package syncthing

import (
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"time"
)

// Client talks to the Syncthing REST API.
type Client struct {
	baseURL    string
	apiKey     string
	httpClient *http.Client
}

// NewClient creates a Syncthing API client.
func NewClient(baseURL, apiKey string) *Client {
	return &Client{
		baseURL: baseURL,
		apiKey:  apiKey,
		httpClient: &http.Client{
			Timeout: 10 * time.Second,
			Transport: &http.Transport{
				TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
			},
		},
	}
}

// SetAPIKey updates the API key.
func (c *Client) SetAPIKey(key string) {
	c.apiKey = key
}

// SetBaseURL updates the base URL.
func (c *Client) SetBaseURL(url string) {
	c.baseURL = url
}

func (c *Client) get(path string, noAuth bool) ([]byte, error) {
	req, err := http.NewRequest("GET", c.baseURL+path, nil)
	if err != nil {
		return nil, err
	}
	if !noAuth && c.apiKey != "" {
		req.Header.Set("X-API-Key", c.apiKey)
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(body))
	}
	return io.ReadAll(resp.Body)
}

func (c *Client) post(path string) error {
	req, err := http.NewRequest("POST", c.baseURL+path, nil)
	if err != nil {
		return err
	}
	if c.apiKey != "" {
		req.Header.Set("X-API-Key", c.apiKey)
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(body))
	}
	return nil
}

// Health checks if Syncthing is reachable (no auth required).
func (c *Client) Health() (*HealthStatus, error) {
	data, err := c.get("/rest/noauth/health", true)
	if err != nil {
		return nil, err
	}
	var s HealthStatus
	return &s, json.Unmarshal(data, &s)
}

// SystemStatus returns system status info.
func (c *Client) SystemStatus() (*SystemStatus, error) {
	data, err := c.get("/rest/system/status", false)
	if err != nil {
		return nil, err
	}
	var s SystemStatus
	return &s, json.Unmarshal(data, &s)
}

// SystemVersion returns version info.
func (c *Client) SystemVersion() (*SystemVersion, error) {
	data, err := c.get("/rest/system/version", false)
	if err != nil {
		return nil, err
	}
	var s SystemVersion
	return &s, json.Unmarshal(data, &s)
}

// SystemConnections returns all device connections.
func (c *Client) SystemConnections() (*Connections, error) {
	data, err := c.get("/rest/system/connections", false)
	if err != nil {
		return nil, err
	}
	var s Connections
	return &s, json.Unmarshal(data, &s)
}

// Config returns the full Syncthing config (folders + devices).
func (c *Client) Config() (*FullConfig, error) {
	data, err := c.get("/rest/config", false)
	if err != nil {
		return nil, err
	}
	var s FullConfig
	return &s, json.Unmarshal(data, &s)
}

// FolderStatus returns the sync status for a folder.
func (c *Client) FolderStatus(folderID string) (*FolderStatus, error) {
	data, err := c.get("/rest/db/status?folder="+folderID, false)
	if err != nil {
		return nil, err
	}
	var s FolderStatus
	return &s, json.Unmarshal(data, &s)
}

// Events long-polls for new events since the given ID.
func (c *Client) Events(since int, timeout int) ([]Event, error) {
	path := fmt.Sprintf("/rest/events?since=%d&timeout=%d", since, timeout)
	// Use a longer HTTP timeout for long-polling
	client := &http.Client{
		Timeout: time.Duration(timeout+10) * time.Second,
		Transport: &http.Transport{
			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
		},
	}
	req, err := http.NewRequest("GET", c.baseURL+path, nil)
	if err != nil {
		return nil, err
	}
	if c.apiKey != "" {
		req.Header.Set("X-API-Key", c.apiKey)
	}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(body))
	}
	var events []Event
	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	return events, json.Unmarshal(data, &events)
}

// PendingDevices returns new device requests.
func (c *Client) PendingDevices() (map[string]PendingDevice, error) {
	data, err := c.get("/rest/cluster/pending/devices", false)
	if err != nil {
		return nil, err
	}
	var s map[string]PendingDevice
	return s, json.Unmarshal(data, &s)
}

// PauseAll pauses all devices.
func (c *Client) PauseAll() error {
	return c.post("/rest/system/pause")
}

// ResumeAll resumes all devices.
func (c *Client) ResumeAll() error {
	return c.post("/rest/system/resume")
}

// RescanAll triggers a rescan of all folders.
func (c *Client) RescanAll() error {
	return c.post("/rest/db/scan")
}

// Restart restarts Syncthing.
func (c *Client) Restart() error {
	return c.post("/rest/system/restart")
}

// Shutdown stops Syncthing.
func (c *Client) Shutdown() error {
	return c.post("/rest/system/shutdown")
}