package controller

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"strings"
	"time"

	terdutv1alpha1 "git.ryuvia.com/niklas/terdut-operator/api/v1alpha1"
	"git.ryuvia.com/niklas/terdut-operator/internal/tdclient"
)

// reconcileEscalation applies spec.escalation as the team's whole ladder, or
// clears it when the field is absent (an empty ladder is the server's "none").
// The second return is an expected, reportable condition (a bad duration, an
// unknown user), the third a failure to retry.
func (r *TerdutTeamReconciler) reconcileEscalation(
	ctx context.Context, tc *tdclient.Client, team *terdutv1alpha1.TerdutTeam,
) (*teamError, error) {
	body, err := buildEscalationRequest(team.Spec.Escalation)
	if err != nil {
		return &teamError{reason: terdutv1alpha1.ReasonInvalidSpec, message: err.Error()}, nil
	}
	if err := tc.SetEscalation(ctx, team.Status.TeamID, body); err != nil {
		// The server resolves usernames; one it does not know is a state to
		// wait out (the person may be created later), not a failure.
		if se, ok := errors.AsType[*tdclient.StatusError](err); ok &&
			se.Code == http.StatusBadRequest && strings.HasPrefix(se.Message, "unknown user") {
			return &teamError{reason: terdutv1alpha1.ReasonUnknownUser, message: se.Message}, nil
		}
		return nil, fmt.Errorf("PUT /api/teams/%d/escalation: %w", team.Status.TeamID, err)
	}
	return nil, nil
}

func buildEscalationRequest(spec *terdutv1alpha1.EscalationSpec) (tdclient.SetEscalationRequest, error) {
	if spec == nil {
		return tdclient.SetEscalationRequest{Levels: []tdclient.EscalationLevelRequest{}}, nil
	}
	levels := make([]tdclient.EscalationLevelRequest, len(spec.Levels))
	for i, lvl := range spec.Levels {
		timeout, err := time.ParseDuration(lvl.Timeout)
		if err != nil || timeout <= 0 {
			return tdclient.SetEscalationRequest{}, fmt.Errorf("spec.escalation.levels[%d].timeout %q is not a positive duration", i, lvl.Timeout)
		}
		targets := make([]tdclient.EscalationTargetRequest, len(lvl.Targets))
		for j, t := range lvl.Targets {
			targets[j] = tdclient.EscalationTargetRequest{Kind: string(t.Kind), Username: t.Username}
		}
		levels[i] = tdclient.EscalationLevelRequest{
			Position:       int64(i + 1),
			TimeoutSeconds: int64(timeout.Seconds()),
			Targets:        targets,
		}
	}
	return tdclient.SetEscalationRequest{
		RepeatCount:   spec.RepeatCount,
		FallbackTopic: spec.FallbackTopic,
		Levels:        levels,
	}, nil
}

// reconcileDeadmanSwitches makes the team's switches on the server exactly
// spec.deadmanSwitches, matched by name (unique per team server-side): create
// what is missing, update what differs, delete what is not listed. In operator
// mode nobody else can add one, so anything extra is leftover to remove.
func (r *TerdutTeamReconciler) reconcileDeadmanSwitches(
	ctx context.Context, tc *tdclient.Client, team *terdutv1alpha1.TerdutTeam,
) (*teamError, error) {
	type want struct {
		spec    terdutv1alpha1.DeadmanSwitchSpec
		seconds int64
	}
	desired := make(map[string]want, len(team.Spec.DeadmanSwitches))
	for _, sw := range team.Spec.DeadmanSwitches {
		timeout, err := time.ParseDuration(sw.Timeout)
		if err != nil || timeout <= 0 {
			return &teamError{
				reason:  terdutv1alpha1.ReasonInvalidSpec,
				message: fmt.Sprintf("spec.deadmanSwitches[%q].timeout %q is not a positive duration", sw.Name, sw.Timeout),
			}, nil
		}
		desired[sw.Name] = want{spec: sw, seconds: int64(timeout.Seconds())}
	}

	existing, err := tc.ListDeadmanSwitches(ctx, team.Status.TeamID)
	if err != nil {
		return nil, fmt.Errorf("GET /api/teams/%d/deadman/switches: %w", team.Status.TeamID, err)
	}
	seen := make(map[string]bool, len(existing))
	for _, have := range existing {
		w, keep := desired[have.Name]
		if !keep {
			if err := tc.DeleteDeadmanSwitch(ctx, team.Status.TeamID, have.ID); err != nil {
				return nil, fmt.Errorf("DELETE deadman switch %q: %w", have.Name, err)
			}
			continue
		}
		seen[have.Name] = true
		severity := severityOrDefault(w.spec.Severity)
		if have.Matcher == w.spec.Matcher && have.TimeoutSeconds == w.seconds && have.Severity == severity {
			continue
		}
		if err := tc.UpdateDeadmanSwitch(ctx, team.Status.TeamID, have.ID, w.spec.Name, w.spec.Matcher, w.seconds, severity); err != nil {
			return nil, fmt.Errorf("PUT deadman switch %q: %w", have.Name, err)
		}
	}
	for _, sw := range team.Spec.DeadmanSwitches {
		if seen[sw.Name] {
			continue
		}
		w := desired[sw.Name]
		if _, err := tc.CreateDeadmanSwitch(ctx, team.Status.TeamID, sw.Name, sw.Matcher, w.seconds, severityOrDefault(sw.Severity)); err != nil {
			return nil, fmt.Errorf("POST deadman switch %q: %w", sw.Name, err)
		}
	}
	return nil, nil
}

func severityOrDefault(s string) string {
	if s == "" {
		return "critical"
	}
	return s
}