package retry

import (
	"net/http"
	"testing"
	"time"
)

func TestCompositeRetryPolicy_FirstDecisionWins(t *testing.T) {
	p := NewCompositeRetryPolicy(
		&stubPolicy{decision: nil}, // 不表态
		&stubPolicy{decision: &RetryDecision{Retry: true, Reason: "second wins"}},
		&stubPolicy{decision: &RetryDecision{Retry: false, Reason: "third"}},
	)

	d := p.ShouldRetry(makeErr("server_overload"), 1, defaultCtx())
	if d == nil || !d.Retry || d.Reason != "second wins" {
		t.Errorf("expected second policy to win, got %+v", d)
	}
}

func TestCompositeRetryPolicy_NoPolicyMatched(t *testing.T) {
	p := NewCompositeRetryPolicy(
		&stubPolicy{decision: nil},
		&stubPolicy{decision: nil},
	)

	d := p.ShouldRetry(makeErr("unknown"), 1, defaultCtx())
	if d == nil || d.Retry {
		t.Error("expected no-retry when no policy matched")
	}
}

func TestCompositeRetryPolicy_Add(t *testing.T) {
	p := NewCompositeRetryPolicy()
	p.Add(&stubPolicy{decision: &RetryDecision{Retry: true, Reason: "added"}})

	d := p.ShouldRetry(makeErr("api_timeout"), 1, defaultCtx())
	if d == nil || !d.Retry {
		t.Error("added policy should work")
	}
}

// ============================================================
// 辅助
// ============================================================

type stubPolicy struct {
	decision *RetryDecision
}

func (s *stubPolicy) ShouldRetry(err RetryError, attempt int, ctx *RetryContext) *RetryDecision {
	return s.decision
}

// mockRetryError 是 RetryError 的测试用实现,避免 retry 包测试 import api 包(循环依赖).
// 精妙之处(CLEVER): retry 包通过 RetryError 接口与 api 包解耦,
// 测试用 mock 替代真实 APIError,circular import 问题彻底消失.
type mockRetryError struct {
	category  string
	retryable bool
	delay     time.Duration
	headers   http.Header
	retryInfo *RetryInfo
}

func (m *mockRetryError) Error() string     { return "mock: " + m.category }
func (m *mockRetryError) Category() string  { return m.category }
func (m *mockRetryError) IsRetryable() bool { return m.retryable }
func (m *mockRetryError) RetryDelay() time.Duration {
	if m.retryInfo != nil {
		return m.retryInfo.After
	}
	return m.delay
}
func (m *mockRetryError) Message() string       { return m.category }
func (m *mockRetryError) Headers() http.Header  { return m.headers }
func (m *mockRetryError) RetryInfo() *RetryInfo { return m.retryInfo }

// makeErr 创建给定类别的可重试 mock 错误.
func makeErr(category string) *mockRetryError {
	retryable := false
	switch category {
	case "api_timeout", "server_overload", "server_error", "connection_error":
		retryable = true
	}
	return &mockRetryError{
		category:  category,
		retryable: retryable,
		retryInfo: &RetryInfo{Retryable: retryable},
	}
}

func defaultCtx() *RetryContext {
	return &RetryContext{
		IsForeground:      true,
		StartTime:         time.Now(),
		ConsecutiveCounts: make(map[string]int),
	}
}