package handler

import (
	"context"
	"net/http"
	"sort"
	"time"

	"github.com/gin-gonic/gin"
)

type HealthHandler struct {
	startedAt time.Time
	checks    map[string]ReadinessCheck
}

type ReadinessCheck func(context.Context) error

func NewHealthHandler(checks map[string]ReadinessCheck) *HealthHandler {
	return &HealthHandler{startedAt: time.Now(), checks: checks}
}

func (h *HealthHandler) Live(c *gin.Context) {
	c.JSON(http.StatusOK, gin.H{
		"status":     "ok",
		"service":    "hfb-api",
		"started_at": h.startedAt.Format(time.RFC3339),
	})
}

func (h *HealthHandler) Ready(c *gin.Context) {
	ctx, cancel := context.WithTimeout(c.Request.Context(), 2*time.Second)
	defer cancel()

	names := make([]string, 0, len(h.checks))
	for name := range h.checks {
		names = append(names, name)
	}
	sort.Strings(names)

	ready := true
	dependencies := make(map[string]string, len(names))
	for _, name := range names {
		check := h.checks[name]
		if check == nil || check(ctx) != nil {
			dependencies[name] = "unavailable"
			ready = false
			continue
		}
		dependencies[name] = "ok"
	}

	statusCode := http.StatusOK
	status := "ok"
	if !ready {
		statusCode = http.StatusServiceUnavailable
		status = "unavailable"
	}
	c.JSON(statusCode, gin.H{
		"status":       status,
		"service":      "hfb-api",
		"started_at":   h.startedAt.Format(time.RFC3339),
		"dependencies": dependencies,
	})
}