package main

import (
	"maps"
	"os"
	"reflect"
	"testing"
)

func TestCSVStorer_LoadSkipSet(t *testing.T) {
	tests := []struct {
		name string
		csv  string
		want map[int]struct{}
	}{
		{name: "empty", csv: "tmdb_id,rating,seen\n", want: map[int]struct{}{}},
		{name: "single", csv: "tmdb_id,rating,seen\n123,8,true\n", want: map[int]struct{}{123: {}}},
		{name: "multiple", csv: "tmdb_id,rating,seen\n1,,\n2,5,true\n", want: map[int]struct{}{1: {}, 2: {}}},
		{name: "skips header", csv: "tmdb_id,rating,seen\n1,,\n", want: map[int]struct{}{1: {}}},
		{name: "missing file", csv: "", want: map[int]struct{}{}},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			var path string
			if tt.csv == "" {
				path = "/nonexistent"
			} else {
				path = writeTempFile(t, tt.csv)
			}
			store := newCSVStorer()
			got, err := store.LoadSkipSet(path)
			if err != nil {
				t.Fatal(err)
			}
			if !maps.Equal(got, tt.want) {
				t.Errorf("got %v, want %v", got, tt.want)
			}
		})
	}
}

func TestCSVStorer_ReadWriteRoundtrip(t *testing.T) {
	tests := []struct {
		name    string
		entries []Entry
	}{
		{name: "empty", entries: nil},
		{name: "seen with rating", entries: []Entry{{ID: 1, Rating: 8, Seen: true}}},
		{name: "unseen", entries: []Entry{{ID: 1}}},
		{name: "seen no rating", entries: []Entry{{ID: 1, Seen: true}}},
		{name: "multiple", entries: []Entry{
			{ID: 1, Rating: 7, Seen: true},
			{ID: 2, Seen: false},
			{ID: 3, Rating: 9, Seen: true},
		}},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			f := tempFilePath(t)
			store := newCSVStorer()

			if err := store.WriteEntries(f, tt.entries); err != nil {
				t.Fatal(err)
			}
			got, err := store.ReadEntries(f)
			if err != nil {
				t.Fatal(err)
			}
			if tt.entries == nil && got != nil {
				t.Fatalf("want nil, got %v", got)
			}
			if tt.entries == nil {
				return
			}
			if !reflect.DeepEqual(tt.entries, got) {
				t.Errorf("mismatch:\n  want %+v\n  got  %+v", tt.entries, got)
			}
		})
	}
}

func writeTempFile(t *testing.T, content string) string {
	t.Helper()
	f, err := os.CreateTemp("", "popback-test-*.csv")
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { os.Remove(f.Name()) })
	if _, err := f.WriteString(content); err != nil {
		f.Close()
		t.Fatal(err)
	}
	f.Close()
	return f.Name()
}

func tempFilePath(t *testing.T) string {
	t.Helper()
	f, err := os.CreateTemp("", "popback-test-*.csv")
	if err != nil {
		t.Fatal(err)
	}
	f.Close()
	t.Cleanup(func() { os.Remove(f.Name()) })
	return f.Name()
}