package vision

import (
	"context"
	"encoding/base64"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"
)

// TestEmbedReturnsVectorsAndSkipsBroken 验证正常路径：批量编码返回向量，
// 服务端跳过的图片下标原样带回，向量维度与配置一致。
func TestEmbedReturnsVectorsAndSkipsBroken(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/embed" {
			t.Errorf("路径不对: %s", r.URL.Path)
		}
		_ = json.NewEncoder(w).Encode(map[string]any{
			"dim":     768,
			"vectors": [][]float32{make([]float32, 768), make([]float32, 768)},
			"indexes": []int{0, 2},
			"skipped": []int{1},
			"device":  "cpu",
		})
	}))
	defer srv.Close()

	c := New(srv.URL, 768, 2*time.Second, 3)
	vecs, skipped, err := c.Embed(context.Background(), [][]byte{[]byte("a"), []byte("b"), []byte("c")})
	if err != nil {
		t.Fatalf("Embed 返回错误: %v", err)
	}
	if len(vecs) != 2 {
		t.Fatalf("应有 2 个向量，得到 %d", len(vecs))
	}
	if len(skipped) != 1 || skipped[0] != 1 {
		t.Fatalf("skipped 应为 [1]，得到 %v", skipped)
	}
	if len(vecs[0]) != 768 {
		t.Fatalf("向量维度应为 768，得到 %d", len(vecs[0]))
	}
}

// TestEmbedDisabledSkipsCall 验证禁用后完全不发起 HTTP 请求（视觉服务未启用时的零开销路径）。
func TestEmbedDisabledSkipsCall(t *testing.T) {
	called := false
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		called = true
	}))
	defer srv.Close()

	c := New(srv.URL, 768, time.Second, 3)
	c.Disable()
	vecs, skipped, err := c.Embed(context.Background(), [][]byte{[]byte("x")})
	if err != ErrUnavailable {
		t.Fatalf("禁用时应返回 ErrUnavailable，实际 %v", err)
	}
	if vecs != nil || skipped != nil {
		t.Fatalf("禁用时应返回 nil，实际 %v %v", vecs, skipped)
	}
	if called {
		t.Fatal("禁用时不应发起 HTTP 请求")
	}
}

// TestEmbedDimensionMismatchIsError 验证维度不符必须报错：
// 若放过，会把错误维度的向量写进 image_embeddings 造成脏数据。
func TestEmbedDimensionMismatchIsError(t *testing.T) {
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_ = json.NewEncoder(w).Encode(map[string]any{
			"dim": 512, "vectors": [][]float32{make([]float32, 512)}, "indexes": []int{0}, "skipped": []int{},
		})
	}))
	defer srv.Close()

	c := New(srv.URL, 768, time.Second, 3)
	if _, _, err := c.Embed(context.Background(), [][]byte{[]byte("x")}); err == nil {
		t.Fatal("维度不符应返回错误")
	}
}

// TestEmbedTripBreakerThenCooldownSkips 验证熔断：连续失败达阈值后进入冷却，
// 冷却期内直接返回错误且不再发起请求（避免每张图都卡在超时上）。
func TestEmbedTripBreakerThenCooldownSkips(t *testing.T) {
	hits := 0
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		hits++
		w.WriteHeader(http.StatusInternalServerError)
	}))
	defer srv.Close()

	c := New(srv.URL, 768, time.Second, 3)
	for i := 0; i < 3; i++ {
		if _, _, err := c.Embed(context.Background(), [][]byte{[]byte("x")}); err == nil {
			t.Fatalf("第 %d 次调用应报错", i+1)
		}
	}
	if c.Open() {
		t.Fatal("熔断后 Open 应为 false")
	}
	before := hits
	if _, _, err := c.Embed(context.Background(), [][]byte{[]byte("x")}); err == nil {
		t.Fatalf("熔断期应直接返回错误: %v", err)
	}
	if hits != before {
		t.Fatalf("熔断期间不应再发起请求，hits 从 %d 变为 %d", before, hits)
	}
}

// TestEmbedSendsBase64Payload 验证请求体格式（base64 编码的图片数组），
// 这是与服务端约定的契约，写错会导致服务端解码失败。
func TestEmbedSendsBase64Payload(t *testing.T) {
	var got struct {
		Images []string `json:"images"`
	}
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		_ = json.NewDecoder(r.Body).Decode(&got)
		_ = json.NewEncoder(w).Encode(map[string]any{
			"dim": 768, "vectors": [][]float32{make([]float32, 768)}, "indexes": []int{0}, "skipped": []int{},
		})
	}))
	defer srv.Close()

	c := New(srv.URL, 768, time.Second, 3)
	if _, _, err := c.Embed(context.Background(), [][]byte{[]byte("hello")}); err != nil {
		t.Fatalf("Embed 返回错误: %v", err)
	}
	want := base64.StdEncoding.EncodeToString([]byte("hello"))
	if len(got.Images) != 1 || got.Images[0] != want {
		t.Fatalf("请求体 base64 不正确: %v", got.Images)
	}
}

// TestEmbedEmptyInputIsNoop 验证空输入不发起请求、不报错。
func TestEmbedEmptyInputIsNoop(t *testing.T) {
	called := false
	srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		called = true
	}))
	defer srv.Close()

	c := New(srv.URL, 768, time.Second, 3)
	vecs, skipped, err := c.Embed(context.Background(), nil)
	if err != nil || vecs != nil || skipped != nil {
		t.Fatalf("空输入应返回 nil,nil,nil，实际 %v %v %v", vecs, skipped, err)
	}
	if called {
		t.Fatal("空输入不应发起请求")
	}
}

// TestEmbedBatchTooLarge 验证单批上限，超限直接拒绝（避免把一张大图撑爆服务端）。
func TestEmbedBatchTooLarge(t *testing.T) {
	c := New("http://127.0.0.1:1", 768, time.Second, 3)
	imgs := make([][]byte, MaxBatch+1)
	for i := range imgs {
		imgs[i] = []byte("x")
	}
	if _, _, err := c.Embed(context.Background(), imgs); err != ErrBatchTooLarge {
		t.Fatalf("超上限应返回 ErrBatchTooLarge，实际 %v", err)
	}
}