// Package clients provides client implementations for printer integrations:
// Moonraker REST + WebSocket (Klipper-based printers) and MQTT (Bambu Lab).
package clients

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

// ── Moonraker response types ────────────────────────────────────────────────

// moonrakerRPC is the generic JSON-RPC wrapper Moonraker uses for responses.
type moonrakerRPC struct {
	Result json.RawMessage `json:"result"`
	Error  *moonrakerError `json:"error"`
}

type moonrakerError struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
}

// ── Public DTOs ─────────────────────────────────────────────────────────────

// MoonrakerPrinterInfo represents the /printer/info response.
type MoonrakerPrinterInfo struct {
	State        string `json:"state"`
	StateMessage string `json:"state_message"`
	KlippyReady  bool   `json:"klippy_ready"`
}

// MoonrakerPrintStats represents the print_stats object from
// /printer/objects/query?print_stats.
type MoonrakerPrintStats struct {
	State          string  `json:"state"`
	Filename       *string `json:"filename"`
	FilamentUsedMm float64 `json:"filament_used"`
	PrintDuration  float64 `json:"print_duration"`
	Message        *string `json:"message"`
}

// MoonrakerPrintJob represents a single entry in /server/history/items.
type MoonrakerPrintJob struct {
	JobID              string                 `json:"job_id"`
	Filename           string                 `json:"filename"`
	Status             string                 `json:"status"`
	FilamentUsedMm     float64                `json:"filament_used"`
	PrintDuration      float64                `json:"print_duration"`
	TotalDuration      float64                `json:"total_duration"`
	StartTime          *float64               `json:"start_time"`
	EndTime            *float64               `json:"end_time"`
	Metadata           map[string]interface{} `json:"metadata"`
}

// MoonrakerHistoryResponse wraps the /server/history/items response.
type MoonrakerHistoryResponse struct {
	Items      []MoonrakerPrintJob `json:"items"`
	TotalCount int                 `json:"count"`
}

// ── Client ──────────────────────────────────────────────────────────────────

// MoonrakerClient is an HTTP client for the Moonraker REST API on
// Klipper-based printers (e.g., Elegoo Centauri Carbon).
type MoonrakerClient struct {
	baseURL    string
	httpClient *http.Client
}

// NewMoonrakerClient creates a MoonrakerClient that targets the given
// base URL (e.g., "http://192.168.1.50:7125"). The internal HTTP client
// uses a 15-second timeout.
func NewMoonrakerClient(baseURL string) *MoonrakerClient {
	baseURL = strings.TrimRight(baseURL, "/")
	return &MoonrakerClient{
		baseURL: baseURL,
		httpClient: &http.Client{
			Timeout: 15 * time.Second,
		},
	}
}

// GetPrinterInfo calls GET /printer/info and returns the Klipper state.
// Returns nil when the printer is unreachable or the response cannot be parsed.
func (c *MoonrakerClient) GetPrinterInfo(ctx context.Context) (*MoonrakerPrinterInfo, error) {
	var info MoonrakerPrinterInfo
	if err := c.getJSON(ctx, "/printer/info", &info); err != nil {
		return nil, err
	}
	return &info, nil
}

// GetPrintStats calls GET /printer/objects/query?print_stats and returns
// real-time print statistics including filament consumption.
// Returns nil when no print is active or the printer is unreachable.
func (c *MoonrakerClient) GetPrintStats(ctx context.Context) (*MoonrakerPrintStats, error) {
	var stats MoonrakerPrintStats
	// Moonraker wraps the object in status.print_stats
	var wrapper struct {
		Status struct {
			PrintStats MoonrakerPrintStats `json:"print_stats"`
		} `json:"status"`
	}
	if err := c.getJSON(ctx, "/printer/objects/query?print_stats", &wrapper); err != nil {
		return nil, err
	}
	stats = wrapper.Status.PrintStats
	return &stats, nil
}

// GetPrintHistory calls GET /server/history/items and returns recent print
// jobs. limit controls the maximum number of items (clamped 1-100).
func (c *MoonrakerClient) GetPrintHistory(ctx context.Context, limit int) (*MoonrakerHistoryResponse, error) {
	if limit < 1 {
		limit = 1
	}
	if limit > 100 {
		limit = 100
	}
	var history MoonrakerHistoryResponse
	if err := c.getJSON(ctx, fmt.Sprintf("/server/history/items?limit=%d", limit), &history); err != nil {
		return nil, err
	}
	return &history, nil
}

// ── Internal helpers ────────────────────────────────────────────────────────

func (c *MoonrakerClient) getJSON(ctx context.Context, path string, target interface{}) error {
	url := c.baseURL + path

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return fmt.Errorf("moonraker: failed to build request: %w", err)
	}
	req.Header.Set("Accept", "application/json")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("moonraker: request failed (%s): %w", url, err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return fmt.Errorf("moonraker: failed to read body: %w", err)
	}

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("moonraker: %s returned HTTP %d: %s", url, resp.StatusCode, string(body))
	}

	// Moonraker wraps responses in {"result": ...}
	var rpc moonrakerRPC
	if err := json.Unmarshal(body, &rpc); err != nil {
		return fmt.Errorf("moonraker: failed to parse response: %w", err)
	}
	if rpc.Error != nil && rpc.Error.Message != "" {
		return fmt.Errorf("moonraker: api error: %s", rpc.Error.Message)
	}

	if err := json.Unmarshal(rpc.Result, target); err != nil {
		return fmt.Errorf("moonraker: failed to unmarshal result: %w (raw: %s)", err, string(rpc.Result))
	}
	return nil
}