use actix_web::{web, HttpResponse, Result};
use session::Session;
use service::error::AppError;
use uuid::Uuid;

use crate::error::ApiError;
use crate::ApiResponse;

#[derive(Debug, serde::Serialize, utoipa::ToSchema)]
pub struct ForkResponse {
    pub id: Uuid,
    pub conversation_id: Option<Uuid>,
    pub source_message_id: Uuid,
    pub fork_message_id: Uuid,
    #[schema(value_type = chrono::DateTime<chrono::Utc>)]
    pub created_at: chrono::DateTime<chrono::Utc>,
}

#[utoipa::path(
    post,
    path = "/api/ai/conversations/{conversation_id}/messages/{message_id}/fork/{target_message_id}",
    operation_id = "ai_message_fork",
    params(
        ("conversation_id" = Uuid, Path, description = "Conversation ID"),
        ("message_id" = Uuid, Path, description = "Source message ID"),
        ("target_message_id" = Uuid, Path, description = "Target/fork message ID to create"),
    ),
    responses(
        (status = 200, description = "Fork created", body = ApiResponse<ForkResponse>),
    ),
    tag = "AI Chat"
)]
pub async fn message_fork(
    service: web::Data<service::AppService>,
    session: Session,
    path: web::Path<(Uuid, Uuid, Uuid)>,
) -> Result<HttpResponse, ApiError> {
    let user_id = session
        .user()
        .ok_or_else(|| ApiError::from(AppError::Unauthorized))?;
    let (conversation_id, source_message_id, target_message_id) = path.into_inner();

    let fork_record = service
        .fork_message(
            conversation_id,
            user_id,
            source_message_id,
            target_message_id,
        )
        .await?;

    let resp = ForkResponse {
        id: fork_record.id,
        conversation_id: fork_record.conversation_id,
        source_message_id: fork_record.source_message_id,
        fork_message_id: fork_record.fork_message_id,
        created_at: fork_record.created_at,
    };

    Ok(ApiResponse::ok(resp).to_response())
}

#[utoipa::path(
    get,
    path = "/api/ai/conversations/{conversation_id}/messages/{message_id}/forks",
    operation_id = "ai_message_forks",
    params(
        ("conversation_id" = Uuid, Path, description = "Conversation ID"),
        ("message_id" = Uuid, Path, description = "Source message ID"),
    ),
    responses(
        (status = 200, description = "List forks from message", body = ApiResponse<Vec<ForkResponse>>),
    ),
    tag = "AI Chat"
)]
pub async fn message_forks(
    service: web::Data<service::AppService>,
    session: Session,
    path: web::Path<(Uuid, Uuid)>,
) -> Result<HttpResponse, ApiError> {
    let user_id = session
        .user()
        .ok_or_else(|| ApiError::from(AppError::Unauthorized))?;
    let (conversation_id, source_message_id) = path.into_inner();

    let forks = service
        .list_forks(conversation_id, user_id, source_message_id)
        .await?;

    let resp: Vec<ForkResponse> = forks
        .into_iter()
        .map(|f| ForkResponse {
            id: f.id,
            conversation_id: f.conversation_id,
            source_message_id: f.source_message_id,
            fork_message_id: f.fork_message_id,
            created_at: f.created_at,
        })
        .collect();

    Ok(ApiResponse::ok(resp).to_response())
}