// FILE: lixenwraith/log/processor_test.go
package log

import (
	"encoding/json"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func TestLoggerHeartbeat(t *testing.T) {
	logger, tmpDir := createTestLogger(t)
	defer logger.Shutdown()

	cfg := logger.GetConfig()
	cfg.HeartbeatLevel = 3 // All heartbeats
	cfg.HeartbeatIntervalS = 1
	err := logger.ApplyConfig(cfg)
	require.NoError(t, err)

	// Wait for heartbeats
	time.Sleep(1500 * time.Millisecond)
	logger.Flush(time.Second)

	content, err := os.ReadFile(filepath.Join(tmpDir, "log.log"))
	require.NoError(t, err)

	// Check for heartbeat content
	assert.Contains(t, string(content), "PROC")
	assert.Contains(t, string(content), "DISK")
	assert.Contains(t, string(content), "SYS")
	assert.Contains(t, string(content), "uptime_hours")
	assert.Contains(t, string(content), "processed_logs")
	assert.Contains(t, string(content), "num_goroutine")
}

func TestDroppedLogs(t *testing.T) {
	logger := NewLogger()

	cfg := DefaultConfig()
	cfg.Directory = t.TempDir()
	cfg.BufferSize = 1         // Very small buffer
	cfg.FlushIntervalMs = 10   // Fast processing
	cfg.HeartbeatLevel = 1     // Enable proc heartbeat
	cfg.HeartbeatIntervalS = 1 // Fast heartbeat

	err := logger.ApplyConfig(cfg)
	require.NoError(t, err)

	err = logger.Start()
	require.NoError(t, err)
	defer logger.Shutdown()

	// Flood to guarantee drops
	for i := 0; i < 100; i++ {
		logger.Info("flood", i)
	}

	// Wait for first heartbeat
	time.Sleep(1500 * time.Millisecond)

	// Flood again
	for i := 0; i < 50; i++ {
		logger.Info("flood2", i)
	}

	// Wait for second heartbeat
	time.Sleep(1000 * time.Millisecond)
	logger.Flush(time.Second)

	// Read log file and verify heartbeats
	content, err := os.ReadFile(filepath.Join(cfg.Directory, "log.log"))
	require.NoError(t, err)

	lines := strings.Split(string(content), "\n")
	foundTotal := false
	foundInterval := false

	for _, line := range lines {
		if strings.Contains(line, "PROC") {
			if strings.Contains(line, "total_dropped_logs") {
				foundTotal = true
			}
			if strings.Contains(line, "dropped_since_last") {
				foundInterval = true
			}
		}
	}

	assert.True(t, foundTotal, "Expected PROC heartbeat with total_dropped_logs")
	assert.True(t, foundInterval, "Expected PROC heartbeat with dropped_since_last")
}

func TestAdaptiveDiskCheck(t *testing.T) {
	logger, _ := createTestLogger(t)
	defer logger.Shutdown()

	cfg := logger.GetConfig()
	cfg.EnableAdaptiveInterval = true
	cfg.DiskCheckIntervalMs = 100
	cfg.MinCheckIntervalMs = 50
	cfg.MaxCheckIntervalMs = 500
	err := logger.ApplyConfig(cfg)
	require.NoError(t, err)

	// Generate varying log rates and verify no panic
	for i := 0; i < 10; i++ {
		logger.Info("adaptive test", i)
		time.Sleep(10 * time.Millisecond)
	}

	// Burst
	for i := 0; i < 100; i++ {
		logger.Info("burst", i)
	}

	logger.Flush(time.Second)
}

func TestDroppedLogRecoveryOnDroppedHeartbeat(t *testing.T) {
	logger := NewLogger()

	cfg := DefaultConfig()
	cfg.Directory = t.TempDir()
	cfg.BufferSize = 10        // Small buffer
	cfg.HeartbeatLevel = 1     // Enable proc heartbeat
	cfg.HeartbeatIntervalS = 1 // Fast heartbeat
	cfg.Format = "json"        // Use JSON for easy parsing

	err := logger.ApplyConfig(cfg)
	require.NoError(t, err)

	err = logger.Start()
	require.NoError(t, err)
	defer logger.Shutdown()

	// 1. Flood the logger to guarantee drops. Let's aim to drop exactly 50 logs.
	const floodCount = 50
	for i := 0; i < int(cfg.BufferSize)+floodCount; i++ {
		logger.Info("flood", i)
	}

	// Wait for the first heartbeat to be generated. It will carry the count of ~50 drops.
	time.Sleep(1100 * time.Millisecond)

	// 2. Immediately put the logger into a "disk full" state.
	// This will cause the processor to drop the first heartbeat record.
	diskFullCfg := logger.GetConfig()
	diskFullCfg.MinDiskFreeKB = 9999999999
	err = logger.ApplyConfig(diskFullCfg)
	require.NoError(t, err)
	// Force a disk check to ensure the state is updated to not OK.
	logger.performDiskCheck(true)
	assert.False(t, logger.state.DiskStatusOK.Load(), "Disk status should be not OK")

	// 3. Now, "fix" the disk so the next heartbeat can be written successfully.
	diskOKCfg := logger.GetConfig()
	diskOKCfg.MinDiskFreeKB = 0
	err = logger.ApplyConfig(diskOKCfg)
	require.NoError(t, err)
	logger.performDiskCheck(true) // Ensure state is updated back to OK.
	assert.True(t, logger.state.DiskStatusOK.Load(), "Disk status should be OK")

	// 4. Wait for the second heartbeat to be generated and written to the file.
	time.Sleep(1100 * time.Millisecond)
	logger.Flush(time.Second)

	// 5. Verify the log file content.
	content, err := os.ReadFile(filepath.Join(cfg.Directory, "log.log"))
	require.NoError(t, err)

	var foundHeartbeat bool
	var intervalDropCount, totalDropCount float64
	lines := strings.Split(string(content), "\n")

	for _, line := range lines {
		// Find the last valid heartbeat with drop stats.
		if strings.Contains(line, `"level":"PROC"`) && strings.Contains(line, "dropped_since_last") {
			foundHeartbeat = true
			var entry map[string]interface{}
			err := json.Unmarshal([]byte(line), &entry)
			require.NoError(t, err, "Failed to parse heartbeat log line: %s", line)

			fields := entry["fields"].([]interface{})
			for i := 0; i < len(fields)-1; i += 2 {
				if key, ok := fields[i].(string); ok {
					if key == "dropped_since_last" {
						intervalDropCount, _ = fields[i+1].(float64)
					}
					if key == "total_dropped_logs" {
						totalDropCount, _ = fields[i+1].(float64)
					}
				}
			}
		}
	}

	require.True(t, foundHeartbeat, "Did not find the final heartbeat with drop stats")

	// ASSERT THE CURRENT BEHAVIOR:
	// The 'dropped_since_last' count from the first heartbeat (~50) was lost when that heartbeat was dropped.
	// The only new drop in the next interval was the heartbeat record itself.
	assert.Equal(t, float64(1), intervalDropCount, "The interval drop count should only reflect the single dropped heartbeat from the previous interval.")

	// The 'total_dropped_logs' counter should be accurate, reflecting the initial flood (~50) + the one dropped heartbeat.
	assert.True(t, totalDropCount >= float64(floodCount), "Total drop count should be at least the number of flooded logs plus the dropped heartbeat.")
}