package llm

import (
	"context"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
)

func TestBuildResponsesRequest(t *testing.T) {
	req := ChatRequest{
		Model: "gpt-test",
		Messages: []Message{
			{Role: RoleSystem, Content: "be concise"},
			{Role: RoleUser, Content: "hi"},
			{
				Role:    RoleAssistant,
				Content: "let me check",
				ToolCalls: []ToolCall{{
					ID:   "call_1",
					Type: "function",
					Function: FunctionCall{
						Name:      "file_read",
						Arguments: `{"path":"README.md"}`,
					},
				}},
			},
			{Role: RoleTool, ToolCallID: "call_1", Content: "contents"},
			{Role: RoleAssistant, Content: "done"},
		},
		Tools: []Tool{{
			Type: "function",
			Function: ToolFunction{
				Name:        "file_read",
				Description: "Read a local file",
				Parameters:  json.RawMessage(`{"type":"object","properties":{}}`),
			},
		}},
		ToolChoice: "auto",
		Extra: map[string]any{
			"reasoning":   "middle",
			"thinking":    "high",
			"temperature": 0.2,
		},
	}

	payload := buildResponsesRequest(req)
	data, err := json.Marshal(payload)
	if err != nil {
		t.Fatal(err)
	}
	var raw map[string]any
	if err := json.Unmarshal(data, &raw); err != nil {
		t.Fatal(err)
	}

	if raw["model"] != "gpt-test" || raw["stream"] != true {
		t.Fatalf("model/stream = %#v / %#v", raw["model"], raw["stream"])
	}
	if raw["instructions"] != "be concise" {
		t.Fatalf("instructions = %#v", raw["instructions"])
	}
	if raw["tool_choice"] != "auto" {
		t.Fatalf("tool_choice = %#v", raw["tool_choice"])
	}

	input, ok := raw["input"].([]any)
	if !ok || len(input) != 5 {
		t.Fatalf("input = %#v", raw["input"])
	}
	checkInputItem := func(index int, wantType, wantKey, wantValue string) {
		t.Helper()
		item, ok := input[index].(map[string]any)
		if !ok {
			t.Fatalf("input[%d] = %#v", index, input[index])
		}
		if item[wantKey] != wantValue {
			t.Fatalf("input[%d].%s = %#v, want %q", index, wantKey, item[wantKey], wantValue)
		}
		if wantType != "" && item["type"] != wantType {
			t.Fatalf("input[%d].type = %#v, want %q", index, item["type"], wantType)
		}
	}
	checkInputItem(0, "", "role", "user")
	checkInputItem(1, "", "role", "assistant")
	checkInputItem(2, "function_call", "call_id", "call_1")
	checkInputItem(3, "function_call_output", "call_id", "call_1")
	checkInputItem(4, "", "role", "assistant")
	if item := input[2].(map[string]any); item["name"] != "file_read" || item["arguments"] != `{"path":"README.md"}` {
		t.Fatalf("function_call item = %#v", item)
	}
	if item := input[3].(map[string]any); item["output"] != "contents" {
		t.Fatalf("function_call_output item = %#v", item)
	}

	tools, ok := raw["tools"].([]any)
	if !ok || len(tools) != 1 {
		t.Fatalf("tools = %#v", raw["tools"])
	}
	tool := tools[0].(map[string]any)
	if tool["type"] != "function" || tool["name"] != "file_read" || tool["description"] != "Read a local file" {
		t.Fatalf("tool = %#v", tool)
	}
	if _, ok := tool["parameters"].(map[string]any); !ok {
		t.Fatalf("tool parameters = %#v", tool["parameters"])
	}

	reasoning, ok := raw["reasoning"].(map[string]any)
	if !ok || reasoning["effort"] != "medium" {
		t.Fatalf("reasoning = %#v", raw["reasoning"])
	}
	if raw["thinking"] != "high" {
		t.Fatalf("thinking = %#v", raw["thinking"])
	}
	if raw["temperature"] != 0.2 {
		t.Fatalf("temperature = %#v", raw["temperature"])
	}
}

func TestResponsesInstructionsCombinesSystemMessages(t *testing.T) {
	payload := buildResponsesRequest(ChatRequest{
		Model: "gpt-test",
		Messages: []Message{
			{Role: RoleSystem, Content: "first instruction"},
			{Role: RoleUser, Content: "hi"},
			{Role: RoleSystem, Content: "second instruction"},
		},
	})
	data, err := json.Marshal(payload)
	if err != nil {
		t.Fatal(err)
	}
	var raw map[string]any
	if err := json.Unmarshal(data, &raw); err != nil {
		t.Fatal(err)
	}
	if raw["instructions"] != "first instruction\n\nsecond instruction" {
		t.Fatalf("instructions = %#v", raw["instructions"])
	}
	input, ok := raw["input"].([]any)
	if !ok || len(input) != 1 {
		t.Fatalf("input = %#v", raw["input"])
	}
	item, ok := input[0].(map[string]any)
	if !ok || item["role"] != "user" {
		t.Fatalf("input[0] = %#v", input[0])
	}
}

func TestOpenAIResponsesClientStreamsContentAndToolCalls(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/v1/responses" {
			t.Fatalf("path = %s", r.URL.Path)
		}
		if got := r.Header.Get("Authorization"); got != "Bearer sk-test" {
			t.Fatalf("authorization = %q", got)
		}
		body := mustReadBody(t, r)
		var raw map[string]any
		if err := json.NewDecoder(strings.NewReader(body)).Decode(&raw); err != nil {
			t.Fatal(err)
		}
		if raw["stream"] != true {
			t.Fatal("request did not enable stream")
		}
		if raw["tool_choice"] != "auto" {
			t.Fatalf("tool_choice = %#v", raw["tool_choice"])
		}
		input, ok := raw["input"].([]any)
		if !ok || len(input) == 0 {
			t.Fatalf("input = %#v", raw["input"])
		}

		w.Header().Set("Content-Type", "text/event-stream")
		events := []string{
			`{"type":"response.output_item.added","output_index":0,"item":{"type":"message","id":"msg_1","role":"assistant","content":[]}}`,
			`{"type":"response.output_text.delta","item_id":"msg_1","output_index":0,"content_index":0,"delta":"Hel"}`,
			`{"type":"response.output_text.delta","item_id":"msg_1","output_index":0,"content_index":0,"delta":"lo"}`,
			`{"type":"response.output_item.added","output_index":1,"item":{"type":"function_call","id":"fc_1","call_id":"call_1","name":"file_read","arguments":""}}`,
			`{"type":"response.function_call_arguments.delta","item_id":"fc_1","output_index":1,"delta":"{\"path\""}`,
			`{"type":"response.function_call_arguments.delta","item_id":"fc_1","output_index":1,"delta":":\"README.md\"}"}`,
			`{"type":"response.function_call_arguments.done","item_id":"fc_1","output_index":1,"name":"file_read","arguments":"{\"path\":\"README.md\"}"}`,
			`{"type":"response.output_item.done","output_index":1,"item":{"type":"function_call","id":"fc_1","call_id":"call_1","name":"file_read","arguments":"{\"path\":\"README.md\"}"}}`,
			`{"type":"response.output_item.done","output_index":0,"item":{"type":"message","id":"msg_1","role":"assistant","content":[{"type":"output_text","text":"Hello"}]}}`,
			`{"type":"response.completed","response":{"id":"resp_1","status":"completed","usage":{"input_tokens":10,"output_tokens":20,"total_tokens":30}}}`,
		}
		for _, event := range events {
			_, _ = w.Write([]byte("data: " + event + "\n\n"))
		}
	}))
	defer server.Close()

	client := NewOpenAIResponsesClient(server.URL, "sk-test", server.Client())
	var content strings.Builder
	var calls []ToolCallDelta
	var finishes []string
	var usage *Usage
	err := client.ChatStream(context.Background(), ChatRequest{
		Model:      "gpt-test",
		Messages:   []Message{{Role: RoleUser, Content: "hi"}},
		ToolChoice: "auto",
		Tools: []Tool{{
			Type: "function",
			Function: ToolFunction{
				Name:        "file_read",
				Description: "Read a local file",
				Parameters:  json.RawMessage(`{"type":"object"}`),
			},
		}},
	}, func(event StreamEvent) error {
		content.WriteString(event.Content)
		calls = append(calls, event.ToolCalls...)
		if event.Usage != nil {
			usage = event.Usage
		}
		if event.FinishReason != "" {
			finishes = append(finishes, event.FinishReason)
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if content.String() != "Hello" {
		t.Fatalf("content = %q", content.String())
	}
	if len(calls) != 1 {
		t.Fatalf("calls = %#v", calls)
	}
	call := calls[0]
	if call.Index != 1 || call.ID != "call_1" || call.Name != "file_read" {
		t.Fatalf("call = %#v", call)
	}
	if call.Arguments != `{"path":"README.md"}` {
		t.Fatalf("arguments = %q", call.Arguments)
	}
	if len(finishes) != 1 || finishes[0] != "stop" {
		t.Fatalf("finishes = %#v", finishes)
	}
	if usage == nil || usage.PromptTokens != 10 || usage.CompletionTokens != 20 || usage.TotalTokens != 30 {
		t.Fatalf("usage = %#v", usage)
	}
}

func TestOpenAIResponsesClientErrorEvent(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte(`data: {"type":"error","code":"invalid_request_error","message":"bad request"}` + "\n\n"))
	}))
	defer server.Close()

	client := NewOpenAIResponsesClient(server.URL, "sk-test", server.Client())
	err := client.ChatStream(context.Background(), ChatRequest{Model: "test"}, func(StreamEvent) error {
		return nil
	})
	if err == nil || !strings.Contains(err.Error(), "bad request") {
		t.Fatalf("err = %v", err)
	}
}

func TestOpenAIResponsesClientFailedEvent(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte(`data: {"type":"response.failed","response":{"id":"resp_1","status":"failed","error":{"code":"server_error","message":"boom"}}}` + "\n\n"))
	}))
	defer server.Close()

	client := NewOpenAIResponsesClient(server.URL, "sk-test", server.Client())
	err := client.ChatStream(context.Background(), ChatRequest{Model: "test"}, func(StreamEvent) error {
		return nil
	})
	if err == nil || !strings.Contains(err.Error(), "boom") {
		t.Fatalf("err = %v", err)
	}
}

func TestOpenAIResponsesClientIncomplete(t *testing.T) {
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte(`data: {"type":"response.output_text.delta","item_id":"msg_1","output_index":0,"content_index":0,"delta":"partial"}` + "\n\n"))
		_, _ = w.Write([]byte(`data: {"type":"response.incomplete","response":{"id":"resp_1","status":"incomplete","incomplete_details":{"reason":"max_tokens"}}}` + "\n\n"))
	}))
	defer server.Close()

	client := NewOpenAIResponsesClient(server.URL, "sk-test", server.Client())
	var content strings.Builder
	var finishes []string
	err := client.ChatStream(context.Background(), ChatRequest{Model: "test"}, func(event StreamEvent) error {
		content.WriteString(event.Content)
		if event.FinishReason != "" {
			finishes = append(finishes, event.FinishReason)
		}
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if content.String() != "partial" {
		t.Fatalf("content = %q", content.String())
	}
	if len(finishes) != 1 || finishes[0] != "length" {
		t.Fatalf("finishes = %#v", finishes)
	}
}

func TestOpenAIResponsesClientRetriesTransientHTTPError(t *testing.T) {
	attempts := 0
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		attempts++
		if attempts == 1 {
			http.Error(w, "temporary", http.StatusBadGateway)
			return
		}
		w.Header().Set("Content-Type", "text/event-stream")
		_, _ = w.Write([]byte(`data: {"type":"response.output_text.delta","item_id":"msg_1","output_index":0,"content_index":0,"delta":"ok"}` + "\n\n"))
		_, _ = w.Write([]byte(`data: {"type":"response.completed","response":{"id":"resp_1","status":"completed"}}` + "\n\n"))
	}))
	defer server.Close()

	client := NewOpenAIResponsesClient(server.URL, "sk-test", server.Client())
	var content strings.Builder
	err := client.ChatStream(context.Background(), ChatRequest{Model: "test"}, func(event StreamEvent) error {
		content.WriteString(event.Content)
		return nil
	})
	if err != nil {
		t.Fatal(err)
	}
	if attempts != 2 {
		t.Fatalf("attempts = %d, want 2", attempts)
	}
	if content.String() != "ok" {
		t.Fatalf("content = %q", content.String())
	}
}