package agents

import (
	"context"
	"embed"
	"encoding/json"
	"fmt"
	"io/fs"
	"strings"

	"g.fc.run/ai/byre/internal/mcp"
)

//go:embed kb/*.md
var kbFiles embed.FS

var kb, kbIndex = loadKB()

func loadKB() (map[string]string, string) {
	entries, err := fs.ReadDir(kbFiles, "kb")
	if err != nil {
		panic(err)
	}
	articles := map[string]string{}
	index := ""
	for _, e := range entries {
		b, err := kbFiles.ReadFile("kb/" + e.Name())
		if err != nil {
			panic(err)
		}
		summary, body, _ := strings.Cut(string(b), "\n")
		topic := strings.TrimSuffix(e.Name(), ".md")
		articles[topic] = strings.TrimSpace(body)
		index += fmt.Sprintf("\n- %s: %s", topic, summary)
	}
	return articles, index
}

func (m *Manager) readKnowledgeTool() mcp.Tool {
	return mcp.Tool{
		Name: "read_knowledge",
		Description: "Read an article from byre's knowledge base: how byre features work that agents need only now and then. " +
			"Read the matching article before working on or answering about one of these topics:" + kbIndex,
		InputSchema: json.RawMessage(`{
			"type": "object",
			"properties": {
				"topic": {"type": "string", "description": "The article's topic, as listed."}
			},
			"required": ["topic"]
		}`),
		Handler: func(ctx context.Context, raw json.RawMessage) (string, error) {
			args := struct {
				Topic string `json:"topic"`
			}{}
			err := json.Unmarshal(raw, &args)
			if err != nil {
				return "", fmt.Errorf("malformed read_knowledge call: %w", err)
			}
			body, ok := kb[args.Topic]
			if !ok {
				return "", fmt.Errorf("no article %q; the topics are:%s", args.Topic, kbIndex)
			}
			return body, nil
		},
	}
}