// Package apprise delivers notifications through the house Apprise API.
//
// Apprise is the shared notification gateway (AGENTS.md §8). The Email Agent
// uses it only to deliver the daily summary by email (FR-10). The client speaks
// the standard Apprise API server shape:
//
//	POST {base}/notify/{key}   JSON {"title","body","type"}
//	POST {base}/notify         JSON {"urls","title","body","type"}  (stateless)
//
// A key names a stored Apprise configuration. When no key is set the client
// uses the stateless form with an explicit list of Apprise URLs.
package apprise

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

// Client posts a notification to one Apprise API server.
type Client struct {
	BaseURL string
	// Key names a stored Apprise configuration. Empty means stateless mode.
	Key string
	// URLs is the stateless destination list, used when Key is empty.
	URLs []string
	// Token is sent as a bearer token when the Apprise API is protected.
	Token string
	HTTP  *http.Client
}

// New builds a client. baseURL is the Apprise API root, e.g.
// http://192.168.20.35:8210. A zero timeout defaults to ten seconds.
func New(baseURL, key string, urls []string, token string, timeout time.Duration) *Client {
	if timeout <= 0 {
		timeout = 10 * time.Second
	}
	return &Client{
		BaseURL: strings.TrimRight(baseURL, "/"),
		Key:     strings.TrimSpace(key),
		URLs:    urls,
		Token:   token,
		HTTP:    &http.Client{Timeout: timeout},
	}
}

// Configured reports whether a delivery can be attempted.
func (c *Client) Configured() bool {
	if c == nil || strings.TrimSpace(c.BaseURL) == "" {
		return false
	}
	return c.Key != "" || len(c.URLs) > 0
}

// notifyBody is the Apprise API request body. `type` selects the notification
// class; the daily summary is informational.
type notifyBody struct {
	URLs  []string `json:"urls,omitempty"`
	Title string   `json:"title,omitempty"`
	Body  string   `json:"body"`
	Type  string   `json:"type,omitempty"`
}

// Send delivers one notification titled title with the given text body.
func (c *Client) Send(ctx context.Context, title, body string) error {
	if !c.Configured() {
		return fmt.Errorf("apprise is not configured")
	}
	payload := notifyBody{Title: title, Body: body, Type: "info"}
	url := c.BaseURL + "/notify"
	if c.Key != "" {
		url += "/" + c.Key
	} else {
		payload.URLs = c.URLs
	}

	raw, err := json.Marshal(payload)
	if err != nil {
		return fmt.Errorf("encode apprise request: %w", err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(raw))
	if err != nil {
		return fmt.Errorf("build apprise request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json; charset=utf-8")
	if c.Token != "" {
		req.Header.Set("Authorization", "Bearer "+c.Token)
	}

	resp, err := c.HTTP.Do(req)
	if err != nil {
		return fmt.Errorf("post apprise: %w", err)
	}
	defer resp.Body.Close()
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("post apprise: status %d", resp.StatusCode)
	}
	return nil
}