package sudoku

import (
	"crypto/sha1"
	"errors"
	"fmt"
	"testing"

	"git.kleiax.de/homepage/logic"
	"git.kleiax.de/homepage/logic/strategies"
	"git.kleiax.de/homepage/parser"
)

const solvedSudoku = "123456789456789123789123456234567891567891234891234567345678912678912345912345678"

func puzzleBankRecord(digits string, rating float64) string {
	hash := fmt.Sprintf("%x", sha1.Sum([]byte(digits)))[:12]
	return fmt.Sprintf("%s %s   %.1f", hash, digits, rating)
}

func TestNewSelectsExplicitPuzzleIndex(t *testing.T) {
	data := puzzleBankRecord("0"+solvedSudoku[1:], 1.0) + "\n" + puzzleBankRecord(solvedSudoku, 2.0)
	game, err := New(&parser.PuzzleBank{}, logic.Solver{}, []byte(data), 1)
	if err != nil {
		t.Fatalf("New() error = %v", err)
	}
	if game.GetField().GetRating() != 2 || !game.GetField().IsSolved() {
		t.Fatal("New() did not select puzzle index 1")
	}
}

func TestNewRejectsInvalidIndexAndInput(t *testing.T) {
	valid := puzzleBankRecord(solvedSudoku, 1.0)
	if _, err := New(&parser.PuzzleBank{}, logic.Solver{}, []byte(valid), 1); !errors.Is(err, parser.ErrFieldIndex) {
		t.Fatalf("index error = %v, want ErrFieldIndex", err)
	}
	if _, err := New(&parser.PuzzleString{}, logic.Solver{}, []byte("invalid"), 0); err == nil {
		t.Fatal("invalid input error = nil")
	}
}

func TestSolveCompletesSimplePuzzle(t *testing.T) {
	solver := logic.Solver{}
	solver.Add(&strategies.LastDigit{})
	game, err := New(&parser.PuzzleString{}, solver, []byte("0"+solvedSudoku[1:]), 0)
	if err != nil {
		t.Fatal(err)
	}
	if err := game.Solve(); err != nil {
		t.Fatalf("Solve() error = %v", err)
	}
	if !game.GetField().IsSolved() {
		t.Fatal("field is not solved")
	}
}

func TestSolveReportsNoProgress(t *testing.T) {
	game, err := New(&parser.PuzzleString{}, logic.Solver{}, []byte("0"+solvedSudoku[1:]), 0)
	if err != nil {
		t.Fatal(err)
	}
	if err := game.Solve(); !errors.Is(err, logic.ErrNoProgress) {
		t.Fatalf("Solve() error = %v, want ErrNoProgress", err)
	}
}