// The Swift Programming Language
// https://docs.swift.org/swift-book

import Foundation

public final class USDA_FDC_Client {
    var version = 1
    var baseURL: URL {
        URL(string: "https://api.nal.usda.gov/fdc/v\(version)")!
    }

    public init() {}

    public var apiKey: String = ""

    public func getFood(_ foodCriteria: FoodCriteria) async throws -> AbridgedFoodItem {
        var endpoint = baseURL.appendingPathComponent("/food/\(foodCriteria.fdcId)")
        endpoint.append(queryItems: [.init(name: "api_key", value: apiKey)])
        // if criteria != nil {
        //     for (key, value) in Mirror(reflecting: criteria!).children {
        //         if value as Any? != nil {
        //             if let l = value as? [String] {
        //                 endpoint.append(queryItems: [.init(name: key!, value: String(describing: l.joined(separator: ",")))])
        //             }
        //             endpoint.append(queryItems: [.init(name: key!, value: String(describing: value))])
        //         }
        //     }
        // }
        print(endpoint)
        var request = URLRequest(url: endpoint)
        request.setValue("application/json", forHTTPHeaderField: "accept")
        let (data, response) = try await URLSession.shared.data(for: request)
        guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
            throw FDCError.invalidResponse
        }
        do {
            return try JSONDecoder().decode(AbridgedFoodItem.self, from: data)
        } catch {
            throw error
        }
    }

    // TODO: 
    public func getFoods(_ foodsCriteria: FoodsCriteria) async throws -> [AbridgedFoodItem] {
        var endpoint = baseURL.appendingPathComponent("/food")
        endpoint.append(queryItems: [.init(name: "api_key", value: apiKey)])
        // if criteria != nil {
        //     for (key, value) in Mirror(reflecting: criteria!).children {
        //         if value as Any? != nil {
        //             if let l = value as? [String] {
        //                 endpoint.append(queryItems: [.init(name: key!, value: String(describing: l.joined(separator: ",")))])
        //             }
        //             endpoint.append(queryItems: [.init(name: key!, value: String(describing: value))])
        //         }
        //     }
        // }
        print(endpoint)
        var request = URLRequest(url: endpoint)
        request.setValue("application/json", forHTTPHeaderField: "accept")
        let (data, response) = try await URLSession.shared.data(for: request)
        guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
            throw FDCError.invalidResponse
        }
        do {
            return try JSONDecoder().decode([AbridgedFoodItem].self, from: data)
        } catch {
            throw error
        }
    }

    public func getFoodsSearch(_ search: FoodSearchCriteria) async throws -> SearchResult {
        var endpoint = baseURL.appendingPathComponent("/foods/search")
        endpoint.append(queryItems: [.init(name: "api_key", value: apiKey)])
        endpoint.append(queryItems: [.init(name: "query", value: search.query)])
        // if criteria != nil {
        //     for (key, value) in Mirror(reflecting: criteria!).children {
        //         if value as Any? != nil {
        //             if let l = value as? [String] {
        //                 endpoint.append(queryItems: [.init(name: key!, value: String(describing: l.joined(separator: ",")))])
        //             }
        //             endpoint.append(queryItems: [.init(name: key!, value: String(describing: value))])
        //         }
        //     }
        // }
        print(endpoint)
        var request = URLRequest(url: endpoint)
        request.setValue("application/json", forHTTPHeaderField: "accept")
        let (data, response) = try await URLSession.shared.data(for: request)
        guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
            throw FDCError.invalidResponse
        }
        do {
            return try JSONDecoder().decode(SearchResult.self, from: data)
        } catch {
            throw error
        }
    }

    public func getFoodList(_: FoodListCriteria? = nil) async throws -> [AbridgedFoodItem] {
        var endpoint = baseURL.appendingPathComponent("/foods/list")
        endpoint.append(queryItems: [.init(name: "api_key", value: apiKey)])
        // if criteria != nil {
        //     for (key, value) in Mirror(reflecting: criteria!).children {
        //         if value as Any? != nil {
        //             if let l = value as? [String] {
        //                 endpoint.append(queryItems: [.init(name: key!, value: String(describing: l.joined(separator: ",")))])
        //             }
        //             endpoint.append(queryItems: [.init(name: key!, value: String(describing: value))])
        //         }
        //     }
        // }
        print(endpoint)
        var request = URLRequest(url: endpoint)
        request.setValue("application/json", forHTTPHeaderField: "accept")
        let (data, response) = try await URLSession.shared.data(for: request)
        guard let response = response as? HTTPURLResponse, response.statusCode == 200 else {
            throw FDCError.invalidResponse
        }
        do {
            return try JSONDecoder().decode([AbridgedFoodItem].self, from: data)
        } catch {
            throw error
        }
    }
}

public enum FDCError: Error {
    case invalidResponse
}