// 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 alloydbainl

import (
	"context"
	"fmt"
	"strings"

	yaml "github.com/goccy/go-yaml"
	"github.com/googleapis/genai-toolbox/internal/embeddingmodels"
	"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 = "alloydb-ai-nl"

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" validate:"required"`
	NLConfig           string                `yaml:"nlConfig" validate:"required"`
	AuthRequired       []string              `yaml:"authRequired"`
	NLConfigParameters parameters.Parameters `yaml:"nlConfigParameters"`
}

// 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) {
	numParams := len(cfg.NLConfigParameters)
	quotedNameParts := make([]string, 0, numParams)
	placeholderParts := make([]string, 0, numParams)

	for i, paramDef := range cfg.NLConfigParameters {
		name := paramDef.GetName()
		escapedName := strings.ReplaceAll(name, "'", "''") // Escape for SQL literal
		quotedNameParts = append(quotedNameParts, fmt.Sprintf("'%s'", escapedName))
		placeholderParts = append(placeholderParts, fmt.Sprintf("$%d", i+3)) // $1, $2 reserved
	}

	var paramNamesSQL string
	var paramValuesSQL string

	if numParams > 0 {
		paramNamesSQL = fmt.Sprintf("ARRAY[%s]", strings.Join(quotedNameParts, ", "))
		paramValuesSQL = fmt.Sprintf("ARRAY[%s]", strings.Join(placeholderParts, ", "))
	} else {
		paramNamesSQL = "ARRAY[]::TEXT[]"
		paramValuesSQL = "ARRAY[]::TEXT[]"
	}

	// execute_nl_query is the AlloyDB AI function that executes the natural language query
	// The first parameter is the natural language query, which is passed as $1
	// The second parameter is the NLConfig, which is passed as a $2
	// The following params are the list of PSV values passed to the NLConfig
	// Example SQL statement being executed:
	// SELECT alloydb_ai_nl.execute_nl_query(nl_question => 'How many tickets do I have?', nl_config_id => 'cymbal_air_nl_config', param_names => ARRAY ['user_email'], param_values => ARRAY ['hailongli@google.com']);
	stmtFormat := "SELECT alloydb_ai_nl.execute_nl_query(nl_question => $1, nl_config_id => $2, param_names => %s, param_values => %s);"
	stmt := fmt.Sprintf(stmtFormat, paramNamesSQL, paramValuesSQL)

	newQuestionParam := parameters.NewStringParameter(
		"question",                              // name
		"The natural language question to ask.", // description
	)

	cfg.NLConfigParameters = append([]parameters.Parameter{newQuestionParam}, cfg.NLConfigParameters...)

	mcpManifest := tools.GetMcpManifest(cfg.Name, cfg.Description, cfg.AuthRequired, cfg.NLConfigParameters, nil)

	t := Tool{
		Config:      cfg,
		Parameters:  cfg.NLConfigParameters,
		Statement:   stmt,
		manifest:    tools.Manifest{Description: cfg.Description, Parameters: cfg.NLConfigParameters.Manifest(), AuthRequired: cfg.AuthRequired},
		mcpManifest: mcpManifest,
	}

	return t, nil
}

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

type Tool struct {
	Config
	Parameters  parameters.Parameters `yaml:"parameters"`
	Statement   string
	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
	}

	sliceParams := params.AsSlice()
	allParamValues := make([]any, len(sliceParams)+1)
	allParamValues[0] = fmt.Sprintf("%s", sliceParams[0]) // nl_question
	allParamValues[1] = t.NLConfig                        // nl_config
	for i, param := range sliceParams[1:] {
		allParamValues[i+2] = fmt.Sprintf("%s", param)
	}

	resp, err := source.RunSQL(ctx, t.Statement, allParamValues)
	if err != nil {
		return nil, fmt.Errorf("%w. Query: %v , Values: %v. Toolbox v0.19.0+ is only compatible with AlloyDB AI NL v1.0.3+. Please ensure that you are using the latest AlloyDB AI NL extension", err, t.Statement, allParamValues)
	}
	return resp, nil
}

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

func (t Tool) EmbedParams(ctx context.Context, paramValues parameters.ParamValues, embeddingModelsMap map[string]embeddingmodels.EmbeddingModel) (parameters.ParamValues, error) {
	return parameters.EmbedParams(ctx, t.Parameters, paramValues, embeddingModelsMap, nil)
}

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
}
