package main

import (
	"context"
	"sort"
	"strings"

	"git.novox.be/novox/mesh-sdk/go/catalogue"
	"git.novox.be/novox/mesh-sdk/go/compose"
	"git.novox.be/novox/mesh-sdk/go/overlay"
	"github.com/novox/mesh-controller/internal/inventory"
)

// The second half of the adapter (issue 1383): the credential and build fields of the Input, read and never made.

// readCredentialsAndBuilds fills what the first half left: the credentials, the own secrets, the vault's boxes, the bus,
// each node's serving key and certificate, and the builds.
func readCredentialsAndBuilds(ctx context.Context, open *stores, in *compose.Input, plans map[string]compose.Resolved,
	shape inputShape, busRefused *error) ([]inventory.PairCredential, error) {
	if err := readIdentity(ctx, open, in); err != nil {
		return nil, err
	}
	wouldMake, err := readCredentials(ctx, open, in, plans, busRefused)
	if err != nil {
		return nil, err
	}
	return wouldMake, readBuilds(ctx, open, in, plans, shape)
}

// readIdentity is the mesh's authority and each node's serving key and the certificate kept for it, for a mesh in which a
// module asks for a certificate. It establishes and issues nothing: a certificate not kept yet is composed with a stand-in, and
// issued by the send (certificateFor).
func readIdentity(ctx context.Context, open *stores, in *compose.Input) error {
	needs := false
	for _, m := range in.Catalogue {
		needs = needs || m.Certificate != nil
	}
	if !needs {
		return nil
	}
	ident, err := open.Identity(ctx)
	if err != nil {
		return err
	}
	if certificate, known, err := ident.KnownAuthority(ctx); err != nil {
		return err
	} else if known {
		in.Authority = certificate
	}
	nodes, err := open.inventory.Nodes(ctx)
	if err != nil {
		return err
	}
	ids := map[string]string{}
	for _, n := range nodes {
		ids[n.Name] = n.ID
	}
	for i := range in.Nodes {
		n := &in.Nodes[i]
		if n.ServingKey, err = ident.ServingKeyOf(ctx, ids[n.Name]); err != nil {
			return err
		}
		if n.ServingKey == "" {
			continue
		}
		if certificate, known, err := ident.KeptCertificate(ctx, overlay.InternalName(n.Name), n.ServingKey); err != nil {
			return err
		} else if known {
			n.Certificate = certificate
		}
	}
	return nil
}

// readCredentials is how each pair credential a node takes from elsewhere stands, the credentials made for each provider's
// consumers, the own secrets, the vault's boxes and the bus. It reads and never makes: a credential a send would make is
// left out (the composition's would-make), a credential only a person gives and nobody gave is not-given, and one the send
// would be refused is refused with the controller's words.
func readCredentials(ctx context.Context, open *stores, in *compose.Input, plans map[string]compose.Resolved,
	busRefused *error) ([]inventory.PairCredential, error) {
	var wouldMake []inventory.PairCredential
	inv := open.inventory
	shelf := in.Catalogue
	nodeOf := map[string]compose.Node{}
	for _, n := range in.Nodes {
		nodeOf[n.Name] = n
	}
	names := make([]string, 0, len(plans))
	for name := range plans {
		names = append(names, name)
	}
	sort.Strings(names)
	for _, name := range names {
		resolved := plans[name]
		nodeShelf := shelfWith(shelf, nodeOf[name].Kept)
		for _, need := range resolved.Plan.Needs {
			if need.ByRecord {
				continue
			}
			p := inventory.PairCredential{Name: need.Name, Consumer: name, ConsumerModule: need.For,
				Provider: need.From, Local: need.Local}
			if module, outside := issuedOutsideBy(nodeShelf, need); outside {
				p.Kind, p.ProviderModule = inventory.PairOutside, module
			} else if need.SharedOwn != "" {
				p.Kind, p.Own = inventory.PairShared, need.SharedOwn
				p.ProviderModule = sharedProviderModule(resolved.Plan, shelf, need)
			}
			state, err := inv.PairCredentialState(ctx, p)
			if err != nil {
				return nil, err
			}
			c := compose.Credential{Provision: need.Name, Consumer: name, ConsumerModule: need.For,
				Provider: need.From, Local: need.Local}
			switch state.State {
			case inventory.PairHeld:
				c.State, c.Sealed = compose.CredentialHeld, state.Sealed
			case inventory.PairNotGiven:
				c.State, c.Why = compose.CredentialNotGiven, state.Why
			case inventory.PairRefused:
				c.State, c.Why = compose.CredentialRefused, state.Why
			default:
				// Left out: a need with no entry is the credential the next send makes, and perform makes it.
				wouldMake = append(wouldMake, p)
				continue
			}
			in.Credentials = append(in.Credentials, c)
		}
	}

	// The credentials made for each provider's consumers, so the grants it must create are read from them.
	for _, n := range in.Nodes {
		rows, err := inv.SecretsFrom(ctx, n.Name)
		if err != nil {
			return nil, err
		}
		for _, s := range rows {
			in.Issued = append(in.Issued, compose.Issued{Provision: s.Name, Consumer: s.Consumer,
				ConsumerModule: s.ConsumerModule, Local: s.Local, Provider: n.Name, ForProvider: s.ForProvider})
		}
	}
	own, err := inv.OwnSecretRows(ctx)
	if err != nil {
		return nil, err
	}
	for _, r := range own {
		in.OwnSecrets = append(in.OwnSecrets, compose.OwnSecretRow{Node: r.Node, Module: r.Module, Name: r.Name,
			Origin: r.Origin, SealedTo: r.SealedTo, Sealed: r.Sealed})
	}
	for _, n := range in.Nodes {
		boxes, err := inv.KeptCoreBoxes(ctx, n.Name)
		if err != nil {
			return nil, err
		}
		for module, byName := range boxes {
			for name, b := range byName {
				in.KeptCoreBoxes = append(in.KeptCoreBoxes, compose.CoreBox{Node: n.Name, Module: module, Name: name,
					Generation: b.Generation, SealedTo: b.SealedTo, Box: b.Box})
			}
		}
	}
	sort.Slice(in.KeptCoreBoxes, func(i, j int) bool {
		a, b := in.KeptCoreBoxes[i], in.KeptCoreBoxes[j]
		if a.Node != b.Node {
			return a.Node < b.Node
		}
		if a.Module != b.Module {
			return a.Module < b.Module
		}
		return a.Name < b.Name
	})

	// The bus: its user list as the controller composes it, for the machine that runs it, and who the mesh has minted a
	// credential for.
	var bus []catalogue.Manifest
	for _, m := range shelf {
		if m.BusUsers != "" && m.ClaimsSeat("mesh-broker") {
			bus = append(bus, m)
		}
	}
	if len(bus) > 0 {
		list, missing, err := busUserList(ctx, inv, bus)
		if err != nil && !strings.Contains(err.Error(), "not one user has a credential") {
			return nil, err
		}
		if err != nil {
			// The machine that runs the bus is refused, as the controller's own composition refused it: a list that
			// refuses every connection in the mesh is never composed (refusedBus); the other machines compose.
			*busRefused = err
		}
		in.BusUsers, in.BusMissing = list, missing
	}
	if in.BusMinted, err = inv.BusMinted(ctx); err != nil {
		return nil, err
	}
	if in.BusMemberships, err = inv.BusMemberships(ctx); err != nil {
		return nil, err
	}
	return wouldMake, nil
}

// readBuilds is the build half of the Input: every repository the mesh built, each module's current build, and the build made
// from a commit of a module for the machines whose node-engine reads them.
func readBuilds(ctx context.Context, open *stores, in *compose.Input, plans map[string]compose.Resolved, shape inputShape) error {
	inv := open.inventory
	held, err := inv.Held(ctx)
	if err != nil {
		return err
	}
	for repository := range held {
		in.Built = append(in.Built, repository)
	}
	sort.Strings(in.Built)
	in.CurrentBuilds = make(map[string]string, len(shape.current))
	for module, b := range shape.current {
		in.CurrentBuilds[module] = b.Commit
	}
	// The build made from each commit a declaration may carry, for the machines that read a build per module.
	for _, n := range in.Nodes {
		if !n.ReadsModules {
			continue
		}
		resolved, ok := plans[n.Name]
		if !ok {
			continue
		}
		for _, m := range resolved.Plan.Modules {
			for _, commit := range []string{shape.current[m.Module].Commit, shape.kept[n.Name][m.Module], shape.sent[n.Name][m.Module]} {
				if commit == "" {
					continue
				}
				if _, done := in.BuildIDs[m.Module][commit]; done {
					continue
				}
				build, err := inv.BuildOf(ctx, m.Module, commit)
				if err != nil {
					return err
				}
				if in.BuildIDs == nil {
					in.BuildIDs = map[string]map[string]string{}
				}
				if in.BuildIDs[m.Module] == nil {
					in.BuildIDs[m.Module] = map[string]string{}
				}
				in.BuildIDs[m.Module][commit] = build
			}
		}
	}
	return nil
}

// shelfWith is the shelf with each module a node keeps at the build it runs put in place of the current one: a copy.
func shelfWith(shelf map[string]catalogue.Manifest, kept map[string]catalogue.Manifest) map[string]catalogue.Manifest {
	if len(kept) == 0 {
		return shelf
	}
	out := make(map[string]catalogue.Manifest, len(shelf)+len(kept))
	for name, m := range shelf {
		out[name] = m
	}
	for name, m := range kept {
		out[name] = m
	}
	return out
}

// sharedProviderModule is which module answers a shared credential on the providing node: the one in the plan, else the first
// the catalogue names (providerModuleOf, in an order that does not move between calls).
func sharedProviderModule(plan catalogue.Resolution, shelf map[string]catalogue.Manifest, n catalogue.Needed) string {
	for _, m := range plan.Modules {
		if _, shared := m.SharedCredentialOf(n.Name); shared {
			return m.Module
		}
	}
	names := make([]string, 0, len(shelf))
	for name := range shelf {
		names = append(names, name)
	}
	sort.Strings(names)
	for _, name := range names {
		if _, shared := shelf[name].SharedCredentialOf(n.Name); shared {
			return name
		}
	}
	return ""
}