package tools

import (
	"context"
	"fmt"

	"github.com/modelcontextprotocol/go-sdk/mcp"
)

func registerMonitoringTools(s *mcp.Server) {
	// usage
	s.AddTool(&mcp.Tool{
		Name:        "usage",
		Description: "Get CPU/RAM/Disk usage summary",
		InputSchema: schema(map[string]any{
			"target": strProps("Connection alias (default: primary)", false),
		}, nil),
	}, usageHandler)

	// ps
	s.AddTool(&mcp.Tool{
		Name:        "ps",
		Description: "List top processes sorted by CPU or memory",
		InputSchema: schema(map[string]any{
			"sort_by": strProps("Sort field (default: cpu)", false, "cpu", "mem"),
			"limit":   intProps("Number of processes to show (default: 10)", false),
			"target":  strProps("Connection alias (default: primary)", false),
		}, nil),
	}, psHandler)

	// logs
	s.AddTool(&mcp.Tool{
		Name:        "logs",
		Description: "Read the tail of a log file",
		InputSchema: schema(map[string]any{
			"path":   strProps("Path to log file", true),
			"lines":  intProps("Number of lines to read (default: 50, max: 500)", false),
			"grep":   strProps("Optional filter pattern", false),
			"target": strProps("Connection alias (default: primary)", false),
		}, []string{"path"}),
	}, logsHandler)

	// journal_read
	s.AddTool(&mcp.Tool{
		Name:        "journal_read",
		Description: "Read system logs (journalctl/syslog)",
		InputSchema: schema(map[string]any{
			"service":  strProps("Service name to filter (e.g., nginx, sshd)", false),
			"since":    strProps("Time filter (e.g., '1 hour ago')", false),
			"lines":    intProps("Number of lines (default: 100, max: 500)", false),
			"priority": strProps("Minimum log priority level", false, "emerg", "alert", "crit", "err", "warning", "notice", "info", "debug"),
			"target":   strProps("Connection alias (default: primary)", false),
		}, nil),
	}, journalReadHandler)

	// dmesg_read
	s.AddTool(&mcp.Tool{
		Name:        "dmesg_read",
		Description: "Read kernel ring buffer (dmesg)",
		InputSchema: schema(map[string]any{
			"grep":   strProps("Optional pattern to filter messages", false),
			"lines":  intProps("Number of lines (default: 100)", false),
			"target": strProps("Connection alias (default: primary)", false),
		}, nil),
	}, dmesgReadHandler)

	// diagnose_system
	s.AddTool(&mcp.Tool{
		Name:        "diagnose_system",
		Description: "One-click SRE health check: load, OOM, disk, failed services",
		InputSchema: schema(map[string]any{
			"target": strProps("Connection alias (default: primary)", false),
		}, nil),
	}, diagnoseHandler)

	// list_services
	s.AddTool(&mcp.Tool{
		Name:        "list_services",
		Description: "List system services (systemd/OpenRC)",
		InputSchema: schema(map[string]any{
			"failed_only": boolProps("Show only failed services", false),
			"target":      strProps("Connection alias (default: primary)", false),
		}, nil),
	}, listServicesHandler)
}

func usageHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	target := getString(requestArgs(req), "target", "primary")
	cmd := `
echo "=== LOAD AVERAGE ==="
uptime 2>/dev/null

echo ""
echo "=== MEMORY ==="
free -h 2>/dev/null || top -l 1 -s 0 2>/dev/null | grep -i phys || cat /proc/meminfo 2>/dev/null | head -5

echo ""
echo "=== DISK (all mounts) ==="
df -hP 2>/dev/null
`
	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}

func psHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	args := requestArgs(req)
	sortBy := getString(args, "sort_by", "cpu")
	limit := getInt(args, "limit", 10)
	target := getString(args, "target", "primary")

	if limit > 50 {
		limit = 50
	}
	sortCol := "3"
	if sortBy == "mem" {
		sortCol = "4"
	}
	cmd := fmt.Sprintf("ps -eo pid,user,%%cpu,%%mem,comm | awk 'NR==1{print} NR>1{print | \"sort -k%s -rn\"}' | head -n %d", sortCol, limit+1)
	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}

func logsHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	args := requestArgs(req)
	path, _ := requireString(args, "path")
	lines := getInt(args, "lines", 50)
	grep := getString(args, "grep", "")
	target := getString(args, "target", "primary")

	if lines > 500 {
		lines = 500
	}
	cmd := fmt.Sprintf("tail -n %d %s", lines, shellQuote(path))
	if grep != "" {
		cmd += fmt.Sprintf(" | grep %s", shellQuote(grep))
	}
	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}

func journalReadHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	args := requestArgs(req)
	service := getString(args, "service", "")
	since := getString(args, "since", "")
	lines := getInt(args, "lines", 100)
	priority := getString(args, "priority", "")
	target := getString(args, "target", "primary")

	if lines > 500 {
		lines = 500
	}
	checkCmd := "command -v journalctl >/dev/null 2>&1 && echo 'systemd' || echo 'syslog'"
	checkOutput, err := m.Execute(ctx, checkCmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}

	var cmd string
	if containsString(checkOutput, "systemd") {
		cmd = "journalctl --no-pager"
		if service != "" {
			cmd += fmt.Sprintf(" -u %s", shellQuote(service))
		}
		if since != "" {
			cmd += fmt.Sprintf(" --since %s", shellQuote(since))
		}
		if priority != "" {
			cmd += fmt.Sprintf(" -p %s", shellQuote(priority))
		}
		cmd += fmt.Sprintf(" -n %d 2>/dev/null", lines)
	} else {
		cmd = fmt.Sprintf("cat /var/log/syslog /var/log/messages /var/log/system.log 2>/dev/null | tail -n %d", lines)
		if service != "" {
			cmd += fmt.Sprintf(" | grep -i %s", shellQuote(service))
		}
	}
	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}

func dmesgReadHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	args := requestArgs(req)
	grep := getString(args, "grep", "")
	lines := getInt(args, "lines", 100)
	target := getString(args, "target", "primary")

	if lines > 500 {
		lines = 500
	}
	cmd := "dmesg --time-format iso 2>/dev/null || dmesg 2>/dev/null"
	if grep != "" {
		cmd += fmt.Sprintf(" | grep -i %s", shellQuote(grep))
	}
	cmd += fmt.Sprintf(" | tail -n %d", lines)

	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}

func diagnoseHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	target := getString(requestArgs(req), "target", "primary")
	cmd := `
echo "=== SYSTEM HEALTH DIAGNOSTIC ==="
echo ""

echo "--- LOAD AVERAGE ---"
LOAD=$(uptime 2>/dev/null | awk -F'load average[s]?: ' '{print $2}' | awk -F'[, ]' '{print $1}')
CPUS=$(nproc 2>/dev/null || sysctl -n hw.ncpu 2>/dev/null || getconf _NPROCESSORS_ONLN 2>/dev/null || echo 1)
echo "Load (1min): $LOAD (CPUs: $CPUS)"
if echo "$LOAD $CPUS" | awk '{if ($1 > $2 * 2) exit 0; else exit 1}'; then
  echo "WARNING: High load detected!"
fi
echo ""

echo "--- TOP CPU CONSUMERS ---"
ps -eo pid,user,%cpu,%mem,comm | awk 'NR==1{print} NR>1{print | "sort -k3 -rn"}' | head -n 6
echo ""

echo "--- OOM EVENTS ---"
OOM=$(dmesg 2>/dev/null | grep -i 'out of memory' | tail -n 3)
if [ -n "$OOM" ]; then
  echo "$OOM"
  echo "WARNING: OOM events found!"
else
  echo "No OOM events in dmesg"
fi
echo ""

echo "--- DISK PRESSURE (>=80%) ---"
df -hP 2>/dev/null | awk 'NR==1{print; next} {c=$5; sub(/%/,"",c); m=(c+0>=80 ? "  <<ALERT" : ""); print $0 m}'
echo ""

echo "--- FAILED SERVICES ---"
if command -v systemctl >/dev/null 2>&1; then
  FAILED=$(systemctl --failed --no-legend --no-pager 2>/dev/null | head -n 5)
  if [ -n "$FAILED" ]; then
    echo "$FAILED"
  else
    echo "No failed services"
  fi
elif command -v rc-status >/dev/null 2>&1; then
  rc-status --crashed 2>/dev/null | head -n 5 || echo "No crashed services"
else
  echo "Init system not detected"
fi

echo ""
echo "=== END DIAGNOSTIC ==="
`
	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}

func listServicesHandler(ctx context.Context, req *mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	m := manager()
	if m == nil {
		return errorResult("no SSH manager initialized"), nil
	}
	args := requestArgs(req)
	failedOnly := getBool(args, "failed_only", false)
	target := getString(args, "target", "primary")

	var cmd string
	if failedOnly {
		cmd = `if command -v systemctl >/dev/null 2>&1; then systemctl --failed --no-pager 2>/dev/null; elif command -v rc-status >/dev/null 2>&1; then rc-status --crashed 2>/dev/null; elif command -v launchctl >/dev/null 2>&1; then launchctl list 2>/dev/null | head -50; else echo "No supported init system detected"; fi`
	} else {
		cmd = `if command -v systemctl >/dev/null 2>&1; then systemctl list-units --type=service --no-pager 2>/dev/null | head -50; elif command -v rc-status >/dev/null 2>&1; then rc-status 2>/dev/null; elif command -v launchctl >/dev/null 2>&1; then launchctl list 2>/dev/null | head -50; elif [ -x /usr/sbin/service ]; then service -e 2>/dev/null | head -50; else echo "No supported init system detected"; fi`
	}
	output, err := m.Execute(ctx, cmd, target)
	if err != nil {
		return errorResult(err.Error()), nil
	}
	return textResult(output), nil
}