package check

import (
	"context"
	"errors"
	"fmt"
	"strings"

	"git.novox.be/novox/mesh-delivery/contracts/go/clients/meshcatalogclient"
	"git.novox.be/novox/mesh-sdk/go/catalogue"
)

// declaredPackage is one package a group member declares: the module, its directory in the repository (RootPath for its
// root, empty when not known), and the artifact's name, paths and language.
type declaredPackage struct {
	pull        Pull
	module, dir string
	name        string
	paths       []string
	language    string
}

// manifestAtHead is a touched module's manifest read from the forge at its member's head (the lead's ruling 4 on A2c's
// finding 4): with no preview of the merge, a package new in the group is declared only there, never at the trunk. The
// module's directory is the indexer's when it knows the module, else modules/<module> or the repository's root, the one
// whose manifest names the module. Found is false when no such file names it.
func (st *state) manifestAtHead(ctx context.Context, p Pull, module string) (m catalogue.Manifest, dir string, found bool, err error) {
	var dirs []string
	if st.j.Dirs != nil {
		if d, ok := st.j.Dirs.ModuleDir(module); ok {
			dirs = []string{d}
		}
	}
	if dirs == nil {
		dirs = []string{"modules/" + module, meshcatalogclient.RootPath}
	}
	for _, d := range dirs {
		file := "module.json"
		if t := strings.Trim(d, "/"); t != "" && t != meshcatalogclient.RootPath {
			file = t + "/module.json"
		}
		text, err := st.j.Forge.File(ctx, p.Repository, file, p.Head)
		if errors.Is(err, ErrNotFound) {
			continue
		}
		if err != nil {
			return catalogue.Manifest{}, "", false, fmt.Errorf("the manifest of %s at the head of %s cannot be read%s: %w", module, pullKey(p), unheardWords(err), err)
		}
		m, err := catalogue.Decode([]byte(text))
		if err != nil {
			return catalogue.Manifest{}, "", false, fmt.Errorf("the manifest %s of %s at the head of %s is no manifest: %w", file, module, pullKey(p), err)
		}
		if m.Module == module {
			return m, d, true, nil
		}
	}
	return catalogue.Manifest{}, "", false, nil
}

// declaredPackages are the packages the case's members declare, read from each touched module's manifest at the merge
// preview (the candidate's); with no preview, at the member's head on the forge, so a package new in the group is asked
// for on the first check too (trunk's manifest when no forge is read): a member that declares none is not asked for.
func (st *state) declaredPackages(ctx context.Context) ([]declaredPackage, error) {
	if st.j.Read == nil && st.j.Forge == nil {
		return nil, nil
	}
	var trunk map[string]string
	if st.j.Manifests != nil {
		trunk = st.j.Manifests.ManifestDigests()
	}
	var out []declaredPackage
	for _, p := range st.c.Pulls {
		for _, module := range p.Modules {
			var m catalogue.Manifest
			var dir string
			digest := p.Fps[module].Manifest
			switch {
			case digest != "" && st.j.Read != nil:
				var err error
				if m, err = st.j.Read.Manifest(ctx, digest); err != nil {
					return nil, fmt.Errorf("the manifest of %s (%s) cannot be read, so the packages it declares are not known: %w", module, pullKey(p), err)
				}
			case st.j.Forge != nil:
				var found bool
				var err error
				if m, dir, found, err = st.manifestAtHead(ctx, p, module); err != nil {
					return nil, fmt.Errorf("%v, so the packages it declares are not known", err)
				}
				if !found {
					continue
				}
			case trunk[module] != "" && st.j.Read != nil:
				var err error
				if m, err = st.j.Read.Manifest(ctx, trunk[module]); err != nil {
					return nil, fmt.Errorf("the manifest of %s (%s) cannot be read, so the packages it declares are not known: %w", module, pullKey(p), err)
				}
			default:
				continue
			}
			if dir == "" && st.j.Dirs != nil {
				dir, _ = st.j.Dirs.ModuleDir(module)
			}
			if m.Build == nil {
				continue
			}
			for _, a := range m.Build.Artifacts {
				if a.Kind != catalogue.ArtifactPackage {
					continue
				}
				out = append(out, declaredPackage{pull: p, module: module, dir: dir, name: a.Name, paths: a.Paths, language: a.Language})
			}
		}
	}
	return out, nil
}