package management

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"mime/multipart"
	"net/http"
	"os"
	"path/filepath"
	"runtime"
	"sort"
	"strings"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/router-for-me/CLIProxyAPI/v7/internal/util"
	"github.com/router-for-me/CLIProxyAPI/v7/internal/watcher/synthesizer"
	coreauth "github.com/router-for-me/CLIProxyAPI/v7/sdk/cliproxy/auth"
)

// Download single auth file by name
func (h *Handler) DownloadAuthFile(c *gin.Context) {
	name := strings.TrimSpace(c.Query("name"))
	if isUnsafeAuthFileName(name) {
		c.JSON(400, gin.H{"error": "invalid name"})
		return
	}
	if !strings.HasSuffix(strings.ToLower(name), ".json") {
		c.JSON(400, gin.H{"error": "name must end with .json"})
		return
	}
	full := filepath.Join(h.cfg.AuthDir, name)
	data, err := os.ReadFile(full)
	if err != nil {
		if os.IsNotExist(err) {
			c.JSON(404, gin.H{"error": "file not found"})
		} else {
			c.JSON(500, gin.H{"error": fmt.Sprintf("failed to read file: %v", err)})
		}
		return
	}
	c.Header("Content-Disposition", fmt.Sprintf("attachment; filename=\"%s\"", name))
	c.Data(200, "application/json", data)
}

// Upload auth file: multipart or raw JSON with ?name=
func (h *Handler) UploadAuthFile(c *gin.Context) {
	if h.authManager == nil {
		c.JSON(http.StatusServiceUnavailable, gin.H{"error": "core auth manager unavailable"})
		return
	}
	ctx := c.Request.Context()

	fileHeaders, errMultipart := h.multipartAuthFileHeaders(c)
	if errMultipart != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("invalid multipart form: %v", errMultipart)})
		return
	}
	if len(fileHeaders) == 1 {
		if _, errUpload := h.storeUploadedAuthFile(ctx, fileHeaders[0]); errUpload != nil {
			if errors.Is(errUpload, errAuthFileMustBeJSON) {
				c.JSON(http.StatusBadRequest, gin.H{"error": "file must be .json"})
				return
			}
			c.JSON(http.StatusInternalServerError, gin.H{"error": errUpload.Error()})
			return
		}
		c.JSON(http.StatusOK, gin.H{"status": "ok"})
		return
	}
	if len(fileHeaders) > 1 {
		uploaded := make([]string, 0, len(fileHeaders))
		failed := make([]gin.H, 0)
		for _, file := range fileHeaders {
			name, errUpload := h.storeUploadedAuthFile(ctx, file)
			if errUpload != nil {
				failureName := ""
				if file != nil {
					failureName = filepath.Base(file.Filename)
				}
				msg := errUpload.Error()
				if errors.Is(errUpload, errAuthFileMustBeJSON) {
					msg = "file must be .json"
				}
				failed = append(failed, gin.H{"name": failureName, "error": msg})
				continue
			}
			uploaded = append(uploaded, name)
		}
		if len(failed) > 0 {
			c.JSON(http.StatusMultiStatus, gin.H{
				"status":   "partial",
				"uploaded": len(uploaded),
				"files":    uploaded,
				"failed":   failed,
			})
			return
		}
		c.JSON(http.StatusOK, gin.H{"status": "ok", "uploaded": len(uploaded), "files": uploaded})
		return
	}
	if c.ContentType() == "multipart/form-data" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "no files uploaded"})
		return
	}
	name := strings.TrimSpace(c.Query("name"))
	if isUnsafeAuthFileName(name) {
		c.JSON(400, gin.H{"error": "invalid name"})
		return
	}
	if !strings.HasSuffix(strings.ToLower(name), ".json") {
		c.JSON(400, gin.H{"error": "name must end with .json"})
		return
	}
	data, err := io.ReadAll(c.Request.Body)
	if err != nil {
		c.JSON(400, gin.H{"error": "failed to read body"})
		return
	}
	if err = h.writeAuthFile(ctx, filepath.Base(name), data); err != nil {
		c.JSON(500, gin.H{"error": err.Error()})
		return
	}
	c.JSON(200, gin.H{"status": "ok"})
}

// Delete auth files: single by name or all
func (h *Handler) DeleteAuthFile(c *gin.Context) {
	if h.authManager == nil {
		c.JSON(http.StatusServiceUnavailable, gin.H{"error": "core auth manager unavailable"})
		return
	}
	ctx := c.Request.Context()
	names, errNames := requestedAuthFileNamesForDelete(c)
	if errNames != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": errNames.Error()})
		return
	}
	if len(names) == 0 {
		c.JSON(400, gin.H{"error": "invalid name"})
		return
	}
	if len(names) != 1 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "exactly one account is required"})
		return
	}
	if _, status, errDelete := h.deleteAuthFileByName(ctx, names[0]); errDelete != nil {
		c.JSON(status, gin.H{"error": errDelete.Error()})
		return
	}
	c.JSON(http.StatusOK, gin.H{"status": "ok"})
}

func (h *Handler) multipartAuthFileHeaders(c *gin.Context) ([]*multipart.FileHeader, error) {
	if h == nil || c == nil || c.ContentType() != "multipart/form-data" {
		return nil, nil
	}
	form, err := c.MultipartForm()
	if err != nil {
		return nil, err
	}
	if form == nil || len(form.File) == 0 {
		return nil, nil
	}

	keys := make([]string, 0, len(form.File))
	for key := range form.File {
		keys = append(keys, key)
	}
	sort.Strings(keys)

	headers := make([]*multipart.FileHeader, 0)
	for _, key := range keys {
		headers = append(headers, form.File[key]...)
	}
	return headers, nil
}

func (h *Handler) storeUploadedAuthFile(ctx context.Context, file *multipart.FileHeader) (string, error) {
	if file == nil {
		return "", fmt.Errorf("no file uploaded")
	}
	name := filepath.Base(strings.TrimSpace(file.Filename))
	if !strings.HasSuffix(strings.ToLower(name), ".json") {
		return "", errAuthFileMustBeJSON
	}
	src, err := file.Open()
	if err != nil {
		return "", fmt.Errorf("failed to open uploaded file: %w", err)
	}
	defer src.Close()

	data, err := io.ReadAll(src)
	if err != nil {
		return "", fmt.Errorf("failed to read uploaded file: %w", err)
	}
	if err := h.writeAuthFile(ctx, name, data); err != nil {
		return "", err
	}
	return name, nil
}

func (h *Handler) writeAuthFile(ctx context.Context, name string, data []byte) error {
	dst := filepath.Join(h.cfg.AuthDir, filepath.Base(name))
	if !filepath.IsAbs(dst) {
		if abs, errAbs := filepath.Abs(dst); errAbs == nil {
			dst = abs
		}
	}
	auth, err := h.buildAuthFromFileData(dst, data)
	if err != nil {
		return err
	}
	if errWrite := os.WriteFile(dst, data, 0o600); errWrite != nil {
		return fmt.Errorf("failed to write file: %w", errWrite)
	}
	if err := h.upsertAuthRecord(ctx, auth); err != nil {
		return err
	}
	return nil
}

func requestedAuthFileNamesForDelete(c *gin.Context) ([]string, error) {
	if c == nil {
		return nil, nil
	}
	names := uniqueAuthFileNames(c.QueryArray("name"))
	if len(names) > 0 {
		return names, nil
	}

	body, err := io.ReadAll(c.Request.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read body")
	}
	body = bytes.TrimSpace(body)
	if len(body) == 0 {
		return nil, nil
	}

	var objectBody struct {
		Name  string   `json:"name"`
		Names []string `json:"names"`
	}
	if body[0] == '[' {
		var arrayBody []string
		if err := json.Unmarshal(body, &arrayBody); err != nil {
			return nil, fmt.Errorf("invalid request body")
		}
		return uniqueAuthFileNames(arrayBody), nil
	}
	if err := json.Unmarshal(body, &objectBody); err != nil {
		return nil, fmt.Errorf("invalid request body")
	}

	out := make([]string, 0, len(objectBody.Names)+1)
	if strings.TrimSpace(objectBody.Name) != "" {
		out = append(out, objectBody.Name)
	}
	out = append(out, objectBody.Names...)
	return uniqueAuthFileNames(out), nil
}

func uniqueAuthFileNames(names []string) []string {
	if len(names) == 0 {
		return nil
	}
	seen := make(map[string]struct{}, len(names))
	out := make([]string, 0, len(names))
	for _, name := range names {
		name = strings.TrimSpace(name)
		if name == "" {
			continue
		}
		if _, ok := seen[name]; ok {
			continue
		}
		seen[name] = struct{}{}
		out = append(out, name)
	}
	return out
}

func (h *Handler) deleteAuthFileByName(ctx context.Context, name string) (string, int, error) {
	name = strings.TrimSpace(name)
	if isUnsafeAuthFileName(name) {
		return "", http.StatusBadRequest, fmt.Errorf("invalid name")
	}

	targetPath := filepath.Join(h.cfg.AuthDir, filepath.Base(name))
	targetID := ""
	targetAuth := h.findAuthForDelete(name)
	if targetAuth == nil || !strings.EqualFold(strings.TrimSpace(targetAuth.Provider), "codex") || targetAuth.AuthKind() != "oauth" {
		return filepath.Base(name), http.StatusNotFound, errAuthFileNotFound
	}
	if targetAuth != nil {
		if !isPluginVirtualSourceDelete(name, targetAuth) {
			return filepath.Base(name), http.StatusConflict, errPluginVirtualAuth
		}
		targetID = strings.TrimSpace(targetAuth.ID)
		if path := strings.TrimSpace(authAttribute(targetAuth, "path")); path != "" {
			targetPath = path
		}
	}
	if !filepath.IsAbs(targetPath) {
		if abs, errAbs := filepath.Abs(targetPath); errAbs == nil {
			targetPath = abs
		}
	}
	if errRemove := os.Remove(targetPath); errRemove != nil {
		if os.IsNotExist(errRemove) {
			return filepath.Base(name), http.StatusNotFound, errAuthFileNotFound
		}
		return filepath.Base(name), http.StatusInternalServerError, fmt.Errorf("failed to remove file: %w", errRemove)
	}
	if errDeleteRecord := h.deleteTokenRecord(ctx, targetPath); errDeleteRecord != nil {
		return filepath.Base(name), http.StatusInternalServerError, errDeleteRecord
	}
	h.removeAuthsForPath(ctx, targetPath, targetID)
	return filepath.Base(name), http.StatusOK, nil
}

func isPluginVirtualSourceDelete(name string, auth *coreauth.Auth) bool {
	if !coreauth.IsPluginVirtualAuth(auth) {
		return true
	}
	sourcePath := strings.TrimSpace(authAttribute(auth, coreauth.AttributeVirtualSource))
	if sourcePath == "" {
		sourcePath = strings.TrimSpace(authAttribute(auth, "path"))
	}
	if sourcePath == "" {
		return false
	}
	return strings.EqualFold(filepath.Base(strings.TrimSpace(name)), filepath.Base(sourcePath))
}

func (h *Handler) findAuthForDelete(name string) *coreauth.Auth {
	if h == nil || h.authManager == nil {
		return nil
	}
	name = strings.TrimSpace(name)
	if name == "" {
		return nil
	}
	if auth, ok := h.authManager.GetByID(name); ok {
		return auth
	}
	auths := h.authManager.List()
	for _, auth := range auths {
		if auth == nil {
			continue
		}
		if strings.TrimSpace(auth.FileName) == name {
			return auth
		}
		if filepath.Base(strings.TrimSpace(authAttribute(auth, "path"))) == name {
			return auth
		}
	}
	return nil
}

func (h *Handler) authIDForPath(path string) string {
	path = strings.TrimSpace(path)
	if path == "" {
		return ""
	}
	path = filepath.Clean(path)
	if !filepath.IsAbs(path) {
		if abs, errAbs := filepath.Abs(path); errAbs == nil {
			path = abs
		}
	}
	id := path
	if h != nil && h.cfg != nil {
		authDir := strings.TrimSpace(h.cfg.AuthDir)
		if resolvedAuthDir, errResolve := util.ResolveAuthDir(authDir); errResolve == nil && resolvedAuthDir != "" {
			authDir = resolvedAuthDir
		}
		if authDir != "" {
			authDir = filepath.Clean(authDir)
			if !filepath.IsAbs(authDir) {
				if abs, errAbs := filepath.Abs(authDir); errAbs == nil {
					authDir = abs
				}
			}
			if rel, errRel := filepath.Rel(authDir, path); errRel == nil && rel != "" {
				id = rel
			}
		}
	}
	// On Windows, normalize ID casing to avoid duplicate auth entries caused by case-insensitive paths.
	if runtime.GOOS == "windows" {
		id = strings.ToLower(id)
	}
	return id
}

func (h *Handler) registerAuthFromFile(ctx context.Context, path string, data []byte) error {
	if h.authManager == nil {
		return nil
	}
	auth, err := h.buildAuthFromFileData(path, data)
	if err != nil {
		return err
	}
	return h.upsertAuthRecord(ctx, auth)
}

func (h *Handler) buildAuthFromFileData(path string, data []byte) (*coreauth.Auth, error) {
	if path == "" {
		return nil, fmt.Errorf("auth path is empty")
	}
	if data == nil {
		var err error
		data, err = os.ReadFile(path)
		if err != nil {
			return nil, fmt.Errorf("failed to read auth file: %w", err)
		}
	}
	metadata := make(map[string]any)
	if err := json.Unmarshal(data, &metadata); err != nil {
		return nil, fmt.Errorf("invalid auth file: %w", err)
	}
	coreauth.NormalizeCredentialMetadata(metadata)
	provider, _ := metadata["type"].(string)
	if provider == "" {
		provider = "unknown"
	}
	label := provider
	if email, ok := metadata["email"].(string); ok && email != "" {
		label = email
	}
	lastRefresh, hasLastRefresh := extractLastRefreshTimestamp(metadata)

	authID := h.authIDForPath(path)
	if authID == "" {
		authID = path
	}
	auth := (*coreauth.Auth)(nil)
	if h != nil && h.cfg != nil {
		sctx := &synthesizer.SynthesisContext{
			Config:      h.cfg,
			AuthDir:     h.cfg.AuthDir,
			Now:         time.Now(),
			IDGenerator: synthesizer.NewStableIDGenerator(),
		}
		generated, errSynthesize := synthesizer.SynthesizeAuthFile(sctx, path, data)
		if errSynthesize != nil {
			return nil, fmt.Errorf("invalid auth file: %w", errSynthesize)
		}
		if len(generated) > 0 && generated[0] != nil {
			auth = generated[0].Clone()
		}
	}
	if auth == nil {
		auth = &coreauth.Auth{
			ID:       authID,
			Provider: provider,
			Label:    label,
			Status:   coreauth.StatusActive,
			Attributes: map[string]string{
				"path":   path,
				"source": path,
			},
			Metadata:  metadata,
			CreatedAt: time.Now(),
			UpdatedAt: time.Now(),
		}
	}
	auth.ID = authID
	auth.FileName = filepath.Base(path)
	if hasLastRefresh {
		auth.LastRefreshedAt = lastRefresh
	}
	if h != nil && h.authManager != nil {
		if existing, ok := h.authManager.GetByID(authID); ok {
			auth.CreatedAt = existing.CreatedAt
			if !hasLastRefresh {
				auth.LastRefreshedAt = existing.LastRefreshedAt
			}
			auth.NextRefreshAfter = existing.NextRefreshAfter
			auth.Runtime = existing.Runtime
		}
	}
	coreauth.ApplyCustomHeadersFromMetadata(auth)
	return auth, nil
}

func (h *Handler) upsertAuthRecord(ctx context.Context, auth *coreauth.Auth) error {
	if h == nil || h.authManager == nil || auth == nil {
		return nil
	}
	if existing, ok := h.authManager.GetByID(auth.ID); ok {
		auth.CreatedAt = existing.CreatedAt
		_, err := h.authManager.Update(ctx, auth)
		return err
	}
	_, err := h.authManager.Register(ctx, auth)
	return err
}