package main

import (
	"encoding/json"
	"fmt"
	"log"
	"math"
	"os"
	"strings"
	"time"
)

const dataFile = "/data/chu_stats.json"

type CHUStats struct {
	GeneratedAt         time.Time `json:"generated_at"`
	HospitalName        string    `json:"hospital_name"`
	Date                string    `json:"date"`
	BedsTotal           int       `json:"beds_total"`
	BedsOccupied        int       `json:"beds_occupied"`
	OccupancyRate       float64   `json:"occupancy_rate"`
	PatientsAdmitted    int       `json:"patients_admitted"`
	PatientsDischarge   int       `json:"patients_discharged"`
	EmergencyVisits     int       `json:"emergency_visits"`
	AvgERWaitMinutes    int       `json:"avg_er_wait_minutes"`
	SurgeriesPerformed  int       `json:"surgeries_performed"`
	ICUBeds             int       `json:"icu_beds"`
	ICUOccupied         int       `json:"icu_occupied"`
	MortalityRate       float64   `json:"mortality_rate"`
	InfectionRate       float64   `json:"infection_rate"`
	StaffPresent        int       `json:"staff_present"`
	StaffRequired       int       `json:"staff_required"`
	PatientSatisfaction float64   `json:"patient_satisfaction"`
}

type Check struct {
	Indicator  string  `json:"indicator"`
	Value      float64 `json:"value"`
	Unit       string  `json:"unit"`
	Threshold  string  `json:"threshold"`
	Conformant bool    `json:"conformant"`
	Severity   string  `json:"severity"`
	Message    string  `json:"message"`
}

type Analysis struct {
	AnalyzedAt     time.Time `json:"analyzed_at"`
	HospitalName   string    `json:"hospital_name"`
	StatsDate      string    `json:"stats_date"`
	Conformant     bool      `json:"conformant"`
	Score          int       `json:"score"`
	PassingChecks  int       `json:"passing_checks"`
	TotalChecks    int       `json:"total_checks"`
	CriticalAlerts int       `json:"critical_alerts"`
	WarningAlerts  int       `json:"warning_alerts"`
	Checks         []Check   `json:"checks"`
	Summary        string    `json:"summary"`
}

func round2(v float64) float64 {
	return math.Round(v*100) / 100
}

func analyze(s CHUStats) Analysis {
	var checks []Check

	occ := Check{Indicator: "Taux d'occupation des lits", Value: s.OccupancyRate, Unit: "%", Threshold: "< 85%"}
	switch {
	case s.OccupancyRate < 85:
		occ.Conformant, occ.Severity, occ.Message = true, "ok", "Taux d'occupation normal"
	case s.OccupancyRate < 95:
		occ.Conformant, occ.Severity, occ.Message = false, "warning", "Taux d'occupation élevé, risque de saturation"
	default:
		occ.Conformant, occ.Severity, occ.Message = false, "critical", "Saturation critique des lits hospitaliers"
	}
	checks = append(checks, occ)

	er := Check{Indicator: "Temps d'attente aux urgences", Value: float64(s.AvgERWaitMinutes), Unit: "min", Threshold: "< 60 min"}
	switch {
	case s.AvgERWaitMinutes < 60:
		er.Conformant, er.Severity, er.Message = true, "ok", "Temps d'attente aux urgences acceptable"
	case s.AvgERWaitMinutes < 120:
		er.Conformant, er.Severity, er.Message = false, "warning", "Temps d'attente aux urgences trop long"
	default:
		er.Conformant, er.Severity, er.Message = false, "critical", "Saturation critique des urgences"
	}
	checks = append(checks, er)

	icuRate := round2(float64(s.ICUOccupied) / float64(s.ICUBeds) * 100)
	icu := Check{Indicator: "Taux d'occupation ICU", Value: icuRate, Unit: "%", Threshold: "< 85%"}
	switch {
	case icuRate < 85:
		icu.Conformant, icu.Severity, icu.Message = true, "ok", "Capacité de réanimation suffisante"
	case icuRate < 95:
		icu.Conformant, icu.Severity, icu.Message = false, "warning", "Taux d'occupation ICU élevé"
	default:
		icu.Conformant, icu.Severity, icu.Message = false, "critical", "Réanimation en situation critique"
	}
	checks = append(checks, icu)

	mort := Check{Indicator: "Taux de mortalité hospitalière", Value: s.MortalityRate, Unit: "%", Threshold: "< 2%"}
	switch {
	case s.MortalityRate < 2.0:
		mort.Conformant, mort.Severity, mort.Message = true, "ok", "Taux de mortalité dans les normes"
	case s.MortalityRate < 4.0:
		mort.Conformant, mort.Severity, mort.Message = false, "warning", "Taux de mortalité supérieur au seuil recommandé"
	default:
		mort.Conformant, mort.Severity, mort.Message = false, "critical", "Taux de mortalité critique — investigation requise"
	}
	checks = append(checks, mort)

	infect := Check{Indicator: "Taux d'infection nosocomiale", Value: s.InfectionRate, Unit: "%", Threshold: "< 5%"}
	switch {
	case s.InfectionRate < 5.0:
		infect.Conformant, infect.Severity, infect.Message = true, "ok", "Taux d'infection nosocomiale acceptable"
	case s.InfectionRate < 8.0:
		infect.Conformant, infect.Severity, infect.Message = false, "warning", "Taux d'infection nosocomiale préoccupant"
	default:
		infect.Conformant, infect.Severity, infect.Message = false, "critical", "Risque infectieux critique — mesures d'urgence requises"
	}
	checks = append(checks, infect)

	staffRate := round2(float64(s.StaffPresent) / float64(s.StaffRequired) * 100)
	staff := Check{Indicator: "Taux de couverture du personnel", Value: staffRate, Unit: "%", Threshold: ">= 80%"}
	switch {
	case staffRate >= 80:
		staff.Conformant, staff.Severity, staff.Message = true, "ok", "Personnel suffisant"
	case staffRate >= 70:
		staff.Conformant, staff.Severity, staff.Message = false, "warning", "Manque de personnel, vigilance requise"
	default:
		staff.Conformant, staff.Severity, staff.Message = false, "critical", "Sous-effectif critique"
	}
	checks = append(checks, staff)

	sat := Check{Indicator: "Satisfaction des patients", Value: s.PatientSatisfaction, Unit: "/ 5", Threshold: ">= 3.5 / 5"}
	switch {
	case s.PatientSatisfaction >= 3.5:
		sat.Conformant, sat.Severity, sat.Message = true, "ok", "Satisfaction des patients satisfaisante"
	case s.PatientSatisfaction >= 3.0:
		sat.Conformant, sat.Severity, sat.Message = false, "warning", "Satisfaction des patients insuffisante"
	default:
		sat.Conformant, sat.Severity, sat.Message = false, "critical", "Satisfaction des patients très mauvaise"
	}
	checks = append(checks, sat)

	passing, critical, warning := 0, 0, 0
	for _, c := range checks {
		if c.Conformant {
			passing++
		}
		switch c.Severity {
		case "critical":
			critical++
		case "warning":
			warning++
		}
	}
	total := len(checks)
	score := passing * 100 / total

	return Analysis{
		AnalyzedAt:     time.Now().UTC(),
		HospitalName:   s.HospitalName,
		StatsDate:      s.Date,
		Conformant:     passing == total,
		Score:          score,
		PassingChecks:  passing,
		TotalChecks:    total,
		CriticalAlerts: critical,
		WarningAlerts:  warning,
		Checks:         checks,
		Summary: fmt.Sprintf(
			"%d/%d indicateurs conformes (score: %d%%) — %d alerte(s) critique(s), %d avertissement(s)",
			passing, total, score, critical, warning,
		),
	}
}

func main() {
	for i := range []int{0, 1} {
		data, err := os.ReadFile(strings.ReplaceAll(dataFile, "stats", "stats"+fmt.Sprintf("%v", i)))
		if err != nil {
			if os.IsNotExist(err) {
				log.Fatalf("stats file not found at %s — run chu-stats-generator first", dataFile)
			}
			log.Fatalf("failed to read stats file: %v", err)
		}

		var stats CHUStats
		if err := json.Unmarshal(data, &stats); err != nil {
			log.Fatalf("failed to parse stats file: %v", err)
		}

		analysis := analyze(stats)

		result, err := json.MarshalIndent(analysis, "", "  ")
		if err != nil {
			log.Fatalf("failed to marshal analysis: %v", err)
		}

		log.Printf("Analysis complete: %s", analysis.Summary)
		fmt.Println(string(result))
	}
}