package service

import (
	"testing"

	"github.com/stretchr/testify/require"
)

func TestApplyCodexOAuthTransform_ToolContinuationPreservesInput(t *testing.T) {
	// 续链场景：保留 item_reference 与 id，但不再强制 store=true。

	reqBody := map[string]any{
		"model": "gpt-5.2",
		"input": []any{
			map[string]any{"type": "item_reference", "id": "ref1", "text": "x"},
			map[string]any{"type": "function_call_output", "call_id": "call_1", "output": "ok", "id": "o1"},
		},
		"tool_choice": "auto",
	}

	applyCodexOAuthTransform(reqBody, false, false)

	// 未显式设置 store=true，默认为 false。
	store, ok := reqBody["store"].(bool)
	require.True(t, ok)
	require.False(t, store)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 2)

	// 校验 input[0] 为 map，避免断言失败导致测试中断。
	first, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "item_reference", first["type"])
	require.Equal(t, "ref1", first["id"])

	// 校验 input[1] 为 map，确保后续字段断言安全。
	second, ok := input[1].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "o1", second["id"])
	require.Equal(t, "fc1", second["call_id"])
}

func TestApplyCodexOAuthTransform_ToolContinuationPreservesNativeMessageAndReasoningIDs(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.2",
		"input": []any{
			map[string]any{"type": "message", "id": "msg_0", "role": "user", "content": "hi"},
			map[string]any{"type": "item_reference", "id": "rs_123"},
		},
		"tool_choice": "auto",
	}

	applyCodexOAuthTransform(reqBody, false, false)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 2)

	first, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "msg_0", first["id"])

	second, ok := input[1].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "rs_123", second["id"])
}

func TestApplyCodexOAuthTransform_ToolContinuationNormalizesToolReferenceIDsOnly(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.2",
		"input": []any{
			map[string]any{"type": "item_reference", "id": "call_1"},
			map[string]any{"type": "function_call_output", "call_id": "call_1", "output": "ok"},
		},
		"tool_choice": "auto",
	}

	applyCodexOAuthTransform(reqBody, false, false)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 2)

	first, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "fc1", first["id"])

	second, ok := input[1].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "fc1", second["call_id"])
}

func TestApplyCodexOAuthTransform_ToolSearchOutputPreservesCallID(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.2",
		"input": []any{
			map[string]any{"type": "tool_search_output", "call_id": "call_1", "output": "ok"},
		},
	}

	applyCodexOAuthTransform(reqBody, false, false)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 1)

	first, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "tool_search_output", first["type"])
	require.Equal(t, "fc1", first["call_id"])
}

func TestApplyCodexOAuthTransform_CustomAndMCPToolOutputsPreserveCallID(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.2",
		"input": []any{
			map[string]any{"type": "custom_tool_call_output", "call_id": "call_custom", "output": "ok"},
			map[string]any{"type": "mcp_tool_call_output", "call_id": "call_mcp", "output": "ok"},
		},
	}

	applyCodexOAuthTransform(reqBody, false, false)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 2)

	first, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "fccustom", first["call_id"])

	second, ok := input[1].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "fcmcp", second["call_id"])
}

func TestApplyCodexOAuthTransform_ImageAndWebSearchCallsDoNotGainCallID(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.2",
		"input": []any{
			map[string]any{"type": "image_generation_call", "id": "ig_123", "status": "completed"},
			map[string]any{"type": "web_search_call", "call_id": "call_bad", "status": "completed"},
		},
		"tool_choice": "auto",
	}

	applyCodexOAuthTransform(reqBody, false, false)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 2)

	first, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "ig_123", first["id"])
	_, hasCallID := first["call_id"]
	require.False(t, hasCallID)

	second, ok := input[1].(map[string]any)
	require.True(t, ok)
	_, hasCallID = second["call_id"]
	require.False(t, hasCallID)
}

func TestApplyCodexOAuthTransform_ExplicitStoreFalsePreserved(t *testing.T) {
	// 续链场景：显式 store=false 不再强制为 true，保持 false。

	reqBody := map[string]any{
		"model": "gpt-5.1",
		"store": false,
		"input": []any{
			map[string]any{"type": "function_call_output", "call_id": "call_1"},
		},
		"tool_choice": "auto",
	}

	applyCodexOAuthTransform(reqBody, false, false)

	store, ok := reqBody["store"].(bool)
	require.True(t, ok)
	require.False(t, store)
}

func TestApplyCodexOAuthTransform_ExplicitStoreTrueForcedFalse(t *testing.T) {
	// 显式 store=true 也会强制为 false。

	reqBody := map[string]any{
		"model": "gpt-5.1",
		"store": true,
		"input": []any{
			map[string]any{"type": "function_call_output", "call_id": "call_1"},
		},
		"tool_choice": "auto",
	}

	applyCodexOAuthTransform(reqBody, false, false)

	store, ok := reqBody["store"].(bool)
	require.True(t, ok)
	require.False(t, store)
}

func TestApplyCodexOAuthTransform_CompactForcesNonStreaming(t *testing.T) {
	reqBody := map[string]any{
		"model":  "gpt-5.1-codex",
		"store":  true,
		"stream": true,
	}

	result := applyCodexOAuthTransform(reqBody, true, true)

	_, hasStore := reqBody["store"]
	require.False(t, hasStore)
	_, hasStream := reqBody["stream"]
	require.False(t, hasStream)
	require.True(t, result.Modified)
}

func TestApplyCodexOAuthTransform_NonContinuationDefaultsStoreFalseAndStripsIDs(t *testing.T) {
	// 非续链场景：未设置 store 时默认 false，并移除 input 中的 id。

	reqBody := map[string]any{
		"model": "gpt-5.1",
		"input": []any{
			map[string]any{"type": "text", "id": "t1", "text": "hi"},
		},
	}

	applyCodexOAuthTransform(reqBody, false, false)

	store, ok := reqBody["store"].(bool)
	require.True(t, ok)
	require.False(t, store)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 1)
	// 校验 input[0] 为 map，避免类型不匹配触发 errcheck。
	item, ok := input[0].(map[string]any)
	require.True(t, ok)
	_, hasID := item["id"]
	require.False(t, hasID)
}

func TestFilterCodexInput_RemovesItemReferenceWhenNotPreserved(t *testing.T) {
	input := []any{
		map[string]any{"type": "item_reference", "id": "ref1"},
		map[string]any{"type": "text", "id": "t1", "text": "hi"},
	}

	filtered := filterCodexInput(input, false)
	require.Len(t, filtered, 1)
	// 校验 filtered[0] 为 map，确保字段检查可靠。
	item, ok := filtered[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "text", item["type"])
	_, hasID := item["id"]
	require.False(t, hasID)
}

func TestApplyCodexOAuthTransform_NormalizeCodexTools_PreservesResponsesFunctionTools(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.1",
		"tools": []any{
			map[string]any{
				"type":        "function",
				"name":        "bash",
				"description": "desc",
				"parameters":  map[string]any{"type": "object"},
			},
			map[string]any{
				"type":     "function",
				"function": nil,
			},
		},
	}

	applyCodexOAuthTransform(reqBody, false, false)

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	require.Len(t, tools, 1)

	first, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "function", first["type"])
	require.Equal(t, "bash", first["name"])
}

func TestNormalizeOpenAIResponsesImageGenerationTools_RewritesLegacyFields(t *testing.T) {
	reqBody := map[string]any{
		"tools": []any{
			map[string]any{
				"type":        "image_generation",
				"format":      "png",
				"compression": 60,
			},
		},
	}

	modified := normalizeOpenAIResponsesImageGenerationTools(reqBody)
	require.True(t, modified)

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	first, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "png", first["output_format"])
	require.Equal(t, 60, first["output_compression"])
	_, hasFormat := first["format"]
	require.False(t, hasFormat)
	_, hasCompression := first["compression"]
	require.False(t, hasCompression)
}

func TestEnsureOpenAIResponsesImageGenerationTool_NoTools(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.4",
		"input": "draw a cat",
	}

	modified := ensureOpenAIResponsesImageGenerationTool(reqBody)
	require.True(t, modified)

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	require.Len(t, tools, 1)
	tool, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "image_generation", tool["type"])
	require.Equal(t, "png", tool["output_format"])
}

func TestEnsureOpenAIResponsesImageGenerationTool_AppendsToExistingTools(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.4",
		"tools": []any{
			map[string]any{"type": "web_search"},
		},
	}

	modified := ensureOpenAIResponsesImageGenerationTool(reqBody)
	require.True(t, modified)

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	require.Len(t, tools, 2)
	first, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "web_search", first["type"])
	second, ok := tools[1].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "image_generation", second["type"])
	require.Equal(t, "png", second["output_format"])
}

func TestEnsureOpenAIResponsesImageGenerationTool_PreservesExistingImageTool(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.4",
		"tools": []any{
			map[string]any{"type": "image_generation", "output_format": "webp"},
			map[string]any{"type": "web_search"},
		},
	}

	modified := ensureOpenAIResponsesImageGenerationTool(reqBody)
	require.False(t, modified)

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	require.Len(t, tools, 2)
	tool, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "webp", tool["output_format"])
}

func TestApplyCodexImageGenerationBridgeInstructions_AppendsBridgeOnce(t *testing.T) {
	reqBody := map[string]any{
		"instructions": "existing instructions",
		"tools": []any{
			map[string]any{"type": "image_generation", "output_format": "png"},
		},
	}

	modified := applyCodexImageGenerationBridgeInstructions(reqBody)
	require.True(t, modified)

	instructions, ok := reqBody["instructions"].(string)
	require.True(t, ok)
	require.Contains(t, instructions, "existing instructions")
	require.Contains(t, instructions, codexImageGenerationBridgeMarker)
	require.Contains(t, instructions, "Responses native `image_generation` tool")

	modified = applyCodexImageGenerationBridgeInstructions(reqBody)
	require.False(t, modified)
}

func TestApplyCodexImageGenerationBridgeInstructions_SkipsWithoutImageTool(t *testing.T) {
	reqBody := map[string]any{
		"instructions": "existing instructions",
		"tools": []any{
			map[string]any{"type": "web_search"},
		},
	}

	modified := applyCodexImageGenerationBridgeInstructions(reqBody)
	require.False(t, modified)
	require.Equal(t, "existing instructions", reqBody["instructions"])
}

func TestNormalizeOpenAIResponsesImageOnlyModel_BuildsImageToolRequest(t *testing.T) {
	reqBody := map[string]any{
		"model":         "gpt-image-2",
		"prompt":        "draw a cat",
		"size":          "1024x1024",
		"output_format": "png",
	}

	modified := normalizeOpenAIResponsesImageOnlyModel(reqBody)
	require.True(t, modified)
	require.Equal(t, openAIImagesResponsesMainModel, reqBody["model"])
	require.Equal(t, "draw a cat", reqBody["input"])
	_, hasPrompt := reqBody["prompt"]
	require.False(t, hasPrompt)
	_, hasTopLevelSize := reqBody["size"]
	require.False(t, hasTopLevelSize)

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	require.Len(t, tools, 1)
	tool, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "image_generation", tool["type"])
	require.Equal(t, "gpt-image-2", tool["model"])
	require.Equal(t, "1024x1024", tool["size"])
	require.Equal(t, "png", tool["output_format"])

	choice, ok := reqBody["tool_choice"].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "image_generation", choice["type"])
}

func TestNormalizeOpenAIResponsesImageOnlyModel_PreservesExistingImageTool(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-image-2",
		"input": "draw a cat",
		"tools": []any{
			map[string]any{
				"type":  "image_generation",
				"model": "gpt-image-1.5",
			},
		},
		"tool_choice": "auto",
	}

	modified := normalizeOpenAIResponsesImageOnlyModel(reqBody)
	require.True(t, modified)
	require.Equal(t, openAIImagesResponsesMainModel, reqBody["model"])
	require.Equal(t, "auto", reqBody["tool_choice"])

	tools, ok := reqBody["tools"].([]any)
	require.True(t, ok)
	require.Len(t, tools, 1)
	tool, ok := tools[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "gpt-image-1.5", tool["model"])
}

func TestValidateOpenAIResponsesImageModel_RejectsImageOnlyModel(t *testing.T) {
	err := validateOpenAIResponsesImageModel(map[string]any{
		"tools": []any{
			map[string]any{"type": "image_generation"},
		},
	}, "gpt-image-2")

	require.ErrorContains(t, err, `/v1/responses image_generation requests require a Responses-capable text model`)
}

func TestApplyCodexOAuthTransform_EmptyInput(t *testing.T) {
	// 空 input 应保持为空且不触发异常。

	reqBody := map[string]any{
		"model": "gpt-5.1",
		"input": []any{},
	}

	applyCodexOAuthTransform(reqBody, false, false)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 0)
}

func TestNormalizeCodexModel_Gpt53(t *testing.T) {
	cases := map[string]string{
		"gpt-5.4":                   "gpt-5.4",
		"gpt-5.4-high":              "gpt-5.4",
		"gpt-5.4-chat-latest":       "gpt-5.4",
		"gpt 5.4":                   "gpt-5.4",
		"gpt-5.4-mini":              "gpt-5.4-mini",
		"gpt 5.4 mini":              "gpt-5.4-mini",
		"gpt-5.3":                   "gpt-5.3-codex",
		"gpt-5.3-codex":             "gpt-5.3-codex",
		"gpt-5.3-codex-xhigh":       "gpt-5.3-codex",
		"gpt-5.3-codex-spark":       "gpt-5.3-codex-spark",
		"gpt 5.3 codex spark":       "gpt-5.3-codex-spark",
		"gpt-5.3-codex-spark-high":  "gpt-5.3-codex-spark",
		"gpt-5.3-codex-spark-xhigh": "gpt-5.3-codex-spark",
		"gpt 5.3 codex":             "gpt-5.3-codex",
	}

	for input, expected := range cases {
		require.Equal(t, expected, normalizeCodexModel(input))
	}
}

func TestNormalizeCodexModel_RemovedModelsFallbackToSupportedTargets(t *testing.T) {
	cases := map[string]string{
		"":                   "gpt-5.4",
		"gpt-5":              "gpt-5.4",
		"gpt-5-mini":         "gpt-5.4",
		"gpt-5-nano":         "gpt-5.4",
		"gpt-5.1":            "gpt-5.4",
		"gpt-5.1-codex":      "gpt-5.3-codex",
		"gpt-5.1-codex-max":  "gpt-5.3-codex",
		"gpt-5.1-codex-mini": "gpt-5.3-codex",
		"gpt-5.2-codex":      "gpt-5.2",
		"codex-mini-latest":  "gpt-5.3-codex",
		"gpt-5-codex":        "gpt-5.3-codex",
	}

	for input, expected := range cases {
		require.Equal(t, expected, normalizeCodexModel(input))
	}
}

func TestApplyCodexOAuthTransform_PreservesBareSparkModel(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.3-codex-spark",
		"input": []any{},
	}

	result := applyCodexOAuthTransform(reqBody, false, false)

	require.Equal(t, "gpt-5.3-codex-spark", reqBody["model"])
	require.Equal(t, "gpt-5.3-codex-spark", result.NormalizedModel)
	store, ok := reqBody["store"].(bool)
	require.True(t, ok)
	require.False(t, store)
}

func TestApplyCodexOAuthTransform_TrimmedModelWithoutPolicyRewrite(t *testing.T) {
	reqBody := map[string]any{
		"model": "  gpt-5.3-codex-spark  ",
		"input": []any{},
	}

	result := applyCodexOAuthTransform(reqBody, false, false)

	require.Equal(t, "gpt-5.3-codex-spark", reqBody["model"])
	require.Equal(t, "gpt-5.3-codex-spark", result.NormalizedModel)
	require.True(t, result.Modified)
}

func TestApplyCodexOAuthTransform_CodexCLI_PreservesExistingInstructions(t *testing.T) {
	// Codex CLI 场景：已有 instructions 时不修改

	reqBody := map[string]any{
		"model":        "gpt-5.1",
		"instructions": "existing instructions",
	}

	result := applyCodexOAuthTransform(reqBody, true, false) // isCodexCLI=true

	instructions, ok := reqBody["instructions"].(string)
	require.True(t, ok)
	require.Equal(t, "existing instructions", instructions)
	// Modified 仍可能为 true（因为其他字段被修改），但 instructions 应保持不变
	_ = result
}

func TestApplyCodexOAuthTransform_CodexCLI_SuppliesDefaultWhenEmpty(t *testing.T) {
	// Codex CLI 场景：无 instructions 时补充默认值

	reqBody := map[string]any{
		"model": "gpt-5.1",
		// 没有 instructions 字段
	}

	result := applyCodexOAuthTransform(reqBody, true, false) // isCodexCLI=true

	instructions, ok := reqBody["instructions"].(string)
	require.True(t, ok)
	require.NotEmpty(t, instructions)
	require.True(t, result.Modified)
}

func TestApplyCodexOAuthTransform_NonCodexCLI_PreservesExistingInstructions(t *testing.T) {
	// 非 Codex CLI 场景：已有 instructions 时保留客户端的值，不再覆盖

	reqBody := map[string]any{
		"model":        "gpt-5.1",
		"instructions": "old instructions",
	}

	applyCodexOAuthTransform(reqBody, false, false) // isCodexCLI=false

	instructions, ok := reqBody["instructions"].(string)
	require.True(t, ok)
	require.Equal(t, "old instructions", instructions)
}

func TestApplyCodexOAuthTransform_StringInputConvertedToArray(t *testing.T) {
	reqBody := map[string]any{"model": "gpt-5.4", "input": "Hello, world!"}
	result := applyCodexOAuthTransform(reqBody, false, false)
	require.True(t, result.Modified)
	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 1)
	msg, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "message", msg["type"])
	require.Equal(t, "user", msg["role"])
	require.Equal(t, "Hello, world!", msg["content"])
}

func TestApplyCodexOAuthTransform_EmptyStringInputBecomesEmptyArray(t *testing.T) {
	reqBody := map[string]any{"model": "gpt-5.4", "input": ""}
	result := applyCodexOAuthTransform(reqBody, false, false)
	require.True(t, result.Modified)
	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 0)
}

func TestApplyCodexOAuthTransform_WhitespaceStringInputBecomesEmptyArray(t *testing.T) {
	reqBody := map[string]any{"model": "gpt-5.4", "input": "   "}
	result := applyCodexOAuthTransform(reqBody, false, false)
	require.True(t, result.Modified)
	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 0)
}

func TestApplyCodexOAuthTransform_StringInputWithToolsField(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.4",
		"input": "Run the tests",
		"tools": []any{map[string]any{"type": "function", "name": "bash"}},
	}
	applyCodexOAuthTransform(reqBody, false, false)
	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 1)
}

func TestExtractSystemMessagesFromInput(t *testing.T) {
	t.Run("no system messages", func(t *testing.T) {
		reqBody := map[string]any{
			"input": []any{
				map[string]any{"role": "user", "content": "hello"},
			},
		}
		result := extractSystemMessagesFromInput(reqBody)
		require.False(t, result)
		input, ok := reqBody["input"].([]any)
		require.True(t, ok)
		require.Len(t, input, 1)
		_, hasInstructions := reqBody["instructions"]
		require.False(t, hasInstructions)
	})

	t.Run("string content system message", func(t *testing.T) {
		reqBody := map[string]any{
			"input": []any{
				map[string]any{"role": "system", "content": "You are an assistant."},
				map[string]any{"role": "user", "content": "hello"},
			},
		}
		result := extractSystemMessagesFromInput(reqBody)
		require.True(t, result)
		input, ok := reqBody["input"].([]any)
		require.True(t, ok)
		require.Len(t, input, 1)
		msg, ok := input[0].(map[string]any)
		require.True(t, ok)
		require.Equal(t, "user", msg["role"])
		require.Equal(t, "You are an assistant.", reqBody["instructions"])
	})

	t.Run("array content system message", func(t *testing.T) {
		reqBody := map[string]any{
			"input": []any{
				map[string]any{
					"role": "system",
					"content": []any{
						map[string]any{"type": "text", "text": "Be helpful."},
					},
				},
			},
		}
		result := extractSystemMessagesFromInput(reqBody)
		require.True(t, result)
		require.Equal(t, "Be helpful.", reqBody["instructions"])
		input, ok := reqBody["input"].([]any)
		require.True(t, ok)
		require.Len(t, input, 0)
	})

	t.Run("multiple system messages concatenated", func(t *testing.T) {
		reqBody := map[string]any{
			"input": []any{
				map[string]any{"role": "system", "content": "First."},
				map[string]any{"role": "system", "content": "Second."},
				map[string]any{"role": "user", "content": "hi"},
			},
		}
		result := extractSystemMessagesFromInput(reqBody)
		require.True(t, result)
		require.Equal(t, "First.\n\nSecond.", reqBody["instructions"])
		input, ok := reqBody["input"].([]any)
		require.True(t, ok)
		require.Len(t, input, 1)
	})

	t.Run("mixed system and non-system preserves non-system", func(t *testing.T) {
		reqBody := map[string]any{
			"input": []any{
				map[string]any{"role": "user", "content": "hello"},
				map[string]any{"role": "system", "content": "Sys prompt."},
				map[string]any{"role": "assistant", "content": "Hi there"},
			},
		}
		result := extractSystemMessagesFromInput(reqBody)
		require.True(t, result)
		input, ok := reqBody["input"].([]any)
		require.True(t, ok)
		require.Len(t, input, 2)
		first, ok := input[0].(map[string]any)
		require.True(t, ok)
		require.Equal(t, "user", first["role"])
		second, ok := input[1].(map[string]any)
		require.True(t, ok)
		require.Equal(t, "assistant", second["role"])
	})

	t.Run("existing instructions prepended", func(t *testing.T) {
		reqBody := map[string]any{
			"input": []any{
				map[string]any{"role": "system", "content": "Extracted."},
				map[string]any{"role": "user", "content": "hi"},
			},
			"instructions": "Existing instructions.",
		}
		result := extractSystemMessagesFromInput(reqBody)
		require.True(t, result)
		require.Equal(t, "Extracted.\n\nExisting instructions.", reqBody["instructions"])
	})
}

// TestApplyCodexOAuthTransform_StripsPromptCacheRetention is a regression
// test: some clients (e.g. Cursor cloud via the Responses-shape compat path)
// send prompt_cache_retention, but the ChatGPT internal Codex endpoint
// rejects it with "Unsupported parameter: prompt_cache_retention".
func TestApplyCodexOAuthTransform_StripsPromptCacheRetention(t *testing.T) {
	reqBody := map[string]any{
		"model":                  "gpt-5.1",
		"prompt_cache_retention": "24h",
		"input": []any{
			map[string]any{"role": "user", "content": "hi"},
		},
	}

	applyCodexOAuthTransform(reqBody, false, false)

	_, stillThere := reqBody["prompt_cache_retention"]
	require.False(t, stillThere,
		"prompt_cache_retention must be stripped before forwarding to Codex upstream")
}

func TestApplyCodexOAuthTransform_ExtractsSystemMessages(t *testing.T) {
	reqBody := map[string]any{
		"model": "gpt-5.1",
		"input": []any{
			map[string]any{"role": "system", "content": "You are a coding assistant."},
			map[string]any{"role": "user", "content": "Write a function."},
		},
	}

	result := applyCodexOAuthTransform(reqBody, false, false)

	require.True(t, result.Modified)

	input, ok := reqBody["input"].([]any)
	require.True(t, ok)
	require.Len(t, input, 1)
	msg, ok := input[0].(map[string]any)
	require.True(t, ok)
	require.Equal(t, "user", msg["role"])

	instructions, ok := reqBody["instructions"].(string)
	require.True(t, ok)
	require.Equal(t, "You are a coding assistant.", instructions)
}

func TestIsInstructionsEmpty(t *testing.T) {
	tests := []struct {
		name     string
		reqBody  map[string]any
		expected bool
	}{
		{"missing field", map[string]any{}, true},
		{"nil value", map[string]any{"instructions": nil}, true},
		{"empty string", map[string]any{"instructions": ""}, true},
		{"whitespace only", map[string]any{"instructions": "   "}, true},
		{"non-string", map[string]any{"instructions": 123}, true},
		{"valid string", map[string]any{"instructions": "hello"}, false},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			result := isInstructionsEmpty(tt.reqBody)
			require.Equal(t, tt.expected, result)
		})
	}
}
