#!/bin/bash

################################################################################
# Plex Database Query Script
################################################################################
#
# Author: Peter Wood <peter@peterwood.dev>
# Description: Flexible Plex Media Server database query tool supporting
#              multiple query types including recent additions, library stats,
#              media counts, and custom queries.
#
# Features:
#   - Multiple query types (recent, stats, count, libraries, custom)
#   - Recent additions reporting (configurable time range)
#   - Library section filtering and statistics
#   - Formatted output with headers and columns
#   - Direct SQLite database querying
#   - Media type categorization
#   - Custom SQL query execution
#
# Related Scripts:
#   - backup-plex.sh: Backs up the database queried by this script
#   - plex.sh: General Plex service management
#   - validate-plex-backups.sh: Validates database integrity
#   - monitor-plex-backup.sh: System monitoring
#
# Usage:
#   ./plex-recent-additions.sh [QUERY_TYPE] [OPTIONS]
#   
#   Query Types:
#     recent [DAYS]     # Show additions from last N days (default: 7)
#     stats             # Show library statistics
#     count             # Show media counts by library
#     libraries         # List all libraries
#     custom "SQL"      # Execute custom SQL query
#
# Examples:
#   ./plex-recent-additions.sh recent        # Last 7 days additions
#   ./plex-recent-additions.sh recent 30     # Last 30 days additions
#   ./plex-recent-additions.sh stats         # Library statistics
#   ./plex-recent-additions.sh count         # Media counts
#   ./plex-recent-additions.sh libraries     # List libraries
#   ./plex-recent-additions.sh custom "SELECT name FROM library_sections"
#
# Dependencies:
#   - sqlite3 (for database queries)
#   - Plex Media Server with populated library
#   - Read access to Plex database files
#
# Exit Codes:
#   0 - Success
#   1 - Database not found or access denied
#   2 - Query execution failure
#   3 - Invalid arguments
#
################################################################################

# Configuration
PLEX_SQLITE="/usr/lib/plexmediaserver/Plex SQLite"
PLEX_DB="/var/lib/plexmediaserver/Library/Application Support/Plex Media Server/Plug-in Support/Databases/com.plexapp.plugins.library.db"

################################################################################
# Core Functions
################################################################################

# Execute SQL query with formatted output
execute_query() {
    local query="$1"
    local description="$2"
    
    if [ -n "$description" ]; then
        echo "=== $description ==="
        echo
    fi
    
    if ! "$PLEX_SQLITE" "$PLEX_DB" <<EOF
.headers on
.mode column
$query
EOF
    then
        echo "Error: Query execution failed" >&2
        return 2
    fi
    
    echo
}

# Validate database access
check_database() {
    if [ ! -f "$PLEX_DB" ]; then
        echo "Error: Plex database not found at $PLEX_DB" >&2
        exit 1
    fi
    
    if [ ! -r "$PLEX_DB" ]; then
        echo "Error: Cannot read Plex database at $PLEX_DB" >&2
        exit 1
    fi
}

################################################################################
# Query Functions
################################################################################

# Recent additions query
query_recent_additions() {
    local days=${1:-7}
    
    # Validate that days is a number
    if ! [[ "$days" =~ ^[0-9]+$ ]]; then
        echo "Error: DAYS must be a positive integer" >&2
        return 3
    fi
    
    # Count query
    local count_query="
SELECT
    count(meta.library_section_id) as \"Count\"
FROM
    metadata_items meta
    join library_sections lib on meta.library_section_id = lib.id
WHERE
    meta.added_at >= strftime('%s', 'now', '-$days days')
    and meta.year is not null 
    and meta.title is not null;"
    
    execute_query "$count_query" "Total Recent Additions (Last $days days)"
    
    # Detail query
    local detail_query="
SELECT
    date(meta.added_at, 'unixepoch', 'localtime') AS \"added_at\",
    trim(lib.name) as \"library_name\",
    meta.year,
    trim(meta.title) as \"title\"
FROM
    metadata_items meta
    join library_sections lib on meta.library_section_id = lib.id
WHERE
    meta.added_at >= strftime('%s', 'now', '-$days days')
    and meta.year is not null 
    and meta.title is not null
ORDER BY lib.name, meta.added_at DESC;"
    
    execute_query "$detail_query" "Recent Additions Details (Last $days days)"
}

# Library statistics query
query_library_stats() {
    local stats_query="
SELECT 
    lib.name as \"Library\",
    COUNT(meta.id) as \"Total Items\",
    COUNT(CASE WHEN meta.added_at >= strftime('%s', 'now', '-7 days') THEN 1 END) as \"Added Last 7 Days\",
    COUNT(CASE WHEN meta.added_at >= strftime('%s', 'now', '-30 days') THEN 1 END) as \"Added Last 30 Days\",
    date(MIN(meta.added_at), 'unixepoch', 'localtime') as \"Oldest Addition\",
    date(MAX(meta.added_at), 'unixepoch', 'localtime') as \"Latest Addition\"
FROM 
    library_sections lib
    LEFT JOIN metadata_items meta ON lib.id = meta.library_section_id
WHERE 
    meta.metadata_type IN (1, 2, 4) -- Movies, Shows, Episodes
    AND meta.title IS NOT NULL
GROUP BY 
    lib.id, lib.name
ORDER BY 
    lib.name;"
    
    execute_query "$stats_query" "Library Statistics"
}

# Media count by library
query_media_counts() {
    local count_query="
SELECT 
    lib.name as \"Library\",
    CASE 
        WHEN meta.metadata_type = 1 THEN 'Movie'
        WHEN meta.metadata_type = 2 THEN 'TV Show'
        WHEN meta.metadata_type = 4 THEN 'Episode'
        WHEN meta.metadata_type = 9 THEN 'Album'
        WHEN meta.metadata_type = 10 THEN 'Track'
        ELSE 'Other'
    END as \"Media Type\",
    COUNT(*) as \"Count\"
FROM 
    library_sections lib
    LEFT JOIN metadata_items meta ON lib.id = meta.library_section_id
WHERE 
    meta.title IS NOT NULL
GROUP BY 
    lib.name, meta.metadata_type
ORDER BY 
    lib.name, meta.metadata_type;"
    
    execute_query "$count_query" "Media Counts by Library and Type"
}

# List all libraries
query_libraries() {
    local libraries_query="
SELECT 
    lib.id as \"ID\",
    lib.name as \"Library Name\",
    lib.section_type as \"Type\",
    COUNT(meta.id) as \"Items\"
FROM 
    library_sections lib
    LEFT JOIN metadata_items meta ON lib.id = meta.library_section_id
GROUP BY 
    lib.id, lib.name, lib.section_type
ORDER BY 
    lib.name;"
    
    execute_query "$libraries_query" "All Libraries"
}

# Execute custom query
query_custom() {
    local custom_sql="$1"
    
    if [ -z "$custom_sql" ]; then
        echo "Error: Custom SQL query cannot be empty" >&2
        return 3
    fi
    
    execute_query "$custom_sql" "Custom Query"
}

################################################################################
# Help and Usage
################################################################################

show_help() {
    echo "Usage: $0 [QUERY_TYPE] [OPTIONS]"
    echo
    echo "Query Types:"
    echo "  recent [DAYS]     Show additions from last N days (default: 7)"
    echo "  stats             Show library statistics"
    echo "  count             Show media counts by library"
    echo "  libraries         List all libraries"
    echo "  custom \"SQL\"      Execute custom SQL query"
    echo
    echo "Examples:"
    echo "  $0 recent         # Last 7 days additions"
    echo "  $0 recent 30      # Last 30 days additions"
    echo "  $0 stats          # Library statistics"
    echo "  $0 count          # Media counts"
    echo "  $0 libraries      # List libraries"
    echo "  $0 custom \"SELECT COUNT(*) FROM metadata_items\""
    echo
    echo "Options:"
    echo "  --help, -h        Show this help message"
    echo
    echo "Exit Codes:"
    echo "  0 - Success"
    echo "  1 - Database not found or access denied"
    echo "  2 - Query execution failure"
    echo "  3 - Invalid arguments"
}

################################################################################
# Main Script Logic
################################################################################

# Check database access first
check_database

# Handle command line arguments
case "${1:-recent}" in
    "recent"|"additions")
        query_recent_additions "${2:-7}"
        ;;
    "stats"|"statistics")
        query_library_stats
        ;;
    "count"|"counts")
        query_media_counts
        ;;
    "libraries"|"libs")
        query_libraries
        ;;
    "custom")
        if [ -z "$2" ]; then
            echo "Error: Custom query requires SQL as second argument" >&2
            echo "Usage: $0 custom \"SELECT * FROM library_sections\"" >&2
            exit 3
        fi
        query_custom "$2"
        ;;
    "--help"|"-h"|"help")
        show_help
        exit 0
        ;;
    *)
        # Backward compatibility: if first arg is a number, treat as recent query
        if [[ "$1" =~ ^[0-9]+$ ]]; then
            query_recent_additions "$1"
        else
            echo "Error: Unknown query type '$1'" >&2
            echo "Use --help for usage information" >&2
            exit 3
        fi
        ;;
esac