package management

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net"
	"net/http"
	"path/filepath"
	"strconv"
	"strings"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
	geminiAuth "github.com/router-for-me/CLIProxyAPI/v6/internal/auth/gemini"
	"github.com/router-for-me/CLIProxyAPI/v6/internal/interfaces"
	sdkAuth "github.com/router-for-me/CLIProxyAPI/v6/sdk/auth"
	coreauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
	log "github.com/sirupsen/logrus"
	"github.com/tidwall/gjson"
)

var lastRefreshKeys = []string{"last_refresh", "lastRefresh", "last_refreshed_at", "lastRefreshedAt"}

const (
	anthropicCallbackPort   = 54545
	geminiCallbackPort      = 8085
	codexCallbackPort       = 1455
	geminiCLIEndpoint       = "https://cloudcode-pa.googleapis.com"
	geminiCLIVersion        = "v1internal"
	geminiCLIUserAgent      = "google-api-nodejs-client/9.15.1"
	geminiCLIApiClient      = "gl-node/22.17.0"
	geminiCLIClientMetadata = "ideType=IDE_UNSPECIFIED,platform=PLATFORM_UNSPECIFIED,pluginType=GEMINI"
)

type callbackForwarder struct {
	provider string
	server   *http.Server
	done     chan struct{}
}

var (
	callbackForwardersMu sync.Mutex
	callbackForwarders   = make(map[int]*callbackForwarder)
)

func extractLastRefreshTimestamp(meta map[string]any) (time.Time, bool) {
	if len(meta) == 0 {
		return time.Time{}, false
	}
	for _, key := range lastRefreshKeys {
		if val, ok := meta[key]; ok {
			if ts, ok1 := parseLastRefreshValue(val); ok1 {
				return ts, true
			}
		}
	}
	return time.Time{}, false
}

func parseLastRefreshValue(v any) (time.Time, bool) {
	switch val := v.(type) {
	case string:
		s := strings.TrimSpace(val)
		if s == "" {
			return time.Time{}, false
		}
		layouts := []string{time.RFC3339, time.RFC3339Nano, "2006-01-02 15:04:05", "2006-01-02T15:04:05Z07:00"}
		for _, layout := range layouts {
			if ts, err := time.Parse(layout, s); err == nil {
				return ts.UTC(), true
			}
		}
		if unix, err := strconv.ParseInt(s, 10, 64); err == nil && unix > 0 {
			return time.Unix(unix, 0).UTC(), true
		}
	case float64:
		if val <= 0 {
			return time.Time{}, false
		}
		return time.Unix(int64(val), 0).UTC(), true
	case int64:
		if val <= 0 {
			return time.Time{}, false
		}
		return time.Unix(val, 0).UTC(), true
	case int:
		if val <= 0 {
			return time.Time{}, false
		}
		return time.Unix(int64(val), 0).UTC(), true
	case json.Number:
		if i, err := val.Int64(); err == nil && i > 0 {
			return time.Unix(i, 0).UTC(), true
		}
	}
	return time.Time{}, false
}

func isWebUIRequest(c *gin.Context) bool {
	raw := strings.TrimSpace(c.Query("is_webui"))
	if raw == "" {
		return false
	}
	switch strings.ToLower(raw) {
	case "1", "true", "yes", "on":
		return true
	default:
		return false
	}
}

func startCallbackForwarder(port int, provider, targetBase string) (*callbackForwarder, error) {
	callbackForwardersMu.Lock()
	prev := callbackForwarders[port]
	if prev != nil {
		delete(callbackForwarders, port)
	}
	callbackForwardersMu.Unlock()

	if prev != nil {
		stopForwarderInstance(port, prev)
	}

	addr := fmt.Sprintf("127.0.0.1:%d", port)
	ln, err := net.Listen("tcp", addr)
	if err != nil {
		return nil, fmt.Errorf("failed to listen on %s: %w", addr, err)
	}

	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		target := targetBase
		if raw := r.URL.RawQuery; raw != "" {
			if strings.Contains(target, "?") {
				target = target + "&" + raw
			} else {
				target = target + "?" + raw
			}
		}
		w.Header().Set("Cache-Control", "no-store")
		http.Redirect(w, r, target, http.StatusFound)
	})

	srv := &http.Server{
		Handler:           handler,
		ReadHeaderTimeout: 5 * time.Second,
		WriteTimeout:      5 * time.Second,
	}
	done := make(chan struct{})

	go func() {
		if errServe := srv.Serve(ln); errServe != nil && !errors.Is(errServe, http.ErrServerClosed) {
			log.WithError(errServe).Warnf("callback forwarder for %s stopped unexpectedly", provider)
		}
		close(done)
	}()

	forwarder := &callbackForwarder{
		provider: provider,
		server:   srv,
		done:     done,
	}

	callbackForwardersMu.Lock()
	callbackForwarders[port] = forwarder
	callbackForwardersMu.Unlock()

	log.Infof("callback forwarder for %s listening on %s", provider, addr)

	return forwarder, nil
}

func stopCallbackForwarder(port int) {
	callbackForwardersMu.Lock()
	forwarder := callbackForwarders[port]
	if forwarder != nil {
		delete(callbackForwarders, port)
	}
	callbackForwardersMu.Unlock()

	stopForwarderInstance(port, forwarder)
}

func stopCallbackForwarderInstance(port int, forwarder *callbackForwarder) {
	if forwarder == nil {
		return
	}
	callbackForwardersMu.Lock()
	if current := callbackForwarders[port]; current == forwarder {
		delete(callbackForwarders, port)
	}
	callbackForwardersMu.Unlock()

	stopForwarderInstance(port, forwarder)
}

func stopForwarderInstance(port int, forwarder *callbackForwarder) {
	if forwarder == nil || forwarder.server == nil {
		return
	}

	ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
	defer cancel()

	if err := forwarder.server.Shutdown(ctx); err != nil && !errors.Is(err, http.ErrServerClosed) {
		log.WithError(err).Warnf("failed to shut down callback forwarder on port %d", port)
	}

	select {
	case <-forwarder.done:
	case <-time.After(2 * time.Second):
	}

	log.Infof("callback forwarder on port %d stopped", port)
}

func (h *Handler) managementCallbackURL(path string) (string, error) {
	if h == nil || h.cfg == nil || h.cfg.Port <= 0 {
		return "", fmt.Errorf("server port is not configured")
	}
	if !strings.HasPrefix(path, "/") {
		path = "/" + path
	}
	scheme := "http"
	if h.cfg.TLS.Enable {
		scheme = "https"
	}
	return fmt.Sprintf("%s://127.0.0.1:%d%s", scheme, h.cfg.Port, path), nil
}

func authEmail(auth *coreauth.Auth) string {
	if auth == nil {
		return ""
	}
	if auth.Metadata != nil {
		if v, ok := auth.Metadata["email"].(string); ok {
			return strings.TrimSpace(v)
		}
	}
	if auth.Attributes != nil {
		if v := strings.TrimSpace(auth.Attributes["email"]); v != "" {
			return v
		}
		if v := strings.TrimSpace(auth.Attributes["account_email"]); v != "" {
			return v
		}
	}
	return ""
}

func authAttribute(auth *coreauth.Auth, key string) string {
	if auth == nil || len(auth.Attributes) == 0 {
		return ""
	}
	return auth.Attributes[key]
}

func isRuntimeOnlyAuth(auth *coreauth.Auth) bool {
	if auth == nil || len(auth.Attributes) == 0 {
		return false
	}
	return strings.EqualFold(strings.TrimSpace(auth.Attributes["runtime_only"]), "true")
}

// Download single auth file by name
func (h *Handler) authIDForPath(path string) string {
	path = strings.TrimSpace(path)
	if path == "" {
		return ""
	}
	if h == nil || h.cfg == nil {
		return path
	}
	authDir := strings.TrimSpace(h.cfg.AuthDir)
	if authDir == "" {
		return path
	}
	if rel, err := filepath.Rel(authDir, path); err == nil && rel != "" {
		return rel
	}
	return path
}

func (h *Handler) deleteTokenRecord(ctx context.Context, path string) error {
	if strings.TrimSpace(path) == "" {
		return fmt.Errorf("auth path is empty")
	}
	store := h.tokenStoreWithBaseDir()
	if store == nil {
		return fmt.Errorf("token store unavailable")
	}
	return store.Delete(ctx, path)
}

func (h *Handler) tokenStoreWithBaseDir() coreauth.Store {
	if h == nil {
		return nil
	}
	store := h.tokenStore
	if store == nil {
		store = sdkAuth.GetTokenStore()
		h.tokenStore = store
	}
	if h.cfg != nil {
		if dirSetter, ok := store.(interface{ SetBaseDir(string) }); ok {
			dirSetter.SetBaseDir(h.cfg.AuthDir)
		}
	}
	return store
}

func (h *Handler) saveTokenRecord(ctx context.Context, record *coreauth.Auth) (string, error) {
	if record == nil {
		return "", fmt.Errorf("token record is nil")
	}
	store := h.tokenStoreWithBaseDir()
	if store == nil {
		return "", fmt.Errorf("token store unavailable")
	}
	return store.Save(ctx, record)
}

func (e *projectSelectionRequiredError) Error() string {
	return "gemini cli: project selection required"
}

func ensureGeminiProjectAndOnboard(ctx context.Context, httpClient *http.Client, storage *geminiAuth.GeminiTokenStorage, requestedProject string) error {
	if storage == nil {
		return fmt.Errorf("gemini storage is nil")
	}

	trimmedRequest := strings.TrimSpace(requestedProject)
	if trimmedRequest == "" {
		projects, errProjects := fetchGCPProjects(ctx, httpClient)
		if errProjects != nil {
			return fmt.Errorf("fetch project list: %w", errProjects)
		}
		if len(projects) == 0 {
			return fmt.Errorf("no Google Cloud projects available for this account")
		}
		trimmedRequest = strings.TrimSpace(projects[0].ProjectID)
		if trimmedRequest == "" {
			return fmt.Errorf("resolved project id is empty")
		}
		storage.Auto = true
	} else {
		storage.Auto = false
	}

	if err := performGeminiCLISetup(ctx, httpClient, storage, trimmedRequest); err != nil {
		return err
	}

	if strings.TrimSpace(storage.ProjectID) == "" {
		storage.ProjectID = trimmedRequest
	}

	return nil
}

func onboardAllGeminiProjects(ctx context.Context, httpClient *http.Client, storage *geminiAuth.GeminiTokenStorage) ([]string, error) {
	projects, errProjects := fetchGCPProjects(ctx, httpClient)
	if errProjects != nil {
		return nil, fmt.Errorf("fetch project list: %w", errProjects)
	}
	if len(projects) == 0 {
		return nil, fmt.Errorf("no Google Cloud projects available for this account")
	}
	activated := make([]string, 0, len(projects))
	seen := make(map[string]struct{}, len(projects))
	for _, project := range projects {
		candidate := strings.TrimSpace(project.ProjectID)
		if candidate == "" {
			continue
		}
		if _, dup := seen[candidate]; dup {
			continue
		}
		if err := performGeminiCLISetup(ctx, httpClient, storage, candidate); err != nil {
			return nil, fmt.Errorf("onboard project %s: %w", candidate, err)
		}
		finalID := strings.TrimSpace(storage.ProjectID)
		if finalID == "" {
			finalID = candidate
		}
		activated = append(activated, finalID)
		seen[candidate] = struct{}{}
	}
	if len(activated) == 0 {
		return nil, fmt.Errorf("no Google Cloud projects available for this account")
	}
	return activated, nil
}

func ensureGeminiProjectsEnabled(ctx context.Context, httpClient *http.Client, projectIDs []string) error {
	for _, pid := range projectIDs {
		trimmed := strings.TrimSpace(pid)
		if trimmed == "" {
			continue
		}
		isChecked, errCheck := checkCloudAPIIsEnabled(ctx, httpClient, trimmed)
		if errCheck != nil {
			return fmt.Errorf("project %s: %w", trimmed, errCheck)
		}
		if !isChecked {
			return fmt.Errorf("project %s: Cloud AI API not enabled", trimmed)
		}
	}
	return nil
}

func performGeminiCLISetup(ctx context.Context, httpClient *http.Client, storage *geminiAuth.GeminiTokenStorage, requestedProject string) error {
	metadata := map[string]string{
		"ideType":    "IDE_UNSPECIFIED",
		"platform":   "PLATFORM_UNSPECIFIED",
		"pluginType": "GEMINI",
	}

	trimmedRequest := strings.TrimSpace(requestedProject)
	explicitProject := trimmedRequest != ""

	loadReqBody := map[string]any{
		"metadata": metadata,
	}
	if explicitProject {
		loadReqBody["cloudaicompanionProject"] = trimmedRequest
	}

	var loadResp map[string]any
	if errLoad := callGeminiCLI(ctx, httpClient, "loadCodeAssist", loadReqBody, &loadResp); errLoad != nil {
		return fmt.Errorf("load code assist: %w", errLoad)
	}

	tierID := "legacy-tier"
	if tiers, okTiers := loadResp["allowedTiers"].([]any); okTiers {
		for _, rawTier := range tiers {
			tier, okTier := rawTier.(map[string]any)
			if !okTier {
				continue
			}
			if isDefault, okDefault := tier["isDefault"].(bool); okDefault && isDefault {
				if id, okID := tier["id"].(string); okID && strings.TrimSpace(id) != "" {
					tierID = strings.TrimSpace(id)
					break
				}
			}
		}
	}

	projectID := trimmedRequest
	if projectID == "" {
		if id, okProject := loadResp["cloudaicompanionProject"].(string); okProject {
			projectID = strings.TrimSpace(id)
		}
		if projectID == "" {
			if projectMap, okProject := loadResp["cloudaicompanionProject"].(map[string]any); okProject {
				if id, okID := projectMap["id"].(string); okID {
					projectID = strings.TrimSpace(id)
				}
			}
		}
	}
	if projectID == "" {
		return &projectSelectionRequiredError{}
	}

	onboardReqBody := map[string]any{
		"tierId":                  tierID,
		"metadata":                metadata,
		"cloudaicompanionProject": projectID,
	}

	storage.ProjectID = projectID

	for {
		var onboardResp map[string]any
		if errOnboard := callGeminiCLI(ctx, httpClient, "onboardUser", onboardReqBody, &onboardResp); errOnboard != nil {
			return fmt.Errorf("onboard user: %w", errOnboard)
		}

		if done, okDone := onboardResp["done"].(bool); okDone && done {
			responseProjectID := ""
			if resp, okResp := onboardResp["response"].(map[string]any); okResp {
				switch projectValue := resp["cloudaicompanionProject"].(type) {
				case map[string]any:
					if id, okID := projectValue["id"].(string); okID {
						responseProjectID = strings.TrimSpace(id)
					}
				case string:
					responseProjectID = strings.TrimSpace(projectValue)
				}
			}

			finalProjectID := projectID
			if responseProjectID != "" {
				if explicitProject && !strings.EqualFold(responseProjectID, projectID) {
					// Check if this is a free user (gen-lang-client projects or free/legacy tier)
					isFreeUser := strings.HasPrefix(projectID, "gen-lang-client-") ||
						strings.EqualFold(tierID, "FREE") ||
						strings.EqualFold(tierID, "LEGACY")

					if isFreeUser {
						// For free users, use backend project ID for preview model access
						log.Infof("Gemini onboarding: frontend project %s maps to backend project %s", projectID, responseProjectID)
						log.Infof("Using backend project ID: %s (recommended for preview model access)", responseProjectID)
						finalProjectID = responseProjectID
					} else {
						// Pro users: keep requested project ID (original behavior)
						log.Warnf("Gemini onboarding returned project %s instead of requested %s; keeping requested project ID.", responseProjectID, projectID)
					}
				} else {
					finalProjectID = responseProjectID
				}
			}

			storage.ProjectID = strings.TrimSpace(finalProjectID)
			if storage.ProjectID == "" {
				storage.ProjectID = strings.TrimSpace(projectID)
			}
			if storage.ProjectID == "" {
				return fmt.Errorf("onboard user completed without project id")
			}
			log.Infof("Onboarding complete. Using Project ID: %s", storage.ProjectID)
			return nil
		}

		log.Println("Onboarding in progress, waiting 5 seconds...")
		time.Sleep(5 * time.Second)
	}
}

func callGeminiCLI(ctx context.Context, httpClient *http.Client, endpoint string, body any, result any) error {
	endPointURL := fmt.Sprintf("%s/%s:%s", geminiCLIEndpoint, geminiCLIVersion, endpoint)
	if strings.HasPrefix(endpoint, "operations/") {
		endPointURL = fmt.Sprintf("%s/%s", geminiCLIEndpoint, endpoint)
	}

	var reader io.Reader
	if body != nil {
		rawBody, errMarshal := json.Marshal(body)
		if errMarshal != nil {
			return fmt.Errorf("marshal request body: %w", errMarshal)
		}
		reader = bytes.NewReader(rawBody)
	}

	req, errRequest := http.NewRequestWithContext(ctx, http.MethodPost, endPointURL, reader)
	if errRequest != nil {
		return fmt.Errorf("create request: %w", errRequest)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("User-Agent", geminiCLIUserAgent)
	req.Header.Set("X-Goog-Api-Client", geminiCLIApiClient)
	req.Header.Set("Client-Metadata", geminiCLIClientMetadata)

	resp, errDo := httpClient.Do(req)
	if errDo != nil {
		return fmt.Errorf("execute request: %w", errDo)
	}
	defer func() {
		if errClose := resp.Body.Close(); errClose != nil {
			log.Errorf("response body close error: %v", errClose)
		}
	}()

	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("api request failed with status %d: %s", resp.StatusCode, strings.TrimSpace(string(bodyBytes)))
	}

	if result == nil {
		_, _ = io.Copy(io.Discard, resp.Body)
		return nil
	}

	if errDecode := json.NewDecoder(resp.Body).Decode(result); errDecode != nil {
		return fmt.Errorf("decode response body: %w", errDecode)
	}

	return nil
}

func fetchGCPProjects(ctx context.Context, httpClient *http.Client) ([]interfaces.GCPProjectProjects, error) {
	req, errRequest := http.NewRequestWithContext(ctx, http.MethodGet, "https://cloudresourcemanager.googleapis.com/v1/projects", http.NoBody)
	if errRequest != nil {
		return nil, fmt.Errorf("could not create project list request: %w", errRequest)
	}

	resp, errDo := httpClient.Do(req)
	if errDo != nil {
		return nil, fmt.Errorf("failed to execute project list request: %w", errDo)
	}
	defer func() {
		if errClose := resp.Body.Close(); errClose != nil {
			log.Errorf("response body close error: %v", errClose)
		}
	}()

	if resp.StatusCode < http.StatusOK || resp.StatusCode >= http.StatusMultipleChoices {
		bodyBytes, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("project list request failed with status %d: %s", resp.StatusCode, strings.TrimSpace(string(bodyBytes)))
	}

	var projects interfaces.GCPProject
	if errDecode := json.NewDecoder(resp.Body).Decode(&projects); errDecode != nil {
		return nil, fmt.Errorf("failed to unmarshal project list: %w", errDecode)
	}

	return projects.Projects, nil
}

func checkCloudAPIIsEnabled(ctx context.Context, httpClient *http.Client, projectID string) (bool, error) {
	serviceUsageURL := "https://serviceusage.googleapis.com"
	requiredServices := []string{
		"cloudaicompanion.googleapis.com",
	}
	for _, service := range requiredServices {
		checkURL := fmt.Sprintf("%s/v1/projects/%s/services/%s", serviceUsageURL, projectID, service)
		req, errRequest := http.NewRequestWithContext(ctx, http.MethodGet, checkURL, http.NoBody)
		if errRequest != nil {
			return false, fmt.Errorf("failed to create request: %w", errRequest)
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("User-Agent", geminiCLIUserAgent)
		resp, errDo := httpClient.Do(req)
		if errDo != nil {
			return false, fmt.Errorf("failed to execute request: %w", errDo)
		}

		if resp.StatusCode == http.StatusOK {
			bodyBytes, _ := io.ReadAll(resp.Body)
			if gjson.GetBytes(bodyBytes, "state").String() == "ENABLED" {
				_ = resp.Body.Close()
				continue
			}
		}
		_ = resp.Body.Close()

		enableURL := fmt.Sprintf("%s/v1/projects/%s/services/%s:enable", serviceUsageURL, projectID, service)
		req, errRequest = http.NewRequestWithContext(ctx, http.MethodPost, enableURL, strings.NewReader("{}"))
		if errRequest != nil {
			return false, fmt.Errorf("failed to create request: %w", errRequest)
		}
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("User-Agent", geminiCLIUserAgent)
		resp, errDo = httpClient.Do(req)
		if errDo != nil {
			return false, fmt.Errorf("failed to execute request: %w", errDo)
		}

		bodyBytes, _ := io.ReadAll(resp.Body)
		errMessage := string(bodyBytes)
		errMessageResult := gjson.GetBytes(bodyBytes, "error.message")
		if errMessageResult.Exists() {
			errMessage = errMessageResult.String()
		}
		if resp.StatusCode == http.StatusOK || resp.StatusCode == http.StatusCreated {
			_ = resp.Body.Close()
			continue
		} else if resp.StatusCode == http.StatusBadRequest {
			_ = resp.Body.Close()
			if strings.Contains(strings.ToLower(errMessage), "already enabled") {
				continue
			}
		}
		_ = resp.Body.Close()
		return false, fmt.Errorf("project activation required: %s", errMessage)
	}
	return true, nil
}