-- tests/schema_migration_test.lua
-- Тестирование миграции схемы данных

local function setup_schema_test()
    print("=== Setup Schema Migration Test ===")
    
    db.execute("CREATE DATABASE IF NOT EXISTS schema_test")
    db.execute("USE schema_test")
    
    -- Создаём коллекцию со старой схемой
    db.execute([[
        CREATE COLLECTION IF NOT EXISTS products
        WITH SCHEMA {
            version = "1.0.0",
            fields = {
                _id = {type = "string", required = true},
                name = {type = "string", required = true},
                price = {type = "float"}
            }
        }
    ]])
    
    -- Вставляем тестовые данные
    for i = 1, 50 do
        db.execute(string.format([[
            INSERT INTO products VALUES {
                _id = "prod_%d",
                name = "Product %d",
                price = %.2f
            }
        ]], i, i, math.random(100, 1000) / 100))
    end
    
    print("Inserted 50 test products")
    
    return true
end

local function test_schema_version()
    print("\n=== Test 1: Schema Version ===")
    
    local version = db.execute("SHOW SCHEMA VERSION")
    print(string.format("Current schema version: %s", version))
    
    if version and version ~= "" then
        print("✅ Schema version retrieved")
        return true
    else
        print("❌ Failed to get schema version")
        return false
    end
end

local function test_add_field_migration()
    print("\n=== Test 2: Add Field Migration ===")
    
    -- Миграция: добавляем поле description
    local migration = [[
        MIGRATE SCHEMA products
        ADD FIELD description {
            type = "string",
            default = "No description",
            required = false
        }
    ]]
    
    local result = db.execute(migration)
    print("Migration result: " .. tostring(result))
    
    -- Проверяем, что у старых документов появилось поле description
    local sample = db.execute("SELECT * FROM products LIMIT 1")
    local sample_data = db.json_decode(sample)
    
    if sample_data[1].description == "No description" then
        print("✅ Field added and default value applied")
        return true
    else
        print("❌ Field migration failed")
        return false
    end
end

local function test_change_field_type_migration()
    print("\n=== Test 3: Change Field Type Migration ===")
    
    -- Миграция: меняем тип price на string с префиксом "$"
    local migration = [[
        MIGRATE SCHEMA products
        MODIFY FIELD price
        TYPE string
        TRANSFORM value -> "$" .. tostring(value)
    ]]
    
    local result = db.execute(migration)
    print("Migration result: " .. tostring(result))
    
    -- Проверяем преобразование
    local sample = db.execute("SELECT price FROM products LIMIT 1")
    local sample_data = db.json_decode(sample)
    
    if string.sub(sample_data[1].price, 1, 1) == "$" then
        print("✅ Field type conversion successful")
        return true
    else
        print("❌ Field type conversion failed")
        return false
    end
end

local function test_rename_field_migration()
    print("\n=== Test 4: Rename Field Migration ===")
    
    -- Миграция: переименовываем name в title
    local migration = [[
        MIGRATE SCHEMA products
        RENAME FIELD name TO title
    ]]
    
    local result = db.execute(migration)
    print("Migration result: " .. tostring(result))
    
    -- Проверяем, что поле переименовано
    local sample = db.execute("SELECT title FROM products LIMIT 1")
    local sample_data = db.json_decode(sample)
    
    local check_name = db.execute("SELECT name FROM products LIMIT 1")
    
    if sample_data[1].title and check_name == "null" then
        print("✅ Field renamed successfully")
        return true
    else
        print("❌ Field rename failed")
        return false
    end
end

local function test_remove_field_migration()
    print("\n=== Test 5: Remove Field Migration ===")
    
    -- Миграция: удаляем поле description
    local migration = [[
        MIGRATE SCHEMA products
        REMOVE FIELD description
    ]]
    
    local result = db.execute(migration)
    print("Migration result: " .. tostring(result))
    
    -- Проверяем, что поле удалено
    local sample = db.execute("SELECT * FROM products LIMIT 1")
    local sample_data = db.json_decode(sample)
    
    if sample_data[1].description == nil then
        print("✅ Field removed successfully")
        return true
    else
        print("❌ Field removal failed")
        return false
    end
end

local function test_add_validation_migration()
    print("\n=== Test 6: Add Validation Migration ===")
    
    -- Добавляем валидацию для поля price
    local migration = [[
        MIGRATE SCHEMA products
        ADD VALIDATION price {
            min = 0,
            max = 10000,
            type = "float"
        }
    ]]
    
    local result = db.execute(migration)
    print("Migration result: " .. tostring(result))
    
    -- Проверяем валидацию
    local success, err = pcall(function()
        return db.execute("INSERT INTO products VALUES {_id = 'invalid', title = 'Invalid', price = 20000}")
    end)
    
    if not success and string.find(err or "", "validation") then
        print("✅ Validation added and working")
        return true
    else
        print("❌ Validation not working correctly")
        return false
    end
end

local function test_rollback_migration()
    print("\n=== Test 7: Rollback Migration ===")
    
    -- Сохраняем текущее состояние
    local before_state = db.execute("SHOW SCHEMA STATUS")
    
    -- Откатываем последнюю миграцию
    local result = db.execute("ROLLBACK SCHEMA MIGRATION")
    print("Rollback result: " .. tostring(result))
    
    -- Проверяем, что validation убрана
    local success, err = pcall(function()
        return db.execute("INSERT INTO products VALUES {_id = 'rollback_test', title = 'Rollback Test', price = 20000}")
    end)
    
    if success then
        print("✅ Rollback successful - validation removed")
        return true
    else
        print("❌ Rollback failed")
        return false
    end
end

local function test_schema_migration_history()
    print("\n=== Test 8: Schema Migration History ===")
    
    local history = db.execute("SHOW SCHEMA MIGRATION HISTORY")
    local history_data = db.json_decode(history)
    
    print("Migration history:")
    for i, migration in ipairs(history_data) do
        print(string.format("  %d: %s - %s (applied: %s)",
            i, migration.id, migration.description,
            os.date("%Y-%m-%d %H:%M:%S", migration.applied_at / 1000)))
    end
    
    if #history_data >= 5 then
        print("✅ Migration history contains multiple entries")
        return true
    else
        print("⚠️ Migration history shorter than expected")
        return false
    end
end

local function test_lazy_schema_migration()
    print("\n=== Test 9: Lazy Schema Migration ===")
    
    -- Включаем ленивую миграцию
    db.execute("SET SCHEMA MIGRATION STRATEGY lazy")
    
    -- Меняем схему
    db.execute([[
        MIGRATE SCHEMA products
        ADD FIELD tags {
            type = "array",
            default = {}
        }
    ]])
    
    -- Существующие документы не должны иметь tags сразу
    local sample = db.execute("SELECT tags FROM products LIMIT 1")
    local sample_data = db.json_decode(sample)
    
    -- При первом чтении tags может отсутствовать
    -- При следующем чтении (после миграции) должно появиться
    
    print("✅ Lazy migration configured")
    return true
end

local function test_schema_migration_metrics()
    print("\n=== Test 10: Schema Migration Metrics ===")
    
    local metrics = db.execute("SHOW SCHEMA MIGRATION METRICS")
    local metrics_data = db.json_decode(metrics)
    
    print("Migration metrics:")
    for key, value in pairs(metrics_data) do
        print(string.format("  %s: %s", key, tostring(value)))
    end
    
    local required_fields = {
        "total_migrations",
        "applied_migrations",
        "pending_migrations",
        "current_version"
    }
    
    for _, field in ipairs(required_fields) do
        if metrics_data[field] == nil then
            print("❌ Missing metric: " .. field)
            return false
        end
    end
    
    print("✅ All required metrics present")
    return true
end

local function cleanup_schema()
    print("\n=== Cleanup ===")
    db.execute("DROP DATABASE IF EXISTS schema_test")
    print("Cleanup completed")
end

local function run_all_schema_migration_tests()
    print("╔══════════════════════════════════════════════════════════════╗")
    print("║     SCHEMA MIGRATION TESTS SUITE                              ║")
    print("╚══════════════════════════════════════════════════════════════╝")
    
    setup_schema_test()
    
    local results = {
        test_schema_version(),
        test_add_field_migration(),
        test_change_field_type_migration(),
        test_rename_field_migration(),
        test_remove_field_migration(),
        test_add_validation_migration(),
        test_rollback_migration(),
        test_schema_migration_history(),
        test_lazy_schema_migration(),
        test_schema_migration_metrics()
    }
    
    print("\n╔══════════════════════════════════════════════════════════════╗")
    print("║                     TEST RESULTS                              ║")
    print("╚══════════════════════════════════════════════════════════════╝")
    
    local passed = 0
    for i, result in ipairs(results) do
        local status = result and "✅ PASSED" or "⚠️ SKIPPED/FAILED"
        print(string.format("Test %d: %s", i, status))
        if result then passed = passed + 1 end
    end
    
    print(string.format("\nTotal: %d/%d tests passed", passed, #results))
    
    cleanup_schema()
    
    return passed == #results
end

return run_all_schema_migration_tests()