package extension

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

// HostClient 是 sidecar / 外部进程调用基座 Host API 的客户端。
type HostClient struct {
	BaseURL  string
	Token    string
	PluginID string
	Owner    string
	HTTP     *http.Client
}

// NewHostClient 用基座注入的地址和令牌构造客户端。
func NewHostClient(baseURL, token, pluginID, owner string) *HostClient {
	return &HostClient{
		BaseURL: strings.TrimRight(baseURL, "/"), Token: token, PluginID: pluginID, Owner: owner,
		HTTP: &http.Client{Timeout: 30 * time.Second},
	}
}

func (c *HostClient) PutKV(ctx context.Context, key, value string) error {
	return c.do(ctx, http.MethodPut, "/host/v1/kv/"+url.PathEscape(key), strings.NewReader(value), nil)
}

func (c *HostClient) GetKV(ctx context.Context, key string) (string, error) {
	var out struct {
		Value string `json:"value"`
	}
	if err := c.do(ctx, http.MethodGet, "/host/v1/kv/"+url.PathEscape(key), nil, &out); err != nil {
		return "", err
	}
	return out.Value, nil
}

func (c *HostClient) Audit(ctx context.Context, action, target string, evidence json.RawMessage) error {
	body, _ := json.Marshal(map[string]any{"action": action, "target": target, "evidence": string(evidence)})
	return c.do(ctx, http.MethodPost, "/host/v1/audit", bytes.NewReader(body), nil)
}

func (c *HostClient) Dispatch(ctx context.Context, commandID string, params map[string]any) error {
	body, _ := json.Marshal(map[string]any{"params": params})
	return c.do(ctx, http.MethodPost, "/host/v1/commands/"+url.PathEscape(commandID), bytes.NewReader(body), nil)
}

func (c *HostClient) do(ctx context.Context, method, path string, body io.Reader, dest any) error {
	req, err := http.NewRequestWithContext(ctx, method, c.BaseURL+path, body)
	if err != nil {
		return err
	}
	if c.Token != "" {
		req.Header.Set("Authorization", "Bearer "+c.Token)
	}
	if c.PluginID != "" {
		req.Header.Set("X-Plugin-Id", c.PluginID)
	}
	if c.Owner != "" {
		req.Header.Set("X-Owner", c.Owner)
	}
	if body != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	client := c.HTTP
	if client == nil {
		client = http.DefaultClient
	}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	raw, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
	if resp.StatusCode >= 300 {
		return fmt.Errorf("host api %s %s: %d %s", method, path, resp.StatusCode, strings.TrimSpace(string(raw)))
	}
	if dest != nil && len(raw) > 0 {
		if err := json.Unmarshal(raw, dest); err != nil {
			return err
		}
	}
	return nil
}