-- Unit tests for caching utilities
local cache = require('notex.utils.cache')

describe("cache utilities", function()

  before_each(function()
    -- Reset cache before each test
    cache.init({
      memory = {enabled = true, max_size = 10},
      lru = {enabled = true, max_size = 5},
      timed = {enabled = true, default_ttl = 1}
    })
  end)

  after_each(function()
    cache.cleanup()
  end)

  describe("memory cache", function()
    it("should store and retrieve values", function()
      local ok = cache.memory_set("test_key", "test_value")
      assert.is_true(ok)

      local value = cache.memory_get("test_key")
      assert.equals("test_value", value)
    end)

    it("should return nil for non-existent keys", function()
      local value = cache.memory_get("non_existent")
      assert.is_nil(value)
    end)

    it("should handle cache size limits", function()
      -- Fill cache beyond max size
      for i = 1, 15 do
        cache.memory_set("key_" .. i, "value_" .. i)
      end

      -- Should still be able to set new values (eviction happens)
      local ok = cache.memory_set("new_key", "new_value")
      assert.is_true(ok)

      -- Should still be able to get some values
      local value = cache.memory_get("new_key")
      assert.equals("new_value", value)
    end)
  end)

  describe("LRU cache", function()
    it("should store and retrieve values with LRU eviction", function()
      cache.lru_set("key1", "value1")
      cache.lru_set("key2", "value2")
      cache.lru_set("key3", "value3")

      -- Access key1 to make it most recently used
      local value = cache.lru_get("key1")
      assert.equals("value1", value)

      -- Add more items to trigger eviction
      cache.lru_set("key4", "value4")
      cache.lru_set("key5", "value5")
      cache.lru_set("key6", "value6") -- Should evict key2 (least recently used)

      -- key2 should be evicted, key1 should still exist
      assert.is_nil(cache.lru_get("key2"))
      assert.equals("value1", cache.lru_get("key1"))
    end)

    it("should update access order on get", function()
      cache.lru_set("key1", "value1")
      cache.lru_set("key2", "value2")

      -- Get key1 to make it most recently used
      cache.lru_get("key1")

      -- Fill cache to evict
      cache.lru_set("key3", "value3")
      cache.lru_set("key4", "value4")
      cache.lru_set("key5", "value4")
      cache.lru_set("key6", "value4") -- Should evict key2

      assert.is_not_nil(cache.lru_get("key1")) -- Should still exist
      assert.is_nil(cache.lru_get("key2")) -- Should be evicted
    end)
  end)

  describe("timed cache", function()
    it("should store values with TTL", function()
      cache.timed_set("test_key", "test_value", 2) -- 2 second TTL

      local value = cache.timed_get("test_key")
      assert.equals("test_value", value)
    end)

    it("should expire values after TTL", function()
      cache.timed_set("test_key", "test_value", 1) -- 1 second TTL

      -- Should be available immediately
      local value = cache.timed_get("test_key")
      assert.equals("test_value", value)

      -- Wait for expiration
      vim.defer_fn(function()
        value = cache.timed_get("test_key")
        assert.is_nil(value)
      end, 1100)
    end)

    it("should use default TTL when not specified", function()
      cache.timed_set("test_key", "test_value")

      local value = cache.timed_get("test_key")
      assert.equals("test_value", value)
    end)
  end)

  describe("generic cache operations", function()
    it("should set and get with specified cache type", function()
      local ok = cache.set("test_key", "test_value", "memory")
      assert.is_true(ok)

      local value = cache.get("test_key", "memory")
      assert.equals("test_value", value)
    end)

    it("should default to memory cache", function()
      local ok = cache.set("test_key", "test_value")
      assert.is_true(ok)

      local value = cache.get("test_key")
      assert.equals("test_value", value)
    end)

    it("should handle unknown cache types", function()
      local ok = cache.set("test_key", "test_value", "unknown")
      assert.is_false(ok)

      local value = cache.get("test_key", "unknown")
      assert.is_nil(value)
    end)
  end)

  describe("get_or_set", function()
    it("should return cached value when exists", function()
      cache.set("test_key", "cached_value")

      local value = cache.get_or_set("test_key", function()
        return "computed_value"
      end)

      assert.equals("cached_value", value)
    end)

    it("should compute and cache value when not exists", function()
      local call_count = 0
      local value = cache.get_or_set("test_key", function()
        call_count = call_count + 1
        return "computed_value"
      end)

      assert.equals("computed_value", value)
      assert.equals(1, call_count)

      -- Second call should use cached value
      value = cache.get_or_set("test_key", function()
        call_count = call_count + 1
        return "new_value"
      end)

      assert.equals("computed_value", value)
      assert.equals(1, call_count) -- Should not be called again
    end)

    it("should handle computation errors", function()
      assert.has_error(function()
        cache.get_or_set("test_key", function()
          error("Computation failed")
        end)
      end)
    end)
  end)

  describe("multi_get", function()
    it("should try multiple cache types in order", function()
      cache.set("test_key", "memory_value", "memory")
      cache.set("test_key", "lru_value", "lru")

      local value, cache_type = cache.multi_get("test_key", {"lru", "memory"})
      assert.equals("lru_value", value)
      assert.equals("lru", cache_type)

      -- Should try memory if lru doesn't have it
      cache.invalidate("test_key", "lru")
      value, cache_type = cache.multi_get("test_key", {"lru", "memory"})
      assert.equals("memory_value", value)
      assert.equals("memory", cache_type)
    end)

    it("should return nil when not found in any cache", function()
      local value = cache.multi_get("non_existent", {"memory", "lru", "timed"})
      assert.is_nil(value)
    end)

    it("should use default cache types when not specified", function()
      cache.set("test_key", "memory_value", "memory")

      local value = cache.multi_get("test_key")
      assert.equals("memory_value", value)
    end)
  end)

  describe("invalidate", function()
    it("should invalidate from specific cache type", function()
      cache.set("test_key", "test_value", "memory")
      cache.set("test_key", "test_value", "lru")

      cache.invalidate("test_key", "memory")

      assert.is_nil(cache.get("test_key", "memory"))
      assert.equals("test_value", cache.get("test_key", "lru"))
    end)

    it("should invalidate from all caches when type not specified", function()
      cache.set("test_key", "test_value", "memory")
      cache.set("test_key", "test_value", "lru")
      cache.set("test_key", "test_value", "timed")

      cache.invalidate("test_key")

      assert.is_nil(cache.get("test_key", "memory"))
      assert.is_nil(cache.get("test_key", "lru"))
      assert.is_nil(cache.get("test_key", "timed"))
    end)
  end)

  describe("clear_all", function()
    it("should clear all caches", function()
      cache.set("key1", "value1", "memory")
      cache.set("key2", "value2", "lru")
      cache.set("key3", "value3", "timed")

      cache.clear_all()

      assert.is_nil(cache.get("key1", "memory"))
      assert.is_nil(cache.get("key2", "lru"))
      assert.is_nil(cache.get("key3", "timed"))
    end)

    it("should reset metrics", function()
      -- Generate some metrics
      cache.set("test", "value")
      cache.get("test")
      cache.get("non_existent")

      local stats_before = cache.get_stats()
      assert.is_true(stats_before.metrics.hits > 0)
      assert.is_true(stats_before.metrics.misses > 0)

      cache.clear_all()

      local stats_after = cache.get_stats()
      assert.equals(0, stats_after.metrics.hits)
      assert.equals(0, stats_after.metrics.misses)
    end)
  end)

  describe("get_stats", function()
    it("should return comprehensive statistics", function()
      -- Generate some activity
      cache.set("test1", "value1")
      cache.set("test2", "value2")
      cache.get("test1")
      cache.get("non_existent")

      local stats = cache.get_stats()

      assert.is_not_nil(stats.metrics)
      assert.is_not_nil(stats.sizes)
      assert.is_not_nil(stats.config)

      assert.is_true(stats.metrics.sets >= 2)
      assert.is_true(stats.metrics.hits >= 1)
      assert.is_true(stats.metrics.misses >= 1)
      assert.is_not_nil(stats.metrics.hit_ratio)
    end)

    it("should calculate hit ratio correctly", function()
      -- Generate known metrics
      cache.set("test", "value")
      cache.get("test") -- hit
      cache.get("test") -- hit
      cache.get("non_existent") -- miss

      local stats = cache.get_stats()
      -- Should be 2 hits out of 3 total requests = ~0.67
      assert.is_true(stats.metrics.hit_ratio > 0.6)
      assert.is_true(stats.metrics.hit_ratio < 0.7)
    end)
  end)

  describe("configuration", function()
    it("should initialize with custom configuration", function()
      cache.init({
        memory = {enabled = false},
        lru = {enabled = true, max_size = 20},
        timed = {enabled = true, default_ttl = 10}
      })

      -- Memory cache should be disabled
      local ok = cache.memory_set("test", "value")
      assert.is_false(ok)

      -- LRU cache should work with new size
      ok = cache.lru_set("test", "value")
      assert.is_true(ok)

      -- Timed cache should work with new TTL
      cache.timed_set("test2", "value")
      local value = cache.timed_get("test2")
      assert.equals("value", value)
    end)
  end)

end)