package openai

import (
	"context"
	"encoding/json"
	"fmt"
	"go.uber.org/zap"
	edgeservice "iop/apps/edge/internal/service"
	"iop/packages/go/streamgate"
	"net/http"
	"os"
	"strings"
	"sync"
	"time"
	"unicode"
)

const (
	streamTraceMetadataKey = "iop_trace_stream"
	streamTraceEnvKey      = "IOP_OPENAI_COMPAT_TRACE_STREAM"
)

type hotPathChatCodecContextKey struct{}

// hotPathChatOuterCodec is the caller-owned Chat wire boundary for one HTTP
// turn. Provider protocol decoding stays in the shared Hot Path stage
// decoders; this codec sees only the normalized outer-turn accumulator and
// renders one Chat response identity, one choice/tool index space, aggregate
// usage, and one terminal sequence.
type hotPathChatOuterCodec struct {
	stream         bool
	model          string
	outputCapToken int

	mu         sync.Mutex
	outer      *hotPathOuterTurn
	rendered   bool
	writer     http.ResponseWriter
	flusher    http.Flusher
	opened     bool
	responseID string
	created    int64
	toolIndex  map[string]int
}

func newHotPathChatOuterCodec(stream bool, model string, outputCapToken int) *hotPathChatOuterCodec {
	if outputCapToken < 0 {
		outputCapToken = 0
	}
	return &hotPathChatOuterCodec{
		stream:         stream,
		model:          strings.TrimSpace(model),
		outputCapToken: outputCapToken,
	}
}

func withHotPathChatOuterCodec(r *http.Request, codec *hotPathChatOuterCodec) *http.Request {
	if r == nil || codec == nil {
		return r
	}
	return r.WithContext(context.WithValue(r.Context(), hotPathChatCodecContextKey{}, codec))
}

func hotPathChatOuterCodecFromRequest(r *http.Request) *hotPathChatOuterCodec {
	if r == nil {
		return nil
	}
	codec, _ := r.Context().Value(hotPathChatCodecContextKey{}).(*hotPathChatOuterCodec)
	return codec
}

// callerOuterTurn returns the request-local outer sequencer fixed by the Chat
// handler. The first caller supplies the public identity. Later stages in the
// same HTTP turn reuse the exact object, so stage changes cannot reset tool
// indexes, usage, or the caller cap.
func (c *hotPathChatOuterCodec) callerOuterTurn(responseID string, outputCapToken int) *hotPathOuterTurn {
	if c == nil {
		return newHotPathCallerCappedOuterTurn(responseID, outputCapToken)
	}
	c.mu.Lock()
	defer c.mu.Unlock()
	if c.outer == nil {
		capToken := c.outputCapToken
		if capToken <= 0 {
			capToken = outputCapToken
		}
		c.outer = newHotPathCallerCappedOuterTurn(responseID, capToken)
	}
	return c.outer
}

func (c *hotPathChatOuterCodec) currentOuterTurn() *hotPathOuterTurn {
	if c == nil {
		return nil
	}
	c.mu.Lock()
	defer c.mu.Unlock()
	return c.outer
}

// prepareProgressiveWriter attaches the caller writer before an already-
// classified Light stage starts. The callback is invoked outside the outer
// turn mutex and writes identity-safe text, reasoning, and tool deltas
// immediately. The Light outer allocates each caller tool ID before release;
// the single finish/usage/[DONE] sequence remains owned by writeResponse.
func (c *hotPathChatOuterCodec) prepareProgressiveWriter(w http.ResponseWriter, outer *hotPathOuterTurn) error {
	if c == nil || !c.stream || outer == nil {
		return nil
	}
	flusher, ok := w.(http.Flusher)
	if !ok {
		return fmt.Errorf("response writer does not support flushing")
	}
	c.mu.Lock()
	c.writer = w
	c.flusher = flusher
	c.mu.Unlock()
	return outer.setReleaseCallback(func(delta hotPathReleasedDelta) error {
		return c.writeProgressiveDelta(outer, delta)
	})
}

func (c *hotPathChatOuterCodec) writeProgressiveDelta(outer *hotPathOuterTurn, delta hotPathReleasedDelta) error {
	responseID, ok := outer.publicResponseIdentity()
	if !ok {
		return fmt.Errorf("Chat outer response is missing provider execution identity")
	}
	c.mu.Lock()
	defer c.mu.Unlock()
	if c.rendered {
		return errHotPathTurnTerminal
	}
	if err := c.ensureStreamOpenLocked(responseID, 0); err != nil {
		return err
	}
	switch delta.Kind {
	case streamgate.EventKindReasoningDelta:
		return c.emitChunkLocked(map[string]any{"reasoning_content": delta.Text}, "", nil)
	case streamgate.EventKindTextDelta:
		return c.emitChunkLocked(map[string]any{"content": delta.Text}, "", nil)
	case streamgate.EventKindToolCallFragment:
		if c.toolIndex == nil {
			c.toolIndex = make(map[string]int)
		}
		index, exists := c.toolIndex[delta.PublicID]
		if !exists {
			index = len(c.toolIndex)
			c.toolIndex[delta.PublicID] = index
		}
		function := map[string]any{"arguments": delta.Args}
		tool := map[string]any{"index": index, "function": function}
		if !exists {
			tool["id"] = delta.PublicID
			tool["type"] = "function"
		}
		if delta.Name != "" {
			function["name"] = delta.Name
		}
		return c.emitChunkLocked(map[string]any{"tool_calls": []any{tool}}, "", nil)
	default:
		return fmt.Errorf("unsupported progressive Chat delta kind %q", delta.Kind)
	}
}

// hotPathCallerOuterTurn keeps the shared runner endpoint-neutral while each
// public endpoint owns its caller codec.
func hotPathCallerOuterTurn(r *http.Request, protocol, responseID string, outputCapToken int) *hotPathOuterTurn {
	if protocol == "openai" {
		if codec := hotPathChatOuterCodecFromRequest(r); codec != nil {
			return codec.callerOuterTurn(responseID, outputCapToken)
		}
	}
	if protocol == "anthropic" {
		if codec := hotPathAnthropicCodecFromRequest(r); codec != nil {
			return codec.callerOuterTurn(responseID, outputCapToken)
		}
	}
	return newHotPathCallerCappedOuterTurn(responseID, outputCapToken)
}

// runInitialPresetTurn consumes the result returned by the handler's existing
// one-shot provider-pool admission. It never submits or redispatches a selector
// attempt. The boolean distinguishes collection failures (no caller response
// has been rendered) from shared-turn failures that already own their endpoint
// response.
func (c *hotPathChatOuterCodec) runInitialPresetTurn(
	s *Server,
	w http.ResponseWriter,
	r *http.Request,
	dispatch routeDispatch,
	runMeta map[string]string,
	result *edgeservice.ProviderPoolDispatchResult,
) (normalizedStageOutput, bool, error) {
	stage, gate, err := s.collectPresetSelectorResult(r.Context(), dispatch, "openai", result)
	if err != nil {
		if contextErr := r.Context().Err(); contextErr != nil {
			// The active-stage owner already propagated exact cancellation. Mark
			// the turn as consumed so the handler does not synthesize response
			// bytes after the caller has gone away.
			return stage, true, contextErr
		}
		return stage, false, err
	}
	err = s.dispatchPresetTurn(w, r, dispatch, "openai", c.stream, runMeta, stage, gate)
	return stage, true, err
}

func writeHotPathChatOuterResponse(turn *hotPathTurn, output normalizedStageOutput) (bool, error) {
	if turn == nil {
		return false, nil
	}
	codec := hotPathChatOuterCodecFromRequest(turn.Request)
	if codec == nil {
		return false, nil
	}
	return true, codec.writeResponse(turn, output)
}

func writeHotPathChatOuterError(
	turn *hotPathTurn,
	status int,
	errorType, message string,
	disposition hotPathTerminalDisposition,
) bool {
	if turn == nil {
		return false
	}
	codec := hotPathChatOuterCodecFromRequest(turn.Request)
	if codec == nil {
		return false
	}
	_ = codec.writeDisposition(turn.Writer, disposition, status, errorType, message)
	return true
}

func (c *hotPathChatOuterCodec) writeResponse(turn *hotPathTurn, output normalizedStageOutput) error {
	model := c.model
	if model == "" {
		model = directPublicModel(turn)
	}
	responseID := strings.TrimSpace(output.ResponseID)
	outer := c.currentOuterTurn()
	finishReason := openAIDirectFinishReason(output.TerminalReason)
	if outer != nil {
		if bound, ok := outer.publicResponseIdentity(); ok {
			responseID = bound
		}
		if disposition, ok := outer.terminalDisposition(); ok {
			policy := chatHotPathPolicy(disposition)
			switch {
			case policy.silent && outer.isTerminalCommitted():
				return c.writeDisposition(turn.Writer, disposition, 0, "", "")
			case policy.errorTerminal && outer.isTerminalCommitted():
				return c.writeDisposition(
					turn.Writer, disposition, policy.status, policy.errorType, disposition.Cause,
				)
			case policy.finishReason != "":
				finishReason = policy.finishReason
			}
		}
	}
	if responseID == "" {
		return fmt.Errorf("Chat outer response is missing provider execution identity")
	}

	if finishReason == "" {
		if len(output.ToolCalls) > 0 {
			finishReason = "tool_calls"
		} else {
			finishReason = "stop"
		}
	}

	if !c.stream {
		c.mu.Lock()
		if c.rendered {
			c.mu.Unlock()
			return errHotPathTurnTerminal
		}
		c.rendered = true
		c.mu.Unlock()
		response := map[string]any{
			"id": responseID, "object": "chat.completion", "created": output.Created, "model": model,
			"choices": []any{map[string]any{
				"index": 0, "message": openAIDirectMessage(output), "finish_reason": finishReason,
			}},
		}
		if len(output.Usage) > 0 {
			response["usage"] = output.Usage
		}
		return writeDirectJSON(turn.Writer, http.StatusOK, response)
	}

	c.mu.Lock()
	defer c.mu.Unlock()
	if c.rendered {
		return errHotPathTurnTerminal
	}
	c.rendered = true
	c.model = model
	if c.writer == nil {
		flusher, ok := turn.Writer.(http.Flusher)
		if !ok {
			return fmt.Errorf("response writer does not support flushing")
		}
		c.writer = turn.Writer
		c.flusher = flusher
	}
	openedBeforeTerminal := c.opened
	if err := c.ensureStreamOpenLocked(responseID, output.Created); err != nil {
		return err
	}
	released := []hotPathReleasedDelta(nil)
	if outer != nil && !output.CallerStageOnly {
		released = outer.releasedDeltas()
	}
	emittedContent, emittedReasoning := false, false
	emittedTools := make([]bool, len(output.ToolCalls))
	toolFragments := hotPathChatToolArgumentFragments(released, output.ToolCalls)
	toolIndexes := make(map[string]int, len(output.ToolCalls))
	nextToolIndex := 0
	toolFragmentIndexes := make([]int, len(output.ToolCalls))
	for _, delta := range released {
		switch delta.Kind {
		case streamgate.EventKindReasoningDelta:
			if openedBeforeTerminal {
				continue
			}
			emittedReasoning = true
			if err := c.emitChunkLocked(map[string]any{"reasoning_content": delta.Text}, "", nil); err != nil {
				return err
			}
		case streamgate.EventKindTextDelta:
			if openedBeforeTerminal {
				continue
			}
			emittedContent = true
			if err := c.emitChunkLocked(map[string]any{"content": delta.Text}, "", nil); err != nil {
				return err
			}
		case streamgate.EventKindToolCallFragment:
			if openedBeforeTerminal {
				continue
			}
			index, ok := toolIndexes[delta.PublicID]
			if !ok {
				index = nextToolIndex
				nextToolIndex++
				toolIndexes[delta.PublicID] = index
			}
			if index >= len(output.ToolCalls) || toolFragments[index] == nil {
				continue
			}
			fragmentIndex := toolFragmentIndexes[index]
			if fragmentIndex >= len(toolFragments[index]) {
				continue
			}
			call := output.ToolCalls[index]
			function := map[string]any{"arguments": toolFragments[index][fragmentIndex]}
			tool := map[string]any{"index": index, "function": function}
			if fragmentIndex == 0 {
				tool["id"] = call.ID
				tool["type"] = "function"
				function["name"] = call.Name
			}
			if err := c.emitChunkLocked(map[string]any{"tool_calls": []any{tool}}, "", nil); err != nil {
				return err
			}
			if c.toolIndex == nil {
				c.toolIndex = make(map[string]int)
			}
			c.toolIndex[call.ID] = index
			toolFragmentIndexes[index]++
			emittedTools[index] = true
		}
	}
	if !openedBeforeTerminal && !emittedReasoning {
		if output.Reasoning != "" {
			if err := c.emitChunkLocked(map[string]any{"reasoning_content": output.Reasoning}, "", nil); err != nil {
				return err
			}
		}
	}
	if !openedBeforeTerminal && !emittedContent {
		if output.Content != "" {
			if err := c.emitChunkLocked(map[string]any{"content": output.Content}, "", nil); err != nil {
				return err
			}
		}
	}

	for index, call := range output.ToolCalls {
		_, progressivelyEmitted := c.toolIndex[call.ID]
		if emittedTools[index] || progressivelyEmitted {
			continue
		}
		first := map[string]any{
			"index": index, "id": call.ID, "type": "function",
			"function": map[string]any{"name": call.Name, "arguments": directToolArguments(call)},
		}
		if err := c.emitChunkLocked(map[string]any{"tool_calls": []any{first}}, "", nil); err != nil {
			return err
		}
	}
	if err := c.emitChunkLocked(map[string]any{}, finishReason, output.Usage); err != nil {
		return err
	}
	if _, err := fmt.Fprint(c.writer, "data: [DONE]\n\n"); err != nil {
		return err
	}
	c.flusher.Flush()
	return nil
}

func (c *hotPathChatOuterCodec) ensureStreamOpenLocked(responseID string, created int64) error {
	if c.opened {
		if c.responseID != responseID {
			return fmt.Errorf("Chat outer response identity changed after commitment")
		}
		return nil
	}
	if c.writer == nil || c.flusher == nil {
		return fmt.Errorf("Chat progressive writer is unavailable")
	}
	if created == 0 {
		created = time.Now().Unix()
	}
	c.responseID = responseID
	c.created = created
	c.writer.Header().Set("Content-Type", "text/event-stream")
	c.writer.Header().Set("Cache-Control", "no-cache")
	c.writer.Header().Set("Connection", "keep-alive")
	c.writer.WriteHeader(http.StatusOK)
	c.opened = true
	return c.emitChunkLocked(map[string]any{"role": "assistant"}, "", nil)
}

func (c *hotPathChatOuterCodec) emitChunkLocked(delta map[string]any, reason string, usage json.RawMessage) error {
	choice := map[string]any{"index": 0, "delta": delta, "finish_reason": nil}
	if reason != "" {
		choice["finish_reason"] = reason
	}
	chunk := map[string]any{
		"id": c.responseID, "object": "chat.completion.chunk", "created": c.created,
		"model": c.model, "choices": []any{choice},
	}
	if len(usage) > 0 {
		chunk["usage"] = usage
	}
	return writeDirectSSEData(c.writer, c.flusher, chunk)
}

// writeDisposition renders an error or caller cancellation according to the
// response commit state. Before commitment, Chat keeps the ordinary JSON
// status contract. After the role/delta stream is open, it emits one standard
// error envelope as SSE data followed by exactly one [DONE]. Caller
// cancellation marks the codec terminal without writing any additional byte.
func (c *hotPathChatOuterCodec) writeDisposition(
	w http.ResponseWriter,
	disposition hotPathTerminalDisposition,
	status int,
	errorType, message string,
) error {
	if c == nil || w == nil {
		return fmt.Errorf("Chat Hot Path codec is unavailable")
	}
	policy := chatHotPathPolicy(disposition)
	if policy.status != 0 {
		status = policy.status
	}
	if policy.errorType != "" {
		errorType = policy.errorType
	}
	if strings.TrimSpace(message) == "" {
		message = hotPathFirstNonEmpty(disposition.Cause, "hot path stage failed")
	}

	c.mu.Lock()
	defer c.mu.Unlock()
	if c.rendered {
		return errHotPathTurnTerminal
	}
	c.rendered = true
	if policy.silent {
		return nil
	}
	if !policy.errorTerminal {
		return fmt.Errorf("Chat disposition %q is not an error terminal", disposition.Kind)
	}
	if !c.stream || !c.opened {
		writeError(w, status, errorType, message)
		return nil
	}
	if c.writer == nil || c.flusher == nil {
		return fmt.Errorf("Chat progressive writer is unavailable")
	}
	if err := writeDirectSSEData(c.writer, c.flusher, errorResponse{
		Error: errorBody{Type: errorType, Message: message},
	}); err != nil {
		return err
	}
	if _, err := fmt.Fprint(c.writer, "data: [DONE]\n\n"); err != nil {
		return err
	}
	c.flusher.Flush()
	return nil
}

// hotPathChatToolArgumentFragments projects the normalized release stream onto
// the final mapped tool order. Logical-request mapping may replace public tool
// ids after release, so ordering—not an obsolete pre-projection id—is the
// stable join key. A mismatch falls back to the final assembled arguments.
func hotPathChatToolArgumentFragments(released []hotPathReleasedDelta, calls []normalizedToolCall) [][]string {
	fragments := make([][]string, len(calls))
	if len(calls) == 0 {
		return fragments
	}
	order := make([]string, 0, len(calls))
	byID := make(map[string]int, len(calls))
	for _, delta := range released {
		if delta.Kind != streamgate.EventKindToolCallFragment {
			continue
		}
		index, ok := byID[delta.PublicID]
		if !ok {
			index = len(order)
			if index >= len(calls) {
				continue
			}
			byID[delta.PublicID] = index
			order = append(order, delta.PublicID)
		}
		fragments[index] = append(fragments[index], delta.Args)
	}
	for index, call := range calls {
		if strings.Join(fragments[index], "") != directToolArguments(call) {
			fragments[index] = nil
		}
	}
	return fragments
}

func (s *Server) streamChatCompletion(w http.ResponseWriter, dc *chatDispatchContext, handle edgeservice.RunResult) {
	flusher, ok := w.(http.Flusher)
	if !ok {
		handle.Close()
		dc.finishUsageRequest(usageStatusError, responseModeNormalized)
		writeError(w, http.StatusInternalServerError, "streaming_not_supported", "response writer does not support streaming")
		return
	}

	// Buffered streams collect and validate the full response before emitting
	// user-visible chunks. Strict buffered output opts in explicitly, and
	// tool-bearing streams use the same path so malformed tool calls can be
	// retried or rejected before reaching a client tool runner.
	if (dc.outputPolicy.Strict && dc.outputPolicy.StreamBuffer) || len(dc.req.Tools) > 0 {
		s.streamBufferedChatCompletion(w, dc, handle, flusher)
		return
	}

	// The Core request runtime owns response-start/role
	// staging and commits status/header/role only at first safe release. A
	// provider-pool dispatch is included: its initial admission result is
	// handed to the runtime as the initial attempt binding, and every recovery
	// re-enters SubmitProviderPool through the same request runtime.
	s.runOpenAIChatStreamGate(w, flusher, dc, handle)
}

// streamChatCompletionLegacy preserves the stage-level compatibility seam used
// by focused tests that construct a dispatch context without the ingress
// snapshot required by the request runtime. Production handlers always provide
// that snapshot and therefore never enter this helper.
func (s *Server) streamChatCompletionLegacy(w http.ResponseWriter, flusher http.Flusher, dc *chatDispatchContext, handle edgeservice.RunResult) {
	w.Header().Set("Content-Type", "text/event-stream")
	w.Header().Set("Cache-Control", "no-cache")
	w.Header().Set("Connection", "keep-alive")

	defer handle.Close()
	sess := s.newChatStreamSession(w, flusher, dc.req, dc.submitReq, handle, dc.outputPolicy, dc.usage)
	sess.writeRole()
	defer sess.logClosed()

	stream := handle.Stream()
	if stream.Events == nil {
		sess.failStream("run stream unavailable")
		return
	}
	sess.consume(dc.r, stream, handle.WaitTimeout())
}

// consume drives the session until it reaches a terminal state: a terminal run
// event, a node disconnect, a caller cancel, or the run wait timeout.
func (sess *chatStreamSession) consume(r *http.Request, stream edgeservice.RunStream, waitTimeout time.Duration) {
	for {
		select {
		case <-r.Context().Done():
			sess.cancel(r.Context().Err(), usageStatusForError(r.Context().Err()), false)
			return
		case nodeEvent, ok := <-stream.NodeEvents:
			if !ok {
				stream.NodeEvents = nil
				continue
			}
			if edgeservice.IsNodeDisconnected(nodeEvent) {
				sess.fail("node disconnected")
				return
			}
		case event, ok := <-stream.Events:
			if !ok {
				sess.failStream("run stream closed")
				return
			}
			if sess.consumeEvent(event) {
				return
			}
		case <-time.After(waitTimeout):
			sess.cancel(errRunTimedOut, usageStatusCancel, true)
			return
		}
	}
}

type streamToolTextFilter struct {
	pending string
}

func (f *streamToolTextFilter) Append(delta string) string {
	f.pending += delta
	if idx := firstStreamToolTextCandidateIndex(f.pending); idx >= 0 {
		out := strings.TrimRightFunc(f.pending[:idx], unicode.IsSpace)
		f.pending = f.pending[idx:]
		return out
	}
	flushLen := streamToolTextSafeFlushLen(f.pending)
	out := strings.TrimRightFunc(f.pending[:flushLen], unicode.IsSpace)
	f.pending = f.pending[len(out):]
	return out
}

func (f *streamToolTextFilter) Flush() string {
	out := f.pending
	f.pending = ""
	return out
}

func (f *streamToolTextFilter) FlushNonCandidate() string {
	if firstStreamToolTextCandidateIndex(f.pending) >= 0 {
		f.pending = ""
		return ""
	}
	// Even without a full candidate, chunk-boundary protection can leave a
	// partial candidate suffix (e.g. "<tool_ca", trailing "{") in pending.
	// Return only the safe non-candidate prefix and drop the partial suffix so
	// a native tool_calls completion never flushes a raw candidate fragment.
	flushLen := streamToolTextSafeFlushLen(f.pending)
	out := strings.TrimRightFunc(f.pending[:flushLen], unicode.IsSpace)
	f.pending = ""
	return out
}

func firstStreamToolTextCandidateIndex(s string) int {
	xml := strings.Index(strings.ToLower(s), "<tool_call")
	mustache := strings.Index(s, textMustacheToolCallOpenHint)
	switch {
	case xml < 0:
		return mustache
	case mustache < 0:
		return xml
	case xml < mustache:
		return xml
	default:
		return mustache
	}
}

func streamToolTextSafeFlushLen(s string) int {
	if s == "" {
		return 0
	}
	const xmlHint = "<tool_call"
	lower := strings.ToLower(s)
	start := len(s) - len(xmlHint) + 1
	if start < 0 {
		start = 0
	}
	for i := start; i < len(s); i++ {
		if strings.HasPrefix(xmlHint, lower[i:]) ||
			strings.HasPrefix(textMustacheToolCallOpenHint, s[i:]) {
			return i
		}
	}
	return len(s)
}

func unstreamedCleanedText(cleaned, emitted string) string {
	if cleaned == "" {
		return ""
	}
	if emitted == "" {
		return cleaned
	}
	if strings.HasPrefix(cleaned, emitted) {
		return cleaned[len(emitted):]
	}
	cleaned = strings.TrimSpace(cleaned)
	emitted = strings.TrimSpace(emitted)
	if cleaned == "" || cleaned == emitted {
		return ""
	}
	if emitted != "" && strings.HasPrefix(cleaned, emitted) {
		return strings.TrimSpace(strings.TrimPrefix(cleaned, emitted))
	}
	return ""
}

func openAICompatTraceStreamEnabled(metadata map[string]string) bool {
	if traceBool(os.Getenv(streamTraceEnvKey)) {
		return true
	}
	if metadata == nil {
		return false
	}
	return traceBool(metadata[streamTraceMetadataKey])
}

func traceBool(v string) bool {
	switch strings.ToLower(strings.TrimSpace(v)) {
	case "1", "true", "yes", "on":
		return true
	default:
		return false
	}
}

func logOpenAICompatStreamOutput(logger *zap.Logger, runID string, seq int, typ string, delta string, extra ...zap.Field) {
	fields := []zap.Field{
		zap.String("run_id", runID),
		zap.Int("seq", seq),
		zap.String("type", typ),
		zap.Int("delta_len", len(delta)),
		zap.Bool("delta_has_open_think", hasOpenThinkTag(delta)),
		zap.Bool("delta_has_close_think", hasCloseThinkTag(delta)),
	}
	fields = append(fields, extra...)
	logger.Info("openai chat completion stream output chunk", fields...)
}

func hasOpenThinkTag(s string) bool {
	return strings.Contains(strings.ToLower(s), "<think")
}

func hasCloseThinkTag(s string) bool {
	return strings.Contains(strings.ToLower(s), "</think")
}