package releasekit

import (
	"context"
	"io"

	internalbuild "gitea.maximumdirect.net/eric/ReleaseKit/internal/build"
	"gitea.maximumdirect.net/eric/ReleaseKit/internal/candidate"
	"gitea.maximumdirect.net/eric/ReleaseKit/internal/publish"
	"gitea.maximumdirect.net/eric/ReleaseKit/internal/validation"
)

// ErrInvalidVersion reports a version that is not stable vMAJOR.MINOR.PATCH.
var ErrInvalidVersion = candidate.ErrInvalidVersion

// ErrUnexpectedPushURL reports that the effective publication push URL does
// not exactly match ReleaseRequest.ExpectedPushURL.
var ErrUnexpectedPushURL = publish.ErrUnexpectedPushURL

// Candidate identifies one committed local source revision selected for
// validation.
type Candidate struct {
	RepositoryDir string
	Commit        string
	Version       string
}

// ReleaseRequest contains the inputs used to validate and optionally build one
// local candidate. Remote is retained for publication operations; Check makes
// no remote availability claim.
type ReleaseRequest struct {
	RepositoryDir string
	Product       string
	Version       string
	Remote        string
	// ExpectedPushURL optionally requires Publish's resolved push URL to match
	// this string exactly before validation or tag creation. Check ignores this
	// publication-only expectation. A mismatch returns ErrUnexpectedPushURL.
	ExpectedPushURL string
	// Validation selects optional checks run against the captured candidate.
	Validation ValidationSpec
	// AdditionalChecks optionally runs product checks after shared validation.
	AdditionalChecks func(context.Context, Candidate) error
	Build            *BuildSpec // optional selected-target build after validation.
	Output           io.Writer
}

// ValidationSpec selects optional shared validation checks. Its zero value
// preserves the current validation behavior.
type ValidationSpec struct {
	Go GoValidationSpec
	// GoFormat checks the formatting of committed regular Go source files. It
	// does not modify repository contents and is disabled when false.
	GoFormat bool
	// Markdown selects committed Markdown destination and fragment checking.
	// Nil disables the check; an empty object enables it with the default
	// behavior, reporting outside-checkout destinations as out of scope.
	Markdown *MarkdownValidationSpec
	// ModuleDistribution selects checks for files that affect module-source
	// distribution. Its zero value disables those checks.
	ModuleDistribution ModuleDistributionValidationSpec
	// FileSize selects a committed-file size check. Nil disables it; an empty
	// object selects the 1,000,000-byte default.
	FileSize *FileSizeValidationSpec
}

// MarkdownValidationSpec selects behavior for committed Markdown links.
type MarkdownValidationSpec struct {
	// EnforceCheckoutBoundary fails when a local destination resolves outside
	// the candidate checkout. Submodule contents remain out of scope.
	EnforceCheckoutBoundary bool
}

// FileSizeValidationSpec selects a maximum size for each committed blob.
type FileSizeValidationSpec struct {
	// LimitBytes is the maximum decimal byte count. Nil selects 1,000,000;
	// zero is a zero-byte limit, and negative values are invalid.
	LimitBytes *int64
	// Exclusions are literal repository-relative file or directory paths.
	// A directory exclusion includes committed descendants.
	Exclusions []string
}

// ModuleDistributionValidationSpec selects independent module-source
// distribution checks.
type ModuleDistributionValidationSpec struct {
	// WorkspaceFiles rejects committed go.work and go.work.sum blobs, including
	// nested paths and symlink entries. It does not select Go's test workspace.
	WorkspaceFiles bool
	// LocalReplacements rejects filesystem replacements in committed go.mod
	// declarations, including nested modules. It does not select Go's workspace.
	LocalReplacements bool
}

// GoValidationSpec selects checks performed by the Go toolchain.
type GoValidationSpec struct {
	// Race runs the one standard Go test suite with the race detector enabled.
	Race bool
	// FullVet runs go vet after the suite instead of the test-time vet pass.
	// Failures use the go-vet validation check identity.
	FullVet bool
	// CompileTargets checks that every package builds for each complete target
	// pair after testing and vet. Compilation uses CGO_ENABLED=0 and does not
	// produce artifacts or execute target binaries. Failures use the
	// package-compile validation check identity.
	CompileTargets []Target
}

// Check validates one local, committed release candidate. It requires a clean
// worktree and index on main, a committed note matching Product and Version,
// and an unused local tag. It always runs the offline Go test suite with the
// available compatible local Go toolchain and Go host target, then calls
// AdditionalChecks when supplied. Validation.Go.Race runs that one suite with
// the race detector, Validation.Go.FullVet runs go vet after the suite instead
// of test-time vet, and Validation.Go.CompileTargets compiles all packages for
// each selected GOOS/GOARCH pair after tests and vet with cgo disabled. Package
// compilation produces no artifacts and does not execute target binaries.
// Validation.GoFormat checks regular committed Go source after those selected
// Go checks and before AdditionalChecks. Its zero value disables formatting.
// Validation.ModuleDistribution.WorkspaceFiles rejects committed workspace
// files after formatting. Its zero value disables that distribution check and
// does not change Go's workspace environment.
// Validation.ModuleDistribution.LocalReplacements parses committed go.mod
// declarations, including nested modules, and rejects filesystem replacements
// after workspace-file inspection. Its zero value disables that check.
// Validation.FileSize checks each selected committed blob after module
// distribution checks. Its nil value disables size checks; an empty object
// enables the default limit.
// Validation.Markdown checks committed local Markdown destinations and
// supported fragments after file-size inspection and before AdditionalChecks.
// Nil disables the check; an empty object enables it. Outside-checkout
// destinations are reported as out of scope unless the selected specification
// enforces the checkout boundary. Submodule contents remain out of scope.
// The zero values of all selections preserve the ordinary suite. If
// Build selects targets, Check builds them after validation in temporary
// storage outside the worktree, then rechecks
// branch, HEAD, worktree, index, and local tag state. Success establishes local
// candidate evidence only; it does not establish remote availability.
func Check(ctx context.Context, request ReleaseRequest) (Candidate, error) {
	checked, err := candidate.Check(ctx, candidateRequest(request))
	if err != nil {
		return Candidate{}, convertValidationError(err)
	}
	return Candidate{
		RepositoryDir: checked.RepositoryDir,
		Commit:        checked.Commit,
		Version:       checked.Version,
	}, nil
}

func candidateRequest(request ReleaseRequest) candidate.Request {
	fileSize := internalFileSizeSettings(request.Validation.FileSize)
	result := candidate.Request{
		RepositoryDir: request.RepositoryDir,
		Product:       request.Product,
		Version:       request.Version,
		Validation: validation.Settings{
			Race:           request.Validation.Go.Race,
			FullVet:        request.Validation.Go.FullVet,
			CompileTargets: make([]validation.Target, len(request.Validation.Go.CompileTargets)),
			GoFormat:       request.Validation.GoFormat,
			Markdown:       internalMarkdownSettings(request.Validation.Markdown),
			ModuleDistribution: validation.ModuleDistributionSettings{
				WorkspaceFiles:    request.Validation.ModuleDistribution.WorkspaceFiles,
				LocalReplacements: request.Validation.ModuleDistribution.LocalReplacements,
			},
			FileSize: fileSize,
		},
		AdditionalChecks: candidateChecks(request.AdditionalChecks),
		AfterValidate:    internalbuild.CandidateCallback(internalBuildSpec(request.Build), request.Output),
		Output:           request.Output,
	}
	for index, target := range request.Validation.Go.CompileTargets {
		result.Validation.CompileTargets[index] = validation.Target{OS: target.OS, Arch: target.Arch}
	}
	return result
}

func internalMarkdownSettings(spec *MarkdownValidationSpec) *validation.MarkdownSettings {
	if spec == nil {
		return nil
	}
	return &validation.MarkdownSettings{EnforceCheckoutBoundary: spec.EnforceCheckoutBoundary}
}

func internalFileSizeSettings(spec *FileSizeValidationSpec) *validation.FileSizeSettings {
	if spec == nil {
		return nil
	}
	var limitBytes *int64
	if spec.LimitBytes != nil {
		limit := *spec.LimitBytes
		limitBytes = &limit
	}
	return &validation.FileSizeSettings{
		LimitBytes: limitBytes,
		Exclusions: append([]string(nil), spec.Exclusions...),
	}
}

func candidateChecks(checks func(context.Context, Candidate) error) func(context.Context, candidate.Candidate) error {
	if checks == nil {
		return nil
	}
	return func(ctx context.Context, captured candidate.Candidate) error {
		return checks(ctx, Candidate{
			RepositoryDir: captured.RepositoryDir,
			Commit:        captured.Commit,
			Version:       captured.Version,
		})
	}
}