package logic_test

import (
	"errors"
	"testing"

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

const solvedPuzzle = "123456789456789123789123456234567891567891234891234567345678912678912345912345678"

func parsedField(t *testing.T, puzzle string) *field.Field {
	t.Helper()
	input := &parser.PuzzleString{}
	if err := input.Parse([]byte(puzzle)); err != nil {
		t.Fatal(err)
	}
	result, err := input.GetField(0)
	if err != nil {
		t.Fatal(err)
	}
	return result
}

func TestSolverRunSolvesAndDetectsNoProgress(t *testing.T) {
	t.Run("solved", func(t *testing.T) {
		f := parsedField(t, "0"+solvedPuzzle[1:])
		solver := &logic.Solver{}
		solver.Add(&strategies.LastDigit{})
		if err := solver.InitStrategies(f); err != nil {
			t.Fatal(err)
		}
		solved, err := solver.Run(0)
		if err != nil || !solved || !f.IsSolved() {
			t.Fatalf("Run() = (%v, %v), field solved = %v", solved, err, f.IsSolved())
		}
	})

	t.Run("no progress", func(t *testing.T) {
		f := parsedField(t, "0"+solvedPuzzle[1:])
		solver := &logic.Solver{}
		if err := solver.InitStrategies(f); err != nil {
			t.Fatal(err)
		}
		solved, err := solver.Run(0)
		if err != nil || solved {
			t.Fatalf("Run() = (%v, %v), want (false, nil)", solved, err)
		}
	})
}

func TestSolverRejectsInvalidStateAndStrategyIndex(t *testing.T) {
	solver := &logic.Solver{}
	if _, err := solver.Run(0); !errors.Is(err, field.ErrInvalidField) {
		t.Fatalf("Run() before initialization error = %v", err)
	}
	if err := solver.InitStrategies(nil); !errors.Is(err, field.ErrInvalidField) {
		t.Fatalf("InitStrategies(nil) error = %v", err)
	}

	f := parsedField(t, "0"+solvedPuzzle[1:])
	if err := solver.InitStrategies(f); err != nil {
		t.Fatal(err)
	}
	if _, err := solver.Run(1); err == nil {
		t.Fatal("Run() with invalid strategy index error = nil")
	}
}