package meta

import (
	"context"
	"fmt"
	"strings"
	"time"

	"github.com/chromedp/cdproto/cdp"
	"github.com/chromedp/chromedp"
	"github.com/hireme/hireme/internal/crawler"
	"github.com/hireme/hireme/internal/logger"
)

type MetaCrawler struct{}

func NewMetaCrawler() *MetaCrawler {
	return &MetaCrawler{}
}

func (c *MetaCrawler) CanHandle(platform string) bool {
	return strings.ToLower(platform) == "meta" || strings.ToLower(platform) == "facebook"
}

func (c *MetaCrawler) DiscoverJobs(ctx context.Context, targetURL string) ([]crawler.DiscoveredJob, error) {
	opts := append(chromedp.DefaultExecAllocatorOptions[:],
		chromedp.Flag("headless", true),
		chromedp.Flag("no-sandbox", true),
		chromedp.Flag("disable-gpu", true),
		chromedp.Flag("disable-dev-shm-usage", true),
	)

	allocCtx, cancelAlloc := chromedp.NewExecAllocator(ctx, opts...)
	defer cancelAlloc()

	chromeCtx, cancelCtx := chromedp.NewContext(allocCtx)
	defer cancelCtx()

	chromeCtx, cancelTimeout := context.WithTimeout(chromeCtx, 30*time.Second)
	defer cancelTimeout()

	var nodes []*cdp.Node
	logger.Log.Infow("Navigating to Meta careers search", "url", targetURL)

	err := chromedp.Run(chromeCtx,
		chromedp.Navigate(targetURL),
		chromedp.Sleep(5*time.Second), // Wait for React and GraphQL to load
		chromedp.Nodes(`a`, &nodes, chromedp.ByQueryAll),
	)

	if err != nil {
		return nil, fmt.Errorf("chromedp navigation failed: %w", err)
	}

	var results []crawler.DiscoveredJob
	seen := make(map[string]bool)

	for _, n := range nodes {
		href := n.AttributeValue("href")
		// Meta uses /v2/jobs/..., /jobs/..., or /profile/job_details/...
		if (strings.Contains(href, "/v2/jobs/") || strings.Contains(href, "/jobs/") || strings.Contains(href, "/profile/job_details/")) && !strings.Contains(href, "jobsearch") {
			fullURL := href
			if strings.HasPrefix(href, "/") {
				fullURL = "https://www.metacareers.com" + href
			}
			
			// Extract Canonical ID from URL
			parts := strings.Split(strings.Trim(href, "/"), "/")
			canonicalID := "unknown"
			for i, p := range parts {
				if (p == "jobs" || p == "job_details") && i+1 < len(parts) {
					canonicalID = parts[i+1]
					break
				}
			}

			if !seen[fullURL] {
				seen[fullURL] = true
				results = append(results, crawler.DiscoveredJob{
					ApplyURL:    fullURL,
					CanonicalID: "meta_" + canonicalID,
				})
			}
		}
	}

	logger.Log.Infow("Meta discovery finished", "found_count", len(results))
	return results, nil
}

func (c *MetaCrawler) FetchJobDetail(ctx context.Context, applyURL string) (*crawler.ExtractedJob, error) {
	opts := append(chromedp.DefaultExecAllocatorOptions[:],
		chromedp.Flag("headless", true),
		chromedp.Flag("no-sandbox", true),
		chromedp.Flag("disable-gpu", true),
		chromedp.Flag("disable-dev-shm-usage", true),
	)

	allocCtx, cancelAlloc := chromedp.NewExecAllocator(ctx, opts...)
	defer cancelAlloc()

	chromeCtx, cancelCtx := chromedp.NewContext(allocCtx)
	defer cancelCtx()

	chromeCtx, cancelTimeout := context.WithTimeout(chromeCtx, 30*time.Second)
	defer cancelTimeout()

	logger.Log.Infow("Fetching Meta job detail", "url", applyURL)

	var titleText string
	var bodyText string

	err := chromedp.Run(chromeCtx,
		chromedp.Navigate(applyURL),
		chromedp.Sleep(5*time.Second),
		chromedp.Evaluate(`document.querySelector("h1") ? document.querySelector("h1").innerText : "Unknown Meta Title"`, &titleText),
		chromedp.Evaluate(`document.body.innerText`, &bodyText),
	)

	if err != nil {
		return nil, fmt.Errorf("chromedp navigation failed: %w", err)
	}

	// Extract ID
	parts := strings.Split(strings.Trim(applyURL, "/"), "/")
	canonicalID := "unknown"
	for i, p := range parts {
		if (p == "jobs" || p == "job_details") && i+1 < len(parts) {
			canonicalID = parts[i+1]
			break
		}
	}

	return &crawler.ExtractedJob{
		CanonicalID: "meta_" + canonicalID,
		Title:       titleText,
		Company:     "Meta",
		Location:    "Check description", // Location extraction is complex via text, leave it or parse later
		ApplyURL:    applyURL,
		RawContent:  bodyText,
	}, nil
}