// 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 postgreslisttablespaces

import (
	"context"
	"fmt"

	yaml "github.com/goccy/go-yaml"
	"github.com/googleapis/genai-toolbox/internal/sources"
	"github.com/googleapis/genai-toolbox/internal/tools"
	"github.com/googleapis/genai-toolbox/internal/util/parameters"
	"github.com/jackc/pgx/v5/pgxpool"
)

const kind string = "postgres-list-tablespaces"

const listTableSpacesStatement = `
	WITH
	tablespace_info AS (
		SELECT
		spcname AS tablespace_name,
		pg_catalog.pg_get_userbyid(spcowner) AS owner_name,
		CASE
			WHEN pg_catalog.has_tablespace_privilege(oid, 'CREATE') THEN pg_tablespace_size(oid)
			ELSE NULL
			END AS size_in_bytes,
		oid,
		spcacl,
		spcoptions
		FROM
		pg_tablespace
	)
	SELECT *
	FROM
		tablespace_info
	WHERE
		($1::text IS NULL OR tablespace_name LIKE '%' || $1::text || '%')
	ORDER BY
		tablespace_name
	LIMIT COALESCE($2::int, 50);
`

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 compatibleSource interface {
	PostgresPool() *pgxpool.Pool
	RunSQL(context.Context, string, []any) (any, error)
}

type Config struct {
	Name         string   `yaml:"name" validate:"required"`
	Kind         string   `yaml:"kind" validate:"required"`
	Source       string   `yaml:"source" validate:"required"`
	Description  string   `yaml:"description"`
	AuthRequired []string `yaml:"authRequired"`
}

// 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) {
	allParameters := parameters.Parameters{
		parameters.NewStringParameterWithDefault("tablespace_name", "", "Optional: a text to filter results by tablespace name. The input is used within a LIKE clause."),
		parameters.NewIntParameterWithDefault("limit", 50, "Optional: The maximum number of rows to return."),
	}
	description := cfg.Description
	if description == "" {
		description = "Lists all tablespaces in the database. Returns the tablespace name, owner name, size in bytes(if the current user has CREATE privileges on the tablespace, otherwise NULL), internal object ID, the access control list regarding permissions, and any specific tablespace options."
	}
	mcpManifest := tools.GetMcpManifest(cfg.Name, description, cfg.AuthRequired, allParameters, nil)

	// finish tool setup
	return Tool{
		Config:    cfg,
		allParams: allParameters,
		manifest: tools.Manifest{
			Description:  cfg.Description,
			Parameters:   allParameters.Manifest(),
			AuthRequired: cfg.AuthRequired,
		},
		mcpManifest: mcpManifest,
	}, nil
}

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

type Tool struct {
	Config
	allParams   parameters.Parameters `yaml:"allParams"`
	manifest    tools.Manifest
	mcpManifest tools.McpManifest
}

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

func (t Tool) Invoke(ctx context.Context, resourceMgr tools.SourceProvider, params parameters.ParamValues, accessToken tools.AccessToken) (any, error) {
	source, err := tools.GetCompatibleSource[compatibleSource](resourceMgr, t.Source, t.Name, t.Kind)
	if err != nil {
		return nil, err
	}

	paramsMap := params.AsMap()

	tablespaceName, ok := paramsMap["tablespace_name"].(string)
	if !ok {
		return nil, fmt.Errorf("invalid 'tablespace_name' parameter; expected a string")
	}
	limit, ok := paramsMap["limit"].(int)
	if !ok {
		return nil, fmt.Errorf("invalid 'limit' parameter; expected an integer")
	}

	return source.RunSQL(ctx, listTableSpacesStatement, []any{tablespaceName, limit})
}

func (t Tool) ParseParams(data map[string]any, claims map[string]map[string]any) (parameters.ParamValues, error) {
	return parameters.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(resourceMgr tools.SourceProvider) (bool, error) {
	return false, nil
}

func (t Tool) GetAuthTokenHeaderName(resourceMgr tools.SourceProvider) (string, error) {
	return "Authorization", nil
}
