import 'package:flutter/material.dart';
import 'package:google_fonts/google_fonts.dart';
import 'package:trainhub_flutter/core/constants/ui_constants.dart';
import 'package:trainhub_flutter/core/theme/app_colors.dart';
import 'package:trainhub_flutter/presentation/settings/ai_model_settings_state.dart';
import 'package:trainhub_flutter/presentation/settings/widgets/settings_action_button.dart';

class AiModelsSection extends StatelessWidget {
  const AiModelsSection({
    super.key,
    required this.modelState,
    required this.onDownload,
    required this.onValidate,
  });

  final AiModelSettingsState modelState;
  final VoidCallback onDownload;
  final VoidCallback onValidate;

  @override
  Widget build(BuildContext context) {
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(
          'AI Models',
          style: GoogleFonts.inter(
            fontSize: 13,
            fontWeight: FontWeight.w600,
            color: AppColors.textMuted,
            letterSpacing: 0.8,
          ),
        ),
        const SizedBox(height: UIConstants.spacing12),
        Container(
          decoration: BoxDecoration(
            color: AppColors.surfaceContainer,
            borderRadius: BorderRadius.circular(UIConstants.borderRadius),
            border: Border.all(color: AppColors.border),
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              const _ModelRow(
                name: 'llama-server binary',
                description: 'llama.cpp inference server (build b8130)',
                icon: Icons.terminal_rounded,
              ),
              const Divider(height: 1, color: AppColors.border),
              const _ModelRow(
                name: 'Nomic Embed v1.5 Q4_K_M',
                description: 'Text embedding model (~300 MB)',
                icon: Icons.hub_outlined,
              ),
              const Divider(height: 1, color: AppColors.border),
              const _ModelRow(
                name: 'Qwen 2.5 7B Instruct Q4_K_M',
                description: 'Chat / reasoning model (~4.7 GB)',
                icon: Icons.psychology_outlined,
              ),
              const Divider(height: 1, color: AppColors.border),
              Padding(
                padding: const EdgeInsets.all(UIConstants.spacing16),
                child: _StatusAndActions(
                  modelState: modelState,
                  onDownload: onDownload,
                  onValidate: onValidate,
                ),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _ModelRow extends StatelessWidget {
  const _ModelRow({
    required this.name,
    required this.description,
    required this.icon,
  });

  final String name;
  final String description;
  final IconData icon;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.symmetric(
        horizontal: UIConstants.spacing16,
        vertical: UIConstants.spacing12,
      ),
      child: Row(
        children: [
          Container(
            width: 36,
            height: 36,
            decoration: BoxDecoration(
              color: AppColors.surfaceContainerHigh,
              borderRadius: BorderRadius.circular(8),
            ),
            child: Icon(icon, size: 16, color: AppColors.textSecondary),
          ),
          const SizedBox(width: UIConstants.spacing12),
          Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  name,
                  style: GoogleFonts.inter(
                    fontSize: 13,
                    fontWeight: FontWeight.w500,
                    color: AppColors.textPrimary,
                  ),
                ),
                const SizedBox(height: 2),
                Text(
                  description,
                  style: GoogleFonts.inter(
                    fontSize: 12,
                    color: AppColors.textMuted,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class _StatusAndActions extends StatelessWidget {
  const _StatusAndActions({
    required this.modelState,
    required this.onDownload,
    required this.onValidate,
  });

  final AiModelSettingsState modelState;
  final VoidCallback onDownload;
  final VoidCallback onValidate;

  @override
  Widget build(BuildContext context) {
    if (modelState.isDownloading) {
      return _DownloadingView(modelState: modelState);
    }

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        _StatusBadge(validated: modelState.areModelsValidated),
        if (modelState.errorMessage != null) ...[
          const SizedBox(height: UIConstants.spacing12),
          ErrorRow(message: modelState.errorMessage!),
        ],
        const SizedBox(height: UIConstants.spacing16),
        if (!modelState.areModelsValidated)
          SettingsActionButton(
            label: 'Download AI Models (~5 GB)',
            icon: Icons.download_rounded,
            color: AppColors.accent,
            textColor: AppColors.zinc950,
            onPressed: onDownload,
          )
        else
          SettingsActionButton(
            label: 'Re-validate Files',
            icon: Icons.verified_outlined,
            color: Colors.transparent,
            textColor: AppColors.textSecondary,
            borderColor: AppColors.border,
            onPressed: onValidate,
          ),
      ],
    );
  }
}

class _StatusBadge extends StatelessWidget {
  const _StatusBadge({required this.validated});

  final bool validated;

  @override
  Widget build(BuildContext context) {
    final color = validated ? AppColors.success : AppColors.textMuted;
    final bgColor =
        validated ? AppColors.successMuted : AppColors.surfaceContainerHigh;
    final label = validated ? 'Ready' : 'Missing';
    final icon =
        validated ? Icons.check_circle_outline : Icons.radio_button_unchecked;

    return Row(
      mainAxisSize: MainAxisSize.min,
      children: [
        Text(
          'Status: ',
          style: GoogleFonts.inter(
            fontSize: 13,
            color: AppColors.textSecondary,
          ),
        ),
        const SizedBox(width: UIConstants.spacing4),
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 10, vertical: 4),
          decoration: BoxDecoration(
            color: bgColor,
            borderRadius: BorderRadius.circular(20),
          ),
          child: Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              Icon(icon, size: 13, color: color),
              const SizedBox(width: 5),
              Text(
                label,
                style: GoogleFonts.inter(
                  fontSize: 12,
                  fontWeight: FontWeight.w600,
                  color: color,
                ),
              ),
            ],
          ),
        ),
      ],
    );
  }
}

class _DownloadingView extends StatelessWidget {
  const _DownloadingView({required this.modelState});

  final AiModelSettingsState modelState;

  @override
  Widget build(BuildContext context) {
    final pct = (modelState.progress * 100).toStringAsFixed(1);

    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Expanded(
              child: Text(
                modelState.currentTask,
                style: GoogleFonts.inter(
                  fontSize: 13,
                  color: AppColors.textSecondary,
                ),
                maxLines: 1,
                overflow: TextOverflow.ellipsis,
              ),
            ),
            Text(
              '$pct %',
              style: GoogleFonts.inter(
                fontSize: 13,
                fontWeight: FontWeight.w600,
                color: AppColors.accent,
              ),
            ),
          ],
        ),
        const SizedBox(height: UIConstants.spacing8),
        ClipRRect(
          borderRadius: BorderRadius.circular(4),
          child: LinearProgressIndicator(
            value: modelState.progress,
            minHeight: 6,
            backgroundColor: AppColors.zinc800,
            valueColor:
                const AlwaysStoppedAnimation<Color>(AppColors.accent),
          ),
        ),
        if (modelState.errorMessage != null) ...[
          const SizedBox(height: UIConstants.spacing12),
          ErrorRow(message: modelState.errorMessage!),
        ],
      ],
    );
  }
}

class ErrorRow extends StatelessWidget {
  const ErrorRow({super.key, required this.message});

  final String message;

  @override
  Widget build(BuildContext context) {
    return Row(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        const Icon(
          Icons.error_outline_rounded,
          color: AppColors.destructive,
          size: 14,
        ),
        const SizedBox(width: UIConstants.spacing8),
        Expanded(
          child: Text(
            message,
            style: GoogleFonts.inter(
              fontSize: 12,
              color: AppColors.destructive,
              height: 1.4,
            ),
          ),
        ),
      ],
    );
  }
}