use actix_web::{HttpResponse, web};
use serde::{Deserialize, Serialize};
use utoipa::{IntoParams, ToSchema};

use crate::api::response::{ApiErrorResponse, ApiResponse};
use crate::error::AppError;
use crate::models::wiki::WikiPageRevision;
use crate::service::AppService;
use crate::session::Session;

#[derive(Debug, Deserialize, IntoParams)]
pub struct PathParams {
    /// Workspace name (unique identifier)
    pub workspace_name: String,
    /// Repository name (unique within the workspace)
    pub repo_name: String,
    /// Wiki page slug (URL-friendly identifier)
    pub slug: String,
}

#[derive(Debug, Deserialize, IntoParams)]
pub struct QueryParams {
    /// Older version number to compare from
    pub old_version: i32,
    /// Newer version number to compare to
    pub new_version: i32,
}

/// Result of comparing two wiki page revisions
#[derive(Debug, Serialize, Deserialize, ToSchema)]
pub struct WikiCompareResult {
    /// The older revision being compared
    pub old: WikiPageRevision,
    /// The newer revision being compared
    pub new: WikiPageRevision,
}

/// Compare two wiki page revisions
///
/// Compares two versions of a wiki page and returns both revisions.
/// Requires read access to the repository.
///
/// Returns the old and new revisions for client-side diff computation.
/// The client can compute the diff between the two content snapshots.
#[utoipa::path(
    get,
    path = "/api/v1/workspaces/{workspace_name}/repos/{repo_name}/wiki/{slug}/compare",
    tag = "Wiki",
    operation_id = "wikiCompareRevisions",
    params(PathParams, QueryParams),
    responses(
        (status = 200, description = "Revisions compared successfully. Returns old and new revision objects.", body = ApiResponse<WikiCompareResult>),
        (status = 400, description = "Invalid version numbers", body = ApiErrorResponse),
        (status = 401, description = "Authentication required or session expired", body = ApiErrorResponse),
        (status = 403, description = "Insufficient permissions to access this repository", body = ApiErrorResponse),
        (status = 404, description = "Wiki page, revisions, repository, or workspace not found", body = ApiErrorResponse),
        (status = 500, description = "Internal server error", body = ApiErrorResponse),
    ),
    security(("session_cookie" = []))
)]
pub async fn compare_revisions(
    service: web::Data<AppService>,
    session: Session,
    path: web::Path<PathParams>,
    query: web::Query<QueryParams>,
) -> Result<HttpResponse, AppError> {
    let (old, new) = service
        .repo
        .wiki_compare_revisions(
            &session,
            &path.workspace_name,
            &path.repo_name,
            &path.slug,
            query.old_version,
            query.new_version,
        )
        .await?;
    Ok(HttpResponse::Ok().json(ApiResponse::new(WikiCompareResult { old, new })))
}