package main

import (
	"encoding/json"
	log "github.com/sirupsen/logrus"
	"net/http"
)

const API_PREFIX = "https://swapi.dev/api"

// Source: https://swapi.dev/documentation#people
type Person struct {
	Name string
	// ... other fields unused by this application
}

// Source: https://swapi.dev/documentation#starships
type Starship struct {
	Name   string
	Pilots []string // URLs to retrieve [People]
	// ... other fields unused by this application
}

// Structs which may be retrieved in a paginated fasion from swapi.dev
type Pageable interface {
	Starship | Person
}

type Gettable interface {
	Starship | Person
}

// Represents a single page of [Pageable] structs
type PageOf[T Pageable] struct {
	Count    uint
	Next     *string
	Previous *string
	Results  []T
}

// Used for retrieving data from swapi.dev
//
//	resp, err := Get("/starships")
//
// If [path] does not start with "/", it assumes you have provided a full URL to
// make following [PageOf]'s [Next] and [Previous] simpler.
//
//	resp, err := Get("https://git.lyte.dev/swagger.v1.json")
func Get[T interface{}](path string, data *T) error {
	var url string
	if path[0] == '/' {
		url = API_PREFIX + path
	} else {
		url = path
	}
	resp, err := http.Get(url)
	if err != nil {
		log.Errorf("Error GET'ing %s: %+v", url, err)
	}
	defer resp.Body.Close()
	err = json.NewDecoder(resp.Body).Decode(data)
	if err != nil {
		log.Errorf("Failed to decode response JSON: %+v", err)
	}
	log.Debugf("GET %s: %+v", url, resp)
	return err
}

func AllStarships() (*[]Starship, error) {
	results := make([]Starship, 0)
	var page PageOf[Starship]
	var resp *http.Response

	err := Get("/starships", &page)
	if err != nil {
		return &[]Starship{}, err
	}
	err = json.NewDecoder(resp.Body).Decode(&page)
	log.Debugf("Page: %+v", page)
	if err != nil {
		log.Errorf("Error decoding response body: %+v", err)
	}
	results = append(results, page.Results...)

	// TODO: loop
	for page.Next != nil {
		err := Get(*page.Next, &page)
		log.Debugf("Page: %+v", page)
		if err != nil {
			return &[]Starship{}, err
		}
		json.NewDecoder(resp.Body).Decode(&page)
		results = append(results, page.Results...)
	}
	return &results, nil
}