package releasekit

import (
	"context"
	"io"

	internalbuild "gitea.maximumdirect.net/eric/ReleaseKit/internal/build"
	internaldelivery "gitea.maximumdirect.net/eric/ReleaseKit/internal/delivery"
	"gitea.maximumdirect.net/eric/ReleaseKit/internal/gitea"
)

// DeliveryState describes the result of one delivery invocation.
type DeliveryState string

const (
	// DeliveryNotAttempted means this invocation made no remote write.
	DeliveryNotAttempted DeliveryState = "not_attempted"
	// DeliveryComplete means the release page and all declared assets match.
	DeliveryComplete DeliveryState = "complete"
	// DeliveryPartial means a page or some assets were delivered, with work pending.
	DeliveryPartial DeliveryState = "partial"
	// DeliveryConflict means existing hosted content differs from the declaration.
	DeliveryConflict DeliveryState = "conflict"
	// DeliveryUnknown means a remote write may have succeeded but could not be resolved.
	DeliveryUnknown DeliveryState = "unknown"
)

// GiteaDestination supplies the hosted repository and explicit access token.
type GiteaDestination struct {
	BaseURL    string
	Owner      string
	Repository string
	Token      string
}

// DeliveryAsset identifies a hosted asset by filename and SHA-256 digest.
type DeliveryAsset struct {
	Filename string
	SHA256   string
}

// DeliveryRequest identifies a local tagged checkout and its explicit Gitea
// destination. Build selects a managed build; Prebuilt supplies caller-owned
// build output instead. They cannot both be set. Either may be nil for
// page-only delivery when both are nil. Build with no targets, or an empty
// Prebuilt result, also performs page-only delivery.
type DeliveryRequest struct {
	RepositoryDir string // directory within the tagged source Git checkout.
	// ModuleDir selects a repository-relative module directory; empty selects
	// the repository root.
	ModuleDir string
	Product   string
	Version   string
	// ExpectedTag optionally requires the full CI event tag to match the
	// selected module's derived tag before building or making hosted requests.
	ExpectedTag string
	Destination GiteaDestination
	// Build selects binaries to build in temporary storage outside the checkout.
	Build *BuildSpec
	// Prebuilt supplies an existing build whose files remain caller-owned.
	Prebuilt *BuildResult
	// Output receives progress from a managed build.
	Output io.Writer
}

// DeliveryResult reports hosted content and the state reached by this
// invocation. A partial result may accompany an error. The asset slices are
// current observations: an asset appears in at most one slice, and early
// failures may leave some declared assets unreported.
type DeliveryResult struct {
	RepositoryDir   string
	ModuleDir       string
	ModulePath      string
	Tag             string // complete derived Git tag.
	Version         string // selected stable semantic version.
	CandidateCommit string
	ReleaseURL      string
	State           DeliveryState
	// Matching lists existing attachments with the declared content.
	Matching []DeliveryAsset
	// Uploaded lists assets whose uploads were confirmed during this invocation.
	Uploaded []DeliveryAsset
	// Pending lists assets known to be missing.
	Pending []DeliveryAsset
	// Conflicting lists assets with detected content conflicts.
	Conflicting []DeliveryAsset
	// Uncertain lists assets whose remote state could not be resolved.
	Uncertain []DeliveryAsset
}

// Deliver verifies the selected local tag and hosted source, then creates or
// finds its release page and adds any missing declared build assets. Build
// requests are compiled into temporary storage that Deliver removes on return.
// Prebuilt artifacts remain caller-owned and are not removed. Both paths
// validate source identity and artifact contents before hosted writes.
// Module selection and declaration links resolve from the captured commit.
// Page-only delivery can use a sparse checkout with available committed objects;
// managed builds require their selected source files in the working tree.
func Deliver(ctx context.Context, request DeliveryRequest) (DeliveryResult, error) {
	result := DeliveryResult{Version: request.Version, State: DeliveryNotAttempted}
	destination := gitea.Destination{
		BaseURL: request.Destination.BaseURL, Owner: request.Destination.Owner,
		Repository: request.Destination.Repository, Token: request.Destination.Token,
	}
	var prebuilt *internalbuild.Result
	if request.Prebuilt != nil {
		prebuilt = internalBuildResult(*request.Prebuilt)
	}
	internalResult, err := internaldelivery.Deliver(ctx, internaldelivery.Request{
		RepositoryDir: request.RepositoryDir,
		ModuleDir:     request.ModuleDir,
		Product:       request.Product,
		Version:       request.Version,
		ExpectedTag:   request.ExpectedTag,
		Destination:   destination,
		Build:         internalBuildSpec(request.Build),
		Prebuilt:      prebuilt,
		Output:        request.Output,
	})
	result.RepositoryDir = internalResult.RepositoryDir
	result.ModuleDir = internalResult.ModuleDir
	result.ModulePath = internalResult.ModulePath
	result.Tag = internalResult.Tag
	result.CandidateCommit = internalResult.CandidateCommit
	result.ReleaseURL = internalResult.ReleaseURL
	result.State = DeliveryState(internalResult.State)
	result.Matching = deliveryAssets(internalResult.Matching)
	result.Uploaded = deliveryAssets(internalResult.Uploaded)
	result.Pending = deliveryAssets(internalResult.Pending)
	result.Conflicting = deliveryAssets(internalResult.Conflicting)
	result.Uncertain = deliveryAssets(internalResult.Uncertain)
	return result, err
}

func deliveryAssets(assets []gitea.AssetIdentity) []DeliveryAsset {
	result := make([]DeliveryAsset, 0, len(assets))
	for _, asset := range assets {
		result = append(result, DeliveryAsset{Filename: asset.Filename, SHA256: asset.SHA256})
	}
	return result
}