// Copyright 2026 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 postgresliststoredprocedure

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

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

const resourceType string = "postgres-list-stored-procedure"

const listStoredProcedure = `
    SELECT
          n.nspname AS schema_name,
          p.proname AS name,
          r.rolname AS owner,
          l.lanname AS language,
          pg_catalog.pg_get_functiondef(p.oid) AS definition,
          pg_catalog.obj_description(p.oid, 'pg_proc') AS description
      FROM pg_catalog.pg_proc p
      JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace
      JOIN pg_catalog.pg_roles r ON r.oid = p.proowner
      JOIN pg_catalog.pg_language l ON l.oid = p.prolang
      WHERE
          p.prokind = 'p' AND
          ($1::text IS NULL OR r.rolname LIKE '%' || $1::text || '%') AND
          ($2::text IS NULL OR n.nspname LIKE '%' || $2::text || '%')
      ORDER BY n.nspname, p.proname
      LIMIT
        COALESCE($3::int, 20);
`

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 {
	PostgresPool() *pgxpool.Pool
}

// validate compatible sources are still compatible
var _ compatibleSource = &alloydbpg.Source{}
var _ compatibleSource = &cloudsqlpg.Source{}
var _ compatibleSource = &postgres.Source{}

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"`
}

var _ tools.ToolConfig = Config{}

func (cfg Config) ToolConfigType() string {
	return resourceType
}

func (cfg Config) Initialize(context.Context) (tools.Tool, error) {
	allParameters := parameters.Parameters{
		parameters.NewStringParameter("role_name", "Optional: The owner name to filter the stored procedures by. Defaults to NULL.", parameters.WithStringRequired(false)),
		parameters.NewStringParameter("schema_name", "Optional: The schema name to filter the stored procedures by. Defaults to NULL.", parameters.WithStringRequired(false)),
		parameters.NewIntParameter("limit", "Optional: The maximum number of stored procedures to return. Defaults to 20.", parameters.WithIntDefault(20)),
	}

	if cfg.Description == "" {
		cfg.Description = "Retrieves stored procedure metadata returning schema name, procedure name, procedure owner, language, definition, and description, filtered by optional role name (procedure owner), schema name, and limit (default 20)."
	}

	return Tool{
		BaseTool: tools.NewBaseTool(
			cfg,
			tools.GetAnnotationsOrDefault(cfg.Annotations, tools.NewReadOnlyAnnotations),
			tools.Manifest{Description: cfg.Description, Parameters: allParameters.Manifest(), AuthRequired: cfg.AuthRequired},
			allParameters,
		),
	}, nil
}

var _ tools.Tool = Tool{}

type Tool struct {
	tools.BaseTool[Config]
}

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()

	newParams, err := parameters.GetParams(t.StaticParameters, paramsMap)
	if err != nil {
		return nil, util.NewAgentError("unable to extract standard params", err)
	}
	sliceParams := newParams.AsSlice()

	results, err := source.PostgresPool().Query(ctx, listStoredProcedure, sliceParams...)
	if err != nil {
		return nil, util.ProcessGeneralError(err)
	}
	defer results.Close()

	fields := results.FieldDescriptions()
	var out []map[string]any

	for results.Next() {
		values, err := results.Values()
		if err != nil {
			return nil, util.NewClientServerError("unable to parse row", http.StatusInternalServerError, err)
		}
		rowMap := make(map[string]any)
		for i, field := range fields {
			rowMap[string(field.Name)] = values[i]
		}
		out = append(out, rowMap)
	}

	return out, nil
}

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