// Package catalogclient is the shared HTTP client to catalogd.
// ingestd uses Register; queryd (D5+) uses List for view registration.
// Symmetric in shape with internal/catalogd/store_client.go: thin
// wrapper, drain-and-close discipline, sentinel errors for 4xx
// classes that the handler maps back to HTTP.
package catalogclient

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	"git.agentview.dev/profit/golangLAKEHOUSE/internal/catalogd"
)

// Client talks HTTP to catalogd's /catalog/* routes.
type Client struct {
	baseURL string
	hc      *http.Client
}

// ErrFingerprintConflict mirrors catalogd's 409 — same name,
// different schema fingerprint.
var ErrFingerprintConflict = errors.New("catalogclient: catalogd reports schema fingerprint conflict (409)")

// New builds a client against catalogd's base URL
// (e.g. "http://127.0.0.1:3212").
func New(baseURL string) *Client {
	return &Client{
		baseURL: strings.TrimRight(baseURL, "/"),
		hc:      &http.Client{Timeout: 30 * time.Second},
	}
}

// RegisterRequest mirrors catalogd's POST /catalog/register body.
type RegisterRequest struct {
	Name              string            `json:"name"`
	SchemaFingerprint string            `json:"schema_fingerprint"`
	Objects           []catalogd.Object `json:"objects"`
	RowCount          *int64            `json:"row_count,omitempty"`
}

// RegisterResponse mirrors catalogd's 200/conflict response.
type RegisterResponse struct {
	Manifest *catalogd.Manifest `json:"manifest"`
	Existing bool               `json:"existing"`
}

// listResponse mirrors catalogd's GET /catalog/list shape:
//
//	{"manifests": [...], "count": N}
type listResponse struct {
	Manifests []*catalogd.Manifest `json:"manifests"`
	Count     int                  `json:"count"`
}

// Register POSTs to /catalog/register. Returns ErrFingerprintConflict
// on 409, the decoded response on 200, an error on anything else.
func (c *Client) Register(ctx context.Context, req *RegisterRequest) (*RegisterResponse, error) {
	body, err := json.Marshal(req)
	if err != nil {
		return nil, fmt.Errorf("marshal register: %w", err)
	}
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/catalog/register", bytes.NewReader(body))
	if err != nil {
		return nil, fmt.Errorf("register req: %w", err)
	}
	httpReq.Header.Set("Content-Type", "application/json")
	httpReq.ContentLength = int64(len(body))

	resp, err := c.hc.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("register do: %w", err)
	}
	defer drainAndClose(resp.Body)

	if resp.StatusCode == http.StatusConflict {
		preview, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
		return nil, fmt.Errorf("%w: %s", ErrFingerprintConflict, string(preview))
	}
	if resp.StatusCode != http.StatusOK {
		preview, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
		return nil, fmt.Errorf("register status %d: %s", resp.StatusCode, string(preview))
	}
	var out RegisterResponse
	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
		return nil, fmt.Errorf("register decode: %w", err)
	}
	return &out, nil
}

// List GETs /catalog/list and returns every registered manifest.
// queryd (D5+) uses this for view registration; future operator
// tooling can use it for catalog inspection.
//
// Manifests come back sorted by name (catalogd's contract). The
// response also carries a count, which is dropped here — callers
// can take len(manifests) instead of paying for both.
func (c *Client) List(ctx context.Context) ([]*catalogd.Manifest, error) {
	httpReq, err := http.NewRequestWithContext(ctx, http.MethodGet, c.baseURL+"/catalog/list", nil)
	if err != nil {
		return nil, fmt.Errorf("list req: %w", err)
	}
	resp, err := c.hc.Do(httpReq)
	if err != nil {
		return nil, fmt.Errorf("list do: %w", err)
	}
	defer drainAndClose(resp.Body)

	if resp.StatusCode != http.StatusOK {
		preview, _ := io.ReadAll(io.LimitReader(resp.Body, 256))
		return nil, fmt.Errorf("list status %d: %s", resp.StatusCode, string(preview))
	}
	var out listResponse
	if err := json.NewDecoder(resp.Body).Decode(&out); err != nil {
		return nil, fmt.Errorf("list decode: %w", err)
	}
	return out.Manifests, nil
}

// drainAndClose mirrors the catalogd store_client helper — drain a
// bounded amount of body bytes before close so HTTP/1.1 keep-alive
// pool reuse stays healthy on error paths.
func drainAndClose(body io.ReadCloser) {
	_, _ = io.Copy(io.Discard, io.LimitReader(body, 64<<10))
	_ = body.Close()
}