#!/bin/bash
# MTP v1.2 - Media Tail Player
# Play .part files while downloading, recording or generating TTS
# r = refresh (resume with more buffer)
# q = quit (saves position)

G='\033[1;32m'
Y='\033[1;33m'
C='\033[1;36m'
M='\033[1;35m'
R='\033[0m'

WATCH_LATER_BASE="$HOME/.config/mpv/watch_later"
mkdir -p "$WATCH_LATER_BASE"

# === FUNCTIONS ===

_session_dir() {
    local file="$1"
    # Use only basename so files in different dirs share the same session
    # e.g. party/file.m4a.part and oh/file.m4a -> same session dir
    # Remove '/' completely to avoid creating unintended subdirectories
    # e.g. "80/20 Principle" -> "8020_Principle" not "80/20_Principle"
    local base
    base=$(basename "${file%.part}")
    local stem="${base%.*}"
    local safe
    safe=$(echo "$stem" | tr -d '/' | tr ' ' '_')
    echo "$WATCH_LATER_BASE/sessions/${safe}"
}

_wait_for_min_size() {
    local file="$1"
    [[ "$file" != *.part ]] && return 0

    local size
    size=$(stat -c%s "$file" 2>/dev/null || stat -f%z "$file" 2>/dev/null)
    if (( size < 1048576 )); then
        echo -e "${Y}⏳ Waiting for minimum size: 1 MB${R}"
        while (( size < 1048576 )); do
            sleep 1
            size=$(stat -c%s "$file" 2>/dev/null || stat -f%z "$file" 2>/dev/null)
            local size_mb
            size_mb=$(echo "scale=2; $size / 1048576" | bc)
            echo -ne "\r${M}📊 Size: ${size_mb} MB  ${R}"
        done
        local size_mb
        size_mb=$(echo "scale=2; $size / 1048576" | bc)
        echo -e "\n${G}✅ Minimum size reached: ${size_mb} MB${R}"
    fi
}

_create_input_conf() {
    local conf="$1"
    cat > "$conf" <<'EOF'
SPACE cycle pause
9 add volume -5
0 add volume +5
, seek -10 relative+keyframes
. seek +10 relative+keyframes
LEFT seek -20 relative+keyframes
RIGHT seek +20 relative+keyframes
UP seek +120 relative+keyframes
DOWN seek -120 relative+keyframes
HOME seek 0 absolute
r seek 0 absolute
o show-text "Buffer: ${demuxer-cache-duration}s | ${demuxer-cache-time}s cached" 5000
e quit 3
u quit 42
q quit 4
EOF
}

_show_file_info() {
    local file="$1"
    local size_mb
    size_mb=$(echo "scale=2; $(stat -c%s "$file" 2>/dev/null || stat -f%z "$file" 2>/dev/null) / 1048576" | bc)
    local session_dir
    session_dir=$(_session_dir "$file")

    echo -e "${C}____________________________________________________________${R}"
    echo -e "${C}  MTP v1.2 | MEDIA TAIL PLAYER                            ${R}"
    echo -e "${C}____________________________________________________________${R}"
    echo -e "${Y}  9 / 0  : Volume down / up              ${R}"
    echo -e "${Y}  , / .  : Seek -10 / +10 sec            ${R}"
    echo -e "${Y}  ← / →  : Seek -20 / +20 sec            ${R}"
    echo -e "${Y}  ↑ / ↓  : Seek +120 / -120 sec          ${R}"
    echo -e "${Y}  SPACE  : Pause / Resume                 ${R}"
    echo -e "${Y}  r/HOME : Restart |  u: Refresh         ${R}"
    echo -e "${Y}  q      : Quit    |  o: OSD             ${R}"
    echo -e "${Y}  e      : EOF menu                      ${R}"
    echo -e "${C}____________________________________________________________${R}"
    if [[ "$file" == *.part ]]; then
        echo -e "${Y}📥 Downloading (.part)${R}"
    else
        echo -e "${G}✅ Ready${R}"
    fi
    echo -e "${G}🎵 File:${R} $(basename "$file")"
    echo -e "${M}📊 Size:${R} ${size_mb} MB"

    local saved_pos
    saved_pos=$(_get_saved_pos "$session_dir")
    if [[ -n "$saved_pos" ]]; then
        local min sec
        min=$(echo "scale=0; $saved_pos / 60" | bc 2>/dev/null || echo "0")
        sec=$(printf "%.0f" "$(echo "$saved_pos % 60" | bc 2>/dev/null)" 2>/dev/null || echo "0")
        echo -e "${G}💾 Resuming from:${R} ${min}m ${sec}s"
    fi
    echo -e "${C}____________________________________________________________${R}"
}

_get_saved_pos() {
    local session_dir="$1"
    local pos_file="$session_dir/position.txt"
    if [[ -f "$pos_file" ]]; then
        cat "$pos_file"
    fi
}

_save_pos_from_session() {
    # Read start= from any mpv watch_later file in session_dir and save to position.txt
    local session_dir="$1"
    local pos_file="$session_dir/position.txt"
    local saved
    saved=$(find "$session_dir" -type f ! -name "position.txt" 2>/dev/null \
            | xargs grep -h "^start=" 2>/dev/null | tail -1 | cut -d'=' -f2)
    if [[ -n "$saved" ]]; then
        echo "$saved" > "$pos_file"
    fi
}

_run_mpv() {
    local file="$1"
    local session_dir
    session_dir=$(_session_dir "$file")
    mkdir -p "$session_dir"

    local input_conf
    input_conf=$(mktemp)
    trap "rm -f '$input_conf'" RETURN
    _create_input_conf "$input_conf"

    local size_at_start
    size_at_start=$(stat -c%s "$file" 2>/dev/null || stat -f%z "$file" 2>/dev/null)

    local keep_open="no"
    [[ "$file" == *.part ]] && keep_open="yes"

    # Read saved position from our own position.txt (works across .part -> .m4a switch)
    local start_param=""
    local saved_pos
    saved_pos=$(_get_saved_pos "$session_dir")
    if [[ -n "$saved_pos" ]]; then
        start_param="--start=${saved_pos}"
    fi

    local _MC=$'\033[1;36m'
    local _MR=$'\033[0m'

    mpv \
        --volume=70 \
        --keep-open="$keep_open" \
        --no-input-default-bindings \
        --input-conf="$input_conf" \
        --demuxer-lavf-o=fflags=+nobuffer+fastseek \
        --demuxer-readahead-secs=1 \
        --cache=yes \
        --cache-secs=10 \
        --demuxer-max-bytes=50M \
        --demuxer-max-back-bytes=20M \
        --stream-buffer-size=2M \
        --hr-seek=yes \
        --hr-seek-demuxer-offset=0 \
        --save-position-on-quit \
        --watch-later-directory="$session_dir" \
        --title="MTP: $(basename "$file")" \
        --term-status-msg='${time-pos}/${duration} | V:${volume}%' \
        --term-playing-msg="${_MC}▶ \${filename}${_MR}" \
        $start_param \
        "$file"

    local exit_code=$?

    # After mpv exits, read its watch_later file and save position to our position.txt
    # This works regardless of which hash mpv used internally
    _save_pos_from_session "$session_dir"

    local size_after size_at_start_mb size_after_mb
    size_after=$(stat -c%s "$file" 2>/dev/null || stat -f%z "$file" 2>/dev/null || echo "$size_at_start")
    size_at_start_mb=$(echo "scale=2; $size_at_start / 1048576" | bc)
    size_after_mb=$(echo "scale=2; $size_after / 1048576" | bc)
    local size_diff=$(( size_after - size_at_start ))

    echo ""
    echo -e "${C}____________________________________________________________${R}"
    echo -e "${M}📊 Size at start:${R} ${size_at_start_mb} MB"
    echo -e "${M}📊 Size at end:${R}   ${size_after_mb} MB"
    if (( size_diff > 0 )); then
        local size_diff_mb
        size_diff_mb=$(echo "scale=2; $size_diff / 1048576" | bc)
        echo -e "${G}📈 Downloaded during playback:${R} +${size_diff_mb} MB"
    fi
    echo -e "${C}____________________________________________________________${R}"

    return $exit_code
}

_find_base_file() {
    local part_file="$1"
    local base="${part_file%.part}"

    if [[ -f "$base" ]]; then
        echo "$base"
        return 0
    fi

    local stem="${base%.*}"
    local found
    found=$(ls -t "${stem}".mp4 "${stem}".mkv "${stem}".webm \
               "${stem}".m4a "${stem}".mp3 "${stem}".opus \
               "${stem}".ogg "${stem}".flac "${stem}".wav 2>/dev/null | head -1)
    echo "$found"
}

# Auto-switch from .part to completed file if download finished
_check_and_switch() {
    local file="$1"
    [[ "$file" != *.part ]] && echo "$file" && return 0

    local base
    base=$(_find_base_file "$file")
    if [[ -n "$base" ]]; then
        echo -e "${G}✨ Download complete — switching to: $(basename "$base")${R}" >&2
        echo "$base"
    else
        echo "$file"
    fi
}

# === FILE SELECTION ===
if [[ -n "$1" ]]; then
    CURRENT_FILE="$1"
    if [[ ! -f "$CURRENT_FILE" ]]; then
        echo -e "${Y}❌ File not found: $CURRENT_FILE${R}"
        exit 1
    fi
    echo -e "${C}📂 File selected from argument${R}"
else
    CURRENT_FILE=$(ls -t *.part 2>/dev/null | head -1)
    if [[ -z "$CURRENT_FILE" ]]; then
        CURRENT_FILE=$(ls -t *.mp4 *.mkv *.webm *.avi *.mp3 *.opus \
                          *.ogg *.m4a *.flac *.wav 2>/dev/null | head -1)
    fi
    if [[ -z "$CURRENT_FILE" ]]; then
        echo -e "${Y}❌ No media files found${R}"
        exit 1
    fi
    echo -e "${C}📂 Auto-selected latest file${R}"
fi

# === MAIN LOOP ===
while true; do
    _wait_for_min_size "$CURRENT_FILE"
    _show_file_info "$CURRENT_FILE"
    _run_mpv "$CURRENT_FILE"
    EXIT_CODE=$?

    if [[ $EXIT_CODE -eq 42 ]]; then
        # u pressed - refresh
        echo -e "${G}🔄 Refreshing...${R}"
        CURRENT_FILE=$(_check_and_switch "$CURRENT_FILE")
        if [[ "$CURRENT_FILE" == *.part ]]; then
            local_size=$(stat -c%s "$CURRENT_FILE" 2>/dev/null || stat -f%z "$CURRENT_FILE" 2>/dev/null)
            local_mb=$(echo "scale=2; $local_size / 1048576" | bc)
            echo -e "${M}📊 Current .part size: ${local_mb} MB${R}"
        else
            echo -e "${G}✅ Resuming from saved position...${R}"
        fi
        sleep 1
        continue

    elif [[ $EXIT_CODE -eq 4 ]]; then
        # q pressed - exit immediately
        break

    elif [[ $EXIT_CODE -eq 3 || $EXIT_CODE -eq 0 ]]; then
        # e pressed or natural EOF - check for completed file first
        CURRENT_FILE=$(_check_and_switch "$CURRENT_FILE")

        echo -e "${G}✅ Playback paused at end of buffer (EOF)${R}"
        echo -e "${C}____________________________________________________________${R}"
        echo -e "${Y}  u / SPACE : Check for more data & Resume${R}"
        echo -e "${Y}  r / HOME  : Restart file${R}"
        echo -e "${Y}  q / Enter : Quit${R}"
        echo -e "${C}____________________________________________________________${R}"

        read -r -s -n 1 choice
        # Handle escape sequences (arrow keys, HOME, etc.)
        if [[ "$choice" == $'\033' ]]; then
            read -r -s -n 2 -t 0.1 seq
            choice="${choice}${seq}"
        fi
        if [[ "$choice" == "u" || "$choice" == "U" || "$choice" == " " ]]; then
            echo -e "${G}🔄 Resuming from last saved position...${R}"
            sleep 1
            continue
        elif [[ "$choice" == "r" || "$choice" == "R" || "$choice" == $'\033[H' || "$choice" == $'\033OH' ]]; then
            session=$(_session_dir "$CURRENT_FILE")
            find "$session" -type f -delete 2>/dev/null
            echo -e "${G}⏮  Restarting file...${R}"
            sleep 1
            continue
        else
            break
        fi

    else
        break
    fi
done