package gateway

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

	"git.yeij.top/AskaEth/Cyrene_v2/internal/auth"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/runtime/history"
)

// 本文件覆盖 PATCH /api/v1/sessions/{id} 的两个 400 文案之别：
// 「字段缺失」（title 与 pinned 都没给）与「字段在、值非法」
// （title 存在但 trim 后为空白）必须给出不同的说明——否则
// 空白标题读起来像「缺字段」，客户端会去补一个本就在的键。
// 同时钉住客户端依赖的既有语义：空串/仅空白**不能**清空标题
// （因此客户端不提供「恢复自动命名」入口）。

// patchSessionError 解出 PATCH /sessions/{id} 失败响应的
// {code,message}，使断言针对客户端看到的文案本身。
func patchSessionError(t *testing.T, body []byte) (string, string) {
	t.Helper()
	var eobj struct {
		Code    string `json:"code"`
		Message string `json:"message"`
	}
	if err := json.Unmarshal(decodeBody(t, body)["error"], &eobj); err != nil {
		t.Fatalf("decode error envelope: %v (body=%s)", err, body)
	}
	return eobj.Code, eobj.Message
}

// sessionTitle 读回列表里某会话的标题，用于断言标题未被改写。
func sessionTitle(t *testing.T, ts *httptest.Server, tok, id string) string {
	t.Helper()
	resp, body := doReq(t, http.MethodGet, ts.URL+"/api/v1/sessions", nil, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("list sessions status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	var sessions []struct {
		ID    string `json:"id"`
		Title string `json:"title"`
	}
	decodeDataSlice(t, body, &sessions)
	for _, s := range sessions {
		if s.ID == id {
			return s.Title
		}
	}
	t.Fatalf("session %s missing from list", id)
	return ""
}

// TestPatchSessionDistinguishesMissingFromBlank 断言两类 400 的文案互不相同
// 且各自说到点上：都缺字段时说明「至少需要 title 或 pinned」，
// 只有 title 且为空白时说明「title 不得为空白」（不是
// 读起来像缺字段的 "title is required"）。
func TestPatchSessionDistinguishesMissingFromBlank(t *testing.T) {
	t.Parallel()
	_, ts, jwt, _ := newHistoryEnv(t)
	tok := signAny(t, jwt, "acct", auth.RoleOwner)
	base := ts.URL + "/api/v1/sessions/" + history.MainSessionID

	// ① 两个字段都没给：文案必须点名两个可给的字段。
	resp, body := doReq(t, http.MethodPatch, base, map[string]any{}, tok)
	if resp.StatusCode != http.StatusBadRequest {
		t.Fatalf("empty body status = %d, want 400 (body=%s)", resp.StatusCode, body)
	}
	code, missingMsg := patchSessionError(t, body)
	if code != "bad_request" {
		t.Fatalf("empty body code = %q, want bad_request (body=%s)", code, body)
	}
	if !strings.Contains(missingMsg, "title") || !strings.Contains(missingMsg, "pinned") {
		t.Fatalf("empty body message = %q, want it to name both title and pinned", missingMsg)
	}
	t.Logf("字段缺失 → %s", body)

	// ② title 在但为空白：文案必须说「不得为空白」，且与 ① 不同。
	for _, blank := range []string{"", "   ", " \t\n "} {
		resp, body = doReq(t, http.MethodPatch, base, map[string]any{"title": blank}, tok)
		if resp.StatusCode != http.StatusBadRequest {
			t.Fatalf("blank title %q status = %d, want 400 (body=%s)", blank, resp.StatusCode, body)
		}
		code, blankMsg := patchSessionError(t, body)
		if code != "bad_request" {
			t.Fatalf("blank title %q code = %q, want bad_request (body=%s)", blank, code, body)
		}
		if blankMsg != "title must not be blank" {
			t.Fatalf("blank title %q message = %q, want %q", blank, blankMsg, "title must not be blank")
		}
		if blankMsg == missingMsg {
			t.Fatalf("blank and missing share message %q, want the two cases distinguishable", blankMsg)
		}
		if strings.Contains(blankMsg, "is required") {
			t.Fatalf("blank title message = %q, want it not to read as a missing field", blankMsg)
		}
		t.Logf("字段在但空白 → %s", body)
	}

	// ③ 既存语义不变：空白 PATCH 不改标题（标题无法清空）。
	resp, body = doReq(t, http.MethodPatch, base, map[string]any{"title": "  保留我  "}, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("rename status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
	if got := sessionTitle(t, ts, tok, history.MainSessionID); got != "保留我" {
		t.Fatalf("title after rename = %q, want 保留我", got)
	}
	resp, body = doReq(t, http.MethodPatch, base, map[string]any{"title": ""}, tok)
	if resp.StatusCode != http.StatusBadRequest {
		t.Fatalf("clear attempt status = %d, want 400 (body=%s)", resp.StatusCode, body)
	}
	if got := sessionTitle(t, ts, tok, history.MainSessionID); got != "保留我" {
		t.Fatalf("title after clear attempt = %q, want it unchanged at 保留我", got)
	}

	// ④ 只给 pinned（无 title）仍然可用：区分文案不得收紧原有契约。
	resp, body = doReq(t, http.MethodPatch, base, map[string]any{"pinned": true}, tok)
	if resp.StatusCode != http.StatusOK {
		t.Fatalf("pin-only status = %d, want 200 (body=%s)", resp.StatusCode, body)
	}
}