package engine

import (
	"context"
	"fmt"
	"os"
	"strings"
	"sync"
	"time"

	"jarl/internal/model"
	"jarl/internal/render"
	"jarl/internal/validate"
)

// namedCheckTTL is how long the result of checking named's running
// configuration is kept when nothing changed.
const namedCheckTTL = 10 * time.Minute

// namedCheck caches the warnings of named-checkconf on the configuration
// named runs, keyed by what it depends on.
type namedCheck struct {
	mu       sync.Mutex
	key      string
	at       time.Time
	problems []validate.Problem
}

// namedProblems runs named-checkconf on the configuration named runs
// (without loading zones, which is quick) and returns what it reports as
// problems. An apply shows these too, but they are named's own checks,
// which Jarl doesn't repeat ("both recursion no and allow-recursion
// active"): the dashboard lists them with Jarl's so they don't go unseen
// after the apply. The result is reused while the deployed files and
// named's main file are unchanged.
func (e *Engine) namedProblems(ctx context.Context, st *model.State, deployed map[string]*model.DeployedFile) []validate.Problem {
	if e.tools == nil || e.cfg.SkipCheck || e.cfg.MainConfig == "" || len(deployed) == 0 {
		return nil
	}
	key := ""
	if fi, err := os.Stat(e.cfg.MainConfig); err == nil {
		key = fi.ModTime().String()
	}
	if f := deployed[e.cfg.Paths.MainConfig()]; f != nil {
		key += "|" + f.SHA256
	}
	c := &e.namedCheck
	c.mu.Lock()
	defer c.mu.Unlock()
	if c.key == key && e.Now().Sub(c.at) < namedCheckTTL {
		return c.problems
	}
	res, err := e.tools.CheckConfig(ctx, e.cfg.MainConfig, false)
	if err != nil {
		return nil // named-checkconf couldn't run; an apply reports that
	}
	out := render.Render(st, e.cfg.Paths, e.extras(ctx))
	var ps []validate.Problem
	for _, m := range res.Messages {
		p := validate.Problem{Severity: validate.Warning, Code: "named_warning", View: m.View, Zone: m.Zone}
		if m.Error {
			p.Severity, p.Code = validate.Error, "named_error"
		}
		where := ""
		if m.File != "" {
			where = fmt.Sprintf(" (%s:%d)", m.File, m.Line)
		}
		if span, ok := out.Lookup(m.File, m.Line); ok {
			p.ObjectType, p.ObjectID = span.ObjectType, span.ObjectID
			where = " (" + span.Label + ", " + where[2:]
		}
		p.Message = "named-checkconf: " + strings.TrimSpace(m.Text) + where
		ps = append(ps, p)
	}
	c.key, c.at, c.problems = key, e.Now(), ps
	return ps
}