package com.paymentlink.controller.api;

import com.paymentlink.service.FlagService;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * REST API for country flags
 */
@RestController
@RequestMapping("/api/flags")
public class FlagApiController {
    
    private final FlagService flagService;
    
    public FlagApiController(FlagService flagService) {
        this.flagService = flagService;
    }
    
    /**
     * Get flag for a specific country
     * 
     * GET /api/flags/{countryCode}
     * Example: /api/flags/US, /api/flags/TR
     * 
     * @param countryCode ISO 3166-1 alpha-2 country code
     * @return Flag as base64 data URL
     */
    @GetMapping("/{countryCode}")
    public ResponseEntity<Map<String, Object>> getFlag(
            @PathVariable String countryCode) {
        
        String flag = flagService.getFlag(countryCode);
        
        Map<String, Object> response = new HashMap<>();
        
        if (flag != null) {
            response.put("success", true);
            response.put("countryCode", countryCode.toUpperCase());
            response.put("flag", flag);
            response.put("type", "image");
            return ResponseEntity.ok(response);
        } else {
            response.put("success", false);
            response.put("countryCode", countryCode.toUpperCase());
            response.put("flag", flagService.getFallbackIcon());
            response.put("type", "svg");
            response.put("message", "Flag not found, returning fallback icon");
            return ResponseEntity.ok(response);
        }
    }
    
    /**
     * Get multiple flags at once
     * 
     * POST /api/flags/batch
     * Body: { "countryCodes": ["US", "GB", "TR"] }
     * 
     * @param request Request containing list of country codes
     * @return Map of country codes to flags
     */
    @PostMapping("/batch")
    public ResponseEntity<Map<String, Object>> getFlags(
            @RequestBody BatchFlagRequest request) {
        
        Map<String, String> flags = new HashMap<>();
        
        for (String code : request.countryCodes()) {
            String flag = flagService.getFlag(code);
            if (flag != null) {
                flags.put(code.toUpperCase(), flag);
            } else {
                flags.put(code.toUpperCase(), flagService.getFallbackIcon());
            }
        }
        
        Map<String, Object> response = new HashMap<>();
        response.put("success", true);
        response.put("count", flags.size());
        response.put("flags", flags);
        
        return ResponseEntity.ok(response);
    }
    
    /**
     * Get cache statistics
     * 
     * GET /api/flags/stats
     */
    @GetMapping("/stats")
    public ResponseEntity<Map<String, Object>> getCacheStats() {
        FlagService.CacheStats stats = flagService.getCacheStats();
        
        Map<String, Object> response = new HashMap<>();
        response.put("success", true);
        response.put("cache", Map.of(
            "memorySize", stats.memorySize(),
            "diskFiles", stats.diskFiles(),
            "hitCount", stats.hitCount(),
            "missCount", stats.missCount(),
            "hitRate", stats.hitCount() + stats.missCount() > 0 
                ? (double) stats.hitCount() / (stats.hitCount() + stats.missCount()) 
                : 0.0
        ));
        
        return ResponseEntity.ok(response);
    }
    
    /**
     * Clear flag cache (admin only)
     * 
     * DELETE /api/flags/cache
     */
    @DeleteMapping("/cache")
    public ResponseEntity<Map<String, Object>> clearCache() {
        flagService.clearCache();
        
        Map<String, Object> response = new HashMap<>();
        response.put("success", true);
        response.put("message", "Flag cache cleared successfully");
        
        return ResponseEntity.ok(response);
    }
    
    /**
     * Prefetch flags for common countries
     * 
     * POST /api/flags/prefetch
     */
    @PostMapping("/prefetch")
    public ResponseEntity<Map<String, Object>> prefetchFlags(
            @RequestBody(required = false) BatchFlagRequest request) {
        
        String[] codes;
        if (request != null && request.countryCodes() != null) {
            codes = request.countryCodes().toArray(new String[0]);
        } else {
            // Default popular countries
            codes = new String[]{"US", "GB", "CA", "AU", "DE", "FR", "IT", "ES", 
                "BR", "MX", "JP", "CN", "IN", "TR", "RU", "KR"};
        }
        
        flagService.prefetchFlags(codes);
        
        Map<String, Object> response = new HashMap<>();
        response.put("success", true);
        response.put("message", "Prefetched " + codes.length + " flags");
        response.put("countryCodes", codes);
        
        return ResponseEntity.ok(response);
    }
    
    public record BatchFlagRequest(List<String> countryCodes) {}
}