#!/bin/bash

# Configuration
backupPath='/mnt/backups'
password_file="/etc/restic-password"
LOG_DIR="$HOME/mb-backups/logs"
LOG_FILE="${LOG_DIR}/restic_snapshot.log"
ERROR_LOG_FILE="${LOG_DIR}/restic_snapshot_error.log"

# Ensure log directory exists
mkdir -p "$LOG_DIR"

# Logging function
log_message() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] $1" | tee -a "$LOG_FILE"
}

# Error logging function
log_error() {
    echo "[$(date +'%Y-%m-%d %H:%M:%S')] ERROR: $1" | tee -a "$ERROR_LOG_FILE"
}

# Function: Display usage and tags
display_usage() {
    local tags
    tags=$(fetch_available_tags)
    echo "Usage: $0 <tag>"
    echo "Available tags:"
    if [ -z "$tags" ]; then
        echo "  (No tags found or repository inaccessible)"
    else
        echo "  all"
        echo "$tags" | sed 's/^/  /'
    fi
    exit 1
}

# Function: Fetch available tags
fetch_available_tags() {
    log_message "Fetching available tags..."
    local snapshot_json

    # Retrieve JSON snapshot data
    snapshot_json=$(RESTIC_PASSWORD=$(cat "$password_file") restic -r "$backupPath" snapshots --json 2>/dev/null)
    if [ $? -ne 0 ]; then
        log_error "Failed to retrieve snapshots. Check repository path or password."
        return 1
    fi

    # Extract unique tags from JSON data
    local tags
    tags=$(echo "$snapshot_json" | jq -r '.[].tags[]' 2>/dev/null | sort -u | uniq)
    if [ -z "$tags" ]; then
        log_message "No tags found in repository snapshots."
    fi

    echo "$tags"
    return 0
}

# Function: Validate repository access
# Function: Validate repository access
validate_repository() {
    log_message "Validating repository access..."

    # Check if repository path exists
    if [ ! -d "$backupPath" ]; then
        log_error "Backup path '$backupPath' does not exist or is not accessible."
        echo "Restic repository path not found. Please verify that the path exists and is mounted."
        exit 1
    fi

    # Check if Restic can access the repository
    if ! RESTIC_PASSWORD=$(cat "$password_file") restic -r "$backupPath" snapshots &>/dev/null; then
        # Attempt to fix permissions automatically
        log_message "Attempting to fix permissions for '$backupPath'..."
        sudo chown -R $(whoami):$(whoami) "$backupPath"
        sudo chmod -R u+rw "$backupPath"

        # Retry repository validation
        if ! RESTIC_PASSWORD=$(cat "$password_file") restic -r "$backupPath" snapshots &>/dev/null; then
            log_error "Unable to access Restic repository at '$backupPath'."
            echo "Restic repository is inaccessible. Please check the path, permissions, or mount status."
            exit 1
        fi
    fi

    log_message "Repository access validated successfully."
}

# Function: Fix permissions if necessary
fix_permissions() {
    log_message "Checking permissions for '$backupPath'..."
    if [ ! -r "$backupPath" ] || [ ! -w "$backupPath" ]; then
        log_message "Fixing permissions for '$backupPath'..."
        sudo chown -R $(whoami):$(whoami) "$backupPath"
        sudo chmod -R u+rw "$backupPath"
    fi
}

# Function: Display all snapshots
display_all_snapshots() {
    log_message "Retrieving all snapshots..."
    if RESTIC_PASSWORD=$(cat "$password_file") restic -r "$backupPath" snapshots --json | jq -r '.[] | "\(.short_id) \(.time) \(.tags | join(", "))"' 2>/dev/null; then
        log_message "All snapshots displayed successfully."
    else
        log_error "Unable to retrieve all snapshots."
        exit 1
    fi
}

# Function: Validate environment
validate_environment() {
    if [ ! -f "$password_file" ]; then
        log_error "Password file not found at $password_file"
        exit 1
    fi

    if [ ! -d "$backupPath" ]; then
        log_error "Backup path '$backupPath' does not exist or is not accessible."
        exit 1
    fi

    validate_repository
    fix_permissions
}

# Main script logic
main() {
    # If no arguments are provided, display usage
    if [ "$#" -eq 0 ]; then
        display_usage
    fi

    # Assign input argument
    TAG=$1

    # Validate environment and dependencies
    validate_environment

    # Handle the special case for "all"
    if [ "$TAG" == "all" ]; then
        display_all_snapshots
        exit 0
    fi

    # Validate the tag
    log_message "Validating tag '$TAG'..."
    local available_tags
    available_tags=$(fetch_available_tags)
    if ! echo "$available_tags" | grep -qw "$TAG"; then
        log_error "Unknown or unused tag '$TAG'."
        display_usage
    fi

    # Display snapshots for the provided tag
    log_message "Retrieving snapshots for tag '$TAG'..."
    if RESTIC_PASSWORD=$(cat "$password_file") restic -r "$backupPath" snapshots --tag "$TAG" --json | jq -r '.[] | "\(.short_id) \(.time) \(.tags | join(", "))"' 2>/dev/null; then
        log_message "Snapshots for tag '$TAG' displayed successfully."
    else
        log_error "Unable to display snapshots for tag '$TAG'."
        exit 1
    fi
}

# Run main function
main "$@"