import json
from typing import Optional

from django import urls
from django.contrib import admin
from django.http import HttpRequest
from django.utils.html import format_html

from .models import (
    BotSetting,
    DeletedMessage,
    DocumentationLink,
    Infraction,
    LogEntry,
    MessageDeletionContext,
    Nomination,
    OffTopicChannelName,
    Role,
    Tag,
    User
)


class LogEntryAdmin(admin.ModelAdmin):
    """Allows viewing logs in the Django Admin without allowing edits."""

    actions = None
    list_display = ('timestamp', 'application', 'level', 'message')
    fieldsets = (
        ('Overview', {'fields': ('timestamp', 'application', 'logger_name')}),
        ('Metadata', {'fields': ('level', 'module', 'line')}),
        ('Contents', {'fields': ('message',)})
    )
    list_filter = ('application', 'level', 'timestamp')
    search_fields = ('message',)
    readonly_fields = (
        'application',
        'logger_name',
        'timestamp',
        'level',
        'module',
        'line',
        'message'
    )

    def has_add_permission(self, request: HttpRequest) -> bool:
        """Deny manual LogEntry creation."""
        return False

    def has_delete_permission(self, request: HttpRequest, obj: Optional[LogEntry] = None) -> bool:
        """Deny LogEntry deletion."""
        return False


class DeletedMessageAdmin(admin.ModelAdmin):
    """Admin formatting for the DeletedMessage model."""

    readonly_fields = (
        "id",
        "author",
        "channel_id",
        "content",
        "embed_data",
        "context",
        "view_full_log"
    )

    exclude = ("embeds", "deletion_context")

    search_fields = (
        "id",
        "content",
        "author__name",
        "author__id",
        "deletion_context__actor__name",
        "deletion_context__actor__id"
    )

    @staticmethod
    def embed_data(instance: DeletedMessage) -> Optional[str]:
        """Format embed data in a code block for better readability."""
        if instance.embeds:
            return format_html(
                "<pre><code>{0}</code></pre>",
                json.dumps(instance.embeds, indent=4)
            )

    @staticmethod
    def context(instance: DeletedMessage) -> str:
        """Provide full context info with a link through to context admin view."""
        link = urls.reverse(
            "admin:api_messagedeletioncontext_change",
            args=[instance.deletion_context.id]
        )
        details = (
            f"Deleted by {instance.deletion_context.actor} at "
            f"{instance.deletion_context.creation}"
        )
        return format_html("<a href='{0}'>{1}</a>", link, details)

    @staticmethod
    def view_full_log(instance: DeletedMessage) -> str:
        """Provide a link to the message logs for the relevant context."""
        return format_html(
            "<a href='{0}'>Click to view full context log</a>",
            instance.deletion_context.log_url
        )


class MessageDeletionContextAdmin(admin.ModelAdmin):
    """Admin formatting for the MessageDeletionContext model."""

    readonly_fields = ("actor", "creation", "message_log")

    @staticmethod
    def message_log(instance: MessageDeletionContext) -> str:
        """Provide a formatted link to the message logs for the context."""
        return format_html(
            "<a href='{0}'>Click to see deleted message log</a>",
            instance.log_url
        )


admin.site.register(BotSetting)
admin.site.register(DeletedMessage, DeletedMessageAdmin)
admin.site.register(DocumentationLink)
admin.site.register(Infraction)
admin.site.register(LogEntry, LogEntryAdmin)
admin.site.register(MessageDeletionContext, MessageDeletionContextAdmin)
admin.site.register(Nomination)
admin.site.register(OffTopicChannelName)
admin.site.register(Role)
admin.site.register(Tag)
admin.site.register(User)