import mido
from .midi_utils import get_instrument_name, has_musical_messages, collect_tempo_changes


def analyze_midi(midi: mido.MidiFile, filename: str = "") -> dict:
    analysis = {
        "song_title": filename,
        "tempo": {
            "min_bpm": None,
            "max_bpm": None
        },
        "pitch_bend": {
            "min_semitones": None,
            "max_semitones": None
        },
        "tracks": [],
        "notes": "",
        "song_offset": 0
    }

    tempo_changes = collect_tempo_changes(midi)
    tempos = [bpm for (_, bpm) in tempo_changes]
    analysis["tempo"]["min_bpm"] = min(tempos)
    analysis["tempo"]["max_bpm"] = max(tempos)

    musical_track_count = 0
    channel_rpn_state = {channel: {'selected_rpn_msb': None, 'selected_rpn_lsb': None, 'rpn_selected': None} for channel in range(16)}
    channel_pitch_bend_range = {channel: 2 for channel in range(16)}

    global_pitch_bends = []

    for track in midi.tracks:
        if not has_musical_messages(track):
            continue

        musical_track_count += 1
        track_info = {
            "track_name": f"Track {musical_track_count}",
            "Channel Assignment": [],
            "Pitch Bend Sensitivity": {},
            "Max Note Velocity": "N/A",
            "Min Note Velocity": "N/A",
            "Uses Program Change": False
        }

        program_changes = []
        pitch_bends_semitones = []
        absolute_time = 0

        for msg in track:
            absolute_time += msg.time
            if msg.type == 'track_name':
                track_info["track_name"] = msg.name
            elif hasattr(msg, 'channel'):
                channel = msg.channel
                if (channel + 1) not in track_info["Channel Assignment"]:
                    track_info["Channel Assignment"].append(channel + 1)

                if msg.type == 'note_on' and msg.velocity > 0:
                    velocity = msg.velocity
                    if track_info["Max Note Velocity"] == "N/A" or velocity > track_info["Max Note Velocity"]:
                        track_info["Max Note Velocity"] = velocity
                    if track_info["Min Note Velocity"] == "N/A" or velocity < track_info["Min Note Velocity"]:
                        track_info["Min Note Velocity"] = velocity
                elif msg.type == 'program_change':
                    track_info["Uses Program Change"] = True
                    program_changes.append({
                        "program_number": msg.program,
                        "instrument_name": get_instrument_name(msg.program),
                        "tick": absolute_time
                    })
                elif msg.type == 'control_change':
                    if msg.control == 101:
                        channel_rpn_state[channel]['selected_rpn_msb'] = msg.value
                        if msg.value != 0:
                            channel_rpn_state[channel]['rpn_selected'] = None
                    elif msg.control == 100:
                        channel_rpn_state[channel]['selected_rpn_lsb'] = msg.value
                        if (channel_rpn_state[channel]['selected_rpn_msb'] == 0 and
                            channel_rpn_state[channel]['selected_rpn_lsb'] == 0):
                            channel_rpn_state[channel]['rpn_selected'] = 'pitch_bend_range'
                        else:
                            channel_rpn_state[channel]['rpn_selected'] = None
                    elif msg.control == 6:
                        if channel_rpn_state[channel].get('rpn_selected') == 'pitch_bend_range':
                            channel_pitch_bend_range[channel] = msg.value
                    elif msg.control == 38:
                        pass
                elif msg.type == 'pitchwheel':
                    current_range = channel_pitch_bend_range[channel]
                    semitones = (msg.pitch / 8192) * current_range
                    pitch_bends_semitones.append(semitones)
                    global_pitch_bends.append(semitones)

        for channel in track_info["Channel Assignment"]:
            sensitivity = channel_pitch_bend_range[channel - 1]
            track_info["Pitch Bend Sensitivity"][f"Channel {channel}"] = round(sensitivity, 2)

        if pitch_bends_semitones:
            track_info["pitch_bend"] = {
                "min_semitones": round(min(pitch_bends_semitones), 2),
                "max_semitones": round(max(pitch_bends_semitones), 2)
            }
        else:
            track_info["pitch_bend"] = {
                "min_semitones": 0.0,
                "max_semitones": 0.0
            }

        if program_changes:
            track_info["Program Changes"] = program_changes

        analysis["tracks"].append(track_info)

    if global_pitch_bends:
        analysis["pitch_bend"]["min_semitones"] = round(min(global_pitch_bends), 2)
        analysis["pitch_bend"]["max_semitones"] = round(max(global_pitch_bends), 2)
    else:
        analysis["pitch_bend"]["min_semitones"] = 0.0
        analysis["pitch_bend"]["max_semitones"] = 0.0

    return analysis