//! HTTP handlers for history and conversation APIs.

use axum::{
    extract::{Path, Query, State},
    http::StatusCode,
    response::IntoResponse,
    Json,
};
use uuid::Uuid;

use crate::{
    db::{
        models::{flexible_datetime, ConversationMessage, HistoryQueryFilters, TaskConversationResponse},
        repository,
    },
    server::{auth::Authenticated, messages::ApiError, state::SharedState},
};

/// Query parameters for task conversation
#[derive(Debug, serde::Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct TaskConversationParams {
    pub include_tool_calls: Option<bool>,
    pub include_tool_results: Option<bool>,
    pub limit: Option<i32>,
}

/// Query parameters for timeline
#[derive(Debug, serde::Deserialize)]
#[serde(rename_all = "camelCase")]
pub struct TimelineQueryFilters {
    pub task_id: Option<Uuid>,
    pub include_subtasks: Option<bool>,
    #[serde(default, deserialize_with = "flexible_datetime::deserialize")]
    pub from: Option<chrono::DateTime<chrono::Utc>>,
    #[serde(default, deserialize_with = "flexible_datetime::deserialize")]
    pub to: Option<chrono::DateTime<chrono::Utc>>,
    pub limit: Option<i32>,
}

#[utoipa::path(
    get,
    path = "/api/v1/mesh/tasks/{id}/conversation",
    params(
        ("id" = Uuid, Path, description = "Task ID"),
        ("include_tool_calls" = Option<bool>, Query, description = "Include tool call messages"),
        ("include_tool_results" = Option<bool>, Query, description = "Include tool result messages"),
        ("limit" = Option<i32>, Query, description = "Limit messages"),
    ),
    responses(
        (status = 200, description = "Task conversation", body = TaskConversationResponse),
        (status = 401, description = "Unauthorized", body = ApiError),
        (status = 403, description = "Forbidden", body = ApiError),
        (status = 404, description = "Task not found", body = ApiError),
        (status = 503, description = "Database not configured", body = ApiError),
        (status = 500, description = "Internal server error", body = ApiError),
    ),
    security(
        ("bearer_auth" = []),
        ("api_key" = [])
    ),
    tag = "History"
)]
pub async fn get_task_conversation(
    State(state): State<SharedState>,
    Path(task_id): Path<Uuid>,
    Query(params): Query<TaskConversationParams>,
    Authenticated(auth): Authenticated,
) -> impl IntoResponse {
    let Some(ref pool) = state.db_pool else {
        return (
            StatusCode::SERVICE_UNAVAILABLE,
            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
        )
            .into_response();
    };

    // Get task and verify ownership
    let task = match repository::get_task_for_owner(pool, task_id, auth.owner_id).await {
        Ok(Some(t)) => t,
        Ok(None) => {
            return (
                StatusCode::NOT_FOUND,
                Json(ApiError::new("NOT_FOUND", "Task not found")),
            )
                .into_response();
        }
        Err(e) => {
            tracing::error!("Failed to get task {}: {}", task_id, e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(ApiError::new("DB_ERROR", e.to_string())),
            )
                .into_response();
        }
    };

    // Get conversation messages
    let messages = match repository::get_task_conversation(
        pool,
        task_id,
        params.include_tool_calls.unwrap_or(true),
        params.include_tool_results.unwrap_or(true),
        params.limit,
    )
    .await
    {
        Ok(m) => m,
        Err(e) => {
            tracing::error!("Failed to get task conversation: {}", e);
            return (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(ApiError::new("DB_ERROR", e.to_string())),
            )
                .into_response();
        }
    };

    // Calculate totals
    let total_cost: f64 = messages.iter().filter_map(|m| m.cost_usd).sum();

    Json(TaskConversationResponse {
        task_id,
        task_name: task.name,
        status: task.status,
        messages,
        total_tokens: None,
        total_cost: if total_cost > 0.0 {
            Some(total_cost)
        } else {
            None
        },
    })
    .into_response()
}

/// GET /api/v1/timeline
/// Returns unified task-history timeline for the authenticated user.
#[utoipa::path(
    get,
    path = "/api/v1/timeline",
    responses(
        (status = 200, description = "Timeline events"),
        (status = 401, description = "Unauthorized", body = ApiError),
        (status = 503, description = "Database not configured", body = ApiError),
    ),
    security(("bearer_auth" = []), ("api_key" = [])),
    tag = "History"
)]
pub async fn get_timeline(
    State(state): State<SharedState>,
    Query(filters): Query<TimelineQueryFilters>,
    Authenticated(auth): Authenticated,
) -> impl IntoResponse {
    let Some(ref pool) = state.db_pool else {
        return (
            StatusCode::SERVICE_UNAVAILABLE,
            Json(ApiError::new("DB_UNAVAILABLE", "Database not configured")),
        )
            .into_response();
    };

    let history_filters = HistoryQueryFilters {
        event_types: None,
        from: filters.from,
        to: filters.to,
        limit: filters.limit,
        cursor: None,
    };

    let result = if let Some(task_id) = filters.task_id {
        repository::get_task_history(pool, task_id, auth.owner_id, &history_filters).await
    } else {
        repository::get_timeline(pool, auth.owner_id, &history_filters).await
    };

    match result {
        Ok((events, total_count)) => Json(serde_json::json!({
            "entries": events,
            "totalCount": total_count,
        }))
        .into_response(),
        Err(e) => {
            tracing::error!("Failed to get timeline: {}", e);
            (
                StatusCode::INTERNAL_SERVER_ERROR,
                Json(ApiError::new("DB_ERROR", e.to_string())),
            )
                .into_response()
        }
    }
}