);
    }

    #[test]
    fn test_v1_chat_completions_to_v1_messages_roundtrip() {
        use crate::apis::anthropic::MessagesRequest as AnthropicMessagesRequest;
        use crate::apis::openai::{ChatCompletionsRequest, Message, MessageContent, Role};

        let openai_req = ChatCompletionsRequest {
            model: "gpt-4".to_string(),
            messages: vec![
                Message {
                    role: Role::System,
                    content: MessageContent::Text("You are a helpful assistant".to_string()),
                    name: None,
                    tool_calls: None,
                    tool_call_id: None,
                },
                Message {
                    role: Role::User,
                    content: MessageContent::Text("Hello!".to_string()),
                    name: None,
                    tool_calls: None,
                    tool_call_id: None,
                },
            ],
            temperature: Some(0.7),
            top_p: Some(1.0),
            max_tokens: Some(128),
            stream: Some(false),
            stop: Some(vec!["\n".to_string()]),
            tools: None,
            tool_choice: None,
            parallel_tool_calls: None,
            ..Default::default()
        };

        let anthropic_req = AnthropicMessagesRequest::try_from(openai_req.clone())
            .expect("OpenAI->Anthropic conversion failed");
        let openai_req2 = ChatCompletionsRequest::try_from(anthropic_req)
            .expect("Anthropic->OpenAI conversion failed");

        assert_eq!(openai_req.model, openai_req2.model);
        assert_eq!(openai_req.messages[0].role, openai_req2.messages[0].role);
        assert_eq!(
            openai_req.messages[0].content.extract_text(),
            openai_req2.messages[0].content.extract_text()
        );
        // After roundtrip, deprecated max_tokens should be converted to max_completion_tokens
        let original_max_tokens = openai_req.max_completion_tokens.or(openai_req.max_tokens);
        let roundtrip_max_tokens = openai_req2.max_completion_tokens.or(openai_req2.max_tokens);
        assert_eq!(original_max_tokens, roundtrip_max_tokens);
    }
}