package chatloop

import (
	"context"
	"encoding/base64"
	"errors"
	"iter"
	"sync"
	"sync/atomic"
	"testing"
	"time"
	"unicode/utf8"

	"charm.land/fantasy"
	fantasyanthropic "charm.land/fantasy/providers/anthropic"
	"github.com/prometheus/client_golang/prometheus"
	promtestutil "github.com/prometheus/client_golang/prometheus/testutil"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"golang.org/x/xerrors"

	"cdr.dev/slog/v3"
	"github.com/coder/coder/v2/coderd/x/chatd/chaterror"
	"github.com/coder/coder/v2/coderd/x/chatd/chatsanitize"
	"github.com/coder/coder/v2/coderd/x/chatd/chattest"
	"github.com/coder/coder/v2/codersdk"
	"github.com/coder/coder/v2/testutil"
	"github.com/coder/quartz"
)

func validWebSearchProviderMetadataForTest() fantasy.ProviderMetadata {
	return fantasy.ProviderMetadata{
		fantasyanthropic.Name: &fantasyanthropic.WebSearchResultMetadata{
			Results: []fantasyanthropic.WebSearchResultItem{
				{
					URL:              "https://example.com",
					Title:            "Example",
					EncryptedContent: "encrypted",
				},
			},
		},
	}
}

func safeToolCallContent(block fantasy.Content) (fantasy.ToolCallContent, bool) {
	var zero fantasy.ToolCallContent
	switch value := block.(type) {
	case fantasy.ToolCallContent:
		return value, true
	case *fantasy.ToolCallContent:
		if value == nil {
			return zero, false
		}
		return *value, true
	default:
		return zero, false
	}
}

func safeToolResultContent(block fantasy.Content) (fantasy.ToolResultContent, bool) {
	var zero fantasy.ToolResultContent
	switch value := block.(type) {
	case fantasy.ToolResultContent:
		return value, true
	case *fantasy.ToolResultContent:
		if value == nil {
			return zero, false
		}
		return *value, true
	default:
		return zero, false
	}
}

func toolCallContentToPart(toolCall fantasy.ToolCallContent) fantasy.ToolCallPart {
	return fantasy.ToolCallPart{
		ToolCallID:       toolCall.ToolCallID,
		ToolName:         toolCall.ToolName,
		Input:            toolCall.Input,
		ProviderExecuted: toolCall.ProviderExecuted,
		ProviderOptions:  fantasy.ProviderOptions(toolCall.ProviderMetadata),
	}
}

func toolResultContentToPart(toolResult fantasy.ToolResultContent) fantasy.ToolResultPart {
	return fantasy.ToolResultPart{
		ToolCallID:       toolResult.ToolCallID,
		Output:           toolResult.Result,
		ProviderExecuted: toolResult.ProviderExecuted,
		ProviderOptions:  fantasy.ProviderOptions(toolResult.ProviderMetadata),
	}
}

func TestStreamSilenceGuard_DisarmAndFireRace(t *testing.T) {
	t.Parallel()

	for range 128 {
		var cancels atomic.Int32
		guard := newStreamSilenceGuard(quartz.NewReal(), time.Hour, func(err error) {
			if errors.Is(err, errStreamSilenceTimeout) {
				cancels.Add(1)
			}
		})

		start := make(chan struct{})
		var wg sync.WaitGroup
		wg.Add(2)

		go func() {
			defer wg.Done()
			<-start
			guard.onTimeout()
		}()

		go func() {
			defer wg.Done()
			<-start
			guard.Disarm()
		}()

		close(start)
		wg.Wait()

		guard.onTimeout()
		guard.Disarm()

		require.LessOrEqual(t, cancels.Load(), int32(1))
	}
}

func TestStreamSilenceGuard_DisarmPreservesPermanentError(t *testing.T) {
	t.Parallel()

	attemptCtx, cancelAttempt := context.WithCancelCause(context.Background())
	defer cancelAttempt(nil)

	guard := newStreamSilenceGuard(quartz.NewReal(), time.Hour, cancelAttempt)
	guard.Disarm()
	guard.onTimeout()

	classified := chaterror.Classify(classifyStreamSilenceTimeout(
		attemptCtx,
		"openai",
		xerrors.New("invalid model"),
	))
	require.Equal(t, codersdk.ChatErrorKindConfig, classified.Kind)
	require.False(t, classified.Retryable)
	require.Nil(t, context.Cause(attemptCtx))
}

func TestGenerateAssistant_ProviderContextSurvivesStreamError(t *testing.T) {
	t.Parallel()

	model := &chattest.FakeModel{
		ProviderName: "openai",
		ModelName:    "test-model",
		StreamFn: func(_ context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
			return nil, xerrors.New("upstream returned status 400")
		},
	}

	_, err := GenerateAssistant(context.Background(), GenerateAssistantOptions{
		Model: model,
		Messages: []fantasy.Message{
			textMessage(fantasy.MessageRoleUser, "hello"),
		},
	})
	require.Error(t, err)
	classified := chaterror.Classify(err)
	require.Equal(t, "openai", classified.Provider)
	require.Equal(t, "OpenAI returned an unexpected error.", classified.Message)
}

func TestGenerateAssistant_HTTP2TransportErrorClassifiedAsRetryableTimeout(t *testing.T) {
	t.Parallel()

	for _, provider := range []string{"anthropic", "openai"} {
		provider := provider
		t.Run(provider, func(t *testing.T) {
			t.Parallel()

			model := &chattest.FakeModel{
				ProviderName: provider,
				ModelName:    "test-model",
				StreamFn: func(_ context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
					return nil, xerrors.New("http2: client connection force closed via ClientConn.Close")
				},
			}

			_, err := GenerateAssistant(context.Background(), GenerateAssistantOptions{
				Model: model,
			})
			require.Error(t, err)
			classified := chaterror.Classify(err)
			require.Equal(t, codersdk.ChatErrorKindTimeout, classified.Kind)
			require.Equal(t, provider, classified.Provider)
			require.True(t, classified.Retryable)
		})
	}
}

func TestGenerateAssistant_StreamSilenceTimeoutRetryClassification(t *testing.T) {
	t.Parallel()

	t.Run("timeout while opening stream", func(t *testing.T) {
		t.Parallel()

		ctx := testutil.Context(t, testutil.WaitLong)
		const silenceTimeout = 5 * time.Millisecond
		clock := quartz.NewMock(t)
		trap := clock.Trap().AfterFunc(streamSilenceGuardTimerTag)
		defer trap.Close()
		var calls atomic.Int32
		model := &chattest.FakeModel{
			ProviderName: "openai",
			ModelName:    "test-model",
			StreamFn: func(ctx context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
				if calls.Add(1) == 1 {
					<-ctx.Done()
					return nil, ctx.Err()
				}
				return streamFromParts([]fantasy.StreamPart{{
					Type:         fantasy.StreamPartTypeFinish,
					FinishReason: fantasy.FinishReasonStop,
				}}), nil
			},
		}
		done := make(chan error, 1)
		go func() {
			_, err := GenerateAssistant(context.Background(), GenerateAssistantOptions{
				Model:                model,
				Clock:                clock,
				StreamSilenceTimeout: silenceTimeout,
			})
			done <- err
		}()

		trap.MustWait(ctx).MustRelease(ctx)
		_, waiter := clock.AdvanceNext()
		waiter.MustWait(ctx)
		require.Error(t, <-done)
		require.Equal(t, int32(1), calls.Load())
	})

	t.Run("timeout before first part", func(t *testing.T) {
		t.Parallel()

		ctx := testutil.Context(t, testutil.WaitLong)
		const silenceTimeout = 5 * time.Millisecond
		clock := quartz.NewMock(t)
		trap := clock.Trap().AfterFunc(streamSilenceGuardTimerTag)
		defer trap.Close()
		var calls atomic.Int32
		model := &chattest.FakeModel{
			ProviderName: "openai",
			ModelName:    "test-model",
			StreamFn: func(ctx context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
				calls.Add(1)
				return func(yield func(fantasy.StreamPart) bool) {
					<-ctx.Done()
					yield(fantasy.StreamPart{Type: fantasy.StreamPartTypeError, Error: ctx.Err()})
				}, nil
			},
		}
		done := make(chan error, 1)
		go func() {
			_, err := GenerateAssistant(context.Background(), GenerateAssistantOptions{
				Model:                model,
				Clock:                clock,
				StreamSilenceTimeout: silenceTimeout,
			})
			done <- err
		}()

		trap.MustWait(ctx).MustRelease(ctx)
		_, waiter := clock.AdvanceNext()
		waiter.MustWait(ctx)
		err := <-done
		require.Error(t, err)
		classified := chaterror.Classify(err)
		require.Equal(t, codersdk.ChatErrorKindStreamSilenceTimeout, classified.Kind)
		require.Equal(t, "openai", classified.Provider)
		require.True(t, classified.Retryable)
		require.Equal(t, int32(1), calls.Load())
	})

	t.Run("first part disarms timeout", func(t *testing.T) {
		t.Parallel()

		ctx := testutil.Context(t, testutil.WaitLong)
		const silenceTimeout = 5 * time.Millisecond
		clock := quartz.NewMock(t)
		trap := clock.Trap().AfterFunc(streamSilenceGuardTimerTag)
		defer trap.Close()
		var calls atomic.Int32
		continueStream := make(chan struct{})
		model := &chattest.FakeModel{
			ProviderName: "openai",
			ModelName:    "test-model",
			StreamFn: func(ctx context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
				calls.Add(1)
				return func(yield func(fantasy.StreamPart) bool) {
					if !yield(fantasy.StreamPart{Type: fantasy.StreamPartTypeTextStart, ID: "text-1"}) {
						return
					}
					select {
					case <-continueStream:
					case <-ctx.Done():
						yield(fantasy.StreamPart{Type: fantasy.StreamPartTypeError, Error: ctx.Err()})
						return
					}
					yield(fantasy.StreamPart{Type: fantasy.StreamPartTypeTextDelta, ID: "text-1", Delta: "done"})
					yield(fantasy.StreamPart{Type: fantasy.StreamPartTypeTextEnd, ID: "text-1"})
					yield(fantasy.StreamPart{Type: fantasy.StreamPartTypeFinish, FinishReason: fantasy.FinishReasonStop})
				}, nil
			},
		}
		done := make(chan error, 1)
		go func() {
			_, err := GenerateAssistant(context.Background(), GenerateAssistantOptions{
				Model:                model,
				Clock:                clock,
				StreamSilenceTimeout: silenceTimeout,
			})
			done <- err
		}()

		trap.MustWait(ctx).MustRelease(ctx)
		close(continueStream)
		require.NoError(t, <-done)
		require.Equal(t, int32(1), calls.Load())
	})

	t.Run("silent stream close after timeout", func(t *testing.T) {
		t.Parallel()

		ctx := testutil.Context(t, testutil.WaitLong)
		const silenceTimeout = 5 * time.Millisecond
		clock := quartz.NewMock(t)
		trap := clock.Trap().AfterFunc(streamSilenceGuardTimerTag)
		defer trap.Close()
		var calls atomic.Int32
		model := &chattest.FakeModel{
			ProviderName: "openai",
			ModelName:    "test-model",
			StreamFn: func(ctx context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
				calls.Add(1)
				return func(func(fantasy.StreamPart) bool) {
					<-ctx.Done()
				}, nil
			},
		}
		done := make(chan error, 1)
		go func() {
			_, err := GenerateAssistant(context.Background(), GenerateAssistantOptions{
				Model:                model,
				Clock:                clock,
				StreamSilenceTimeout: silenceTimeout,
			})
			done <- err
		}()

		trap.MustWait(ctx).MustRelease(ctx)
		_, waiter := clock.AdvanceNext()
		waiter.MustWait(ctx)
		err := <-done
		require.Error(t, err)
		classified := chaterror.Classify(err)
		require.Equal(t, codersdk.ChatErrorKindStreamSilenceTimeout, classified.Kind)
		require.Equal(t, int32(1), calls.Load())
	})
}

func TestGenerateAssistant_PanicInPublishMessagePartReleasesAttempt(t *testing.T) {
	t.Parallel()

	attemptReleased := make(chan struct{})
	model := &chattest.FakeModel{
		ProviderName: "openai",
		ModelName:    "test-model",
		StreamFn: func(ctx context.Context, _ fantasy.Call) (fantasy.StreamResponse, error) {
			go func() {
				<-ctx.Done()
				close(attemptReleased)
			}()
			return streamFromParts([]fantasy.StreamPart{
				{Type: fantasy.StreamPartTypeTextStart, ID: "text-1"},
				{Type: fantasy.StreamPartTypeTextDelta, ID: "text-1", Delta: "boom"},
			}), nil
		},
	}

	defer func() {
		r := recover()
		require.NotNil(t, r)
		select {
		case <-attemptReleased:
		case <-time.After(time.Second):
			t.Fatal("attempt context was not released after panic")
		}
	}()

	_, _ = GenerateAssistant(context.Background(), GenerateAssistantOptions{
		Model: model,
		PublishMessagePart: func(codersdk.ChatMessageRole, codersdk.ChatMessagePart) {
			panic("publish panic")
		},
	})

	t.Fatal("expected GenerateAssistant to panic")
}

func requireToolResultErrorMessage(
	t *testing.T,
	result fantasy.ToolResultContent,
	expected string,
) {
	t.Helper()

	output, ok := result.Result.(fantasy.ToolResultOutputContentError)
	require.Truef(t, ok, "expected error tool result, got %T", result.Result)
	require.Error(t, output.Error)
	require.Equal(t, expected, output.Error.Error())
}

func streamFromParts(parts []fantasy.StreamPart) fantasy.StreamResponse {
	return iter.Seq[fantasy.StreamPart](func(yield func(fantasy.StreamPart) bool) {
		for _, part := range parts {
			if !yield(part) {
				return
			}
		}
	})
}

func textMessage(role fantasy.MessageRole, text string) fantasy.Message {
	return fantasy.Message{
		Role: role,
		Content: []fantasy.MessagePart{
			fantasy.TextPart{Text: text},
		},
	}
}

func requireTextContent(t *testing.T, content []fantasy.Content, text string) fantasy.TextContent {
	t.Helper()

	for _, block := range content {
		textContent, ok := fantasy.AsContentType[fantasy.TextContent](block)
		if ok && textContent.Text == text {
			return textContent
		}
	}
	t.Fatalf("missing text content %q", text)
	return fantasy.TextContent{}
}

func TestExclusiveToolPolicy_MixedBatchErrors(t *testing.T) {
	t.Parallel()

	results, violated := applyExclusiveToolPolicy(
		[]fantasy.ToolCallContent{
			{ToolCallID: "advisor-1", ToolName: "advisor", Input: `{}`},
			{ToolCallID: "read-1", ToolName: "read_file", Input: `{"path":"main.go"}`},
		},
		map[string]bool{"advisor": true},
		NopMetrics(),
		"fake",
		"",
	)

	require.True(t, violated)
	require.Len(t, results, 2)
	require.Equal(t, "advisor-1", results[0].ToolCallID)
	require.Equal(t, "read-1", results[1].ToolCallID)
	requireToolResultErrorMessage(
		t,
		results[0],
		"advisor must be called alone, without other tools in the same batch. Retry with only the advisor call.",
	)
	requireToolResultErrorMessage(
		t,
		results[1],
		"this tool was skipped because advisor must run alone in its batch. Retry your tool calls without advisor, or call advisor separately first.",
	)
}

func TestApplyExclusiveToolPolicy_RecordsErrorMetrics(t *testing.T) {
	t.Parallel()

	reg := prometheus.NewPedanticRegistry()
	m := NewMetrics(reg)

	_, violated := applyExclusiveToolPolicy(
		[]fantasy.ToolCallContent{
			{ToolCallID: "advisor-1", ToolName: "advisor", Input: `{}`},
			{ToolCallID: "read-1", ToolName: "read_file", Input: `{"path":"main.go"}`},
		},
		map[string]bool{"advisor": true},
		m,
		"fake",
		"claude-test",
	)
	require.True(t, violated)

	require.Equal(t, 1.0, promtestutil.ToFloat64(
		m.ToolErrorsTotal.WithLabelValues("fake", "claude-test", "advisor"),
	))
	require.Equal(t, 1.0, promtestutil.ToFloat64(
		m.ToolErrorsTotal.WithLabelValues("fake", "claude-test", "read_file"),
	))
}

func TestExclusiveToolPolicy_MultipleExclusive(t *testing.T) {
	t.Parallel()

	results, violated := applyExclusiveToolPolicy(
		[]fantasy.ToolCallContent{
			{ToolCallID: "advisor-1", ToolName: "advisor", Input: `{}`},
			{ToolCallID: "advisor-2", ToolName: "advisor", Input: `{"mode":"second-opinion"}`},
		},
		map[string]bool{"advisor": true},
		NopMetrics(),
		"fake",
		"",
	)

	require.True(t, violated)
	require.Len(t, results, 2)
	requireToolResultErrorMessage(
		t,
		results[0],
		"advisor must be called alone, without other tools in the same batch. Retry with only the advisor call.",
	)
	requireToolResultErrorMessage(
		t,
		results[1],
		"advisor must be called alone, without other tools in the same batch. Retry with only the advisor call.",
	)
}

func TestSanitizeAnthropicProviderToolContent(t *testing.T) {
	t.Parallel()

	providerCall := func(id, name, input string) fantasy.ToolCallContent {
		return fantasy.ToolCallContent{
			ToolCallID:       id,
			ToolName:         name,
			Input:            input,
			ProviderExecuted: true,
		}
	}
	providerResult := func(id, name string) fantasy.ToolResultContent {
		return fantasy.ToolResultContent{
			ToolCallID:       id,
			ToolName:         name,
			ProviderExecuted: true,
			ProviderMetadata: validWebSearchProviderMetadataForTest(),
			Result:           fantasy.ToolResultOutputContentText{Text: "ok"},
		}
	}
	localCall := func(id, name string) fantasy.ToolCallContent {
		return fantasy.ToolCallContent{
			ToolCallID: id,
			ToolName:   name,
			Input:      `{}`,
		}
	}
	localResult := func(id, name string) fantasy.ToolResultContent {
		return fantasy.ToolResultContent{
			ToolCallID: id,
			ToolName:   name,
			Result:     fantasy.ToolResultOutputContentText{Text: "ok"},
		}
	}
	type contentSummary struct {
		providerCalls   []string
		providerResults []string
		localCalls      []string
		localResults    []string
	}
	summarizeContent := func(content []fantasy.Content) contentSummary {
		var summary contentSummary
		for _, block := range content {
			if toolCall, ok := safeToolCallContent(block); ok {
				if toolCall.ProviderExecuted {
					summary.providerCalls = append(summary.providerCalls, toolCall.ToolCallID)
				} else {
					summary.localCalls = append(summary.localCalls, toolCall.ToolCallID)
				}
				continue
			}
			if toolResult, ok := safeToolResultContent(block); ok {
				if toolResult.ProviderExecuted {
					summary.providerResults = append(summary.providerResults, toolResult.ToolCallID)
				} else {
					summary.localResults = append(summary.localResults, toolResult.ToolCallID)
				}
			}
		}
		return summary
	}
	assertProviderHistoryValid := func(t *testing.T, content []fantasy.Content) {
		t.Helper()

		parts := make([]fantasy.MessagePart, 0)
		for _, block := range content {
			if toolCall, ok := safeToolCallContent(block); ok && toolCall.ProviderExecuted {
				parts = append(parts, toolCallContentToPart(toolCall))
				continue
			}
			if toolResult, ok := safeToolResultContent(block); ok && toolResult.ProviderExecuted {
				parts = append(parts, toolResultContentToPart(toolResult))
			}
		}
		if len(parts) == 0 {
			return
		}
		require.Empty(t, chatsanitize.ValidateAnthropicProviderToolHistory([]fantasy.Message{
			{
				Role:    fantasy.MessageRoleAssistant,
				Content: parts,
			},
		}))
	}

	metadataCall := providerCall("ws-meta", "web_search", `{"query":"coder"}`)
	metadataCall.ProviderMetadata = fantasy.ProviderMetadata{fantasyanthropic.Name: nil}
	metadataResult := providerResult("ws-meta", "web_search")
	metadataResult.ProviderMetadata = fantasy.ProviderMetadata{fantasyanthropic.Name: nil}
	pointerCall := providerCall("ws-pointer", "web_search", `{"query":"coder"}`)
	var nilToolCall *fantasy.ToolCallContent

	testCases := []struct {
		name               string
		provider           string
		content            []fantasy.Content
		wantSummary        contentSummary
		wantRemovedCalls   int
		wantRemovedResults int
		wantTexts          []string
		validateAnthropic  bool
	}{
		{
			name:     "orphan provider result textified",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				fantasy.TextContent{Text: "keep"},
				providerResult("ws-1", "web_search"),
			},
			wantRemovedResults: 1,
			wantTexts:          []string{"keep", "ok"},
			validateAnthropic:  true,
		},
		{
			name:     "result before call removes both provider blocks",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerResult("ws-1", "web_search"),
				providerCall("ws-1", "web_search", `{"query":"coder"}`),
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "valid web search pair preserved",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("ws-1", "web_search", `{"query":"coder"}`),
				providerResult("ws-1", "web_search"),
				fantasy.TextContent{Text: "search done"},
			},
			wantSummary: contentSummary{
				providerCalls:   []string{"ws-1"},
				providerResults: []string{"ws-1"},
			},
			wantTexts:         []string{"search done"},
			validateAnthropic: true,
		},
		{
			name:     "invalid JSON provider call drops pair",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("ws-1", "web_search", `{`),
				providerResult("ws-1", "web_search"),
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "empty ID provider call drops pair",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("", "web_search", `{"query":"coder"}`),
				providerResult("", "web_search"),
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "empty tool name provider call drops pair",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("ws-empty", "", `{"query":"coder"}`),
				providerResult("ws-empty", ""),
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "non web search provider pair drops through serializable helper",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("code-1", "code_execution", `{"code":"print(1)"}`),
				providerResult("code-1", "code_execution"),
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "mismatched provider result tool name drops pair",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("ws-mismatch", "web_search", `{"query":"coder"}`),
				providerResult("ws-mismatch", "code_execution"),
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "duplicate provider IDs drop all provider content for ID",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("dup-1", "web_search", `{"query":"coder"}`),
				providerResult("dup-1", "web_search"),
				providerCall("dup-1", "web_search", `{"query":"coder"}`),
			},
			wantRemovedCalls:   2,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "mismatched provider flags remove only provider side",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				providerCall("mix-1", "web_search", `{"query":"coder"}`),
				localResult("mix-1", "web_search"),
				localCall("mix-2", "read_file"),
				providerResult("mix-2", "web_search"),
			},
			wantSummary: contentSummary{
				localCalls:   []string{"mix-2"},
				localResults: []string{"mix-1"},
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "malformed provider metadata textifies result",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				metadataCall,
				metadataResult,
			},
			wantRemovedCalls:   1,
			wantRemovedResults: 1,
			wantTexts:          []string{"ok"},
			validateAnthropic:  true,
		},
		{
			name:     "pointer and nil pointer variants are handled safely",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				nilToolCall,
				&pointerCall,
				providerResult("ws-pointer", "web_search"),
			},
			wantSummary: contentSummary{
				providerCalls:   []string{"ws-pointer"},
				providerResults: []string{"ws-pointer"},
			},
			validateAnthropic: true,
		},
		{
			name:     "local tool content is unchanged",
			provider: fantasyanthropic.Name,
			content: []fantasy.Content{
				localCall("tc-1", "read_file"),
				localResult("tc-1", "read_file"),
			},
			wantSummary: contentSummary{
				localCalls:   []string{"tc-1"},
				localResults: []string{"tc-1"},
			},
			validateAnthropic: true,
		},
		{
			name:     "non Anthropic provider content is unchanged",
			provider: "fake",
			content: []fantasy.Content{
				providerCall("ws-1", "web_search", `{"query":"coder"}`),
			},
			wantSummary: contentSummary{
				providerCalls: []string{"ws-1"},
			},
		},
	}

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

			sanitized, stats := chatsanitize.SanitizeAnthropicProviderToolContent(tc.provider, tc.content)
			require.Equal(t, tc.wantRemovedCalls, stats.RemovedToolCalls)
			require.Equal(t, tc.wantRemovedResults, stats.RemovedToolResults)
			require.Zero(t, stats.DroppedMessages)

			summary := summarizeContent(sanitized)
			assert.ElementsMatch(t, tc.wantSummary.providerCalls, summary.providerCalls)
			assert.ElementsMatch(t, tc.wantSummary.providerResults, summary.providerResults)
			assert.ElementsMatch(t, tc.wantSummary.localCalls, summary.localCalls)
			assert.ElementsMatch(t, tc.wantSummary.localResults, summary.localResults)
			for _, text := range tc.wantTexts {
				requireTextContent(t, sanitized, text)
			}
			if tc.validateAnthropic {
				assertProviderHistoryValid(t, sanitized)
			}
		})
	}
}

func TestExecuteSingleTool_MediaBase64Encoding(t *testing.T) {
	t.Parallel()

	originalBytes := []byte{0xFF, 0xD8, 0xFF, 0xE0, 0x00, 0x10}
	metrics := NewMetrics(prometheus.NewRegistry())
	logger := slog.Make()

	t.Run("EncodesRawBytesToBase64", func(t *testing.T) {
		t.Parallel()

		tool := fantasy.NewAgentTool(
			"screenshot",
			"takes a screenshot",
			func(_ context.Context, _ struct{}, _ fantasy.ToolCall) (fantasy.ToolResponse, error) {
				return fantasy.ToolResponse{
					Type:      "image",
					Data:      originalBytes,
					MediaType: "image/jpeg",
				}, nil
			},
		)

		toolMap := map[string]fantasy.AgentTool{
			"screenshot": tool,
		}
		tc := fantasy.ToolCallContent{
			ToolCallID: "call-1",
			ToolName:   "screenshot",
			Input:      "{}",
		}

		result := executeSingleTool(
			context.Background(),
			toolMap,
			tc,
			metrics,
			logger,
			"fake", "fake-model",
			map[string]bool{},
			[]string{"screenshot"},
			map[string]struct{}{},
			nil,
		)

		media, ok := result.Result.(fantasy.ToolResultOutputContentMedia)
		require.True(t, ok, "expected ToolResultOutputContentMedia")
		require.Equal(t, "image/jpeg", media.MediaType)

		decoded, err := base64.StdEncoding.DecodeString(media.Data)
		require.NoError(t, err, "Data should be valid base64")
		require.Equal(t, originalBytes, decoded)
	})

	t.Run("SanitizesInvalidUTF8InContent", func(t *testing.T) {
		t.Parallel()

		tool := fantasy.NewAgentTool(
			"screenshot",
			"takes a screenshot",
			func(_ context.Context, _ struct{}, _ fantasy.ToolCall) (fantasy.ToolResponse, error) {
				return fantasy.ToolResponse{
					Type:      "image",
					Data:      originalBytes,
					MediaType: "image/png",
					Content:   "hello\xffworld",
				}, nil
			},
		)

		toolMap := map[string]fantasy.AgentTool{
			"screenshot": tool,
		}
		tc := fantasy.ToolCallContent{
			ToolCallID: "call-2",
			ToolName:   "screenshot",
			Input:      "{}",
		}

		result := executeSingleTool(
			context.Background(),
			toolMap,
			tc,
			metrics,
			logger,
			"fake", "fake-model",
			map[string]bool{},
			[]string{"screenshot"},
			map[string]struct{}{},
			nil,
		)

		media, ok := result.Result.(fantasy.ToolResultOutputContentMedia)
		require.True(t, ok, "expected ToolResultOutputContentMedia")
		require.True(t, utf8.ValidString(media.Text), "Text should be valid UTF-8")
		require.Contains(t, media.Text, "hello")
		require.Contains(t, media.Text, "world")
	})

	t.Run("SanitizesInvalidUTF8InTextResult", func(t *testing.T) {
		t.Parallel()

		tool := fantasy.NewAgentTool(
			"echo",
			"echoes input",
			func(_ context.Context, _ struct{}, _ fantasy.ToolCall) (fantasy.ToolResponse, error) {
				return fantasy.ToolResponse{
					Content: "hello\xffworld",
				}, nil
			},
		)

		toolMap := map[string]fantasy.AgentTool{
			"echo": tool,
		}
		tc := fantasy.ToolCallContent{
			ToolCallID: "call-3",
			ToolName:   "echo",
			Input:      "{}",
		}

		result := executeSingleTool(
			context.Background(),
			toolMap,
			tc,
			metrics,
			logger,
			"fake", "fake-model",
			map[string]bool{},
			[]string{"echo"},
			map[string]struct{}{},
			nil,
		)

		textOutput, ok := result.Result.(fantasy.ToolResultOutputContentText)
		require.True(t, ok, "expected ToolResultOutputContentText, got %T", result.Result)
		require.True(t, utf8.ValidString(textOutput.Text), "Text should be valid UTF-8")
		require.Contains(t, textOutput.Text, "hello")
		require.Contains(t, textOutput.Text, "world")
	})
}