package cli

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

// APIClient is a REST client for the Multica server API.
// Used by ctrl subcommands (agent, runtime, status, etc.).
type APIClient struct {
	BaseURL     string
	WorkspaceID string
	HTTPClient  *http.Client
}

// NewAPIClient creates a new API client for ctrl commands.
func NewAPIClient(baseURL, workspaceID string) *APIClient {
	return &APIClient{
		BaseURL:     strings.TrimRight(baseURL, "/"),
		WorkspaceID: workspaceID,
		HTTPClient:  &http.Client{Timeout: 15 * time.Second},
	}
}

// GetJSON performs a GET request and decodes the JSON response.
func (c *APIClient) GetJSON(ctx context.Context, path string, out any) error {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.BaseURL+path, nil)
	if err != nil {
		return err
	}
	if c.WorkspaceID != "" {
		req.Header.Set("X-Workspace-ID", c.WorkspaceID)
	}

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

	if resp.StatusCode >= 400 {
		data, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
		return fmt.Errorf("GET %s returned %d: %s", path, resp.StatusCode, strings.TrimSpace(string(data)))
	}
	if out == nil {
		return nil
	}
	return json.NewDecoder(resp.Body).Decode(out)
}

// DeleteJSON performs a DELETE request.
func (c *APIClient) DeleteJSON(ctx context.Context, path string) error {
	req, err := http.NewRequestWithContext(ctx, http.MethodDelete, c.BaseURL+path, nil)
	if err != nil {
		return err
	}
	if c.WorkspaceID != "" {
		req.Header.Set("X-Workspace-ID", c.WorkspaceID)
	}

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

	if resp.StatusCode >= 400 {
		data, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
		return fmt.Errorf("DELETE %s returned %d: %s", path, resp.StatusCode, strings.TrimSpace(string(data)))
	}
	return nil
}

// PutJSON performs a PUT request with a JSON body.
func (c *APIClient) PutJSON(ctx context.Context, path string, body any, out any) error {
	data, err := json.Marshal(body)
	if err != nil {
		return err
	}

	req, err := http.NewRequestWithContext(ctx, http.MethodPut, c.BaseURL+path, bytes.NewReader(data))
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")
	if c.WorkspaceID != "" {
		req.Header.Set("X-Workspace-ID", c.WorkspaceID)
	}

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

	if resp.StatusCode >= 400 {
		respData, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
		return fmt.Errorf("PUT %s returned %d: %s", path, resp.StatusCode, strings.TrimSpace(string(respData)))
	}
	if out == nil {
		return nil
	}
	return json.NewDecoder(resp.Body).Decode(out)
}

// HealthCheck hits the /health endpoint and returns the response body.
func (c *APIClient) HealthCheck(ctx context.Context) (string, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.BaseURL+"/health", nil)
	if err != nil {
		return "", err
	}
	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	data, _ := io.ReadAll(io.LimitReader(resp.Body, 4096))
	if resp.StatusCode >= 400 {
		return "", fmt.Errorf("health check returned %d: %s", resp.StatusCode, strings.TrimSpace(string(data)))
	}
	return strings.TrimSpace(string(data)), nil
}