package providers

import (
	"context"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

// TestOpenLibrarySearchDBFree is the point of the split: a provider is an HTTP
// client, so it is exercisable end to end against a stub server with no
// database anywhere in sight.
func TestOpenLibrarySearchDBFree(t *testing.T) {
	var gotTitle, gotAuthor, gotLimit, gotUA string

	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/search.json" {
			t.Errorf("path = %q, want /search.json", r.URL.Path)
		}
		q := r.URL.Query()
		gotTitle, gotAuthor, gotLimit = q.Get("title"), q.Get("author"), q.Get("limit")
		gotUA = r.Header.Get("User-Agent")
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"docs":[
			{"key":"/works/OL45804W","title":"The Hobbit","author_name":["J.R.R. Tolkien"],
			 "first_publish_year":1937,"publisher":["Allen & Unwin"],"language":["eng"],
			 "cover_i":8225261,"isbn":["9780261102217"]},
			{"key":"/works/OL1W","title":"","author_name":["Nobody"]}
		]}`))
	}))
	defer srv.Close()

	p := NewOpenLibrary()
	p.BaseURL = srv.URL

	cands, err := p.Search(context.Background(), Query{Title: "The Hobbit", Author: "Tolkien"})
	if err != nil {
		t.Fatalf("Search: %v", err)
	}
	// The untitled doc is dropped rather than surfaced as an empty candidate.
	if len(cands) != 1 {
		t.Fatalf("got %d candidates, want 1", len(cands))
	}

	c := cands[0]
	if c.Provider != "openlibrary" || c.ExternalID != "/works/OL45804W" {
		t.Errorf("provider id = %s/%s", c.Provider, c.ExternalID)
	}
	if c.Title != "The Hobbit" || c.Year != 1937 {
		t.Errorf("title/year = %q/%d", c.Title, c.Year)
	}
	if len(c.Authors) != 1 || c.Authors[0] != "J.R.R. Tolkien" {
		t.Errorf("Authors = %v", c.Authors)
	}
	if c.Publisher != "Allen & Unwin" || c.Language != "eng" {
		t.Errorf("publisher/language = %q/%q", c.Publisher, c.Language)
	}
	if c.ISBN != "9780261102217" {
		t.Errorf("ISBN = %q", c.ISBN)
	}
	if !strings.Contains(c.CoverURL, "covers.openlibrary.org/b/id/8225261") {
		t.Errorf("CoverURL = %q", c.CoverURL)
	}

	if gotTitle != "The Hobbit" || gotAuthor != "Tolkien" {
		t.Errorf("query title/author = %q/%q", gotTitle, gotAuthor)
	}
	if gotLimit != "5" {
		t.Errorf("limit = %q, want 5", gotLimit)
	}
	if gotUA == "" {
		t.Error("no User-Agent sent; Open Library asks callers to identify themselves")
	}
}

func TestOpenLibrarySkipsRequestWithoutATerm(t *testing.T) {
	p := NewOpenLibrary()
	cands, err := p.Search(context.Background(), Query{})
	if err != nil {
		t.Fatalf("Search: %v", err)
	}
	if len(cands) != 0 {
		t.Errorf("got %d candidates for an empty query, want 0", len(cands))
	}
}

func TestOpenLibraryReportsHTTPFailure(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusTooManyRequests)
	}))
	defer srv.Close()

	p := NewOpenLibrary()
	p.BaseURL = srv.URL

	if _, err := p.Search(context.Background(), Query{Title: "The Hobbit"}); err == nil {
		t.Fatal("expected an error for a 429 response")
	}
}