package main

import (
	"connectrpc.com/connect"
	"context"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"log"
	"os"
	"path/filepath"
	homelabv1 "pwa-homelab-mon/gen/homelab/v1"
	"strings"
)

// --- docs ---

func docHash(b []byte) string {
	h := sha256.Sum256(b)
	return hex.EncodeToString(h[:])
}

// docPath resolves a doc name safely: plain file name only, no separators, always inside docsDir.
func (s *server) docPath(name string) (string, error) {
	if filepath.Base(name) != name || filepath.Ext(name) != ".md" {
		return "", fmt.Errorf("bad doc name %q", name)
	}
	p := filepath.Join(s.docsDir, name)
	if filepath.Dir(p) != s.docsDir {
		return "", fmt.Errorf("bad doc name %q", name)
	}
	return p, nil
}

func (s *server) ListDocs(context.Context, *connect.Request[homelabv1.ListDocsRequest]) (*connect.Response[homelabv1.ListDocsResponse], error) {
	resp := &homelabv1.ListDocsResponse{}
	entries, err := os.ReadDir(s.docsDir)
	if err != nil {
		return connect.NewResponse(resp), nil // no docs dir = no docs
	}
	for _, e := range entries {
		if e.IsDir() || !strings.HasSuffix(e.Name(), ".md") {
			continue
		}
		b, err := os.ReadFile(filepath.Join(s.docsDir, e.Name()))
		if err != nil {
			continue
		}
		resp.Docs = append(resp.Docs, &homelabv1.DocMeta{Name: e.Name(), Hash: docHash(b)})
	}
	return connect.NewResponse(resp), nil
}

func (s *server) GetDoc(_ context.Context, req *connect.Request[homelabv1.GetDocRequest]) (*connect.Response[homelabv1.GetDocResponse], error) {
	p, err := s.docPath(req.Msg.GetName())
	if err != nil {
		return nil, connect.NewError(connect.CodeInvalidArgument, err)
	}
	b, err := os.ReadFile(p)
	if err != nil {
		return nil, connect.NewError(connect.CodeNotFound, err)
	}
	return connect.NewResponse(&homelabv1.GetDocResponse{Content: string(b)}), nil
}

func (s *server) SaveDoc(_ context.Context, req *connect.Request[homelabv1.SaveDocRequest]) (*connect.Response[homelabv1.SaveDocResponse], error) {
	p, err := s.docPath(req.Msg.GetName())
	if err != nil {
		return nil, connect.NewError(connect.CodeInvalidArgument, err)
	}
	content := []byte(req.Msg.GetContent())
	// ponytail: client authority — last write wins, no base-hash check; add optimistic locking if concurrent edits appear
	if err := os.WriteFile(p, content, 0o644); err != nil {
		return nil, connect.NewError(connect.CodeInternal, err)
	}
	log.Printf("doc saved: %s (%d bytes)", filepath.Base(p), len(content))
	return connect.NewResponse(&homelabv1.SaveDocResponse{Hash: docHash(content)}), nil
}