package browser

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

// Config holds the connection parameters for a Browserless instance.
type Config struct {
	// BaseURL is the HTTP base URL, e.g. "http://localhost:3000".
	BaseURL string
	// Token is the optional API token (BROWSERLESS_TOKEN env var).
	Token string
	// Timeout is the per-request HTTP timeout; defaults to 60 s.
	Timeout time.Duration
}

// contentClient implements BrowserClient using the /content endpoint.
type contentClient struct {
	cfg  Config
	http *http.Client
}

// NewContentClient returns a BrowserClient that uses POST /content.
func NewContentClient(cfg Config) BrowserClient {
	if cfg.Timeout == 0 {
		cfg.Timeout = 60 * time.Second
	}
	return &contentClient{
		cfg:  cfg,
		http: &http.Client{Timeout: cfg.Timeout},
	}
}

func (c *contentClient) Strategy() Strategy { return StrategyContent }

func (c *contentClient) GetContent(ctx context.Context, req ContentRequest) (string, error) {
	body, err := json.Marshal(req)
	if err != nil {
		return "", fmt.Errorf("content: marshal request: %w", err)
	}

	url := c.cfg.BaseURL + "/content"
	if c.cfg.Token != "" {
		url += "?token=" + c.cfg.Token
	}

	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return "", fmt.Errorf("content: build request: %w", err)
	}
	httpReq.Header.Set("Content-Type", "application/json")

	resp, err := c.http.Do(httpReq)
	if err != nil {
		return "", fmt.Errorf("content: do request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		b, _ := io.ReadAll(resp.Body)
		return "", fmt.Errorf("content: unexpected status %d: %s", resp.StatusCode, b)
	}

	raw, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("content: read body: %w", err)
	}
	return string(raw), nil
}

func (c *contentClient) ScrapePage(_ context.Context, _ ScrapeRequest) (ScrapeResponse, error) {
	return ScrapeResponse{}, fmt.Errorf("content client does not support /scrape; use NewScrapeClient")
}

func (c *contentClient) CDPSession(_ context.Context, _ string, _ CDPSessionFunc) error {
	return fmt.Errorf("content client does not support CDP; use NewCDPClient")
}

// ─── /scrape client ───────────────────────────────────────────────────────────

type scrapeClient struct {
	cfg  Config
	http *http.Client
}

// NewScrapeClient returns a BrowserClient that uses POST /scrape.
func NewScrapeClient(cfg Config) BrowserClient {
	if cfg.Timeout == 0 {
		cfg.Timeout = 60 * time.Second
	}
	return &scrapeClient{
		cfg:  cfg,
		http: &http.Client{Timeout: cfg.Timeout},
	}
}

func (c *scrapeClient) Strategy() Strategy { return StrategyScrape }

func (c *scrapeClient) GetContent(_ context.Context, _ ContentRequest) (string, error) {
	return "", fmt.Errorf("scrape client does not support /content; use NewContentClient")
}

func (c *scrapeClient) ScrapePage(ctx context.Context, req ScrapeRequest) (ScrapeResponse, error) {
	body, err := json.Marshal(req)
	if err != nil {
		return ScrapeResponse{}, fmt.Errorf("scrape: marshal request: %w", err)
	}

	url := c.cfg.BaseURL + "/scrape"
	if c.cfg.Token != "" {
		url += "?token=" + c.cfg.Token
	}

	httpReq, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewReader(body))
	if err != nil {
		return ScrapeResponse{}, fmt.Errorf("scrape: build request: %w", err)
	}
	httpReq.Header.Set("Content-Type", "application/json")

	resp, err := c.http.Do(httpReq)
	if err != nil {
		return ScrapeResponse{}, fmt.Errorf("scrape: do request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		b, _ := io.ReadAll(resp.Body)
		return ScrapeResponse{}, fmt.Errorf("scrape: unexpected status %d: %s", resp.StatusCode, b)
	}

	var result ScrapeResponse
	if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
		return ScrapeResponse{}, fmt.Errorf("scrape: decode response: %w", err)
	}
	return result, nil
}

func (c *scrapeClient) CDPSession(_ context.Context, _ string, _ CDPSessionFunc) error {
	return fmt.Errorf("scrape client does not support CDP; use NewCDPClient")
}