package errors

import (
	"errors"
	"testing"
)

func TestNew(t *testing.T) {
	e := New(CategoryInternal, "something went wrong")

	if e.Category != CategoryInternal {
		t.Errorf("Expected category Internal, got %v", e.Category)
	}
	if e.Message != "something went wrong" {
		t.Errorf("Expected message 'something went wrong', got '%s'", e.Message)
	}
	if e.StatusCode != 500 {
		t.Errorf("Expected status code 500, got %d", e.StatusCode)
	}
	if e.Retryable {
		t.Error("Internal errors should not be retryable by default")
	}
}

func TestNewWithCause(t *testing.T) {
	cause := errors.New("underlying error")
	e := NewWithCause(CategoryUpstream, "upstream failed", cause)

	if e.Cause != cause {
		t.Error("Cause not set correctly")
	}

	expectedMsg := "[upstream] upstream failed: underlying error"
	if e.Error() != expectedMsg {
		t.Errorf("Expected error message '%s', got '%s'", expectedMsg, e.Error())
	}
}

func TestWrap(t *testing.T) {
	original := errors.New("original error")
	wrapped := Wrap(original, CategoryNetwork, "network issue")

	if wrapped == nil {
		t.Fatal("Wrap returned nil for non-nil error")
	}

	if wrapped.Cause != original {
		t.Error("Wrapped error should preserve original cause")
	}

	pe := New(CategoryRateLimit, "rate limited")
	wrapped2 := Wrap(pe, CategoryUnknown, "wrapped")

	if wrapped2 != pe {
		t.Error("Wrapping PipelineError should return the same error")
	}
}

func TestWrapNil(t *testing.T) {
	wrapped := Wrap(nil, CategoryInternal, "test")
	if wrapped != nil {
		t.Error("Wrapping nil should return nil")
	}
}

func TestErrorHelpers(t *testing.T) {
	tests := []struct {
		name           string
		err            *PipelineError
		expectedCat    ErrorCategory
		expectedStatus int
		expectedRetry  bool
	}{
		{"Auth", AuthError("unauthorized"), CategoryAuth, 401, false},
		{"RateLimit", RateLimitError("too many requests"), CategoryRateLimit, 429, true},
		{"Validation", ValidationError("invalid input"), CategoryValidation, 400, false},
		{"Upstream", UpstreamError("provider down"), CategoryUpstream, 502, true},
		{"Internal", InternalError("server error"), CategoryInternal, 500, false},
		{"Network", NetworkError("connection lost"), CategoryNetwork, 503, true},
		{"Timeout", TimeoutError("request timeout"), CategoryTimeout, 504, true},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			if tt.err.Category != tt.expectedCat {
				t.Errorf("Expected category %v, got %v", tt.expectedCat, tt.err.Category)
			}
			if tt.err.StatusCode != tt.expectedStatus {
				t.Errorf("Expected status %d, got %d", tt.expectedStatus, tt.err.StatusCode)
			}
			if tt.err.Retryable != tt.expectedRetry {
				t.Errorf("Expected retryable=%v, got %v", tt.expectedRetry, tt.err.Retryable)
			}
		})
	}
}

func TestWithContext(t *testing.T) {
	e := New(CategoryValidation, "invalid field").
		WithContext("field", "email").
		WithContext("value", "invalid-email")

	if e.Context == nil {
		t.Fatal("Context should not be nil")
	}

	if e.Context["field"] != "email" {
		t.Errorf("Expected field='email', got %v", e.Context["field"])
	}
}

func TestIsPipelineError(t *testing.T) {
	pe := New(CategoryInternal, "test")
	result, ok := IsPipelineError(pe)
	if !ok {
		t.Error("IsPipelineError should return true for PipelineError")
	}
	if result != pe {
		t.Error("IsPipelineError should return the same error")
	}

	stdErr := errors.New("standard error")
	_, ok = IsPipelineError(stdErr)
	if ok {
		t.Error("IsPipelineError should return false for standard error")
	}
}

func TestIsRetryableError(t *testing.T) {
	rateLimit := RateLimitError("test")
	if !IsRetryableError(rateLimit) {
		t.Error("Rate limit error should be retryable")
	}

	auth := AuthError("test")
	if IsRetryableError(auth) {
		t.Error("Auth error should not be retryable")
	}
}