#!/usr/bin/env bash
#
# Simple FFmpeg CLI Toolset
# -------------------------
# Provides easy commands for single or multi-file video conversion.
# Works on Linux and Windows (Git Bash / WSL) as long as ffmpeg is installed.
#

set -euo pipefail

# ==========================================================
# Configuration system
# ==========================================================
CONFIG_FILE="$(dirname "$0")/config/config.json"

# -------------------------
# Default configuration
# -------------------------
OUTPUT_DIR="$HOME/Videos"
VIDEO_CODEC="libx264"
AUDIO_CODEC="aac"
CRF="18"                  # lower = higher quality
PRESET="slow"             # slower = better compression
AUDIO_BITRATE="192k"
VERSION="0.1.0"

# ==========================================================
# Utility: Colour logging
# ==========================================================
RED="\033[31m"
YELLOW="\033[33m"
GREEN="\033[32m"
BLUE="\033[34m"
NC="\033[0m"  # reset

info()    { echo -e "${BLUE}[INFO]${NC} $*"; }
success() { echo -e "${GREEN}[OK]${NC} $*"; }
warn()    { echo -e "${YELLOW}[WARN]${NC} $*"; }
error()   { echo -e "${RED}[ERROR]${NC} $*" >&2; }

# ==========================================================
# Check dependencies early
# ==========================================================
if ! command -v ffmpeg >/dev/null 2>&1; then
    error "ffmpeg is not installed or not in PATH."
    exit 1
fi

if [[ -f "$CONFIG_FILE" ]] && command -v jq >/dev/null 2>&1; then
    info "Loading configuration from: $CONFIG_FILE"
    OUTPUT_DIR="$(eval echo "$(jq -r '.output_dir // empty' "$CONFIG_FILE")")" || true
    VIDEO_CODEC="$(jq -r '.video_codec // empty' "$CONFIG_FILE" 2>/dev/null || echo "$VIDEO_CODEC")"
    AUDIO_CODEC="$(jq -r '.audio_codec // empty' "$CONFIG_FILE" 2>/dev/null || echo "$AUDIO_CODEC")"
    CRF="$(jq -r '.crf // empty' "$CONFIG_FILE" 2>/dev/null || echo "$CRF")"
    PRESET="$(jq -r '.preset // empty' "$CONFIG_FILE" 2>/dev/null || echo "$PRESET")"
    AUDIO_BITRATE="$(jq -r '.audio_bitrate // empty' "$CONFIG_FILE" 2>/dev/null || echo "$AUDIO_BITRATE")"
    VERSION="$(jq -r '.version // empty' "$CONFIG_FILE" 2>/dev/null || echo "$VERSION")"
elif [[ ! -f "$CONFIG_FILE" ]]; then
    warn "No config.json found — using internal defaults."
else
    warn "jq not found — skipping config.json parsing."
fi

mkdir -p "$OUTPUT_DIR" || { error "Failed to create output directory $OUTPUT_DIR"; exit 1; }

# ==========================================================
# Header output
# ==========================================================
print_header() {
    echo "----------------------------------------------"
    echo "Video Tools v$VERSION"
    echo "Output directory: $OUTPUT_DIR"
    echo "Video codec : $VIDEO_CODEC"
    echo "Audio codec : $AUDIO_CODEC"
    echo "CRF         : $CRF"
    echo "Preset      : $PRESET"
    echo "Audio rate  : $AUDIO_BITRATE"
    echo "----------------------------------------------"
}

# ==========================================================
# Convert one file
# ==========================================================
convert_single() {
    local input="$1"
    local output_name="$2"
    local output_path="$OUTPUT_DIR/$output_name"

    print_header
    info "Converting single video..."
    info "Input : $input"
    info "Output: $output_path"

    if [[ ! -f "$input" ]]; then
        error "Input file not found: $input"
        exit 1
    fi

    ffmpeg -hide_banner -loglevel info -fflags +genpts \
        -i "$input" \
        -c:v "$VIDEO_CODEC" -crf "$CRF" -preset "$PRESET" \
        -c:a "$AUDIO_CODEC" -b:a "$AUDIO_BITRATE" -movflags +faststart \
        "$output_path" || { error "Conversion failed."; exit 1; }

    success "Conversion complete: $output_path"
}

# ==========================================================
# Combine multiple files
# ==========================================================
convert_multiple() {
    local args=("$@")
    local output_name="${args[-1]}"
    unset 'args[-1]'
    local list_file
    list_file=$(mktemp)
    local output_path="$OUTPUT_DIR/$output_name"

    print_header
    info "Combining multiple videos..."
    for input in "${args[@]}"; do
        if [[ ! -f "$input" ]]; then
            error "Missing input file: $input"
            rm -f "$list_file"
            exit 1
        fi
        echo "file '$input'" >> "$list_file"
        info " + Added: $input"
    done
    echo "----------------------------------------------"

    ffmpeg -hide_banner -loglevel info -f concat -safe 0 -i "$list_file" \
        -c:v "$VIDEO_CODEC" -crf "$CRF" -preset "$PRESET" \
        -c:a "$AUDIO_CODEC" -b:a "$AUDIO_BITRATE" -movflags +faststart \
        "$output_path" || { error "Merge failed."; rm -f "$list_file"; exit 1; }

    rm -f "$list_file"
    success "Combined video created: $output_path"
}

# ==========================================================
# Dispatcher
# ==========================================================
case "${1:-}" in
    convert-single)
        shift
        if [[ $# -ne 2 ]]; then
            error "Usage: $0 convert-single <input> <output.mp4>"
            exit 1
        fi
        convert_single "$@"
        ;;
    convert-multiple)
        shift
        if [[ $# -lt 3 ]]; then
            error "Usage: $0 convert-multiple <input1> <input2> ... <output.mp4>"
            exit 1
        fi
        convert_multiple "$@"
        ;;
    *)
        echo "Video Tools v$VERSION"
        echo "Usage:"
        echo "  $0 convert-single <input> <output.mp4>"
        echo "  $0 convert-multiple <input1> <input2> ... <output.mp4>"
        echo ""
        echo "All outputs will be saved in: $OUTPUT_DIR"
        ;;
esac