package api

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

	"github.com/gin-gonic/gin"

	"github.com/dhao2001/mygo/internal/model"
)

func TestError(t *testing.T) {
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/error", func(c *gin.Context) {
		Error(c, http.StatusBadRequest, "invalid request")
	})

	req := httptest.NewRequest(http.MethodGet, "/error", nil)
	rec := httptest.NewRecorder()

	router.ServeHTTP(rec, req)

	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}

	var body ErrorResponse
	if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
		t.Fatalf("unmarshal response: %v", err)
	}

	if body.Error.Message != "invalid request" {
		t.Errorf("message = %q, want %q", body.Error.Message, "invalid request")
	}
	if body.Error.LogID != "" {
		t.Errorf("log_id = %q, want empty", body.Error.LogID)
	}
}

func TestRespondErrorMapsDomainKinds(t *testing.T) {
	tests := []struct {
		name       string
		err        error
		wantStatus int
		wantLogID  bool
	}{
		{"invalid argument", model.NewInvalidArgumentError("bad input"), http.StatusBadRequest, false},
		{"unauthenticated", model.NewUnauthenticatedError("invalid token"), http.StatusUnauthorized, false},
		{"permission denied", model.NewPermissionDeniedError("access denied", nil), http.StatusForbidden, false},
		{"not found", model.NewNotFoundError("missing", nil), http.StatusNotFound, false},
		{"conflict", model.NewConflictError("duplicate"), http.StatusConflict, false},
		{"payload too large", model.NewPayloadTooLargeError("too large", nil), http.StatusRequestEntityTooLarge, false},
		{"internal", model.NewInternalError("lookup", errors.New("database offline")), http.StatusInternalServerError, true},
		{"unknown", errors.New("escaped error"), http.StatusInternalServerError, true},
		{"permission denied sentinel cause", model.NewPermissionDeniedError("access denied", model.ErrForbidden), http.StatusForbidden, false},
		{"not found sentinel cause", model.NewNotFoundError("missing", model.ErrNotFound), http.StatusNotFound, false},
		{"payload too large sentinel cause", model.NewPayloadTooLargeError("too large", model.ErrUploadTooLarge), http.StatusRequestEntityTooLarge, false},
		{"client with diagnostic cause", model.NewPermissionDeniedError("access denied", errors.New("policy backend failed")), http.StatusForbidden, true},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			rec := exerciseRespondError(tt.err)
			if rec.Code != tt.wantStatus {
				t.Fatalf("status = %d, want %d; body = %s", rec.Code, tt.wantStatus, rec.Body.String())
			}

			var body ErrorResponse
			if err := json.Unmarshal(rec.Body.Bytes(), &body); err != nil {
				t.Fatalf("unmarshal response: %v", err)
			}

			if tt.wantLogID && body.Error.LogID == "" {
				t.Fatalf("log_id is empty, want populated; body = %s", rec.Body.String())
			}
			if !tt.wantLogID && body.Error.LogID != "" {
				t.Fatalf("log_id = %q, want empty", body.Error.LogID)
			}
			if rec.Code >= http.StatusInternalServerError && body.Error.Message != "internal server error" {
				t.Fatalf("message = %q, want sanitized internal message", body.Error.Message)
			}
		})
	}
}

func exerciseRespondError(err error) *httptest.ResponseRecorder {
	gin.SetMode(gin.TestMode)
	router := gin.New()
	router.GET("/error", func(c *gin.Context) {
		RespondError(c, err)
	})

	req := httptest.NewRequest(http.MethodGet, "/error", nil)
	rec := httptest.NewRecorder()
	router.ServeHTTP(rec, req)
	return rec
}