from os import SCHED_OTHER
from django.conf import settings
from django.db import models
from django.utils.text import slugify
from django.utils.timezone import now
from django.utils.functional import cached_property
from django.core.files.storage import get_storage_class
from django.db.models import Q

import re

import logging
logger = logging.getLogger(__name__)

try:
    library_storage = get_storage_class(settings.LIBRARY_STORAGE)()
except (ImportError, AttributeError):
    library_storage = get_storage_class()()
logger.info("Library storage: %s", library_storage.__class__.__name__)

# taken from https://imslp.org/wiki/IMSLP:Abbreviations_for_Instruments
ABBREVIATIONS = """
score   Score
acc 	Accordion 
afl 	Alto flute 
alt 	Alto (voice) (contralto) 
arp 	Arpeggione 
bag 	Bagpipe 
bar 	Baritone (voice) 
bass 	Bass (voice) 
bbar 	Bass baritone (voice) 
bc 	    Continuo (Basso continuo) 
bcl 	Bass clarinet 
bell 	Bell (Chimes) 
bfl 	Bass flute 
bgtr 	Bass guitar 
bjo 	Banjo 
bn 	    Bassoon 
bob 	Bass oboe (Baritone oboe) 
br 	    Brass instruments 
bryt 	Baryton 
bstcl 	Basset clarinet 
bsthn 	Basset horn 
bug 	Bugle 
cbcl 	Contrabass clarinet 
cbn 	Contrabassoon 
cch 	Children's chorus 
cel 	Celesta 
ch 	    Mixed chorus 
cimb 	Cimbalom 
cit 	Cittern 
cl 	    Clarinet 
clvd 	Clavichord 
cm 	    Chalumeau 
conc 	Concertina 
crh 	Crumhorn 
crt 	Cornet 
crtt 	Cornett (Zink) 
cv 	    Child's voice 
db 	    Double Bass 
dlcn 	Dulcian 
dom 	Domra 
dulc 	Dulcimer 
egtr 	Electric guitar 
eh 	    English horn (Cor anglais) 
elec 	Electronic Instruments 
epf 	Electric piano 
eq 	    Equal voices 
erhu 	Erhu 
euph 	Euphonium 
fch 	Female chorus 
fda 	Flute d'amore (Tenor flute) 
fgh 	Flugelhorn 
fife 	Fife 
fl 	    Flute 
flag 	Flageolet 
ghca 	Glass harmonica (Bowl organ) 
gl 	    Glockenspiel 
gtr 	Guitar 
harm 	Harmonium 
hca 	Harmonica (Mouth Organ) 
heck 	Heckelphone 
hn 	    Horn 
hp 	    Harp 
hpd 	Harpsichord 
kbd 	Keyboard instrument 
lute 	Lute 
lyre 	Lyre 
mand 	Mandolin 
mar 	Marimba 
mch 	Male chorus 
mez 	Mezzo-soprano 
mus 	Musette 
nar 	Narrator (Reciter) 
ob 	    Oboe 
oca 	Ocarina 
oda 	Oboe d'amore 
om 	    Ondes Martenot 
oph 	Ophicleide 
orch 	Orchestra 
org 	Organ 
oud 	Oud 
pan 	Pan flute (Pan-pipes) 
perc 	Percussion 
pf 	    Piano 
pf3h 	Piano 3 hands 
pf4h 	Piano 4 hands 
pf5h 	Piano 5 hands 
pf6h 	Piano 6 hands 
pflh 	Piano left hand 
pfped 	Pedal piano 
pfrh 	Piano right hand 
picc 	Piccolo 
pipa 	Pipa 
pk 	    Timpani 
ptpt 	Piccolo trumpet 
reb 	Rebec 
rec 	Recorder 
sar 	Sarrusophone 
sax 	Saxophone 
sheng 	Sheng 
shw 	Shawm 
sit 	Sitar 
skbt 	Sackbut 
sop 	Soprano (voice) 
srp 	Serpent 
stpt 	Slide trumpet 
str 	String instruments 
sxh 	Saxhorn 
syn 	Synthesizer 
tba 	Tuba 
tbn 	Trombone 
ten 	Tenor 
thrm 	Theremin 
timp 	Timpani 
tpt 	Trumpet 
uch 	Unison chorus 
uke 	Ukelele (Ukulele) 
v 	    Voice (solo) 
va 	    Viola 
vap 	Viola pomposa 
vc 	    Cello 
vda 	Viola d'amore 
vib 	Vibraphone 
vie 	Vielle (Hurdy-Gurdy) 
viol 	Viol (Viola da gamba) 
vlne 	Violone 
vn 	    Violin 
vuv 	Vuvuzela 
vv 	    Voices (multiple soloists) 
wag 	Wagner tuba 
ww 	    Woodwind instruments 
xiao 	Xiao 
xyl 	Xylophone 
zith 	Zither 
"""

INSTRUMENTS = []
for line in ABBREVIATIONS.split('\n'):
    parts = line.strip().split(maxsplit=1)
    if len(parts) < 2: continue
    name, _, _ = parts[1].partition('(')
    INSTRUMENTS.append((parts[0], name))

'''
ORCHESTRATIONS = {
    'SATB': ('S', 'A', 'T', 'B'),
    'String Quartet': ('Vln1', 'Vln2', 'Vla', 'Vc'),
    'String Orchestra': ('Vln1', 'Vln2', 'Vla', 'Vc', 'Cb'),
    'Chamber Orchestra': ('Vln1', 'Vln2', 'Vla', 'Vc', 'Cb', 
            'Fl1', 'Fl2', 'Cl1', 'Cl2', 'Hn1', 'Hn2', 
            'Tpt1', 'Tpt2', 'Tbn1', 'Tbn2', 'Tuba',
            'Timp', 'Drum', 'Perc'),
    'Custom': (),
}
'''

DOCTYPES = [
    (1, 'PDF'),
    (2, 'Audio'),
    (3, 'Video'),
    (4, 'Source'),
]

LICENCE_TYPES = [
    (2, 'Public Domain'),
    (4, 'Copyright Expired'),
    (6, 'Copyrighted'),
    (10, 'Internal use only'),
]

ACCESS_TYPES = [
    (1, 'Unlimited'),
    (2, 'Approval required'),
]

def tag_to_instrument(tag):
    m = re.match(r'([A-Za-z]+)(\d*)', tag)
    if not m:
        return tag
    l = m.groups()
    return "{0} {1}".format(dict(INSTRUMENTS).get(l[0],l[0]), l[1]).strip()

'''
class Orchestration(models.Model):
    """
    Stores a list of instrument codes as a single entry (space delimited).
    Can be global or ensemble specific
    """
    ensemble = models.ForeignKey('interface.Ensemble', on_delete=models.CASCADE, related_name="orchestrations", null=True, blank=True)
    name = models.CharField(max_length=100)
    instruments = models.TextField()

    def as_list(self):
        tags = [ t.strip() for t in self.instruments.split(' ') ]
        return [ (t, tag_to_instrument(t)) for t in tags if t ]

    def save(self):
        self.as_list()
        super(Orchestration, self).save()

    def __str__(self):
        return self.name
'''

class Item(models.Model):
    """
    Item represents a specic version of a Work in a Project e.g. item in set list or programme
    It also allows works to be shared from one ensemble to another on a per-project basis.
    """
    project = models.ForeignKey('interface.Project', on_delete=models.CASCADE)
    work = models.ForeignKey('Work', on_delete=models.CASCADE, related_name='project_items')
    checkout = models.DateTimeField()
    due = models.DateTimeField(null=True, blank=True)
    returned = models.DateTimeField(null=True, blank=True)
    approved_by = models.ForeignKey('auth.User', on_delete=models.CASCADE)
    order = models.SmallIntegerField(default=0)
    version = models.CharField(max_length=30, blank=True, help_text="Limited to specific version tag")

    class Meta:
        ordering = ['order', 'work']

    def __str__(self):
        return f"<{self.project.slug}:{self.work.slug}>"

class Collection(models.Model):
    """
    Storage location for works (physical or virtual)
    """
    name = models.CharField(max_length=255, help_text="Name of the collection")
    administrators = models.ManyToManyField('auth.User', related_name="collections", help_text="Administrators for this collection")
    location = models.CharField(max_length=100, help_text="Physical location (institution, town...)")
    storage = models.ForeignKey('byostorage.UserStorage', on_delete=models.CASCADE, null=True, blank=True, help_text="Storage for documents")
    notes = models.TextField(blank=True, help_text="Publicly visible notes about collection and loans policy")
    #ensembles = models.ManyToManyField('interface.Ensemble', related_name="collections", through='EnsembleAccess')

    def __str__(self):
        return self.name

class EnsembleAccess(models.Model):
    """
    Can have different access levels to a collection
    """
    ensemble = models.ForeignKey('interface.Ensemble', on_delete=models.CASCADE, related_name="allowed_collections")
    collection = models.ForeignKey(Collection, on_delete=models.CASCADE, related_name="allowed_ensembles")
    access_type = models.PositiveSmallIntegerField(choices=ACCESS_TYPES, default=2)

    class Meta:
        verbose_name_plural = "Ensemble access"

class Work(models.Model):
    """
    A musical work 'owned' by a collection from a licencing perspective.
    """
    collection = models.ForeignKey(Collection, on_delete=models.CASCADE, related_name="works", help_text="Owner")
    slug = models.SlugField(max_length=100, editable=False)
    name = models.CharField(max_length=255)
    edition = models.CharField(max_length=100, blank=True, help_text="Edition details")
    parent = models.ForeignKey('Work', null=True, blank=True, on_delete=models.SET_NULL, related_name="related_works",
            help_text="Arrangement of another work or part of an anthology")
    composer = models.CharField(max_length=255, blank=True, help_text="Use Composer / Arranger format")
    #orchestration = models.ForeignKey(Orchestration, null=True, on_delete=models.SET_NULL, related_name='works', blank=True)
    orchestration = models.CharField(max_length=255, blank=True, help_text="IMDB format instrumentation")
    parts = models.JSONField(null=True, blank=True)

    # Collection details
    collection = models.ForeignKey(Collection, on_delete=models.CASCADE, related_name="works")
    code = models.CharField(max_length=100, blank=True, help_text="Collection specific code or number")
    licence = models.PositiveSmallIntegerField(choices=LICENCE_TYPES, default=6, help_text="Copyright status")
    max_loans = models.IntegerField(default=1, help_text="How many projects can this work be attached to")
    
    # Extra info
    running_time = models.IntegerField(null=True, blank=True, help_text="Running time in seconds")
    notes = models.TextField(blank=True)
    tag_list = models.CharField(max_length=255, blank=True, help_text="Multiple tags for the work")
    
    projects = models.ManyToManyField('interface.Project', through='Item', related_name="works", help_text="Current usage")

    @property
    def duration(self):
        if self.running_time is None: 
            return "-:--"
        return "{0:d}:{1:02d}".format(int(self.running_time / 60), self.running_time % 60)

    @property
    def tags(self):
        return self.tag_list.split(';') if self.tag_list else []

    @tags.setter
    def set_tags(self, tags):
        self.tag_list = ";".join(tags)

    @property
    def digital_parts(self):
        return Part.objects.filter(doc__work=self.pk)

    @property
    def physical_parts(self):
        if not self.parts:
            return []
        return [ (tag_to_instrument(k), v) for (k, v) in self.parts.items() ]

    #@property
    #def instruments(self):
    #    return self.orchestration.as_list()

    def save(self, *args, **kwargs):
        if not self.slug:
            self.slug = slugify(self.name)
        super(Work, self).save(*args, **kwargs)

    @property
    def active_projects(self):
        return self.projects.filter(active=True)

    @property
    def current_loans(self):
        return self.project_items.filter(checkout__lte=now(), returned=None).select_related('project')

    @cached_property
    def loans(self):
        try:
            return self.loan_count
        except AttributeError:
            return self.project_items.filter(checkout__lte=now(), returned=None).count()

    @property
    def is_available(self):
        if self.max_loans < 0:
            return True
        return self.max_loans > self.loans

    @property
    def available(self):
        if self.max_loans < 0:
            return 'Unlimited'
        a = self.max_loans - self.loans
        return '{0} of {1}'.format(max(a, 0), self.max_loans)

    @property
    def identifier(self):
        return f"{self.collection.pk:03d}-{self.pk:03d}"


    def __str__(self):
        return f"{self.name} ({self.composer})"

def doc_upload_filename(doc, filename):
    storage = doc.work.collection.storage
    if not storage:
        raise RuntimeError("Collection has no storage attached")
    return f'{storage}:works/{doc.work.slug}-{doc.work.pk}/{filename}'

class Document(models.Model):
    """
    Document represents a single file stored in the storage backend.
    """
    work = models.ForeignKey('Work', on_delete=models.CASCADE, related_name="docs")
    doctype = models.PositiveSmallIntegerField(choices=DOCTYPES, default=1)
    upload = models.FileField(upload_to=doc_upload_filename, storage=library_storage)
    created = models.DateTimeField(auto_now_add=True)
    version = models.CharField(max_length=30, blank=True)

    def __str__(self):
        return self.upload.name

class Part(models.Model):
    """
    Part is a tagged portion of a Document
    """
    doc = models.ForeignKey(Document, on_delete=models.CASCADE, related_name="parts")
    tag = models.SlugField(max_length=20)
    start = models.SmallIntegerField(null=True, blank=True)
    end = models.SmallIntegerField(null=True, blank=True)
    notes = models.TextField(blank=True)

    class Meta:
        ordering = ['doc', 'start', 'pk']

    @property
    def instrument(self):
        return tag_to_instrument(self.tag)

    @property
    def filename(self):
        return slugify(f'{self.doc.work.name}_{self.instrument}') + '.pdf'

    @property 
    def pagerange(self):
        if self.start:
            if self.end:
                return f"{self.start}-{self.end}"
            return str(self.start)
        return "all"

    def __str__(self):
        return f'{self.doc.upload} [{self.pagerange}]'