// Copyright 2025 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package alloydbcreateinstance

import (
	"context"
	"fmt"
	"net/http"

	yaml "github.com/goccy/go-yaml"
	"github.com/googleapis/mcp-toolbox/internal/sources"
	"github.com/googleapis/mcp-toolbox/internal/tools"
	"github.com/googleapis/mcp-toolbox/internal/util"
	"github.com/googleapis/mcp-toolbox/internal/util/parameters"
)

const resourceType string = "alloydb-create-instance"

func init() {
	if !tools.Register(resourceType, newConfig) {
		panic(fmt.Sprintf("tool type %q already registered", resourceType))
	}
}

func newConfig(ctx context.Context, name string, decoder *yaml.Decoder) (tools.ToolConfig, error) {
	actual := Config{ConfigBase: tools.ConfigBase{Name: name}}
	if err := decoder.DecodeContext(ctx, &actual); err != nil {
		return nil, err
	}
	return actual, nil
}

type compatibleSource interface {
	GetDefaultProject() string
	UseClientAuthorization() bool
	CreateInstance(context.Context, string, string, string, string, string, string, int, string) (any, error)
}

// Configuration for the create-instance tool.
type Config struct {
	tools.ConfigBase `yaml:",inline"`
	Type             string                 `yaml:"type" validate:"required"`
	Source           string                 `yaml:"source" validate:"required"`
	Annotations      *tools.ToolAnnotations `yaml:"annotations,omitempty"`
}

// validate interface
var _ tools.ToolConfig = Config{}

// ToolConfigType returns the type of the tool.
func (cfg Config) ToolConfigType() string {
	return resourceType
}

// Initialize initializes the tool from the configuration.
func (cfg Config) Initialize(context.Context) (tools.Tool, error) {

	if cfg.Description == "" {
		cfg.Description = "Creates a new AlloyDB instance (PRIMARY or READ_POOL) within a cluster. This is a long-running operation. This will return operation id to be used by get operations tool. Take all parameters from user in one go."
	}

	params := buildParams("")
	return Tool{
		BaseTool: tools.NewBaseTool(
			cfg,
			tools.GetAnnotationsOrDefault(cfg.Annotations, tools.NewDestructiveAnnotations),
			tools.Manifest{Description: cfg.Description, Parameters: params.Manifest(), AuthRequired: cfg.AuthRequired},
			params,
		),
	}, nil
}

// Tool represents the create-instance tool.
type Tool struct {
	tools.BaseTool[Config]
}

func (t Tool) ToConfig() tools.ToolConfig {
	return t.Cfg
}

// Invoke executes the tool's logic.
func (t Tool) Invoke(ctx context.Context, resourceMgr tools.SourceProvider, params parameters.ParamValues, accessToken tools.AccessToken) (any, util.ToolboxError) {
	source, err := tools.GetCompatibleSource[compatibleSource](resourceMgr, t.Cfg.Source, t.Cfg.Name, t.Cfg.Type)
	if err != nil {
		return nil, util.NewClientServerError("source used is not compatible with the tool", http.StatusInternalServerError, err)
	}

	paramsMap := params.AsMap()
	project, ok := paramsMap["project"].(string)
	if !ok || project == "" {
		return nil, util.NewAgentError("invalid or missing 'project' parameter; expected a non-empty string", nil)
	}

	location, ok := paramsMap["location"].(string)
	if !ok || location == "" {
		return nil, util.NewAgentError("invalid or missing 'location' parameter; expected a non-empty string", nil)
	}

	cluster, ok := paramsMap["cluster"].(string)
	if !ok || cluster == "" {
		return nil, util.NewAgentError("invalid or missing 'cluster' parameter; expected a non-empty string", nil)
	}

	instanceID, ok := paramsMap["instance"].(string)
	if !ok || instanceID == "" {
		return nil, util.NewAgentError("invalid or missing 'instance' parameter; expected a non-empty string", nil)
	}

	instanceType, ok := paramsMap["instanceType"].(string)
	if !ok || (instanceType != "READ_POOL" && instanceType != "PRIMARY") {
		return nil, util.NewAgentError("invalid 'instanceType' parameter; expected 'PRIMARY' or 'READ_POOL'", nil)
	}

	displayName, _ := paramsMap["displayName"].(string)

	var nodeCount int
	if instanceType == "READ_POOL" {
		nodeCount, ok = paramsMap["nodeCount"].(int)
		if !ok {
			return nil, util.NewAgentError("invalid 'nodeCount' parameter; expected an integer for READ_POOL", nil)
		}
	}

	resp, err := source.CreateInstance(ctx, project, location, cluster, instanceID, instanceType, displayName, nodeCount, string(accessToken))
	if err != nil {
		return nil, util.ProcessGcpError(err)
	}
	return resp, nil
}

// Authorized checks if the tool is authorized.
func (t Tool) Authorized(verifiedAuthServices []string) bool {
	return true
}

func (t Tool) RequiresClientAuthorization(resourceMgr tools.SourceProvider) (bool, error) {
	source, err := tools.GetCompatibleSource[compatibleSource](resourceMgr, t.Cfg.Source, t.Cfg.Name, t.Cfg.Type)
	if err != nil {
		return false, err
	}

	return source.UseClientAuthorization(), nil
}

// buildParams builds the tool's parameters. A non-empty project means the source has a
// configured default project, which is baked into the project param; otherwise the plain form is used.
func buildParams(project string) parameters.Parameters {
	projectParam := parameters.NewStringParameter("project", "The GCP project ID.")
	if project != "" {
		projectParam = parameters.NewStringParameter("project", "The GCP project ID. This is pre-configured; do not ask for it unless the user explicitly provides a different one.", parameters.WithStringDefault(project))
	}
	return parameters.Parameters{
		projectParam,
		parameters.NewStringParameter("location", "The location of the cluster (e.g., 'us-central1')."),
		parameters.NewStringParameter("cluster", "The ID of the cluster to create the instance in."),
		parameters.NewStringParameter("instance", "A unique ID for the new AlloyDB instance."),
		parameters.NewStringParameter("instanceType", "The type of instance to create. Valid values are: PRIMARY and READ_POOL. Default is PRIMARY", parameters.WithStringDefault("PRIMARY")),
		parameters.NewStringParameter("displayName", "An optional, user-friendly name for the instance.", parameters.WithStringRequired(false)),
		parameters.NewIntParameter("nodeCount", "The number of nodes in the read pool. Required only if instanceType is READ_POOL. Default is 1.", parameters.WithIntDefault(1)),
	}
}

// resolveParams builds the tool's parameters using the source's configured default GCP project.
func (t Tool) resolveParams(srcs map[string]sources.Source) (parameters.Parameters, error) {
	s, err := tools.GetCompatibleSourceFromMap[compatibleSource](srcs, t.Cfg.Source, t.Cfg.Name, t.Cfg.Type)
	if err != nil {
		return nil, err
	}
	return buildParams(s.GetDefaultProject()), nil
}

// GetParameters returns the tool's parameters, resolved against the source.
func (t Tool) GetParameters(srcs map[string]sources.Source) (parameters.Parameters, error) {
	return t.resolveParams(srcs)
}

// Manifest returns the tool's manifest, resolved against the source.
func (t Tool) Manifest(srcs map[string]sources.Source) (tools.Manifest, error) {
	allParameters, err := t.resolveParams(srcs)
	if err != nil {
		return tools.Manifest{}, err
	}
	return tools.Manifest{Description: t.Cfg.Description, Parameters: allParameters.Manifest(), AuthRequired: t.Cfg.AuthRequired}, nil
}