package executor

import (
	"bufio"
	"bytes"
	"context"
	"errors"
	"fmt"
	"io"
	"net/http"
	"time"

	"github.com/router-for-me/CLIProxyAPI/v7/internal/runtime/executor/helps"
	"github.com/router-for-me/CLIProxyAPI/v7/internal/thinking"
	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v7/sdk/cliproxy/auth"
	cliproxyexecutor "github.com/router-for-me/CLIProxyAPI/v7/sdk/cliproxy/executor"
	sdktranslator "github.com/router-for-me/CLIProxyAPI/v7/sdk/translator"
	log "github.com/sirupsen/logrus"
	"github.com/tidwall/sjson"
)

// ExecuteStream performs a streaming request to the Antigravity API.
func (e *AntigravityExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (_ *cliproxyexecutor.StreamResult, err error) {
	if opts.Alt == "responses/compact" {
		return nil, statusErr{code: http.StatusNotImplemented, msg: "/responses/compact not supported"}
	}
	baseModel := thinking.ParseSuffix(req.Model).ModelName

	ctx = context.WithValue(ctx, "alt", "")
	if inCooldown, remaining, errCooldown := antigravityIsInShortCooldownRequired(ctx, auth, baseModel, time.Now()); errCooldown != nil {
		return nil, homeKVUnavailableStatusErr(errCooldown)
	} else if inCooldown && !antigravityShouldBypassShortCooldown(ctx, e.cfg) {
		log.Debugf("antigravity executor: auth %s in short cooldown for model %s (%s remaining), returning 429 to switch auth", auth.ID, baseModel, remaining)
		d := remaining
		return nil, statusErr{code: http.StatusTooManyRequests, msg: fmt.Sprintf("auth in short cooldown, %s remaining", remaining), retryAfter: &d}
	}

	reporter := helps.NewExecutorUsageReporter(ctx, e, baseModel, auth)
	defer reporter.TrackFailure(ctx, &err)

	from := opts.SourceFormat
	responseFormat := cliproxyexecutor.ResponseFormatOrSource(opts)
	to := sdktranslator.FromString("antigravity")

	originalPayloadSource := req.Payload
	if len(opts.OriginalRequest) > 0 {
		originalPayloadSource = opts.OriginalRequest
	}
	originalPayload := originalPayloadSource
	originalPayload, errValidate := validateAntigravityRequestSignatures(ctx, baseModel, from, originalPayload)
	if errValidate != nil {
		return nil, errValidate
	}
	req.Payload = originalPayload
	token, updatedAuth, errToken := e.ensureAccessToken(ctx, auth)
	if errToken != nil {
		return nil, errToken
	}
	if updatedAuth != nil {
		auth = updatedAuth
		reporter.UpdateAccessTokenFingerprint(auth)
	}

	originalTranslated, translated := helps.TranslateRequestPairWithCodexMultiAgentV2(ctx, opts.Headers, e.cfg, from, to, baseModel, originalPayload, req.Payload, true)

	translated, err = helps.ApplyThinkingWithSourcePayload(translated, req.Payload, originalPayloadSource, req.Model, from.String(), to.String(), e.Identifier())
	if err != nil {
		return nil, err
	}

	requestedModel := helps.PayloadRequestedModel(opts, req.Model)
	requestPath := helps.PayloadRequestPath(opts)
	translated = helps.ApplyPayloadConfigWithRequest(e.cfg, baseModel, "antigravity", from.String(), "request", translated, originalTranslated, requestedModel, requestPath, opts.Headers)
	translated = e.obfuscateSensitiveWords(translated)
	translated = sanitizeAntigravityGeminiRequestSignatures(baseModel, translated)
	translated, _ = sjson.DeleteBytes(translated, "request.stream")
	reporter.SetTranslatedReasoningEffort(translated, to.String())

	useCredits := cliproxyauth.AntigravityCreditsRequested(ctx) && antigravityCreditsRetryEnabled(e.cfg)

	baseURLs := antigravityBaseURLFallbackOrder(auth)
	httpClient := newAntigravityHTTPClient(ctx, e.cfg, auth, 0)
	httpClient = reporter.TrackHTTPClient(httpClient)

	// Credential retry rounds are owned by the conductor. Keep one upstream
	// attempt per credential so request-retry is not consumed twice.
	attempts := 1

attemptLoop:
	for attempt := 0; attempt < attempts; attempt++ {
		var lastStatus int
		var lastBody []byte
		var lastErr error

		for idx, baseURL := range baseURLs {
			requestPayload := translated
			if useCredits {
				if cp := injectEnabledCreditTypes(translated); len(cp) > 0 {
					requestPayload = cp
					helps.MarkCreditsUsed(ctx)
				}
			}
			replayScope := antigravityReasoningReplayScope{}
			if antigravityUsesReasoningReplayCache(baseModel) {
				var errReplay error
				requestPayload, replayScope, errReplay = prepareAntigravityGeminiReasoningReplayPayload(ctx, baseModel, req, opts, requestPayload)
				if errReplay != nil {
					err = errReplay
					return nil, err
				}
			}
			requestPayload = ensureAntigravityGeminiLeadingUserContent(baseModel, requestPayload)
			httpReq, errReq := e.buildRequest(ctx, auth, token, baseModel, requestPayload, true, opts.Alt, baseURL, helps.DerivedAntigravitySessionID(opts.Metadata, req.Metadata))
			if errReq != nil {
				err = errReq
				return nil, err
			}
			httpResp, errDo := httpClient.Do(httpReq)
			if errDo != nil {
				helps.RecordAPIResponseError(ctx, e.cfg, errDo)
				if errors.Is(errDo, context.Canceled) || errors.Is(errDo, context.DeadlineExceeded) {
					return nil, errDo
				}
				lastStatus = 0
				lastBody = nil
				lastErr = errDo
				if idx+1 < len(baseURLs) {
					log.Debugf("antigravity executor: request error on base url %s, retrying with fallback base url: %s", baseURL, baseURLs[idx+1])
					continue
				}
				err = errDo
				return nil, err
			}
			helps.RecordAPIResponseMetadata(ctx, e.cfg, httpResp.StatusCode, httpResp.Header.Clone())
			if httpResp.StatusCode < http.StatusOK || httpResp.StatusCode >= http.StatusMultipleChoices {
				bodyBytes, errRead := io.ReadAll(httpResp.Body)
				if errClose := httpResp.Body.Close(); errClose != nil {
					log.Errorf("antigravity executor: close response body error: %v", errClose)
				}
				if errRead != nil {
					helps.RecordAPIResponseError(ctx, e.cfg, errRead)
					if errors.Is(errRead, context.Canceled) || errors.Is(errRead, context.DeadlineExceeded) {
						err = errRead
						return nil, err
					}
					if errCtx := ctx.Err(); errCtx != nil {
						err = errCtx
						return nil, err
					}
					lastStatus = 0
					lastBody = nil
					lastErr = errRead
					if idx+1 < len(baseURLs) {
						log.Debugf("antigravity executor: read error on base url %s, retrying with fallback base url: %s", baseURL, baseURLs[idx+1])
						continue
					}
					err = errRead
					return nil, err
				}
				helps.AppendAPIResponseChunk(ctx, e.cfg, bodyBytes)
				if httpResp.StatusCode == http.StatusTooManyRequests {
					decision := decideAntigravity429(bodyBytes)

					switch decision.kind {
					case antigravity429DecisionInstantRetrySameAuth:
						if attempt+1 < attempts {
							if decision.retryAfter != nil && *decision.retryAfter > 0 {
								wait := antigravityInstantRetryDelay(*decision.retryAfter)
								log.Debugf("antigravity executor: instant retry for model %s, waiting %s", baseModel, wait)
								if errWait := antigravityWait(ctx, wait); errWait != nil {
									return nil, errWait
								}
							}
							continue attemptLoop
						}
					case antigravity429DecisionShortCooldownSwitchAuth:
						if decision.retryAfter != nil && *decision.retryAfter > 0 {
							if errMarkCooldown := markAntigravityShortCooldownRequired(ctx, auth, baseModel, time.Now(), *decision.retryAfter); errMarkCooldown != nil {
								err = homeKVUnavailableStatusErr(errMarkCooldown)
								return nil, err
							}
							log.Debugf("antigravity executor: short quota cooldown (%s) for model %s recorded", *decision.retryAfter, baseModel)
						}
					case antigravity429DecisionFullQuotaExhausted:
						if useCredits && antigravityHasExplicitCreditsBalanceExhaustedReason(bodyBytes) {
							markAntigravityCreditsPermanentlyDisabled(auth)
						}
						// No credits logic - just fall through to error return below
					}
				}

				lastStatus = httpResp.StatusCode
				lastBody = append([]byte(nil), bodyBytes...)
				lastErr = nil
				if httpResp.StatusCode == http.StatusTooManyRequests && idx+1 < len(baseURLs) {
					log.Debugf("antigravity executor: rate limited on base url %s, retrying with fallback base url: %s", baseURL, baseURLs[idx+1])
					continue
				}
				if antigravityShouldRetryTransientResourceExhausted429(httpResp.StatusCode, bodyBytes) && attempt+1 < attempts {
					delay := antigravityTransient429RetryDelay(attempt)
					log.Debugf("antigravity executor: transient 429 resource exhausted for model %s, retrying in %s (attempt %d/%d)", baseModel, delay, attempt+1, attempts)
					if errWait := antigravityWait(ctx, delay); errWait != nil {
						return nil, errWait
					}
					continue attemptLoop
				}
				if antigravityShouldRetryNoCapacity(httpResp.StatusCode, bodyBytes) {
					if idx+1 < len(baseURLs) {
						log.Debugf("antigravity executor: no capacity on base url %s, retrying with fallback base url: %s", baseURL, baseURLs[idx+1])
						continue
					}
					if attempt+1 < attempts {
						delay := antigravityNoCapacityRetryDelay(attempt)
						log.Debugf("antigravity executor: no capacity for model %s, retrying in %s (attempt %d/%d)", baseModel, delay, attempt+1, attempts)
						if errWait := antigravityWait(ctx, delay); errWait != nil {
							return nil, errWait
						}
						continue attemptLoop
					}
				}
				if antigravityShouldRetrySoftRateLimit(httpResp.StatusCode, bodyBytes) {
					if attempt+1 < attempts {
						delay := antigravitySoftRateLimitDelay(attempt)
						log.Debugf("antigravity executor: soft rate limit for model %s, retrying in %s (attempt %d/%d)", baseModel, delay, attempt+1, attempts)
						if errWait := antigravityWait(ctx, delay); errWait != nil {
							return nil, errWait
						}
						continue attemptLoop
					}
				}
				if errClear := clearAntigravityReasoningReplayOnInvalidSignature(ctx, replayScope, httpResp.StatusCode, bodyBytes); errClear != nil {
					// Report the upstream failure rather than the cleanup failure.
					logAntigravityReasoningReplayDegraded(replayScope, "invalidate", errClear)
				}
				err = newAntigravityStatusErr(httpResp.StatusCode, bodyBytes)
				return nil, err
			}

			// Stream success
			if useCredits {
				clearAntigravityCreditsFailureState(auth)
			}
			replayAccumulator := newAntigravityReasoningReplayAccumulator(replayScope, requestPayload)
			out := make(chan cliproxyexecutor.StreamChunk)
			go func(resp *http.Response) {
				defer close(out)
				defer func() {
					if errClose := resp.Body.Close(); errClose != nil {
						log.Errorf("antigravity executor: close response line error: %v", errClose)
					}
				}()
				scanner := bufio.NewScanner(resp.Body)
				scanner.Buffer(nil, streamScannerBuffer)
				claudeInputTokens := helps.NewClaudeInputTokenState(from, to, responseFormat, originalPayload)
				var param any
				for scanner.Scan() {
					line := scanner.Bytes()
					helps.AppendAPIResponseChunk(ctx, e.cfg, line)
					if replayAccumulator != nil {
						replayAccumulator.ObserveSSELine(line)
					}

					// Filter usage metadata for all models
					// Only retain usage statistics in the terminal chunk
					line = helps.FilterSSEUsageMetadata(line)

					payload := helps.JSONPayload(line)
					if payload == nil {
						continue
					}

					if detail, ok := helps.ParseAntigravityStreamUsage(payload); ok {
						reporter.Publish(ctx, detail)
					}

					payload = e.resolveWebSearchGroundingURLs(ctx, auth, from, originalPayload, translated, payload)
					chunks := helps.TranslateStreamWithClaudeInputTokens(ctx, to, responseFormat, req.Model, opts.OriginalRequest, translated, bytes.Clone(payload), &param, claudeInputTokens)
					for i := range chunks {
						select {
						case out <- cliproxyexecutor.StreamChunk{Payload: chunks[i]}:
						case <-ctx.Done():
							return
						}
					}
				}
				tail := helps.TranslateStreamWithClaudeInputTokens(ctx, to, responseFormat, req.Model, opts.OriginalRequest, translated, []byte("[DONE]"), &param, claudeInputTokens)
				for i := range tail {
					select {
					case out <- cliproxyexecutor.StreamChunk{Payload: tail[i]}:
					case <-ctx.Done():
						return
					}
				}
				if errScan := scanner.Err(); errScan != nil {
					helps.RecordAPIResponseError(ctx, e.cfg, errScan)
					reporter.PublishFailure(ctx, errScan)
					select {
					case out <- cliproxyexecutor.StreamChunk{Err: errScan}:
					case <-ctx.Done():
					}
				} else {
					if replayAccumulator != nil {
						replayAccumulator.Commit(ctx)
					}
					reporter.EnsurePublished(ctx)
				}
			}(httpResp)
			return &cliproxyexecutor.StreamResult{Headers: httpResp.Header.Clone(), Chunks: out}, nil
		}

		switch {
		case lastStatus != 0:
			err = newAntigravityStatusErr(lastStatus, lastBody)
		case lastErr != nil:
			err = lastErr
		default:
			err = statusErr{code: http.StatusServiceUnavailable, msg: "antigravity executor: no base url available"}
		}
		return nil, err
	}

	return nil, err
}