// 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 valkey

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/valkey-io/valkey-go"
)

const kind string = "valkey"

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 {
	ValkeyClient() valkey.Client
	RunCommand(context.Context, [][]string) (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"`
	Commands     [][]string            `yaml:"commands" validate:"required"`
	AuthRequired []string              `yaml:"authRequired"`
	Parameters   parameters.Parameters `yaml:"parameters"`
}

// 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) {
	mcpManifest := tools.GetMcpManifest(cfg.Name, cfg.Description, cfg.AuthRequired, cfg.Parameters, nil)

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

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

type Tool struct {
	Config
	manifest    tools.Manifest
	mcpManifest tools.McpManifest
}

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
	}

	// Replace parameters
	commands, err := replaceCommandsParams(t.Commands, t.Parameters, params)
	if err != nil {
		return nil, fmt.Errorf("error replacing commands' parameters: %s", err)
	}
	return source.RunCommand(ctx, commands)
}

// replaceCommandsParams is a helper function to replace parameters in the commands
func replaceCommandsParams(commands [][]string, params parameters.Parameters, paramValues parameters.ParamValues) ([][]string, error) {
	paramMap := paramValues.AsMapWithDollarPrefix()
	typeMap := make(map[string]string, len(params))
	for _, p := range params {
		placeholder := "$" + p.GetName()
		typeMap[placeholder] = p.GetType()
	}

	newCommands := make([][]string, len(commands))
	for i, cmd := range commands {
		newCmd := make([]string, 0)
		for _, part := range cmd {
			v, ok := paramMap[part]
			if !ok {
				// Command part is not a Parameter placeholder
				newCmd = append(newCmd, part)
				continue
			}
			if typeMap[part] == "array" {
				for _, item := range v.([]any) {
					// Nested arrays will only be expanded once
					// e.g., [A, [B, C]]  --> ["A", "[B C]"]
					newCmd = append(newCmd, fmt.Sprintf("%s", item))
				}
				continue
			}
			newCmd = append(newCmd, fmt.Sprintf("%s", v))
		}
		newCommands[i] = newCmd
	}
	return newCommands, 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) 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) ToConfig() tools.ToolConfig {
	return t.Config
}

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