package crawler

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

// SeedFromAPI represents a seed URL from the Backend API
type SeedFromAPI struct {
	URL      string  `json:"url"`
	Trust    float64 `json:"trust"`
	Source   string  `json:"source"`   // GOV, EDU, UNI, etc.
	Scope    string  `json:"scope"`    // FEDERAL, STATE, etc.
	State    string  `json:"state"`    // BW, BY, etc. (optional)
	Depth    int     `json:"depth"`    // Crawl depth for this seed
	Category string  `json:"category"` // Category name
}

// SeedsExportResponse represents the API response from /seeds/export/for-crawler
type SeedsExportResponse struct {
	Seeds      []SeedFromAPI `json:"seeds"`
	Total      int           `json:"total"`
	ExportedAt string        `json:"exported_at"`
}

// APIClient handles communication with the Python Backend
type APIClient struct {
	baseURL    string
	httpClient *http.Client
}

// NewAPIClient creates a new API client for fetching seeds
func NewAPIClient(backendURL string) *APIClient {
	return &APIClient{
		baseURL: backendURL,
		httpClient: &http.Client{
			Timeout: 30 * time.Second,
		},
	}
}

// FetchSeeds retrieves enabled seeds from the Backend API
func (c *APIClient) FetchSeeds(ctx context.Context) (*SeedsExportResponse, error) {
	url := fmt.Sprintf("%s/v1/edu-search/seeds/export/for-crawler", c.baseURL)

	req, err := http.NewRequestWithContext(ctx, "GET", url, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Accept", "application/json")
	req.Header.Set("User-Agent", "EduSearchCrawler/1.0")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to fetch seeds: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return nil, fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(body))
	}

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

	var result SeedsExportResponse
	if err := json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	return &result, nil
}

// CrawlStatusReport represents a crawl status to report to the Backend
type CrawlStatusReport struct {
	SeedURL          string  `json:"seed_url"`
	Status           string  `json:"status"` // "success", "error", "partial"
	DocumentsCrawled int     `json:"documents_crawled"`
	ErrorMessage     string  `json:"error_message,omitempty"`
	CrawlDuration    float64 `json:"crawl_duration_seconds"`
}

// CrawlStatusResponse represents the response from crawl status endpoint
type CrawlStatusResponse struct {
	Success bool   `json:"success"`
	SeedURL string `json:"seed_url"`
	Message string `json:"message"`
}

// BulkCrawlStatusResponse represents the response from bulk crawl status endpoint
type BulkCrawlStatusResponse struct {
	Updated int      `json:"updated"`
	Failed  int      `json:"failed"`
	Errors  []string `json:"errors"`
}

// ReportStatus sends crawl status for a single seed to the Backend
func (c *APIClient) ReportStatus(ctx context.Context, report *CrawlStatusReport) error {
	url := fmt.Sprintf("%s/v1/edu-search/seeds/crawl-status", c.baseURL)

	body, err := json.Marshal(report)
	if err != nil {
		return fmt.Errorf("failed to marshal report: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(body))
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	req.Header.Set("User-Agent", "EduSearchCrawler/1.0")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to report status: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		respBody, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(respBody))
	}

	return nil
}

// ReportStatusBulk sends crawl status for multiple seeds in one request
func (c *APIClient) ReportStatusBulk(ctx context.Context, reports []*CrawlStatusReport) (*BulkCrawlStatusResponse, error) {
	url := fmt.Sprintf("%s/v1/edu-search/seeds/crawl-status/bulk", c.baseURL)

	payload := struct {
		Updates []*CrawlStatusReport `json:"updates"`
	}{
		Updates: reports,
	}

	body, err := json.Marshal(payload)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal reports: %w", err)
	}

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(body))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	req.Header.Set("User-Agent", "EduSearchCrawler/1.0")

	resp, err := c.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to report status: %w", err)
	}
	defer resp.Body.Close()

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("API returned status %d: %s", resp.StatusCode, string(respBody))
	}

	var result BulkCrawlStatusResponse
	if err := json.Unmarshal(respBody, &result); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	return &result, nil
}