-- Этап 2. Создание витринных таблиц --

--  Витрина lesson_popularity_summary
DROP TABLE IF EXISTS dsolovianov.lesson_popularity_summary ON CLUSTER clickhouse_cluster SYNC;

CREATE TABLE dsolovianov.lesson_popularity_summary ON CLUSTER clickhouse_cluster (
    lesson_id UInt32,
    lesson_title String,
    course_id UInt32,
    course_title String,
    total_views UInt64,
    unique_users UInt64,
    first_view DateTime,
    last_view DateTime
) ENGINE = ReplicatedMergeTree(
    '/clickhouse/tables/{shard}/dsolovianov/lesson_popularity_summary',
    '{replica}'
)
ORDER BY (course_id, lesson_id);

CREATE MATERIALIZED VIEW dsolovianov.lesson_popularity_summary_mv ON CLUSTER clickhouse_cluster
TO dsolovianov.lesson_popularity_summary
AS
SELECT 
    l.lesson_id AS lesson_id,
    l.title AS lesson_title,
    l.course_id AS course_id,
    c.title AS course_title,
    COUNT(v.viewed_at) AS total_views,
    COUNT(DISTINCT v.user_id) AS unique_users,
    MIN(v.viewed_at) AS first_view,
    MAX(v.viewed_at) AS last_view
FROM dsolovianov.core_fact_lesson_views v
LEFT JOIN dsolovianov.core_dim_lesson l ON v.lesson_id = l.lesson_id
LEFT JOIN dsolovianov.core_dim_course c ON l.course_id = c.course_id
GROUP BY l.lesson_id, l.title, l.course_id, c.title;

INSERT INTO dsolovianov.lesson_popularity_summary
SELECT 
    l.lesson_id AS lesson_id,
    l.title AS lesson_title,
    l.course_id AS course_id,
    c.title AS course_title,
    COUNT(v.viewed_at) AS total_views,
    COUNT(DISTINCT v.user_id) AS unique_users,
    MIN(v.viewed_at) AS first_view,
    MAX(v.viewed_at) AS last_view
FROM dsolovianov.core_dim_lesson l
JOIN dsolovianov.core_dim_course c ON l.course_id = c.course_id
LEFT JOIN dsolovianov.core_fact_lesson_views v ON l.lesson_id = v.lesson_id
GROUP BY l.lesson_id, l.title, l.course_id, c.title;

--  Витрину inactive_users_summary

DROP TABLE IF EXISTS dsolovianov.inactive_users_summary ON CLUSTER clickhouse_cluster SYNC;

CREATE TABLE dsolovianov.inactive_users_summary ON CLUSTER clickhouse_cluster (
    user_id UInt32,
    name String,
    email String,
    age UInt8,
    registered_courses_count UInt32,
    registration_date Date
) ENGINE = ReplicatedMergeTree(
    '/clickhouse/tables/{shard}/dsolovianov/inactive_users_summary',
    '{replica}'
)
ORDER BY user_id;

CREATE MATERIALIZED VIEW dsolovianov.inactive_users_summary_mv ON CLUSTER clickhouse_cluster
TO dsolovianov.inactive_users_summary
AS
SELECT 
    u.user_id AS user_id,
    u.name AS name,
    u.email AS email,
    u.age AS age,
    COUNT(DISTINCT e.course_id) AS registered_courses_count,
    u.registration_date AS registration_date
FROM dsolovianov.core_dim_user u
LEFT JOIN dsolovianov.core_enrollments e ON u.user_id = e.user_id
WHERE u.user_id NOT IN (SELECT DISTINCT user_id FROM dsolovianov.core_fact_lesson_views)
GROUP BY u.user_id, u.name, u.email, u.age, u.registration_date;

INSERT INTO dsolovianov.inactive_users_summary
SELECT 
    u.user_id AS user_id,
    u.name AS name,
    u.email AS email,
    u.age AS age,
    COUNT(DISTINCT e.course_id) AS registered_courses_count,
    u.registration_date AS registration_date
FROM dsolovianov.core_dim_user u
LEFT JOIN dsolovianov.core_enrollments e ON u.user_id = e.user_id
WHERE u.user_id NOT IN (SELECT DISTINCT user_id FROM dsolovianov.core_fact_lesson_views)
GROUP BY u.user_id, u.name, u.email, u.age, u.registration_date;

-- Витрина course_completion_rate

DROP TABLE IF EXISTS dsolovianov.course_completion_rate ON CLUSTER clickhouse_cluster SYNC;

CREATE TABLE dsolovianov.course_completion_rate ON CLUSTER clickhouse_cluster (
    user_id UInt32,
    user_name String,
    course_id UInt32,
    course_title String,
    lessons_in_course UInt32,
    lessons_viewed UInt32,
    completion_rate Float32
) ENGINE = ReplicatedMergeTree(
    '/clickhouse/tables/{shard}/dsolovianov/course_completion_rate',
    '{replica}'
)
ORDER BY (user_id, course_id);

DROP TABLE IF EXISTS dsolovianov.course_completion_rate_mv ON CLUSTER clickhouse_cluster SYNC;

CREATE MATERIALIZED VIEW dsolovianov.course_completion_rate_mv ON CLUSTER clickhouse_cluster
TO dsolovianov.course_completion_rate
AS
SELECT 
    e.user_id AS user_id,
    u.name AS user_name,
    e.course_id AS course_id,
    c.title AS course_title,
    (
        SELECT COUNT(*)
        FROM dsolovianov.core_dim_lesson l
        WHERE l.course_id = e.course_id
    ) AS lessons_in_course,
    (
        SELECT COUNT(DISTINCT v.lesson_id)
        FROM dsolovianov.core_fact_lesson_views v
        JOIN dsolovianov.core_dim_lesson l ON v.lesson_id = l.lesson_id
        WHERE v.user_id = e.user_id AND l.course_id = e.course_id
    ) AS lessons_viewed,
    (
        SELECT COUNT(DISTINCT v.lesson_id)
        FROM dsolovianov.core_fact_lesson_views v
        JOIN dsolovianov.core_dim_lesson l ON v.lesson_id = l.lesson_id
        WHERE v.user_id = e.user_id AND l.course_id = e.course_id
    ) / (
        SELECT COUNT(*)
        FROM dsolovianov.core_dim_lesson l
        WHERE l.course_id = e.course_id
    ) AS completion_rate
FROM dsolovianov.core_enrollments e
JOIN dsolovianov.core_dim_user u ON e.user_id = u.user_id
JOIN dsolovianov.core_dim_course c ON e.course_id = c.course_id
GROUP BY e.user_id, u.name, e.course_id, c.title;

INSERT INTO dsolovianov.course_completion_rate
SELECT 
    e.user_id AS user_id,
    u.name AS user_name,
    e.course_id AS course_id,
    c.title AS course_title,
    (
        SELECT COUNT(*)
        FROM dsolovianov.core_dim_lesson l
        WHERE l.course_id = e.course_id
    ) AS lessons_in_course,
    COALESCE(
        (
            SELECT COUNT(DISTINCT v.lesson_id)
            FROM dsolovianov.core_fact_lesson_views v
            JOIN dsolovianov.core_dim_lesson l ON v.lesson_id = l.lesson_id
            WHERE v.user_id = e.user_id AND l.course_id = e.course_id
        ), 0
    ) AS lessons_viewed,
    COALESCE(
        (
            SELECT COUNT(DISTINCT v.lesson_id)
            FROM dsolovianov.core_fact_lesson_views v
            JOIN dsolovianov.core_dim_lesson l ON v.lesson_id = l.lesson_id
            WHERE v.user_id = e.user_id AND l.course_id = e.course_id
        ), 0
    ) / (
        SELECT COUNT(*)
        FROM dsolovianov.core_dim_lesson l
        WHERE l.course_id = e.course_id
    ) AS completion_rate
FROM dsolovianov.core_enrollments e
JOIN dsolovianov.core_dim_user u ON e.user_id = u.user_id
JOIN dsolovianov.core_dim_course c ON e.course_id = c.course_id
GROUP BY e.user_id, u.name, e.course_id, c.title;