package pow

import (
	"errors"
	"strings"
	"testing"
)

func TestKnownChallenge(t *testing.T) {
	challenge := Challenge{
		Algorithm:  "DeepSeekHashV1",
		Challenge:  "2f90572ad390d758b5e55b3bb74f14722166388023b3b28876d056a358591197",
		Salt:       "2eeb8f3a703002bfca70",
		Difficulty: 144000,
		ExpireAt:   1785483643587,
	}

	answer, err := challenge.Solve()
	if err != nil {
		t.Fatalf("Solve(): %v", err)
	}

	t.Logf("answer=%d", answer)

	/*
	 * Для этого challenge ожидается 61830.
	 */
	const expected uint64 = 61830

	if answer != expected {
		t.Fatalf(
			"unexpected answer: got %d, want %d",
			answer,
			expected,
		)
	}
}

func TestInvalidChallenge(t *testing.T) {
	validDigest := "2f90572ad390d758b5e55b3bb74f14722166388023b3b28876d056a358591197"
	tests := []struct {
		name       string
		base       string
		challenge  string
		difficulty uint64
	}{
		{name: "empty base", challenge: validDigest, difficulty: 1},
		{name: "short digest", base: "salt_123_", challenge: "not-hex", difficulty: 1},
		{name: "non-hex digest", base: "salt_123_", challenge: strings.Repeat("z", 64), difficulty: 1},
		{name: "zero difficulty", base: "salt_123_", challenge: validDigest},
		{name: "base exceeds one block", base: strings.Repeat("x", 116), challenge: validDigest, difficulty: 1},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			_, err := Solve(tt.base, tt.challenge, tt.difficulty)
			if !errors.Is(err, ErrInvalidArgument) {
				t.Fatalf("Solve() error = %v, want ErrInvalidArgument", err)
			}
		})
	}
}

func TestChallengeValidation(t *testing.T) {
	validDigest := "2f90572ad390d758b5e55b3bb74f14722166388023b3b28876d056a358591197"
	tests := []struct {
		name      string
		challenge Challenge
		wantMatch bool
	}{
		{name: "unsupported algorithm", challenge: Challenge{Algorithm: "other", Challenge: validDigest, Salt: "salt", Difficulty: 1}},
		{name: "invalid digest", challenge: Challenge{Challenge: "short", Salt: "salt", Difficulty: 1}, wantMatch: true},
		{name: "empty salt", challenge: Challenge{Challenge: validDigest, Difficulty: 1}, wantMatch: true},
		{name: "zero difficulty", challenge: Challenge{Challenge: validDigest, Salt: "salt"}, wantMatch: true},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			_, err := tt.challenge.Solve()
			if err == nil {
				t.Fatal("Challenge.Solve() error = nil")
			}
			if tt.wantMatch && !errors.Is(err, ErrInvalidArgument) {
				t.Fatalf("Challenge.Solve() error = %v, want ErrInvalidArgument", err)
			}
		})
	}
}