package client

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

	"task/internal/daemon/api"
)

// Client talks to the local JSON daemon over a Unix socket.
type Client struct {
	http   *http.Client
	kind   string // tui | cli | mcp
	token  string // bearer for mcp
	project string // mcp bound project
}

// Options configures a daemon client.
type Options struct {
	Socket  string
	Kind    string
	Token   string
	Project string
}

// Dial creates a client for the given Unix socket.
func Dial(opts Options) *Client {
	kind := opts.Kind
	if kind == "" {
		kind = api.ClientTUI
	}
	return &Client{
		kind:    kind,
		token:   opts.Token,
		project: opts.Project,
		http: &http.Client{
			Timeout: 60 * time.Second,
			Transport: &http.Transport{
				DialContext: func(ctx context.Context, _, _ string) (net.Conn, error) {
					var d net.Dialer
					return d.DialContext(ctx, "unix", opts.Socket)
				},
			},
		},
	}
}

func (c *Client) do(method, path string, in any, out any) error {
	var body io.Reader
	if in != nil {
		b, err := json.Marshal(in)
		if err != nil {
			return err
		}
		body = bytes.NewReader(b)
	}
	req, err := http.NewRequest(method, "http://daemon"+path, body)
	if err != nil {
		return err
	}
	if in != nil {
		req.Header.Set("Content-Type", "application/json")
	}
	req.Header.Set(api.HeaderClient, c.kind)
	if c.kind == api.ClientMCP {
		if c.token != "" {
			req.Header.Set("Authorization", "Bearer "+c.token)
		}
		if c.project != "" {
			req.Header.Set("X-TM-Project", c.project)
		}
	}
	resp, err := c.http.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}
	if resp.StatusCode >= 400 {
		var er struct {
			Error string `json:"error"`
		}
		_ = json.Unmarshal(data, &er)
		if er.Error == "" {
			er.Error = strings.TrimSpace(string(data))
		}
		if er.Error == "" {
			er.Error = resp.Status
		}
		return fmt.Errorf("%s", er.Error)
	}
	if out == nil || resp.StatusCode == http.StatusNoContent || len(data) == 0 {
		return nil
	}
	return json.Unmarshal(data, out)
}

// Health checks /v1/health.
func (c *Client) Health() error {
	return c.do(http.MethodGet, "/v1/health", nil, nil)
}