package promptkit_test

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"reflect"
	"testing"

	"go.maximumdirect.net/promptkit"
)

type receiverMutatingProviderMap map[string]string

func (value receiverMutatingProviderMap) MarshalJSON() ([]byte, error) {
	value["value"] = "encoded"
	if value["fail"] == "yes" {
		return nil, errors.New("synthetic encoding failure")
	}
	return json.Marshal(map[string]string(value))
}

func TestBuiltInEncodingPreservesPreparedProviderValues(t *testing.T) {
	for _, fail := range []bool{false, true} {
		name := "successful encoding"
		if fail {
			name = "encoding failure diagnostics"
		}
		t.Run(name, func(t *testing.T) {
			calls := 0
			config := simpleConfig("message")
			config.HTTPClient = &http.Client{Transport: encodingOwnershipTransport(t, &calls)}
			engine, err := promptkit.NewEngine(config)
			if err != nil {
				t.Fatal(err)
			}
			options := receiverMutatingProviderMap{"value": "original"}
			if fail {
				options["fail"] = "yes"
			}
			prepared, err := engine.PrepareExecution(context.Background(), promptkit.RunRequest{
				PromptID: "prompt", Execution: &promptkit.ExecutionTargetOverride{
					ExtraParams: map[string]any{"options": options},
				},
			})
			if err != nil {
				t.Fatal(err)
			}
			before := prepared.Details()
			result, err := engine.RunPrepared(context.Background(), prepared)
			if fail {
				if !errors.Is(err, promptkit.ErrInvalidRequest) || result != nil || calls != 0 {
					t.Fatalf("encoding failure: result=%+v error=%v dispatches=%d", result, err, calls)
				}
			} else if err != nil || result == nil || calls != 1 {
				t.Fatalf("successful encoding: result=%+v error=%v dispatches=%d", result, err, calls)
			} else if result.EffectiveModelParams.ExtraParams["options"].(receiverMutatingProviderMap)["value"] != "original" {
				t.Fatal("custom encoder changed result settings")
			}
			if !reflect.DeepEqual(before, prepared.Details()) {
				t.Fatal("custom encoder changed retained prepared details")
			}
			if options["value"] != "original" {
				t.Fatal("custom encoder changed caller input")
			}
		})
	}
}

func TestBuiltInEncodingPreservesSmokeProviderValues(t *testing.T) {
	calls := 0
	config := simpleConfig("unused")
	config.HTTPClient = &http.Client{Transport: encodingOwnershipTransport(t, &calls)}
	engine, err := promptkit.NewEngine(config)
	if err != nil {
		t.Fatal(err)
	}
	options := receiverMutatingProviderMap{"value": "original"}
	report, err := engine.SmokeTest(context.Background(), promptkit.SmokeTestRequest{
		Kind: promptkit.SmokeTestTextInference, ProfileID: "profile",
		Execution: &promptkit.ExecutionTargetOverride{ExtraParams: map[string]any{"options": options}},
	})
	if err != nil || report == nil || !report.Completed || calls != 1 {
		t.Fatalf("smoke result=%+v error=%v dispatches=%d", report, err, calls)
	}
	if report.Target.EffectiveSettings.ExtraParams["options"].(receiverMutatingProviderMap)["value"] != "original" {
		t.Fatal("custom encoder changed smoke report settings")
	}
	if options["value"] != "original" {
		t.Fatal("custom encoder changed caller input")
	}
}

func encodingOwnershipTransport(t *testing.T, calls *int) roundTripFunc {
	t.Helper()
	return func(request *http.Request) (*http.Response, error) {
		*calls += 1
		var payload struct {
			Options map[string]string `json:"options"`
		}
		if err := json.NewDecoder(request.Body).Decode(&payload); err != nil {
			return nil, err
		}
		if payload.Options["value"] != "encoded" {
			t.Errorf("custom wire encoding was lost: options=%v", payload.Options)
		}
		return observedHTTPResponse(http.StatusOK, `{"choices":[{"message":{"content":"PROMPTKIT_OK"}}]}`), nil
	}
}