// Copyright (C) 2024 Riften Labs AS
//
// This software is licensed under the GNU Affero General Public License (AGPL), version 3.0 or later.
// A copy of the license can be found in the LICENSE file or at https://www.gnu.org/licenses/agpl-3.0.html

use rocket::{http::Status, response::status::Custom, serde::json::Json};
use serde_json::{json, Value};
use std::fmt;

use super::response::CachedJson;

/// Standard API result type with JSON-formatted errors (without caching headers)
#[allow(dead_code)]
pub type ApiResult<T> = Result<Json<T>, Custom<Json<Value>>>;

/// API result type with Cache-Control headers for cacheable responses
pub type CachedApiResult<T> = Result<CachedJson<T>, Custom<Json<Value>>>;

/// API error codes for consistent error responses
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum ApiErrorCode {
    // 400 Bad Request codes
    InvalidTimestamp,
    InvalidTokenId,
    InvalidPoolId,
    InvalidTxid,
    InvalidParameters,
    InvalidTimeRange,
    InvalidStepsize,
    MissingParameters,
    MissingCategory,
    TooManyIntervals,
    FutureTimestamp,

    // 404 Not Found codes
    PriceNotFound,
    PoolNotFound,

    // 500 Internal Server Error codes
    InternalError,

    // 503 Service Unavailable codes
    CacheWarming,
}

impl fmt::Display for ApiErrorCode {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let s = match self {
            // 400 codes
            Self::InvalidTimestamp => "INVALID_TIMESTAMP",
            Self::InvalidTokenId => "INVALID_TOKEN_ID",
            Self::InvalidPoolId => "INVALID_POOL_ID",
            Self::InvalidTxid => "INVALID_TXID",
            Self::InvalidParameters => "INVALID_PARAMETERS",
            Self::InvalidTimeRange => "INVALID_TIME_RANGE",
            Self::InvalidStepsize => "INVALID_STEPSIZE",
            Self::MissingParameters => "MISSING_PARAMETERS",
            Self::MissingCategory => "MISSING_CATEGORY",
            Self::TooManyIntervals => "TOO_MANY_INTERVALS",
            Self::FutureTimestamp => "FUTURE_TIMESTAMP",
            // 404 codes
            Self::PriceNotFound => "PRICE_NOT_FOUND",
            Self::PoolNotFound => "POOL_NOT_FOUND",
            // 500 codes
            Self::InternalError => "INTERNAL_ERROR",
            // 503 codes
            Self::CacheWarming => "CACHE_WARMING",
        };
        write!(f, "{s}")
    }
}

/// Create a 400 Bad Request error with JSON body
pub fn bad_request(code: ApiErrorCode, message: &str) -> Custom<Json<Value>> {
    Custom(
        Status::BadRequest,
        Json(json!({
            "error": { "code": code.to_string(), "message": message }
        })),
    )
}

/// Create a 404 Not Found error with JSON body
pub fn not_found(code: ApiErrorCode, message: &str) -> Custom<Json<Value>> {
    Custom(
        Status::NotFound,
        Json(json!({
            "error": { "code": code.to_string(), "message": message }
        })),
    )
}

/// Create a 500 Internal Server Error with JSON body
pub fn internal_error(message: &str) -> Custom<Json<Value>> {
    Custom(
        Status::InternalServerError,
        Json(json!({
            "error": { "code": ApiErrorCode::InternalError.to_string(), "message": message }
        })),
    )
}

/// Create a 500 Internal Server Error for database errors with JSON body
pub fn db_error<E: std::fmt::Display>(e: E) -> Custom<Json<Value>> {
    internal_error(&format!("Database error: {e}"))
}

/// Create a 503 Service Unavailable error with JSON body
pub fn service_unavailable(code: ApiErrorCode, message: &str) -> Custom<Json<Value>> {
    Custom(
        Status::ServiceUnavailable,
        Json(json!({
            "error": { "code": code.to_string(), "message": message }
        })),
    )
}

// Legacy helper for backward compatibility during migration
pub fn to_internal_error<E: std::fmt::Display>(e: E) -> Custom<String> {
    Custom(Status::InternalServerError, format!("Error: {e}"))
}