gigi-cli 1.0.1

use anyhow::{Context, Result};
use async_trait::async_trait;
use reqwest::Client;
use serde::{Deserialize, Serialize};

use super::provider::ModelProvider;
use super::types::*;

// =============================================================================
// Anthropic Claude Provider
// =============================================================================

/// Provider for the Anthropic Messages API (Claude models).
pub struct AnthropicProvider {
    client: Client,
    api_key: String,
    model: String,
    base_url: String,
}

impl AnthropicProvider {
    pub fn new(api_key: String, model: Option<String>, base_url: Option<String>) -> Self {
        Self {
            client: Client::new(),
            api_key,
            model: model.unwrap_or_else(|| "claude-sonnet-4-20250514".to_string()),
            base_url: base_url.unwrap_or_else(|| "https://api.anthropic.com".to_string()),
        }
    }

    /// Build the Anthropic-specific request body.
    fn build_request_body(&self, request: &CompletionRequest) -> AnthropicRequest {
        let messages: Vec<AnthropicMessage> = request
            .messages
            .iter()
            .map(|msg| AnthropicMessage {
                role: match msg.role {
                    Role::User => "user".to_string(),
                    Role::Assistant => "assistant".to_string(),
                    Role::System => "user".to_string(), // System role handled separately
                },
                content: msg
                    .content
                    .iter()
                    .map(|block| match block {
                        ContentBlock::Text { text } => AnthropicContent::Text {
                            text: text.clone(),
                        },
                        ContentBlock::ToolUse { id, name, input } => AnthropicContent::ToolUse {
                            id: id.clone(),
                            name: name.clone(),
                            input: input.clone(),
                        },
                        ContentBlock::ToolResult {
                            tool_use_id,
                            content,
                            is_error,
                        } => AnthropicContent::ToolResult {
                            tool_use_id: tool_use_id.clone(),
                            content: content.clone(),
                            is_error: *is_error,
                        },
                    })
                    .collect(),
            })
            .collect();

        let tools: Vec<AnthropicTool> = request
            .tools
            .iter()
            .map(|t| AnthropicTool {
                name: t.name.clone(),
                description: t.description.clone(),
                input_schema: t.input_schema.clone(),
            })
            .collect();

        AnthropicRequest {
            model: self.model.clone(),
            max_tokens: request.max_tokens,
            system: if request.system.is_empty() {
                None
            } else {
                Some(request.system.clone())
            },
            messages,
            tools: if tools.is_empty() { None } else { Some(tools) },
        }
    }
}

#[async_trait]
impl ModelProvider for AnthropicProvider {
    async fn complete(&self, request: CompletionRequest) -> Result<CompletionResponse> {
        let url = format!("{}/v1/messages", self.base_url);
        let body = self.build_request_body(&request);

        let response = self
            .client
            .post(&url)
            .header("x-api-key", &self.api_key)
            .header("anthropic-version", "2023-06-01")
            .header("content-type", "application/json")
            .json(&body)
            .send()
            .await
            .context("Failed to send request to Anthropic API")?;

        if !response.status().is_success() {
            let status = response.status();
            let error_text = response.text().await.unwrap_or_default();
            anyhow::bail!("Anthropic API error ({}): {}", status, error_text);
        }

        let api_response: AnthropicResponse = response
            .json()
            .await
            .context("Failed to parse Anthropic API response")?;

        // Convert Anthropic response to our internal types
        let content: Vec<ContentBlock> = api_response
            .content
            .into_iter()
            .map(|block| match block {
                AnthropicContent::Text { text, .. } => ContentBlock::Text { text },
                AnthropicContent::ToolUse { id, name, input, .. } => {
                    ContentBlock::ToolUse { id, name, input }
                }
                AnthropicContent::ToolResult { .. } => {
                    // Shouldn't appear in responses, but handle gracefully
                    ContentBlock::Text {
                        text: "[tool_result in response]".to_string(),
                    }
                }
            })
            .collect();

        let stop_reason = match api_response.stop_reason.as_deref() {
            Some("end_turn") => StopReason::EndTurn,
            Some("tool_use") => StopReason::ToolUse,
            Some("max_tokens") => StopReason::MaxTokens,
            Some("stop_sequence") => StopReason::StopSequence,
            _ => StopReason::EndTurn,
        };

        let usage = api_response.usage.map(|u| Usage {
            input_tokens: u.input_tokens,
            output_tokens: u.output_tokens,
        });

        Ok(CompletionResponse {
            content,
            stop_reason,
            usage,
        })
    }

    fn name(&self) -> &str {
        "anthropic"
    }

    fn model_id(&self) -> &str {
        &self.model
    }

    fn supports_tools(&self) -> bool {
        true
    }
}

// =============================================================================
// Anthropic API wire types (private)
// =============================================================================

#[derive(Serialize)]
struct AnthropicRequest {
    model: String,
    max_tokens: u32,
    #[serde(skip_serializing_if = "Option::is_none")]
    system: Option<String>,
    messages: Vec<AnthropicMessage>,
    #[serde(skip_serializing_if = "Option::is_none")]
    tools: Option<Vec<AnthropicTool>>,
}

#[derive(Serialize)]
struct AnthropicMessage {
    role: String,
    content: Vec<AnthropicContent>,
}

#[derive(Serialize, Deserialize)]
#[serde(tag = "type")]
enum AnthropicContent {
    #[serde(rename = "text")]
    Text {
        text: String,
    },
    #[serde(rename = "tool_use")]
    ToolUse {
        id: String,
        name: String,
        input: serde_json::Value,
    },
    #[serde(rename = "tool_result")]
    ToolResult {
        tool_use_id: String,
        content: String,
        #[serde(default)]
        is_error: bool,
    },
}

#[derive(Serialize)]
struct AnthropicTool {
    name: String,
    description: String,
    input_schema: serde_json::Value,
}

#[derive(Deserialize)]
struct AnthropicResponse {
    content: Vec<AnthropicContent>,
    stop_reason: Option<String>,
    usage: Option<AnthropicUsage>,
}

#[derive(Deserialize)]
struct AnthropicUsage {
    input_tokens: u32,
    output_tokens: u32,
}