// 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 spannercreateinstance

import (
	"context"
	"fmt"

	"cloud.google.com/go/spanner/admin/instance/apiv1/instancepb"
	"github.com/goccy/go-yaml"
	"github.com/googleapis/genai-toolbox/internal/sources"
	"github.com/googleapis/genai-toolbox/internal/sources/spanneradmin"
	"github.com/googleapis/genai-toolbox/internal/tools"
	"github.com/googleapis/genai-toolbox/internal/util/parameters"
)

const kind string = "spanner-create-instance"

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

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

// Config defines the configuration for the create-instance tool.
type Config struct {
	Name         string   `yaml:"name" validate:"required"`
	Kind         string   `yaml:"kind" validate:"required"`
	Description  string   `yaml:"description"`
	Source       string   `yaml:"source" validate:"required"`
	AuthRequired []string `yaml:"authRequired"`
}

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

// ToolConfigKind returns the kind of the tool.
func (cfg Config) ToolConfigKind() string {
	return kind
}

// Initialize initializes the tool from the configuration.
func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error) {
	rawS, ok := srcs[cfg.Source]
	if !ok {
		return nil, fmt.Errorf("no source named %q configured", cfg.Source)
	}
	s, ok := rawS.(*spanneradmin.Source)
	if !ok {
		return nil, fmt.Errorf("invalid source for %q tool: source kind must be `spanner-admin`", kind)
	}

	project := s.DefaultProject
	var projectParam parameters.Parameter
	if project != "" {
		projectParam = parameters.NewStringParameterWithDefault("project", project, "The GCP project ID.")
	} else {
		projectParam = parameters.NewStringParameter("project", "The project ID")
	}

	allParameters := parameters.Parameters{
		projectParam,
		parameters.NewStringParameter("instanceId", "The ID of the instance"),
		parameters.NewStringParameter("displayName", "The display name of the instance"),
		parameters.NewStringParameter("config", "The instance configuration (e.g., regional-us-central1)"),
		parameters.NewIntParameter("nodeCount", "The number of nodes"),
		parameters.NewIntParameter("processingUnits", "The number of processing units"),
		parameters.NewStringParameter("edition", "The edition of the instance (STANDARD, ENTERPRISE, ENTERPRISE_PLUS)"),
	}

	paramManifest := allParameters.Manifest()

	description := cfg.Description
	if description == "" {
		description = "Creates a Spanner instance."
	}
	mcpManifest := tools.GetMcpManifest(cfg.Name, description, cfg.AuthRequired, allParameters, nil)

	return Tool{
		Config:      cfg,
		Source:      s,
		AllParams:   allParameters,
		manifest:    tools.Manifest{Description: description, Parameters: paramManifest, AuthRequired: cfg.AuthRequired},
		mcpManifest: mcpManifest,
	}, nil
}

// Tool represents the create-instance tool.
type Tool struct {
	Config
	Source      *spanneradmin.Source
	AllParams   parameters.Parameters
	manifest    tools.Manifest
	mcpManifest tools.McpManifest
}

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

// Invoke executes the tool's logic.
func (t Tool) Invoke(ctx context.Context, resourceMgr tools.SourceProvider, params parameters.ParamValues, accessToken tools.AccessToken) (any, error) {
	paramsMap := params.AsMap()

	project, _ := paramsMap["project"].(string)
	instanceId, _ := paramsMap["instanceId"].(string)
	displayName, _ := paramsMap["displayName"].(string)
	config, _ := paramsMap["config"].(string)
	nodeCount, _ := paramsMap["nodeCount"].(int)
	processingUnits, _ := paramsMap["processingUnits"].(int)
	editionStr, _ := paramsMap["edition"].(string)

	if (nodeCount > 0 && processingUnits > 0) || (nodeCount == 0 && processingUnits == 0) {
		return nil, fmt.Errorf("one of nodeCount or processingUnits must be positive, and the other must be 0")
	}

	client, err := t.Source.GetClient(ctx, string(accessToken))
	if err != nil {
		return nil, err
	}
	if t.Source.UseClientAuthorization() {
		defer client.Close()
	}

	parent := fmt.Sprintf("projects/%s", project)
	instanceConfig := fmt.Sprintf("projects/%s/instanceConfigs/%s", project, config)

	var edition instancepb.Instance_Edition
	switch editionStr {
	case "STANDARD":
		edition = instancepb.Instance_STANDARD
	case "ENTERPRISE":
		edition = instancepb.Instance_ENTERPRISE
	case "ENTERPRISE_PLUS":
		edition = instancepb.Instance_ENTERPRISE_PLUS
	default:
		edition = instancepb.Instance_EDITION_UNSPECIFIED
	}

	// Construct the instance object
	instance := &instancepb.Instance{
		Config:          instanceConfig,
		DisplayName:     displayName,
		Edition:         edition,
		NodeCount:       int32(nodeCount),
		ProcessingUnits: int32(processingUnits),
	}

	req := &instancepb.CreateInstanceRequest{
		Parent:     parent,
		InstanceId: instanceId,
		Instance:   instance,
	}

	op, err := client.CreateInstance(ctx, req)
	if err != nil {
		return nil, fmt.Errorf("failed to create instance: %w", err)
	}

	// Wait for the operation to complete
	resp, err := op.Wait(ctx)
	if err != nil {
		return nil, fmt.Errorf("failed to wait for create instance operation: %w", err)
	}

	return resp, nil
}

// ParseParams parses the parameters for the tool.
func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (parameters.ParamValues, error) {
	return parameters.ParseParams(t.AllParams, data, claims)
}

// Manifest returns the tool's manifest.
func (t Tool) Manifest() tools.Manifest {
	return t.manifest
}

// McpManifest returns the tool's MCP manifest.
func (t Tool) McpManifest() tools.McpManifest {
	return t.mcpManifest
}

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

func (t Tool) RequiresClientAuthorization(resourceMgr tools.SourceProvider) bool {
	return t.Source.UseClientAuthorization()
}

func (t Tool) GetAuthTokenHeaderName() string {
	return "Authorization"
}