package executor

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

	codexauth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth/codex"
	"github.com/router-for-me/CLIProxyAPI/v6/internal/config"
	"github.com/router-for-me/CLIProxyAPI/v6/internal/misc"
	"github.com/router-for-me/CLIProxyAPI/v6/internal/util"
	cliproxyauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
	cliproxyexecutor "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/executor"
	sdktranslator "github.com/router-for-me/CLIProxyAPI/v6/sdk/translator"
	log "github.com/sirupsen/logrus"
	"github.com/tidwall/gjson"
	"github.com/tidwall/sjson"
	"github.com/tiktoken-go/tokenizer"

	"github.com/gin-gonic/gin"
	"github.com/google/uuid"
)

var dataTag = []byte("data:")

// CodexExecutor is a stateless executor for Codex (OpenAI Responses API entrypoint).
// If api_key is unavailable on auth, it falls back to legacy via ClientAdapter.
type CodexExecutor struct {
	cfg *config.Config
}

func NewCodexExecutor(cfg *config.Config) *CodexExecutor { return &CodexExecutor{cfg: cfg} }

func (e *CodexExecutor) Identifier() string { return "codex" }

func (e *CodexExecutor) PrepareRequest(_ *http.Request, _ *cliproxyauth.Auth) error { return nil }

func (e *CodexExecutor) Execute(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (resp cliproxyexecutor.Response, err error) {
	apiKey, baseURL := codexCreds(auth)

	if baseURL == "" {
		baseURL = "https://chatgpt.com/backend-api/codex"
	}
	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
	defer reporter.trackFailure(ctx, &err)

	model := req.Model
	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
		model = override
	}

	from := opts.SourceFormat
	to := sdktranslator.FromString("codex")
	originalPayload := bytes.Clone(req.Payload)
	if len(opts.OriginalRequest) > 0 {
		originalPayload = bytes.Clone(opts.OriginalRequest)
	}
	originalTranslated := sdktranslator.TranslateRequest(from, to, model, originalPayload, false)
	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)
	body = ApplyReasoningEffortMetadata(body, req.Metadata, model, "reasoning.effort", false)
	body = NormalizeThinkingConfig(body, model, false)
	if errValidate := ValidateThinkingConfig(body, model); errValidate != nil {
		return resp, errValidate
	}
	body = applyPayloadConfigWithRoot(e.cfg, model, to.String(), "", body, originalTranslated)
	body, _ = sjson.SetBytes(body, "model", model)
	body, _ = sjson.SetBytes(body, "stream", true)
	body, _ = sjson.DeleteBytes(body, "previous_response_id")

	url := strings.TrimSuffix(baseURL, "/") + "/responses"
	httpReq, err := e.cacheHelper(ctx, from, url, req, body)
	if err != nil {
		return resp, err
	}
	applyCodexHeaders(httpReq, auth, apiKey)
	var authID, authLabel, authType, authValue string
	if auth != nil {
		authID = auth.ID
		authLabel = auth.Label
		authType, authValue = auth.AccountInfo()
	}
	recordAPIRequest(ctx, e.cfg, upstreamRequestLog{
		URL:       url,
		Method:    http.MethodPost,
		Headers:   httpReq.Header.Clone(),
		Body:      body,
		Provider:  e.Identifier(),
		AuthID:    authID,
		AuthLabel: authLabel,
		AuthType:  authType,
		AuthValue: authValue,
	})
	httpClient := newProxyAwareHTTPClient(ctx, e.cfg, auth, 0)
	httpResp, err := httpClient.Do(httpReq)
	if err != nil {
		recordAPIResponseError(ctx, e.cfg, err)
		return resp, err
	}
	defer func() {
		if errClose := httpResp.Body.Close(); errClose != nil {
			log.Errorf("codex executor: close response body error: %v", errClose)
		}
	}()
	recordAPIResponseMetadata(ctx, e.cfg, httpResp.StatusCode, httpResp.Header.Clone())
	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
		b, _ := io.ReadAll(httpResp.Body)
		appendAPIResponseChunk(ctx, e.cfg, b)
		log.Warnf("codex executor: upstream API error, status: %d, body: %s", httpResp.StatusCode, summarizeErrorBody(httpResp.Header.Get("Content-Type"), b))
		err = statusErr{code: httpResp.StatusCode, msg: string(b)}
		return resp, err
	}
	data, err := io.ReadAll(httpResp.Body)
	if err != nil {
		recordAPIResponseError(ctx, e.cfg, err)
		return resp, err
	}
	appendAPIResponseChunk(ctx, e.cfg, data)

	lines := bytes.Split(data, []byte("\n"))
	for _, line := range lines {
		if !bytes.HasPrefix(line, dataTag) {
			continue
		}

		line = bytes.TrimSpace(line[5:])
		if gjson.GetBytes(line, "type").String() != "response.completed" {
			continue
		}

		if detail, ok := parseCodexUsage(line); ok {
			reporter.publish(ctx, detail)
		}

		var param any
		out := sdktranslator.TranslateNonStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, line, &param)
		resp = cliproxyexecutor.Response{Payload: []byte(out)}
		return resp, nil
	}
	err = statusErr{code: 408, msg: "stream error: stream disconnected before completion: stream closed before response.completed"}
	return resp, err
}

func (e *CodexExecutor) ExecuteStream(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (stream <-chan cliproxyexecutor.StreamChunk, err error) {
	apiKey, baseURL := codexCreds(auth)

	if baseURL == "" {
		baseURL = "https://chatgpt.com/backend-api/codex"
	}
	reporter := newUsageReporter(ctx, e.Identifier(), req.Model, auth)
	defer reporter.trackFailure(ctx, &err)

	model := req.Model
	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
		model = override
	}

	from := opts.SourceFormat
	to := sdktranslator.FromString("codex")
	originalPayload := bytes.Clone(req.Payload)
	if len(opts.OriginalRequest) > 0 {
		originalPayload = bytes.Clone(opts.OriginalRequest)
	}
	originalTranslated := sdktranslator.TranslateRequest(from, to, model, originalPayload, true)
	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), true)

	body = ApplyReasoningEffortMetadata(body, req.Metadata, model, "reasoning.effort", false)
	body = NormalizeThinkingConfig(body, model, false)
	if errValidate := ValidateThinkingConfig(body, model); errValidate != nil {
		return nil, errValidate
	}
	body = applyPayloadConfigWithRoot(e.cfg, model, to.String(), "", body, originalTranslated)
	body, _ = sjson.DeleteBytes(body, "previous_response_id")
	body, _ = sjson.SetBytes(body, "model", model)

	url := strings.TrimSuffix(baseURL, "/") + "/responses"
	httpReq, err := e.cacheHelper(ctx, from, url, req, body)
	if err != nil {
		return nil, err
	}
	applyCodexHeaders(httpReq, auth, apiKey)
	var authID, authLabel, authType, authValue string
	if auth != nil {
		authID = auth.ID
		authLabel = auth.Label
		authType, authValue = auth.AccountInfo()
	}
	recordAPIRequest(ctx, e.cfg, upstreamRequestLog{
		URL:       url,
		Method:    http.MethodPost,
		Headers:   httpReq.Header.Clone(),
		Body:      body,
		Provider:  e.Identifier(),
		AuthID:    authID,
		AuthLabel: authLabel,
		AuthType:  authType,
		AuthValue: authValue,
	})

	httpClient := newProxyAwareHTTPClient(ctx, e.cfg, auth, 0)
	httpResp, err := httpClient.Do(httpReq)
	if err != nil {
		recordAPIResponseError(ctx, e.cfg, err)
		return nil, err
	}
	recordAPIResponseMetadata(ctx, e.cfg, httpResp.StatusCode, httpResp.Header.Clone())
	if httpResp.StatusCode < 200 || httpResp.StatusCode >= 300 {
		data, readErr := io.ReadAll(httpResp.Body)
		if errClose := httpResp.Body.Close(); errClose != nil {
			log.Errorf("codex executor: close response body error: %v", errClose)
		}
		if readErr != nil {
			recordAPIResponseError(ctx, e.cfg, readErr)
			return nil, readErr
		}
		appendAPIResponseChunk(ctx, e.cfg, data)
		log.Warnf("codex executor: upstream API error (stream), status: %d, body: %s", httpResp.StatusCode, summarizeErrorBody(httpResp.Header.Get("Content-Type"), data))
		err = statusErr{code: httpResp.StatusCode, msg: string(data)}
		return nil, err
	}
	out := make(chan cliproxyexecutor.StreamChunk)
	stream = out
	go func() {
		defer close(out)
		defer func() {
			if errClose := httpResp.Body.Close(); errClose != nil {
				log.Errorf("codex executor: close response body error: %v", errClose)
			}
		}()
		scanner := bufio.NewScanner(httpResp.Body)
		scanner.Buffer(nil, 52_428_800) // 50MB
		var param any
		for scanner.Scan() {
			line := scanner.Bytes()
			appendAPIResponseChunk(ctx, e.cfg, line)

			if bytes.HasPrefix(line, dataTag) {
				data := bytes.TrimSpace(line[5:])
				if gjson.GetBytes(data, "type").String() == "response.completed" {
					if detail, ok := parseCodexUsage(data); ok {
						reporter.publish(ctx, detail)
					}
				}
			}

			chunks := sdktranslator.TranslateStream(ctx, to, from, req.Model, bytes.Clone(opts.OriginalRequest), body, bytes.Clone(line), &param)
			for i := range chunks {
				out <- cliproxyexecutor.StreamChunk{Payload: []byte(chunks[i])}
			}
		}
		if errScan := scanner.Err(); errScan != nil {
			recordAPIResponseError(ctx, e.cfg, errScan)
			reporter.publishFailure(ctx)
			out <- cliproxyexecutor.StreamChunk{Err: errScan}
		}
	}()
	return stream, nil
}

func (e *CodexExecutor) CountTokens(ctx context.Context, auth *cliproxyauth.Auth, req cliproxyexecutor.Request, opts cliproxyexecutor.Options) (cliproxyexecutor.Response, error) {
	model := req.Model
	if override := e.resolveUpstreamModel(req.Model, auth); override != "" {
		model = override
	}

	from := opts.SourceFormat
	to := sdktranslator.FromString("codex")
	body := sdktranslator.TranslateRequest(from, to, model, bytes.Clone(req.Payload), false)

	body = ApplyReasoningEffortMetadata(body, req.Metadata, model, "reasoning.effort", false)
	body, _ = sjson.SetBytes(body, "model", model)
	body, _ = sjson.DeleteBytes(body, "previous_response_id")
	body, _ = sjson.SetBytes(body, "stream", false)

	enc, err := tokenizerForCodexModel(model)
	if err != nil {
		return cliproxyexecutor.Response{}, fmt.Errorf("codex executor: tokenizer init failed: %w", err)
	}

	count, err := countCodexInputTokens(enc, body)
	if err != nil {
		return cliproxyexecutor.Response{}, fmt.Errorf("codex executor: token counting failed: %w", err)
	}

	usageJSON := fmt.Sprintf(`{"response":{"usage":{"input_tokens":%d,"output_tokens":0,"total_tokens":%d}}}`, count, count)
	translated := sdktranslator.TranslateTokenCount(ctx, to, from, count, []byte(usageJSON))
	return cliproxyexecutor.Response{Payload: []byte(translated)}, nil
}

func tokenizerForCodexModel(model string) (tokenizer.Codec, error) {
	sanitized := strings.ToLower(strings.TrimSpace(model))
	switch {
	case sanitized == "":
		return tokenizer.Get(tokenizer.Cl100kBase)
	case strings.HasPrefix(sanitized, "gpt-5"):
		return tokenizer.Get(tokenizer.Cl100kBase)
	case strings.HasPrefix(sanitized, "gpt-4.1"):
		return tokenizer.Get(tokenizer.Cl100kBase)
	case strings.HasPrefix(sanitized, "gpt-4o"):
		return tokenizer.ForModel(tokenizer.GPT4o)
	case strings.HasPrefix(sanitized, "gpt-4"):
		return tokenizer.ForModel(tokenizer.GPT4)
	case strings.HasPrefix(sanitized, "gpt-3.5"), strings.HasPrefix(sanitized, "gpt-3"):
		return tokenizer.ForModel(tokenizer.GPT35Turbo)
	default:
		return tokenizer.Get(tokenizer.Cl100kBase)
	}
}

func countCodexInputTokens(enc tokenizer.Codec, body []byte) (int64, error) {
	if enc == nil {
		return 0, fmt.Errorf("encoder is nil")
	}
	if len(body) == 0 {
		return 0, nil
	}

	root := gjson.ParseBytes(body)
	var segments []string

	if inst := strings.TrimSpace(root.Get("instructions").String()); inst != "" {
		segments = append(segments, inst)
	}

	inputItems := root.Get("input")
	if inputItems.IsArray() {
		arr := inputItems.Array()
		for i := range arr {
			item := arr[i]
			switch item.Get("type").String() {
			case "message":
				content := item.Get("content")
				if content.IsArray() {
					parts := content.Array()
					for j := range parts {
						part := parts[j]
						if text := strings.TrimSpace(part.Get("text").String()); text != "" {
							segments = append(segments, text)
						}
					}
				}
			case "function_call":
				if name := strings.TrimSpace(item.Get("name").String()); name != "" {
					segments = append(segments, name)
				}
				if args := strings.TrimSpace(item.Get("arguments").String()); args != "" {
					segments = append(segments, args)
				}
			case "function_call_output":
				if out := strings.TrimSpace(item.Get("output").String()); out != "" {
					segments = append(segments, out)
				}
			default:
				if text := strings.TrimSpace(item.Get("text").String()); text != "" {
					segments = append(segments, text)
				}
			}
		}
	}

	tools := root.Get("tools")
	if tools.IsArray() {
		tarr := tools.Array()
		for i := range tarr {
			tool := tarr[i]
			if name := strings.TrimSpace(tool.Get("name").String()); name != "" {
				segments = append(segments, name)
			}
			if desc := strings.TrimSpace(tool.Get("description").String()); desc != "" {
				segments = append(segments, desc)
			}
			if params := tool.Get("parameters"); params.Exists() {
				val := params.Raw
				if params.Type == gjson.String {
					val = params.String()
				}
				if trimmed := strings.TrimSpace(val); trimmed != "" {
					segments = append(segments, trimmed)
				}
			}
		}
	}

	textFormat := root.Get("text.format")
	if textFormat.Exists() {
		if name := strings.TrimSpace(textFormat.Get("name").String()); name != "" {
			segments = append(segments, name)
		}
		if schema := textFormat.Get("schema"); schema.Exists() {
			val := schema.Raw
			if schema.Type == gjson.String {
				val = schema.String()
			}
			if trimmed := strings.TrimSpace(val); trimmed != "" {
				segments = append(segments, trimmed)
			}
		}
	}

	text := strings.Join(segments, "\n")
	if text == "" {
		return 0, nil
	}

	count, err := enc.Count(text)
	if err != nil {
		return 0, err
	}
	return int64(count), nil
}

func (e *CodexExecutor) Refresh(ctx context.Context, auth *cliproxyauth.Auth) (*cliproxyauth.Auth, error) {
	log.Debugf("codex executor: refresh called")
	if auth == nil {
		return nil, statusErr{code: 500, msg: "codex executor: auth is nil"}
	}
	var refreshToken string
	if auth.Metadata != nil {
		if v, ok := auth.Metadata["refresh_token"].(string); ok && v != "" {
			refreshToken = v
		}
	}
	if refreshToken == "" {
		return auth, nil
	}
	svc := codexauth.NewCodexAuth(e.cfg)
	td, err := svc.RefreshTokensWithRetry(ctx, refreshToken, 3)
	if err != nil {
		return nil, err
	}
	if auth.Metadata == nil {
		auth.Metadata = make(map[string]any)
	}
	auth.Metadata["id_token"] = td.IDToken
	auth.Metadata["access_token"] = td.AccessToken
	if td.RefreshToken != "" {
		auth.Metadata["refresh_token"] = td.RefreshToken
	}
	if td.AccountID != "" {
		auth.Metadata["account_id"] = td.AccountID
	}
	auth.Metadata["email"] = td.Email
	// Use unified key in files
	auth.Metadata["expired"] = td.Expire
	auth.Metadata["type"] = "codex"
	now := time.Now().Format(time.RFC3339)
	auth.Metadata["last_refresh"] = now
	return auth, nil
}

func (e *CodexExecutor) cacheHelper(ctx context.Context, from sdktranslator.Format, url string, req cliproxyexecutor.Request, rawJSON []byte) (*http.Request, error) {
	var cache codexCache
	if from == "claude" {
		userIDResult := gjson.GetBytes(req.Payload, "metadata.user_id")
		if userIDResult.Exists() {
			var hasKey bool
			key := fmt.Sprintf("%s-%s", req.Model, userIDResult.String())
			if cache, hasKey = getCodexCache(key); !hasKey || cache.Expire.Before(time.Now()) {
				cache = codexCache{
					ID:     uuid.New().String(),
					Expire: time.Now().Add(1 * time.Hour),
				}
				setCodexCache(key, cache)
			}
		}
	} else if from == "openai-response" {
		promptCacheKey := gjson.GetBytes(req.Payload, "prompt_cache_key")
		if promptCacheKey.Exists() {
			cache.ID = promptCacheKey.String()
		}
	}

	rawJSON, _ = sjson.SetBytes(rawJSON, "prompt_cache_key", cache.ID)
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(rawJSON))
	if err != nil {
		return nil, err
	}
	httpReq.Header.Set("Conversation_id", cache.ID)
	httpReq.Header.Set("Session_id", cache.ID)
	return httpReq, nil
}

func applyCodexHeaders(r *http.Request, auth *cliproxyauth.Auth, token string) {
	r.Header.Set("Content-Type", "application/json")
	r.Header.Set("Authorization", "Bearer "+token)

	var ginHeaders http.Header
	if ginCtx, ok := r.Context().Value("gin").(*gin.Context); ok && ginCtx != nil && ginCtx.Request != nil {
		ginHeaders = ginCtx.Request.Header
	}

	misc.EnsureHeader(r.Header, ginHeaders, "Version", "0.21.0")
	misc.EnsureHeader(r.Header, ginHeaders, "Openai-Beta", "responses=experimental")
	misc.EnsureHeader(r.Header, ginHeaders, "Session_id", uuid.NewString())
	misc.EnsureHeader(r.Header, ginHeaders, "User-Agent", "codex_cli_rs/0.50.0 (Mac OS 26.0.1; arm64) Apple_Terminal/464")

	r.Header.Set("Accept", "text/event-stream")
	r.Header.Set("Connection", "Keep-Alive")

	isAPIKey := false
	if auth != nil && auth.Attributes != nil {
		if v := strings.TrimSpace(auth.Attributes["api_key"]); v != "" {
			isAPIKey = true
		}
	}
	if !isAPIKey {
		r.Header.Set("Originator", "codex_cli_rs")
		if auth != nil && auth.Metadata != nil {
			if accountID, ok := auth.Metadata["account_id"].(string); ok {
				r.Header.Set("Chatgpt-Account-Id", accountID)
			}
		}
	}
	var attrs map[string]string
	if auth != nil {
		attrs = auth.Attributes
	}
	util.ApplyCustomHeadersFromAttrs(r, attrs)
}

func codexCreds(a *cliproxyauth.Auth) (apiKey, baseURL string) {
	if a == nil {
		return "", ""
	}
	if a.Attributes != nil {
		apiKey = a.Attributes["api_key"]
		baseURL = a.Attributes["base_url"]
	}
	if apiKey == "" && a.Metadata != nil {
		if v, ok := a.Metadata["access_token"].(string); ok {
			apiKey = v
		}
	}
	return
}

func (e *CodexExecutor) resolveUpstreamModel(alias string, auth *cliproxyauth.Auth) string {
	trimmed := strings.TrimSpace(alias)
	if trimmed == "" {
		return ""
	}

	entry := e.resolveCodexConfig(auth)
	if entry == nil {
		return ""
	}

	normalizedModel, metadata := util.NormalizeThinkingModel(trimmed)

	// Candidate names to match against configured aliases/names.
	candidates := []string{strings.TrimSpace(normalizedModel)}
	if !strings.EqualFold(normalizedModel, trimmed) {
		candidates = append(candidates, trimmed)
	}
	if original := util.ResolveOriginalModel(normalizedModel, metadata); original != "" && !strings.EqualFold(original, normalizedModel) {
		candidates = append(candidates, original)
	}

	for i := range entry.Models {
		model := entry.Models[i]
		name := strings.TrimSpace(model.Name)
		modelAlias := strings.TrimSpace(model.Alias)

		for _, candidate := range candidates {
			if candidate == "" {
				continue
			}
			if modelAlias != "" && strings.EqualFold(modelAlias, candidate) {
				if name != "" {
					return name
				}
				return candidate
			}
			if name != "" && strings.EqualFold(name, candidate) {
				return name
			}
		}
	}
	return ""
}

func (e *CodexExecutor) resolveCodexConfig(auth *cliproxyauth.Auth) *config.CodexKey {
	if auth == nil || e.cfg == nil {
		return nil
	}
	var attrKey, attrBase string
	if auth.Attributes != nil {
		attrKey = strings.TrimSpace(auth.Attributes["api_key"])
		attrBase = strings.TrimSpace(auth.Attributes["base_url"])
	}
	for i := range e.cfg.CodexKey {
		entry := &e.cfg.CodexKey[i]
		cfgKey := strings.TrimSpace(entry.APIKey)
		cfgBase := strings.TrimSpace(entry.BaseURL)
		if attrKey != "" && attrBase != "" {
			if strings.EqualFold(cfgKey, attrKey) && strings.EqualFold(cfgBase, attrBase) {
				return entry
			}
			continue
		}
		if attrKey != "" && strings.EqualFold(cfgKey, attrKey) {
			if cfgBase == "" || strings.EqualFold(cfgBase, attrBase) {
				return entry
			}
		}
		if attrKey == "" && attrBase != "" && strings.EqualFold(cfgBase, attrBase) {
			return entry
		}
	}
	if attrKey != "" {
		for i := range e.cfg.CodexKey {
			entry := &e.cfg.CodexKey[i]
			if strings.EqualFold(strings.TrimSpace(entry.APIKey), attrKey) {
				return entry
			}
		}
	}
	return nil
}