package gpm

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

// Package is a gpm package
type Package struct {
	Name   string `json:"name"`
	Import string `json:"import"`
}

// Info is gpm information, such as version and list of packages
type Info struct {
	Version     string    `json:"version"`
	NumPackages int       `json:"num_packages"`
	Packages    []Package `json:"packages"`
}

// Info gets Info from a gpm server
func (c *Client) Info(ctx context.Context) (Info, error) {
	var info Info
	resp, err := c.crud(ctx, Package{}, http.MethodGet)
	if err != nil {
		return info, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return info, fmt.Errorf("could not get info: %s", resp.Status)
	}

	if err := json.NewDecoder(resp.Body).Decode(&info); err != nil {
		return info, err
	}

	return info, nil
}

// Add adds a new Package to a gpm server
func (c *Client) Add(ctx context.Context, pkg Package) error {
	resp, err := c.crud(ctx, pkg, http.MethodPost)
	if err != nil {
		return err
	}

	if resp.StatusCode != http.StatusCreated {
		return fmt.Errorf("could not add package: %s", resp.Status)
	}
	return nil
}

// Update updates a Package on a gpm server
func (c *Client) Update(ctx context.Context, pkg Package) error {
	resp, err := c.crud(ctx, pkg, http.MethodPatch)
	if err != nil {
		return err
	}

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("could not update package: %s", resp.Status)
	}

	return nil
}

// Remove removes a Package from a gpm server
func (c *Client) Remove(ctx context.Context, pkg Package) error {
	resp, err := c.crud(ctx, pkg, http.MethodDelete)
	if err != nil {
		return err
	}

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("could not remove package: %s", resp.Status)
	}

	return nil
}

// Get gets a Package from a server
func (c *Client) Get(ctx context.Context, name string) (Package, error) {
	var pkg Package
	uri := fmt.Sprintf("%s/%s", c.server, name)

	req, err := c.newRequest(ctx, http.MethodGet, uri, nil)
	if err != nil {
		return pkg, err
	}

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

	if resp.StatusCode != http.StatusOK {
		return pkg, fmt.Errorf("package not found for %s", name)
	}

	if err := json.NewDecoder(resp.Body).Decode(&pkg); err != nil {
		return pkg, err
	}

	return pkg, nil
}

func (c *Client) crud(ctx context.Context, pkg Package, method string) (*http.Response, error) {
	payload, err := json.Marshal(pkg)
	if err != nil {
		return nil, err
	}

	req, err := c.newRequest(ctx, method, c.server, bytes.NewReader(payload))
	if err != nil {
		return nil, err
	}

	return c.http.Do(req)
}