package grants

import (
	"fmt"
	"slices"
	"sort"
	"strings"

	"mesh-grants/internal/buscompose"

	occ "git.novox.be/novox/mesh-contracts/operator-and-conversation/go/clients/operatorchannelclient"
	oc "git.novox.be/novox/mesh-contracts/operator-and-conversation/go/seats/operatorchannel"
)

// **A module whose manifest waits or is refused keeps its bus users** (clause 3 of the record on a release's Approve; issue
// 774). The indexer holds a manifest it refuses, or that waits for a judge that knows a field of it, out of the manifests
// the part composes from (inputs.go, Refused), so a module with no want naming a build had no manifest to derive its users
// from and its users left the list: the bus module's accounts among them, which locked its tools out. Now such a module's
// users, the ones the list in force carries, stay in the list as it holds them, the same way a refused principal's do
// (refused.go), and the part says so as the warning mesh-grants.module-held until the manifest is accepted. One module's
// manifest never holds the list: every other principal is composed as ever. A module whose want names a build is composed
// from the manifest of that build (Inputs.Running), not kept.

// HeldModuleCondition is the key of the warning raised while a module's manifest is held and its users are kept.
const HeldModuleCondition = "mesh-grants.module-held"

// heldModuleUsers are, by user, why it is kept: the users of candidates (the ones the list in force and the bus carry) that
// belong to a module placed on a node whose manifest the indexer holds (in.Refused) and whose want names no build. A user of
// a module on a node is `<node>.<module>` or `<node>.<module>.<process>` (buscompose.Principal.Username). Pure.
func heldModuleUsers(in Inputs, candidates []string) map[string]string {
	held := map[string]string{}
	for _, g := range in.Refused {
		if module, ok := strings.CutPrefix(g.Input, "manifest of "); ok {
			held[module] = g.Why
		}
	}
	out := map[string]string{}
	if len(held) == 0 {
		return out
	}
	for node, modules := range in.Assigned {
		for _, module := range modules {
			why, ok := held[module]
			if !ok {
				continue
			}
			if _, runs := in.Running[node+"."+module]; runs {
				continue
			}
			prefix := node + "." + module
			// No manifest of the module can be read at all (the trunk's is refused and no running build's is found): named
			// unreadable, in the condition and in grants_user_list (ADR 0614 §8).
			state := "held"
			if _, readable := in.Held[module]; !readable {
				state = "unreadable"
			}
			for _, user := range candidates {
				if user == prefix || strings.HasPrefix(user, prefix+".") {
					out[user] = fmt.Sprintf("the manifest of %s is %s: %s", module, state, why)
				}
			}
		}
	}
	return out
}

// runnerUsersKept are, by user, why it is kept: on a node where no placed module's manifest says it is the tool runner
// (`tool-runner`), the user of the list in force that is that node's tool runner, known by what runs (it may say the runner
// is alive, buscompose.ToolsAliveSubject, which the runner alone is granted), never by a module's name (ADR 0601 §4). A
// manifest that does not yet say what shared code no longer infers keeps the runner as it runs, said in the held module's
// condition, and is never composed without it. Pure.
func runnerUsersKept(recs buscompose.Records, inForce map[string]User) map[string]string {
	out := map[string]string{}
	for node, placed := range recs.Assigned {
		if slices.ContainsFunc(placed, func(d buscompose.Declared) bool { return d.ToolRunner }) {
			continue
		}
		alive := buscompose.ToolsAliveSubject(node)
		for user, u := range inForce {
			if strings.HasPrefix(user, node+".") && slices.Contains(u.Publish, alive) {
				out[user] = fmt.Sprintf("no manifest placed on %s says it is the tool runner (tool-runner), so the tool runner keeps "+
					"what it runs until its manifest says so", node)
			}
		}
	}
	return out
}

// inForceGrants are the grants of each user of the list in force as the part sealed them, or nil where it kept none.
func (p *Part) inForceGrants() map[string]User {
	if g, _, had := p.Sealed(); had && g.Digest != "" && p.Store != nil {
		inForce, _ := p.sealedGrantsOf(g.Digest)
		return inForce
	}
	return nil
}

// mergedRefusals is refused and held in one map, for the parts that keep a user's grants of the list in force.
func mergedRefusals(refused, held map[string]string) map[string]string {
	if len(held) == 0 {
		return refused
	}
	out := make(map[string]string, len(refused)+len(held))
	for u, why := range held {
		out[u] = why
	}
	for u, why := range refused {
		out[u] = why
	}
	return out
}

// sayHeldModules raises HeldModuleCondition while a held module's users are kept, naming each user with what became of it,
// and clears it once none is; said once per set, again when it changes, and at the first pass after a start.
func (p *Part) sayHeldModules(held map[string]string, kept map[string]User) {
	if p.Say == nil {
		return
	}
	var lines []string
	users := make([]string, 0, len(held))
	for u := range held {
		users = append(users, u)
	}
	sort.Strings(users)
	for _, user := range users {
		became := "not in the list in force and left out"
		if _, ok := kept[user]; ok {
			became = "stays in the list as the list in force holds it"
		}
		lines = append(lines, user+" ("+became+"): "+held[user])
	}
	why := strings.Join(lines, "; ")
	p.holdMu.Lock()
	defer p.holdMu.Unlock()
	if p.heldModulesKnown && why == p.heldModulesSaid {
		return
	}
	c := oc.Condition{Key: HeldModuleCondition, Subject: oc.ConditionSubject{Scope: "module", ID: "mesh-grants"}}
	if why == "" {
		c.State = occ.StateCleared
	} else {
		c.Severity, c.State = occ.SeverityWarning, occ.StateRaised
		c.Summary = fmt.Sprintf("%d bus user(s) of a module whose manifest is held are kept in the list: %s", len(users), why)
		c.Headline, c.Needs = "A module's manifest is held, its bus users are kept", "a manifest the indexer accepts, or a judge that knows its fields"
		c.Explanation = occ.NeedsYou + "a manifest the indexer accepts (a refused one mended, or a waiting one judged by an indexer that knows its fields). " +
			"The rest of the user list is written as ever; a held module's users stay as the list in force holds them: " + why
		c.Resolved = "every module's manifest is accepted"
	}
	if p.Say(c) == nil {
		p.heldModulesSaid, p.heldModulesKnown = why, true
	}
}