package llm

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

// TestRetryOn500：前两次 500，第三次成功——provider 应自动重试。
func TestRetryOn500(t *testing.T) {
	calls := 0
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calls++
		if calls <= 2 {
			w.WriteHeader(http.StatusInternalServerError)
			return
		}
		w.Header().Set("Content-Type", "text/event-stream")
		w.Write([]byte("data: {\"choices\":[{\"delta\":{\"content\":\"ok\"}}]}\n\n"))
		w.Write([]byte("data: [DONE]\n\n"))
	}))
	defer srv.Close()

	p := &OpenAIProvider{BaseURL: srv.URL, APIKey: "k", Model: "m", HTTP: srv.Client()}
	final, err := p.Stream(context.Background(), "sys", []Message{{Role: RoleUser, Content: "hi"}}, nil, StreamOptions{}, nil)
	if err != nil {
		t.Fatalf("stream should succeed after retries: %v", err)
	}
	if final.Content != "ok" || calls != 3 {
		t.Fatalf("content=%q calls=%d", final.Content, calls)
	}
}

// TestNoRetryOn400：4xx 属不可重试错误，应立即返回。
func TestNoRetryOn400(t *testing.T) {
	calls := 0
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		calls++
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte(`{"error":"bad request"}`))
	}))
	defer srv.Close()

	p := &OpenAIProvider{BaseURL: srv.URL, APIKey: "k", Model: "m", HTTP: srv.Client()}
	_, err := p.Stream(context.Background(), "sys", nil, nil, StreamOptions{}, nil)
	if err == nil || !strings.Contains(err.Error(), "400") {
		t.Fatalf("expected 400 error, got %v", err)
	}
	if calls != 1 {
		t.Fatalf("4xx must not retry, calls=%d", calls)
	}
}

// TestAnthropicCacheControlAndMaxTokens：system/tools 标记 cache_control，
// max_tokens 来自 provider 配置。
func TestAnthropicCacheControlAndMaxTokens(t *testing.T) {
	var body map[string]any
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_ = json.NewDecoder(r.Body).Decode(&body)
		w.Header().Set("Content-Type", "text/event-stream")
		// 带一句正文：只发 message_stop 的空流现在会被当成失败（见 ErrEmptyCompletion），
		// 而这条用例断言的是**请求体**形状。
		w.Write([]byte("data: {\"type\":\"content_block_delta\",\"index\":0,\"delta\":{\"type\":\"text_delta\",\"text\":\"ok\"}}\n\n"))
		w.Write([]byte("data: {\"type\":\"message_stop\"}\n\n"))
	}))
	defer srv.Close()

	p := &AnthropicProvider{BaseURL: srv.URL, APIKey: "k", Model: "m", MaxTokens: 4096, HTTP: srv.Client()}
	_, err := p.Stream(context.Background(), "system prompt",
		[]Message{{Role: RoleUser, Content: "hi"}},
		[]ToolDef{{Name: "read", Description: "d", Parameters: map[string]any{"type": "object"}}}, StreamOptions{}, nil)
	if err != nil {
		t.Fatal(err)
	}
	if body["max_tokens"].(float64) != 4096 {
		t.Fatalf("max_tokens: %v", body["max_tokens"])
	}
	sys := body["system"].([]any)
	s0 := sys[0].(map[string]any)
	if s0["cache_control"].(map[string]any)["type"] != "ephemeral" {
		t.Fatalf("system cache_control missing: %v", s0)
	}
	tools := body["tools"].([]any)
	last := tools[len(tools)-1].(map[string]any)
	if last["cache_control"].(map[string]any)["type"] != "ephemeral" {
		t.Fatalf("tools cache_control missing: %v", last)
	}
}

func TestParseRetryAfter(t *testing.T) {
	if got := parseRetryAfter("3"); got != 3*time.Second {
		t.Fatalf("got %v", got)
	}
	if got := parseRetryAfter(""); got != 0 {
		t.Fatalf("got %v", got)
	}
	if got := parseRetryAfter("99999"); got != 0 { // 上限保护
		t.Fatalf("got %v", got)
	}
}