package openai

import (
	"context"
	"fmt"
	"net/http"
	"sync"

	edgeservice "iop/apps/edge/internal/service"
	iop "iop/proto/gen/iop"
)

// newTestChatDispatchContext builds the minimal dispatch context a chat
// completion stage needs when a test drives that stage directly instead of
// going through the ingress handler.
func newTestChatDispatchContext(r *http.Request, req chatCompletionRequest) *chatDispatchContext {
	return &chatDispatchContext{
		openAIRequestContext: openAIRequestContext{
			r:        r,
			endpoint: usageEndpointChatCompletions,
		},
		req: req,
		retrySubmit: func(ctx context.Context, retryReq edgeservice.SubmitRunRequest) (any, error) {
			return nil, nil
		},
	}
}

// fakeRunService is the small default double for the normalized run, cancel,
// and Ollama surfaces. Provider tunnel/pool scenarios use
// providerFakeRunService, which embeds this type.
type fakeRunService struct {
	req        edgeservice.SubmitRunRequest
	reqs       []edgeservice.SubmitRunRequest
	ollamaReq  edgeservice.OllamaAPIRequest
	ollamaResp edgeservice.OllamaAPIView
	events     chan *iop.RunEvent
	eventRuns  []chan *iop.RunEvent
	runIDs     []string

	submitMu       sync.Mutex
	submitErrAfter int // zero means no error; >=1 means error starts from this req index (1-based)
	cancelMu       sync.Mutex
	cancelCalls    []edgeservice.CancelRunRequest
}

// SubmitProviderTunnel fails fast: a fixture reaching the provider tunnel path
// must use providerFakeRunService.
func (s *fakeRunService) SubmitProviderTunnel(context.Context, edgeservice.SubmitProviderTunnelRequest) (edgeservice.ProviderTunnelResult, error) {
	return nil, fmt.Errorf("fakeRunService: provider tunnel dispatch is not configured; use providerFakeRunService")
}

// SubmitProviderPool fails fast: a fixture reaching the provider-pool path must
// use providerFakeRunService.
func (s *fakeRunService) SubmitProviderPool(context.Context, edgeservice.ProviderPoolDispatchRequest) (*edgeservice.ProviderPoolDispatchResult, error) {
	return nil, fmt.Errorf("fakeRunService: provider pool dispatch is not configured; use providerFakeRunService")
}

func (s *fakeRunService) reqsSnapshot() []edgeservice.SubmitRunRequest {
	s.submitMu.Lock()
	defer s.submitMu.Unlock()
	return append([]edgeservice.SubmitRunRequest(nil), s.reqs...)
}

func (s *fakeRunService) CancelRun(_ context.Context, req edgeservice.CancelRunRequest) (edgeservice.CommandResult, error) {
	s.cancelMu.Lock()
	s.cancelCalls = append(s.cancelCalls, req)
	s.cancelMu.Unlock()
	return edgeservice.CommandResult{NodeID: req.NodeRef, SessionID: req.SessionID}, nil
}

func (s *fakeRunService) cancelCallsSnapshot() []edgeservice.CancelRunRequest {
	s.cancelMu.Lock()
	defer s.cancelMu.Unlock()
	return append([]edgeservice.CancelRunRequest(nil), s.cancelCalls...)
}

func (s *fakeRunService) SubmitRun(_ context.Context, req edgeservice.SubmitRunRequest) (edgeservice.RunResult, error) {
	s.submitMu.Lock()
	s.req = req
	s.reqs = append(s.reqs, req)
	attempt := len(s.reqs)
	if s.submitErrAfter > 0 && attempt >= s.submitErrAfter {
		s.submitMu.Unlock()
		return nil, fmt.Errorf("inject error after %d attempts", attempt-1)
	}
	events := s.events
	if attempt-1 < len(s.eventRuns) {
		events = s.eventRuns[attempt-1]
	}
	runID := "run-test"
	if attempt-1 < len(s.runIDs) {
		runID = s.runIDs[attempt-1]
	} else if attempt > 1 {
		runID = fmt.Sprintf("run-test-%d", attempt)
	}
	s.submitMu.Unlock()
	return &edgeservice.RunHandle{
		RunDispatch: edgeservice.RunDispatch{
			RunID:         runID,
			ModelGroupKey: req.ModelGroupKey,
			Adapter:       req.Adapter,
			Target:        req.Target,
			SessionID:     req.SessionID,
			TimeoutSec:    5,
		},
		RunStream: edgeservice.RunStream{
			Events:     events,
			NodeEvents: make(chan *iop.EdgeNodeEvent),
		},
	}, nil
}

func (s *fakeRunService) OllamaAPI(_ context.Context, req edgeservice.OllamaAPIRequest) (edgeservice.OllamaAPIView, error) {
	s.ollamaReq = req
	if s.ollamaResp.StatusCode == 0 {
		s.ollamaResp.StatusCode = http.StatusOK
	}
	return s.ollamaResp, nil
}

func bufferedRunEvents(events ...*iop.RunEvent) chan *iop.RunEvent {
	ch := make(chan *iop.RunEvent, len(events))
	for _, event := range events {
		ch <- event
	}
	return ch
}