package v0

import (
	"context"
	"encoding/json"
	"errors"
	"net/http"
	"strings"

	"github.com/danielgtaylor/huma/v2"
	"github.com/modelcontextprotocol/registry/internal/auth"
	"github.com/modelcontextprotocol/registry/internal/config"
	"github.com/modelcontextprotocol/registry/internal/database"
	"github.com/modelcontextprotocol/registry/internal/model"
	"github.com/modelcontextprotocol/registry/internal/service"
	"github.com/modelcontextprotocol/registry/internal/validators"
)

// EditServerInput represents the input for editing a server
type EditServerInput struct {
	Authorization string `header:"Authorization" doc:"Registry JWT token with edit permissions" required:"true"`
	ID            string `path:"id" doc:"Server ID (UUID)" format:"uuid"`
	RawBody       []byte `body:"raw"`
}

// RegisterEditEndpoints registers the edit endpoint
func RegisterEditEndpoints(api huma.API, registry service.RegistryService, cfg *config.Config) {
	jwtManager := auth.NewJWTManager(cfg)

	// Edit server endpoint
	huma.Register(api, huma.Operation{
		OperationID: "edit-server",
		Method:      http.MethodPut,
		Path:        "/v0/servers/{id}",
		Summary:     "Edit MCP server",
		Description: "Update an existing MCP server (admin only)",
		Tags:        []string{"admin"},
		Security: []map[string][]string{
			{"bearer": {}},
		},
	}, func(ctx context.Context, input *EditServerInput) (*Response[model.ServerResponse], error) {
		// Extract bearer token
		const bearerPrefix = "Bearer "
		authHeader := input.Authorization
		if len(authHeader) < len(bearerPrefix) || !strings.EqualFold(authHeader[:len(bearerPrefix)], bearerPrefix) {
			return nil, huma.Error401Unauthorized("Invalid Authorization header format. Expected 'Bearer <token>'")
		}
		token := authHeader[len(bearerPrefix):]

		// Validate Registry JWT token
		claims, err := jwtManager.ValidateToken(ctx, token)
		if err != nil {
			return nil, huma.Error401Unauthorized("Invalid or expired Registry JWT token", err)
		}

		// Validate that only allowed extension fields are present
		if err := model.ValidatePublishRequestExtensions(input.RawBody); err != nil {
			return nil, huma.Error400BadRequest("Invalid request format", err)
		}

		// Get current server to check permissions against existing name
		currentServer, err := registry.GetByID(input.ID)
		if err != nil {
			if errors.Is(err, database.ErrNotFound) {
				return nil, huma.Error404NotFound("Server not found")
			}
			return nil, huma.Error500InternalServerError("Failed to get current server", err)
		}

		// Verify edit permissions for this server using the existing server name
		if !jwtManager.HasPermission(currentServer.Server.Name, auth.PermissionActionEdit, claims.Permissions) {
			return nil, huma.Error403Forbidden("You do not have edit permissions for this server")
		}

		// Parse the validated request body
		var editRequest model.PublishRequest
		if err := json.Unmarshal(input.RawBody, &editRequest); err != nil {
			return nil, huma.Error400BadRequest("Invalid JSON format", err)
		}

		// Validate the server detail
		validator := validators.NewObjectValidator()
		if err := validator.Validate(&editRequest.Server); err != nil {
			return nil, huma.Error400BadRequest(err.Error())
		}

		// Prevent renaming servers
		if currentServer.Server.Name != editRequest.Server.Name {
			return nil, huma.Error400BadRequest("Cannot rename server")
		}

		// Prevent undeleting servers - once deleted, they stay deleted
		if currentServer.Server.Status == model.ServerStatusDeleted && editRequest.Server.Status != model.ServerStatusDeleted {
			return nil, huma.Error400BadRequest("Cannot change status of deleted server. Deleted servers cannot be undeleted.")
		}

		// Edit the server
		updatedServer, err := registry.EditServer(input.ID, editRequest)
		if err != nil {
			if errors.Is(err, database.ErrNotFound) {
				return nil, huma.Error404NotFound("Server not found")
			}
			return nil, huma.Error400BadRequest("Failed to edit server", err)
		}

		return &Response[model.ServerResponse]{
			Body: *updatedServer,
		}, nil
	})
}