package api

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

// BaseClient provides common HTTP functionality for API clients
type BaseClient struct {
	HTTPClient *http.Client
	BaseURL    string
}

// NewBaseClient creates a new BaseClient with default settings
func NewBaseClient(baseURL string) BaseClient {
	return BaseClient{
		HTTPClient: &http.Client{Timeout: 15 * time.Second},
		BaseURL:    baseURL,
	}
}

// Get performs a GET request and decodes the JSON response
func (c *BaseClient) Get(ctx context.Context, path string, headers map[string]string, result interface{}) error {
	req, err := http.NewRequestWithContext(ctx, "GET", c.BaseURL+path, nil)
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	for k, v := range headers {
		req.Header.Set(k, v)
	}

	return c.doJSON(req, result)
}

// Post performs a POST request with JSON body and decodes the response
func (c *BaseClient) Post(ctx context.Context, path string, headers map[string]string, body interface{}, result interface{}) error {
	var bodyReader io.Reader
	if body != nil {
		jsonData, err := json.Marshal(body)
		if err != nil {
			return fmt.Errorf("failed to marshal request body: %w", err)
		}
		bodyReader = bytes.NewBuffer(jsonData)
	}

	req, err := http.NewRequestWithContext(ctx, "POST", c.BaseURL+path, bodyReader)
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}

	for k, v := range headers {
		req.Header.Set(k, v)
	}

	return c.doJSON(req, result)
}

// PostForm performs a POST request with form-encoded body
func (c *BaseClient) PostForm(ctx context.Context, path string, headers map[string]string, formData string, result interface{}) error {
	req, err := http.NewRequestWithContext(ctx, "POST", c.BaseURL+path, bytes.NewBufferString(formData))
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for k, v := range headers {
		req.Header.Set(k, v)
	}

	return c.doJSON(req, result)
}

// PostEmpty performs a POST request with no body and expects no response body
func (c *BaseClient) PostEmpty(ctx context.Context, path string, headers map[string]string) error {
	req, err := http.NewRequestWithContext(ctx, "POST", c.BaseURL+path, nil)
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	for k, v := range headers {
		req.Header.Set(k, v)
	}

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

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API error (status %d): %s", resp.StatusCode, string(body))
	}

	return nil
}

// Put performs a PUT request with form-encoded body
func (c *BaseClient) Put(ctx context.Context, path string, headers map[string]string, formData string, result interface{}) error {
	req, err := http.NewRequestWithContext(ctx, "PUT", c.BaseURL+path, bytes.NewBufferString(formData))
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	for k, v := range headers {
		req.Header.Set(k, v)
	}

	return c.doJSON(req, result)
}

// doJSON executes the request and decodes JSON response
func (c *BaseClient) doJSON(req *http.Request, result interface{}) error {
	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return fmt.Errorf("request failed: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API error (status %d): %s", resp.StatusCode, string(body))
	}

	if result != nil {
		if err := json.NewDecoder(resp.Body).Decode(result); err != nil {
			return fmt.Errorf("failed to decode response: %w", err)
		}
	}

	return nil
}