package config

import (
	"strings"
	"testing"
)

// TestCacheMaxBytesExplicitValueUsedWithoutFloor verifies that an
// explicitly configured cache_max_bytes value is used exactly as
// given: the 500 MiB floor applies only to the computed default, never
// to explicit values.
func TestCacheMaxBytesExplicitValueUsedWithoutFloor(t *testing.T) {
	t.Parallel()

	yamlContent := "signing_key: " + validTestSigningKey + "\ncache_max_bytes: 1024\n"

	c, err := configFromYAML(t, yamlContent)
	if err != nil {
		t.Fatalf("explicit cache_max_bytes must be accepted, got error: %v", err)
	}

	if c.CacheMaxBytes != 1024 {
		t.Errorf("CacheMaxBytes = %d, want 1024 (no floor for explicit values)",
			c.CacheMaxBytes)
	}
}

// TestCacheMaxBytesZeroIsValidAndDisablesCache verifies that an
// explicit zero is a valid value (it disables the disk cache), not an
// error.
func TestCacheMaxBytesZeroIsValidAndDisablesCache(t *testing.T) {
	t.Parallel()

	yamlContent := "signing_key: " + validTestSigningKey + "\ncache_max_bytes: 0\n"

	c, err := configFromYAML(t, yamlContent)
	if err != nil {
		t.Fatalf("cache_max_bytes: 0 must be accepted, got error: %v", err)
	}

	if c.CacheMaxBytes != 0 {
		t.Errorf("CacheMaxBytes = %d, want 0", c.CacheMaxBytes)
	}
}

// TestCacheMaxBytesLargeExplicitValueParses verifies that values above
// 32-bit range parse correctly (the field is an int64 byte count).
func TestCacheMaxBytesLargeExplicitValueParses(t *testing.T) {
	t.Parallel()

	yamlContent := "signing_key: " + validTestSigningKey +
		"\ncache_max_bytes: 10737418240\n"

	c, err := configFromYAML(t, yamlContent)
	if err != nil {
		t.Fatalf("large cache_max_bytes must be accepted, got error: %v", err)
	}

	if c.CacheMaxBytes != 10737418240 {
		t.Errorf("CacheMaxBytes = %d, want 10737418240", c.CacheMaxBytes)
	}
}

// TestCacheMaxBytesInvalidValuesAbortStartup verifies that a SET but
// invalid cache_max_bytes value aborts startup naming the key and the
// offending value, per the no-silent-fallback rule: defaults apply
// only to omitted keys.
func TestCacheMaxBytesInvalidValuesAbortStartup(t *testing.T) {
	t.Parallel()

	signingKeyLine := "signing_key: " + validTestSigningKey + "\n"

	cases := []struct {
		name string
		yaml string
		// wantErrSubstrings must all appear in the error message.
		wantErrSubstrings []string
	}{
		{
			name:              "negative",
			yaml:              signingKeyLine + "cache_max_bytes: -1024\n",
			wantErrSubstrings: []string{keyCacheMaxBytes, "-1024"},
		},
		{
			name:              "float",
			yaml:              signingKeyLine + "cache_max_bytes: 3.5\n",
			wantErrSubstrings: []string{keyCacheMaxBytes, "3.5"},
		},
		{
			name:              "non-numeric string",
			yaml:              signingKeyLine + "cache_max_bytes: banana\n",
			wantErrSubstrings: []string{keyCacheMaxBytes, "banana"},
		},
		{
			name:              "explicit null",
			yaml:              signingKeyLine + "cache_max_bytes: null\n",
			wantErrSubstrings: []string{keyCacheMaxBytes, "null"},
		},
		{
			name:              "bare key no value",
			yaml:              signingKeyLine + "cache_max_bytes:\n",
			wantErrSubstrings: []string{keyCacheMaxBytes, "null"},
		},
		{
			name:              "boolean",
			yaml:              signingKeyLine + "cache_max_bytes: true\n",
			wantErrSubstrings: []string{keyCacheMaxBytes, "true"},
		},
		{
			name:              "list",
			yaml:              signingKeyLine + "cache_max_bytes:\n  - 1\n",
			wantErrSubstrings: []string{keyCacheMaxBytes},
		},
	}

	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			t.Parallel()

			c, err := configFromYAML(t, tc.yaml)
			if err == nil {
				t.Fatalf(
					"config with %s cache_max_bytes must abort startup, got config: %+v",
					tc.name, c)
			}

			t.Logf("got expected error: %v", err)

			for _, want := range tc.wantErrSubstrings {
				if !strings.Contains(err.Error(), want) {
					t.Errorf("error %q does not mention %q", err.Error(), want)
				}
			}
		})
	}
}

// TestCacheMaxBytesExplicitIsRecorded verifies that an omitted
// cache_max_bytes is recorded as not explicit, so the cache works out
// the default when it opens, and that an explicit zero is recorded as
// explicit, so it disables the disk cache instead.
func TestCacheMaxBytesExplicitIsRecorded(t *testing.T) {
	t.Parallel()

	signingKeyLine := "signing_key: " + validTestSigningKey + "\n"

	omitted, err := configFromYAML(t, signingKeyLine)
	if err != nil {
		t.Fatalf("minimal config should be valid, got error: %v", err)
	}

	if omitted.CacheMaxBytesExplicit {
		t.Error("omitted cache_max_bytes recorded as explicit")
	}

	zero, err := configFromYAML(t, signingKeyLine+"cache_max_bytes: 0\n")
	if err != nil {
		t.Fatalf("cache_max_bytes: 0 must be accepted, got error: %v", err)
	}

	if !zero.CacheMaxBytesExplicit {
		t.Error("cache_max_bytes: 0 not recorded as explicit")
	}
}