// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.

package checker

import (
	"context"
	"fmt"

	sdk "git.happydns.org/checker-sdk-go/checker"
)

// reachabilityRule reports per-IP reachability for one scheme.
type reachabilityRule struct {
	scheme string // "http" or "https"
	code   string
}

func (r *reachabilityRule) Name() string { return r.code }
func (r *reachabilityRule) Description() string {
	return fmt.Sprintf("Verifies that every probed IP accepts a %s connection on the standard port.", r.scheme)
}

func (r *reachabilityRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
	data, errSt := loadHTTPData(ctx, obs)
	if errSt != nil {
		return []sdk.CheckState{*errSt}
	}
	probes := probesByScheme(data.Probes, r.scheme)
	if len(probes) == 0 {
		return []sdk.CheckState{unknownState(r.code+".no_probes", "No probes were attempted.")}
	}

	var states []sdk.CheckState
	for _, p := range probes {
		switch {
		case !p.TCPConnected:
			states = append(states, sdk.CheckState{
				Status:  sdk.StatusCrit,
				Code:    r.code + ".unreachable",
				Subject: p.Address,
				Message: fmt.Sprintf("Cannot reach %s://%s on %s: %s", r.scheme, p.Host, p.Address, p.Error),
			})
		case p.StatusCode == 0:
			states = append(states, sdk.CheckState{
				Status:  sdk.StatusCrit,
				Code:    r.code + ".no_response",
				Subject: p.Address,
				Message: fmt.Sprintf("TCP open but no HTTP response from %s: %s", p.Address, p.Error),
			})
		case p.StatusCode >= 500:
			states = append(states, sdk.CheckState{
				Status:  sdk.StatusWarn,
				Code:    r.code + ".server_error",
				Subject: p.Address,
				Message: fmt.Sprintf("%s returned %d", p.Address, p.StatusCode),
			})
		}
	}
	if len(states) == 0 {
		return []sdk.CheckState{passState(r.code+".ok", fmt.Sprintf("All %s probes responded successfully.", r.scheme))}
	}
	return states
}