package services

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"

	"fotbal-club/internal/config"
)

// EnsureFACRLogosProcessed triggers post-processing of FACR logos referenced
// in cached prefetch JSON files (facr_club_info.json, facr_tables.json).
// It is idempotent and safe to call multiple times.
func EnsureFACRLogosProcessed(cacheDir string) error {
	if config.AppConfig != nil && !config.AppConfig.RembgEnabled {
		return nil
	}
	var firstErr error
	clubInfo := filepath.Join(cacheDir, "facr_club_info.json")
	if _, err := os.Stat(clubInfo); err == nil {
		if err := postProcessFACRClubInfoLogos(cacheDir); err != nil && firstErr == nil {
			firstErr = fmt.Errorf("club_info: %w", err)
		}
	}
	tables := filepath.Join(cacheDir, "facr_tables.json")
	if _, err := os.Stat(tables); err == nil {
		if err := postProcessFACRTablesLogos(cacheDir); err != nil && firstErr == nil {
			firstErr = fmt.Errorf("tables: %w", err)
		}
	}
	return firstErr
}

// progress state for rembg batch
var rembgMu sync.RWMutex
var rembgRunning bool
var rembgTotal int
var rembgDone int
var rembgStarted time.Time
var rembgFinished *time.Time

// RembgStatus represents current background removal progress
type RembgStatus struct {
	Running    bool       `json:"running"`
	Total      int        `json:"total"`
	Done       int        `json:"done"`
	StartedAt  time.Time  `json:"started_at"`
	FinishedAt *time.Time `json:"finished_at,omitempty"`
}

// GetRembgStatus returns a snapshot of current rembg batch progress
func GetRembgStatus() RembgStatus {
	rembgMu.RLock()
	defer rembgMu.RUnlock()
	return RembgStatus{
		Running:    rembgRunning,
		Total:      rembgTotal,
		Done:       rembgDone,
		StartedAt:  rembgStarted,
		FinishedAt: rembgFinished,
	}
}

// StartFACRLogosBatch scans cached FACR JSONs and processes all referenced FACR logos
// using ProcessFACRLogo. Progress is tracked via GetRembgStatus. If a batch is already
// running, this call is a no-op and returns false. Otherwise returns true and starts
// a background goroutine.
func StartFACRLogosBatch(cacheDir string) bool {
	if config.AppConfig != nil && !config.AppConfig.RembgEnabled {
		return false
	}
	rembgMu.Lock()
	if rembgRunning {
		rembgMu.Unlock()
		return false
	}
	// Collect unique FACR logo URLs to determine total
	urls := collectFACRLogos(cacheDir)
	rembgRunning = true
	rembgTotal = len(urls)
	rembgDone = 0
	rembgStarted = time.Now()
	rembgFinished = nil
	rembgMu.Unlock()

	if len(urls) == 0 {
		// nothing to do; mark finished quickly
		rembgMu.Lock()
		rembgRunning = false
		now := time.Now()
		rembgFinished = &now
		rembgMu.Unlock()
		return true
	}

	go func(urlList []string) {
		defer func() {
			// Best-effort: after processing, ensure JSONs are rewritten to point to processed URLs
			_ = EnsureFACRLogosProcessed(cacheDir)
			rembgMu.Lock()
			rembgRunning = false
			now := time.Now()
			rembgFinished = &now
			rembgMu.Unlock()
		}()
		for _, u := range urlList {
			_, _ = ProcessFACRLogo(u) // best effort; skip errors
			rembgMu.Lock()
			rembgDone++
			rembgMu.Unlock()
		}
	}(urls)
	return true
}

// collectFACRLogos returns unique FACR-hosted logo URLs from cached prefetch JSONs.
func collectFACRLogos(cacheDir string) []string {
	uniq := map[string]struct{}{}
	add := func(s string) {
		s = strings.TrimSpace(s)
		if s == "" {
			return
		}
		// Only FACR sources; skip already-processed local /uploads and other hosts
		ls := strings.ToLower(s)
		if strings.HasPrefix(ls, "/uploads/") || strings.HasPrefix(ls, "/dist/") {
			return
		}
		if !strings.Contains(ls, "fotbal.cz") {
			return
		}
		uniq[s] = struct{}{}
	}
	// facr_club_info.json
	if b, err := os.ReadFile(filepath.Join(cacheDir, "facr_club_info.json")); err == nil {
		var payload struct {
			Competitions []struct {
				Matches []struct {
					HomeLogoURL string `json:"home_logo_url"`
					AwayLogoURL string `json:"away_logo_url"`
				} `json:"matches"`
			} `json:"competitions"`
		}
		if json.Unmarshal(b, &payload) == nil {
			for _, c := range payload.Competitions {
				for _, m := range c.Matches {
					add(m.HomeLogoURL)
					add(m.AwayLogoURL)
				}
			}
		}
	}
	// facr_tables.json
	if b, err := os.ReadFile(filepath.Join(cacheDir, "facr_tables.json")); err == nil {
		var payload struct {
			Competitions []struct {
				Table struct {
					Overall []struct {
						TeamLogoURL string `json:"team_logo_url"`
					} `json:"overall"`
				} `json:"table"`
			} `json:"competitions"`
		}
		if json.Unmarshal(b, &payload) == nil {
			for _, c := range payload.Competitions {
				for _, r := range c.Table.Overall {
					add(r.TeamLogoURL)
				}
			}
		}
	}
	out := make([]string, 0, len(uniq))
	for k := range uniq {
		out = append(out, k)
	}
	return out
}