use async_trait::async_trait;
use cm_dashboard_shared::{AgentData, BackupData, BackupDiskData};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::fs;
use std::path::Path;
use tracing::debug;

use super::{Collector, CollectorError};

/// Backup collector that reads backup status from TOML files with structured data output
pub struct BackupCollector {
    /// Path to backup status file
    status_file_path: String,
}

impl BackupCollector {
    pub fn new() -> Self {
        Self {
            status_file_path: "/var/lib/backup/backup-status.toml".to_string(),
        }
    }

    /// Read backup status from TOML file
    async fn read_backup_status(&self) -> Result<Option<BackupStatusToml>, CollectorError> {
        if !Path::new(&self.status_file_path).exists() {
            debug!("Backup status file not found: {}", self.status_file_path);
            return Ok(None);
        }

        let content = fs::read_to_string(&self.status_file_path)
            .map_err(|e| CollectorError::SystemRead {
                path: self.status_file_path.clone(),
                error: e.to_string(),
            })?;

        let status: BackupStatusToml = toml::from_str(&content)
            .map_err(|e| CollectorError::Parse {
                value: content.clone(),
                error: format!("Failed to parse backup status TOML: {}", e),
            })?;

        Ok(Some(status))
    }

    /// Convert BackupStatusToml to BackupData and populate AgentData
    async fn populate_backup_data(&self, agent_data: &mut AgentData) -> Result<(), CollectorError> {
        if let Some(backup_status) = self.read_backup_status().await? {
            // Use raw start_time string from TOML

            // Extract disk information
            let repository_disk = if let Some(disk_space) = &backup_status.disk_space {
                Some(BackupDiskData {
                    serial: backup_status.disk_serial_number.clone().unwrap_or_else(|| "Unknown".to_string()),
                    usage_percent: disk_space.usage_percent as f32,
                    used_gb: disk_space.used_gb as f32,
                    total_gb: disk_space.total_gb as f32,
                    wear_percent: backup_status.disk_wear_percent,
                    temperature_celsius: None, // Not available in current TOML
                })
            } else if let Some(serial) = &backup_status.disk_serial_number {
                // Fallback: create minimal disk info if we have serial but no disk_space
                Some(BackupDiskData {
                    serial: serial.clone(),
                    usage_percent: 0.0,
                    used_gb: 0.0,
                    total_gb: 0.0,
                    wear_percent: backup_status.disk_wear_percent,
                    temperature_celsius: None,
                })
            } else {
                None
            };

            // Calculate total repository size from services
            let total_size_gb = backup_status.services
                .values()
                .map(|service| service.repo_size_bytes as f32 / (1024.0 * 1024.0 * 1024.0))
                .sum::<f32>();

            let backup_data = BackupData {
                status: backup_status.status,
                total_size_gb: Some(total_size_gb),
                repository_health: Some("ok".to_string()), // Derive from status if needed
                repository_disk,
                last_backup_size_gb: None, // Not available in current TOML format
                start_time_raw: Some(backup_status.start_time),
            };

            agent_data.backup = backup_data;
        } else {
            // No backup status available - set default values
            agent_data.backup = BackupData {
                status: "unavailable".to_string(),
                total_size_gb: None,
                repository_health: None,
                repository_disk: None,
                last_backup_size_gb: None,
                start_time_raw: None,
            };
        }

        Ok(())
    }
}

#[async_trait]
impl Collector for BackupCollector {
    async fn collect_structured(&self, agent_data: &mut AgentData) -> Result<(), CollectorError> {
        debug!("Collecting backup status");
        self.populate_backup_data(agent_data).await
    }
}

/// TOML structure for backup status file
#[derive(Debug, Clone, Serialize, Deserialize)]
struct BackupStatusToml {
    pub backup_name: String,
    pub start_time: String,
    pub current_time: String,
    pub duration_seconds: i64,
    pub status: String,
    pub last_updated: String,
    pub disk_space: Option<DiskSpace>,
    pub disk_product_name: Option<String>,
    pub disk_serial_number: Option<String>,
    pub disk_wear_percent: Option<f32>,
    pub services: HashMap<String, ServiceStatus>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
struct DiskSpace {
    pub total_bytes: u64,
    pub used_bytes: u64,
    pub available_bytes: u64,
    pub total_gb: f64,
    pub used_gb: f64,
    pub available_gb: f64,
    pub usage_percent: f64,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
struct ServiceStatus {
    pub status: String,
    pub exit_code: i64,
    pub repo_path: String,
    pub archive_count: i64,
    pub repo_size_bytes: u64,
}