// Copyright 2024 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 couchbase

import (
	"context"
	"encoding/json"
	"fmt"

	"github.com/couchbase/gocb/v2"
	yaml "github.com/goccy/go-yaml"
	"github.com/googleapis/genai-toolbox/internal/sources"
	"github.com/googleapis/genai-toolbox/internal/sources/couchbase"
	"github.com/googleapis/genai-toolbox/internal/tools"
)

const kind string = "couchbase-sql"

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 {
	CouchbaseScope() *gocb.Scope
	CouchbaseQueryScanConsistency() uint
}

// validate compatible sources are still compatible
var _ compatibleSource = &couchbase.Source{}

var compatibleSources = [...]string{couchbase.SourceKind}

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"`
	Statement          string           `yaml:"statement" validate:"required"`
	AuthRequired       []string         `yaml:"authRequired"`
	Parameters         tools.Parameters `yaml:"parameters"`
	TemplateParameters tools.Parameters `yaml:"templateParameters"`
}

// 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.(compatibleSource)
	if !ok {
		return nil, fmt.Errorf("invalid source for %q tool: source kind must be one of %q", kind, compatibleSources)
	}

	allParameters, paramManifest, paramMcpManifest, err := tools.ProcessParameters(cfg.TemplateParameters, cfg.Parameters)
	if err != nil {
		return nil, err
	}

	mcpManifest := tools.McpManifest{
		Name:        cfg.Name,
		Description: cfg.Description,
		InputSchema: paramMcpManifest,
	}
	// finish tool setup
	t := Tool{
		Name:                 cfg.Name,
		Kind:                 kind,
		Parameters:           cfg.Parameters,
		TemplateParameters:   cfg.TemplateParameters,
		AllParams:            allParameters,
		Statement:            cfg.Statement,
		Scope:                s.CouchbaseScope(),
		QueryScanConsistency: s.CouchbaseQueryScanConsistency(),
		AuthRequired:         cfg.AuthRequired,
		manifest:             tools.Manifest{Description: cfg.Description, Parameters: paramManifest, AuthRequired: cfg.AuthRequired},
		mcpManifest:          mcpManifest,
	}
	return t, nil
}

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

type Tool struct {
	Name               string           `yaml:"name"`
	Kind               string           `yaml:"kind"`
	Parameters         tools.Parameters `yaml:"parameters"`
	TemplateParameters tools.Parameters `yaml:"templateParameters"`
	AllParams          tools.Parameters `yaml:"allParams"`
	AuthRequired       []string         `yaml:"authRequired"`

	Scope                *gocb.Scope
	QueryScanConsistency uint
	Statement            string
	manifest             tools.Manifest
	mcpManifest          tools.McpManifest
}

func (t Tool) Invoke(ctx context.Context, params tools.ParamValues, accessToken tools.AccessToken) (any, error) {
	namedParamsMap := params.AsMap()
	newStatement, err := tools.ResolveTemplateParams(t.TemplateParameters, t.Statement, namedParamsMap)
	if err != nil {
		return nil, fmt.Errorf("unable to extract template params %w", err)
	}

	newParams, err := tools.GetParams(t.Parameters, namedParamsMap)
	if err != nil {
		return nil, fmt.Errorf("unable to extract standard params %w", err)
	}
	results, err := t.Scope.Query(newStatement, &gocb.QueryOptions{
		ScanConsistency: gocb.QueryScanConsistency(t.QueryScanConsistency),
		NamedParameters: newParams.AsMap(),
	})
	if err != nil {
		return nil, fmt.Errorf("unable to execute query: %w", err)
	}

	var out []any
	for results.Next() {
		var result json.RawMessage
		err := results.Row(&result)
		if err != nil {
			return nil, fmt.Errorf("error processing row: %w", err)
		}
		out = append(out, result)
	}
	return out, nil
}

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

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

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

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

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