import random
from django.conf import settings
from django.db import models
from django.utils.text import slugify
from django.utils.translation import gettext_lazy as _
from apps.profiles.models.institution import Institution


class Project(models.Model):
    class Status(models.TextChoices):
        PLANNING = 'planning', _('Planning')
        ACTIVE = 'active', _('Active / In Progress')
        ON_HOLD = 'on_hold', _('On Hold')
        COMPLETED = 'completed', _('Completed')

    title = models.CharField(
        max_length=255,
        verbose_name=_('Project Title')
    )
    slug = models.SlugField(
        max_length=255,
        unique=True,
        allow_unicode=True,
        blank=True,
        null=True,
        verbose_name=_('Slug / URL Identifier')
    )
    description = models.TextField(
        blank=True,
        null=True,
        verbose_name=_('Project Description & Objectives')
    )
    owner_institution = models.ForeignKey(
        Institution,
        on_delete=models.CASCADE,
        related_name='owned_projects',
        verbose_name=_('Lead / Owner Institution')
    )
    collaborating_institutions = models.ManyToManyField(
        Institution,
        blank=True,
        related_name='collaborative_projects',
        verbose_name=_('Collaborating Institutions')
    )
    category = models.CharField(
        max_length=100,
        blank=True,
        null=True,
        verbose_name=_('Project Category'),
        help_text=_('e.g. Cultural Diplomacy, Educational Academy, Interfaith Dialogue, Humanitarian Relief')
    )
    status = models.CharField(
        max_length=20,
        choices=Status.choices,
        default=Status.ACTIVE,
        verbose_name=_('Project Status')
    )
    progress_percentage = models.PositiveSmallIntegerField(
        default=0,
        verbose_name=_('Progress Percentage (0-100)')
    )
    budget = models.CharField(
        max_length=100,
        blank=True,
        null=True,
        verbose_name=_('Estimated Budget'),
        help_text=_('e.g. $50,000 or €35,000')
    )
    team_size = models.PositiveIntegerField(
        default=1,
        verbose_name=_('Team Size')
    )
    cover_image = models.ImageField(
        upload_to='projects/covers/%Y/%m/',
        blank=True,
        null=True,
        verbose_name=_('Cover Image')
    )
    start_date = models.DateField(
        null=True,
        blank=True,
        verbose_name=_('Start Date')
    )
    estimated_end_date = models.DateField(
        null=True,
        blank=True,
        verbose_name=_('Estimated End Date')
    )
    actual_end_date = models.DateField(
        null=True,
        blank=True,
        verbose_name=_('Actual Completion Date')
    )
    created_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='created_projects',
        verbose_name=_('Created By')
    )
    created_at = models.DateTimeField(
        auto_now_add=True,
        verbose_name=_('Created At')
    )
    updated_at = models.DateTimeField(
        auto_now=True,
        verbose_name=_('Updated At')
    )

    class Meta:
        ordering = ('-created_at',)
        verbose_name = _('Collaborative Project')
        verbose_name_plural = _('Collaborative Projects')

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

    def save(self, *args, **kwargs):
        is_new = self.pk is None
        if not self.slug:
            base_slug = slugify(self.title, allow_unicode=True) or f"project-{random.randint(1000, 9999)}"
            slug = base_slug
            counter = 1
            while Project.objects.filter(slug=slug).exclude(pk=self.pk).exists():
                slug = f"{base_slug}-{counter}"
                counter += 1
            self.slug = slug

        super().save(*args, **kwargs)

        if is_new:
            self._create_default_kanban_columns()

    def _create_default_kanban_columns(self):
        default_columns = [
            {'name': 'To Do', 'code': 'todo', 'order': 1, 'color': '#94a3b8'},
            {'name': 'In Progress', 'code': 'in_progress', 'order': 2, 'color': '#3b82f6'},
            {'name': 'Review', 'code': 'review', 'order': 3, 'color': '#f59e0b'},
            {'name': 'Done', 'code': 'done', 'order': 4, 'color': '#10b981'},
        ]
        for col in default_columns:
            KanbanColumn.objects.create(
                project=self,
                name=col['name'],
                code=col['code'],
                order=col['order'],
                color=col['color']
            )

    def can_user_edit(self, user):
        if not user or not user.is_authenticated:
            return False
        if getattr(user, 'is_super_admin', False):
            return True
        if getattr(user, 'is_regional_admin', False):
            if hasattr(user, 'can_manage_region'):
                if self.owner_institution and user.can_manage_region(self.owner_institution.region):
                    return True
                for collab in self.collaborating_institutions.all():
                    if user.can_manage_region(collab.region):
                        return True
            return False
        # Check owner institution
        if self.owner_institution and self.owner_institution.is_editor(user):
            return True
        # Check collaborating institutions
        for collab in self.collaborating_institutions.all():
            if collab.is_editor(user):
                return True
        return False



class KanbanColumn(models.Model):
    project = models.ForeignKey(
        Project,
        on_delete=models.CASCADE,
        related_name='columns',
        verbose_name=_('Project')
    )
    name = models.CharField(
        max_length=100,
        verbose_name=_('Column Name')
    )
    code = models.CharField(
        max_length=50,
        default='todo',
        verbose_name=_('Column Code Identifier')
    )
    order = models.IntegerField(
        default=0,
        verbose_name=_('Display Order')
    )
    color = models.CharField(
        max_length=20,
        default='#6366f1',
        blank=True,
        null=True,
        verbose_name=_('Badge / Header Color')
    )

    class Meta:
        ordering = ('order', 'id')
        verbose_name = _('Kanban Column')
        verbose_name_plural = _('Kanban Columns')

    def __str__(self):
        return f"{self.project.title} - {self.name}"


class KanbanTask(models.Model):
    class Priority(models.TextChoices):
        LOW = 'low', _('Low')
        MEDIUM = 'medium', _('Medium')
        HIGH = 'high', _('High')
        URGENT = 'urgent', _('Urgent')

    project = models.ForeignKey(
        Project,
        on_delete=models.CASCADE,
        related_name='tasks',
        verbose_name=_('Project')
    )
    column = models.ForeignKey(
        KanbanColumn,
        on_delete=models.CASCADE,
        related_name='tasks',
        verbose_name=_('Kanban Column')
    )
    title = models.CharField(
        max_length=255,
        verbose_name=_('Task Title')
    )
    description = models.TextField(
        blank=True,
        null=True,
        verbose_name=_('Task Description')
    )
    priority = models.CharField(
        max_length=20,
        choices=Priority.choices,
        default=Priority.MEDIUM,
        verbose_name=_('Priority')
    )
    assignee = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='assigned_tasks',
        verbose_name=_('Assignee User')
    )
    due_date = models.DateField(
        null=True,
        blank=True,
        verbose_name=_('Due Date')
    )
    labels = models.JSONField(
        default=list,
        blank=True,
        verbose_name=_('Task Labels')
    )
    order = models.IntegerField(
        default=0,
        verbose_name=_('Display Order within Column')
    )
    created_at = models.DateTimeField(
        auto_now_add=True,
        verbose_name=_('Created At')
    )
    updated_at = models.DateTimeField(
        auto_now=True,
        verbose_name=_('Updated At')
    )

    class Meta:
        ordering = ('order', '-updated_at')
        verbose_name = _('Kanban Task')
        verbose_name_plural = _('Kanban Tasks')

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


class ProjectDocument(models.Model):
    class DocumentType(models.TextChoices):
        MOU = 'mou', _('MOU / Bilateral Agreement')
        REPORT = 'report', _('Progress / Milestone Report')
        CONTRACT = 'contract', _('Contract / Agreement')
        OTHER = 'other', _('Other Document')

    project = models.ForeignKey(
        Project,
        on_delete=models.CASCADE,
        related_name='documents',
        verbose_name=_('Project')
    )
    title = models.CharField(
        max_length=255,
        verbose_name=_('Document Title')
    )
    file = models.FileField(
        upload_to='projects/docs/%Y/%m/',
        verbose_name=_('Document File')
    )
    doc_type = models.CharField(
        max_length=50,
        choices=DocumentType.choices,
        default=DocumentType.MOU,
        verbose_name=_('Document Type')
    )
    uploaded_by = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        on_delete=models.SET_NULL,
        null=True,
        blank=True,
        related_name='uploaded_project_documents',
        verbose_name=_('Uploaded By')
    )
    uploaded_at = models.DateTimeField(
        auto_now_add=True,
        verbose_name=_('Uploaded At')
    )

    class Meta:
        ordering = ('-uploaded_at',)
        verbose_name = _('Project Document')
        verbose_name_plural = _('Project Documents')

    def __str__(self):
        return f"{self.project.title} - {self.title}"