package api

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

	"github.com/nutcas3/telecom-platform/apps/cli/internal/types"
)

// Client represents the API client for the telecom platform
type Client struct {
	baseURL    string
	apiKey     string
	httpClient *http.Client
}

// NewClient creates a new API client from CLI config
func NewClient(cfg *types.CLIConfig) *Client {
	if cfg == nil {
		cfg = &types.CLIConfig{APIEndpoint: "http://localhost:8000"}
	}
	return &Client{
		baseURL: cfg.APIEndpoint,
		apiKey:  cfg.APIToken,
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

// BaseURL returns the configured API endpoint (useful for UI display).
func (c *Client) BaseURL() string {
	return c.baseURL
}

// doGetJSON performs a GET request and decodes JSON into out
func (c *Client) doGetJSON(path string, out any) error {
	req, err := http.NewRequest("GET", c.baseURL+path, nil)
	if err != nil {
		return err
	}
	if c.apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+c.apiKey)
	}
	req.Header.Set("Content-Type", "application/json")
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API %s %d: %s", path, resp.StatusCode, string(body))
	}
	return json.NewDecoder(resp.Body).Decode(out)
}

// doPostJSON performs a POST request with JSON body and decodes response
func (c *Client) doPostJSON(path string, body any, out any) error {
	var buf *bytes.Buffer
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			return err
		}
		buf = bytes.NewBuffer(b)
	} else {
		buf = bytes.NewBuffer(nil)
	}
	req, err := http.NewRequest("POST", c.baseURL+path, buf)
	if err != nil {
		return err
	}
	if c.apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+c.apiKey)
	}
	req.Header.Set("Content-Type", "application/json")
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 400 {
		rb, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API %s %d: %s", path, resp.StatusCode, string(rb))
	}
	if out == nil {
		return nil
	}
	return json.NewDecoder(resp.Body).Decode(out)
}

// doDelete performs a DELETE request
func (c *Client) doDelete(path string) error {
	req, err := http.NewRequest("DELETE", c.baseURL+path, nil)
	if err != nil {
		return err
	}
	if c.apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+c.apiKey)
	}
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode >= 400 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API %s %d: %s", path, resp.StatusCode, string(body))
	}
	return nil
}

// IsConnected checks if the API server is reachable
func (c *Client) IsConnected() bool {
	url := fmt.Sprintf("%s/health", c.baseURL)

	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return false
	}

	req.Header.Set("Authorization", "Bearer "+c.apiKey)

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return false
	}
	defer resp.Body.Close()

	return resp.StatusCode == http.StatusOK
}