// 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 mongodbupdateone

import (
	"context"
	"fmt"
	"slices"

	"github.com/goccy/go-yaml"
	"github.com/googleapis/genai-toolbox/internal/sources"
	mongosrc "github.com/googleapis/genai-toolbox/internal/sources/mongodb"
	"github.com/googleapis/genai-toolbox/internal/tools"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

const kind string = "mongodb-update-one"

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
}

type Config struct {
	Name          string           `yaml:"name" validate:"required"`
	Kind          string           `yaml:"kind" validate:"required"`
	Source        string           `yaml:"source" validate:"required"`
	AuthRequired  []string         `yaml:"authRequired" validate:"required"`
	Description   string           `yaml:"description" validate:"required"`
	Database      string           `yaml:"database" validate:"required"`
	Collection    string           `yaml:"collection" validate:"required"`
	FilterPayload string           `yaml:"filterPayload" validate:"required"`
	FilterParams  tools.Parameters `yaml:"filterParams" validate:"required"`
	UpdatePayload string           `yaml:"updatePayload" validate:"required"`
	UpdateParams  tools.Parameters `yaml:"updateParams" validate:"required"`

	Canonical bool `yaml:"canonical" validate:"required"`
	Upsert    bool `yaml:"upsert"`
}

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

func (cfg Config) ToolConfigKind() string {
	return kind
}

func (cfg Config) Initialize(srcs map[string]sources.Source) (tools.Tool, error) {
	// verify source exists
	rawS, ok := srcs[cfg.Source]
	if !ok {
		return nil, fmt.Errorf("no source named %q configured", cfg.Source)
	}

	// verify the source is compatible
	s, ok := rawS.(*mongosrc.Source)
	if !ok {
		return nil, fmt.Errorf("invalid source for %q tool: source kind must be `mongodb`", kind)
	}

	// Create a slice for all parameters
	allParameters := slices.Concat(cfg.FilterParams, cfg.FilterParams, cfg.UpdateParams)

	// Verify no duplicate parameter names
	err := tools.CheckDuplicateParameters(allParameters)
	if err != nil {
		return nil, err
	}

	// Create Toolbox manifest
	paramManifest := allParameters.Manifest()

	if paramManifest == nil {
		paramManifest = make([]tools.ParameterManifest, 0)
	}

	// Create MCP manifest
	mcpManifest := tools.McpManifest{
		Name:        cfg.Name,
		Description: cfg.Description,
		InputSchema: allParameters.McpManifest(),
	}

	// finish tool setup
	return Tool{
		Name:          cfg.Name,
		Kind:          kind,
		AuthRequired:  cfg.AuthRequired,
		Collection:    cfg.Collection,
		FilterPayload: cfg.FilterPayload,
		FilterParams:  cfg.FilterParams,
		UpdatePayload: cfg.UpdatePayload,
		UpdateParams:  cfg.UpdateParams,
		Canonical:     cfg.Canonical,
		Upsert:        cfg.Upsert,
		AllParams:     allParameters,
		database:      s.Client.Database(cfg.Database),
		manifest:      tools.Manifest{Description: cfg.Description, Parameters: paramManifest, AuthRequired: cfg.AuthRequired},
		mcpManifest:   mcpManifest,
	}, nil
}

// validate interface
var _ tools.Tool = Tool{}

type Tool struct {
	Name          string   `yaml:"name"`
	Kind          string   `yaml:"kind"`
	AuthRequired  []string `yaml:"authRequired"`
	Description   string   `yaml:"description"`
	Collection    string   `yaml:"collection"`
	FilterPayload string   `yaml:"filterPayload" validate:"required"`
	FilterParams  tools.Parameters
	UpdatePayload string `yaml:"updatePayload" validate:"required"`
	UpdateParams  tools.Parameters
	AllParams     tools.Parameters
	Canonical     bool `yaml:"canonical" validation:"required"`
	Upsert        bool `yaml:"upsert"`

	database    *mongo.Database
	manifest    tools.Manifest
	mcpManifest tools.McpManifest
}

func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken tools.AccessToken) (any, error) {
	paramsMap := params.AsMap()

	filterString, err := tools.PopulateTemplateWithJSON("MongoDBUpdateOneFilter", t.FilterPayload, paramsMap)
	if err != nil {
		return nil, fmt.Errorf("error populating filter: %s", err)
	}

	var filter = bson.D{}
	err = bson.UnmarshalExtJSON([]byte(filterString), false, &filter)
	if err != nil {
		return nil, fmt.Errorf("unable to unmarshal filter string: %w", err)
	}

	updateString, err := tools.PopulateTemplateWithJSON("MongoDBUpdateOne", t.UpdatePayload, paramsMap)
	if err != nil {
		return nil, fmt.Errorf("unable to get update: %w", err)
	}

	var update = bson.D{}
	err = bson.UnmarshalExtJSON([]byte(updateString), t.Canonical, &update)
	if err != nil {
		return nil, fmt.Errorf("unable to unmarshal update string: %w", err)
	}

	res, err := t.database.Collection(t.Collection).UpdateOne(ctx, filter, update, options.Update().SetUpsert(t.Upsert))
	if err != nil {
		return nil, fmt.Errorf("error updating collection: %w", err)
	}

	return res.ModifiedCount, nil
}

func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (tools.ParamValues, error) {
	return tools.ParseParams(t.AllParams, data, claims)
}

func (t Tool) Manifest() tools.Manifest {
	return t.manifest
}

func (t Tool) McpManifest() tools.McpManifest {
	return t.mcpManifest
}

func (t Tool) Authorized(verifiedAuthServices []string) bool {
	return tools.IsAuthorized(t.AuthRequired, verifiedAuthServices)
}

func (t Tool) RequiresClientAuthorization() bool {
	return false
}
