from math import ceil
from typing import Optional, Dict, List
from datetime import datetime
from szurubooru import db, model, errors, rest, search
from szurubooru.func import (
    auth, tags, posts, snapshots, favorites, scores, serialization, versions, metrics)


_search_executor_config = search.configs.PostSearchConfig()
_search_executor = search.Executor(_search_executor_config)


def _get_post_id(params: Dict[str, str]) -> int:
    try:
        return int(params['post_id'])
    except TypeError:
        raise posts.InvalidPostIdError(
            'Invalid post ID: %r.' % params['post_id'])


def _get_post(params: Dict[str, str]) -> model.Post:
    return posts.get_post_by_id(_get_post_id(params))


def _serialize_post(
        ctx: rest.Context, post: Optional[model.Post]) -> rest.Response:
    return posts.serialize_post(
        post,
        ctx.user,
        options=serialization.get_serialization_options(ctx))


@rest.routes.get('/posts/?')
def get_posts(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:list')
    _search_executor_config.user = ctx.user
    return _search_executor.execute_and_serialize(
        ctx, lambda post: _serialize_post(ctx, post))


@rest.routes.post('/posts/?')
def create_post(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    anonymous = ctx.get_param_as_bool('anonymous', default=False)
    if anonymous:
        auth.verify_privilege(ctx.user, 'posts:create:anonymous')
    else:
        auth.verify_privilege(ctx.user, 'posts:create:identified')
    content = ctx.get_file('content')
    tag_names = ctx.get_param_as_string_list('tags', default=[])
    safety = ctx.get_param_as_string('safety')
    source = ctx.get_param_as_string('source', default='')
    if ctx.has_param('contentUrl') and not source:
        source = ctx.get_param_as_string('contentUrl', default='')
    relations = ctx.get_param_as_int_list('relations', default=[])
    notes = ctx.get_param_as_list('notes', default=[])
    flags = ctx.get_param_as_string_list('flags', default=[])

    post, new_tags = posts.create_post(
        content, tag_names, None if anonymous else ctx.user)
    if len(new_tags):
        auth.verify_privilege(ctx.user, 'tags:create')
    posts.update_post_safety(post, safety)
    posts.update_post_source(post, source)
    posts.update_post_relations(post, relations)
    posts.update_post_notes(post, notes)
    posts.update_post_flags(post, flags)
    posts.test_sound(post, content)
    if ctx.has_file('thumbnail'):
        posts.update_post_thumbnail(post, ctx.get_file('thumbnail'))
    ctx.session.add(post)
    ctx.session.flush()
    create_snapshots_for_post(post, new_tags, None if anonymous else ctx.user)
    alternate_format_posts = posts.generate_alternate_formats(post, content)
    for alternate_post, alternate_post_new_tags in alternate_format_posts:
        create_snapshots_for_post(
            alternate_post,
            alternate_post_new_tags,
            None if anonymous else ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, post)


def create_snapshots_for_post(
        post: model.Post,
        new_tags: List[model.Tag],
        user: Optional[model.User]):
    snapshots.create(post, user)
    for tag in new_tags:
        snapshots.create(tag, user)


@rest.routes.get('/post/(?P<post_id>[^/]+)/?')
def get_post(ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:view')
    post = _get_post(params)
    return _serialize_post(ctx, post)


@rest.routes.put('/post/(?P<post_id>[^/]+)/?')
def update_post(ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    post = _get_post(params)
    versions.verify_version(post, ctx)
    versions.bump_version(post)
    if ctx.has_file('content'):
        auth.verify_privilege(ctx.user, 'posts:edit:content')
        posts.update_post_content(post, ctx.get_file('content'))
    if ctx.has_param('tags'):
        auth.verify_privilege(ctx.user, 'posts:edit:tags')
        new_tags = posts.update_post_tags(
            post, ctx.get_param_as_string_list('tags'))
        if len(new_tags):
            auth.verify_privilege(ctx.user, 'tags:create')
            db.session.flush()
            for tag in new_tags:
                snapshots.create(tag, ctx.user)
    if ctx.has_param('safety'):
        auth.verify_privilege(ctx.user, 'posts:edit:safety')
        posts.update_post_safety(post, ctx.get_param_as_string('safety'))
    if ctx.has_param('source'):
        auth.verify_privilege(ctx.user, 'posts:edit:source')
        posts.update_post_source(post, ctx.get_param_as_string('source'))
    elif ctx.has_param('contentUrl'):
        posts.update_post_source(post, ctx.get_param_as_string('contentUrl'))
    if ctx.has_param('relations'):
        auth.verify_privilege(ctx.user, 'posts:edit:relations')
        posts.update_post_relations(
            post, ctx.get_param_as_int_list('relations'))
    if ctx.has_param('notes'):
        auth.verify_privilege(ctx.user, 'posts:edit:notes')
        posts.update_post_notes(post, ctx.get_param_as_list('notes'))
    if ctx.has_param('flags'):
        auth.verify_privilege(ctx.user, 'posts:edit:flags')
        posts.update_post_flags(post, ctx.get_param_as_string_list('flags'))
    if ctx.has_file('thumbnail'):
        auth.verify_privilege(ctx.user, 'posts:edit:thumbnail')
        posts.update_post_thumbnail(post, ctx.get_file('thumbnail'))
    if ctx.has_param('metrics'):
        auth.verify_privilege(ctx.user, 'metrics:edit:posts')
        metrics.update_or_create_post_metrics(
            post, ctx.get_param_as_list('metrics'))
    if ctx.has_param('metricRanges'):
        auth.verify_privilege(ctx.user, 'metrics:edit:posts')
        metrics.update_or_create_post_metric_ranges(
            post, ctx.get_param_as_list('metricRanges'))

    post.last_edit_time = datetime.utcnow()
    ctx.session.flush()
    snapshots.modify(post, ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, post)


@rest.routes.delete('/post/(?P<post_id>[^/]+)/?')
def delete_post(ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:delete')
    post = _get_post(params)
    versions.verify_version(post, ctx)
    snapshots.delete(post, ctx.user)
    posts.delete(post)
    ctx.session.commit()
    return {}


@rest.routes.post('/post-merge/?')
def merge_posts(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    source_post_id = ctx.get_param_as_int('remove')
    target_post_id = ctx.get_param_as_int('mergeTo')
    source_post = posts.get_post_by_id(source_post_id)
    target_post = posts.get_post_by_id(target_post_id)
    replace_content = ctx.get_param_as_bool('replaceContent')
    versions.verify_version(source_post, ctx, 'removeVersion')
    versions.verify_version(target_post, ctx, 'mergeToVersion')
    versions.bump_version(target_post)
    auth.verify_privilege(ctx.user, 'posts:merge')
    posts.merge_posts(source_post, target_post, replace_content)
    snapshots.merge(source_post, target_post, ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, target_post)


@rest.routes.get('/featured-post/?')
def get_featured_post(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:view:featured')
    post = posts.try_get_featured_post()
    return _serialize_post(ctx, post)


@rest.routes.post('/featured-post/?')
def set_featured_post(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:feature')
    post_id = ctx.get_param_as_int('id')
    post = posts.get_post_by_id(post_id)
    featured_post = posts.try_get_featured_post()
    if featured_post and featured_post.post_id == post.post_id:
        raise posts.PostAlreadyFeaturedError(
            'Post %r is already featured.' % post_id)
    posts.feature_post(post, ctx.user)
    snapshots.modify(post, ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, post)


@rest.routes.put('/post/(?P<post_id>[^/]+)/score/?')
def set_post_score(ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:score')
    post = _get_post(params)
    score = ctx.get_param_as_int('score')
    scores.set_score(post, ctx.user, score)
    ctx.session.commit()
    return _serialize_post(ctx, post)


@rest.routes.delete('/post/(?P<post_id>[^/]+)/score/?')
def delete_post_score(
        ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:score')
    post = _get_post(params)
    scores.delete_score(post, ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, post)


@rest.routes.post('/post/(?P<post_id>[^/]+)/favorite/?')
def add_post_to_favorites(
        ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:favorite')
    post = _get_post(params)
    favorites.set_favorite(post, ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, post)


@rest.routes.delete('/post/(?P<post_id>[^/]+)/favorite/?')
def delete_post_from_favorites(
        ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:favorite')
    post = _get_post(params)
    favorites.unset_favorite(post, ctx.user)
    ctx.session.commit()
    return _serialize_post(ctx, post)


@rest.routes.get('/post/(?P<post_id>[^/]+)/around/?')
def get_posts_around(
        ctx: rest.Context, params: Dict[str, str]) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:list')
    _search_executor_config.user = ctx.user
    post_id = _get_post_id(params)
    return _search_executor.get_around_and_serialize(
        ctx, post_id, lambda post: _serialize_post(ctx, post))


@rest.routes.post('/posts/reverse-search/?')
def get_posts_by_image(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:reverse_search')
    content = ctx.get_file('content')

    try:
        lookalikes = posts.search_by_image(content)
    except (errors.ThirdPartyError, errors.ProcessingError):
        lookalikes = []

    return {
        'exactPost':
            _serialize_post(ctx, posts.search_by_image_exact(content)),
        'similarPosts':
            [
                {
                    'distance': lookalike.distance,
                    'post': _serialize_post(ctx, lookalike.post),
                }
                for lookalike in lookalikes
            ],
    }


@rest.routes.get('/posts/median/?')
def get_posts_median(
        ctx: rest.Context, _params: Dict[str, str] = {}) -> rest.Response:
    auth.verify_privilege(ctx.user, 'posts:list')
    _search_executor_config.user = ctx.user
    query_text = ctx.get_param_as_string('query', default='')
    total_count = _search_executor.count(query_text)
    offset = ceil(total_count / 2) - 1
    _, results = _search_executor.execute(query_text, offset, 1)
    return {
        'query': query_text,
        'offset': offset,
        'limit': 1,
        'total': len(results),
        'results': list([_serialize_post(ctx, post) for post in results])
    }